Radio-Electronics-19

TECHNOLOGY - VIDEO STEREO- COMPUTERS - SERVICE BUILD THIS COMPUTERIZED IC TESTER Troubleshoot IC's in or out of circuit THE TRUTH BEHIND THE BLUE BOX And how Ma Bell crushed them

RF TRANSISTORS GERNSBACK PUBLICATION Understanding the data sheets ATI SURFACE -MOUNT * -TECHNOLOGY Forrest Mims brings you the technology and 4 projects you can build

COMPUTERDIGEST Turbocharging your PC

PLUS: * BUILD AN ELECTRONIC LOCK, * POOR MAN'S STORAGE SCO /E./ * SEMICONDUCTOR TESTING NOW GET SCOPE, COUNTER AND DMM INPUT AU. AT ONCE THROUGH ONE PROBE!

1238 8

Gated frequency measurement. Delay time measurement. Delay Channel 1 dc volts measure- B sweep triggering during the time from the start of A sweep to ment. The average dc compo- intensified portion of the A sweep. the start of the B sweep is mea- nent of a waveform is measured Intensified portion frequency is sured with crystal accuracy. directly through channel 1 with measured with the counter/timer/ direct digital fluorescent readout. DMM.

The Tek 2236 combines surements to 0.1%. 100 MHz, dual timebase A built-in, auto -ranging scope capability with ohmmeter provides counter timer/DMM measurements functions integrated into from 0.01 n to 2G1/ -as its vertical, horizontal well as audible continuity. and trigger systems. For Automatic diode/junction the same effort it takes to detection and operator display a waveform you prompts serve to simplify can obtain digital readout set-up and enhance of frequency, period, confidence in your width, totalized events, measurements delay time and A -time to The 2236: scope, accuracies of 0.001%. counter, timer, DMM The same probe is plus a 3 -year warranty used to provide input for the -all for just $2,650. CRT display and the digital Bandwidth 100 MHz Contact your nearest dis- measurement system, No of Channels 2 + Trig. View tributor or call Tek toll -free. resulting in easy set-up, Max. Sweep Speed 5 ns/div Technical personnel on our greater measurement confi- Digital Direct Ch 1 Voltage Meas. 0.5% DC; 2.0% direct -line will answer your dence and reduced circuit Readout AC RMS questions and expedite loading. Probe tip volts can Features Resistance: .010 to 200 Meg0 delivery. Orders include Continuity/Temp: Audible/C° or F° probes, 30 -day free trial and also be measured through Totalizing Counter: -1 counts to 8,000,000 the Ch 1 input. Direct Freq. Meas: 100 MHz to 0.001% acc. service worldwide. Precision measurements Period, Width Meas: 10 ns with 10 ps max Call Tek direct: at the touch of a button. resolution Auto -ranging frequency, Timing Meas. .001% (delay and s -time with readout) 1-800-433-2323 for period, width and gated Accuracy video tape or literature, measurements are push- Trigger Modes P -P Auto, Norm, TV Field, TV Line, Single Sweep 1-800-426-2200 for button -simple. And the 2236 application assistance or 7.3 kg (16.2 Ib) offers an independent float- Weight ordering information. ing 5000 count, auto -rang- Price $2650 ing multimeter with side Warranty 3 -year including CRT (plus optional service In Oregon, call collect: inputs for DC voltage mea- plans to 5 years) 1-627-2200 Tektronix' COMMIT III) Ill I XLELLENGE

COMPUTERDiait SEW isIMO 0$ .S.C.SPISTI row if LECTS0000, S 106$ ASSOIs.. 43 IN -CIRCUIT DIGITAL -IC TESTER A computerized tester for TTL IC's Bill Green 107 ELECTRONIC COMBINATION LOCK An electronic lock that's opened with an electronic key. Paul Renton

Ht ifFiTtfi 49 THE BLUE BOX AND MA BELL Pirates on the telephone lines. PAGE 91 Herb Friedman, Communications Editor 57 SPECIAL SECTION: SURFACE MOUNT TECHNOLOGY > I. An introduction to the packaging revolution Radio 7 '4 Forrest Mims, III Electronic; 113 POOR MAN'S STORAGE SCOPE Give your standard scope the power of more complex instruments. Duke Bernard ANDHIE 109 UNDERSTANDING DATA SHEETS OF RF POWER -AN TRANSISTORS INTOODUCTI What data sheet parameters mean, and how they're derived. CKAGING REVOLUTION Norman E. Dye, Motorola Semiconductor Products 115 TESTING SEMICONDUCTORS PAGE 57 Op -amp AC parameters. TJ Byers

- AND MORE DEP 1 IILI ;1/i 152 Advertising and Sales 6 VIDEO NEWS 33 AUDIO UPDATE Offices What's new in this fast - Stereo imaging. changing field. Larry Klein 152 Advertising Index David Lachenbruch 39 ANTIQUE RADIOS 153 Free Information Card 14 EQUIPMENT REPORTS Restoring a classic, part 2. 122 Kit Report NCM Model 871 Pattern Richard D. Fitch 8 Letters Generator. 41 DESIGNER'S NOTEBOOK 31 NEW IDEA An under -voltage monitor 131 Market Center Multi -tone generator. Robert Grossblatt 22 New Products 32 SERVICE LOG 124 STATE OF SOLID STATE 127 PC Service Surface -mount components. A bang -bang IC. Robert F. Scott 4 What's News

1 Radio ON THE COVER Electronics Hugo Gernsback(1884-1967) f °under Troubleshooting a complex piece M. Harvey Gernsback. of electronics equipment is seldom editor -in -chief. emeritus Radio .N114easy. But when the circuit contains a Larry Steckler, EHF, CET. number of IC's, all soldered securely editor -in -chief and publisher Electron's' to a PC board, it can become a BLED 114S EDITORIAL DEPARTMENT CONFHlTERIZED r nightmare. This month we'll present IC TESTER a digital IC tester that can assess Art Kleiman, editorial director Brian C. Fenton, managing editor THE TRUTH 13*EN.,, the condition of an IC, in circuit or TM SLUE BCC Carl Laron, WB2S1.11. associate editor out. What's more, it can be built at a Jeffrey K. Holtzman, RE TRANS4STor, very reasonable cost. The story be- assistant technical editor

SURFACE -MOUNT * gins on page 43. Marc Spiwak, associate editor TECHNOLOGY Also this month, our special sec- Robert A. Young, assistant editor tion on Surface Mount Technology Julian S. Martin, editorial associate focuses on one of the most impor- Byron G. Weis, editorial associate tant advances in component pack- M. Harvey Gernsback, Elati: 71.044. contributing editor AR, S.11144,roDoCrts, rtlalC. aging. Written by noted author Jack Darr. CET. service editor Forrest Mims, III, the special sec- Robert F. Scott, tion begins on page 57. semiconductor editor Herb Friedman, communications editor Bob Cooper, Jr. satellite -TV editor "if iLT, Robert Grossblatt, circuits editor Larry Klein, audio editor David Lachenbruch, contributing editor THE DECEMBER ISSUE Richard D. Fitch, contributing editor IS ON SALE Teri Scaduto, editorial assistant

NOVEMBER 3 PRODUCTION DEPARTMENT Ruby M. Yee, production director Robert A. W. Lowndes, BUILD THE MACRO -SCRUBBER editorial production Stabilize Macrovision-encoded videotapes for best viewing. Andre Duzant, technical illustrator Ronald Dee, assistant technical illustrator BUILD A DIGITAL IC TESTER Karen Tucker. advertising production Part 2 shows you how to program and use the tester. Marcella Amoroso, production traffic

CIRCULATION DEPARTMENT Jacqueline P. Cheeseboro, ALL ABOUT STRAIN GAGES circulation director What they are and how they are used. Wendy Alanko, circulation analyst Theresa Lombardo, circulation assistant COMPUTERDIGEST Typography by Mates Graphics All about disk storage. Cover photos by Nick Koudis and Forrest Mims Ill

As a service to readers. RADIO -ELECTRONICS publishes available plans or information relating to newsworthy prod, techniques and scientific and technological developments Because of possible variances in the quality and condition Radio -Electronics is indexed in materials and workmanship used by readers. RADIO -ELECTRONICS disclaims any responsibility for the safe and proper functioning of reader -built protects based upon or from plans or information published in this magazine. Applied Science & Technology Index and Readers Guide to Periodical Liter- Since some of the equipment and circuitry described in RADIO -ELECTRONICS may relate to or be covered by U.S patents. ature. RADIO -ELECTRONICS disclaims any liability for the infringement of such patents by the making. using. or selling of any such equipment or circuitry. and suggests that anyone interested 111 such protects consult a patent attorney Microfilm 8 Microfiche editions are available. Contact circulation depart- RADIO -ELECTRONICS. (ISSN 0033.7862) November 1987. Published monthly by Gernsback Publications. Inc. 500- B Bi-County Boulevard. Farmingdale. NY 11735 Second -Class Postage paid at Farmingdale. NY and additional mailing offices ment for details. Second -Class mail registration No 9242 authorized at Toronto. Canada One-year subscription rate USA and possessions $16.97. Canada $22 97. all other countries 525.97. All subscription orders payable in U.S.A. funds only. via international postal money order or check drawn on a U.S.A.bank. Single copies S2.25 1987 by Gernsback Publications. Inc All rights reserved Advertising Sales Offices listed Printed in U S A on page 152.

POSTMASTER: Please send address changes to RADIO -ELECTRONICS. Subscription DeptBox 55115 Boulder. CO 80321-5115 A stamped self-addressed envelope must accompany all submitted manuscripts and/or artwork or photographs if their return is desired should they be rejected We disclaim any responsibility for the loss or damage of manuscripts and/or artwork or photographs while in our possession or otherwise ,111

2 TEST EQ PMENT THAT MEASURES UP TO YOUR SPECIFICATIONS

egrallilMENTS omm--cro

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OMM-300 $79.95DMM-200 $49.95DMM-700 $49.95DMM-100 $29.95 3. 5 3,G T DMA4 MULTITESTEc 3.5 DIG 'T FULL FUNCTION DMM 3.5 D13.T AUTORAVGANG 0A1M 3.5 D'GIT .DOCKET SIZE DMA4 3er best rucdel. A highly a:curate, fUlfer c Hight ccura:y. 20 amp current capability and Autoranga ccnvenience or fully /larval oper- Shirt-pDcket partabilty with to compronese cl DM VI loaded with many extra feaures mar y range settings make this model ideal for ation.Selectable LO OH N mode permits in features or accuracy. Lame, easy to read cortinuity, capacitance, tra teistor serious bench or field workTilt stand for seaman r -c mon resstarce measurements .5" LC 3 display 2000 hour 3atiery kfe with 7( rvervu-eand cor ductar ce all in one hard hands -free operation. 2000 hour battery life involvinremi-conductor Junctions. MEM standa d 9v ell pr Deices over two years cA 1 -ad reefer lemperature probe, test leads ale with, standard 5.v cellProbes and battery mode fo rueasurements relative to a specific average use. Fecbes and ban cry includel Da hey Mc scled included. reading. Pubes and batter, and tder. - Basic DC acuracy- plus or minus 0.5% Basic DC 4cm-racy: Plus or minus G25°,,, Basc DC accuracy: plus or minus 0.25% Basic 3C accuracy: plus or minus 0 5°'. DC shltage- 2, 1000v, 4 ranges AC voltage: 200s 750v, 2 ranges DC vOteg I: 200rw - 1000v, 5 ra DC ranges DC vane le 200mv -1000v aLbrincaing AC vekege: 200rw 750v, 5 ranges AC voltage: 200mv -750v, 5 ranges or 5 manual ranges Resistasce: ?Si ohms- 2Mohms. 4 mopes Ilesicarce, 200 ohms -- 20M ohrr s Resstarce: 2C0 ohms- 20M ohms, * AC yr:hate 2v 750v, auto anglin.) DC current: 2mA 2A, 4 rarges ramei 6 ranges or 4 manual range. Fully over-1©c pr -D ected AC/MC current. 200aA --- 10A, 6 anges AC: DC current: 200uA -20A. 6 ranges Resisten ze, 200 ohms 201/1 ohms, Inpir impedance, ohn CapaOtence: 2000pf -- 20uf, 3 rar gee Fully over -load protected autorancing 130 x 75 x 28mrn weighs 195 grams -raniestce tester: riFE test, NPN. PMP Input impedance: 10M ohm AC/DC current: 20mA 10A. 2 ranges -emperature tester: 0° -2000° F 18C x 86 x 37mm. weighs 320 grams Fully over -load protected Conductance: 200ns Audible continuity tester Filly Dyerloac protected Input .mpedance: 10M ohm Input impedance' 10M ohm 150 x 75 x 34mm, weighs -230 -grams MODEL 2000 $349.95 01.000*: 20 MHz DUAL TRACE OSCILLOSCOPE Model 2000 combines useful features arid exactng quality. Frequency calculation and phase measurement are quick and easy in the X -Y Wide. Service technicians will appreciate the TV Sync circuitry for viewing TV -V and TV -H as well as accuree synchrcni- DPM-1000 $54.95 zation of the Video Signal, Blanking Pedestals. VITS 3..5 DIGI7 PROBE T APE LIMM and Verticle.- Horizontal sync pulses. ALtoranging, pen style deAgn for the uhimate it portability and Lab quality compensated 10X probes ire luded ease cd use. Custom 80 pir LSI chip increases reiability. Audible Built-in component tester continuity tester and data hold featureor added convenience. 110/220 Volt operation Case. test leads and batteries indicted X -Y operation Bright 5" CRT TN. Sync fi ter Basic DC accuracy: plus or minus 1% DC voltage: 2v -500v, autoranging AC voltage: 2s, 500v, autoranging Resistance: 21. ohms 2M ohms. autorarging Fully over -loss protected MODEL 3500 $499.95 2 YEAR Input impedance. 111V ohm 35 MHz DUAL TRACE OSCILLOSCOPE 62 x 28 x 17rnm. weighs 75 grams I=C=3211r7Z.11.:1-MJI Wide bandwidth and exceptional 1mV, Cl" sensitivity WARRANTY - make the Model 3500 a powerful diens:es-tic tool for 1 _I I \4Z,1 engineers or technicians. Delayed triggeri to allows any portion of a waveform to be isolated andpanded for ON ALL

f ') raki, closer inspection. Variable Holdoff make, possible :he

_110. Mt i _ stable viewing of complex waveforms. MODELS lab quality compensated 10X probes me luded

I Delayec and single sweep modes Z Axis intensity modulation X -Y operation Bnght 5" CRT TN. Sync filter 0 -_ ORDER TOLL FREE 41M JDR 110 KnowlesINSTRUMENTSDrive, Los Gatos, CA 95030 800-538-5000 (408) 866-6200 FAX (408) 378-8927 Telex 171-110 OR VISIT OUR RETAIL STORE COPYRIGHT 1986 JDR MICRODEVICES 1256 SOUTH BASCOM AVE. THE JDR INSTRUMENTS LOGO S A REGISTERED TRADEMARK OF JDR M CRODEVIE> JDR 1NSTFUMENTE IS A TRADEMARK OF JOB MICRODEVIC SAN JOSE, CA. (408) 947-8831 CIRCLE 59 ON FREE NFORNIVION CARD WHAT'S NEWS

Travelling robot to work in radiation -hardened IC lab Solar -powered cars to race across Australia The new Radiation Hardened Integrated Circuit (RHIC) facility General Motors is entering a nearing completion at Sandia Na- 1,950 -mile trans -Australia motor tional Laboratories, Albuquerque, race open only to solar -powered NM, will be the first U.S. research cars. The race, scheduled for lab to use a robot in the entire November 1, may attract up to 25 production process. The new entries. It will start from Darwin, robot will travel RHIC's 300 -foot on Australia's north coast, and long clean room's center aisle, ac- finish at Adelaide, on the south cessing 22 specialized processing coast, about six days later. The bays (actually small clean rooms) team with each car must be self- that can be entered from that aisle. sufficient, carrying all its water, Passing the bays, it will home in food, and supplies, and must on selected work -in -progress sta- camp overnight at the end of each tions and pick up the plastic cas- day's driving. settes (small boxes) housed there, The GM car, named the GM Sun- moving them to other processing raycer, runs entirely on storage bays. The robot follows a reflective batteries powered by the car's so- tape track laid on floors through lar system and uses a new high - the 12,500 -foot clean -room area, efficiency motor from GM's labs and constantly receives routing in- that uses low -friction bearings and structions from the facility's com- Magnaquench magnets. A Magna - puterized wafer -fabrication oper- quench magnet is a super- THE MAGNAQUENCH MOTOR to be used in ating system. strength, rare-earth, iron -based the solar -powered car is unusually small. Dr. "Other wafer -fabrication lines permanent magnet that may revo- Nady Boules, section manager at GMRL's have used robots," says a Sandia Electrical and Electronics Engineering Dept., lutionize the field of electronics is holding the motor's rotor in his right hand, spokesman, "but they have been because it makes possible electric and the motor housing in his left. confined to specific work stations. motors having more power, higher The case is the same as that for the energy efficiency, and smaller size A Magnaquench technology highly acclaimed robots that work and weight than motors made high -efficiency electric motor has along modern automobile assem- using conventional technology. been tested at 92% efficiency. bly lines." Standard electric motors of com- Advantages of the new system parable size run at only 75-85% include reduction of pollution efficiency. In practical terms, it possibilities due to greatly re- means that an8 -pound duced human handling and to Magnaquench motor can produce more gentle handling due to spe- two horsepower continuously at cial force -sensing capabilities built 4000 rpm, which is about 30-40% into the robot. The latter makes more horsepower than compara- make sure that the robot is using ble -size presently -available com- the right amount of energy in pick- mercial motors. ing up and setting down the cas- In designing and racing the settes entrusted to it. Sunraycer, GM expects to develop The RHIC is the latest major ad- and demonstrate expertise in sev- dition to Sandia's Center for Radia- eral advanced technologies with tion -Hardened Microelectronics. THE SOLAR -POWERED CAR's spa«.tranm practical automotive applications. The Center designs and builds mi- and chassis gets its first test drive in Califor- nia. Dr. Alec Brooks of AeroVironment, Inc., Those include lightweight struc- crocircuits that continue to oper- is checking its rigidity, handling and suspen- tures and materials, low -speed ate even after receiving high doses sion. The lightweight spaceframe, made of aerodynamics and high -efficiency of radiation for use in nuclear - aluminum tubing, will become a sleek, high- tech racer when covered by its integral body, batteries, electric motors, and so- weapon, space, and satellite ap- canopy and solar panels. lar cells and panels. plications. R -E

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DAVID LACHENBRUCH, CONTRIBUTING EDITOR SVHS and the Multi -Port. A new example, some proposed compatible HDTV compatibility headache may be in the works for systems would transmit standard 525 -line cable, with the introduction of Super VHS pictures on existing channels, using all or part of recorders. Just when the cable industry thought a separate channel for additional information to it had solved its compatibility problems, along make up a picture with more horizontal lines and comes Super VHS (SVHS) which is at least partly a wider aspect ratio. incompatible with the new Multi -Port standard Meanwhile, Home Box Office has started a (Radio -Electronics, April 1987). Multi -Port was campaign to encourage development of HDTV developed over four years by an engineering cable service. Because cable has no shortage of committee representing receiver manufacturers channels, HBO feels that cable has an edge over and cable systems. It involves a 21 -conductor broadcasters in supplying HDTV, because it can connector to be built into future TV sets (a few assign wideband channels for HDTV while already have it) that, in effect, will eliminate the continuing to broadcast standard TV signals over need for external cable -tuning and -decoding other channels. HBO urged cable interests to boxes and make it possible to use a TV set's avoid "the same kind of incompatibility problems remote control system to tune all channels, we as an industry experienced with cable -ready including scrambled ones. The Multi -Port was TV's, connection of VCR's to the cable drop, and also designed to accommodate all TV delivery of...stereo." attachments, including VCR's, videodisc players, and home computers. It includes video and RGB Flickerless 3-D disc. The Japanese are inputs-but not Y and C (luminance and color) relentless in their pursuit of 3-D television. JVC inputs. Although SVHS recorders have video and Sharp both demonstrated 3-D videodiscs outputs, a better picture results from using Y/C recently at the American Consumer Electronics connectors, and new TV sets designed for use Show. That system used electronically controlled with SVHS recorders have special Y/C inputs. The LCD eyeglasses connected to the TV set by a wire. committee that developed the Multi -Port is now The system permitted each eye to see an meeting on the subject of SVHS, and one proposal alternate field of the picture, reducing the is that the RGB input be made optional and number of fields seen by each eye from the replaceable by Y/C. Disgruntled committee normal 60 to 30. The result was that the system members say that if the Japanese had taken a suffered from a pronounced "flicker". more active role in the committee's engineering Now Sanyo and Japan's NHK (Japan work, the problem would never have occurred. Broadcasting Co.) have come up with a new version of the system that eliminates the flicker. FCC looks at HDTV. Responding to requests Based on a laser videodisc, the system uses time by 58 broadcaster groups, the FCC has opened a compression to double the number of fields to 120 "comprehensive inquiry" into advanced per second, letting each eye see 60 cycles, which television systems, particularly High -Definition is above the threshold of flicker. The system TV (HDTV). Among issues to be explored are the maintains full vertical resolution by using 4:1 proposed specifications and characteristics of interlace, letting each eye see a full 525 scanning advanced television systems, timetables, public lines. It also eliminates the wire connection for interest in better television systems, and the the eyeglasses by using an infrared wireless effect on existing TV systems. Because many of system. Of course, all that elaborate engineering the proposals for HDTV require using more than is going to cost. The 3-D disc system, including a the bandwidth of a single present channel, the 30 -inch color monitor, will cost almost $7,000, so FCC has frozen new proposed applications for TV the Japanese believe its first uses will be in channels in 30 of the largest markets. For commercial and industrial applications. R -E NEW! Scanner Frequency ListingsBearcat® 800XLT-RA The new Fox scanner frequency directories will help List price $499.95/CE price $289.95/SPECIAL you find all the action your scanner can listen to. These 12 -Band, 40 Channel No -crystal scanner new listings include police, fire, ambulances & rescue Priority control Search/Scan AC/DC NEW! squads, local government, private police agencies, hospitals, emergency medical channels, news media, Bands: 29. 54, 118-174, 406-512, 806-912 MHz forestry radio service, railroads, weather stations, radio The Unider 800 XLT receives 40 channels in two banks. CB Radios & common carriers, AT&T mobile telephone, utility com- Scans 15 cnannels per second. 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BC 175XL-RA Bearcat 16 channel scanner $156.95 scanners, introduces new models of State of Alaska-RLO19-1; Baltimore, MD/Washington, BC 210XLT-RA Bearcat 40 channel scanner $196.95 DC-RL024-1; Chicago, IL-RL014-1; Cleveland, OH- BC -WA -RA Bearcat Weather Alert' $35.95 CB & marine radios and scanners. RL017-1; Columbus, OH-RL003-2; Dallas/Ft. Worth, R1080 -RA Regency 30 channel scanner $118.95 TX-RL013-1; Denver/Colorado Springs, CO-RL027-1; R1090 -RA Regency 45 channel scanner $148.95 NEW! Regencyi TS2-RA Detroit, MI/ Windsor, ON-RL008-2; Fort Wayne, IN UC102-RA Regency VHF 2 ch. 1 Watt transceiver ...$117.95 Allow 30-90 days for delivery after receipt of order /Lima, OH- RL001-1; Houston, TX-RL023.1; Indian- P1412 -RA Regency 12 amp reg. power supply... $189.95 due to the high demand for this product. apolis, IN-RL022-1; Kansas City, MO/ KS-RL011-2; MA549- RA Drop -in charger for H X12008. 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A regional directory 8 -4 -RA 1.2 V AAA NI -Cad batteries (set of four) $9.95 Game, Immigration, Marine, Police and Fire Depart- which covers police, fire ambulance & rescue squads, 8 -8 -RA 1.2 V AA Ni-Cad batteries (set of eight) $17.95 ments, Aeronautical AM band, Paramedics, Am- local government, forestry, marine radio, mobile phone, F8- E -RA Frequency Directory for Eastern U.S.A. $14.95 ateur Radio, plus thousands of other radio fre- aircraft and NOAA weather is available for $19.95 each. FB-W-RA Frequency Directory for Western U.S.A $14.95 quencies most scanners can't pick up. The Regency RD001-1 covers AL, AR, FL, GA, LA, MS, NC, PR, SC, TN ASCSRA Air Scan Directory $14.95 TS2 features new 40 channel per second Turbo & VI. For an area not shown above call Fox at 800-543- SRF-RA Survival Radio Frequency Directory $14.95 7892 or in Ohio 800-621-2513. Scan" so you wont miss any of the action. Model TSG-RA"Too Secret" Registry of U.S. Govt. Freq. $14.95 TS1-RA is a 35 channel version of this radio without Regency° Informant' Scanners TIC -RA Techniques for Intercepting Comm. $14.95 the 800 MHz. band and costs only $239.95. Frequency coverage: 35-54, 136-174 406-512 MHz. RRF-RA Ra road frequency directory $14.95 The new Regency Informant scanners cover virtu- EEC -RA Embassy& Espionage Communications $14.95 Regency° Z60 -RA ally all the standard police, fire, emergency and CIE -RA Covert Intelligenct, Elect. Eavesdropping 514.95 List price $299.95/CE price $148.95/SPECIAL weather frequencies. These special scanners are MFF-RA Midwest Federal Frequency directory . $14.95 8 -Band, 00 Channel No -crystal scanner preprogrammed by state in the units memory. Just A60 -RA Magnet mount mobile scanner antenna... $35.95 Bands: 30-50, 88-108,118-136, 144-174, 440-512 MHz. pick a state and a category. The Informant does the A70 -RA Bate station scanner antenna $35.95 The Regency Z60 covers all the public service rest. All Informant radios havefeature called MA548-RA Mirror mount Informant antenna $39.95 bands plus aircraft and FM music for a total of Turbo Scan" to scan up to40 channels per second. USAMM-RA Mag mount VHF ant. w/ 12' cable $39.95 eight bands. The Z60 also features an alarm The I N F1 -RA is ideal for truckers and is only USAK-RA 3/4- hole mount VHF ant. w/ 17' cable.... $35.95 clock and priority control as well as AC/DC $249.95. The new IN F2 -RA is a deluxe model and Add $3.00 shipping for all accessories ordered at the same time. operation. Order today. has ham radio, a weather alert and other exciting Add $12.00 shipping per shortwave receiver. features built in for only $324.95. For base station Add $7.00 shipping per radio and $3.00 per antenna. Regency° Z45 -RA use, the IN F5 -RA is only $199.95 and for those BUY WITH CONFIDENCE List price $259.95/CE price $139.95/SPECIAL who can afford the best, the IN F3 -RA at $249.95, is To get the fastest delivery 7 -Band, 45 Channel No -crystal scanner a state-of-the-art, receiver that spells out what send or phone your order directly to our Scanner Bands: 30-50, 118-136, 144-174, 440-512 MHz. service you're listining to such as Military, Airphone, Distribution Center" Michigan residents please add 4% The Regency Z45 is very similar to the Z60 model Paging, State Police, Coast Guard or Press. sales tax cr supply your tax I.D. number. Written pur- listed above however it does not have the commer- chase orders are accepted from approved government cial FM broadcast band. The Z45, now at a Regency° HX1500-RA agencies aid most well rated firms at a 10% surcharge special price from Communications Electronics. List price $369.95/CE price $218.95 for net 10 billing. All sales are subject to availability, 11 -Band, 55 Channel Handheld/Portable acceptance and verification. All sales on accessories Search Lockout Priority Bank Select are final. Prices, terms and specifications are subject to Regency° RH256B-RA Sidelit liquid crystal display EAROM Memory change without notice. All prices are in U.S. dollars. Out List price.$799.95/CE price $329.95/SPECIAL Direct Channel Access Feature Scan delay of stock itemswill be placed on backorder automatically 16 Channel 25 Watt Transceiver Priority Bands: 29-54, 118.136, 144.174, 406-420, 440-512 MHz. unless CE is instructed differently. A $5.00 additional The Regency RH256B is a sixteen -channel VHF land The new handheld Regency HX1500 scanner is handling fee will be charged for all orders with a mobile transceiver designed to cover any frequency fully keyboard programmable for the ultimate in merchandise total under $50.00. Shipments are F.O.B. between 150 to 162 MHz. Since this radio is versatility. You can scan up to 55 channels at the Ann Arbor, Michigan. No COD's. Most products that we synthesized, no expensive crystals are needed to same time including the AM aircraft band. The LCD sell have a manufacturer's warranty. Free copies of store up to 16 frequencies without battery backup. display is even sidelit for night use. Includes belt warranties on these products are available prior to All radios come with CTCSS tone and scanning purchase by writing to CE. Non -certified checks require clip, flexible antenna and earphone. Operates on 8 bank clearance. Not responsible for typographical errors. capabilities. A monitor and night/day switch is also 1.2 Volt rechargeable Ni-cad batteries(not included). standard. This transceiver even has a priority func- Be sure to order batteries and battery charger from Mailorders to:Communications Electron- tion. The RH256 makes an ideal radiof or any police the accessory list in this ad. ics7 Box 1045, Ann Arbor, Michigan 48106 or fire department volunteer because of its low cost U.S.A. Add $7.00 per scanner for R.P.S./U.P.S. and high performance. A 60 Watt VHF 150-162 Bea rcar 100XL-RA ground shipping and handling in the continental MHz. version called the RH806B-RA is available List price $349.95/CE price $178.95/SPECIAL U.S.A. For Canada, Puerto Rico, Hawaii, Alaska, for $459.95. A UHF 15 watt, 10 channel version of 9 -Band, 16 Channel Priority Scan Delay or APO/FPO delivery, shipping charges are this radio called the RU150B-RA is also available Search Limit Hold Lockout AC/DC three times continental U.S. rates. If you have a and covers 450-482 MHz. but the cost is $439.95. Frequency range: 30-50, 118-174, 406-512 MHz. Discover, Visa or Master Card, you may call and Included in our low CE price is a sturdy carrying case, place a credit card order. Order toll -free in the Bearcat° 50XL-RA earphone, battery charger/AC adapter, six AA ni-cad U.S. Dial 800 -USA -SCAN. In Canada, order toll - List price $199.95/CE price $114.95/SPECIAL batteriesand flexible antenna. Order your scanner now. 10 -Band, 10 Channel Handheld scanner free by calling 800-221-3475. FTCC Telex any- Bands: 29.7-54, 136-174, 406-512 MHz. ** * Uniden CB Radios *** time, dial 825333. If you are outside the U.S. The Uniden Bearcat 50XL is an economical, hand- The Uniden line of Citizens Band Radio transceivers is or in Michigan dia1313-973-8888. Order today. held scanner with 10 channels covering ten fre- styled to compliment other mobile audio equipment. Scanner Distribution Center' and CE logos are trade- quency bands. It features a keyboard lock switch to Uniden CB radios are so reliable that they have a two marks of Communications Electronics Inc. prevent accidental entry and more. Also order the year limited warranty. From the feature packed PRO Bearcat is a registered trademark of Uniden Corporation. new double -long life rechargeable battery pack 540e to the 310e handheld, there is no better Citizens Regency and Turbo Scan are registered trademarks of part # BP55 for $29.95, a plug-in wall charger, part Band radio of the market today. Regency Electronics Inc. AD *080187 -RA # AD100 for $14.95, a carrying case part # VC001 PRO310E-RA Uniden 40 Ch. Portable/Mobile CB... $85.95 Copyright c 1987 Communications Electronics Inc. N I NJA- RA PRO310E with rechargeable battery pack.$99.95 for $14.95 and also order optional cigarette lighter B -10 -RA' 2V AA Ni-cad bait. for Ninja (set of 10) ....$20.95 cable part # PS001 for $14.95. PRO520E-RA Uniden 40 channel CB Mobile $59.95 For credit card orders call PRO540E-RA Uniden 40 channel CB Mobile $119.95 PRO710E-RA Uniden40 channel CB Base $119.95 PC22-RA Uniden remote mount CB Mobile $99.95 1 -800 -USA -SCAN PC55-RA Unidenmobile mount CB transceiver $59.95 ** * Uniden Marine Radios* * * Now the finest marine electronics are availab:e through CEI. The Unimetrics WM-RA has 50 transmit and 60 COMMUNICATIONS receive frequencies with 25 or 1 watt power output. Only $169.95. The Unimetrics SH 88 -RA is a deluxe full function marine radiotelephone featuring 55 transmit ELECTRONICS INC. and 90 receive channels and scanning capability for only $259.95. The Unimetrics SH3000-RA is an excel- Consumer Products Division lent digital depth sounder, good for 300 feet. It has an P.O.Box 1045 O Ann Arbor, Michigan 48106-1045 U.S.A. LCD continuously backlit with red light display and a 5 Ca11800-USA-SCAN or outside U.S.A. 313-973-8888 ft. or 10 ft. alarm. Only $189.95. Order today. CIRCLE 79 ON FREE INFORMATION CARD LETTERS LETTERS R4D/o- ELECTRON/CS 500-B B/- COUNTY BOULEVARD FARN1/NGDALE, NY /1735

LASER LISTENER LEGALITIES tightly regulated by both federal der this statute, the assembly, pos- The lead paragraph of your Oc- and state statutes. Severe penal- session and use of the Radio - tober cover story ("Build This Laser ties, including jail terms longer Electronics laser listening device is Listener") warns that "Breaking than those for breaking and enter- clearly illegal, because the device and entering to plant a listening ing, are specified for violators. is presented solely as a means device...can earn someone a long The federal statute prohibits the "...to listen in to anything, any- jail term." You then suggest that "A manufacture, assembly, posses- where, any time." better and safer way to bug a room sion, sale, and transport across Your article warned of the pos- is to use a laser beam to eavesdrop state lines of devices whose pri- sibility of "....eye damage if some- on a window from across the mary purpose is the unauthorized one in the target area unknowingly street." interception of wire or oral com- stares into the beam...." Yet the This suggestion is a serious dis- munication (U.S. Code, Title 18, cover photo shows a laser pointed service to your readers, for elec- Chap. 119). Willful violators of this very close to the faces of two peo- tronic eavesdropping of all kinds, statute may be fined up to $10,000 ple behind a window, and the including laser eavesdropping, is and imprisoned up to 5 years. Un- opening paragraph states that

With a Huntron TiackeL How do you troubleshoot a cold circuit board down to the component level? Without power to the board, finding the bugs can be tough. So when conventional testing is out, call in a Tracker. CATCH BUGS Portable or benchtop. With our portable, field service Trackers, and now our new bench -top Tracker 5000, you have everything you need for isolating defective analog, digital, and hybrid circuit boards. COLD. Meet the family: Tracker 5000-Apowerful, menu -driven, automated, benchtop troubleshooting system controlled by an IBM PC, or compatible. Now you can develop test procedures for particular boards, store them in a library and call them up whenever you need them. Tracker 5000 speeds up testing of older or less common boards. Tracker 1000 & 2000-Theperfect companions to your test equipment arsenal. Both offer in -circuit testing with the power off. In addition, the Tracker 2000 can dynamically test a wider range of devices. Find out more. Call toll free: 1-800-426-9265 or contact Huntron Instruments, Inc.15720 Mill Creek Blvd., Mill Creek, WA 98012. Phone 206-743-3171. Telex 152951.

CIRCLE 219 ON FREE INFORMATION CARD 1-IUNtRON 8 Call 1-800-843-3338 today laser eavesdropping is "better and safer" than conventional elec- to start thoroughly analyzing tronic bugging. My personal experience with and pinpointing any trouble in any laser eavesdropping technology, which is neither high-tech nor TV-RF distribution system, new, is not unblemished. In "Sil- automatically to FCC specifications... iconnections: Coming of Age in the Electronic Era" (McGraw-Hill, 1986), a memoir about some of my experiences as an electronics writ- er, I wrote about a 1976 assignment ti...-el-ammisar _ma I received from a newspaper to use - hi F.( 0.r.E Vta an infrared laser and receiver to 12 0.000 intercept the conversations of Howard Hughes at his hotel in the MACY Bahamas. Fortunately Hughes left for Mexico shortly before I was to INIMIVOC>PME 1000.1.6,11 leave for the Bahamas. The paper cwaroaLue11. had convinced me Hughes's con- TV AP WOK. ANALYSIII versations might reveal possibly il- All legal conduct. They failed to warn IIMM tree.. re Iwo. me that laser eavesdropping is in 41. itself illegal. -a= a In 1985 I prepared a report on laser eavesdropping for the Senate Select Committee on Intelligence in whichI warned of the vul- with the All New < IEEE -488> nerability of government installa- FS74 CHANNELIZER SR.TM TV-RF Signal Analyzer tions to that technology. Since Patents Pending $3495 then I have written several articles and papers that discuss the tech- Does your success in servicing RF distribution systems depend on locating problems quickly and accurately? If so, here's why your all new Sencore FS74 nical, legal, and safety aspects of CHANNELIZER SR. will mean success for you ... laser eavesdropping as well as possible countermeasures. None of Quickly tune in all TV/FM channels from 5 MHz to 890 MHz. Exclusive all those articles included con- channel, microprocessor -controlled digital tuner checks every standard and struction details. I have also dem- cable channel with better than FCC accuracy to fully analyze any system. onstrated laser eavesdropping and Exclusive 5 microvolt sensitivity to bring in even weak signals. Autoranged discussed some of those same is- attenuator automatically selects the best sensitivity for simplifying your sues in several television inter- VHF, UHF, or FM signal measurements like never before possible. views and a documentary film. Automatic hassle -free SIN ratio, A/V ratio, and hum level tests. Exclusive on - In short, I believe it is important channel signal-to-noise ratio test eliminates time-consuming signal for private citizens, businesses, comparison and chart reading. Exclusive audio -to -video ratio test measures and government to be informed directly in dB for easy comparison to specifications. about electronic eavesdropping technology. But I believe it was a Exclusive checks for ghosts, co -channel interference, line reflections, and other signal quality checks. Portable 4 MHz wideband battery -operated monitor lets serious misjudgment for Radio - you finally check the quality of your cable or MATV system and stop Electronics to have published de- annoying callbacks. tailed construction plans for an illegal eavesdropping device and to Built-in autoranging AC/DC volt/ohmmeter makes troubleshooting a snap. have encouraged its readers to Exclusive all-weather design holds tighter than FCC specifications from -4 °F build and use it. to +104 °F. Truly portable, field-tested tough for dependable ease of use. FORREST M. MIMS, Ill Begin successfully locating TV-RF signal problems more quickly and accurately than ever before possible, with the new FS74 CHANNELIZER "DREAMS OF RIO" SR. Call WATS Free 1-800-843-3338 today for a free Product Guide or an I think the readers of Radio -Elec- industry exclusive "Try before you buy" 15 Day Self Demo. tronics will be interested in ZBS "CHANNELIZERSR.- is a trademark of Sencore. Inc. Productions' latest audio adventure program, "Dreams of Rio." WATSFree1-800-843-3338 WICanada WATSFree1-800-851-8866 The 13 -week series recreates the magic of old-time radio drama, 111C4C:)1=1 using state-of-the-art digital recording techniques to capture the Means Success In Electronic Servicing sounds of Brazil. The plot takes 3200 Sencore Drive, Slow. Falls. South Dakota 57107 Call Collect 605-339-0100In SO & AK CIRCLE 177 ON FREE INFORMATION CARD 9 hero Jack Flanders and his an- The half-hour shows will be WA), KUER(Salt Lake City, UT), thropologist girlfriend, Frieda, aired weekly over National Public KQED(San Francisco, CA), KBOO from the night clubs of Rio, Radio beginning in September. (Portland, OR), KCRF (Denver, through the Brazilian jungles to (Please check local listings, or con- CO), KUNM (Albuquerque, NM), find the "Lost City." Producer/writ- tact your local NPR station, for ex- KMUW (Wichita, KA), KPBS(San er Tom Lopez and composer Tim act dates and times.) Some of the Diego, CA), and KUAC (Fairbanks, Clark spent a month on location, major stations that will be airing AK). recording ambient sounds using the shows are: WJCT (Jacksonville, I'm sure the series will appeal to Sennheiser 416 and Tram micro- FL), WLRN(Miami, FL), WCBU fans of old-time radio, as well as phones along with Sony's PCM-F1 (Louisville, KY), WVOM (Ann Ar- anyone interested in the latest in digital tape recorder. The high - bor, MI), WCMU (Mt. Pleasant, audio technology. quality recordings bring the MI), WNYC (New York, NY), KATHY GRONAU characters to life, and make the WOUB (Athens, OH), KCRW (San- ZBS Foundation listeners feel as if they're in Brazil. ta Monica, CA), KOUW (Seattle, Fort Edward, NY 12828

SCA ERRORS I noticed a few errors and discre- CABLE TV pancies in the SCA receiver's parts layout ("Build This SCA Receiver, SPECIALS Part 2", September 1987): Diode D5 is shown backwards. No polar- CONVERTERS ity is shown for C59; the upper end is the positive one. Capacitor JRX-3 DIC-6 Channel Corded Remote s139.95 C29 is shown twice; the one near JSX-3 DIC-36 Channel Set Top Si29.95 FL3 is really C24. Also, the correct SB-3 - 'The Real Thing' 5109.95 C29 is shown backwards. The base SB-M-Refurbished S89.95 and collector leads for Q7 are misi- dentified; swap them and then DRZ-3D1C-68 Channel Wireless move the connection from S2 to with Decoder Si 99.95 the unused hole that's approx- ZENITH: Z-TAC Cable Add -On '199.'6 imately 1/4 -inch northeast of Q7. Switch S2 shows a wiring error: VIEW STAR: EVSC- 2010-60 Channel Wireless- Remove the connection between with Parental Lockout 1 99.11 pin 1 of the left-hand gang and the line to C59 and add a connection EVSC-2010 A -B -Same as above with between pin 1 of the center gang A -B Switch '109." and the line to J5. View Star 2501 -60 Channel Wireless Going back to Part 1 of the arti- with Volume '119." cle, there is a missing dot in the Unika MR -702-72 Channel Wireless schematic at the junction of C25, with Parental Lockout s89.95 C26, R33, and pin 3 of IC1. MISCELLANEOUS G.L. McDONALD Auburn, WA OAK: N-12 Mini -Code 89." ON TESTING ERRORS 599.95 N-12 MInI-Code Varl-Sync In his letter, "Testing Semicon- N-12 Minl-Code Vari-Sync Plus Auto On -Off s159.95 ductors" ("Letters", August 1987) Richard P. Morley is correct in as- JERROLD: 400 & 450 Handheld Transmitters ' 29." suming that the voltmeter will have an affect on the indicated HAMLIN: MLD-1200 99.11 leakage current of the diode under test. If we connect a standard 10- NEW ITEMS:Ripe Tape Copy Stabilizer $109.95 megohm voltmeter across that circuit, it will draw 10 µ,A at 100 volts, which is the maximum leakage Scientific Atlanta SA -3 Si 39.95 current specified for a 1N4000 -series diode. In that situation, it OAK: E-13 Mini -Code Substitute 79,95 would be much better to place the E-13 Mini -Code W/Vari-Syn 89.95 current meter on the other side of the voltmeter. AU UNITS GUARANTEED. QUANTITY PRICES AVAILABLE. Unfortunately, low -current am- meters tend to have very high in- UNITED ELECTRONIC SUPPLY ternal resistance. Consequently, the voltage indicated by the volt - P.O. BOX 1206 ELGIN, ILLINOIS 60121 312-697-0600 10 CIRCLE 207 ON FREE INFORMATION CARD Analyze defective waveforms meter in the new configuration is not a true value; that is because faster, more accurately, and the actual voltage across the time meter/diode combination adds up more confidently - every to more than the voltage across the or your moneyback diode under test-meaning that the diode is receiving less voltage than indicated. Should the leakage current be on the order of 1-mA (not uncommon), for example, then the voltage drop across a 2000 -ohm milliameter will be two volts. Two volts may not seem like much, but at 10 volts it is a 20% error. Depend- ing on the voltage and the current values involved, current -meter resistance can (and does) affect the measurement in your alternate configuration to the same extent that a parallel voltmeter may affect measurements in other situations. The issue of voltmeter loading was discussed at length in Part 1 of the "Testing Semiconductor" series (Radio -Electronics, February with the SC61 Waveform Analyzer 1987, page 60), and remedies were Patented $2,995 recommended. Irealize that not all technicians take the time to If you value your precioustime, youwill really want to check evaluate the situation properly, out what the exclusively patented SC61 Waveform Analyzer can and the problem of inaccurate test do for you. 10 times faster, 10timesmore accurate, with zero procedure cannot be over- chance of error. emphasized. My thanks to Mr. End frustrating fiddling with confusing controls. Exclusive ultra solid Morley for bringing it to our read- ECL balanced noise cancelling sync amplifiers, simplified controls, and ers' attention one more time. bright blue dual trace CRT help you measure signals to 100 MHz easier TJ BYERS than ever. Accurately and confidently measure waveforms from a tiny 5 mV MAKING PC BOARDS I am writing to share with your all the way to a whopping 3,000 V without hesitation with patented 3,000 VPP input protection - eliminates expensive "front end" repairs other readers a technique that I discovered for using a Xerox cop- and costly equipment downtime. ier to make printed -circuit boards. Make only one circuit connection and push one button for each I suspect that there are many hob- circuit parameter test: You can instantly read out DC volts, peak -to -peak byists who would like to etch PC volts and frequency 10O') automatically with digital speed and accuracy. boards but, like me, have no ac- It's a real troubleshooting confidence builder. cess to a darkroom or the pho- Confidently analyze complex waveforms fast and easily. Exclusive toresist chemicals, but do have Delta measurements let you intensify any waveform portion. Analyze use of a Xerox machine. The tech- glitches, interference signals, rise or fall times or voltage equivalents be- nique that I worked out for trans- tween levels; direct in frequency or microseconds. ferring the layout image onto a copper -clad board is very simple; Speed your digital logic circuit testing. Analyzing troublesome divide itis also fast, and it yields near - and multiply stages is quicker and error free - no time-consuming professional results. graticule counting or calculations. Simply connect one test lead to any test The artwork is prepared as de- point, push a button, for test of your choice, for ERROR FREE results. scribed in your series "Etch Your To see what the SC61 can do for your troubleshooting personal productivity Own PC Board" (Radio -Electronics, and analyzing confidence, CALL TODAY, WATS FREE, 1-800-843-3338, December 1982 through February for a FREE 15 day Self Demo. 1983) and then copied onto a Xerox transparency-the type used to Call Today Wats Free 1-800-843-3338 make overhead projector slides; the contrast should be set for as 9 rVCC::01=t dark as possible in order to get the 3200Sencore Drive heaviest possible coating of the Sioux Falls, SD 57107 innovatively designed toner. It is useful to make more 605-339-0100 In SD Only with your time in mind. CIRCLE 178 ON FREE INFORMATION CARD 11 than one transparency in case the on top. That image can be re- tached along only one edge with first transfer does not come out. mobilized by again heating it to tape, so that it can easily be peeled The PC blank is prepared simply about 300°F.I do that using a off when done, without damaging by buffing the copper with fine household clothes iron. the delicate image. While the cop- steel wool to remove oxidation The iron is secured by clamps in per comes up to heat, roll the film and contaminants. The image on a inverted position, so that its hot against the copper to transfer the the transparency is transferred by sole can be used as a work area. image. (I used a 1" wallpaper heat. When a Xerox copy is made, The iron is then brought to tem- roller.) As the toner melts, the film a black powder called "toner" is perature for a moderately high set- adheres to the copper, and after a deposited on the page and then ting ("wool"). Then the copper minute or two, the entire image heated to 300°F to fuse it in place. blank is heated from the back, with should be stuck down. Then, On paper, the fused toner is ab- the transparency secured to the while the copper is still hot, care- sorbed into the porous surface, foil with its toner -side against the fully peel the transparency off and but on plastic film it just builds up copper. The transparency is at - let the board cool. A mirror image of the layout should be affixed, in complete detail, to the copper. Your Career in ELECTRONICSor COMPUTERS If the results at that point are not completely satisfactory, there are two options. If there are only a few Put Professional Knowledge and a Grantham College of Engineering is minor imperfections, they can be a specializedinstitution catering to touched up with a very fine felt-tip COLLEGE DEGREEmature individuals who are employed pen. Otherwise, the image can be in your Technical Careerthrough in electronics and allied fields such as cleaned off and the copper re -buf- HOME computers. These fields are so enor- fed for another attempt with a L:111. mous that advancement opportunity fresh transparency. It is so quick isalwayspresent. Promotions and and easy to transfer an image that

STUDY . natural turn -over make desirable posi- it is worth while to make a couple Awpal , tions available to those who arepre- of practice runs in order to get a Aimfriikr.d pared to move up! feel for the process. Once a satis- ai Advancement in your career is made factory mask is transferred, the easier and more certain by (1) superior board may be etched. knowledge and (2) documentation of I was amazed at how good the that knowledge - both of which are results were: My very first attempt No commuting to class. Study at your obtainable through Grantham distance produced a slightly flawed but own pace, while you continue on education, fully accredited by NHSC. workable board. After modifying your present job. Learn from easy -to - Grantham's home study (distance ed- my methods, all subsequent runs understand lessons, with help fromucation) programs leading to the have been totally successful. your instructors when you need it. I have never used the photo - transfer method, so I cannot com- Grantham offers two B.S. degree pro- B. S. DEGREE pare it first-hand to my xerox tech- grams - one with major emphasis in may fill an important need for you. nique.I suspect that the pho- ELECTRONICS and the other with These are comprehensive correspond- tographic method is capable of major emphasisin COMPUTERS. ence programs in which you first review Either program can be completed by producing slightly sharper detail some things you already know, in and higher -density resist. (Minor correspondence (also known as "dis- preparation for the studies that come pitting occurs on some of the tance education"), NHSC accredited. later. Some previous knowledge in The sooner you get started, the sooner traces, but so far that has not inter- electronicsis presumed, but is thor- fered with any circuit.) you can be ready to benefit from greater oughly reviewed in depth, so as to give knowledge and your B.S. degree. There are several definite advan- you a thorough foundation for the tages to the Xerox process: Fore- Our free catalog gives full details of level of studies you have not previously most is that almost everyone has both degree programs. For your copy undertaken. Even though some stu- access to a Xerox copier, either at of the free catalog write to the address dents hold associate degrees before en- work or through commercial copy- shown below, or phone (213) 493-4422 rolling, an A. S. Degreeisawarded ing services. The resist mask is to- (no collect calls); ask for Catalogl 1-87. along the way toward the B. S. Degree. tally visible on the copper blank, so that touch-ups can be made For full information, write for Catalog 11-87. right on the copier, if needed. The process automatically transfers a Grantham College of Engineering mirror image. For work with single -sided boards, that is a definite 10570 Humbolt Street plus. (It is not as useful for double - sided boards, and adjustment P. 0. Box 539 must be made for those.) And, finally, it is a great saving in time and Los Alamitos, California 90720 expense. An existing layout can be 12 Walk "Tough Dog" Troubles Out transferred and etched onto a board, ready for drilling, in well Of Any TV & VCR In Half under an hour for the cost of only ... a few Xerox copies. The Time Guaranteed! So far,I have made only single - sided boards; I intend to try double -sided boards in the near future. I expect to etch each side separately, protecting one side with adhesive -backed film while working on the other. C. BRUCE SNOW Lafayette, LA

FOLLOW-UP As a follow-up to "Build This Digital Tachometer for you Car" and "Build This Digital Speed- ometer for your Car", which were published in the June and July1987 issues ofRadio -Electronics, Iwould like to note a few minor correc- tions that may help any readers who are building those projects. with the exclusive, patented First, in the digital -tachometer VA62 Universal Video AnalyzerTM...$3,495 article, D2 and D4 on the parts - placement diagram should be in- Would you like to ... terchanged, and so should D5 and D6. The 10-µF capacitor labeled Reduce your analyzing time? Isolate any problem to one stage in any TV or VCR in minutes, without breaking a circuit connection, using the tried and proven C14 on the schematic is C4. signal substitution method of troubleshooting. In the digital -speedometer article, the schematic reference to IC5 Cut costly callbacks and increase customer referrals by completely performance should be labeled 4001 instead of testing TVs and VCRs before they leave your shop? Own the only analyzer that 4011. The pick-up coil input should equips you to check all standard and cable channels with digital accuracy . Check read P1 not P2. Also on the sche- complete, RF, IF, video and chroma response of any chassis in minutes without matic, C12, a 0.1-1,1 bypass capaci- taking the back off the receiver or removing chassis, plus set traps dynamically tor, was omitted. Getting on to the and easily right on the CRT. parts -placement diagram, the set Reduce costly inventory from stocking yokes, flybacks, and other coils and of pads between S1 and IC6 should transformers for substitution only, with the patented Ringing Test? Run be labeled C7. dynamic proof positive test on any yoke, flyback, and integrated high voltage Because of the exceptional re- transformer. sponse to the digital tachometer and digital speedometer, and a sig- Protect your future by servicing VCRs for your customers before they go to your nificant number of request for competition? Walk out "tough dog" troubles in any VCR chrominance or kits, Dakota Digital (R.R. 1, Box 83, luminance circuit to isolate problems in minutes. Have proof positive tests of the Canisota, SD 57012) has expanded video record/play heads before you replace the entire mechanism . its product line as follows: Have one piece of test equipment that doesn't need replacing every time For the digital tachometer: Dis- technology changes? Be able to service Stereo TVs & VCRs profitably, and get in play board (#430103), $6.95; main on the ground floor of this growing market with exclusive phase -locked board (#430104), $12.95; parts kit accessories . (#2002 -KIT), $75.00; Assembled and tested (#3002 -UNIT), $99.95. Find out how the VA62 Universal Video analyzer will make servicing easier For the digital speedometer: and more profitable in your shop? Call WATS Free 1-800-843-3338 and ask display board (#430105), $6.95; your area Sales Engineer for a "Try before you buy" 10 Day Self Demo or a main board (#430106), $12.95; full color brochure and join the many servicers already on the road to more pick-up coil (#2701278), $11.95; profitable servicing with the VA62. magnet set (4) (#2701279), $4.95; Universal Video Analyzer is a trEdemark of Sencore. Inc parts kit (#2004 -KIT), $75.00; assembled and tested unit (#3004 - WATS Free 1-800-843-3338In Canada WATS Free 1-800-851-8866 UNIT), $99.95. Add 5% shipping and handling to all orders. South Dakota resi- 11CC:)1=1 dents must add 5% sales tax. Means Success In Electronic Servicing ROSS ORTMAN R -E 3200 Sencore Drive, Sioux Falls, South Dakota 57107 Call Collect 605-339-0100In SD & AK CIRCLE 179 ON FREE INFORMATION CARD EQUIPMENT REPORTS

ducing pictures rivaling pho- tographic prints, the washed-out PATTERN GENERATOR colors, blended color -bar edges, and the color smear of many rain- NCM MODEL 871 bow generators makes it almost :1411.111111111,07. impossible to determine whether A true NTSC audio/video modern TV's, VCR's, and comput- pattern generator ers are delivering a high-performance picture. That's why we can CIRCLE 20 ON FREE INFORMATION CARD justify reviewing the NCM Elec- tronics model 871 Video Wonder - box: a TV pattern generator that CONTRARY TO WHAT CONSUMER MAG- now call "TV pattern generators." costs $519.00. azines often claim, in real life you The conventional rainbow color - get what you pay for. Buy junk and bar generator was just fine as long Professional quality you get junk, only you don't know as the TV's and VCR's themselves The Video Wonderbox is a true it until you get a chance to experi- were no great shakes at reproduc- NTSC color generator, which ence "quality." That holds true ing color. But now that we have means that its output signal is the when it comes to color -bar gener- digital TV's, HQ VCR's, and com- same one that's used by the TV ators-test equipment that we puter monitors, all capable of pro- networks and stations to test and

3M's new expanded line of A P Products' brand ACE Board 100 Series solderless breadboards offer durability that can't be beat. Why gamble with imports when you can Electronic Specialty Products. Why have the absolute reliability of an ACE gamble with imports? You just can't (All Circuit Evaluator) Board 100 Series ACE Board we make. They're con- lose when you're holding all the ACE's. solderless breadboard from 3M? We've sistently reliable time after time, design For more information contact your local made it easier for you to design, proto- after design, contact to contact. No authorized Electronic Specialty Prod- type and test electronic circuits by pro- import can make this claim. ucts distributor. Call 800-321-9668, or viding the most reliable, durable and ACE Board 100 series breadboards (216) 354-2101 in Ohio to find the name practical base from which to start. are now available in five sizes, all with and location of your nearest dealer. You can bet we'll stand behind every the durability you've come to expect fro n We Solve Problems. Electronic Specialty Products 3M Associated Electronics Department CIRCLE 76 ON FREE INFORMATION CARD

14 9325 Progress Parkway, P.O. Box 540 Mentor, Ohio 44060 3M Discover How The World's Only align their recording and broadcasting equipment. Typical of pro- 100% Automatic, Dynamic, & Portable fessional gear, the Video Wonder - LC Analyzer Gives You Total Confidence box features several specialized outputs. First, there's a con- In Your Cap/Coil Testing... ventional 75 -ohm video output with a switchable peak -to -peak Call 1-800-843-3338 Today! output level of 0.5-, 1.0-, and 1.5 - volts. Then there's an NTSC composite (V andH)TTL-level sync output, a conventional 9 -pin D - connector RGB TTL-level output for testing computer and "universal" TV monitors, and finally, an RF -SEENCCDFREE AUTOZ CAPACITOR INDUCTOR ANALYZER output having a nominal output level of 5 mV into 75 ohms, with an TEST output attenuator with a range of COMPONENT TYPE ,m/VIMA TEA 0-20 dB. EIE 17000 Notice that we didn't refer to a "conventional" RF output. That's EE1 OH II because it's anything but con- 17371 fLCIS111 EC1 AWARNING: ini onsinoneal DO./110 lay ventional. Instead of having an RF lerackaa finnan SM. plenen8 000 iro test loa0a ligh111 ODno, nId...Um.in hand Outing output on Channels 3 and 4 (or 2 esi and 3), the Video Wonderbox's output frequency can be tuned via a front -panel vernier control to any channel in the switch -selected bands of Channels 2-5, 7-13, and LC77 AUTO-rm 14-40. If you suspect that the rea- Automatic Capacitor and Inductor Analyzer son a TV has deficient color on Double Patented $1,895 IEEE - 488/ only one or a few channels might be poor front-end alignment or in- The first cap/coil analyzer guaranteed to reliably test anywhere, without ternally generated spud, you can calculations, look -up tables, or error - 100% automatically so you're confident set the Video Wonderbox right to of your accuracy. the troublesome channel. In that Do you want to eliminate doubt from your cap/coil testing? The LC77 AUTO -Z way, at the very least you can be tests all key parameters with results anyone can understand. Automatic certain that you're working with a good/bad results eliminate the guesswork for error -free analysis. Touch - trouble -free input signal. sensitive keypad and one -two -three setup makes your AUTO -Z the easiest and Because it's often necessary to fastest LC analyzer on the market. make intercarrier checks and ad- Are you frustrated trying to test the new high-tech caps/coils used in modern justments, the RF output has a 4.5 - electronics? Only the LC77 AUTO -Z allows you to test them all. Test capa- MHz sound intercarrier that can citors from 1 pf to 20 farads, with leakage tests to 1000 V and ESR to 2000 be 100% modulated (25 -kHz devia- ohms for locating failures other testers miss. Inductor value from 1 uh to 20 H tion) at 1000 Hz. The ratio of video and a patented ringing test for dependable, error -free coil testing every time. and sound carriers is fixed at 10:1. Do you need the freedom of a battery -operated portable LC meter? The LC77 The video, RF, and RGB test sig- is 100% battery portable for use in the field or factory. The full power and nals are switch -selected. They are: potential of the LC77 AUTO -Z is packed into a light -weight, portable package. 8 x 14 B&W video checkerboard The AUTO -Z puts the complicated electronics on the inside for ease of 19V x 15H B&W crosshatch operation on the outside. 10V x 8H B&W crosshatch with Do you want maximum efficiency with a bus compatible LC testing system? centered dots Your LC77 AUTO -Z is IEEE 488 compatible for automated cap/coil analysis Line and field squarewave. (Top for data collection, incoming inspection, and quality assurance tests. half of frame B&W; bottom half W&B.) Be satisfied that you can meet all the challenges new technology brings. Call WATS Free 1-800-843-3338 today and tell your Area Sales Engineer you want White field to "try before you buy" with Sencore's exclusive 10 Day Self Demo. Black field (at blanking level). Red field AUTO -Z is a trademark of Sencore, Inc. 8 Vertical color bars (plus max- WATS Free 1-800-843-3338 imum screen brightness for 9 In Canada WATS Free 1-800-851-8866 bars). 7 Horizontal color bars (no black or maximum brightness). Means Success In Electronic Servicing Circle (which can be superim- 3200 Sencore Drive, Sioux Falls, South Dakota 57107 posed over any pattern) Call Collect 605-339-0100In SD & AK CIRCLE 180 ON FREE INFORMATION CARD 15 NRI Trains You At Home-As You Build Your Own IBM PC Compatible Computer

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No computer stands alone...it's part of a total system. To really service computers, you have to understand computersystems.And only NRI includes a powerful computer system as part of your training, IBM is a Registered Trademark of IBM Corporation. Epson is a Registerad Trademark of Epson America. Inc. centered around the new, fully IBM PC compatible Apple and the Apple logo are Registered Trademarks of Apple Computer. Inc. Sanyo 880 Series computer. Compact is a Registered Trademark of COMPAQ Computer Corporation. 1985 AT&T Technologies. Inc.

16 You start with the step-by-step assembly of the new, highly -rated, Sanyo computer. You install and troubleshoot the "intelligent" keyboard. Then you assemble the power supply, install the disk drive, and add extra memory to give you a powerful 256K RAM system. The new 880 computer has two operating speeds: standard IBM speed of 4.77 MHz and a remarkable turbo speed of 8 MHz, making it almost twice as fast as the IBM PC. Next, you'll interface the high- Your NRI total systems training includes: resolution monitor and begin to use the valuable software supply-to ensure that you have NRI Discovery Lab- to design and modify also included with your complete computer system. all the essential skills you need circuits Your four -function, digital multimeter with walk.you.through It all adds up to confidence -building, real -world to succeed as a professional instructions on audio tape Digital logic probe for visual examination of keyboard experience that includes training in programming, circuit computer service technician. circuits The newest Sanyo 880 Series Computer with "intelligent" keyboard and design, and peripheral maintenance. You'll be learning 360K double -density, double -sided disk N o Experience Needed, drive High resolution monochrome about, working with, servicing, and troubleshooting an monitor 8K ROM, 256K RAM Bundled software including GW BASIC. MS-DOS, entire computer system-monitor, keyboard, computer, N RI Builds It In WordStar, CalcStar Reference manuals. disk drive, power This is the kind of practical, schematics, and bite -size lessons. hands-on experience that makes you uniquely prepared, with the skills and confidence you need for success. You learn at your own convenience in your own home. No classroom pressures, no night school, no need to quit your present job until you're ready to make your move. Your training is backed by your personal NRI instructor and the NRI technical staff, ready to answer your questions and help you when you need it. You get it all with NRI at-home training. 100Page Free Catalog Tells More Send the postage -paid reply card today for NRI's big, 100 -page, color catalog on NRI's electronics training, which gives you all the facts about NRI courses in Microcomputers, Robotics, Data Communications, TV/Audio/Video Servicing, and other growing, high-tech career fields. If the reply card is missing, write to the address below.

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19 Radio Greyscale staircase Color burst disabled Electronics ifitri= The various crosshatch and checkerboard patterns are primarily used for indicating linearity and color -convergence at the sides and corners of the CRT. (When the corner squares start to resemble diamonds you know its the monitor that's stretching the picture, not your eyes.) The pure white and black screens are great for optimizing the adjustment of RADAR SPEED UNIT. Used professional the CRT's min/max brightness model. Moving and stationary use, dual dis- range (blacks really look black- play, SPECIAL $199. Other models from not gray), while the all -red screen $275. For clocking speeds in skiing, racing, is used to test for color purity. bowling, baseball, etc. NEW IBM -COMPATI- BLE COMPUTER system. Fully expandable, If the picture has smear at includes monitor, graphics/printer card, 362K brightness -level transitions, pulls, floppy drive, game/serial ports, 256K memo- reflections, or other evidence of ry, AT -style keyboard, free programs. Mono- low -frequency misbehavior, the chrome, $8 9 5; color, $10 9 5.AIS line and field squarewave will SATELLITE, INC., P.O. Box 1226-D, Dublin, PA 18917. 215-249-9411. guide you right to the trouble - CIRCLE 214 ON FREE INFORMATION CARD spot. As far as the color bars are concerned, they are razor sharp at the color -bar transitions. Anything CALL NOW less than razor-sharp separation generally means that there's a AND problem with the monitor's frequency response. However, ex- RESERVE pect considerable separation YOUR SPACE smearing from a color TV because it simply doesn't have the overall 6 x rate $800.00 per each insertion. frequency response necessary for Reaches 245,824 readers. HUGE SHORTWAVE COMMUNICATIONS Fast reader service cycle. sharp transitions. CATALOG. Over 70 pages of the latest in Short lead time for the placement of The circle provides an excellent radio monitoring equipment. Includes com- ads. munications receivers, portable shortwave astigmatism test. Proper astig- radios, radioteletype and facsimile equip- matism adjustment can be ex- Call 516-293-3000 to reserve space. Ask ment, books, antennas, headphones and ac- for Arline Fishman. Limited number of tremely critical for the correct cessories. Explore the world from your living pages available. Mail materials to: display of computer graphics. Al- room with shortwave radio! Catalog available Computer Admart, RADIO -ELEC- though an astigmatism adjustment for $1 (refundable). UNIVERSAL SHORT- TRONICS, 500-B Bi-County Blvd., Farm- WAVE RADIO 1280 Aida Drive Dept. RE7, ingdale, NY 11735. usually is provided only on the Reynoldsburg, OH 43068 finest oscilloscopes, it can be par- tially simulated by a TV's H and V linearity controls. Since there is no easy way to use the circle part of a TV test pattern for a computer monitor alignment, and since few TV -station test patterns are transmitted during normal working hours, the circle overlay is one of the best tools for making critical astigmatism adjustments to high- performance TV and computer MEET THE WORLDS SMALLEST MULTI - monitors. Essentially, the circle FEATURED AUTO DIALER. Dials any of 100 SUPER HOLIDAY SPECIALS on our Multi - Stored numbers, accesses computer ser- overlayed on the 19V x 15H Channel Microwave T.V. receivers -1.9 to 2.7 vices and long distance networks. Features crosshatch makes a good sub- GHz-40 + dB Gain. 1 Complete System LCD display, electronic code for private num- stitute for a TV test pattern. ONLY $84.95 (shipping included). Buy 5 at bers, prefix encoding, redial and pause. Use The instruction manual claims $75.00 each and get 1 FREE. $2.00 Credit on as a calculator, stop watch, timer, alarm and a phone orders - CALL 602 230-0640 or send clock. Easily fits in shirt pocket. (21/2 x 3). In- that various color patterns can be your order to K & S ELECTRONICS, P.O. cludes full instructions and carrying case. attained by simultaneously de- BOX 34522, PHOENIX, AZ. 85067. We ac- $49.95 + $3.74 for shipping. Order toll free pressing two pattern switches, cept VISA/MASTERCARD/AMEX/COD. 1-800-624-1150. For a free catalog call (402) continued on page 30 Prices good thru December 31, 1987. 554-0383. UNITED IMPORTS & MFG., 6846 Pacific St. Omaha, NE. 68106 CIRCLE 194 ON FREE INFORMATION CARD CIRCLE 218 ON FREE INFORMATION CARD 20 ....*DMM MEASURES CAPACITANCE, TRANSISTOR 4Ih DIGIT TRMS MN READS FREQUENCY AND TEM- MORE... PERATURE B&K-PRECISION'S new 2905 is a mo-e-than-fuN-r The new 2945 is well suited fir both the analog End digital 31/2 digit DMM, at a surprisingly low 'rice. r worlds. DC V accuracy i:. 0.05%, wit! 1Onf.., dude 0.5% VDC accuracy; 100 µV, 0.1y" 0.01.0 resol ttion. Daa hod Feeaes voltage and r.urren- tion. Measures capacitance to 20mF v." reachngs. °C and F tem3ersture read ngs art from tion. Audible continuity and dial,- - 20° to + MOOT ficqueicy from 20 Fie to 20kHz. For field survivability, it fes AC voltage and cu -rent ale read in true RMS. Also verse polarity and ow-- checks continuity and diodes. S250.0) Contact: fusing. Contact: " B&K-PRECISION, 646D rortland Street, Street, Chicago, Chicago, IL., 60635 :312. 8194.087. B&K-PRECISIO 31/2 digit DMM, at dude 0.5% VDC acc B&K-PRECISION'S new 2 905 is more -than -full -feature 31/2 digit DMM, at a surprisingly low price. Features indude 0.5% VDC accuracy; 100 µV, 0.1µA, 0.111, resolution. Measu capacitance to 20mF with up to 1pF resolution. Audible continuity and diode junction tests are built in. For field survivability, it features a drop resistant case, reverse polarity and overload protection and high-energy fusing. Contact: B&K-PRECISION, 6460 W. Cort- land Street, Chicago, IL 60635 (312) 889-9087. 111.11.1.111.:1 IIIThird 11.07111111111 FREQUENCY COUNTER AND DATA HOLD HIGHLIGHT NEW 41/2 DIGIT DMM For engineers in need of a high - accuracy 41/2 digit DMM and a low range frequency counter the 2940 is made to order. DC voltage accuracy is 0.05%. Resolution is 10µV,10nA, and 0.0111. Frequency measure- T' ments span from 20Hz to 200kHz with up to 1Hz resolution. The 2940 features a drop resistant case with full eeoi internal circuitry protection. ELISION 5.00 Contact: B&K- ION, 6460 W. Cortland Street, Chicago, IL etter specs 60635 (312) 889-9087. cwer pices HAND-HELD TEST BENCH READS VOLTAGE, More features RESISTANCE, CURRENT, HFE TEMPERATURE AND LOGIC. The new 2906 31/2 digit DMM from B&K-PRECI- More capabil'rties SION is virtually a hand-held test bench, with a remarkable range of functions. °C and °F temperature More circuit and measurements cover from - 20C to 1000°C. The logic safety poteation capability is ready for TTL and CMOS circuits. Other features include drop resis- Ruggedized case with tant case, reverse polarity and overload protection; safety test leads plus high-energy fusing. DC accuracy, 0.25% Five all -new models step ahead of the competition with better specs and VDC. 1..01:11(1 Contact: higl-er performance per dollar. We've also packed more Features than ever B&K:YRYCISION, into every model. 6460 W Cortland Street, AI' f ve instruments measu-e voltage, current and resistance, check Chicago, IL 60635 (312) 889-9087. con-inui1), and dioces, cnd feature a new ergonomic case with angled LCD readout. Depending on model, additional capabilities induce logic level, capacitance measurement. -rarsistor gain, true RMS, frequency TRUE RMS DMM OFFERS PEAK HOLD. CAPACI- measurement, high -current measurement, data hod, peak hold and eve TANCE, AND LOGIC tem perature. 31/2 digit true RMS handheld Like all B&K-PRECISION instruments, these new meters are made for the DMM featuring 0.1% DC real world. They offer a drop- resistant case and the triple protection of accuracy. Housed in an reverse polarity prctection, overload protection, and h gh-energ\, fusirg. ergonomic, drop -resistant case, the 2907 offers many Best of all, the B&.{ -PRECISION DMM you want is already in :;tock at your functions and a low price. occl distributor. Cal today for full details. Resolution is 100µV, 0.1µA and 0.111. Capacitance to 20µF with 1pF resolution. Peak hold feature freezes transient readings. Fully BIC PREZISMN protected. Also checks logic, continuity and diodes. OYNAIIICAN CORPORATION 190. Contact: B&K-PRECISION, 6460 W. Con - 6460 West Cortlanc St Chicago, IL 60635 3124389-9C137 Tana -Street, Chicago, IL 60635 (312) 889-9087. International Sales, 6430 W Cortland St., 2.hicagc, IL 60635 Canadian Sales, Atlas Electronics Ontario South and Central American Sah. Empire Exporters, Plainview, NY 11803

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1825P 59.95 1964'5.095 Membership Benefits Big Savings. In addition to this introductory offer, you keep saving substantially with members' prices of up to 50% off the publishers' prices. Bonus Books. Starting immediately, you will be eligible for our Bonus Book Plan, with savings of up to BO% off publishers' prices. Club The. News Bulletins. 14 times per year you will receive the Book Club News, describ- BENCHTOP - ing all the current selections -mains, alternates, extras -plus bonus offers and special sales, with hundreds of titles to choose from. Automatic Order.If you = ELECTRONICS want the Main Selection, do nothing and it will be sent to you automaticallyIf REFERENCE - you prefer another selection, or no books at all, simply indicate your choice on 2706P59.95 the reply form provided. As a member, you agree to purchase at least 3 bocks MANUAL - within the next 12 months and may resign at any time thereafter. Ironclad No -Risk Guarantee.If not satisfied with your books, return them within 10 days VICTOR F.C. VELEY without obligation! Exceptional Quality. All books are quality publishers' editions especially selected by our Editorial Board. FREE when you join! Reference Guide to 2785534.95 Electronics Manufacturers' I'M I irtv, Counts as 2 1599P S16.95 1529PS14.95 Publications A time- and money -saving list INTEGRCIRCL ATE( ITS of product literature from all the major electronics suppliers. (a $6.95 value)

2715516.95 2609P 816.95 ELECTFIDNICS BOOK CLUE . P.O. Box 10, Blue Ridge Summit, PA 17214 BEGINNER'S Please accept my membership in the Electronics Book Club' and send the 5 E1INTREIN1, TV REPAIR volumes listed below, plus my FREE copy of Reference Guide to Electronics ZEST £9111:r Manufacturers' Publications (2683P), billing me $3.95 plus shipping and handing charges. If not satisfied, I may 'eturn the books within ten days without obligation and have my membership canceled. I agree to purchase at least 3 books at regular Club prices (plus shipping/handling) during the next 12 months, and may resign any time thereafter.

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PACKET RADIO READING HANDBOOK SCHEMATICS

MASTEN Name IC Address COOPII°431 City State/Zip Phone 2722P$14.95 199P576.95 1536P58.95 Valid for new members only. Foreign applicants will receive special ordering instructions. Canada (Publishers' Prices Shown) 1987 Electronics Book C ub' must remit in U.S. currency. This order subject to acceptance by the Electronics Book Clubs . Blue Ridge Summit. PA 17214 RE -1'87 AU books are hardcover unless otherwise indicated 23 Smaller than a quart container of panel display. It has a suggested milk and the weight of a standard retail price of $159.00. telephone, each two -cube speak- The model 2008 is stereo, and (Sterlingm er array can literally fit in the palm comes in two pieces. One con- of a hand. Two of those arrays and tains the radio and left -channel an Acoustimass module (about the speaker; the other contains the size of a typewriter) comprise the right -channel speaker. It has all of precision system. the features of the model 100 except dual alarms. Besides stereo reception and reproduction, the drills model 2008 offers an auxiliary input suitable for a tape deck or CD uariable or constant I speed .. from the player. It has a suggested retail Maxi to the Mini! price of $275.00.-KLH Division of Kyocera Electronics, Inc., 100 Ran- Amp.. dolph Road, CN 6700, Somerset, NJ 08873-1284.

CD MUSIC SYSTEM. The model CR- CIRCLE 11 ON FREE INFORMATION CARD CD10, combines an AM/FM-stereo compact disc player and a built-in In addition to the flexibility of- digital clock timer. The top -load- fered by the small and adjustable ing CD player features Automatic cube -speaker arrays, the model Programmable Music Selector and AM -5 is available with several Automatic Program Search System mounting brackets and accesso- functions. Twin 31/8" speakers de- ries that allow it to be placed or liver full-bodied sound. The LCD suspended anywhere. The wide - clock section features a conve- range driver in each cube speaker nient wake-up timer and a sleep is also magnetically shielded for function. use with a video monitor or TV set. The model AM -5 is priced at $699.00.-Bose Corporation, The Mountain, Framingham, MA 01701.

TABLE -TOP RADIOS. The model 100 (shown) and the model 2008, are compact clock radios with the controls and the sound of a high- CIRCLE 13 ON FREE INFORMATION CARD fidelity system. The model 100 is monaural, and The model CR-CD10 has a sug- Crated in Nest Germany, features frequency -synthesis tun- gested list price of $319.95.-Sharp the sigh -speed, low- ing with three memory presets, Electronics Corporation. Sharp votage, h ino-held drills 3-E >xtrenely quiet, high -density pressboard cabinet, Plaza, Mahwah, NJ 07430. ightweigh and cool separate bass and treble controls, ,unr ing w'th a very low vib-ation level. Speeds dual independent alarms (buzzer CTCSS ENCODER. The model range from 0-21,000 RPM at one time, music at another), SS-32SMP, is designed for use in with a universal chuck to ramp -up (increasing -loudness) handheld radios and other size -re- accommodate accessories Jp to .125 in size. alarm, continuously variable stricted applications. It measures Accessories for any "sleep" timer, and dimmer con- .53 x 1.00 x .16 -inch, and offers appricaticn! Adapt your drill to all your trol. Time, station, and status are full tone versatility and a high au- exacting reeds with over indicated on a liquid -crystal front - dio level. 100 high quality drill bits, Any 32 tone frequencies be- grinding stones and wheels, saws, cutting tween .01-255 Hz may be selected wheels, sanders, brushes, for storage into a 32 -bit EEPROM polishers and other accessories. Available in memory. The tone frequencies can "kits" or as separate items. be standard or non-standard, and Your exacting standards may be changed at a later date if demand Sterling quality. desired. The required tone frequency is selected by soldering WAHL CLIPPER CORPORATION binary-coded jumpers on the tone 29C0 Least St -eel, Sterling, IL 61081 board. The model SS-32SMP may 1815) 625-5E25 also be ordered to work as a six - CIRCLE 176 DN FREE INFORMATION CARD CIRCLE 12 ON FREE INFORMATION CARD tone encoder (no switching di -

24 HITACHI COMPACT SERIES SCOPES 6" CRT with Internal Graticule Delayed Sweep ±3% Accuracy Dual Channel X -Y Display Single Sweep Bandwidth Limiter Sweep Time Autoranging Trigger Lock 400V High Input CRT Readout Voltage Protection TV Sync Trigger Circuit

V-1065 V-1060 DC to 100MHz DC to 100MHz $1345. Save $150! With Cursor Readout V-665 DC to 60MHz $1595. WIth Cursor readout. Save $200! $1145. Save $150! PROBES INCLUDED WITH ALL HITACHI V-660 DC to 60MHz SCOPES AT NO EXTRA CHARGE! $970. Save $125! V-223$695.Save$100! DC to 20MHz, Dual Channels, Delayed Sweep CRT: 6' rectangular with 2k V Potential POLAROID® Vertical Deflection: Ver. Modes: CH1, DS -34 CH2, ALT, CHOP, ADD (DIFF). Bandwidth: DC to 2CMHz(-3dB). Sensitivity: 5mV/div CAMERA to 5V/div. Max Sensitivity: 1 mV/div at X5 Mag. Extends. X -Y Operation (CH1:X, CH2:Y): 3° or less from DC to 50kHz Weight: 7kg (15.51b)

V-209 DC to 20MHz, Dual Channels CRT: 6" rectangular with 1.5k V Potential Vertical Deflection: Ver. Modes: CH1, CH2, ALT, CHOP, ADD (DIFF) Bandwidth: DC to Save $135! $290. 20MHz(-3dB). Sensitivity: 5mV/div to 5V/div. Instant Hard Copy From Oscilloscopes Max Sensitivity: 1mV/div at X5 Mag. Extends 5', 6" and 7" Hoods (Available separately X -Y Operation (CH1:X, CH2:Y): 3° or less @ $51 ea. Please Specify size) from DC to 100kHz Pistol Grip For Ease of Operation Weight: 5kg (1 1 lb) Wo.-ks on Any Make of Oscilloscope Three Full Year Warranty V-212 $440. Save $175! $822.Save $175! 4-1100A DC to 100MHz, Quad Channels, Delayed Sweep 117.:-.1b. II VC -6020 $2240. Save $250! GS 6 ,'kit $1750. V-680 DC to 60MHz, Triple Channels, 441 0.0 01 Save $200! Delayed Sweep $1340. Save $1501 V-423 DC to 40MHz, Dual Channels, 1MHz Sampling, Single Time Base Delayed Sweep Dual Channels $745. Save $250! DC to 20MHz, Dual Channels Usable as both a conventional oscilloscope and a digital storage V -1050F DC to 100MHz, Quad scope. 2kV Potential CRT: 6" rectangular with 2k V 6' CRT DC to 20MHz(-3dB). Sensitivity: Channels, Delayed Sweep 5mV/div to 5V/div.GPIB, IEEE 488Reeolution: 8 bi.Max. Storage $1445. Save $150! Vertical Deflection: Ver. Modes: CH1, Free:103k Hz( -3c113).Memory Capacity: 1k words/ch. Hot Res.:100 CH2, ALT, CHOP, ADD (DIFF). Band- nt/dIv. Sweep lime: 0.1m/div to 1s/dIv.Data output: Analog. V -650F DC to 60MHz, Triple Channels, width: DC to 20MHz(-3dB). Sensitivity: Delayed Sweep $1070. Save $1251 5mV/div to 5V/div. Max Sensitivity: WM. B. ALLEN V-422 DC to 40MHz, Dual Channels 1 mV/div at X5 Mag. Extends. $ 795. Save $1301 X -Y Operation (CH1:X, CH2:Y): 3° or SUPPLY COMPANY less from DC to 50kHz ALLEN SQUARE V-509 DC to 50MHz, Dual Channels, Delayed Sweep $1195. Save $250! Weight: 6kg (13.3 lb) 300 Block North Rampart Street V -058G DC to 5MHz, Dual Channels V-222 Same as above, New Orleans $338. Save $100! but with CH1 output Louisiana 70112 and DC offset voltage monitor outlet TOLL FREE 800 535-9593 LA 800 462-9520 V-134 DC to 10MHz, Dual Channels $1420. Save $2001 available for external counter or DVM. NEW ORLEANS :504) 525-8222 FAX (504)525-6361 American Express Visa MasterCard V-425 DC to 40MHz, Dual Channels $515.Save $200! 928 pg CATALOG free with your order $845. Save $1501

CIRCLE 103 ON FREE INFORMATION CARD 2' odes are necessary) at no extra can for $8.00.-Lab Products, 29501 charge. Multiple -tone switching Greenfield Road, Suite #109, CRYSTEK over six tones can be done with Southfield, MI 48076. switching -diode networks or a The pulse of dependable binary switch. Tone frequencies INEAR AMPIIFIFR. The model above 255 Hz can be ordered for a SB-1000, provides a full 1000 -watt communications slight additional charge. PEP SSB output, or an 850 -watt CW output. Reliability & Quality It provides full HF Fromtart To Finished Product coverage from 160 to 15 meters, including 80% of rated output on the three WARC bands. The amplifier

uses a single 3-500Z tube in a high - -cA efficiency circuit, and has a hyper- silsteel E -I core transformer for high-performance operation. It

4)° CIRCLE 14 ON FREE INFORMATION CARD

The model SS32SMP features a low -impedance, low -distortion, adjustable sinewave output that QUARTZ CRYSTALS/OORSCILLATORS can provide sufficient deviation F for most handheld radios. It oper- ELECTRONIC - INDUSTRIAL ates on 6-15 volts DC so that volt- CIRCLE 16 ON FREE INFORMATION CARD Micro -Processor Control age -dropping resistors should Computers/Modems never be required. Itis priced at also features a quiet computer - Test/Measurement Medical $27.95.-Communications Spe- style fan, a full -wave power supply COMMUNICATIONS -REPLACEMENT cialists, Inc., 426 West Taft Avenue, with computer grade capacitors, Mobile/2-way/Channel Elements Orange, CA 92665-4296. adjustable ALC, and vernier -tuned Pagers plate and load controls. Marine TOTAL ELECTRONICS CLEANER. The model SB-1000 is priced at Aircraft Telemetry TEC is an improved formula con- $739.95-Heathkit, P.O. Box 1288, Monitors/Scanners taining a cleaning product that has Benton Harbor, MI 49022. AMATEURS been used by professional techni- CB cians for years. Itis a non -con - RELAY SERVICE KIT. The model Hobbiest Experimenter ITK-64, contains a comprehensive COST EFFECTIVE tool selection for relay mainte- MODERATE PRICING nance. Furnished in a compact 121/2 FAST DELIVERY x 10 x21/4 -inch padded zipper case, the tool selection includes

The Pulse of Dependable Communications Crystek Crystals offers their new 16 page CIRCLE 15 ON FRLL INFORMATION CARD FREE catalog of crystals and oscillators. Offering state-of-the-art crystal components manufactuered by the latest ductive, non-toxic, residue -free, automated technology. Custom designed or "off the shelf," Crystek meets the need, anti -static, rapid -drying elec- worldwide. Write or call today! tronics -grade solvent that removes CRYSTEK CRYSTALS dust, dirt, oil, and oxides. Itis 2351/2371 Crystal Dr. Ft. Myers, FL 33907 completely safe for use on com- P.O. Box 06135 Ft. Myers, FL 33906-6135 puter, video, audio, telephone, TOLL FREE 1-800-237-3061 and business equipment. TEC is (813) 938-2109 - TWX 510-951-7448 available in an eight -ounce spray CIRCLE 17 ON FREE INFORMATION CARD CIRCLE 205 ON FREE INFORMATION CARD 26 over 40 items, including brushes, A -B switch, and is supplied with Corn Data Products, 1755 Osgood burnishers, files, gauges, lamp ex- three BNC connectors. The large Street, North Andover, MA 01845. tractor, mirror and magnifier, igni- actuator provides a positive tion wrench, pliers, circuit tester, switching action. That design in-. REMOTE POWER SWITCH. The soldering iron, wire stripper, and corporates an unusually high iso- model R119, is a single -outlet de- more. lation between unused lines. vice that can be used for remote The model JTK-64 is recom- The switch is easily mounted on control of multiple -outlet strips, mended for professional service the side of a desk, or on a wall, by surge suppressors, computers, or and repair of magnetic relays and use of two-sided adhesive tape (in- peripherals. It features a Velcro solenoids in telephone/communi- cluded). It is equally useful in of- mounting pad, so that it can be cation systems, process controls, fices or labs where there is a need placed conveniently under a desk and other plant equipment. Itis for switching coaxial lines that ter- or work table to control an entire priced at $289.-Jensen Tools, 7815 minate with BNC connectors. The workstation. S. 46th Street, Phoenix, AZ 85044. model DSK is priced at $22.00.-L - The model R119 converts a sur-

MODULAR OSCILLOSCOPE PRO- BES. The SP300 Series, range in FLUKE Immediate bandwidth from 10 MHz to 100 Delivery MHz and adapt to all oscilloscopes. They feature replaceable tips, probe cables, probe heads, and ground leads. De- signed to be used in a wide Is at SALE PRICES! number of applications, each pro- 31/2 DIGIT 3200 COUNT 40th Year be is equipped with its own ac- ANALOG/DI MULTIMETERS Anniversary Sale cessory kit having two insulating tips, a quick -connect BNC adapt- Value Leader -World's Most Popular FLUKE 025% DC Accuracy, Audible er, a spring hook, and a trimmer. anging on

1 $169

3 YEAR MOdet -/ARRAN1l, 0.1% DC Accuracy, Audible Con- tinuity & Conductance Function

reg. $249 Model 8024B 0.1% DC Accuracy, 11 Functions Peak Hold, Temperature

reg. $249 CIRCLE 18 ON FREE INFORMATION CARD Model 8026B , 0.1 VDC Accur Arbdel 77 0 1%DC True RMS AC Volts A highly -flexible silicone -insu- 2 yr. Warranty & Current lated probe cable is offered in one, Model 80218 two, and three -meter lengths. A $219

read-out actuator option for use 41/2 DIGIT TRUE RMS YEAR WARRANTY MIS11111111.1V BENCH DMMS with all x10 probe cables is also HAND HELD Model 901 8012A-01 available. 31/2 Digit 10 Wth Rechargeable Battery Prices for the SP300 Series start Measures True RMS AC Volts & leg $289 reg. $399 Amps, dB + Frequency From 12 it Model 5010A-01 Model 8050A at $27.00.-OK Industries, Inc., Resistance to 300 M mo With Rhargeable Battery 41/2 Digit Relative Ref. 3455 Conner Street, Bronx, NY $359 eg $329 Function 0.03% DC Accuracy 10475. 1'01 Model 9012A reg. $399 Same as 8060A but Less 31/2 Digit Two Low Ranges Model 8050A-01 With Rechargeable Battery COAXIAL SWITCH. The model Reg $359 Model 8060A reg $439 DSK, measures only 3.1" x 1.9" x 'True PUS AC TO 50/ KHz 'Conductance Function 1" overall. It functions as an SPDT WARRANTY Checks High Resistance

Send to FREE 480 page 'Industrial JOSEPH ELECTRONICS, INC. Products Catalog' I understand it is FREE with any order or if requested on 8830 N. Milwaukee Ave. Dept. R company letterhead. (Otherwise. $4.95 Niles, IL 60648 to cover catalog and shipping cost.) Rush merchandise per attached order ORDER TOU. FREE I understand rated accounts are shipped open account; otherwise send per credit card 1-800-323-5925 O visa Master Card Drscover IN IWNOIS Check El Money Order I; Rush Catalog 312-297-4200 Card No. Exp Date I SINCE 1947 'Nauru Company CIRCLE Pi ON FREE INFORMATION CARD L alE1311111113% State zip 27 Radio- Electronicsraw

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DECODE NEARLY ANY SINGLE LEVEL APPLIANCE REPAIR HANDBOOKS -13 GATED PULSE SIGNAL. New circuit works SIMPLY SNAP THE WAT-50 MINIATURE FM volumes by service experts; easy -to- with Hamlin, Jerrold, Sylvania, and Eagle TRANSMITTER on top of a 9v battery and understand diagrams, illustrations. For major systems. Decodes In -band, Out -band, AM or hear every sound in an entire house up to 1 appliances (air conditioners, refrigerators, FM reference. Complete educational kit in- mile away! Adjustable from 70-130 MHZ. Use washers, dryers, microwaves, etc.), elec. cluding P.C. board, parts, case, and 40 page with any FM radio. Complete kit $29.95 + housewares, personal -care appliances. gated pulse theory booklet is only $47.00 $1.50 S + H. Free shipping on 2 or more! COD Basics of solid state, setting Up shop, test plus $3.00 shipping. Order no. 1PFD-1K. add $4. Call or send VISA, MC, MO. DECO instruments. $2.65 to $5.90 each. Free ELEPHANT ELECTRONICS INC. P.O. Box INDUSTRIES, Box 607, Bedford Hills, NY brochure. APPLIANCE SERVICE, P.O. Box 41865-R, Phoenix, AZ 85080. (602) 10507. (914) 232-3878. 789, Lombard, IL 60148. (312) 932-9550. 581-1973 CIRCLE 127 ON FREE INFORMATION CARD CIRCLE 84 ON FREE INFORMATION CARD CIRCLE 120 ON FREE INFORMATION CARD all MIR i

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DESCRAMBLER PARTS Origi- SIGNAL STORAGE AND DRIVER -AN OS - nal parts as called up in Radio Electronics COPE ACCESSORY. Dual channel. Input Feb 1987 article on tri-mode descrambling. and output sensitivity:±- 50mV to 15V. 10Mit CABLE TV CONVERTERS AND DE - Includes pc board, ac adaptor, resistors, ca- input, 10mA output. Automatic internal sync. SCRAMBLERS. Large selection of top pacitors, diodes, pots, transistors, IC's, Stores 4 cycles minimum. Frequency switch quality merchandise. Low prices. Quantity LED's, toko coil and Plessoy SAW filler. Arti- with ideal ranges of .5Hz to 100kHz with a discounts. We ship COD. Most orders are cle included. $59 plus $2.50 shipping. ELEC- maximum dependent on the 8MHz sample shipped within 24 hrs. Send $2.00 for catalog. TRONIC PARTS, Box 276, Alburg, VT rate. Intermittent problem mode for isolating CABLETRONICS UNLIMITED, P.O. Box 05440 (514) 739-9328. your system transient faults. $830. BIDAN 266 Dept. R, S. Weymouth, MA 02190 (617) ASSOC. P.O. Box 907 Princeton, TX 75077. 843-5191 CIRCLE 206 ON FREE INFORMATION CARD CIRCLE 195 ON FREE INFORMATION CARD CIRCLE 212 ON FREE INFORMATION CARD

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,,., ..., PANASONIC CABLE CONVERTERS, Wholesale and Retail. Scientific Atlanta and ...--.. NEW -SURFACE MOUNT COMPONENT Pioneer Cable Converters in stock. Pan - KITS. Half the price of most competitors. asonic model 130N 68 channel converter GUARDIAN STUN GUN: the most advanced Each kit contains 300 components, 10 each of $79.95, Panasonic Amplified Video Control personal protection device of it's kind. Gener- 30 different values. Resistors are 5%, 1/8 Switch Model VCS -1 $59.95. Scientific Atlan- ates a charge of electricity over 50,000 volts watt, 10 to 2.2M ohms. Capacitors are 20%, to Brand new Model #8528 550MHZ 80 to repel an attacker. Non -Lethal effect due to 50 WVDC, 33pf to .1uf. CMOS & TTL kits Channels Converter $89.95. Video Corrector low amperage. Safe and effective. Recom- available soon. Resistor Kit $29.95, Capaci- (MACRO, COPYGUARD, DIGITAL) EN- mended by many police agencies. Check lo - tor Kit $39.95, + $3.00 S + H. COD add HANCER $89.95. We ship to Puerto Rico, cal laws for restrictions. $39.95 + $3.00 $4.00 VISA, MC, MO call (714) 987-2414, Caribbean countries, & So. Amer. Write or call shipping w 30 -day return privilege. Call or VALUE COMPUTER, Box 1151, Alta Loma, BLUE STAR IND., 4712 AVE. N, Dept 105, write: LIFE PRODUCTS, PO Box 2126, Hen - Ca. 91701 Brooklyn, NY 11234. Phone (718) 258-9495. derson, NV 85014, (702) 871-1885. CIRCLE 209 ON FREE INFORMATION CARD CIRCLE 85 ON FREE INFORMATION CARD 28 CIRCLE 208 ON FREE INFORMATION CARD Radio- Electronics1111Eirl=

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QUALITY FIELD SERVICE KITS and test ZENITH SSAVI-1 $169, LEVEL II $199. equipment, production aids, telecommunica- FREE CATALOG OF HARD-TO-FINC Original reconditioned UHF input channel 3 tion equipment, maintenance and repair TOOLS is packed with more than 2000 output units with thirty -day limited warranty. tools, work stations, and static control prod- quality items. Your single source for precision SSAVI-1 project handbook $6.50 ppd. Sur- ucts can be found in the new TIME MOTION tools used by electronic technicians, engi- plus Sylvania 4040 converter/DIG, Z-tac, TOOLS catalog. All Time Motion Tool prod- veers, instrument mechanics, schools, labo- N-12, MLD-1200. Quantity discounts. Satel- ucts carry out guarantee of complete satisfac- ratories and government agencies. Also lite systems, converters, amplifiers. video action, or your money back within 30 days. For a contains Jensen's line of more than 40 tool cessories. Catalog $1. AIS SATELLITE, FREE catalog write: TIME MOTION TOOLS, kits. Send for your free copy today! JENSEN INC., P.O. Box 1226 -RE, Dublin, PA 18917. 410 S. Douglas Street, El Segundo, CA TOOLS INC., 7815 46th St., Phoenix, AZ (215) 249-9411. 90245. (213) 772-8170, Ext. 101. 85044. (602) 968-6231. CIRCLE 81 ON FREE INFORMATION CARD CIRCLE 215 ON FREE INFORMATION CARD CIRCLE 115 ON FREE INFORMATION CARD WI ,,,t III ...... mob :-.049'fic'r1': 41.4.40 t -

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U CI - SURFACE MOUNT COMPONENTS -Re - BUILD STEVE CIARCIA'S NEW VIDEO DIGITIZER. True "Frame Grabber", pic sistors, diodes, transistors (ROHM CORP), takes 1/60th sec Not bus Dependent - ceramic caps (NOVACAP) and tantalum caps (MATSUO). Standard resistor chip values THE MODEL WTT-20 IS ONLY THE SIZE OF Standalone digitizer Serial output, transmits 300bps to 57.6Kbps Resolution: range from 0 ohm to 10 Mohm. Ceramic cap A DIME, yet transmits both sides of a tele- chips range horn 1pf to 1uf. Tantalum cap phone conversation to any FM radio with 256 x 244 x 6 w/64 level grayscale Accepts chips range from .1 uf to 100 uf. Engineering crystal clarity. Telephone line powered - never any NTSC video input, B&W or Color design kits are available -packaged for con- Optional Rec/Display makes Video Tele- needs a battery! Up to 1/4 mile range. Adjusta- venient lab usage in plastic boxes or steel ble from 70-130 MHZ. Complete kit $29.95 phone Images can be stored & displayed on IBM PC. Kits starting at $89.50. Call for cabinets. GARRETT INST. & COMPAEU -$1.50 S + H. Free Shipping on 2 or more! INC., 3130 Skyway Dr. #104, Santa Maria, other options and specs. COD add $4. Call or send VISA. MC, MO. CCI, 4 Park St., Suite 12, Vernon, CT 06066. CA 93455. Phone (805) 922-0594, FAX DECO INDUSTRIES, Box 607, Bedford (805) 922-3643. Hills, NY 10507. (914) 232-3878. (203) 875-2751. CIRCLE 216 ON FREE INFORMATION CARD CIRCLE 210 ON FREE INFORMATION CARD CIRCLE 127 ON FREE INFORMATION CARD

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irAZI I I ' '=tF.1.5.1.,-7 ---- 4 $-,.._.,...-.,...... - ...o,L._ -...".:-:"" DECODE THE NEW VIDEO TAPE COPY ...,...,...- PROTECTION SCHEME. Bothered by FREE 24 PAGE OCTE CATALOG! Cable TV brightness changes, vertical jittering and vid- SCIENTIFICATLANTAcableequipment. In- converters, hand controls, stereo decoders eo noise while watching rented tapes? Stop it troducingthe newKeyCircuits,made to and switching centers. Negative cable TV with the LINE ZAPPER. New kit removes "test andrepair"8500(KEY-A) and traps and noise filters. Descrambler books, copy protection that often interferes with nor - 8550/8555(KEY-B)converters.Regular schematics and parts. SCA books and kits. mal television operation. Complete KIT only price $160.00.SpecialIntroductoryOffer Nite viewers. Microwave downconverters. $69.95. Assembled with 1 year warranty $125.00. Totalchannelcapability.Complete Telephone privacy assurance devices and $124.95. Add $3.00 shipping per unit. Dealer 8500 or 8550converters$225.Hand remotes automatic conversation recorders. Bug and inquiries welcome. ELEPHANT ELEC- $20.00. Freeinformation.Dealerswelcome. tap detectors. Parabolic microphones. Power TRONICS, Box 41865-L, Phoenix, AZ C.O.D. accepted.V.I.P.ELECTRONICS,P.O. supplies. Surplus electronics parts. OCTE 85080. (602)581-1973. Allow 6 weeks for Box 628,Forestdale,R.I.02824. (617) ELECTRONICS, Box 276, Alburg, VT delivery. 755-9778. 05440. (514) 739-9328. CIRCLE 213ONFREEINFORMATIONCARD CIRCLE 217 ON FREE INFORMATION CARD CIRCLE 188 ON FREE INFORMATION CARD 29 HITACHI SCOPES AT DISCOUNT PRICES!

1*.ii lei'''. t 90 , 20MHZ 100MHZ

Model V212 $475 Model V1060 $1,340 Model V-212 20MHZ Dual Channel (1mV Sens.) $475 Model V-422 40MHZ Dual Channel (1mV Sens.) $899 15-25% Model V-425 40MHZ Dual Channel (with cursor) $795 Model V-660 60MHZ Dual Channel (Delayed Sweep) S999 OFF LIST Model V-1060100MHZ Dual Channel (Delayed Sweep S1,375 All above scopes have a 3 year guaranty on parts and labor PRICE ELENCO PRODUCTS AT DISCOUNT PRICES!

CIRCLE 21 ON FREE INFORMATION CARD 40MHz DELAYED SWEEP ge-suppressor or outlet strip to in- MO -1253 stant remote control by simply $550 plugging it in. The switch itself is lighted so that on/off status can be seen easily. The switch is rated for 20MHz DUAL TRACE OSCILLOSCOPE 35MHz DUAL TRACE OSCILLOSCOPE 1,800 watts, 15 amps maximum. The device is UL listed and fea- $359 MO.1251 $498 MO.1252 tures a one-year warranty; the Top quality scopes at a very reasonable price. Contains all the desired features. Elenco's 2 year guarantee assures you of continuous service. Two 1 x , 10x probes, diagrams and manual included. Write for specs price is $19.95.-Perma Power Elec- 100 MHz Test Probes. 1X.10X, Ref. (Complete with 5 accessories) Fits Most Scopes $22 tronics, Inc., 5601 Howard Street,

MULTIMETER with TRUE RMS 41/2 Chicago, IL 60648. R -E LA I CAPACITANCE AND DIGIT MULTIMETER Auto Ranging TRANSISTOR ral plus TESTER Model ----1 Manual Ranging M-7000 r -13I/2 Digit Meter Model e58..,---0 28 Functions EQUIPMENT REPORTS CM -1500A 47 $135 ...i Fully protected Reads Volts, Ohms. .05% DC Accuracy r.wr - Current, Capacitors, .1% Resistance M-1180 .7% Acy $36.95 continued frompage20 41,, 'dueTransistors a with Freq. Counter M-1182 .25% Acy $39.95 DiodesWICis 8 Deluxe Case M.1181 1% Acy $42.95 _ GF-8016 FUNCTION GENERATOR 10MHz OSCILLOSCOPE BREADBOARD such as the switches for a B&W with Freq. Counter - $219 crosshatch and the vertical color emqp., Model-",.. " - -- .-.,.. 4r .4 $239 a-1/ Model 9436 ---- bars. While it's true that pressing PrTTV IT Shown-- - 4111111114 Sine, Square, Triangle two switches creates unusual Pulse. Ramp, .2 to 2MHz 10MHz DC or ACS.3°°° color patterns, except for the two Frequency1 thru 10MHz Triggered Sweep 9430 1 100 pins $15 Calibrated Vert 8 Hor 9434 2 170 pins $25 GF-8015 without Freq. Meter $179 that create the all -red field, they Reads Volts 8 Freq 9436 2 860 pins $35 are useless. It's just something that DIGITAL TRIPLE POWER SUPPLY DIGITAL LCR METER SOMHz LOGIC PROBE occurs, and making mention of Model 20 nsec with memory that fact probably saves the com- XP765 LP -700 II L! $148 pany many complaints that "some-

$239 6, 4.,---4411.0:71111. toe. thing is wrong with my unit." 0-20V a 1A Model v .... " *WI..wipil in 0-20V a 1A LC1800 / The Video Wonderbox is line - 5V Ca 5A Measures: powered and toolbox size: only 8 Inductors. / $23 Fully Regulated, Short Circuit Protected with 2 Capacitors. x 2 x 55/8 -inches. The carrying Limit Cont. 3 Separate Supplies Resistors Logic Pulsar $23 XP -880 with Analog Meters $169.50 LP -800 handle is detented and also serves as an adjustable tilt -mount. No ac- DIGITAL 3 AMP POWER SUPPLY MULTI -FUNCTION COUNTERS Model cessories other than the instruc- XP750 tion manual are provided. Op- r --- F-1000 0IIE 1.20H $259 tional accessories for the unit 0-40V a 1.5A include a 75 -ohm BNC-to-BNC ca-

i.. *tt:. 'Mr*N. --0-1- 0-20V V 3A 4-14414R..ii4 F-100 el 79 ...... 1 120MH 47 I ble, a 75 -ohm BNC-to-IEC cable, Fully regulated, short circuit protected current limit control Frequency, Period, Totalize, Self Check with High - and a DB-9-to-DB-9 (IBM-compati- XP -850 with Analog Meters $129.50 Stabilized Crystal Oven Oscillator, 8 Digit LED Display ble RGB/RS-232) cable. For additional information write C&S SALES INC., 1245 ROSEWOOD DRIVE, DEERFIELD, IL 60015 = et 15 DAY MONEY 800-292-7711 (312) 459-9040 ASK FOR CATALOG BACK GUARANTEE to NCM Electronics, 1500 Wyat 2 Year Limited Guarantee! Add 5% for Postage ($10 max), IL Res., 7% Tax Drive, Santa Clara, CA 95054. R -E CIRCLE 109 ON FREE INFORMATION CARD 30 NEW IDEAS Simple multi -tone generator

LED1 and Q1. They must be facing #9V and close, and shielded from ambient light-perhaps by placing IC/ them inside a small cardboard or $ R/ 79/ C3 opaque plastic tube. Alternately, 82K .27 LED/ CZ you could try substituting an opto- R2 (RED) .27 SPXR / /X. 811 isolator for LED1 and Q1. However, 7217 -'V Ao(/57 R3 0/ bear in mind that the spacing be- 330n, SEE tween LED1 and Q1 provides some TEXT 1A /VI/1(UL control over the output waveform; 14/AVE /-0/241.5 an opto-isolator would eliminate that degree of control.-Mohd FIG. 1 Amjad Khan. R -E SOMETIMES YOU NEED A WAVEFORM tance, which causes a large voltage having a particular shape, fre- drop across R1. The comparator quency, or amplitude that's not immediately switches to a low out- NEW IDEAS provided by your signal generator; put, thereby turning the LED off, or maybe you just don't own a sig- which restores Q1's dark resis- This column is devoted to new ideas, circuits, device applications, construction tech- nal generator. If you don't mind tance. The increase in Q1's resis- niques, helpful hints. etc. spending a bit of time experiment- tance causes the cycle to repeat, All published entries, upon publication, will ing with parts values, the multi - thereby producing an oscillating earn $25. In addition, for U.S. residents only, Panavise will donate their model 333-The tone generator circuit described output voltage. Rapid Assembly Circuit Board Holder, having here might give you just the wave- Logically, the circuit should a retail price of $39.95. It features an eight - "lock up" because the LED and position rotating adjustment, indexing at 45 - form that's needed. degree increments, and six positive lock posi- The circuit shown in Fig. 1 can phototransistor would be compet- tions in the vertical plane, giving you a full ten - actually be built from parts you ing with each other for control of inch height adjustment for comfortable work- probably have lying around on the the circuit, and IC1 would get ing. I agree to the above terms, and grant workbench. A bi-polar power sup- stuck at some equilibrium state. Radio -Electronics Magazine the right to ply is required; two 9 -volt batteries Capacitor C2 prevents that from publish my idea and to subsequently re- publish my idea in collections or compilations wired in series, with their junction happening by keeping the LED lit of reprints of similar articles. I declare that the used as the "ground" will do. slightly longer that the normal attached idea is my own original material and turn-off time. (C1 also helps avoid that its publication does not violate any other copyright. I also declare that this material has How it works lock up, but its use isn't critical and not been previously published. Op -amp IC1 is used as a sen- it can often be eliminated.) sitive voltage comparator, whose The output frequency can be trip level-the value at which the changed by varying the values of output changes state-is deter- C1-C3, but keep in mind that mak- Title of Idea mined by potentiometer R2. The ing their values too small will de- resistance of R1 in series with the feat their primary purpose, which Signature resistance of phototransistor Q1 is avoiding circuit lock -up. provides the feedback divider for The frequency, amplitude, and IC1's inverting input. Since Q1's the shape of the waveform are de- Print Name Date "dark" resistance-the resistance termined by R2. Three of the typ- when there is no light-is very ical waveforms that can be Street high. Very little voltage appears obtained by adjusting R2 are also across R1; therefore, IC1's output shown in Fig. 1. will normally be high. LED1 can be any red light -emit- City State Zip When power is first turned on, ting diode. Q1 can be any pho- Mail your idea along with this coupon IC1 goes high, causing the LED to totransistor-try whatever you to New Ideas Radio -Electronics. glow. However, the instant it glows have lying around or can get 500-B Bi-County Boulevard it shines on Q1, causing a decrease cheaply. The only critical part of Farmingdale. NY 11735 in Q1's collector -emitter resis- the assembly is the positioning of

31 SERVICE INTERNATIONAL SOCIETY OF C rir CERTIFIED ELECTRONICS TECHNICIANS LOG 2708 West Berry St.Ft. Worth, TX 76109 Surface -mount components

THE BIGGEST CHANGE IN ELECTRONICS dustrial product manufacturers can be tricky. J -lead devices are since the widespread use of the are currently gearing up for sur- soldered underneath the outline integrated circuit is now begin- face -mount technology. Industry of the package itself, making re- ning. It will affect virtually all in- estimates indicate that within five moval difficult. dustrial and consumer electronic years 80% of all devices will be sur- Manufacturers generally recom- products and cause some grief for face -mount types. mend special tools for the testing, the technicians who must service removal, and replacement of SMT and maintain those products. In Advantages devices. Even with these tools, the fact, just as in the transistor transi- Manufacturers are moving to job of servicing of SMT devices is tion days of the late sixties, some SMT for several reasons. With the tedious. Lead spacing is generally technicians will flatly refuse to development of more complex 50 mils, half that used on standard work on the new systems. Yet, un- IC's, the number of pins needed DIP's. Attaching test leads to 50 - like the development of IC's and on the package has increased. Be- mil leads that lay beneath a pack- the introduction and proliferation cause a Dual In -line Package, or age can be a problem unless a spe- of the microprocessor, the coming DIP, is not economical if more than cial test clip is used. Alignment of revolution does not inherently in- 48 pins are required, new pack- the replacement part and the sol- volve the introduction of radically ages had to be developed. Those der pads-which is essential for new devices. This revolutionary include the Plastic Leaded Chip SMT devices-is tricky. change is the simple packaging of Carrier (PLCC) and Leadless Finally, SMT resistors and capac- components in new cases. It is Ceramic Chip Carrier (LCCC), and itors are so small that their values called Surface -Mount Technology, were designed to accommodate or part numbers cannot be printed or SMT. more pins and to take advantage of on them. Good documentation Today, the vast majority of com- SMT. SMT packages for both IC's becomes imperative for successful ponents are attached to printed - and passive components are 60% service of equipment that is SMT- circuit boards by passing their to 80% smaller than insertion - based. Look for manufacturers to leads through holes in the PC mounted packages. That allows begin special training on SMT ser- boards and soldering them to con- the design of smaller printed cir- vicing early next year.-Elmer Poe ductive pads on the other side. cuit boards. It also shortens inter- CET, PhD This is known as insertion -mount connecting leads and allows the technology and is used to attach development of faster boards. Be- virtually all conventional IC's, tran- cause SMT packages are soldered sistors, resistors, capacitors, and on the side of the PCB to which inductors to boards. Surface - they are mounted, components mount technology involves the can be mounted on both sides of connection of components to the the board. This also lessens the surface of the printed -circuit number of layers needed for a typ- board by simply laying a compo- ical board. nent's leads on conductive pads under the component and solder- Disadvantages ing them. Surface -mount devices Unfortunately for the techni- are soldered on the side of the cian, this miniaturization is not board to which they are mounted. without disadvantages. Many sur- } r-- - Several major consumer and in - face -mounted components are glued to the board before solder- Reprinted courtesy of ISCET from Technical Reference Log, which is provided to mem- ing. Removing a glued device "How was I supposed to know you bers of ISCET at no charge. without damaging the solder runs have to plug it in?!"

32 AUDIO UPDATE

Stereo Spatial Imaging LARRY KLEIN, AUDIO EDITOR

IN PAST MONTHS WE'VE DEVOTED SEV- range, so can imaging. There was eral columns to those special one highly esteemed British pho- products and techniques used to no cartridge whose coils had a ma- enhance spatial perspective and trixed output. If the coils were not imaging in stereo listening. Dedi- properly aligned via a small set- cated audiophiles, who would screw adjustment, there would be never dream of adding "artificial" a high level of out -of -phase enhancement devices to their sys- crosstalk that provided (for some tems, eagerly seek out those com- ears) a wonderfully open, wide - ponents-including special ca- stage quality. Those cartridges that bles-that they believe "naturally" were properly adjusted didn't add desirable sonic properties. In manifest that effect and were that, they resemble the food fad- therefore considered defective by many U.S. audiophiles. dists who insist that vitamin C ex- FIG. 1 tracted from rose hips has far Some critical listeners have greater virtue than vitamin C de- The factors in a home system complained that music recorded rived from chemically -produced that can influence the perceived on compact discs frequently lacks ascorbic acid. Let's look at some of spatial properties of a stereo signal depth when compared with LP's the electrical, mechanical, acous- are: accidental or deliberate phase that were made from the same tic, and psycho -acoustic factors shift between channels, channel masters.It could well be that that serve to produce an enhanced separation, out -of -phase crosstalk phase anomalies in phono car- stereo sound stage. between the channels, frequency - tridges-which are not present in response irregularities, and the CD laser pickups-are responsible The influencing factors ratio of directly perceived versus for the differences heard. Such The most dramatic influence on delayed or reflected sound within enhancing crosstalk can also oc- the perceived depth of the stereo a room. That last factor is basically cur accidentally in a component image is usually the type and determined by the designed -in through capacitive coupling on amount of reverberation in the re- dispersion of the speakers and the circuit board, or purposely cording itself. The sound field em- their placement in the listening through design. bodied in a well-miked, simply - room. And, of course, we can't ne- Frequency -response differ- mixed recording consists of three glect the speakers' interactions ences, particularly small ones, sonic components picked up by with the acoustic environment heard during critical A/B listening the microphones: the direct they find themselves in. Some of tests are frequently interpreted as sound, the early reflections, and those factors are worth some addi- differences in depth, openness, or the reverberation. The direct tional discussion. "air," rather than as tonal -balance sound, which is the first heard, is differences. For example, a small used by the ear to localize the Crosstalk bump in frequency response at source of the sound. Next, the ear- Out -of -phase crosstalk between about 300 Hz (which is where the ly room reflections contribute a channels, whether introduced de- reverberant energy in a recording sense of the size of the acoustic liberately or otherwise, will de- is concentrated) may contribute to space. When the late -arriving re- emphasize the center -recorded subjectively -enhanced depth. And flections become numerous, they sounds, thus increasing the depth many moving -coil cartridges-and become homogenized and blend and width of the stereo stage. Be- some electronic components- into reverberation, which adds a cause crosstalk in a phono car- have had a rising high -end re- sense of warmth and continuity to tridge usually varies to some sponse that is frequently inter - the sound. degree across the audio -frequency continued on page 38

Ike.A4«kept t.,() C.J sir, 7:

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37 from two widely spaced sound AUDIO UPDATE Puta sources (speakers). Itis really no continued from page 33 wonder then that speaker engineers disagree in their design ap- testlab in preted as "airiness" and increased proaches. depth. In past columns I've described ourtool pouch. in detail how phase and level cues Hiss are used by the ear/brain mecha- Also related is the fact the a nism to localize the source of a small amount of stereo noise (ran- sound in reallife. Stereo repro- LI3.25 dom hiss) added to otherwise - duction attempts to use those clean program material can add to same psycho -acoustic cues to con- the subjective appearance of air- struct a sonic illusion, but the es- [D, iness of the stereo image. sential artificiality of the process 911 I wasn't aware of the hiss - gets in the way. Speaker designers

11111 equals -highs phenomena untilit have been manipulating speaker was brought to my attention by dispersion in a rather hit-or-miss ..A Bob Carver, many of whose de- fashion for years in an attempt to signs have shown an in-depth achieve greater realism. You will ASO awareness of psycho -acoustics. find speakers with drivers facing When, during a demonstration of every which way, including away 4 a a prototype of his "autocorrelator" from the listener, all in an effort to noise -reduction system many generate the phase, level, and ar- years ago, I complained about a rival -time cues that the ear/brain r1 slight loss of highs, he didn't seem uses to construct an acoustic im- to be surprised or upset. He sim- age. The fact that each speaker ul- ply used an external white -noise timately must operate in an generator to add a touch of hiss to acoustic environment that is un- sok nok titititsl the cleaned up signal-and the known to the speaker designer "lost" high -frequencies subjec- tremendously complicates the tively reappeared! matter. He then mentioned that there Audiophiles tend to disagree as The Fluke 8060A 41/2 -digit was early resistance to the Dolby to the "best" speakers in respect handheld multimeter. professional noise -reduction sys- to their imaging properties. As- It's the best tool you could add to your tool tem because the reduction of tape suming that none of the speakers pouch, because it lets you troubleshoot more ...with less. hiss resulted in a subjective dull- argued about are specifically de- This portable, powerful instrument has a ing of the program material. It re- signed for special properties, I unique combination of features not available cently occurred to me that some of think that the disagreements sim- in any other handheld DMM. today's complaints about the ply reflect an (usually) accidental A simple push of a button on the Fluke "closed -in" quality of CD's might fortuitous match of dispersion 8060A lets you measure frequencies to 200 also arise from their inherent lack characteristics of a particular pair kHz, make relative offset measurements, con- of background noise. of speakers, their location, and the vert voltages to direct reading decibels, or reflective characteristics of the lis- conduct audible continuity tests. Plus the Speaker spatiality tening room. Those same speak- 8060A offers wideband True RMS ac meas- As long as I can remember, there urement capability to 100 kHz. ers in a different room or location So say goodbye to your part-time counters, have been disagreements, even might not sound as good. oscilloscopes, continuity testers, calculators among equally learned and expe- In the past two or three years and power supplies. And welcome a full-time rienced speaker engineers, about two companies (Acoustic Re- professional that'll be there when you need it. the optimum radiation patterns for search and dbx) have addressed You'll find that for troubleshooting every- a home speaker. In other words, the speaker-radiation/room-en- thing from motor controls to data communica- what is the best (most realistic vironment problem from a scien- tions equipment, the Fluke 8060A is the best sounding) way for a speaker to de- tifically analyzed psycho -acoustic/ multimeter value going. liver its sounds into a room? In my acoustic perspective. The result is Find out more by calling our toll -free hot- view, the question is so difficult- a substantial enhancement of the line 1-800-227-3800, ext. 229, day or night. and provokes so many different spatial realism of several of their Outside the U.S. call 1-402-496-1350, ext. 229. answers-because of the essential systems, one of which, the dbx artificiality of the stereo -reproduc- SF -10, is shown in Fig.1. I think the FROM THE WORLD LEADER tion process. audio industry is finally getting IN DIGITAL MULTIMETERS. When I discussed the matter in around to appreciate that creating earlier columns, I pointed out that a realistic stereo illusion in a home nowhere in nature do you find the environment takes something illusion of a localized single sound more than two channels of stereo FLUKE source generated by the level and feeding a pair of conventional for- c.) phase cues in the sound coming ward -facing speakers. R -E ©1986 Fluke 38 CIRCLE 192 ON FREE INFORMATION CARD ANTIQUE RADIOS RICHARD D. FITCH Restoring a classic, part 2

LAST TIME WE LOOKED IN DETAIL AT THE chassis, we can proceed with re- schematic for one of the most pop- 0.37121 1270E2 I 280E2 0.2612 turning the radio to operating con- ular radios of its time, the GE A-53. T1 dition. But first we must make sure See Radio -Electronics, June 1987. that restoration is possible and 3E2 12E2 7.5E2 worthwhile. Following the safety As Imentioned, I've had one of 0.5E2' those units in my collection for rulesI outlined last time, the set quite a while, but have never at- 220V was plugged in and turned on. All tempted to restore it, until now. To 240V 115V of the glass envelope tubes lit ex- show how a typical restoration task cept the rectifier (5Z4). A slight might go, we'll restore that radio movement of the tube in the sock- together now. But first, let's finish FIG. I et brought that tube to life. The set up with the circuit. was one of the first to use metal - envelope octal tubes. To tell Back to the circuit whether or not those tubes were For space reasons, we were not lit required touching each one able to finish up our look at the carehilly. The touch test told me schematic in the June issue. I'll that they were lit. Despite that, rectify that problem now. Ind- only a slight hum could be heard dently, you will likely want to have emanating from the elec- that figure ("Antique Radios," June trodynamic loudspeaker. 1987, Fig. 1) handy as we proceed, I next made a few attempts to and you will certainly want it when inject a signal via the antenna ter- we turn to the restoration itself. minals and then the grid caps, but Plate and grid voltages are sup- with no luck. Changing the posi- plied by a 5Z4 rectifier tube. The tion of the toggle switch that was output of the tube is fed to 116, the added at the rear apron produced field coil. The field coil serves two 11111.11111111111 the same result. The missing band purposes: First of all, it is the loud- switch was discounted as the speaker's electromagnet (perma- FIG. 2 cause of the problem because nent magnets were not used in even if the unit had been reduced early speakers). Secondly, it works former is shown schematically in to a simple phono amp, it should as a choke, filtering the output of Fig. 1. By properly tapping the still pass a signal. the power rectifier. That was a typ- unit, output voltages from 115 to My past experience with similar ical design for the period. 240 volts were available. Again in- radios told me that a likely place to Power transformers for the GE formation indicated that my trans- look for the cause of the trouble is Model A-53 (and many other) re- former was set up for 115 volts. somewhere between the plate of ceivers require some added cau- the output tube, here a 6F6, and tion. There were three possible Troubleshooting the speaker coil.I unplugged the transformers that could have been Of course you realize that we unit to make a few continuity tests. installed in this chassis, depend- have been afforded a rare luxury The speaker was also unplugged ing on the requirements of the with this set. OftenI don't even from the chassis. My tests showed area where the set was sold. Trans- have the complete tube layout, let that the voice coil and the second- former information is usually avail- alone a schematic and the original ary winding of the output trans- able on a sticker at the rear of the factory specifications. That's one former, which on this set is located chassis. In the case of my set, in- reason the set was chosen-it under the chassis, were both fine. formation indicated that it was a made an ideal "first-time" project. At this point, we've done about universal transformer. The trans - Now that we are familiar with the all we can do without pulling the

39 chassis. That's because several Still working in the same area first tube sockets will be cleaned. The components, including the the suspected, one more continuity toggle switch and the jack will be first and second IF transformers, test located the problem: It was an removed from the rear of the chas- as well as the circuit alterations, open in the primary winding of the sis. That will leave two holes on the are located under the chassis. A output transformer. rear of the chassis, as well as z. good sign was that the chassis No, I don't have a new trans- dummy bandswitch knob on th bolts and the (remaining) front - former for that set in my stock. front of the cabinet. Just think, 50 panel knobs were firmly in place. Also, all of the suppliers were years from now some future radio That indicates to me that this set closed at that late hour. However, I restorer will get his hands on the was operable after the alterations was obsessed with getting the set set and wonder what was in all of were made, even if just as some to play that night so I went search- those holes, and what kind of kind of amplifier. Human nature, ing through my junkbox (I never modifications were made. being what itis, no one would throw any old parts away). Luckily, But he won't have to wonder for bother to tighten the bolts on I found one that was almost a per- long.I intend to attach full infor- something that was not working. fect match. mation on the set to the inside of Examining the underside of the I laid the substitute in the chas- the cabinet. Included will be de- chassis, after removal, showed sis of the GE, and clipped the wires tails on all alterations and circuit that it was clean and neatly done. I into the circuit with alligator clips changes that were made by me, didn't even need my handy can of as shown in Fig. 2. (Not forgetting, and others before me. Leaving in- insecticide. In short, there was no of course, to disconnect the origi- formation on circuit changes for obvious reason why the set nal transformer.) Crude as it looks, future servicers is an important shouldn't pass a signal. Plugging that is a very valid way to substitute habit to get into, and one that has in the speaker and the line cord, I parts for testing, and one that has been observed almost from the took a few voltage readings at the been used by nearly all service start. Don't be surprised to find output tube. That voltage didn't technicians almost from the begin- parched, hand -drawn diagrams correspond to what was indicated ning of radio. rolled up inside your antique rain the specifications (having those After making the proper con- dio. All early well -trained hob- numbers was truly a luxury), so I nections and disconnections, I byists and servicemen followed unplugged the set once again; it again plugged in the line cord and that procedure. was time for some more probing. waited. In a few minutes my efforts and frustrations were re- Some closing notes warded. The set began to play the Tube -socket terminals are one Get A Complete Course In music of the big bands, just as it of the prime causes of wiring did in the 1930's. (I tune all my an- shorts in antique radios. Wires are tique radios to the local "big dressed along their sharp edges, ELECTRONIC bands" station.) and over the years that causes breaks in the insulation. If you find ENGINEERING Finishing touches that situation, at least bend the Restoring the cabinet was no big wire away from the terminals. Or, 8 volumes, over 2000 pages, even better, you could replace the including all necessary math and problem. A few veneer patches physics. 29 examinations to help and some stain to match the wire, put a piece of spaghetti tub- you gauge your personal pro- patches to the rest of the cabinet ing over it, or coat it with some gress. A truly great learning were all that were required. There liquid high -voltage insulation. experience. were no inlays or decals to be con- Finally, in the course of our pok- Prepare now to take advan- cerned with, so the cabinet just ing around the set we discovered tage of the growing demand for got a light sanding. The sanding that a wave -trap had been installed people able to work at the engin- has to be done with extreme care, between the antenna (blue) and eering level. however. The finish layer of veneer ground (white) leads. That was Askfor our brochure giving is often no thicker that the paper done in the 1930's and indicated complete details of content. Use that this page is printed on. Once that the owner was located near a your free information card num- you sand through that finish, it's powerful telegraph station. With- ber, or write us directly. $99.95, harder to cover up than a hole. out those traps, the code signals Postage Included.Satisfaction I decided not to bother replac- would have overpowered the re- guaranteed or money refunded. ing the missing bandswitch. In its ceiver and would be heard over place an almost -matching knob the entire band. It's fairly common was bolted to the front of the cab- to find such filters on receivers of r\AAJ inet to maintain at least a look of the period. Banner authenticity. Much of the procedure we fol- Technical To finish restoring the chassis, lowed can be applied to any de- Books, Inc. the test output transformer will be pression -era radio. Of course, 1203 Grant Ave bolted in place of the original, or a things just happen to work out Rockford, IL 61103 suitable new one will be used. The better sometimes than others: I'd tubes will all be tested and all the say I lucked out on this set. R -E CIRCLE 181 ON FREE INFORMATION CARD

40 DESIGNER'S NOTEBOOK ROBERT GROSSBLATT, An under -voltage monitor CIRCUITS EDITOR

JUDGING BY THE RESPONSE I'VE GOTTEN transient drop on the unregulated to October's circuit, there are a lot +8V + 5V voltage. Those are handled by C1, of you out there who are inter- (UNREGULATED) (REGULATED) a 500-g unit that stores enough ested in ways to keep an electronic energy to supply the 7805 during eye on the state of your batteries. the transient voltage drop. When We've already seen how to watch the unregulated voltage really out for excessive voltages, so I starts to fall to zero, C1 will dis- guess it's only right to take a look charge and the voltage at the input at the other side of the coin-un- of the regulator will start sliding der-voltage indicators. ul ALARM down to zero. Once it gets below Just as itis with over -voltage Cl 6.7 volts, the Zener will shut down monitors, there are lots of ways to 50011F and the alarm output will turn on. go about des;gning a circuit to l6V The bottom line here is that if the make sure that an input voltage is alarm goes off, you can be sure greater than a particular preset val- that your circuit is in real trouble. ue. As a matter of fact, I've de- The alarm output can be used to scribed a few of them in the past. kick in emergency power, do a The reason I've decided to talk quick memory write, turn on a si- about it again this month is not ren, etc. only to show you a neat little cir- FIG. 1 Although you can use the alarm cuit, but also to demonstrate how output to trigger anything you a few small changes can let a cir- threshold voltage, the collector of want, it's a good idea to stay away cuit do two apparently opposite Q1 is kept low. If the unregulated from mechanical relays since it jobs. voltage falls below 6.7, the Zener won't be too long before you have The circuit shown in Fig. 1is will turn off and Q1's collector will no power at all. The actual time really made up of two separate sec- go high. That's 6 volts for the Zener you will have depends on the cir- tions. The first is the familiar 7805 plus the normal 0.7 -volt drop cuit you're protecting-how much regulator and the second is, well, across the transistor's emitter -base current it draws, total circuit ca- everything else. If you have a copy junction. pacitance, and so on. There will of October's column handy, you'll I've shown the circuit working in likely be enough time to take elec- find it interesting to compare the conjunction with a 7805 since it's tronic action, but most mechanical circuit there with the one shown often very convenient to detect a relays will just be too slow. By the here. The basic idea behind the power drop before it makes itself time the relay has closed, you'll be over -voltage indicator was to let known in the actual circuit.Itis out of juice, and out of luck. the Zener diode look at the voltage useful to watch the unregulated and start conducting if it exceeded voltage since there will be a finite Product of the month the Zener voltage. As soon as that time before it gets so low that the It's time to award another of our happened, the Zener would turn regulator turns off. A 7805 will con- highly coveted Silver Soldering on a transistor, making its collec- tinue to put out 5 volts as long as Iron awards. This one goes to Tele- tor go low and lighting an LED. the input voltage stays above byte Technology, Inc., of Green - The schematic in Fig. 1 uses the about 7.5 volts. The reason I've set lawn, NY, for their RS -232 Mini same design approach, but the this circuit to trip at 6.7 volts is to Analyzer Kit. See Fig. 2. It consists Zener diode is used in exactly the guard against any false triggering. of a model 43 RS -232 line monitor, opposite fashion. As long as the Heavy current demands in other a model 51 Mini Patch Box, and a voltage stays above the Zener's parts of the circuit can cause a bag of colored jumper wires. Both

41 BeanFCC units are housed in the same type of plastic hoods that are usually LICENSED used to make null modems and ELECTRONIC TECHNICIAN! gender changers. Since they each have a female DB-25 connector on one end and a male on the other, Earn up to they can easily be inserted into S30 an hour most RS -232 lines. and more! The line monitor, called the MicroPeeper, has both red and Learn at home in spare time. green LED's on lines 2-6,8, and 20. FIG.2 No previous experience1In" needed. The LED's are high -efficiency No costly school. No commuting to class. types, so they're nice and bright. MicroPeeper together gives you The Original Home -Study course pre- That is important because RS -232- complete control of the routing pares you for the "FCC Commercial Radio- level changes can be very brief and telephone License". This valuable license and testing of the entire RS -232 is your "ticket" to thousands of exciting easily can be missed if the LED's line. That is valuable when you're jobs in Communications. Radio -TV, Micro- are too dim. That is the problem trying to troubleshoot a printer wave. Computers, Radar. Avonics and with the less -expensive units that line, modem, or finding out more! You don't need a college degree to use tri-color LED's rather than sep- qualify, but you do need an FCC License. whether your computer's UART is No Need to Quit Your Job or Go To School arate red and green ones. working. This proven course is easy, fast and low The MicroPeeper has an unas- The MicroPeeper is priced at cost! GUARANTEED PASS - You get your signed pair of LED's that are tied to $49, and the Mini Patch Box lists FCCLicense or money refunded. Send for a TEST pin. That is a neat feature, for $25. If you buy them together FREEfacts now.MAIL COUPON TODAY! r since it allows you to watch any as the Mini Analyzer Kit for $74 commanD PRODUCTIO1S other line you want. The seven (model 301) you'll get a plastic car- FCC LICENSE TRAINING, Dept90 lines already monitored are the rying case and the bag of wire jum- P.O. Box 2223, San Francisco, CA 94126 most common ones, but some ap- pers as a bonus. If you shop Please rush FREE details immediately! plications use the RS -232 standard around there's no doubt you'll be NAME ADDRESS in less than standard ways. Using able to find a cheaper RS -232 ana- CITY STATE -ZIP the Mini Patch Box and the lyzer kit, but not a better one. R -E

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This IC tester tests IC's in and out o1 --and it's affordable'

SERVICING DIGITAL ELECTRONIC EQUIP- be performed, but doing so requires a high Test routines may be entered by hand ment is seldom easy; difficulties arise degree of technical knowledge, which on the tester's keyboard or downloaded from several sources. For example, mi- may not always be available. Clearly, a from any computer with an RS -232 serial croprocessors, RAM, and ROM IC's are better method is needed. port. In addition, routines entered via the usually socketed, but digital "glue" IC's The in- and out -of -circuit IC tester pre- tester's keypad may be uploaded and (gates, flip-flops, etc.) are seldom sock- sented here is such a method. It is a mod- saved for future use. Simple BASIC pro- eted, because the sockets may cost as erately priced device that can test most grams allow you to upload and download much as the IC's themselves. parts in most TTL families, as well as test routines. Those programs will appear Not using sockets reduces manufactur- TTL-compatible MOS and CMOS de- here, and will be available on the RE- ing costs, but causes nightmares for the vices. You use the device by selecting a BBS: the routines run (or can be adapted serviceperson. Often, an inexpensive as- test routine, clipping a test probe to the to run) on many computers, including sembly can be discarded and replaced for Device Under Test (DUT), and examining IBM's and clones, Radio Shack Models less than it would cost to repair it. But an LED display. III and IV, the Color Computer, Com- when a board must be fixed, the head- Other IC testers in its price range ($300 modore and Apple computers, etc. aches begin. For example, how do you for a complete kit, other configurations locate a bad IC when most or all are sol- available) require a known -good IC of the Basic features dered to the board? type to be tested for comparison; ours The tester has a 12 -key keyboard to al- One way is to remove IC's one by one, doesn't. In addition, our tester has enough low manual entry and editing of test data replacing each until the board starts func- memory to store 105 different IC test rou- and commands, and transfer of test data to tioning again. However, if two or more tines, and it has a serial interface to upload and from a personal computer. A four - IC's are bad, the difficulty of locating and download test routines. Those ca- digit sixteen -segment alphanumeric dis- them increases tremendously. Defect iso- pabilities allow a field -service technician play prompts the user to enter data and lation using logic probes, logic analyzers, to load different test set-ups depending on displays pin -by -pin test results (both ex- oscilloscopes, and other equipment can the device he or she will be servicing. pected and actual data). 43 External back-up batteries are un- the display. That IC latches the appropri- Buffer space necessary because data and programs are ate keyboard row signals and reads the Now let's talk about how test data is stored in a special non-volatile 32K -byte column signals of the keyboard, and it stored in the tester's non-volatile RAM. CMOS RAM IC. latches the digit address lines for the dis- First, each test routine takes 256 bytes of IC's are tested dynamically: inputs are play. memory. In addition to the stored rou- cycled high and low as many as forty The third custom IC (1C4, a 75499.), is tines, a separate 256 -byte buffer is used to times, according to the test routine. That used in the RS -232 I/O channel. The IC store input data_ capability allows thorough testing of diffi- decodes the port strobes and latches the Next, corresponding to the 24 test pins cult -to -test parts, including counters, flip- serial input and output data and "busy" are 24 "slots" in memory. Each slot con- flops, and registers. signals. sists of five groups; each group contains The RS -232 driver/receiver is a two bytes. That accounts for 240 bytes (24 Using the tester MAX -233, which provides the necessary x 5 x 2). An additional 16 bytes are Testing an IC out -of -circuit is straight- level conversions to and from TTL ( + 5 reserved for the part number and the forward: Simply attach the test clip and volts) and RS -232 ( ± 10 volts) levels. The number of pins. That makes a total of 256 run the appropriate test routine, which is MAX 233 has an internal charge pump bytes (240 + 16). selectable by part number. The tester then that generates the RS -232 voltages from The first byte in each group determines writes data to the device and reads back the single -ended five -volt supply. the function of the pin: input, output, in- the results for comparison. (We'll show The keyboard and display provide the determinate, or ignore. The second byte you how to generate the test data later.) An human interface. Twelve tactile -feedback constitutes test data for that pin. Each out -of -circuit IC is not connected to any keyswitches are arranged in two columns group may have a different pin function other devices, so we needn't worry about of six rows; they are scanned by the 75500 (input, output, etc.). That is useful when input pins of the DUT that might be con- (IC6). In order to provide legible operator you are testing an IC that uses the same nected to outputs of the same or another prompts, we use a DLI414 intelligent al- pins for inputs and outputs at different device, or to ground or Vcc phanumeric display.It contains built-in times (a 74LS245 octal bus transciever, To test IC's in -circuit, the tester allows storage, decoders, and drivers for its four for example.) for inputs that may be connected to out- red 16 -segment LED digits. One bit of test data is used per test puts, ground, or Vcc as follows: The test- cycle. Each cycle consists of sending a bit er's output drivers can be floated (i. e., The driver board of data to each of eight drivers in each of placed in a high -impedance state); in ad- The IC tester provides for a maximum three NE590's and NE591's, starting with dition, they have enough current drive of 24 test pins. Each test pin may serve as the lowest pin. The drivers latch those (both sourcing and sinking) to pull an an input or output; as an output, each pin signals. Then the level on each pin is read input high or low (briefly), even if itis may be forced either high or low. So, in and stored, one byte at a time, starting connected to an output. Further, you can functionally, speaking, each test pin is with the lower eight pins. The cycle is specify that the test routine ignore any connected to three IC's in the tester: an repeated seven more times, for each byte desired pin or pins. input latch, a pull -down driver, and a pull- in a group; the procedure is repeated for up driver. The outputs, of course, can be each group, for a total of 40 (5 x 8) test How it works three -stated so that the input can be read. cycles. We'll present several practical ex- All circuitry is contained on two PC As shown in Fig. 2, that DUT interface amples later. boards, which are interconnected by a circuit is implemented with nine IC's short length of ribbon cable. One board (1C7 -1C15) on the driver board, including Assembly contains the interface circuitry through three each of the NE590, the NE591, and Start assembly by procuring or making which the DUT and the on -board micro- the 74LS373. The 74LS373's are 8 -bit the printed -circuit boards. We will pres- processor communicate. The other con- data input latches; the NE590's and ent foil patterns in "PC Service next tains the microprocessor, the RAM, and NE591's are 8 -bit addressable latches month." Etch the boards and carefully the support circuitry, including a 5 -volt with open -collector and open -emitter drill the 700 ho'es. Several hundred con- regulated power supply, an RC reset net- Darlington output transistors, respec- nections are made through the board (via work, and a 2 -MHz crystal -controlled tively. The NE590's outputs pull to plated -through holes), so you will have to clock. Crystal control is required for pre- ground and the NE591's pull to Vcc. Each make these connections with short pieces cise timing of the serial communications of the NE590/I IC's has three address in- of bare wire soldered on both sides. channel. A Z80 microprocessor directs all puts and one data input. The data present As shown in Fg. 3, the display may be tester operations. at the latter is routed to the internal latch/ mounted in one of two positions, depend- A major design goal of the tester was output circuit decoded by the former ing on whether the boards are mounted in the ability to store many test routines, so a when -C3 and cE are low. a case or are allowed to "float." If you are large amount of nonvolatile storage is We connect those drivers to the pins of using a case, mount it on the foil side of provided by a DS1230 32K byte non-vol- the DUT through P3 by way of a test cable the PC board in the area outlined with atile static RAM. The lower 4K of the and a DIP header clip. There are 24 test dashed lines in the diagram. Otherwise, RAM contains the control program. connections, plus power and ground, for a mount the display on the component side The tester's schematic is shown in Fig. total of 26 pins. You can wire up different of the board in the area that is outlined 1.It uses several custom CMOS gate ar- test cables for IC's with different sizes and with solidlines. rays for various purposes. Part of IC5 (a shapes. Similarly, if you use a case, the push- 75498) provides the write -enable func- An additional ground wire in the test buttons must also mount on the foil side of tion.It decodes address lines Al2-A14 cable is terminated with a miniature clip, the board. In that case, the key legends and disables the processor's write enable which should be connected to ground on must be reversed left to right. signal whenever all three address lines are the circuit board being tested. The Vcc If you use a case, install the key - low, thus preventing corruption of the pin may be terminated in the same manner switches first. Lay the board on a flat control program. The remainder of IC5 to supply power to an IC for out -of -circuit surface, foil side up. Orient each switch so decodes the input and output strobes for testing. The tester's power supply will not that the flat sides on each is toward the the driver board and the display. supply much current for external circuitry, Z80. The keyswitches are colored dif- Another custom IC (IC6, a 75500) is so the system being tested must have its ferently: the 0-8 switches are white; the the input/output port for the keyboard and own power supply. ENTER switch,green; theSHIFTkey ('),

44 MAX233 IC3 20 IC4 5V 75498 IC5 20 5V PTSO TO DRIVER BOARD P1 5V 0 2 SOUTSIBY SOBY CTS 1819 21 OEN 75499 Vcc 1920 3 Al2WR WEVcc 1819 53 PTS1 VccVci- 6 1000vF Cl 9.5-12VAC RTS SIN C2 A13 PTSO 7 PTS2 8 16V INPUT 4 RXDSIN 17 43 SOBY STB7 1718 4 A14 PTSI 1617 9 TSTO Vcc D7 41 Fl 5 C2 IV 16 IORQ SOUT IORQ PTS2 11 TST1 D6 e_10 12 lA 6 TXD 15 5 16 15 0- AO AO SIBY 6, PTS3 13 TST2 GND C2 6 13 7 14 05 14 + 12 Al Dl Al TSTO 15 DO 16 9 7 12 13 D4 GNO IN 10 A2 DO 9 A2 TST1 12 17 DI GNDO 18 5V -1- 10 C2V - GND GND 5-0- 10 GNDRD TST2 o- D3 02 GNDGND 20 C 4 C/ RS -232 J1 ICI T T 38 A8 Z80 30 5 TXDDSR CDO 64 4039 A10A9 /AAO I '-41) - 31 R3 7 ORXD RTS0--- 8 A2 32-0, 33 IC2 1K s51111. ODTR All DS1230-104 9 RIO -- 2 412 A4 34 11 DO Vcc 28 Wh s1,11. 101-4f1 2°171 _3_31-c7ri(j) sjirbj, 5V oGND A3 -- 57 °0171 S8 S13 _L 3 A13 35 12 DI AO 10 4 QA 4 A14 A6 13 D2 Al 5H,FT0 0 S14 A15 A5 - 37 15 D3 A2 IC6 ENT 5V -4-41414- R1 ' S2 14 DO Vcc Al 36-11 16 7 75500 S9 SlO Sll 7 S12 D4 A3 1 5 6 8 22K C3 RESET 15 D1 INT 16 17 D5 A4 STB6 02 1 19 10µF 12 D2 NMI 17 15V. 18 D6 A5 5 3 D4 SROV 16v 0 0_. 5V 8 D3 WAIT 24 19 D7 A6 4 -- 4 05 SRI 17 7 04 BRED 25 26 413 3 5 D6 SR2 16 4 5V 9 D5 MREQ 19 A8Al 25- 6 07 SR3 15 11 3301/ 20MREQ R2 t -- t4 10 06 IORQ 22 RD A9 ,.24 7 SCO SR4 14 721 D6 DI DO GNO V cc I 13 22 27 21 8 SC1 SR5 13 D3 02 D7 WE A10 101-91-8r 7i 6 WR 21 -- 12 1:11.1414 CLK 23 9 - liGNO 2 -MHz CRYSTALOSCILLATOR IC17 3 26 RSTCLK GND RD 29 0-1 A14 14 GND 412All 2 -- fi 10 STB7GND GND 03 11 D5 2 D4 PTS3 SR5 SR4 Vcc 3 5 6 5V R5 5V R6 - _E 1K wv-i 1K 41 L861. 1:139013AON cr) RADIO2o -ELECTRONICSP72 C_6 I P4 FROM MAIN BOARD + 5V CS Vcc. r 5V CS Vcc 18 5V 1 CS Vcc 18 5V 3 42 3- m 2 DO CLR 2 DO CLR 17 2 DO CLR 17 5 PTS1PISO Vcc . rs.)O rn CJ) 3 DI CE 3 DI CE 16 3 DI CE 116 7 PTS2 VccVcc . Fr; 4 D2 03 4 D2 D3 15 4 D2 3 9 TSTO D6 41119 10 IC10 IC13 D7 am 5 Q0 NE591 IC7 C17 14 5 00 NE591 07 14 5 00 NE591 07 14 11 TST1 12 13 6 13 6 13 13 14 CI 0 6 01 Q6 01 Q6 01 TST2 D5 II 06 m 7 12 7 12 7 Q2 12 15 DO GND D4 16 02 05 02 05 05 11 11 17 18 0co 98 GND03 Vcc Q4 10 +5V 98 GND03 Vcc Q4 1011 4- 5V * 8 GNDQ3 Vcc 04 10 +5V 19 D3D2DI GND 20 100011F 16V C8T aCD0 CD + 5V 1 + 5V + 5V TO TEST CLIP P3 a; D4 Vcc 16 D4 Vcc 16 04 Vcc 16 D5 CLR 15 2 05 CLR 15 2 D5 CLR 15 3 ICP1 ICP24 411 4 rIC5 4 3 GOD6 IC8 D7CE 1314 3 GO06 1C11 D7CE 1314 43 Q0D6 IC14 CE 1314 5 41,ICP3 ICP 2 ICP22CP23* 86 07 0 5 01 NE590 7 12 5 01 NE590 Q7 12 5 QI NE590 07 12 9 ICP4 ICP21 10 11 11 5 6 Q2 Q6 11 6 Q2 Q6 6 02 C16 11 ICP5 ICP2O 12 0 O 7 Q5 10 7 Q3 G5 10 7 03 05 10 13 ICP6 ICPI9 14 8 03 8 9 8 15 ICP7 ICP18 16 cu GND Q4 GND Q4 GND 04 1917 ICP8ICP9 ICP16ICP17 2018 a ICP10 1CP11 ICP14ICP15 22 in + 5V 4 5V 5V 3 1 ICP12 ICP13 2624 DO Vcc 20 2 DO Vcc 20 2 DO Vcc 20 Vcc GND t 25 Dl GO 3 t o- 5 01 1:10 3 5 01 GO 5V 02 01 4 6 D2 4 7 - 6 07 01 4 4 5V 9 02 9 D3 02 9 D3 02 03 12 D4 1C9 G3 6 12 04 1C12 03 6 12 D4 1c15 Q3 6 13 15 5 74LS373 Q4 13 15 D5 74LS373 04 13 15 D5 74LS373 D4 16 D6 Q5 14 16 06 05 14 16 D6 05 14 19 D7 Q6 17 19 07 Q6 17 19 D7 G6 17 C9-C17 11 16 11 16 11 16 .1 OEEN GND Q7 10 OEEN GND G7 10 1 OEEN GND G7 10 F TEST PINS 1-8 4- 5V TEST PINS 9-16 45V TEST PINS 17-24 PARTS LIST All resistors are 1/4 -watt, 5% unless Sl otherwise noted. Cl FV-22,000 ohms R2-330 ohms C -C2- - Fit- R3-R6-1000 ohms .6 Capacitors C8-1000 µF, 16 volts, electrolytic -- R6 C2, C4-C7, C9-C17---0.1 10 volts, ceramic disc DISP1 SEE C3-10 µF. 16 volts, electrolytic IC6 TEXT IC2 IC5 PI Semiconductors ICI IC1-Z80 microprocessor IC2-DS1230-104 32K nonvolatile RAM --J IC3-MAX233 RS -232 interface R4 IC4-75499 custom decoder SI2 SII SIO IC5-75498 custom decoder 0 IC6-75500 custom decoder IC7, IC10, IC13-NE591 open -emitter S9 S7 S6 S5 R5 octal driver ElEl El IC8, IC11, IC14-NE590 open -collector R3 It IC4 octal driver S4 S3 I S8 S14 IC9, IC12, IC15-74LS373 octal latch IC17 EC ElD F2 IC16-7805 5 -volt regulator IG17-2-Mhz crystal oscillator SEE TEXT -C6- CI- D1 -1N4001 rectifier DISP1-DL1414 16 -segment decoder driver display FIG. 3-STUFF THE MAIN BOARD as shown here. Mount the display and switches S3 -S14 on the foil Other components side if you will install the tester in a case. Note that the display is oriented differently depending on F1 -1 -amp pigtail fuse whether or not the tester is installed in a case. J1 -9 -pin D connector Pt, P2-right-angle double -row 20 -pin yellow; the 5 key, red, and the 9 key, blue. minated on each end with a twenty -pin male header strips Select the proper color and install and female header. P3-right-angle double -row 26 -pin male solder one pin of each switch from the CAUTION! At this point it is possible leader strips S1-minature SPDT toggle switch solder side of the board. Then turn the to erase the control program in the CMOS S2-momentary SPST pushbutton board over and solder the remaining three RAM. For example, if there is a solder 53-S14-momentary SPST keyboard pins of each switch from the component short on the board in the right place, the switches side. Mounting the keyswitches that way write -protect function of the 75498 will T1-Transformer, 9.5 -12 -volts,1 -amp, lifts them off the board enough to protrude be defeated. Or the write enable pin on the wall -mount through the panel of the case. Now install RAM may be shorted to ground, allowing Miscellaneous: One 10 -pin, two 20 -pin the 12 -pin display socket made from a 24 - just about anything to be written to the IC. and one 26 -pin double -row female IDC pin IC socket that has been cut in half. To prevent that from happening. use an leader connectors. Two 24 -pin single- -ow female IDC header connectors. When not using a case, the keyswitches ohmmeter or continuity tester to ensure Flat ribbon cable. 16 -pin, 20 -pin and 24- are installed on the component side of the that there are no connections between the oin DIP test clips, others as desired. board and are not spaced away from the following pins and ground, Vcc, or any Note: The following are available from: board. To mount the power and reset nearby traces on the board: IC5, pins 1, 2, ALPHA Electronics Corporation, switches on the board, you'll have to en- 3, 4, and 19; IC2, pins 20, 27, and all of P.O. Box 1005, Merritt Island, Florida large the holes indicated in the parts - the address lines, and ICI pins 20, 21, and 32952-1005, (305) 453-3534: Kit of placement diagram. 22. Fix any shorts before proceeding. parts for $299.00 + $6.00 P&H. The remainder of the instructions apply Measure the output of the regulator; it ncludes all parts, punched and to both case and case -less installation. should be +5 volts, ± 0.25 volt. Assum- screened panel, case, and labeled Install the IC the sockets on the compo- ing it's correct, insert the clock module, Keys. Test cable and clips not ncluded. Completely assembled nent side of both boards next, followed by and check pin 3 for a 2-Mhz squarewave. tester for $399.00 + $6.00 P&H. the remaining components, starting with Now remove power from the board and includes test cable with 16-, 20-, and the low -profile devices. allow a minute for the filter capacitors to 24 -pin IC test clips. Partial kit, Be sure to orient the electrolytic capaci- discharge. Being careful to observe prop- Including all IC's, display, and PC tors, the diode, the clock module and the er procedures to avoid static damage to the ooards for $199.00 + $5.00 P&H. voltage regulator (IC16) correctly.Itis MOS (Z80) and CMOS (RAM, Three custom IC's (75498, 75499 and installed so that its metal tab will contact MAX233, 75498, 75499 and 75500) 75500) for $60.00 + $4.00 P&H. the foil area of the PC board. To provide IC's, install all IC's in their sockets prop- Florida customers please add 5% extra heatsink capacity, you want to slip a erly oriented. A square foil pad on the State sales tax. Canadian customers ,lease add $3.00 additional postage clip -on heatsink on the regulator. board indicates pin 1 of all IC's. Pin one of o all orders. All foreign orders add Next mount the male header strips on the display is marked with a small tri- appropriate postage for Air shipping both boards. (See Fig. 4.) Connect the angle. and insurance. power and reset switches to the board with When you're certain that all parts are 10 -inch insulated wires (or directly to the installed correctly, in the correct place, Final assembly board if you're not using a case). Connect with no pins bent under any of the IC's, Using the keyboard layout (shown in the leads of a 9 -12 -volt AC, I -amp wall - and so on, apply power again. The word Fig. 5) as a guide, label the keyswitches. mount power transformer to the board. Do COMMAND? should scroll across the dis- If you plan to use the board without a not install any IC's yet. Connect the play repeatedly. If it does, you are ready case, the arrangement of the keys must be driver board to the main board with an 8 - for final assembly. Turn power off and reversed from left to right. If you are in- inch, twenty -conductor ribbon cable ter- unplug the transformer. stalling the tester in a case, you will need

47 play: Load, Store, Send, Recv, New, Test, and Clr. The Shift key (') is always used to e perform the function associated with the upper legend on each key. For example, '6 is a "D," used to enter hexadecimal numbers. The Shift key is a toggle. The first depression causes the shift symbol (') to appear in the display; it will disappear when the Shift key is pressed again, or when any other key is pressed. Shift must be pressed each time you want to use a b shifted key function. As a rule, you should turn the tester on first, followed by the circuit to be tested. Then connect the tester's ground clip, and e. last the IC test clip. If the test clip has more pins than the IC, "bottom justify" the test clip-when testing a 14 -pin IC, for example, connect pin 8 of the clip to pin 7 of the DUT. Here's how to enter a new test routine.

bi With COMMAND? scrolling, press New. The input buffer is cleared of any previous C8 test data. (That also occurs at power up P2 and when the reset button is pressed.) ENTER PART NO.? will scroll now. You may enter between one and eight numbers FIG. 4-STUFF THE DRIVER BOARD as shown here. Mount all parts on the component side of the or letters, followed by Enter. ENTER NO. board. OF PINS? appears now. You may enter any even number between 4 and 24 in- to prepare a front panel for the display and clusive. Press Enter. TYPE? PNOI ap- switches; Fig. 6 shows a suitable layout. pears. Enter the function of pin1 by To protect the display and enhance con- D EDIT pressing In, Out, Indet, or Ignore, and trast, install a thin (0.040") plastic bezel LOAD IGNORE then the test byte in two hex digits. (We'll inside the panel opening. Then mount the show you how to create the test byte later.) two PC boards to the case. For example, 155, OAA, X (no data nec- 4.111 CLR Using a maximum of three feet of 26 - 4 5 essary), or D98. conductor flat ribbon cable, make a test TRECV SENDB3 NEW TEST After entering data for all pins (or all cable. Terminate one end with a 26 pin pins you want to enter data for) press End. female header connector. On the other The display will ask MORE OR END?. INDET 0 ENTER 7.42i, end of the cable separate the 25th and 26th Unless you wish to enter data for another IN END wires. Terminate the 25th wire ( + 5 volts) OUT test group (remember, there are five possi- with a red test clip, and the 26th wire ble), press End again to indicate you are (ground) with a black test clip. Terminate FIG. 5-LABEL THE KEYS as shown here for finished entering data. the remaining 24 wires with two I2 -pin installation in a case. Otherwise, reverse labels The Edit key allows you to back up one single -row female header connectors. from left to right. pin if you make an error after entering the Depending on your needs, you'll want three (or one if a pin is set for IGNORE) of to obtain several IC test clips with dif- the test data characters. Each time you ferent numbers of pins; 16-, 20-, and 24 - press Edit, you back up one pin. The Clear pin clips will allow you test 14- and 16-, 3l/ key works any time the tester is expecting 18- and 20-, and 24 -pin IC's easily. When a keyboard entry, and pressing that key is attaching the test clip to the cable, orient 5A functionally the same as pressing the reset button. the clip so that pin I of the cable connects t1 to pin I of the test clip. Press the Test key after all data has been If you are going to use the serial port to entered. The IC will then be tested. If it is send and receive files, connect a 10 -pin good, the display will read IC TESTS female header connector to one end of a GOOD. Otherwise, ERROR PN?? GRP? 10 -conductor ribbon cable, and a DB9 EXPIRD ???? will scroll across the dis- chassis -mount connector to the other. FIG. 6-BASIC DIMENSIONS for the front panel. play for each pin in error, showing the pin Mount the DB9 connector on the rear of number, the group, and the expected and the case. Also mount the power and reset signal. The tester requires no other signals read data. Each question mark in the pre- switches on the back of the case. Wire an to work, but your computer's serial port ceding message will be replaced by a nu- interface cable to connect the IC tester's might. On PC -compatibles, try con- meral. For example, ERROR PNOI GRP port to that of your computer. RS -232 necting DSR, CD, DTR and RI together. 01 EXPIRD 0100 would indicate a prob- ports come in many configurations, so Finally, put the case together, plug in lem with pin I in test group I; a "I" was you will have to determine which pins are the test clip cable and the power trans- read where a "0" was expected. needed for your computer. The tester former. and turn the power switch on. Next time we'll show how to send data sends and receives serial data at 1200 to and receive data from an external com- baud, no parity, 8 data bits, and 2 stop Basic test procedure puter. In addition, we'll give several spe- bits. Pin 4 (CTS) is the transmit bus \ The following commands are available cific examples of how to generate test data signal, and pin 6 (RTS) is the receive busy when COMMAND is scrolling in the dis- for various kinds of IC's. R -E L

THE BLUE BOXAND MA BELL When blue and red meant the trashing of Ma Bell

HERB FRIEDMAN. COMMUNICATIONS EDITOR

BEFORE THE BREAKUP OF AT&T, MA BELL many calls were made or who made them. missing following the break-in was the was everyone's favorite enemy. So it was No one knows for certain whether Ma Bell folder containing copies of one of the ear- not surprising that so many people lost revenues of $100, $100 -million, or $1 - liest Blue -Box designs and a Bell -System worked so hard and so successfully at billion on the Blue Box. Blue Boxes were booklet that described how subscriber perfecting various means of making free so effective at making free, untraceable billing was done by the AMA machine-a and untraceable telephone calls. Whether calls that Ma Bell didn't want anyone to booklet that Ma Bell denied ever existed; it was a Red Box used by Joe and Jane know about them, and for many years Fig.I proves otherwise. Since the AMA College to call home, or a Blue Box used denied their existence. They even went as (Automatic Message Accounting) ma- by organized crime to lay off untraceable far as strong-arming a major consumer - chine was the means whereby Ma Bell bets, the technology that provided the science magazine into killing an article eventually tracked down both the Blue finest telephone system in the world con- that had already been prepared on the and Red Boxes, we'll take time out to tained the seeds of its own destruction. Blue and Red boxes. Further, the police explain it.Besides, knowing how the The fact of the matter is that the Blue records of a major city contain a report AMA machine works will help you to Box was so effective at making untracea- concerning a break-in at the residence of better understand Blue and Red Box ble calls that there is no estimate as to how the author of that article. The only item "phone phreaking."

Who made the call? Back in the early days of the telephone, a customer's billing originated in a mechanical counting device, which was usually called a "register" or a "meter." Each subscriber's line was connected to a meter that was part of a wall of meters. The meter clicked off the message units, and once a month someone simply wrote down the meter's reading, which was later interpolated into message -unit billing for those subscriber's who were charged by the message unit. (Flat -rate subscriber's could make unlimited calls only within a designated geographic area. The meter clicked off message units for calls outside that area.) Because eventually there were too many meters to read individually, and because more subscribers started ques- tioning their monthly bills, the local telephone companies turned to photography. A photograph of a large number of meters served as an incontestable record of their a reading at a given date and time, and was FIG. 1-THE BOOKLET THAT NEVER EXISTED. Although its existence was denied. the front (a) has a much easier to convert to customer billing photograph of an AMA tape. while the back (b) has the Bell System logo. by the accounting department.

49 As you might imagine, even with pho- As a sidelight as to the secrecy sur- The Blue Box tographs billing was cumbersome and did rounding the AMA machine, someone at The Blue Box permitted free telephone not reflect the latest technical develop- Ma Bell or the local operating company calls because it used Ma Bell's own inter- ments. A meter didn't provide any indica- decided to put the squeeze on the author nal frequency -sensitive circuits. When dition of what the subscriber was doing with of the article on Blue Boxes, and reported rect long-distance dialing was introduced, the telephone, nor did it indicate how the to the Treasury Department that he was, in the crossbar equipment knew a long-dis- average subscriber made calls or the effi- fact, manufacturing them for organized tance call was being dialed by the three - ciency of the information service (how crime-the going rate in the mid 1960's digit area code. The crossbar then con- fast the operators could handle requests). was supposedly $20,000 a box. (Perhaps verted the dial pulses to the CCITT tone So the meters were replaced by the AMA Ma Bell figured the author would get the groups, shown in Table I, that are used for machine. One machine handled up to obvious message: Forget about the Blue international and trunkline signaling. 20,000 subscribers. It produced a Box and the AMA machine or you'll (Note that those do not correspond to punched tape for a 24 -hour period that spend lots of time, and much money on Touch -Tone frequencies.) As you can see showed, among other things, the time a lawyer's fees to get out of the hassles it in that table, the tone groups represent phone was picked up (went off -hook), the will cause.) The author was suddenly vis- more than just numbers; among other number dialed, the time the called party ited at his place of employment by a Trea- things there are tone groups identified as answered, and the time the originating sury agent. KP (prime) and ST (start)-keep them in phone was hung up (placed on -hook). Fortunately, it took just a few minutes to mind. One other point, which will answer convince the agent that the author was When a subscriber dialed an area code some questions that you're certain to really just that, and not a technical wizard and a telephone number on a rotary -dial think of as we discuss the Red and Blue working for the mob. But one con- telephone, the crossbar automatically boxes: Ma Bell did not want persons out- versation led to another, and the Treasury connected the subscriber's telephone to a side their system to know about the AMA long-distance trunk, converted the dial machine. The reason? Almost everyone TABLE 1-CCITT NUMERICAL CODE pulses to CCITT tones, set up electronic had complaints-usually unjustified- cross-country signaling equipment, and about their billing. Had the public been Digit Frequencies recorded the originating number and the aware of the AMA machine they would (hz) called number oil the AMA machine. The

have asked for a monthly list of their tele- 1 700 + 900 CCITT tones sent out on the long-dis- phone calls. It wasn't that Ma Bell feared 2 700 + 1100 tance trunk lines activated special equip- errors in billing; rather, they were fearful 3 900 + 1100 ment that set up or selected the routing, of being buried under an avalanche of 4 700 + 1300 and caused electro-mechanical equip- paperwork and customer complaints. 5 900 + 1300 ment in the target city to dial the called 6 1100 + 1300 Also, the public believed their telephone telephone. 7 700 + 1500 calls were personal and untraceable, and Operator -assisted long-distance calls Ma Bell didn't want to admit that they 8 900 + 1500 9 1100 +1500 worked the same way. The operator sim- knew about the who, when, and where of 0 1300 +1500 ply logged into a long-distance trunk and every call. And so Ma Bell always insisted Code 11 700 +1700}FOR INWARD pushed the appropriate buttons, which that billing was based on a meter that Code 12 900 +1700 OPERATORS generated the same tones as direct -dial simply "clicked" for each message unit; KP 1100 +1700 PRIME equipment. The button sequence was KP that there was no record, other than for (START OF (which activated the long-distance equip- long-distance calls, as to who called PULSING) ment), then the complete area code and KP2 1300 1700 TRANSIT whom. Long distance was handled by, telephone number. At the target city, the and the billing information was done by TRAFFIC ST 1500 1700 START connection was made to the called an operator, so there was a written record (END OF number but ringing did not occur until the Ma Bell could not deny. PULSING) operator there pressed the ST button. The secrecy surrounding the AMA ma- The sequence of events of early Blue chine was so pervasive that local, state, Boxes went like this: The caller dialed and even federal police were told that lo- agent was astounded to learn about the information in a distant city, which caused cal calls made by criminals were un- AMA machine. (Wow! Can an author his AMA machine to record a free call to traceable, and that people who made whose story is squelched spill his guts.) information. When the information oper- obscene telephone calls could not be According to the Treasury agent, his de- ator answered, he pressed the KP key on tracked down unless the person receiving partment had been told that it was impos- the Blue Box, which disconnected the the call could keep the caller on the line sible to get a record of local calls made by operator and gave him access to a long- for some 30 to 50 minutes so the connec- gangsters: The Treasury department had distance trunk. He then dialed the desired tions could be physically traced by techni- never been informed of the existence of number and ended with an ST, which cians. Imagine asking a woman or child to automatic message accounting. Needless caused the target phone to ring. For as put up with almost an hour's worth of the to say, the agent left with his own copy of long as the conversation took place, the most horrendous obscenities in the hope the Bell System publication about the AMA machine indicated a free call to an someone could trace the line. Yet in areas AMA machine, and the author had an information operator. The technique re- where the AMA machine had replaced the appointment with the local Treasury -Bu- quired a long-distance information oper- meters.it would have been a simple. reau director to fill him in on the AMA ator because the local operator, not being though perhaps time-consuming task, to machine. That information eventually on a lone distance trunk, was accessed track down the numbers called by any ended up with Senator Dodd, who was through local wire switching, not the telephone during a 24 -hour period. But conducting a congressional investigation CCITT tones. Ma Bell wanted the AMA machine kept as into, among other things, telephone com- secret as possible. and so many a criminal pany surveillance of subscriber lines- was not caught, and many a woman was which was a common practice for which Call anywhere harried by the obscene calls of a potential there was detailed instructions, Ma Bell's Now imagine the possibilities. Assume rapist. because existence of the AMA ma- own switching equipment ("crossbar") the Blue Box user was in Philadelphia. He chine was denied. manual. would call Chicago information, discon-

50 nect from the operator with a KP tone, AMA tape indicated a real long-distance simply monitored the booth. Ma Bell and then dial anywhere that was on direct - telephone call-perhaps costing 15 or 25 might not have known who originated the dial service: Los Angeles, Dallas, or any- cents-instead of a freebie. Of course, call, but she did know who got the call. where in the world if the Blue Boxer could that is the reason why when Ma Bell fi- and getting that party to spill their guts get the international codes. nally decided to go public with "assisted" was no problem. The legend is often told of one Blue newspaper articles about the Blue Box The mob and a few Blue Box hobbyists Boxer who, in the 1960's, lived in New users they had apprehended, it was usu- (maybe even thousands) knew of the York and had a girl friend at a college near ally about some college kid or "phone AMA machine, and so they used a real Boston. Now back in the 1960's, making a phreak." One never read of a mobster telephone number for the KP skip. Their telephone call to a college town on the being caught. Greed and stupidity were AMA tapes looked perfectly legitimate. weekend was even more difficult than it is the reasons why the kid's were caught. Even if Ma Bell had told the authorities today to make a call from New York to It was the transistor that led to Ma Bell they could provide a list of direct -dialed Florida on a reduced -rate holiday using going public with the Blue Box. By using calls made by local mobsters, the AMA one of the cut-rate long-distance carriers. transistors and RC phase -shift networks tapes would never show who was called So our Blue Boxer got on an international for the oscillators, a portable Blue Box through a Blue Box. For example. if a operator's circuit to Rome, Blue Boxed could be made inexpensively, and small bookmaker in New York wanted to lay off through to a Hamburg operator, and asked enough to be to be used unobtrusively some action in Chicago, he could make a Hamburg to patch through to Boston. The from a public telephone. The college legitimate call to a phone in New Jersey Hamburg operator thought the call ori- crowd in many technical schools went and then Blue Box to Chicago. His AMA ginated in Rome and inquired as to the crazy with the portable Blue Box; they tape would show a call to New Jersey. "operator's" good English, to which the could call the folks back home, their Nowhere would there be a record of the Blue Boxer replied that he was an expatri- friends, or get on a free network (the Al- call to Chicago. Of course, automatic ate hired to handle calls by American tour- berta and Carolina connections-which tone monitoring, computerized billing. ists back to their homeland. Every could be a topic for a whole separate arti- and ESS (Electronic Switching Systems) weekend, while the Northeast was stran- cle) and never pay a dime to Ma Bell. now makes that all virtually impossible. gled by reduced -rate long-distance calls, our Blue Boxer had no trouble sending his SPKR1 voice almost 7,000 miles for free. SI S2 Vacuum tubes Assembly plans for Blue Boxes were sold through classified advertisements in the electronic -hobbyist magazines. One of the earliest designs was a two -tube portable model that used a 1.5 -volt "A" battery for the filaments and a 125 -volt "B" VI V2 battery for the high -voltage (B +) power supply. The portable Blue Box's functional circuit is shown in Fig. 2. It con- sisted of two phase -shift oscillators sharing a common speaker that mixed the tones from both oscillators. Switches SI and S2 each represent 12 switching cir- FIG. 2-A POPULAR BLUE BOX DESIGNused two phase -shift oscillators. vacuum tubes, and a simple cuits used to generate the tones. (No, we speaker connection that mixed both oscillators into a single two-tone output. will not supply a working circuit, so please don't write in and ask-Editor.) Unlike the mobsters who were willing to but that's the way it was. The user placed the speaker over the tele- pay a small long-distance charge when You might wonder how Ma Bell dis- phone handset's transmitter and simply Blue Boxing. the kids wanted it, wanted it covered the tricks of the Blue Boxers. pressed the buttons that corresponded to all free, and so they used the information Simple, they hired the perpetrators as the desired CCITT tones. It was just that operator routing, and would often talk consultants. While the initial newspaper simple. "free -of -charge" for hours on end. articles detailed the potential jail penalties Actually, it was even easier than it reads Ma Bell finally realized that Blue Box- for apprehended Blue Boxers, except for because Blue Boxers discovered they did ing was costing them Big Bucks, and de- Ma Bell employees who assisted a Blue not need the operator. If they dialed an cided a few articles on the criminal Boxer, it is almost impossible to find an active telephone located in certain nearby, penalties might scare the Blue Boxers article on the resolution of the cases be- but different, area codes, they could Blue enough to cease and desist. But who did cause most hobbyist Blue Boxers got sus- Box just as if they had Blue Boxed Ma Bell catch? The college kids and the pended sentences and/or probation if they through an information operator's circuit. greedies. When Ma Bell decided to catch assisted Ma Bell in developing anti -Blue The subscriber whose line was Blue the Blue Boxers she simply examined the Box techniques. It is asserted, although it Boxed simply found his phone was dead AMA tapes for calls to an information can't be easily proven, that cooperating when it was picked up. But if the Blue Box operator that were excessively long. No ex -Blue Boxers were paid as consultants. conversation was short, the "dead" phone one talked to an operator for 5, 10, 30 (If you can't beat them, hire them to work suddenly came to life the next time it was minutes, or several hours. Once a long for you.) picked up. Using a list of "distant" num- call to an operator appeared several times Should you get any ideas about Blue bers, a Blue Boxer would never hassle on an AMA tape, Ma Bell simply Boxing, keep in mind that modern anyone enough time to make them com- monitored the line and the Blue Boxer switching equipment has the capacity to plain to the telephone company. was caught. (Now do you understand why recognize unauthorized tones. It's the rea- The difference between Blue Boxing we opened with an explanation of the son why a local office can leave their off of a subscriber rather than an informa- AMA machine?) If the Blue Boxer subscriber Touch -Tone circuits active, al- tion operator was that the Blue Boxer's worked from a telephone booth, Ma Bell most inviting you to use the Touch -Tone

51 service. A few days after you use an un- tional schematic of a telephone. Switch authorized Touch -Tone service, the busi- SI is the hook switch. When SI is open ness office will call and inquire whether (on -hook) only the ringer circuit consist- you'd like to pay for the service or have it ing of CI and BELLI is connected across disconnected. The very same central -of- the line. Capacitor CI really has no pur- fice equipment that knows you're using pose in the ringing circuit; it only serves to Touch -Tone frequencies knows if your line keep DC from flowing through BELLI. is originating CCITT signals. When the local telephone office feeds a 20-pps ringing signal into the line it flows The Red Box through CI and a ringer coil in BELLI. A The Red Box was primarily used by the vibrating device attached to BELLI college crowd to avoid charges when fre- strikes a small bell-the ringing device. quent calls were made between two par- When the phone is answered by lifting the ticular locations, say the college and a handset from its cradle, switch SI closes student's home. Unlike the somewhat (goes off -hook) and connects the handset complex circuitry of a Blue Box, a Red across the telephone line. Since the hand- Box was nothing more than a modified set's receiver and transmitter (micro- telephone; in some instances nothing phone) are connected in series, a DC path more than a capacitor, a momentary is established from one side of the line to switch, and a battery. the other-what is called completing a As you recall from our discussion of the DC loop with the central office. The DC Blue Box, a telephone circuit is really current flowing in the loop causes the cen- established before the target phone ever tral office to instantly stop the ringing rings, and the circuit is capable of carry- signal. When the handset is replaced in its ing an AC signal in either direction. When cradle, SI is opened, the DC loop is the caller hears the ringing in his or her broken, the circuit is cleared, and a signal handset, nothing is happening at the re- is sent to the originating telephone's ceiving end because the ringing signal he AMA machine that the called party has A hears is really a tone generator at his local disconnected.

telephone office. The target (called) tele- Now as we said earlier, the circuit cart TO phone actually gets its 20 pulses -per -sec- actually carry AC before the DC loop is LINE ond ringing voltage when the person who closed. The Red Box is simply a device dialed hears nothing-in the "dead" that provides a telephone with a local bat- FIG. 4-A SIMPLIFIED RED BOX. Switch S2 lifts the handset from the telephone line and con- spaces between hearing the ringing tone. tery so that the phone can generate an AC nects two D -cells as a local power supply. The When the called phone is answered and signal without having a DC connection to circuit is DC -isolated from the telephone line taken off hook, the telephone completes a the telephone line. The earliest of the Red even when hook switch S1 is closed. local -office DC loop that is the signal to Boxes was the surplus military field tele- stop the ringing voltage. About three sec- phone, of which there were thousands through S2 -a to S2 -b, through TI's pri- onds later the DC loop results in a signal upon thousands in the marketplace during mary (P), through the handset, through being sent all the way back to the caller's the 1950's and 1960's, The field telephone S2 -c, to line B. There is a complete DC AMA machine that the called telephone was a portable telephone unit having a path across the line, and if the unit is was answered. Keep that three -second manual ringer worked by a crank-just connected across a conventional subscrib- AMA delay in mind. (By now you should like the telephone Grandpa used on the er telephone line it will close the DC loop have a pretty good idea of what's coming!) farm-and two D -cells. A selector switch from the local office. Figure 3 shows the simplified func- set up the unit so that it functioned as a To use the field telephone as a Red Box, standard telephone that could be con- switch S2 is set to L (LocAL). Switches nected to a combat switchboard, with the S2 -b and S2 -c connect batteries BI and DC power supplied by the switchboard. B2 in series with the handset and the But if a combat unit wasn't connected to a transformer's primary, which constitute switchboard, and the Lieutenant yelled an active, working telephone circuit. "Take a wire," the signalman threw a Switch S2 -a connects T2's secondary to switch on his field telephone that switch- one side of the telephone line through a ed in the local batteries. To prevent the non -polarized capacitor (CI), so that possibility of having both ends of the cir- when hook -switch SI is closed, TI's sec- cuit feeding battery current into the line in ondary cannot close the DC loop. opposite polarity-thereby resulting in silence-the output from the field tele- Press once to talk phone when running from its internal The Red Box was used at the receiving batteries was only the AC representing the end; let's assume it's the old homestead. voice input, not modulated DC. The call was originated by Junior (or Sis) Figure 4 is the functional simplified at their college 1000 miles from home. Joe schematic for a field telephone (do not gave the family one ring and then hung up, attempt to build that circuit). Momen- which told them that he's calling. Pop set tary switch S4 is not part of the field up the Red Box by setting S2 to LOCAL. telephone, it is added when the phone is Then Junior redialed the old homestead. converted to a Red Box; so for now, con- Pop lifted the handset when the phone FIG. 3-A SIMPLIFIED TELEPHONE circuit. The sider that S4 does not exist. Once again. rang, which closed SI. Then Pop closed handset is connected across the line when hook switch Si is closed. The handset closes the DC SI is the hook switch. When S2 is set to N momentary -switch S4 for about a half - loop with the telephone company's switching (NORMAL) and Si is closed, DC flows second, which caused the local telephone equipment. from line A through TI's secondary (S). continued on page 129

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DESCRAMBLER ARTICLE PARTS

February 1984 Issue February 1987 Issue We stock the parts, PC Board and AC We stock the parts, PC Board and AC Adaptor for an article on building a cable TV Adaptor for an article on a tri-mode cable TV descrambler appearing in Radio -Electronics. descrambler appearing in Radio -Electronics.

#701 Parts Package* $29.00 #301 Parts Package* $39.00 Includes all the original resistors, capacitors, Includes all the original resistors, capacitors, diodes, transistors, integrated circuits, coils, diodes, potentiometers, transistors, IF transformers (Toko BKAN-K5552AXX). integrated circuits, LED's, Toko coil (E52OHN-3000023) and Plessey Saw Filter #702 PC Board* $8.95 (SY-323). Original etched and drilled silk-screened PC #302 PC Board* $8.95 Board used in the article. Original 5 x 8.8 etched and drilled silk- #704 AC Adaptor $7.95 screened PC Board used in the article. Original (14 volts DC @ 285 ma) AC Adaptor #304 AC Adaptor $7.95 used in the article. Original (14 to 18 volt DC @ 200 ma) AC FREE reprint with Purchase Above Adaptor used in article. Free Reprint with Purchase Above #708 Toko Coil Set $6.95 Includes (2) BKAN-K5552AXX, (1) E520HN- #308 Plessey & Toko Set $6.95 300023, (1) 144LY-120K and BFQ-85 Includes (1) Plessey SY323 Saw Filter plus Replacement 2SC2369. (1) Toko E52OHN-300023 Coil.

Add $2.50 Shipping & Handling; $4.50 Canadian Orders

72 -CHANNEL MC -702 CONVERTER CABLE CONVERTER $79.95 WITH INFRA -RED REMOTE CONTROL 72 -channel capability Parental control for all channels Wireless, Infra -Red remote control Last channel recall

S.S= Channel output 2 or 3 switchable Fine tune memory Microprocessor controlled PLL UL listed/FCC approved operation Simple installation with any TV Skip channel memory eliminates Includes battery and 3 foot coax Add $3.50 Shipping and Handling unused channels cable $4.50 on Canadian Orders ORDER TOLL FREE W 1-800-227-8529 Inside MA: 617-695-8699 ELECTROCIICS,ItIC. VISA, MASTERCARD OR C.O.D. _ MEMBER P.O.BOX 800 MANSFIELD, MA 02048 :MIT. 'Not available to Massachusetts residents due to state law "copyright 1987 by J&W Electronics. Inc CIRCLE 65 ON FREE INFORMATION CARD 56 ,44, / .4. SURFACE MOUNT TECHNOLOGY

59 INTRODUCTION TO SMT A new packaging technique, not a new technology, that's forever changing the way that we build electronics circuits.

65 INDUSTRIAL SMT ASSEMBLY How manufacturers are adapting to and using SMT.

71 HAND SOLDERING Soldering SMC's is easy, once you know how!

73 SMT PROJECT: LED FLASHER An attention -grabber that's smaller than a postage stamp.

75 SMT PROJECT: LIGHT METER A bargraph light meter so tiny it can be worn as a charm.

77 SMT PROJECT: AN I -R REMOTE ON A KEYCHAIN It's so thin, it mounts inside an ID tag!

81 CONDUCTIVE INKS AND ADHESIVES Who needs solder or a PC board?

85 SMT PROJECT: A BUSINESS -CARD TONE GENERATOR Build this circuit on a piece of paper.

FORREST MARION A

7 Jews

58 Surface -mount technology ks .literally changing the shape of electronics manufacturing and packaging. Introduction to SMT FORREST M. MIMS, III

THE COMPACT SIZE OF MICROCASSETTE RECORDERS, CAM- U tJ corders, and credit-card size calculators and radios is not a I Pt Lit result of radically new solid-state developments. Rather, those amazingly tiny personal electronic devices are made possible by a clever electronic component packaging and assembly means knownas surface mount technology. In Surface Mount Technology, or SMT, both components and conductive traces are installed on the same side of a substrate or surface. Many kinds of substrates can be used, including ceramic, paper, plastic, and both rigid and flexible printed -circuit boards. Though components used for conventional through -hole circuit board assembly can be modified for SMT, the vast majority of SMT components, like those shown in Fig. 1, are considerably smaller than their conventional through -hole FIG. 1-SURFACE-MOUNTABLE COMPONENTS are supplied in a wide counterparts. That means that a circuit assembled with SMT range of min ature packag a. types. components is much more compact than an identical circuit assembled with conventional components. hearing aids. Many of the components and techniques used in Surprising as it may seem, SMT is not a new technology. the well established field of hybrid microcircuits are used in Its roots can be traced to the development of miniature circuit SMT. assemblies in the United States during World War 1I. Similar Though SMT has a history at least 30 years long, only in techniques were applied to the assembly of circuit boards for the past decade has it made major inroads in consumer

59 electronics. In coming years SMT will impact virtually everyone whose career or avocation is electronics. Those who PROTECTIVE GLASS OVERCOAT choose not to become familiar with SMT do so at their own EXTERNAL peril, for SMT will inevitably replace most conventional ELECTRODE circuit assembly methods during the 1990's. (SOLDER) Of course, none of that is news to the electronics technicians who service the personal electronic products mentioned above as well as electronically -controlled 35 -mm cameras, pocket and laptop computers, and a host of other products. CERAMIC / INTERNAL ELECTRODE F.7.77,71 They have learned, sometimes the hard way, that trou- SUBSTRATE RESISTOR SECONDARY ELECTRODE =2 bleshooting and repairing SMT circuitry requires different FIG. 3-INSIDE A LEADLESS CHIP RESISTOR. The construction is identi- techniques and tools than those used with conventional cal to a that of a t lick -film resistor deposited directly onto a ceramic substrate. through -hole circuits. Engineers, product managers, and entrepreneurs have found that surface -mount technology offers a vitally important means for competing with off -shore electronics manufacturers. Moreover, the economics of SMT are such that circuits can often be produced on -shore using automated production equipment for less money than having them built off -shore. Finally, SMT provides electronics experimenters and inventors with unprecedented miniaturization capabilities. The proverbial "garage inventor" can now produce functional prototype circuits every bit as tiny as the personal -electronic products popularized by the Japanese; and he can produce an SMT circuit in the same time required to produce a conventional circuit.

FIG. 4-A STRIP OF CHIP RESISTORS supplied on tape. The pencil point Advantages of SMT In the photograph Is shown for scale. The advantages of SMT that we've outlined so far are only some of the reasons the electronics industry is moving so DIP's. The area of the original board was 152.5 square inches rapidly to SMT. Here is a brief discussion of each of the while the area of the SMT version was 62.4 square inches, or advantages of SMT: only 41 percent of the area of the original board. Ray Prasad, the SMT Program Manager at Intel Corporation, has observed that a 4- x 4 -inch board containing half a megabyte of 256K DRAM memory DIP's can contain a full megabyte of surface -mountable DRAM's. If both sides of the board are used, the board can hold 2 megabytes. SMC's are considerably lighter than their through -hole counterparts. For example, the 8 -pin DIP version of National Semiconductor's popular LM308M operational amplifier weighs 600 milligrams. The SO (Small Outline) version of the same IC weighs only 60 milligrams. The low weight of FIG. 2-SMT CAN REDUCE the area of circuit boards. This small Texas Instruments' memory module is made from four SMT 64K 1 RAM's and SMC's and the smaller circuit boards they require combine to four chip capacitors. give typical SMT boards a 5 -to -1 weight advantage over conventional boards. Furthermore, the very low profile of Reduced Circuit -Board Size-The compact size of Sur- SMC's keeps SMT boards very thin and gives them as much face -Mountable Components (SMC's) can substantially re- as an 8 -to -1 volume advantage over conventional boards. duce the area of circuit boards. Figure 2, for example, shows SMT boards are not necessarily used only in highly mini- a miniature Texas Instruments SIP (Single /n -line Package) aturized products. Consider, for example, the coming gener- 64K x 4 memory module made from four 64K x I RAM's ation of small footprint desktop computers. Those machines and four chip capacitors. will be made possible by 3.5 -inch disk drives and SMT. As Texas Instruments and other manufacturers have found that for add-on peripheral cards, two or more SMT cards will fit in an SMT memory board requires from 30 to 60 percent of the the same space required by a conventional board. area required by an equivalent board assembled with con- Double -Sided Circuit Boards-Conventional circuits ventional through -hole DIP (Dual /n -line Package) inte- are often installed on boards that have printed or etched grated circuits. A surface -mountable SOT -23 transistor wiring on both sides. Plated -through holes provide intercon- occupies only a tenth of the board space of a .conventional nections between the two sides of the board. TO -92 transistor package. A 44 -pin surface -mountable PCC SMT can also make use of double -sided boards but with a (Plastic Chip Carrier) integrated -circuit package occupies new twist. Components can be installed onbothsides of an only 27.5 percent of the board space required by a standard SMT board, thereby greatly increasing the savings in space 40 -pin DIP. over boards assembled with conventional components. Since A few years ago, TI engineers made an SMT memory many SMC's have a much lower profile than conventional hoard that had been previously assembled with standard components, an SMT board having components onboth

60 Surface -Mount rapidly in recent years, but SMC's generally cost more than CD EXTERNAL their through -hole counterparts. Nevertheless, SMT can re- ELECTRODE duce overall board cost for a variety of reasons. According to (SOLDER) National Semiconductor, for instance, a savings of up to 40 percent results from the elimination of drilled holes required for conventional -component leads and pins and the reduction of plated -through holes and conductive trace layers in multi - layer boards. CERAMIC INTERLEAVED SUBSTRATE ELECTRODES/DIELECTRIC Other Advantages-Some advantages of SMT are less obvious than those listed above. For instance, the compact FIG. 5-INSIDE A CERAMIC CHIP CAPACITOR. The device is a sandwich of interleaved metal film and dielectric layers. size of SMT boards can significantly improve a waveform's rise and fall times, and reduce crosstalk in high-performance logic systems. Those advantages are a result of shorter current MONOLITHIC CERAMIC CHIP CAPACITORS paths and reduced pin -to -pin capacitance and mutual inductance. Finally, there is the undeniable advantage that SMT is X7R BX the wave of the future. Those firms that adopt SMT today will COG (NPO) be better prepared to compete tomorrow. 0805 1206 1210 1808 '812 1825 Disadvantages of SMT hEt HARRIER SOLDER TAPE AND REEL LASER MARKS Since SMT will eventually become the dominant circuit - AYE R COATING assembly technology, it's important to fully understand its aytJt' limitations and drawbacks. They include: The SMT Learning Curve-Before the advantages of FIG. 6-CHIP CAPACITORS, like these from American Precision Industries, SMT can be realized, the new SMT user, whether a large come in a variety of sizes and values. corporation or a home experimenter, must fully understand the many pitfalls that can trap the unwary. Some companies have learned about the pitfalls of SMT the hard way. They committed to manufacturing a new product using SMT before Witows-- fully understanding the potential problems. Whether through overconfidence or ignorance, the end result in several such cases has been a very costly disaster. It's important to keep the FIG. 7-SMT INDUCTORS are available in values that range from a few tens principle of the SMT learning you of nanohenries to one millihenry. review the rest of the drawbacks. SMC Standardization-As recently as 1983, only sides can be thinner than a board assembled with con- around 300 specific SMC's were available in the United ventional components. States. According to Bourns, Inc., by the end of 1986 some Subminiature Circuits-SMT is a spinoff of hybrid mi- 15,000 specific SMC's were available. While that increase crocircuit technology, and some SMT circuits are nearly as has helped spur the rapid growth of SMT, it has been accom- tiny as their hybrid cousins. Moreover, subminiature SMT panied by standardization problems. Supposedly identical circuits are considerably cheaper than hybrid circuits and components, especially semiconductors, made by different prototypes can be assembled in as little as a day using inex- manufacturers may have slightly different dimensions. In pensive assembly tools. Now engineers, technicians, and view of the close tolerances required for SMT circuit -board experimenters can assemble tiny circuits on a low budget and design, dimensional compatibility is an essential require- without special facilities. ment. Even when identically configured components are Automated Assembly-Conventional through -hole com- available from two or more manufacturers, each company ponents can be installed on circuit boards by means of may package its SMC's for different automated assembly automated assembly machines. SMT, however, is much more formats. The SMT industry recognizes the standardization compatible with automated assembly equipment. Unless the problem and is working toward solutions. Meanwhile, engi- board includes plated -through holes, the time-consuming neers and parts buyers for companies entering SMT for the chore of drilling holes in the circuit board is eliminated. first time are often surprised by the lack of standardization SMC's have no wire leads to cut, bend, and insert. For those that currently exists. and other reasons, SMT boards can be automatically as- SMC Availability-While some 15,000 components may sembled much more quickly than conventional boards using be available as SMC's, not all of theM may be available when through -hole components. needed. The author's experience has been that ordering Although automated pick -and -place SMT assembly equip- SMC's from major electronics distributors can be trying. It's ment is expensive, it's also very fast. At the low end are particularly frustrating to order an assortment of sub- machines that pick and place up to several thousand SMC's miniature SO integrated circuits and receive a package of per hour. Faster machines can pick and place from 15.000 to monster DIP's having the same part numbers. It is extremely 20,000 SMC's per hour. Sophisticated multihead pick -and - important that before committing to an SMT product, man- place machines can operate at rates exceeding 500,000 ufacturers find one or more reliable sources for the compo- SMC's per hour. Automated assembly, the chief driving force nents. And care must be taken to be sure that the supplied behind the rapid acceptance of SMT, will be covered in more components will be identically packaged and both func- detail in the next article. tionally and dimensionally equivalent. Lower Cost-The cost of individual SMC's has fallen High Start -Up Expense-The start-up cost of SMT for

61 SOT 23 SOT 143 sticky paste, are soldered to the pads when the board is heated in a convection oven, in a vapor -phase chamber, or by infrared lamps. Some SMC's are connected in place with conductive adhesives. SMT soldering methods, including their advantages and drawbacks, will be discussed in detail elsewhere in this section. Suffice it to say that a careful understanding of whichever soldering method is selected is crucial to the production of functioning, reliable SMT circuits. In the final analysis, nothing replaces practical, hands- on experience. Troubleshooting and Repair-The best way to fully appreciate the differences between conventional and SMT circuitry is to take a peek inside a handheld video camcorder.

BOTTOM The optics, focusing motor, gears, and image sensor of the TOP VIEW VIEW, typical camcorder are virtually surrounded by thin circuit I boards that are peppered with hundreds of tiny SMC's. The sight of those boards will provide convincing proof that servicing SMT circuits requires a completely different set of tools and skills than those that are required to service con- FIG. 8-FOUR MAJOR SO package outlines. ventional through -hole circuits. Since most SMC's are very closely spaced and do not have leads, conventional test instrument probes may not be suitable. Fortunately several companies now make a variety of probes and clips specifically intended for connection to SMC's. Desoldering and resoldering SMC's requires specially shaped soldering iron tips that permit all the terminals of an SMC to be simultaneously heated. Hot air desoldering and soldering tools can also be used for that purpose if care is taken to avoid inadvertent desoldering of nearby SMC's. In short, servicing SMT circuits requires new skills and much more attention to detail than the servicing of conventional through -hole circuits. The observation about the vital role of practical, hands-on experience given in the discussion of soldering surface -mountable components applies equally well to servicing SMT circuits. Other Drawbacks-Some of the pitfalls awaiting new SMT designers are less obvious than those discussed so far. Thermal overload is a good example. Since surface -mountable semiconductors are so small, they dissipate less heat than FIG. 9-A TO -92 TRANSISTOR dwarfs its SOT -23 counterparts. their conventional counterparts. That, and the fact many such devices can be densely packed together on a compact circuit both manufacturers and individual experimenters can be board, can lead to unanticipated thermal -overload problems high. For manufacturers, automated production equipment is in your designs. by far the most expensive investment. Experimenters face the Another drawback is that SMT boards require tighter di- problem of acquiring new assembly tools and a stock of mensional tolerances than conventional through -hole surface -mountable resistors, capacitors, LED's, diodes, tran- boards. In addition, board designers and draftsmen must sistors, and integrated circuits. While the cost of an individu- become acquainted with the configuration of the many dif- al SMT project may be only slightly higher than the same ferent kinds of SMC's. Computer -aided drafting software project assembled with through -hole components, acquiring may have to be updated or even replaced if it doesn't include a sufficient stock of SMT components can easily cost a few an SMT capability. hundred dollars or more. That situation will change when retail and mail-order electronics dealers begin offering kits of Surface -mountable components SMC's. Many, but not all, through -hole components have a sur- Soldering-The components of virtually all manufactured face -mountable counterpart. Physical limitations often pre- through -hole circuit boards are wave soldered. A variety of vent a conventional component from being manufactured as soldering options, each with various advantages and disad- an SMC. For example, high -capacity capacitors and power vantages, is available to the SMT user. They include single - transformers are simply too large. And the pinouts and chip and double -wave soldering, and reflow soldering. Wave sol- dimensions of some 1C's don't readily lend themselves to dering requires that the SMC's be attached to the circuit board standard surface -mount packages. Nevertheless, most cir- with a droplet of non-conductive adhesive. Reflow soldering cuits can be assembled using SMT, even if some conventional involves the use of solder paste or cream. The paste is through -hole components are required. screened over the SMC footprints or pads, or applied directly It's important for SMT circuit designers, draftsmen, and to the pads with either an automated or a hand operated service technicians to be aware of the general physical config- syringe. The terminals of the SMC's, which adhere to the urations and operating parameters of the various families of

62 Surface -Mount Chip resistors Chip resistors are the most widely produced of all SMC, es Originally developed for use in hybrid microcircuits, chip resistor technology was well established when SMT adopted for consumer and industrial products. Figure 3 shows the cross section of a typical leadless chip C:toi resistor. The construction of the device is identical to that of a thick -film resistor deposited directly on the ceramic substrate of a hybrid microcircuit. The nickel barrier between the inner 1f5. electrode and the solder coating prevents the electrode from11;c leaching during soldering. Without the nickel barrier, leach ing may impair the connection between the chip resistor and the external circuit. Figure 4 shows the very small size of chip resistors. The taped resistors in the photo are classified as 1206, a type designation indicating a physical size of 1.6 x 3.2 milli- FIG. 10 -TWO SO INTEGRATED CIRCUITS and a conventional 8 -pin mini - meters. Other types are the 0805 (1.4X2.0 mm) and 1210 DIP. (2.6 x 3.2 mm). The resistance range of most chip resistors is 10 ohms to 2.2 megohms. Some companies offer values up 4.88-0.13 to 10 megohms and even higher. 0.10 (0.1924 0.005 Trimmers and potentiometers - 0.004 Both single- and multi -turn trimming potentiometers are available in surface -mountable configurations. They are

8 7 6 5 made from ceramic or high -temperature plastics to protect them from the heat of immersion soldering. The smallest 3.91 ± 0.10 (0.154 ± 0.004) single -turn trimmers measure less than 4 x 4 millimeters. 5.99 ± 0.20 Multi -turn trimmers, which closely resemble their through - (0.236 ± 0.008) 1 1 2 3 4 hole counterparts, measure 6.35 x 6.35 mm (0.25 inch) or 8.9 x 8.9 mm (0.35 inch). Although surface -mountable trimmers are adjustable, it's a important to realize that most of those devices are not designed for repeated adjustments. A typical trimmer, for ex- 1.55 ±7 0.20 TOTAL HEIGHT 10.006 ± 0.008) ABOVE BOARD ample, might be rated for no more than 10 adjustment cycles. Another consideration is the adjustment mechanism itself. Most trimmers are designed to be adjusted by means of a miniature screwdriver or special tool. The required slot or slots may not be compatible with all kinds of automated pick - t and -place equipment. Also, trimmers that require a special 0.15-'0.05 10.006 .t0.0021 adjustment tool can pose a major problem when only a 1.27 screwdriver is available. (0.050) CLEARANCE BETWEEN PACKAGE TYPICAL BOTTOM AND BOARD Chip capacitors b Like chip resistors, leadless chip capacitors were de- 4.90 ± 0.30 veloped originally for use in hybrid microcircuits. There are 0.0121-" three principle categories of surface -mountable chip capacitors: multilayer ceramic, electrolytic, and tantalum. Four out of five chip capacitors are ceramic multilayer devices. As shown in Fig. 5, a ceramic chip capacitor is a sandwich of interleaved layers of metal film and ceramic dielectric. At 0.81 t 0.30 opposite ends of the chip, every other metal layer is intercon- 10.032t.0.012)--./L nected by an external metal electrode. Often a nickel layer is added to prevent leaching of the internal metal layers. FIG. 11 -TOP VIEW (a), side view (b), and front view (c) of a Texas Instru- Ceramic chip capacitors, like the ones in Fig. 6, are ments 8 -pin SO integrated circuit. rugged, very stable, and highly reliable. Capacitance values ranging fromI pF to 1µF are available. Package styles SMC's. What follows is a quick tour of the most important identical to those of chip resistors described above (0805 and families of SMC's. All SMC's in those families are available 1206) are available, as are larger packages. Unlike chip individually or in quantity. SMC's intended for automated resistors, the size of a chip capacitor is directly related to its assembly are supplied in reels of paper or embossed plastic value. tape, or in magazines. Some automatic assembly equipment For high capacity, electrolytic and tantalum chip capacitors is equipped with vibratory feeders that can be loaded with are available. Tantalums are available in values from 0.1 to non -packaged leadless chip components, such as resistors 100F. Aluminum electrolytics, which are larger than tan- and capacitors. talums, are available in values from around 1.5 to 47 µF.

63 of the SOT packages. The SOT -23 and SOT -143 packages are GULL WING MEAD equipped with formed leads in a gull -wing configuration. The SOT -89 leads are not formed since they emerge from the LOW -PROFILE STANDARD lower side of the package. The package configuration determines the power dissipation of any semiconductor. SOT -23 and SOT -143 devices can dissipate from 200 to 400 milliwatts. SOT -89 devices can dissipate from 500 to 10(X) mW. FIG. 12-GULL-WING VS. J -LEAD SMC packages. J -lead packages can be mounted using sockets Integrated circuits Surface -mountable integrated circuits have been available since Texas Instruments developed the gold-plated flat pack IC in the early 1960's. Today more than a dozen families of surface -mountable IC packages are in use. The most popular surface -mountable IC package, the Small -Outline (SO) configuration developed by Philips, resembles a miniature DIP. An SO device occupies around a fourth the board space of an equivalent DIP. Of even more importance is the very low profile provided by the SO package. Figure 10 shows two 8 -pin SO devices together with a conventional 8 -pin mini -DIP for a size comparison, and Fig. II is an outline view of an 8 -pin SO device. Note that the pins of SO devices are placed on 50 -mil centers rather than the 100 -mil spacing found on DIP's. While the leads of most SO devices have a gull -wing configuration, a newer design popularized by Texas Instru- ments has flat pins that bend under the IC package in a J configuration. The chips mounted on the SIP shown in Fig. 2 FIG. 13-SOT-23 DUAL -CHIP red LED's and single -chip green LED's are are J -lead devices. dwarfed by a penny. Figure 12 compares the gull wing and J -lead formats. Gull - wing devices are easier to solder and replace. They also provide sufficient flexibility to prevent the SO package from fracturing should the board be slightly bent. The J -lead devices use less space and, unlike gull wing devices, can be installed in sockets. Chips that require more than 28 pins are generally installed in square Plastic Leaded Chip Carriers (PLCC's). The PLCC uses J -shaped leads and has up to 84 or more leads around its perimeter. Many new microprocessors and other large-scale IC's are offered in PLCC's. FIG. 14-COMPONENTS SUCH AS CRYSTAL FILTERS, relays. switches. and crystals are available as SMC's. An SMC crystal is shown here. Recently, there has been considerable interest in using tape- or wire -bonded chips in SMT circuits, particularly Those capacitance ranges continue to be expanded as new those in which the pin count is high. The wire -bonding products are added. process involves cementing a chip directly to a circuit board and making connections to the chip by means of gold wire in Inductors the same manner in which connections are made between Many kinds of surface -mountable leadless and formed - chips and pins in packaged IC's. The bonded chip is then lead inductors, and even toroidal transformers, are available. protected by a small blob of epoxy. The tape bonding process, Inductance values range from a few tens of nanohenries to also known as TAB (Tape Automated Bonding), is easier to one millihenry. Figure 7 shows several surface -mountable implement because individual chips are supplied on a tape inductors. with completed electrical connections. The tape is actually a string of connected lead frames similar or identical to those Discrete semiconductors used to make packaged IC's. Epoxy protects the delicate Many diodes, transistors, and other discrete semiconduc- chips and connection leads from damage. TAB chips can be tors are available in miniature surface -mountable packages. used in automated assembly. Figure 8 shows the outlines of the four major package styles SOT -23 (Fig. 8-a), SOT -89 (Fig. 8-b), SOT -143 (Fig. 8-c), Other Surface Mountable Components and SOD -80 (Fig. 8-cl). The SOD (Small Outline Diode) In addition to the component families discussed above, package is a leadless cylinder used for diodes. The SOT there are many other surface -mountable devices. For exam- (Small Outline Transistor) packages are used for transistors, ple, many optoelectronic components are available, includ- diodes (I or 2 chips), and various optoelectronic components. ing phototransistors, optoisolators and many kinds of one - Figure 9 compares the SOT -23 transistor with its con- and two -chip infrared and visible LED's (see Fig. 13). Also ventional through -hole counterpart. available are ceramic filters, relays, switches and crystals (see Referring back to Fig. 8, note the configuration of the leads Fig. 14). R -E

64 Now that you know what SMT is all about, here's how to use and repair surface - mount components. Industrial SMT Assembly

SURFACE MOUNT TECHNOI1XlY IS FAST BECOMING AS IMPOR- tant to modem electronics as microprocessors, programmable logic arrays, and megabit RAM IC's. Microminiature surface -mountable components and the advantages and drawbacks of SMT were previously discussed. Now we'll tackle the assembly and repair of SMT circuits.

SMT assembly methods a INWINION.[ Ae.1100+1 & Irraw.n. Surface -mountable components, like conventional through - AMNIMMIIPAntione.,..S. hole components, can be placed on a board and soldered in place a either by hand or by machine. Both soldering methods fill .5.1111.110.11.1M important roles in SMT. Hand assembly is used by home experi- eatiMIWOMIN. "ALM& menters and electronics companies, the latter for the production of prototype SMT circuits. Automated assembly is used to man- COMOMMOMMI.MONOIMMINIM. ufacture SMT circuit boards.

Automated SMT assembly Automated placement equipment can select and position on a ".""*""""'""t circuit board from 1,0(X) to 500,000 components per hour. There 0111104.001 are three major categories of automatic SMC placement equip- mmaruurit ment: Mass placement, in -line pick -and -place, and x-y pick and arwearomerormormouwarlit place. FIG. 1-M CROMINIAT JRE INFRARED LED transmitter assembled by the Mass placement equipment permits many or all the SMC's in a author.

65 paste or adhesive are placed on a belt that moves under the row of pick -and -place heads. After each head places a single SMC on the board, the board advances to the next head. In -line equipment, which has long been used to produce hybrid microcircuits. is able to handle many different shapes and sizes of SMC's. And in -line machines can be set up to assemble different circuits much more rapidly than mass placement equipment is capable of. X-Y pick -and -place equipment is the most popular method for the automated assembly of SMT hoards. Two basic approaches are used. In one, a moving pick -and -place vacuum head fetches components one at a time and places them on a fixed -position hoard. In the other, the vacuum head is fixed and the board is attached to a moving x-y table that places the appropriate SMC footprint or pad directly under the head. SMC's are fed to the head by a feeder mechanism. Understanding the operation of mass placement and pick -and - place SMT assembly equipment is not the only requirement for the effective use of such machines. Automated assembly of an SMT circuit also includes provisions for automated flux application and soldering; procedures that can greatly complicate mat- FIG. 2-A U -SHAPED SOLDERING IRON tip can be used for soldering and desoldering chip resistors and capacitors. ters. Soldering of SMC's will be discussed in more detail shortly. For now. it's important to understand that automated soldering requires careful attention to hoard design and proper component placement. If the hoard is to he inverted and wave soldered, then the components must be glued to the board, a process that requires INCORRECT the careful hand or machine application of small dots of adhesive PLACEMENT at each component position. Adhesive can be hand -applied with a wire or a probe that picks up a small blob of material when it is dipped into the adhesive, or by a syringe that automatically dispenses a preset amount of adhesive. Adhesive can also be screened onto a board in a single application. In fully automated systems. the adhesive can be applied by a syringe that is mechan- ically moved to each SMC location, but automatic pin transfer is an even faster way to apply the adhesive. An array of pins that exactly matches the SMC locations is dipped in adhesive and then lightly touched to the board. When the pin array is moved CORRECT away. dots of adhesive are left behind at each SMC location. PLACEMENT All these methods require careful attention to detail. If too little adhesive is applied, the SMC may fall off when the board is

CONVEYER INVERTED PC BOARDS SOLDER FLOW

BOARD DIRECTION

FIG. 3-THE CORRECT ORIENTATION of SMC's for effective wave soldering. TURBULENT LAMINAR circuit to he simultaneously placed over adhesive dots or solder DUAL paste that was previously deposited on a circuit board. Since WAVE FLUXER PRE -HEATERS SOLDER WAVES mass placement equipment provides exceptionally fast board FIG. 4-THE DUAL -WAVE SMT soldering system. loading, it is well suited 'Or the manufacture of consumer -electronics devices. Its major drawback is that the equipment must he specially configured far specific board designs. Consequently. even minor hoard design changes can be expensive and time CHIP SMC consuming. In a typical mass -placement system, magazines loaded with SOLDER FILLET SMC's are mounted in the same orientation as the SMC's to he placed on the hoard. A vacuum head then picks tip a complete set SOLDER FILLET of SMC's. transfers them to a board and returns for another set. Bench, or in -line pick -and -place equipment. uses a vacuum pickup head to pick an individual SMC from a dispensing tape. magazine. or bin dispenser. The head then places the SMC at the proper position on the circuit hoard. A single machine may have FIG. 5-SOLDERING DEFECTS known as the drawbridge and tombstone a series of pick -and -place heads. Boards prescreened with solder effect.

66 Surface -Mount

PC BOARD soldered. If too much adhesive is applied, one or more of the solder pads may be covered, thereby preventing solder from establishing a conductive bond between the terminals of one or more SMC's and their respective pads. The delay between the application of the adhesive and the ,11111M$$ENUN, SMC's placement must be carefully controlled-the adhesive must be fresh and any solvents it contains must not attack the board or the SMC's. And, the adhesive must be properly cured HEATING before the board is soldered. ELEMENT HOT PLATE Although automated installation of SMC's receives the most

a attention, hand assembly of SMT circuits is also important since it permits prototypes to be assembled, tested, and evaluated prior to committing a board to machine production. Another important aspect of hand assembly of SMT circuits is that individuals, PC BOARD whether home experimenters or engineers in a large corporation. can quickly and easily build microminiature circuits that rival

1 If II 1 hybrid microcircuits in size and complexity. rinON$ NUENN SENNU HUNN$$ This is a remarkable capability. For example, the circuit shown in Fig.l is a miniature pulse generator circuit that drives an on- rp-cl-D-ELI board LED with high -current pulses. Although the circuit is about the size of a shirt but:on (0.3 x 0.3 inch) and is so thin it INSHISNUMMMUMNI slips easily between Iwo adjacent pins of a conventional DIP, it was assembled from scratch in about an hour using a I5 -watt soldering iron. PREHEAT ZONE REFLOW ZONE Conductive bonding INFRARED IN -LINE Though soldering is the chief method for bonding surface - mountable component and socket terminals to circuit board b pads, conductive adhesives are also used. Both methods are important, and the prospective SMT circuit designer or service technician should be familiar with each method. Conventional through -hole circuit boards are soldered either CONDENSATION 04 by hand or by passing the bottom side of a component -stuffed COILS board over a wave of molten solder. The same methods and HOT VAPOR 0 0 various kinds of reflow soldering can be used to solder SMC's 1 onto a board. Reflow soldering is a three -step process in which solder paste or cream is applied to SMC pads on a circuit board, rla_01211.1 SMC's are placed on the board, and the SMC's are heated 6 b6 simultaneously or one by one. No matter which soldering meth- -r . BOILING od is used, the heat sensitivity of the SMC's must be considered FLUORINATED PC BOARD LIQUID because SMC's having a ceramic substrate-such as chip capaci-

e, tors and chip resistors-can be permanently damaged by the HEATING COIL sudden application of the heat necessary for the solder to melt. The problems can be avoided during automated soldering by VAPOR PHASE preheating the SMC's and carefully controlling the time during which the SMC is subjected to the temperature of soldering. Thermal damage during hand soldering can be avoided by keeping the heated tip of a soldering iron from touching the center of the SMC. Instead, only the conductive terminals should be heated.

LASER HEAD Soldering Manufacturers of SMC's specify the soldering guidelines for their components; be sure to keep them in mind when consider- ing SMT soldering methods. The most important guidelines include: 1. Hand Soldering-Although most surface -mount publica- PC BOARD tions and articles relegate hand soldering to the replacement of defective SMC's, as noted earlier, hand soldering can play an important role in the assembly of prototype circuits. To meet that need, some SMC manufacturers provide detailed guidelines for the hand soldering of their components. LASER Conventional soldering irons, soldering tweezers, and hot air d soldering tools are used 10 hand solder SMC's. Soldering tweezers grip an SMC between two heated tips until soldering is FIG. 6-REFLOW SOLDERING METHODS: Hot plate reflow soldering is complete. Many different soldering iron tips are available for shown in a, infrared reflow soldering is shown in b, vapor -phase reflow soldering is shown in c, and laser reflow soldering is shown in d. The laser conventional irons, most of which permit all the terminals of an method causes the least component heating. SMC to be heated simultaneously. For example, a U-shaped (d) causes the least component heating. slotted spade tip, such as the one shown in Fig. 2, that wraps

67 wave soldering is widely used to solder SMT boards, doing so requires solving several important problems. The most crucial problem is SMC thermal shock, since all the SMC's on a wave soldered SMT board are briefly but totally immersed in molten solder. Pre -heating by means of ovens or heat lamps eliminates most danger to ceramic chip devices, while the use of high -temperature plastics protects the package integrity of both discrete and integrated semiconductors. Another drawback to wave soldering is incomplete wetting of the SMC terminals due to the shadow effect caused by adjacent, closely -spaced SMC's. That can cause cold and even missed solder joints. One way to reduce the problem is to plan the circuit board so chip components are aligned with their end terminals perpendicular to the flow of the solder wave, as shown in Fig. 3. Another way is to pass the board over two waves of solder, as shown in Fig. 4. The first wave is made purposely turbulent so that solder can reach even shadowed regions. A second, laminar wave completes the process by removing excess solder and leaving behind a clean solder fillet at every connection point. 3. Reflow Soldering-The most important conductive bonding FIG. 8-PERFECT SOLDERING of a leadless diode and a chip capacitor. method for SMC's is reflow soldering. The simplest form of reflow soldering occurs when the junction of a tinned terminal and a thickly -tinned pad is heated by a soldering iron or other

TEST POINT

BEST

FIG. 7-PERFECT SOLDERING OF AN SOT -23 TRANSISTOR. Note how the solder has flowed completely over the terminals and pads.

itself around the SMC is used to reflow solder and desolder leadless chip resistors and capacitors. Hot-air tools, which are commonly used for desoldering both SMC's and through -lead components, can also be used for hand reflow soldering. EXTENDED PAD Despite the wide variety of soldering tools designed especially for SMT, an ordinary low -wattage soldering iron having a conical ACCEPTABLE tip and 0.03 -inch or smaller rosin core wire solder can be used to b solder SMC's. Soldering is fast and reliable if the pads are tinned and if the SMC is held in place with masking tape. Hand soldering is discussed in more detail elsewhere in this special section. 2. Wave Soldering-Wave soldering is a well -established means for simultaneously soldering all the leads of through -hole components that protrude through the bottom side of a circuit hoard. Briefly, boards are machine or hand stuffed with components and placed on a moving carrier. The boards are carried, in turn, over a radiant heater, then a wave, foam or spray of rosin, and finally, a wave of molten solder. The soldered boards are usually cleaned to remove flux residue. Although the residues of rosin -based and other fluxes will cause no electrical problems if left on a board, the residues of some fluxes will cause corrosion if NO! not removed. When SMT began to become popular several years ago, it was only natural for companies to want to adapt their existing wave - FIG. 9-HOW TO USE A TEST PROBE ON AN SMC. The test probe can soldering assembly lines for soldering SMT boards. Although touch any part of the board's traces or pads, but not the chip itself.

68 Surface -Mount

board is then inverted, SMC's are placed on the second side, and heat is applied. Even though the solder on the lower side of the board may melt, the SMC's will be held securely in place by the surface tension of the molten solder. Although solder pastes and creams are widely used for reflow soldering of SMC's, they are not without disadvantages. For example, non -uniform heating during soldering or non -uniform deposition of the paste or cream can cause one end of a 2 - terminal SMC to lift off the board entirely, as shown in Fig. 5. Sometimes an SMC will actually stand completely on end. That phenomenon, which is commonly called tombstoning or draw - bridging, is caused by the surface tension of the molten solder at one terminal exceeding that at the other joint. Although a handheld soldering iron can be used to reflow solder one connection at a time, a better way-and a must for production quantity soldering-is to heat the entire board so that all the solder cream melts at the same time, thereby soldering the entire board in one step. Figure 6 shows some of the various methods for generating the heat necessary to reflow-solder entire boards in one operation, or one SMC at a time. Hot -plate reflow soldering (Fig. 6-a) is sometimes used to solder hybrid microcircuit components atop a ceramic substrate. The ceramic substrate is placed on a hot plate until the solder melts. A modified version of that process, convection -oven re - flow soldering, can be used to reflow solder production quantities of SMT boards. Boards are placed on a conveyer belt and moved over a series of hot plates arranged on an oven. One or more hot plates preheat the boards and drive off solvents present in the solder cream, while a single hot plate at a higher temperature melts the solder. The boards are then cooled by a forced -air blower. Convection -oven reflow soldering has many variations, all of which incorporate an oven through which boards loaded with SMC's ride on a moving bek. Ovens may have one or more preheating sections or chambers. Infrared reflow soldering (Fig. 6-b) is claimed by its advocates to provide a higher degree of temperature control than any reflow solder method. That's because the boards to be soldered are heated by a bank of infrared lamps whose power output can be carefully controlled. Moreover, the same lamps that gently preheat a board can also take the board to solder temperatures. The negative side of infrared reflow soldering is that dark -colored FIG. 10-A PAK-X-TRACDESOLDERING SCISSORS can be used to simultaneously heat the terminals on all four sides of a quad PLCC. SMC's, such as semiconductors and many chip components, absorb heat much more readily than their highly reflective termi- means until the two tinned layers melt and merge together. nals. Also, high profile components may block the radiation Reflow soldering can also be accomplished by placing a small, intended for other components, thereby resulting in shadow thin square of solder called a preform between a terminal and a regions containing cold or otherwise imperfect solder joints. pad. Preforms are also used to solder semiconductor chips (e.g. Vapor -phase reflow soldering (Fig. 6-c) is a clever procedure, laser diodes, LED's, transistors, etc.) to a metal header or developed by Western Electric, in which a board loaded with substrate. SMC's is placed within the hot vapor given off by a boiling Solder pastes or creams, which consist of microscopic parti- fluorinated liquid. The vapor condenses on every exposed sur- cles of solder suspended in a flux, are used for SMT reflow face of the board and its SMC's, thereby heating the entire board soldering. Small dots or squares of solder cream are placed over more uniformly than any other reflow soldering method. After each SMC pad, the SMC's are placed on the board, and the entire the solder melts, the board is removed from the vapor. Mean- board is heated until the solder melts. No adhesive is required while, the condensed vapor is collected, cleaned, and recycled since the SMC's are held in place by the sticky paste or cream. or, in simple systems, falls back into the reservoir of boiling The cream can be applied to the SMC pads with a handheld fluorinated liquid. wire, a squeeze applicator, a manual syringe, a pneumatic syr- Vapor -phase soldering provides highly uniform heating of inge that dispenses a preset quantity of cream, or by stenciling or SMC's. Also, the temperature of the condensed vapor remains screening. And solder cream can be applied by means of a pin constant so there is no danger of overheating a component array using the same principle sometimes used to simultaneously designed to accept vapor -phase temperatures (typically 215-250 deposit adhesive at each SMC location on a board. degrees Celsius). An advantage to using solder cream is that the placement of On the down side, the near instantaneous heating produced by the SMC's is less critical. When the solder melts, its surface the vapor -phase process can cause some SMC's to fail. For tension tends to pull slightly misplaced SMC's back into position example, ceramic chip capacitors should be heated at a max- precisely over the solder pads. Even boards having SMC's on imum rate of from 2 to 6 degrees per second; otherwise, the both sides can be reflow soldered without adhesive. First, the ceramic might develop microcracks that can lead to degradation SMC's on the top side of the board are reflow soldered. The and eventual failure. Without preheating, a vapor -phase system

69 properly -soldered SOT -23 transistor. Note the smooth, uniform appearance of the solder fillets at each terminal. Figure 8 is a close-up of a soldered diode and chip capacitor. Some components are especially difficult to inspect. For example, quad PLCC's (IC's having J -profile pins along each of four sides) can trap solder balls and conceal cold solder joints. Completed SMT boards can be tested by hand or with automated test equipment. A single- or double -sided "bed of nails" test fixture can be used to isolate defective SMC's and cold solder joints. While that permits quick identification of problems, building the test fixture is time consuming. Whether testing is done by hand or automatically, test probes should be touched to SMC solder pads or their conductive traces and not the terminals of the SMC. Properly designed SMT boards incorporate test point locations, such as those shown in Fig. 9. Replacing defective SMC's requires more patience and care than replacing through -hole components because SMC's are considerably smaller and have a much higher placement density. A soldering iron fitted with the same kind of tip used to hand- solder an SMC to a circuit board can be used to simultaneously FIG. 11-The SMT 2000 TRAINING KIT includes SMC's. conductive ad- heat the terminals of the same device in preparation for removal. hesive. solder. solder paste. 'weezers and practice boards. Figure 10, for example, shows how a Pak-X-Trac desoldering scissors is used to simultaneously heat the terminals on all four can take a chip capacitor from room temperature to 215 degrees sides of a quad PLCC. Hot air and vacuum desoldering tools can in less than a second. There is also some question about the also be used. integrity of vapor -phase solder joints. When desoldering, extra care must be taken to prevent over- Laser reflow soldering(Fig. 6-d) is among the most gentle heating of the board and adjacent SMC's. Also, it's important to soldering method. A pulsed laser beam heats each SMC terminal use non -vacuum hot-air desoldering tools with care since they in sequence. Laser heating results in considerably less heat stress might blow away the chip being removed and spray molten solder than other solder-reflow methods. However, it is slow and the across the circuit board. When the solder melts, the SMC should laser controller requires extensive programming. be twisted before it is lifted from the board to break the solder's surface tension; otherwise, the solder pad might lift away from Conductive Adhesive Bonding the board. Electrically -conductive adhesives have long been used to bond The procedure is unnecessary if the solder isslurpedaway by a the terminals of components to the conductive traces of hybrid vacuum desoldering tool. Removal of SMC's that have been microcircuits. They are relatively easy to use and they eliminate cemented to the board is more difficult since it is necessary to the thermal shock of soldering. Several families of conductive twist the device in order to break the adhesive bond after the adhesives are available, all of which consist of a conductive solder has been vacuumed away. powder suspended in a I- or 2 -part base. The most common Installing a new SMC isn't difficult. Indeed, it's sometimes conductive powders, in order of increasing resistance, include possible to simply place the SMC in position and heat its termi- gold, silver, copper, nickel, carbon, and graphite. Adhesive nals with an iron or a hot air tool until the solder remaining on the bases include urethane, acrylic, polyester, and I- and 2 -part pad reflows around the terminals. For best results, however, the epoxies. old solder should be removed with desoldering wick or a deso- Conductive adhesives can be applied by hand using a squeeza- ldering tool. The pads should then be retinned and fluxed, or ble dispenser, an automatically metered syringe, or a piece of coated with solder cream. Finally, the new SMC is placed over wire. They can also be applied by screening, or by an x -y pick- the pads and its terminals reflow-soldered to the board. and -place machine using the same kind of equipment that dispenses dots of non-conductive adhesive on circuit boards. Going further Thermoplastic conductive adhesives can be reworked using Only the highlights of surface mount technology can be cov- heat from an ordinary soldering iron or a hot air gun; the SMC ered in this special section. However, you can learn more and you can be removed after the adhesive softens. A new SMC can then can gain valuable firsthand experience by assembling the various be bonded to the same location by reheating the adhesive. SMT projects in this issue. A significant drawback of conductive adhesives is their rela- For an even broader hands-on introduction to SMT, consider tively high cost, especially for gold- and silver -filled material. the Vector Electronic Company's (12460 Gladstone Avenue, Since the conductive particles tend to settle out during shipment Sylmar, CA 91342)SM2000 Training Kit,shown in Fig. 1 I. The and storage, conductive adhesives must be carefully stirred or kit includes solder, solder paste, conductive adhesive, pre - shaken before use. Most conductive adhesives, like solder pastes etched boards, tweezers, desoldering wick, some SOT -23 di- and creams, have a limited shelf life of typically 6 to 12 months. odes and transistors, and hundreds of assorted chip capacitors Finally, some conductive adhesives may tend to give off haz- and resistors. The kit sells for $279.95. Items included in the kit ardous vapors. can be purchased separately. Manufacturers of surface mount components, equipment, and Inspection, testing, and repair supplies publish brochures, technical reports and specification Because of the very small size of the components, a just - sheets that provide excellent background information about completed SMT board requires a more careful inspection than a SMT. Electronics trade magazines often carry both news and conventional, through -hole board. In particular, look for solder technical articles about various aspects of SMT. For those who balls, solder bridges, improperly -soldered joints, missed solder need up-to-the-minute news about surfce-mount technology, connections, and for SMC's that have moved out of position or contact the Surface Mount Technology Association (Box 1811, "tombstoned" during soldering. Figure 7 is a close-up of a Los Gatos, CA 95031). R -E Once you master the Hand -Soldering SMC's techniques, soldering SMC's FORREST M. MIMS. III is easy, and fast

THE EASIEST WAY TO HAND -SOLDER SMC'S TO A CIRCUIT sticky dabs of solder paste or cream that are placed over each board is to use soldering tools and materials, such as solder- footprint before the SMC's are placed on the board. Reflow ing tweezers and hot-air soldering/desoldering systems, soldering can also be used by hobbyists. which are designed specifically for that task. Unfortunately, Let's now examine some hand- and reflow-soldering tech- specialized SMC soldering tools can be expensive and diffi- niques. cult to locate. However, it is safe to assume that such items will become more economical and widely available in com- Conventional soldering ing years. In the meantime, SMC's can be installed using It's surprisingly easy to solder or "tack" SMC's in place only the common tools shown in Fig. 1. Those tools include using only a handheld iron and small -diameter wire solder. an ordinary soldering pencil and a soldering iron equipped Solder 25 mils (0.025 inch) in diameter works best, but 30- with a slotted tips designed for SMC's. mil solder, which is more readily available, can also be used. There are two chief differences between hand -soldering The only special requirement is that the SMC must be held in conventional through -hole components and SMC's. First, place until at least one terminal or pin is soldered. SMC's are installed and soldered on the foil side of a circuit It's possible to use various kinds of adhesives to cement an board. Second, the absence of wire leads and pins inserted SMC in place for hand soldering. That, however, can un- through holes means that the SMC's must be secured in place necessarily complicate what is essentially a very simple during soldering. procedure. The adhesive must not be allowed to flow over the In industry, small droplets of adhesive are used to secure SMC's footprints, must be non -corrosive, and must be al- SMC's in place for wave soldering. While wave soldering lowed to set before the SMC's can be soldered. For those may be impractical for hobbyist applications, the same tech- reasons, we have experimented with two simpler and faster nique for securing SMC's in place is used when hand -solder- methods. ing circuits. For reflow soldering. SMC's are held in place by One method is to secure one side or corner of an SMC in

71 second or so. lightly touch the end of a length of solder to the junction and immediately remove both the iron and the solder. A shiny solder fillet should neatly bond the terminal to the footprint. Until you gain some hands-on SMC soldering experience. aln'ays inspect the completed junction with a magnifying lens before moving to the next terminal or SMC. If you use too much solder or form a solder bridge, use desoldering braid to carefully -remove the excess solder. Place an unused section of desoldering braid over a footprint and press it in place with a soldering iron tip. Within a second or so, capillary action will wick the excess solder on the lbotprint into the braid. Remove the iron and braid and go on to the next footprint as needed. Be sure to use a fresh section of braid at each footprint. Clip

101111"o off used sections of braid as necessary. If necessary, reapply a small amount of solder.

FIG.1-SMC's CAN BE HAND SOLDEREDusing only the common tools and materials shown here. Reflow soldering The most straightforward approach to mounting SMC's is place with masking tape as shown in Fig. 2. An exposed reflow soldering. The SMC is held in place with tweezers terminal or corner pin can then be soldered. The tape is then while a soldering iron presses one end terminal or corner pin removed and the remaining terminals or pins can be soldered. against a pretinned footprint. The tinned layer then melts and Another method is to place a tiny bead of reusable adhesive reflows around the terminal or pin and the footprint. Since no between the terminals on the bottom side of the SMC. Suit- additional solder is used, the tinned layer must include able reusable adhesives includePlasti-Tak, Fun-Tak.and enough solder to provide a good joint. Stikki-Wax. Those and similar adhesives are widely available at department stores. Use a toothpick, a sharply pointed probe, or pointed tweezers to apply the adhesive. Then grasp the SMC with pointed tweezers, place it on its footprints, and press it in place. It is important that the SMC be pressed flat against the board. Too much adhesive will keep the SMC suspended

slightly above the board and may even cause adhesive to creep between a terminal and its footprint. a

After an SMC is attached to the board with tape, cement, R or reusable adhesive, carefully touch the tip of a soldering pencil to the junction of a terminal and its footprint. After a iinumeamias emmiammono efoisissiellilliniall101.1411111111 1.1103

FIG.3-SOLDER PASTE OR CREAMis available in a syringe. That makes dispensing the pasta or cream convenient, once you get the hangofhow it's done!

Reflow soldering works best with SMC soldering tools that simultaneously heat all the pins or terminals of the chip being soldered. When a standard soldering iron is used, only one pin or terminal at a time can be heated. That can lead to problems when working with chip SMC's. If the tinned layer is too thick, only the terminal being reflow soldered will he pushed through the molten solder against the footprint; the remaining terminal will remain atop the tinned layer over its footprint. Also, the SMC will he badly tilted when the second terminal is soldered. On the other hand, if the tinned layer is too thin, there will be insufficient solder to form the bond. Therefore, consider other soldering techniques when working with chip components. Reflow soldering with solder paste or cream is particularly interesting since all the SMC's are soldered in place in a single operation without a soldering iron. Instead, the entire board is heated in a convection oven or on a hot plate. Unfortunately, solder pastes and creams are not always readily available, have a limited shelf life, and have instructions that must be strictly followed. Nevertheless, the method is so

FIG.2-ONE SIMPLE METHOD ofsecuring anSMCin place is to tape down efficient that it warrants discussion here. one side with masking tape. continued onpage 87

72 SMT PROJECT: Use surface -mountable LED FLASHER components to build this FORREST M. MIMS, III subminiature LED flasher. A GOOD WAY TO APPRECIATE THE MINIATURIZATION POTEN- How it works tial of Surface -Mountable Components (SMC's) is to assem- Figure 1 is the circuit for the flasher. In operation, the 555 is ble the subminiature LED flasher described in this article. connected as an astable multivibrator whose frequency of Besides teaching you the basics of how to assemble a simple oscillation is given by 1.44/(R1 + 2R2)Cl. With the values circuit using SMC's, the flasher has many practical uses. It shown in Fig. 1, LEDI will flash once each second. The rate can, for example, function as a warning flasher, indicator, a can be speeded up by reducing the value of RI or CI. Resistor tracking beacon for night -launched model rockets or in a R3 is a current limiter. number of other applications. For best results, the LED should be an AIGaAs super- A flasher made with conventional through -hole compo- bright unit. At night the flashes from such an LED can be nents can be assembled on a circuit board of about the same clearly seen from more than several hundred feet away. Keep size. But while the conventional circuit is more than 0.4 -inch in mind that the light level from the LED is directly propor- thick, the surface -mount version is less than 0.1 -inch thin. tional to the supply voltage. Although Fig. 1 specifies a 9 -volt That means that the surface -mountable circuit can be easily supply, the circuit can be powered by from 3 to 12 volts. slipped inside a slim slot or a space that might never be used Figure 2 shows the relative power output of the LED over that or be usable otherwise. range of supply voltages.

73 9V PARTS LIST R1-10 megohms, chip resistor, 1206 size SMC R2-100,000 ohms, chip resistor, 1206 size SMC RI R3 R3-22 ohms, chip resistor, 1206 size SMC 10MEG 22E2 C1-0.1 p.F, ceramic chip capacitor, 1206 size SMC

IC1-555 timer, SO -8 package LED1 LED1-super-bright red LED, see text Miscellaneous:PC board, 9 -volt battery clip, 30 -mil solder, reusa- R2 0.1 ble adhesive, etc. 100K -4? 555 An etched circuit board, super -bright LED, and all SMC's are available for $10.00, including postage and handling, from

Gilbert Electronics, P.O. Box 95, Leesville, TX 78122. Texas residents please add appropriate sales tax. c, ,

TO 9V LI ATTERY

FIG. 1-WHEN THIS LED FLASHER is assembled using SMC's, the assembly is about 0.1 -inch thick. LEDI 6 -

_._. 4

Lu R3 IC1 Lu

3 - FIG. 4-THE COMPLETED CIRCUIT BOARD. The light from the super - bright LED can be seen for several hundred feet.

J2 The circuit can be assembled in less time than an equivalent conventional circuit since no holes need be drilled in the circuit board. Although an experienced technician can install the components with a 30 -watt soldering iron having a wedge tip, for best results use a I5 -watt pencil iron having a pointed

or conical tip.

Begin assembly by tinning the component footprints on

0 1 2 3 4 5 6 7 8 10 11 12 the hoard. First, use an abrasive cleanser or steel wool to SUPPLY VOLTAGE VOLTS polish the copper traces. Wash and dry the board. Then use FIG. 2-RELATIVE OUTPUT of a super -bright LED is a function of its masking tape to attach a corner of the board to a flat, movable supply voltage. surface placed on your workbench. Tinning the board takes just a few minutes. Just touch the soldering iron tip to a footprint for a second or so and then touch the end of a length of 30 -mil rosin -core solder to the r fbotprint. When the solder flows over the footprint, imme- Cl diately remove the iron and solder and proceed to the next footprint. Be sure to rotate the board for best access to each LED1 footprint. IC1 After the footprints on the board are tinned, remove any INCI-1 yl excess solder from the footprints with desoldering braid. That procedure will also remove any solder bridges. b FIG. 3-USE THE PC PATTERN shown in a to etch the board. The parts After the hoard is tinned and the excess solder is removed, layout is shown in b. remove any solder halls or splashes from the traces and the substrate. Then use a defluxing agent to remove the flux Preparing the board residue from the hoard. The circuit should he assembled on a thin PC hoard. A pre - etched hoard and all necessary components are available from Installing the SMC's the source given in the Parts List. You can also make your Begin assemhly of the LED flasher by first attaching the own hoard using the pattern shown in Fig. 3-a. However or 555 to the hoard. Use the methods described in the article on wherever you obtain your hoard, the component layout is SMC soldering, which can he fOund elsewhere in this sec - shown in Fig. 3-h. continued an page 88

74 SMT PROJECT: Here's a simple "dark meter" that you can METER build using SMCs. FORREST M. MIMS, Ill

IN THIS ARTICLE WE WILL SHOW YOU A SIMPLE LIGHT METER feedback resistor. That provides a two -state (off -on) output volt- with a built-in four -element LED bargraph readout that com- age instead of the linear output that characterizes an op -amp bines the advantages of analog and digital displays. Since the operated with a feedback resistor. number of illuminated elements in the bargraph increases as A voltage input is applied to the inverting input of the op -amp. the light reaching a phototransistor decreases, the circuit can When that input exceeds the reference voltage, the output of the be considered a "dark meter." A bonus feature of the circuit op -amp is low; as far as the LED is concerned, the output is is that it can also be used as a four -step timer or as a simple ground. Therefore, the LED switches on. Series resistor RI resistance indicator. limits current to the LED, thereby protecting both the LED and The circuit shown in Fig.I can be assembled on a tiny the output -driver stage of the op -amp. When the input voltage is below the reference voltage, the output from the op -amp swings circuit board having an area of only about 1.25 square inches, to near the supply voltage toutput high). The output LED, which a size made possible by the use of surface -mountable compo- no longer receives sufficient forward bias, then switches off. nents. Consequently. the circuit is much more compact than The circuit is called a "comparator" since it compares the an equivalent circuit assembled from conventional through - voltages at its two inputs and switches on when one exceeds the hole components. other. The circuit shown in Fig. 2 can be changed from an Though the circuit is configured as an inverse light meter inverting comparator to a non -inverting comparator simply by or "dark meter," it can be revised so that the number of switching the connections to the inputs. Then the output will glowing elements increases with the light level. It can also be swing from low to high when the input voltage exceeds the used as a timer or resistance indicator by omitting phototran- reference voltage. sistor QI. Even if none of the applications for the circuit are Referring back to Fig.I. ICI is a quad comparator in a 14 -pin of interest, you might want to assemble it anyway since it SO package. Resistors RI through R5 form a 4 -stage voltage divider with taps connected to the non -inverting inputs of each provides an excellent hands-on introduction to surface -mount comparator. The reference voltage delivered to each comparator technology. is determined by the setting of trimmer RI. Each comparator in Fig.I functions exactly like the model How it works comparator in Fig. 2. Therefore, the outputs from the com- There is nothing new about the design of the circuit in Fig. I, parators will swing, in sequence, from high to low as the input which is often called a parallel or "flash" analog -to -digital voltage rises above the reference voltage applied to each com- converter. To understand how the circuit works, it's necessary to parator. The output LED's will then switch on in sequence as the review the operation of the basic inverting comparator shown in voltage rises. Fig. 2. In that circuit, a reference voltage is applied to the non - When the circuit is configured as a light meter, the inverting inverting input of an operational amplifier operated without a inputs of the comparators are connected in common to the

75 PARTS LIST W. All resistors are 1206 size SMC's unless noted R10 R1-100,000 ohms, trimmer potentiometer, Micro -Ohm RV43B- LED1 330 GREEN CV or equivalent R2 -R5--1000 ohms R6 -R10-330 ohms Bt Semiconductors RI 3V IC1-LM339 quad comparator, SO -14 package 100K LED1-Green LED, SOT -23 package, ROHM SLM-13M or LED5 equivalent 2 SOvS. LED2-LED5--Red LED, SOT -23 package, ROHM SLM-13V or R5 equivalent ICI -a RED R2 it 330 St Q1-0P593C NPN phototransistor (TRW), or equivalent 1/4 1K LM339 Other components B1-CR2320 or similar 3 -volt lithium coin cell

LED4 Miscellaneous: Lithium coin cell holder (Keystone P/N 107), PC board. Reusable adhesive or masking tape. 25 or 30 mil solder 4VS/04.- A complete kit including a drilled, etched, and plated PC

IC1 -b .0, RED board, 01, all SMC's, battery, battery holder and solder is 133 330 S2 1/4 available from the Heath Company, Benton Harbor. MI IK LM339 49022 for $19.95 plus postage and handling; for credit-card orders, call 800-253-0570. Michigan residents must add ap- LED3 propriate sales tax. Specify catalog number SMD-1. 14

R8 IC1-c 'A' RED R4 330E2 swings from high to low and LEDI switches on. Additional 1/4 1K LM339 LED's switch on in sequence as the light level continues to fall. Incidentally, note that the common inverting inputs appear to 11 LED2 be floating when QI is fully switched off (dark). Actually, a few AVY* tenths of a volt appear between those inputs when QI is dark. The R5 10 R9 1K RED inputs can be connected to the positive supply through a pull-up 330 SI resistor, but leaving them "floating" makes the applications discussed at the end of this article possible.

Preparing the circuit board Figure 3-a shows a suggested layout for the circuit board: the (.1(:), 01 0P593C hoard itself is shown in Fig. 3-b. Also, an etched, silk-screened,

RIO FIG. 1-USING SURFACE -MOUNT COMPONENTS this bargraph "dark OLED1 meter" can be assembled on a circuit board with an area of just 1.25 inches. R9 00 LED2 R2 R8 OLED3 :L +V 0 R4 R7 0 LED4 R3 R6 0 LED5 B1 FIG. 3-USE THIS LAYOUT a when building the circuit. The PC board is INPUT shown in b.

and pre -tinned board is available as part of a kit that includes all REFERENCE necessary components: see the Parts List for more information. Note that the hoard in the kit also includes a solder -mask coating that both simplifies soldering and greatly reduces solder -bridge problems. The board also includes drilled mounting holes for a Keystone 107, or equivalent, lithium coin -cell holder. If you build your own board, follow the tinning procedure given in the LED -flasher project described elsewhere in this FIG. 2-IN AN INVERTING COMPARATOR. the output is low when the input voltage exceeds the reference voltage: the output is high when the input is special section. Also review the SMC soldering procedures lower than the reference voltage. given elsewhere in this special section before soldering SMC's to the circuit board. collector of phototransistor QI . When QI is illuminated, its Begin construction by installing the LM339. Be sure to solder collector -emitter junction conducts, thereby placing all the inver- a corner pin first. If the device stays aligned over the remaining ting inputs within a few millivolts of ground. For most settings of pads, then continue soldering. RI. each of the four reference voltages exceeds that value. Next, install the chip resistors one at a time. If you use the tape Therefore, when QI is illuminated, the output from each com- method to hold the chip resistors in place. you can solder one parator is high and its respective indicator LED is off. As the terminal of each resistor: then you solder the remaining termi- light level at QI is gradually decreased, the voltage at the invert- nals. You can use the same approach when installing the LED's. ing inputs rises until it exceeds the first comparator's reference No matter which method you use, until you become an experi- voltage (pin 10). The output from that comparator (pin 13) then contimwd on page 88

76 Use surface -mount SMT PROJECT: technology to build an I -R REMOTE ON A infrared transmitter small enough to fit on your KEYCHAIN keychain. FORREST M. MIMS, Ill ONE OF THE MAJOR CAPABILITIES OF SURFACE -MOUNT TECH- Q2 off The LED is then switched off. The charge/discharge nology is that experimenters and prototypers can assemble cycle is then repeated at a frequency that is determined by ultraminiature, fully functioning circuits only a few milli- Cl's value. The circuit drives the LED with 725 pulses per meters thin. For example. you can make an optoelectronic second using the values given in the Parts List. remote -control transmitter thatis so small thatit can he slipped inside a plastic identification -tag holder, yet it's Preparing the circuit board powerful enough to activate a receiver located more than 10 An ultra -thin circuit Nrard is required if the project is to fit feet away. inside the thin label space of a plastic 1D -tag holder. A The transmitter, shown in Fig.I. projects a pulse -modulated red or near -infrared beam. Although a 555 timer is often used as an LED driver in this kind of application, the simple CI two -transistor driver shown is a better choice because it can 01uF drive an LED with greater current. Moreover,it can he powered by a supply of less than one volt. 81 r. 3V RI LEDI How it works 22K Referring to Fig. I. assume that QI and Q2 are initially off when power switch SI is closed. Capacitor CI then begins 01 charging through resistors RI and R2, and LEDI. Eventually 2N2907 Q2 2N2222 the charge on CI becomes high enough to switch QI on, Si O which then switches Q2 on. R2 When Q2 is on, LEDI is connected directly across battery 1ME3 RI through Q2's emitter -collector junction. Meanwhile, CI discharges to ground through Q1's base -emitter junction. Eventually the charge on CI falls below that necessary to keep Fig. 1-THE KEY -CHAIN TRANSMITTER uses two transistors to generate a QI on. Transistor QI then switches off and. in turn. switches red or near -infrared beam that pulsates at approximately 725 Hz.

77 trltM PARTS LIST-TRANSMITTER IIII R1-22,000 ohms, SMT size 1206 1.0" R2-1 Megohm, SMT size 1206 SMT size 1206 1/4" C1-0.1 HOLE Q1 -2N2907, PNP transistor, SOT -23 package Q2 -2N2222, NPN transistor, SOT -23 package LED1-Light-emitting diode, near -infrared or super -bright red B1 -3 -volt lithium coin cell, type 2016 2.0" Miscellaneous: circuit -board material, plastic keychain ID - tag holder, solder, masking tape, wire, etc. FIG. 2-USE THIS TEMPLATE as a general guide when making the printed - circuit board.

Q2 QI U-43 I R2 Therefore, after all the footprints are coated, use desoldering I RI braid to remove excess solder and solder bridges. Cl LED SOCKET Installing the SMC's The SMC's can be attached to the board with either conductive adhesive or solder. Both methods are described in detail elsewhere in this special section. If you use solder, the Fig. 3-THE COMPONENT LAYOUT is somewhat unusual because the LED's socket is made from thin tubing, while the battery is secured by four method of temporarily securing the SMC's in place with tape bumps of solder. works best. Attach the SMC being soldered to the board with a bit of masking tape across one of its ends and solder the double -sided copper -clad board only 7 -mils thick that is ideal exposed terminal or pins with a small amount of solder. If for the project is available from the Edmund Scientific Co. necessary, make sure the SMC is flat against the board by (101 E. Gloucester Pike. Barrington, NJ 08007). A 12 x 18 pressing it down with a pencil eraser while the solder is still inch sheet of the board, catalog number E35,652, sells for molten. Then remove the tape and solder the remaining only $2.50. terminal or pins. Although the transmitter is assembled on only one side of After the SMC's are soldered in place, prepare a socket for the board, keep in mind that SMC's can be mounted on both the LED by cutting two 0.5- to 0.65 -inch lengths of 62.5 mil sides of a double -sided circuit board. The foil pattern for the Vu, inch) O.D. brass tubing purchased from a hobby shop. board is shown in Fig. 2; use it as a general guide and apply Prepare the tubes for soldering by burnishing them with steel the resist by hand using a small brush, which is a somewhat wool or fine sandpaper. Insert the wire from a bent paper clip faster way to make a small board compared to using the in one end of one tube and melt a line of solder along its entire photo -resist technique. length. Repeat the procedure for the second tube. Then use the paper clip to hold one of the tubes in place over its Hand -made board footprint and remelt the solder on both the tube and the Use a pair of scissors to cut the board to size, then polish footprint until the tube is bonded in place. If necessary, apply the tbil with fine steel wool. Use a 1/4 -inch hole punch to some additional solder to the side of the tube away from the create the hole for the keychain, then place the various second tube's location. Repeat the procedure for the second components including BI, a 2016 lithium coin cell, on the tube. Be sure to keep solder from entering the open ends of hoard in the approximate locations shown in Fig. 3. Mark their terminal or pin locations on the board with a pencil. Then remove the parts and pencil in the required terminal footprints and interconnection traces. Be sure to include four marks around the perimeter of the lithium cell. Later, solder bumps will be placed on the marks to keep the coin cell in its proper place. Finally, use a sharp -pointed resist pen to trace over the penciled traces and footprints. Use a straightedge for best results and be careful to avoid smearing the ink. After the resist dries, cover the back side of the board with a protective layer of tape. Then immerse the boardin an etchant solution. Etching time can be speeded up by agitating the solution. After the board is etched, thoroughly rinse the hoard under running water. Unless you plan to attach the SMC's to their footprints with conductive adhesive, the footprints of the etched board should be plated with a thin layer of solder or tin. A dip -and - dunk tin-plating solution is available from The DATAK Cor- Fig. 4-THIS CLOSE-UP SHOWS how really small the components are. The poration (Guttenberg. NJ 07093). Alternatively, you can melt transistor, labeled U8, is actually smaller than the resistor and capacitor a thin layer of standard rosin -core solder overeach footprint. chips. The two "giant" horizontal tubes near the bottom are the LED For best results, the solder layer should be thin and flat. socket. Surface -Mount

C2 100pF R1 100K

C3 O 1N914D1 047 Cl ICI 01 LM308 RY1

IC2 R4 567 50K rir© 9V (SEE TEXT) VN R3

100K C4 C5 C6 R2 i 3 3p.F 1.5µ_F 1K 6V 6V

Fig. 5-IF YOU NEED A RED-LIGHT RECEIVER, try building this circuit. Most of what's needed is probably lying somewhere around your shop. Relay RY1 can be any low -current relay rated from 5 to 9 - volts DC; such relay's are called "sensitive relays."

the tube, especially the end closest to the edge of the circuit small screwdriver or a flat implement passed through the slot. board. Fig. 4 shows the tubes, and the QI/Q2 circuit soldered Adjusting the squeeze switch can be tricky. If the LED stays to the board. on when the board is slipped inside the tag holder, bend the Switch SI is a squeeze switch made from an L-shaped piece exposed copper end of the L slightly upward. If excessive of circuit board, as shown in Fig. 3. The exact shape of the pressure is required to close the switch, expose additional switch is unimportant so long as it fits the allowed space. copper by removing a narrow strip of the tape with a knife. Solder a short length of wire -wrap wire to the lower side of the base of the L. With the exception of a narrow strip of Suitable remote -control receivers exposed copper along the end of the lower side of the L (the The keychain transmitter can be used to trigger various dashed line in Fig. 3), cover both sides of the L with a clear kinds of optoelectronic receivers. The circuit for a suitable tape. Solder the exposed end of the wrapping wire to the receiver is shown in Fig. 5. The circuit uses a 567 tone adjacent positive circuit -board foil. Then attach the copper L decoder to help prevent triggering by any unauthorized trans- to the hoard with a hinge made from a strip of clear tape. mitters. In operation, pulsed infrared or visible light is received by Testing the circuit QI and transformed into a pulsed voltage. Any NPN pho- Test the circuit before installing itin an ID -tag holder. totransistor can be used for Ql. The signal from QI is ampli- First, insert the leads of a red AlGaAs super -bright LED into fied 1,000 times by ICI, an LM308 high -input impedance the LED socket (be sure to observe polarity). Then place BI operational amplifier, and is passed to IC2, a 567 tone de- on the board (positive side down) and press the squeeze coder. Resistor R4 and capacitor C4 determine IC3's center switch. The LED should glow. When the LED is pointed frequency. Resistor R4 is a potentiometer rather that a fixed toward a phototransistor or solar cell connected to the input of resistor to permit the receiver to be tuned. IC3's output drives an audio amplifier, a 725 -Hz tone should be heard from the RYI, a low- current relay. amplifier's speaker. The receiver can be assembled on a printed -circuit board If the circuit is working properly, remove the LED and slip using either conventional or surface -mountable components. the circuit inside the ID -tag holder. You might want to first Both ICI and IC2 are available in small outline packages. place a self-adhesive label on the back side of the board. You Test the receiver by pointing the transmitter at QI while can leave the label blank or record the circuit's operating carefully adjusting the receiver's R4. With R4's wiper set parameters on it. At least two kinds of plastic keychain ID -tag near its midpoint, the relay should pull in when QI is receiv- holders are available from office supply companies. The one ing the transmitter's signal. For best results, bright ambient used for this project, which has a retail cost of approximately light must not be allowed to strike QI: otherwise, QI may 70 cents, has a 2 -mm high slot at one end, opposite the hole become saturated and fail to respond fully, or at all, to for the keychain. incoming pulses from the transmitter. If ambient light proves After the circuit is inside the holder, insert the LED into its to be a problem, place one or two pieces of developed color holder through the 2 -mm slot. The slot also simplifies re- film in front of QI to serve as a near -infrared filter, and insert a moval of the circuit board: Simply push the board out with a near -infrared LED into the transmitter. R -E

79 Your Best Source for SMD Test Accessories is POMONA ELECTRONICS

PATCH CORD; SMD GRABBER SMD TEST TWEEZER TO BNC DO-IT-YOURSELF SMD BOTH ENDS: MODEL 5301 MALE: MODEL 5142 (SHOWN). GRABBER ": MODEL 5243 TO TWO SINGLE STACKING BANANA PLUGS: MODEL 5143

SMC MICROT PTEST FREE 1987 GENERAL CATALOG PLCC TEST ADAPTORS PROBE TO SINGLE FIVE MODELS: 20 PIN, 28 PIN, STACKING BANANA 44 PIN, 52 PIN, 68 PIN PLUG: MODEL 5144 PONION VIII'( IRO\ ('1 FBI V 1...ssoRiis 087

ITTPomona Electronics 1500 E. Ninth St., ?omona, CA 91766 Tel: (714) 623-3463

CABLE ASSEMBLY; SMD SOIC CLIPTEST CLIP: MODEL MOLDED BREAKOUT; SMD GRABBER ' TEST CLIPS TO 5250 (8 PIN); 5251 (14 DIN): 5252 GRABBER TEST CLIPS TO BNC MALE: MODEL 5304 (16 PIN) SHOWN: 5253 (20 PIN): FEMALE BNC: MODEL 5305 5254 (24 PIN)

*71

80 Our Products are available through ycur favorite electronics parts aistriputor. CIRCLE 101 ON FREE INFORMATION CARD Who needs copper foil and solder when you can use these conductive inks and adhesives? Conductive Inks and Adhesives FORREST M. MIMS, III FOR MANY YEARS, THE HYBRID MICROELECTRONICS INDUS - resemble paints. Indeed, conductive paints and coatings are try has used electrically -conductive inks and adhesives to available that will add RF shielding to enclosures. interconnect components, and to bond them both mechan- Conductive inks are often used to repair broken traces and ically and electrically to a substrate. Those same inks and to form new traces on etched circuit boards. For decades, adhesives can also be used with all sorts of surface -mounta- however, their chief application has been to form conductive ble components. traces on hybrid microelectronics substrates. Generally, a While conductive inks and adhesives are usually used with conductive -ink pattern is screen or stencil printed on a ce- standard circuit boards or ceramic substrates, they also make ramic substrate that is then fired in an oven. The result is a possible some very unusual and even novel circuit -assembly very tough and permanent conductive network. Additional methods. For example, they permit surface -mountable com- conductive layers can be added if previously -applied con- ponents and even complete circuits to be installed on paper, ductive layers are first coated with a dielectric paste. plastic, glass, wood, painted surfaces, and many other sub- Figure 2 shows a very simple hybrid microcircuit, a micro - strates. Do-it-yourself examples of such circuits are pre- switch Hall -effect sensor assembled on a thin ceramic sub- sented elsewhere in this special section. strate. The Hall sensor is installed behind the oval protrusion. Figure I shows an assortment of conductive inks and ad- The three shaded rectangles are thick -film resistors that have hesives. Whether or not you decide to experiment with con- been screened onto the substrate. Upon close examination, ductive inks and adhesives now, chances are you will two of them show the thin slice marks that result from laser encounter those versatile counterparts of copper foil and trimming, a method used for tuning a low -tolerance thick - solder sometime in the future. Therefore, let's take a close film resistor to a precise value. The Hall sensor, the resistors, look at both conductive inks and adhesives. and the three terminals are interconnected by a solderable conductive ink that has been screened onto the substrate and Conductive inks then fired. Electrically conductive liquids and pastes that can be ap- The conductive property of an ink is provided by powdered plied to a substrate to form a network of interconnections are gold, silver, and other metals. Gold, while expensive. collectively known as conductive inks. Those materials are provides very low resistance and long-term stability. Silver is usually much more viscous than drawing ink, and often cheaper than gold but has several times its resistance. Further -

81 TABLE 1

Conductor Sheet Line Composition Resistivity Resistance (ohmsisquare cm) (1 0.02' ) Gold 0.003 0.15 ohm Silver 0.020 1.00 ohm Palladium Silver 0.035 1.75 ohms Platinum Gold 0.100 5.00 ohms

Source: "Designers Handbook on Thick Film Microcircuits," Paine Instruments, Inc.

unlimited shelf life.It would be non -corrosive, simple to apply, odorless, non-flammable, and non-toxic. It would be available in bulk for screen printing, and in a handheld pen for the instant preparation of SMC-prototype circuit boards and for the repair of conventional boards. Though many different kinds of conductive inks are available, none possess all of the properties of the ideal material we've outlined. Inks blended with powdered gold or silver provide the lowest resistance, but they are expensive. Copper - and nickel -filled inks are inexpensive, but their higher resistance can affect the operation of a circuit if not properly FIG. 1-CONDUCTIVE INKS AND ADHESIVES are available from a variety compensated for. of manufacturers. Another drawback to conductive inks is that shelf life is relatively short, usually ranging from six months to a year. Still another disadvantage is that some materials require special handling since they may be hazardous to health. And while some conductive inks will dry fairly rapidly in open air, others require that you select either heat or a considerably drying time. Applying inks In an industrial setting, conductive inks are usually applied by screening or stenciling. Those methods require considerable preparation time and often are impractical when only a few boards are needed. Fortunately there are several ways to apply conductive inks by hand to make relatively simple circuit boards. It's even possible to make multiple -layer boards by interspersing conductive layers with a layer of insulating material. Before going on, a few caveats are in order. The best 1 INCH conductive inks can be very expensive. Also, the physical properties of various inks, both when liquid and after harden- FIG. 2-THIS MINIATURE THICK -FILM hybrid microcircuit uses conductive ink for its interconnections. ing, can be very different. The metal particles in a conductive ink generally do not remain in suspension. Instead, they sink more, silver may migrate from the fired ink over time. Alloys to the bottom of their container under a layer of syrupy carrier of platinum and gold or silver are used when it is necessary to fluid. Therefore, for lowest resistance it is essential that the solder to the fired ink. Copper and nickel are used as inexpen- particles be thoroughly mixed with the carrier before the ink sive substitutes for gold and silver. Both, however, have is applied. Shaking alone may not be adequate; stirring may higher resistance and other less -desirable characteristics. be required. Finally, the carriers of most conductive inks are The resistance of conductive inks is often specified in terms volatile and may be flammable, hazardous to health, or both. of sheet resistivity. Sheet resisivity, which is given in terms of Therefore, it is essential to use conductive inks in a well ohms -per -square centemeter, is the electrical resistance ventilated area and to follow the safety instructions provided across opposite sides of a square pattern of conductive mate- with a specific product. rial. Resistance of conductive inks can also be given in terms The ideal way to apply conductive ink by hand would be of a line of material having specified dimensions. The resis- with a drawing pen. However, the author has been unable to tances of several common inks used in the hybrid -micro- find a pen intended for that application. It is possible to load electronics industry are shown in Table I. conventional drawing pens with conductive ink. But, the viscous nature of most conductive inks means that they must Ink properties first be thinned with a suitable solvent or carrier. The draw- The ideal conductive ink would be an inexpensive material back to that procedure, aside from it being rather messy, is having zero sheet resistivity, a short curing time, and an that thinning increases the resistance of the ink. Furthermore,

82 Surface -Mount Another method is to use a hand-held automat ic dispensing syringe to form lines consisting of precisely metered dots of material. The necessary equipment, however, is expensive. A conventional syringe with a hand -depressed plunger can be used but only after some experience has been gained to avoid dispensing too much material. It's best to experiment before selecting a method for hand applying a conductive ink. Then, before beginning work, ft% plan each step carefully. For best results, use a pencil to draw the outline of the circuit on the substrate.If you use a transparent substrate such as Mylar, you can draw the circuit outline on a sheet of white paper that is then placed under the substrate, allowing you to trace several circuits from a single pattern.

Using inks as adhesives The composition of some conductive inks and adhesives is very similar. And there are some inks that can provide a relatively strong bond to an SMC terminal or pin. Therefore, it follows that some conductive inks can double as conductive adhesives. FIG. 3-USING THE TRANSFER METHOD to apply conductive adhesive to The surface -mount circuit builder can exploit the adhesive the pins of an SO device. property of some conductive inks to speed up the assembly of simple prototypes. For example, the author has assembled a number of miniature circuits using only a lacquer -based conductive ink. First, the footprints for a component are formed with the material. The SMC is then placed on the footprint. Additional component footprints are made and their SMC's are positioned in place. Interconnections between the footprints are made as the circuit is assembled. Any remaining interconnections are formed after all the SMC's are in place. Though the lacquer -based ink hasn't the strength of a conductive adhesive, circuits assembled in that fashion have survived being dropped on the floor from a distance of as 101 much as a few feet. NICKEL PRINT Conductive adhesives APOR RA101111 iP Heretotore, the principle application of adhesives in sur- WHIM OR MAI II SWALLOW0 face -mounting technology has been to use non-conductive 4:" ...AM, carman writI' CONTENTS: Z FL OZ. 010 materials to bond SMC's to a circuit board in preparation for wave soldering. Although considerable literature and many application notes on the use of non-conductive adhesives for that purpose have been published, comparatively few publications about surface -mount technology even discuss conductive adhesives. That is surprising, particularly since conductive adhesives provide a fast and reliable method of attaching SMC's to a circuit board without using solder. FIG. 4-THESE TWO CONDUCTIVE INKS are low priced, readily available, Moreover, conductive adhesives are well suited for use with and suitable for hand application. heat -sensitive components, and they can be used to make considerable experimentation may be needed to arrive at the quick circuit repairs and modifications when soldering best combination of pen -orifice size, ink, and thinner. equipment is either unavailable or impractical. A simpler method is to apply the ink dot-matrix style; that The ideal conductive adhesive would be an inexpensive, is, a droplet at a time, by means of a small wire dipped into single -part material having zero electrical resistance, a short the material. Generally, dipping the wire into the ink will curing time, and an infinite shelf life.It would be non- pick up enough fluid for several dots. The dots should be corrosive, simple to apply, provide a strong bond, and be placed close together so they form a continuous line. That is easily reworked. Finally, it would be odorless, non-flamma- best done by a quickly tapping the end of the wire against the ble, and non-toxic. substrate while moving itin the desired direction. With While the perfect conductive adhesive has yet to be formu- practice, you can form closely -spaced component footprints lated, a surprising number of products possess many of those and both curved and straight lines. While that low -tech meth- properties. Adhesives blended with powdered gold or silver od is both slow and tedious, it works quite well with simple provide the lowest resistance, but they are expensive. Copper - circuits. In fact, a complete interconnection pattern for a and nickel -filled adhesives provide reasonably low resistance circuit consisting of an IC and half a dozen outboard compo- for less cost. nents can be produced in 10 minutes or so. Some conductive adhesives have novel properties. For

83 instance, some can actually be soldered -to using con- It's possible to apply conductive adhesive to the footprints ventional tin -lead solder. And some conductive adhesives are using a syringe or similar applicator. However, that applica- thermoplastics that can be reworked merely by reheating the tion method requires some experience to avoid applying too existing adhesive. In other words, a connection can be heated much material. A toothpick or wire applicator gives the until the adhesive softens enough for the SMC to be removed. same -sized droplet each time. A replacement SMC can then be bonded in place with fresh An alternate way to hand -apply conductive adhesive is the adhesive or, with some materials, by heating the joint once transfer method. In that method, the adhesive is applied to again. the terminals or pins of an SMC instead of to its footprints on Unfortunately, the typical shelf -life of conductive ad- the circuit board. An advantage of the transfer method is hesives ranges from two months to a year, with six months speed, since all the terminals or pins on one side of an SMC being fairly typical. Another drawback is that some materials can be coated with material in a single operation. To use that require special handling since they may be hazardous to method, first place a few drops of material on a flat surface health. While those drawbacks are certainly undesirable, they such as a glass microscope slide or paper card taped securely are not unique to conductive adhesives. Indeed, most ad- to a work surface. Then grasp the SMC with tweezers and hesives, conductive or otherwise, have limited shelf lives and simply dip each terminal or pin into the material as shown in some require special handling. Hg. 3. With practice, all the pins on one side of a small outline IC can be dipped at once. The SMC is then placed Conductive -adhesive types over its footprints on the circuit board. Regardless of their conductive filler, conductive adhesives No matter which application method you use, always can be divided into several major classes. The two most remember that conductive adhesives, like many other ad- important are: hesives, may be flammable or hazardous to health. There- Thermosetting adhesives.-Those adhesives have proven fore, always work in a well -ventilated area and be sure to their reliability during many years of use in the electronics follow the safety precautions provided with the product. industry. Thermosetting adhesives provide a very strong, inflexible bond. They are cured by means of a chemical Conductive -ink and -adhesive manufacturers reaction that is initiated by a chemical catalyst, heat, or An acrylic -based, silver -filled ink that is easy to mix and to ultraviolet radiation. The resulting bond is permanent, and apply by hand is made by the Hysol Division of the Dexter cannot be reworked unless the adhesive is first shattered or Corporation. The product number is 140-18-Q. That material dissolved with a solvent. Examples of thermosetting ad- adheres well to paper, cardboard, wood, phenolic, poly- hesives include I- and 2 -part epoxies, acrylics, and also, the styrene, vinyl and butyrate. polyesters. Another silver -filled ink that is easy to mix and to apply is Thermoplastic adhesives.-Those adhesives do not under- C-225-3. That ink adheres well to paper, polyester go a chemical change when a bond is formed. Therefore, they film, phenolic, and ceramic. can be reworked simply by applying heat until the material Dynaloy, Inc. sells an evaluation kit containing four 50- softens enough to remove the bonded component. A second gram bottles of either epoxy -base or polyester -base silver - application of heat permits a replacement component to be filled conductive ink. Each 200 -gram kit costs $100. Those attached. Though thermoplastic adhesives provide a weaker inks are more viscous than the preceding ones and must be bond than thermosetting adhesives, the fact they can be stirred to mix the silver particles and the carrier. reworked makes them well -suited for many applications in Most inks can be cured by placing a freshly prepared which they will be subjected to only mild mechanical substrate under a desk lamp. For best results, however, be sure stresses. Examples of thermoplastic adhesives include nylon, to refer to the instructions supplied with the product. polyimide siloxane, and various proprietary materials. Very If you can't find the industrial -grade inks described above, flexible thermoplastic adhesives can be formulated by mixing don't despair. GC Electronics sells conductive inks for repair- synthetic or natural polymers (e.g. neoprene or rubber) in a ing etched circuit boards that are also suitable for bonding solvent or other suitable carrier. SMC's to a circuit board. Their highly conductive Silver Print (Cat. No. 22-201) is $21.62 for half a troy ounce (price Applying conductive adhesives subject to change with the price of silver). GC's Nickel Print In an industrial setting, dots of conductive adhesive are (Cat. No. 22-207), has a higher resistance than Silver Print, applied to each SMC footprint by screening, an array of pins, but the two -ounce bottle shown in Hg. 4 costs only $3.83. or an automatic syringe dispenser. The SMC's are then placed Both of those products can be ordered from GC Electronics or over the footprints and the adhesive or ink is allowed to cure purchased at many electronics dealers. or dry. If those GC products aren't readily available, you can There are several ways to apply conductive adhesives by obtain satisfactory results with a silver -filled conductive lac- hand. A hand-held automatic dispensing syringe will place a quer available from some automotive parts stores that sell precisely metered quantity of material over each footprint. NAPA parts. The product, which is dyed to resemble copper, The necessary equipment, however, is expensive. For- is Loctite Quick Grid Window -Defogger Repair Kit. The kit, tunately, there are some very simple alternatives. which sells for around $7.25, includes a small bottle con- The simplest method is to dip a toothpick or wire into the taining 0.05 fluid ounces of silver -filled lacquer. It is also adhesive to pick up a small droplet of material. The droplet is shown in Fig. 4. then touched to the desired footprint. If the material is slow Dynaloy, Inc. sells various one -part conductive -epoxy pas- drying, the conductive material can be applied to all the tes that are well -suited for conductive bonds. An evaluation footprints before the SMC's are installed. If the material is kit containing 50 grams each of one pure -silver and two fast drying, only the material required for an individual SMC silver -alloy adhesives costs $100. Conductive adhesives are should be applied. also available from Amicon. R -E 84 SMT PROJECT: A BUSINESS -CARD

TONE GENERATOR Who needs a PC board?

FORREST M. MIMS, Ill SURFACE MOUNT TECHNOLOGY OFFERS CIRCUIT BUILDERS section of clip -on cylindrical -radius contacts made by Tech - entirely new methods of assembling solid-state circuits. For Etch. Inc. (45 Aldrin Road. Plymouth. MA 02360). One example. the circuit shown in Fig.I can he installed without linger from a contact section is used for the battery clip. An solder on an ordinary paper business card. The prototype Di -linger section. which we'll call the switch strip, is used for version of the circuit was built in around 90 minutes. the keyboard. The primary value of this particular circuit -on -paper is that The circuit also requires conductive ink and adhesive - it vividly illustrates some of the unique capabilities provided by surface -mount technology. Among the more interesting techniques it will show you is how to torm resistors simply by 6V drawing them in place with a graphite pencil. r

How it works Sl-a S1 -b Reftrring to Fig.I.the circuit for the tone gererator consists of a 555 timer connected as an astable oscillator. The Al 2 circuit's frequency of oscillation is controlled by resistors RI-RI7 and Cl. The output from the 555 drives a piezoelectric -buzzer element. Note that Fig. Ispecifies a power supply voltage of 6. Keep in mind that selected 555's and low power 555's can he powered by 3 volts.

Circuit assembly Figure 2 shows both the conductor traces and the component layout tor the assembled circuit. For the circuit to tit on a 'SEE TEXT business card. two specialized components are required. The piezoelectric-butzer element is a miniature 0.7 -inch diameter unit made by Murata Erie North America. Inc. (2200 FIG. 1-A SIMPLE TONE -GENERATOR. Resistors R1 -R17 consist of Lake Park Drive. Sum -11a. GA 30080). The keyboard is a nothing more than lines drawn with a graphite pencil.

85 below the 555. After the three SMC's are in place. clip the UPPER PIEZO LITHIUM connection leads of the piezoelectric -buzzer element to a BATTERY Cl BUZZER TERMINAL BATTERIES 121 ELEMENT maximum length of 1.5 inches and remove 0.1 inch of insulation from the end of each lead. Attach the element to the upper right corner of the card with transparent tape. In^ Next, connect the pins of the 555 to the respective copper - grzic, foil conductors with small droplets of silver -filled ink. Apply 1411111 the ink with a sharp toothpick or piece of wire. Also apply 1.75" droplets of ink between the terminals of CI and the copper - foil strips on which Cl rests. Then form traces of conductive R1 - R17 ink between the terminals of RI8 and pins 6 and 7 of the 555. 4TftftfTer Use care when applying conductive ink. Too much ink will result in a short circuit should some of the ink run under the components. Be sure to follow any precautions supplied with SWITCH STRIP (SEE TEXT) the ink you select. 3.25" Next, form a path of conductive ink across the top of the 555 to interconnect pins 2 and 6. Then apply small droplets of conductive ink at the junction of each graphite resistor ElCOPPER FOIL (R1-R17) and the diagonal copper conductor. Also apply conductive ink at the junctions of the various copper foil ElCONDUCTIVE INK traces. Fasten the leads from the piezoelectric -buzzer element to FIG. 2-WHO NEEDS A PC BOARD? As show here, the entire circuit can be mounted on a piece of paper or cardboard, like a business card. the card with clear tape so that the exposed ends of its leads are positioned over the copper foil traces connected to pins 1 backed copper toil.Many kinds of conductive inks can be and 3 of the 555. Secure the leads to the foil with droplets of used. Silver -filled inks, however, will work best. Adhesive - conductive ink. backed copper foil is available from The Datak Corporation (3117 Patterson Plank Road, North Bergen, NJ 07047). Begin assembly of the circuit by using conductive ink and a suitable applicator (a wire or a sharp toothpick) to interconnect pins 4 and 8 on the back side of the 555. Set the 555 aside to allow the ink to dry. Next, follow the layout in Fig. 2 and apply adhesive - backed copper strips to a business card. Note that a single strip is placed along the upper left side of the back of the card. Cut an 18 -finger section from a length of the cylindrical - radius contacts to form the switch strip. Clip off the left -most flexible finger from the switch strip and slip the strip over the lower side of the card. Use a pencil to make a small mark directly below each contact finger, and then remove the switch strip. Use a multimeter to measure the resistance of lines drawn on paper with various kinds of pencils. While some pencils FIG. 3-THE AUTHOR'S PROTOTYPE. Pressing different contacts will produce non-conductive lines, others produce lines having an cause different pitched tones to be produced. easily measured resistance. Select a sharp pencil that produces lines having relatively low resistance to draw 17 paral- Afterthe conductive ink has dried,slip theswitch strip lel lines between the marks under the contact fingers and the over the bottom side of the card as shown in Fig. 2. Crimp the copper strip that runs diagonally across the lower center of the ends of the strip slightly to secure the switch strip in place. business card. Crimping will also insure that the switch strip makes good When the silver -filled ink on the lower side of the 555 is electrical contact with the copper trace applied to the left dry, attach the device to the card with a small piece of border of the card. reusable adhesive or wax. Then use very small pieces of the Cut a single finger from a length of cylindrical -radius same adhesive material to attach CI and R18 to the card at the contacts to form the upper battery terminal. Place a layer of locations shown in Fig. 2. Note that CI is mounted between tape under all but the end of the flexible -finger portion of the two thin copper strips while RI8 is simply attached to the card terminal. The tape is necessary to prevent a possible short should the edge of one or both coin cells make contact with PARTS LIST R1-R17-graphite pencil lines, see text the terminal. Crimp the clip -on portion of that terminal to the R18-1000 ohms, 1206 package upper -left corner of the card as shown in Fig. 2. C1-.01 p.F, 1206 package Figure 3 is a photograph of the completed circuit. Figure 4 IC1-555 timer, SO -8 package is a highly magnified view of a droplet of conductive ink over Miscellaneous: Lithium coin cells (2 each, 2016 or 2020 type), the junction of one of the graphite resistors and the diagonal piezoelectric buzzer (Murata -Erie MSJ-70383, or equivalent), switch strip (see text), battery terminal (see text), adhesive - copper strip. Figure 5 is a highly magnified view of CI. Note backed copper foil, conductive ink, graphite pencil, business that Fig. 5 also shows a droplet of conductive ink bonding one card, etc. continued on page 87

86 of the wires from the piezoelectric -buzzer element to its BUSINESS -CARD TONE GENERATOR respective copper strip.

continued from previous page Testing the circuit Carefully inspect the circuit to make sure no errors have been made. Then insert a stack of two lithium coin cells under the upper battery terminal (positive sides down). A tone should be heard when one of the switch -strip fingers (keys) is pressed against its respective graphite line on the surface of the card. Caution: Use care to avoid shorting the terminals of one or both coin cells. Lithium cells may explode when shorted. When the circuit works properly, try pressing each of the keys in turn. That test will illustrate the difficulty of drawing graphite lines having uniform resistance per unit length. The prototype circuit yielded a rather irregular sequence of tones as each key was pressed in ascending order. FIG. 4-A DROPLET OF CONDUCTIVE INK connects a graphite resistortO the copper strip. The circuit has no power switch. When the circuit is not being used, insert a slip of paper between the lithium coin cells and the upper battery terminal or remove the coin cells.

Going further Whether or not you choose to build this circuit, I hope the construction details presented here have given you some new ideas about the unique possibilities offered by combining surface -mountable components and conductive inks. While you might not wish to build miniature circuits on paper business cards, you can build such circuits on glass, plastic, wood, painted metal and many other substrates. In short, a circuit can be built on virtually any available surface. For example, the author has used silver -filled ink and SMC's to FIG. 5-A CLOSE-UP OF Cl. To its right, a droplet of conductive in 1( bonds build LED transmitter circuits directly on the battery holders one lead from the buzzer to a foil strip. that power the circuits. R -E

HAND -SOLDERING SMC's After all the components are in place, inspect the board to make sure each SMC terminal or pin is properly positioned. continued from page 72 You must then cure the board by preheating it long enough to drive off the volatile solvents from the paste or cream. The Solder paste or cream is offered in convenient syringe curing procedure is very important because it precludes the applicators by Alpha Metals and Multicore Solders. Figure 3 formation of unwanted solder balls and reduces the thermal shows a syringe of solder paste that contains 1.5 ounces of shock that that the board and its SMC's are subjected to 63%-tin/37%-lead solder paste. Note that when a paste or during reflow soldering. cream is supplied in that manner, it's generally necessary to IMPORTANT: Various solder pastes and creams may mix the material before use by rolling the barrel of the syringe require different curing times and temperatures. They may against a hard surface. After the needle is attached and the also require different reflow soldering times and tem- plunger is installed, a small quantity of material can be peratures. Therefore, it is essential to refer to the manufac- applied directly to each SMC footprint as shown in the turer's literature about a specific product to avoid unreliable opening of this article. solder connections. It's best to practice applying the paste on a piece of paper With that caveat in mind, a typical curing procedure is to first. That will allow you to learn how to cope with unforeseen heat the board in a convection oven for from 10 to 30 minutes situations such as how to deal with paste that continues to at 85°C. After the paste is cured, the board is removed and the emerge from the needle after you have coated a footprint. oven temperature is increased to the melting temperature of (Hint: Keep some paper towels handy.) the solder. The board is then placed back in the oven until the If the syringe method proves too tricky, you can apply the solder melts and then quickly removed. Alternatively, if the solder paste or cream directly to the terminals and pins of the board can withstand the temperature, it can be reflow sol- SMC's themselves using what is called the transfer method. dered by placing it on a hot plate. Another alternative is to use First, place some paste or cream on a clean, flat surface; a a desktop vapor -phase system such as Multicore Solders' glass microscope slide works well. Next, use tweezers to pick Vaporette. up an SMC and then dip its terminals or pins into the paste. Once again, it is essential to carefully follow the instruc- When all the terminals or pins are coated with a thin layer of tions for a particular solder paste or cream. Also, it's very the material, place the SMC on its footprints on the circuit important to avoid overheating the SMC's. Most, but not all. board. The sticky flux will hold the SMC in place while you SMC's can withstand the temperature of molten solder for 10 repeat that procedure for any remaining devices. seconds. R -E

87 the leads in place. Repeat that procedure for the leads from a LED FLASHER 9 -volt battery clip. Figure 4 shows the completed board. continued *ram pge 74 Testing the Circuit tion. Refer to the component placement diagram in Fig. 3 to Carefully inspect the completed circuit to make sure that make sure the 555 is oriented properly. Then solder each all the components are properly positioned. Pay particular terminal in place. attention to the orientation of the 555 and the polarity of the Continue assembly by installing the resistors and CI one at LED and battery clip leads. And be sure to remove any solder a time and soldering them in place as we've described. The bridges and balls. value of the resistors is given by a code in which the last digit The LED should begin to flash as soon as a 9 -volt battery is indicates the number of zeros. Thus the code 104 indicates a connected to the circuit. Operation of the circuit will be resistance of 10 followed by 4 zeros or 100,000 ohms. identical to that of a flasher made with through -hole compo- Install the LED next. For the utmost in miniaturization, nents. The thinness of the SMC flasher, however, means that you can use a chip LED. For high -brightness applications, it can be installed in previously unusable locations. And the use a leaded device. Cut the leads 0.2 inch from the LED, relative ease and speed with which it can be assembled should place them over their respective footprints (be sure to observe convince even the most skeptical builder that surface -mount polarity), and secure the LED in place with tape. Then solder technology is an idea whose time has come. R -E

circuit is complete, QI's leads will emerge from the board under LIGHT METER the battery -holder. Therefore, be sure to keep those leads close to continued from page 76 the board. Solder QI's leads to their footprints and clip off the excess lead lengths. Complete assembly of the board by installing the lithium coin - enced hand -solderer of SMC's, it is essential to carefully inspect cell holder on the underside of the board. Be sure to orient the each and every junction with a magnifying lens. holder so that its positive terminal (the uppermost battery con- Next, solder trimmer RI to the board. Since cementing RI to tact) is inserted in the hole marked + . Solder the terminals in the board might interfere with its rotor if you are not careful, it's place and clip off the protruding pins. Use caution; the clipped best to use a bit of masking tape to secure RI in place for terminals may fly away from your clippers with considerable soldering. force. If you want to use the circuit as a light meter, solder QI in place next. However, if you want to use the circuit for one of the Testing the circuit specialized applications that we'll describe later on in this arti- If you have installed QI, the circuit will function as a light cle, you should omit QI and, instead, solder a pair of stranded, meter when lithium cell BI is installed in its holder. LEDI will insulated hookup wires to its two mounting holes. glow to indicate the power is on. Use a jeweler's screwdriver to Note that QI is a conventional through -hole component. The adjust trimmer RI for the desired sensitivity. For best results, prototype used a tiny surface -mount phototransistor (Stettner perform the adjustment with the circuit in subdued light. Gener- Electronics CR IOTEI ). However, that meant that the phototran- ally, LED2-LED5 will switch off when Q1 is brightly illumi- sistor was aligned in the same direction as the readout. The result nated. Those LED's will then glow in sequence as the light was that someone viewing the readout could cast a shadow over reaching QI is progressively reduced. QI, affecting accuracy. You can switch the circuit off by removing B I. Or, you can slip To overcome that, the surface -mountable version of QI was a small piece of paper or thin plastic under, or a short length of replaced with a leaded phototransistor that can be installed heat -shrinkable tubing over, the uppermost battery -holder elec- facing away from the person viewing the readout. trode. The leads of the phototransistor are installed in two holes drilled in the circuit board adjacent to the negative battery holder Going further terminal. The emitter of QI, which is indicated by a small As noted previously, when QI is omitted the circuit can be protruding tab (see Fig. 4-a), must be installed in the hole used for other applications. For example, when a discharged connected to the negative battery -holder terminal. Therefore, capacitor is connected in the circuit in place of Q1, LED2-LED5 bend QI's leads as shown in Fig. 4-b and insert both leads will glow in sequence as the capacitor is charged by the small through the bottom side of the circuit board so that QI points voltage appearing at the common non -inverting inputs. One away from the circuit board as shown in Fig. 4-c. When the application for that configuration is as a timer whose period is determined both by the size of the capacitor and the setting of resistor RI. BEND LEADS AT EMITTER The timing intervals can be increased by increasing the value 1/4" RIGHT ANGLE > 1/4" EMITTER TAB of the capacitor. A new timing cycle can be started at any time by FROM BASE OF 01. momentarily shorting the capacitor. Another interesting application is to use the circuit to indicate resistance. When the input leads are open, all the LED's will glow. If a variable resistance is connected to the circuit in place of COLLECTOR QI, LED2-LED5 will glow in sequence as the resistance is 01 CIRCUIT BOARD lowered. We're sure that you have often wished for a visual (UNDERSIDE) continuity checker. Finally, keep in mind that the circuit as presented here func- b tions as a parallel array of inverting comparators. It can be FIG. 4-THE PHOTOTRANSISTOR'S EMITTER is indicated by the tab (a). revised to function as a parallel array of non -inverting com- When installing the device, bend the leads (b) and mount it so that it is parators simply by reversing the connections to the inputs of the pointing away from the circuit board (c). four comparators. R -E

88 SMT Resource Directory THE QUANTITY AND VARIETY OF SURFACE Dynaloy, Inc. Hexacon Electric Company mount components, supplies, literature, 7 Great Meadow Lane P.O. Box 36 and services has grown rapidly during the Hanover, NJ 07936 Roselle Park, NJ 07204 past few years. Here's a listing of sources GC Electronics and vendors for some of what is now avail- 400 South Wyman Street PACE, Inc. able. Many of these companies are repre- Rockford. IL 61101 9893 Brewers Court sented by local electronics distributors. Hysol Division, The Dexter Laurel, MD 20707 For additional information contact the Sur- Corporation face Mount Technology Association (Box P.O. Box 1282 1811, Los Gatos. CA 95031). Industry, CA 91749 Loctite, Electronics Division TOCLS SURFACE MOUNTABLE 705 North Mountain Road COMPONENTS Newington, CT 06111 Edmund Scientific Co. Amperex Electronic Corporation 101 E. Gloucester Pike George Washington Highway SOLDER PASTES AND CREAMS Barr ngton, NJ 08007 Smithfield, RI 02917 Jensen Tools, Inc. Alpha Metals, Inc. 7815 S. 46th Street Bourns, Inc. 600 Route 440 Phoenix, AZ 85044 1200 Columbia Avenue Jersey City, NJ 07304 Riverside, CA 92507 Multicore Solders, Inc. Pomona Electronics Exar Corporation Cantiague Rock Road Westbury. NY 11590 1500 E. Ninth St. 750 Palomar Avenue Pomona, CA 91766 Sunnyvale, CA 94086 SURFACE MOUNT SOLDERING EQUIPMENT CUSTOM CIRCUIT BOARD DESIGN Mepco/Centralab, Inc. 2001 West Blue Heron Blvd. Edsyn Inc. Analytic Design. Inc. Riviera Beach, FL 33404 15958 Arminta Street 320C ScottBlvd. Van Nuys, CA 91406 Santa Clara, CA 95054 Motorola Semiconductor Products, Inc. P.O. Box 20912 Phoenix, AZ 85036

muRata Erie North America, Inc. 2200 Lake Park Drive Smyrna, GA 30080 Surface

National Semiconductor Corporation P.O.Box 58090 Santa Clara, CA 95052 MOUNT NIC Components Corporation Artwork Patterns 6000 New Horizons Blvd. No. Amityville. NY 11701 11111111111 1111111

0 Signetics Corporation = - 1111111 e P.O. Box 3409 = e Sunnyvale, CA 94088 - 0% = - /e - 11111111111 e SMD Technology Service Center e 5855 North Glen Park Road Milwaukee, WI 53209 11111

...... , ...... I. .... Sprague Electric Company ......

P.O. Box 9102 I_ Mansfield, MA 02048 a % s. .. 11111 Stettner Electronics Inc. 1:: a . ' .10 ..= = 3344 Schierhorn Court ma t ... Franklin Park, IL 60131 It illir Texas Instruments JotDraftlm rub -down PCdrafting patterns now include a complete P.O. Box 809066 range of 4X, 2X and 1X SMD patterns conforming to the latest Dallas, TX 75380 industry practice and to IPC-SM-782. These rugged transfers include over 700 styles of donuts, connectors:, DIPs, letters, numbers and fabrication symbols. CONDUCTIVE INKS AND ADHESIVES The complete DATAKcatalog describes these and hundreds of other unique printed circuit products, dry transfer electronic titles, Amicon, A Grace Company drafting symbols, wiremarkers, and protective coatings. Write for 25 Hartwell Avenue it today! Lexington, MA 02173 DATAKCorp. 0 3117 Paterson Plank Rd. D N. Bergen, NJ 07047 CIRCLE 190 ON FREE INFORMATION CARD 89 Now electronics technicians can gel into VCR Servicing quickly and easily Learn professional VCRservicing at home or in your shop with exclusive videotaped demonstrations Today, there are more than10 million VCRs in use, with people standing in Covers Beta and VHS line to have them serviced. You can bring this profitable business into your systems with actual shop with NRI professional training in VCR servicing. This top-level training instruction on supports the industry's claim that videotape. the best technicians today are those who service VCRs. Integrated Three -Way Self -Teaching Program In one integrated program, NRI gives you a study guide, 9 instructional units, 2 hours of video training tapes accompanied by a 32 -page workbook that pulls it all together. At home or in The Best Professional Professionals. Examine it for 15 full your shop, you'll cover all the basic days, look over the lessons, sample the concepts of video recording, mechani- Training videotape. If you're not fully satisfied cal and electronic systems analyses, course has that this is the kind of training you and and the latest troubleshooting tech- This exclusive self -study beendeveloped by the professionals at your people need to get into the profit- niques. Your workbook and instruction- able VCR servicing business, return it al units also contain an abundance of NRI. NRI has trained more television technicians than any other electronics for a prompt and full refund, including diagrams, data, and supplementary school! In fact, NRI has consistently postage. Act now, and start adding new material that makes them valuable addi-led the way in developing troubleshoot-business to your business. tions to your servicing library. ing techniques for servicing virtually The "How -To" Videotapeevery piece of home entertainment Special Introductory Offer equipment as it appears in the market- This complete VCR training course Your NRI Action Videocassette uses place. every modern communications tech- with two hour videotape is being nique to make learning fast and easy. Satisfaction Guaranteed offered for a limited time only, on You'll enjoy expert lectures and see orders received from this ad, at our low animation and video graphics that make ...15 -Day No -Risk introductory price of $179.95. Save every point crystal-clear. You'll follow Examination $20 by acting ndw! the camera eye into the heart of the NRIRaining For Professionals Send today for the new NR1 Self - McGraw-Hill Continuing Education Center VCR as step-by-step servicing tech- StudyCourse in VCR Servicing for niques are shown. Both electronic and 3939 Wisconsin Avenue WashinaT, DC 20016 mechanical troubleshooting are covered SI Getme started in profitable RI NRI Training For Professionals ... including everything from complete replacement and adjustment of the VCR servicing. Rush me my McGraw-Hill Continuing recording heads to diagnosing micro- NRI self -study course in VCR Servicing for A Education Center processor control faults. Professionals. I understand I may return it for rr, 3939 Wisconsin Avenue a full refund within 15 days if not completely Washington, DC 20016 Plus Training On All The satisfied. 1 I New Video Systems PLEASE SPECIFY TAPE FORMAT DESIRED 0 VHS 0 BETA Althoughyour course concentrates Name (please print) on VCRs covering Beta, VHS, and'/ Company

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BUILD THE PT -68K learng 68000 computing in the CD Classroom

GERNSBACK PUBLICATION CONTENTS COMPUTER NOVEMBER DIGEST Larry Steckler, EFIF, CET: publisher & editor in chief

Art Kleiman, 1987,4N. editorial director Brian C. Fenton, managing editor Jeff Holtzman technical editor Byron G. Wels, associate editor Carl Laron, associate editor Robert A. Young, assistant editor Ted Scaduto editorial assistant Ruby M. Yee, 95 TURBOCHARGE YOUR PC production director How to and how much Karen Ricker, production advertising Robert A. W. Lowndes, production associate Marcella Amoroso production assistant Andre Duzant, technical illustrator Jacqueline P. Cheeseboro circulation director Arline R. Fishman, advert sing director

ComputerDigest 101 CD CLASSROOM, PART 2 Gernsback Publications, Inc. Start construction this month 500-B Bi-County Blvd. Farmingdale, NY 11735

ADVERTISING SALES 516-293-3000 Larry Steckler Publisher

NATIONAL SALES Joe Shere 1507 Bonnie Doone Terrace Corona Del Mar, CA 92625 714-760-8697 93 EDITORS WORKBENCH Fall reading list Cove' Photography by Herb Friedman PC -601 Bus extender and Andre Duzant A86/D86 Assembler/debugger MIX C-Integrated development environment

92 EDITOR'S

WORK-

mation that's hard to come by elsewhere. Inc., Greensboro, NC). The irony is that More comprehensive is 68000 Assembly Compute! magazine is a traditional 6502 Language Programming by Lance A. Le- stronghold-but don't let that bother you; BOOKS venthal, Doug Hawkins, Gerry Kane, and the book is chock full of charts, tables, and William D. Cramer (c. 1986, Osborne example programs showing you how to get McGraw-Hill, 2600 Tenth Street, Berkeley, at your machine's capabilities from both CA 94710). The book contains in-depth BASIC and assembly language. It's not for treatment of the 68000, additional informa- beginners, but you needn't be an advanced tion on the 68010 and 68020, and much systems designer either. Highly recom- advanced information on topics like inter- mended. rupts, debugging, and program design. An Beginners will, however, find appendix lists all microprocessor instruc- Understanding MS-DOS by Kate O'Day (c. Portable Correction tions in an easily referenced format showing 1987 by The Waite Group, Howard W Sams the assembly -language syntax, each instruc- & Co., Inc., 4300 West 62nd Street, Indi- tion's bit -field format, flags affected, textual anapolis, IN 46268) useful. The book uses iNur article on portable MS-DOS ma- description, and version-specif c variations color, typeface, and illustration well to chines (in the September issue) con- (68020, for example). brirg out important points. Topics include tained several errors regarding the DataVue 6502, 65802, and 65816 fans will want to basic DOS commands, subdirectories, 25. First, the machine is not AC -only; an check out 65816/65802Assembly Language hard -disk management, batch processing, external battery pack is available that will Programming by Michael Fischer (c. 1986, etc.; each chapter includes a quiz to help run the machine for about two hours. Sec- also published by Osborne McGraw-Hill, re-inforce your knowledge. ond, the DataVue 25's backlighting is not address above). A brief introduction sum- Users at all levels will find IBM PC & PC XT electroluminescent, but fluorescent. Last, marizes microprocessor evolution since the User's Reference Manual by Gilbert Held (c. the machine's hard disk has a capacity of 20 early 1970'5; the book then goes on to dis- 1987, Hayden Books, Howard W. Sams & megabytes, not 10 megabytes, as reported. cuss the 65xxx family architecture, and then Co., Inc., 4300 West 62nd Street, Indi- In addition, contrary to what was stated in focuses on the advanced members of the anapolis, IN 46268) valuable. Topics in- the article, itis possible to boot from the family There are many example programs, clude system set-up, DOS operations, hard disk. We apologize for the errors and and appendices include hardware data elementary and advanced BASIC, graphics, thank Peter Baron, a DataVue press agent, for sheets for most major members of the batch files, etc. When I forget the syntax of a pointing them out. 65xxx family command, I often find myself reaching for For Intel fans, 80386/80286 Assembly this book before the appropriate Microsoft Language Programming by William H. Mur- or IBM manual. ray III, and Chris H. Pappas (c. 1986, Os- Back -To -School Booklist borne McGraw Hill, address above) wi II be Apple and IBM clone boards indispensable reading. The book begins IluScope Associates (PO. Box 790, with several chapters of introductory mate- Lewiston, NY 14092) publishes several atever your interest-80xxx, 680xx, rial; chapter three gets into the 286/386 ar- manuals with information on building Ap- or 65xxx systems, you'll find one of chitecture, and is full of comparisons with ple II and IBM PC and AT motherboards, the books listed here useful. First we'll dis- the 8088/86. It then goes on to examine the pehpheral cards, etc. We examiend the IBM cuss several assembly -language primers for 80287/80387 math co -processors, various book. It's divided into two parts, the first of various systems, followed by several tomes assemblers, and other topics. Instruction which contains basic construction informa- specific to the IBM PC. sets of each processor and co -processor tion, resistor color -code tables, etc. The are listed, and an appendix provides infor- second part is divided into eight sections For hackers only mation on how to maintain a library of that focus on building several models of Leo Scanlon's The 68000: Principles and often -used routines. each of the following types of boards: Programming (c. 1981, Blacksburg Con- motherboard, disk controller, memory, vid- tinuing Education Series, Howard W Sams IBM PC eo, multifunction, serial/parallel, mis- & Co., Inc., 4300 West 62nd Street, Indi- One of The most useful books I've seen cellaneous, and prototype. Information on anapolis, IN 46268) provides a good, brief on the internal workings of the IBM PC is each board includes parts layout, parts list, introduction to the 68000. One highlight is Compute's Mapping the IBM PC, by Russ and a few notes. It's definitely not for begin- chapter 6, which includes hardware infor- Davies (c. 1986, Computer! Publications, ners..CD.

93 Shareware Assembler/Debugger, shown at all times. Now that A86 is Microsoft compatible, Eric Isaacson and the documentation has been cleaned up, our main complaint with the package is that you can't load or save files from within 0088 assemblers are notoriously difficult D86 (as you can with DEBUG); you must 11gPto use because of the amount of specify the file name on the invoking com- "housekeeping" the programmer must do mand line. But we expect that file problems even to assemble a simple program. Begin- will be fixed when D86 is upgraded. ners are turned off because learning how to CIRCLE 23 ON FREE INFORMATION CARD use the assembler may be more difficult than learning the assembly language! PC -601 Bus Extender, Chenesko Eric Isaacson took that problem seriously MIX C Compiler, Editor, Debugger Products and wrote a fast, easy -to -use assembler (A86) and an accompanying full -screen symbolic debugger (D86), shown in Fig. 2. circuit development for the IBM PC bus is The package has gone through several incar- compilers that operate in an integrated whindered by a myriad of merely physical nations; early versions could not assemble wenvironment have been around for problems, including getting at bus signals Microsoft assembler source files, but ver- some time, but one that has been evolviiig for examination with a scope or logic ana- sions of the assembler greater than 3.00 are for several years is marketed by Mix Soft - lyzer, wiring (and modifying) circuits on expansion cards, etc. The PC -601 (shown in Fig. 1) solves the problem by bringing the START. Fl. SingStep F2 ProcStep Up,Down move bus out to a solderless breadboard station 8188 MOV AN,8 F3 lepeaterd F4 TrapJmp 1P -cursor 8182 INT 821 FS F6 TrapRet with more than 3000 tie points. A half- 0184oneAL,3 F7 PatchMes F8 length card with several buffers is inserted 8106 JNE MORE F9 FIB Altilindoke 8108 INT 828 in your PC; a two -foot length of ribbon ca- MORE. 1 -letter commands are debugger commands ble connects it to the breadboard box, 810A CALL DORM II -letter: see -execute A86 instructions which contains built-in ±5 and ±12 volt 8188 BM? START digits 1--6 open memory windows DOBYTE. F18 gives other help windows power, a scope multiplexer that allows a 818F PUSH AX single -channel scope to display as many as 8110 MOV CL,4 0112 Dill AL,CL four signals simultaneously, buffered ad- 8114 CALL CONVRT dress, data, and control lines, and provi-

AX 8861 i z e 1: BX8888 IP8184 2! CX 88FF CS 2D83 3: DX 2D83 SS 2083 4: SI 8188 DS 2883 5: DI FFFE ES 2883 6' BP 0882 SP FFFE

FIG. 2 now mostly Microsoft compatible. (We are ware (1132 Commerce Drive, Richardson, TX still waiting for version 3.00 of the debug- (800) 523-9520). It combines a split-screen ger.) Documentation has also improved WordStar -like editor, a quality C compiler, considerably since the early versions. All and a windowed Trace utility, which allows programs and documentation fit in several source -level debugging. Each program is ARC files on a single floppy disk. Many BBS's available separately; the three can be pur- (including ours, (516) 293-2283, chased together discounted. CP/M and MS- 300/1200,8,N,1) carry the ARC files; you can DOS versions are available. also order them directly from the author at The editor is highly configurable, allow- 416 E. University St., Bloomington, IN 47401, ing you to define keyboard controls and FIG. 1 (812) 339-1811. Evaluation copies are free; macros. In splitscreen mode, you can edit registration costs $40 for either A86 or D86, two files simultaneously, transferring text sions for daisy chaining additional PC -601's. or $70 combined. between them. Construction quality of the internal PC D86 can be used on any .COM file, but to The compiler itself is highly compatible boards is excellent; the molded plastic do symbolic debugging, the file must have with the Kernighan and Ritchie standard; case should stand up to rugged shop use. been assembled with A86. One nice fea- Mix includes special utilities to either com- Wiring up I/O or address -decoding circuit- ture of A86 is that it generates code for the press or speed up programs created with ry is easy because the address, data, and 8088, 8086, 80286, 8087, 80287, and sever- the compiler The manual contains a tutorial control lines are brought out to pin sockets. al NEC V -series microprocessors. 80386 that should help intermediate programmers A 16 -page manual provides clear installa- code is not included in the present version. get up to speed quickly tion and usage instructions; schematics for In D86, you press Fl to execute a single The real gem of the package is the Trace the switching power supply, scope multi- instruction, or F2 to execute a subroutine. In utility, which includes a faster (and larger) plexer, and buffer circuitry are also in- addition, you can enter assembly -language version of the compiler. Trace allows single - cluded. code, referencing your program's symbols, stepping, tracing, and fullspeed tracing. It The PC -601 lists for $369.95; contact Che- if desired. An extensive set of memory dis- also allows you to set up as many as four nesko Products, Inc., 21 Maple Street, Cen- play commands allow you to set up as windows to display source code, program tereach, NY 11720, (516) 736-7977 for more many as six multi -format views into any de- output, and variable values simultaneously information. sired area of memory The micropressor's Mix C is hard to beat CIRCLE 22 ON FREE INFORMATION CARD registers, flags, and the top of the stack are CIRCLE 24 ON FREE INFORMATION CARD

94 111001Aft41 Pr JEFF HOLTZMAN, TECHNICAL EDITOR

C peed-you can never get enough. At last count there were accelerator card to provide a compatibility mode; in other cases 431about eight million K's, XT's, and clones out there, and we'd be compatibility is achieved by running the accelerator's micro- willing to bet that most of the people using those machines would processor at a slower speed. Replacement processors usually are jump at the chance to get them running faster. Programs for CAD, built around 80286 IC's, but some are built around 8086's. Most circuit design and analysis, desktop publishing-they all work early replacement processors ran at 8 MHz; many now run at 10 or better when the computer thinks as fast as you do. even 12 MHz. But how do you increase the speed of a PC, XT, or clone? When A co -processing accelerator adds what amounts to a second, you look into it, you quickly find that there is a bewildering variety of fully independent, computer to your PC. Some co -processing ac- choices available, ranging in price from about $10 to about $1500- celerators can actually function at the same time as the host's more than a full-blown PC or XT! microprocessor, allowing you to work on completely independent Does a $10 upgrade provide any significant advantage? At the tasks simultaneously. other end of the price spectrum, is a high-speed 386 -based moth- There exists a fourth and increasingly popular way of speeding erboard worth as much as-or even more than-the original pur- up your PC: replacing your motherboard. Replacing it can provide chase price of a piece of equipment? most of tne advantages of the previous methods, with few of their The answer depends on what your needs are and on your disadvantages. We'll examine at least one of each type of acceler- previous equipment investment. But before we try to provide the ator option in what follows. answer, let's talk about each of the upgrade solutions and examine some hard data. Later we'll show how the numbers don't tell the Test strategy whole story. The hardware we tested is summarized in the sidebar To test compatibility, we attempted to run the following software on page 100 alphabetically by manufacturer. on all hardware: WordStar 4.0, AutoCad 2.6, AutoSketch, VP Planner, Microsoft Windows 1.03, PageMaker 1.0a, and Direc-Link. All tests Accelerator basics were performed under PC -DOS 3.30. Each piece of hardware ran Basically, there are three types of accelerators: clock -speed en- each program without problems, although in some cases firmware hancers, replacement processors, and co -processors. The usual (EPROM's, PLD's, etc.) upgrades were necessary. clock -speed enhancer is what we call an octopus board, a small PC We ran the Computer Digest interpreted -BASIC benchmarks on board that does not require an expansion slot, but rather dangles each piece of hardware, except Hauppauge Computer Works' 386 over the motherboard and somehow injects a faster clock signal motherboard, so it is not included in the quantitative results. The into it. Octopus boards have one or more "tentacles" that must benchmark consists of five tests, including sequential disk read and connect to various points on the motherboard, both to pick up write, integer math, floating-point math, and screen write. Except z signals and to insert them. for the reolacement motherboards, all tests were run on a standard0 A replacement processor is a full- or half-length card that re- IBM PC XT. Except for boards with built-in display adapters, all rn quires an expansion slot. You must remove the host computer's boards were tested with a Hercules monochrome card; those with 8088 microprocessor from its socket and connect the vacant socket built-in adapters were tested in Hercules emulation mode. Those to the accelerator card via a 40 -conductor ribbon cable. In some boards were also tested in EGA mode for comparison. Last, the co cases the host computer's 8088 microprocessor is installed on the disk -speed tests were all run on the same hard -disk drive. CO

95 TABLE 1 -SPEED COMPARISON

Machine Abbrev Disk Disk Integer Float Screen Speed Price Write Read Math Math Write Factor IBM PC XT XT 42.3 28.7 32.0 33.3 31.0 100% $0 IBM PC XT (V20) V2 40.3 29.0 30.0 31.7 28.3 105% $12 NickeIX (7M,V20) N7 26.7 18.0 17.3 19.0 17.3 170% $70 NickeIX (8M,V20) N8 27.0 16.0 16.0 18.0 17.0 178% $70 MCT Turbo MC 29.7 18.0 18.3 20.3 20.0 157% $130 Mach 10 M1 29.7 20.0 16.3 20.0 19.3 159% $399 Breakthru 286 B2 14.3 9.0 5.3 7.7 10.0 361% $595 Tiny Turbo TT 19.0 13.7 11.0 12.0 20.0 221% $595 TurboEGA TE 21.3 13.7 11.7 11.0 14.0 233% $749 286 Rainbow Plus RB 25.3 16.0 25.7 28.0 20.7 145% $945 PCTurbo 286e-8 PT 11.3 9.3 7.0 8.0 6.0 402% $1,195 SOTA MB 5.0 SO 10.0 7.0 6.0 6.3 9.3 433% $1,295

45 The numbers The raw numbers obtained are shown in Table 1, which is sorted by price. The first entry is our base test machine, an XT with a 3.5 Miniscribe hard disk (100 -ms average seek time). Figure 1 shows the speed -test data graphically. (Refer to Table 1 3 for the meanings of the abbreviations on the horizontal axis.) The shorter the overall height of each bar, the faster the overall speed. 2.5 From that graph you can see that SOTA's MotherCard 5.0 is the fastest, followed closely by Orchid's PCturbo 286e, and then by 2 PCSG's Breakthru 286.

1.5 Figure 2 plots speed factor (from Table 1) vs. cost. In general, as you would expect, greater speed costs more. However, there are several exceptions, the most significant of which is the PCSG board $0 $70 $130 $595 $749 $1,195 (labeled B2), which provides about 85% of the performance of the XT N1 MC B2 TE PT fastest boards, at about 50% of the cost. $12 $70 $399 $595 $945 $1,295 What follows are our comments derived from installing each V2 N8 M1 TT RB SO piece of hardware, running the quantifying benchmarks and the NOTE: SEE TABLE 1 FOR ABBREVIATIONS compatibility -test software, and impressions. The com- FIG. 1 -Performance Comparison Chart ments are presented in alphabetical order by manufacturer or distributor.

200 -

150

0 L.)

O 1 50 I I= I MN.4M I IMME vi 1.1 Eigmimam irwrA,A AIrI' A IrII"A XT Ir V2 N7 N8 MC M1 B2 TT TE RB PT SO MACHINE

DISK WRITE DISK READ INTEGER MATH [IMOFLOAT MATH SCREEN FIG. 2-Price/performance Comparison Chart

96 386 Motherboard Hauppauge Computer Works got its start selling math co -processor speed-up kits; the 386 Motherboard (shown in Fig. 3) is designed as a replacement for a star idard PC or XT motherboard. After dismantling your PC, you install the new motherboard, re- insert your old expansion cards, and you're off into the world of truly high-speed computing. Due to a shortage of boards, we were unable to perform an actual installation and run our benchmarks, but the company was kind enough to allow us to run our compatibility software on a test board in their engineering laboratory We also installed and successfully ran several pieces of expansion hardware, including our favorite digitizing tablet, Pencept's Penpad 320, which uses a 68000 co -processor. Subjectively, the 386 Motherboard ran all software frighteningly fast. AutoCad and PageMaker screen redraws happened nearly instantaneously In fact, with a 387 math co -processor installed, AutoCAD was able to redraw a test screen in twelve seconds; the same redraw on an un-enhanced PC takes over four minutes!

Nickel Express and Turbo Motherboard JDR Microdevices markets a number of IBM -type expansion and enhancement products, including the Nickel Express (shown in Fig. 4) and the MCT-Turbo, an 8 -MHz XT motherboard (shown in Fig. 5). Like the 386 motherboard, the MCT-Turbo is a direct plug -compatible replacement for a standard XT motherboard; it may also be used as the brains of a build -it -yourself clone. It includes an 8088-2 microprocessor that you can run at either 4.77- or 8.0 -MHz. Speed is selectable by means of a shorting jumper plug located near the keyboard connector at the rear of the board. The board's documentation claims that speed is also keyboard selectable, but the keystrokes mentioned had no effect on speed. FIG. 3-Haupr auge's 386 Motherboard The MCT-Turbo accepts 36 4164 RAM IC's, for a total of 256K of memory, or by moving a jumper, two banks can be filled with 41256 IC's for a total of 640K. In addition, seven sockets are provided for EPROM's, one of which is occupied by the MCT BIOS EPROM. The MCT-Turbo comes with a thin User's Manual that contains a brief theory of operation, complete schematics, switch settings, and troubleshooting hints. An additional loose-leaf page discusses installation. After setting up the board, we installed our XT's hard disk and controller in it, and then ran our compatibility and benchmark tests. We also tested several pieces of expansion hardware; the only problem we experienced was with a CGA card that had trouble running at the faster speed, and caused our monitor screen to display snow in some, but not all, circumstances. The Nickel Express is an octopus board. To installit you must FIG. 4-JDR's Nickel Express remove the 8284 clock IC from your motherboard and then insert a short 16 -conductor ribbon cable into the vacant socket. The other end of the cable plugs into a socket on the small (approximately 2" x 3") circuit board, which contains two clock IC's, a PLD, three crystals (corresponding to the board's three speeds: 6.66-, 7.37-, and 8.0 -MHz), and several jumpers and discrete components. In addition, speed -selection and reset switches are provided. The board and switches are mounted on a sheet -metal housing that clips on the outside of the rear panel of your PC, thereby providing a reasonably stable mounting scheme. An additional wire may be attached to an IC on the motherboard to allow software speed selection. In that respect the Nickel Express is "cleaner" than most octopus boards. To use the Nickel Express you have to find the maximum speed at which your motherboard will run. Unfortunately, trial and error is the only way to do so. To run the board at maximum speed, you must run a small program that becomes memory -resident and thereafter slows down the clock whenever the floppy disk is accessed. The test results shown in Table 1, Fig. 1, and Fig. 2 are with the FIG. 5-JDR's MCT-Turbo Nickel Express running at the two highest speeds with an 8 -MHz NEC V20, which is included in the purchase price. Mach 10 The board comes with a slim installation manual that provides Microsoft sells the Mach 10 (shown in Fig6), a replacement detailed installation instructions and some theory of how the board processor, in two configurations: the board alone, or bundled with works. It's not fancy, but it gets the required information across. a mouse and Microsoft Windows. In either case, the accelerator

97 FIG. 6-Microsoft's Mach 10

board runs an 8086 at 9.54 MHz, twice normal speed. To install the Mach 10, you set some jumpers, remove the CPU from your motherboard, connect a ribbon cable from the CPU socket to the Mach 10 board, and insert the board into an unused full-length expansion slot. The jumpers determine the mouse's interrupt, caching of BIOS and BASIC, (some programs may not run FIG. 7-Orchid's Tiny Turbo when the BIOS or BASIC is cached) and 8087 presence. The rear - panel mounting bracket has a socket for the mouse, a toggle switch for changing speed, and a socket for an optional speed -select switch that lights up when in turbo mode. The optional switch is nicer than most speed -select switches because it is mounted at the end of a cable, so you don't have to reach behind your PC to change speeds. It's also nicer than most switches (and more convenient than some software speed switches) because you can change speed at any time (after booting) without causing a reboot. Installation is a snap; documentation is excellent. The only thing FIG. 8-Orchid's TurboEGA we don't like is the use of Microsoft's Inport mouse connector. The problem is that when you outgrow the Mach 10, the mouse may reboot. Documentation is contained in a clearly written 12 -page end up being useless, because few third -party vendors support it. booklet. Use of a standard serial mouse would have provided more options The next model up, the TurboEGA (shown in Fig. 8), combines as your needs change. the performance increase of the Tiny Turbo with a built-in multi - Microsoft will be releasing another accelerator board (286 - mode EGA adapter. The TurboEGA is a full-length card with an based) called the Mach 20; however, we were unable to obtain 80286, an 80287 socket, a reset/speed-select switch, and the EGA one in time for this article. adapter, which also has modes that emulate CGA and Hercules monochrome text and graphics. The figures presented in Table 1, NEC V20 Fig. 1, and Fig. 2 are with the board running in Hercules emulation The least expensive accelerator option provides a modest in- mode; in EGA text mode, screen output speed is about 15% faster, crease in speed-about 5%. Installation is as simple as swapping due to Orchid's optimized EGA BIOS. IC's; there are no jumpers, DIP switches, or memory -resident soft- Installation amounts to setting jumpers and DIP switches for ware programs to contend with. Compatibility is high, but not monitor type (color, monochrome, or EGA) and number (the Tur- perfect; we've seen a number of programs that won't run on a V20, boEGA can co -exist with either a CGA or a monochrome adapter), including a version of GW-BASIC, a compiled Turbo Pascal CAE co -processor speed, memory size, and cache enable/disable. The program, and several games and educational programs. Consider- host 8088 is inserted into a socket on the TurboEGA's board, which ing the price, however, it can't hurt to try a V20, especially if you're is then connected to the vacant motherboard socket via a 40 - on an austere budget. conductor ribbon cable. The mounting bracket has a speed-select/reset switch, a nine -pin Tiny Turbo, TurboEGA, and PCturbo 286e D connector (for the monitor), access to the monitor -select DIP Orchid Technology has been in the accelerator -board business switch, and RCA jacks for the EGA's auxiliary outputs. longer than anyone else, and the quality of their boards, some of Documentation consists of a small spiral -bound manual; the which have been reviewed here before, reflects that longevity manual is well written and well produced. A diskette is included We've had minor complaints with their documentation and tech- that contains programs to turn monochrome and CGA emulation on nical support, but we have since found that in those regards, and off, a program to display the BIOS ROM's date (the TurboEGA Orchid is at least as good as the competition, and in many cases will not work on IBM PC's with ROM's dated before 10/27/82; the better. ROM can be upgraded), and a screen saver. The least expensive board is the Tiny Turbo, shown in Fig. 7. It is a Unlike some multi -mode display adapters, Hercules and CGA half-length replacement processor that contains an 80286 pro- emulation work fine on the TurboEGA. cessor running at 7.16 MHz, and an 80287 math co -processor Orchid's PCturbo 286e (shown in Fig. 9) is available in 8- and 10 - socket. To install the board, several jumpers must be set; the MHz versions; we tested the 8 -MHz version, which is faster than jumpers indicate co -processor speed, amount of system memory, most 10- and 12 -MHz accelerator cards. The 286e is a co -processor and cache enable/disable. The host's 8088 is inserted on a small card that plugs into the expansion bus and has no electrical con- daughterboard to which the 40 -conductor ribbon cable attaches. nections with the host 8088. The 286e really consists of a complete A toggle switch that protrudes through the board's mounting computer on a card, with its own, separate 16 -bit 1 -megabyte bracket selects fast (80286) or slow (8088) mode, and also func- address space. An additional megabyte of RAM can be added via tions as a reset switch. Changing speeds forces a complete system an optional daughterboard; that RAM can be configured as ex -

98 conjunction with the host PC, various kinds of memory (EMS, protected, DOS), installation instructions, memory maps, jumper settings, and information on using the utility software. For all its power, the 286e is not without problems. For example, it is incompatible with third -party EGA cards, although a special EGA adapter is available from Orchid that is compatible. In graphics mode on a Hercules card, random "garbage" is often left on the screen; the garbage disappears, however, merely by moving the pointirg device (mouse or digitizing tablet) in the affected area. And the way the manual intersperses technical with installation and FIG. 9-Orchid's PCturbo 286e-8 operat.onal informat on is confusing. On the plus side, we used the board for a long period of time as panded or extended memory The board also has a socket for an the basis of a high-performance AutoCAD system. The 286e co- 80287 co -processor. existed peacefully with a multi-function/EMS board made by Ap- Until recently, the 286e was simply the fastest accelerator card parat (the Limbo II, reviewed in the March 1987 issue). In a different you could buy A good deal of the card's speed is due to tne fact configuration, it also functioned with a 68000 co -processor board that it copies the host's BIOS and BASIC ROM's into its owr 16 -bit that controls Pencept's Penpad 320 digitizing tablet. Not counting address space. the video controller, that made a total of three microprocessors In turbo mode, programs are executed on the 286e's 80286 running simultaneously inside a standard IBM PC XT! All in all, there's microprocessor; in standard mode, programs are executed on the a great deal to like about the PCturbo 286e. host's 8088 microprocessor. In addition, it is possible to configure the system so that the 8088 and the 80286 execute programs Breakthru 286 simultaneously In fact, you can add as many as four 286e cards to a The Personal Computer Support Group has been around a long single PC and operate each one independent of the others. time supplying enhancement products for Radio Shack's portable Installation consists of setting I/O port -select jumpers, interrupt computers, particularly the Model 100 and the Tandy 102. A few line, 80287 interrupt and speed, and on -board memory Then you years ago, the company got into the PC business with an excellent must run a special installation program that configures the software disk cache program called Lightning; their first hardware entry is the that switches between turbo and normal modes. At that point a Breakthru 286, whicn comes in 8- and 12 -MHz versions; we re- new AUTOEXEC.BAT file is created, and two new boot batch files. viewed the latter, which is shown in Fig. 10. Every board comes with One contains the contents of your old AUTOEXEC.BAT; the other, a copy of Lightning, the program is also available separately for any additional commands to be executed solely by the 286e. Any $89.95. commands in the (new) AUTOEXEC.BAT file are then executed by Like Orchid's Tiny Turbo, the Breakthru 286 is a half-size replace- both the 8088 and the 80286; commands in the other boot files are ment processor. Unlike the Tiny Turbo, however, you remove and executed only by the appropriate processor That allows you, for store your PC's 8088 (and 8087, if present); the 8088 does not example, to set date and time only once, say in the 8088's file. A mount on the Breakthru's board. In addition, a special plug must be separate TURBO.SYS file is also created; it performs the same func- inserted in the 8087 socket on your PC's motherboard. The Break- tion as CONFIG.SYS does for the host. thru has a socket for an 80287. Installation continues by setting a Several useful utility programs are included: a RAM disk, a disk switch on your motherboard and configuring several jumpers on cache, and a print spooler Typically you'll spend most of your time the Breakthru. In addition, you may add a device driver to your (and run your programs) in turbo mode, and use the 8088's address CONFIG.SYS file; the driver allows you to change speed from the space for the RAM disk, cache, and spooler All three programs are keyboard, and to set the hot -key combination that accomplishes extremely useful and reliable, and greatly contribute to overall speed switching. Alternatively, you can use Lightning to accomplish speed and convenience. speed switching and to set the hot key. You can switch speed at any The 286e's manual is in Orchid's standard spiral -bound =orm. It time without causing a reboot; a special Lightning command will contains a fair amount of information about how the 286e works in force clock speed to be reduced whenever a floppy disk drive is accessed. Compatibility Software Separate manuals are provided for Lightning and the Breakthru. The Breakthru's manual is somewhat confusing, due to inconsistent PageMaker, Aldus Corp., 411 First Avenue South, Seattle, WA use of the term cache. For example, to place the Breakthru in turbo 98104, (206) 622-5500. mode, at the DOS prompt you type A > L CACHE ON. But to set up a CIRCLE 38 ON FREE INFORMATION CARD 64K disk cache for drive C, the command is A> L 64 C. After overcoming the terminology, however, everything works well. In AutoCad 2.6 and AutoSketch, Autodesk, Inc., 2320 Marinship addition, lightning automat cal ly senses the presence of EMS mem- Way Sausalito, CA 94965, (800) 445-5415 CIRCLE 39 ON FREE INFORMATION CARD ory, and can use as much as 1.5 megabytes of it.

WordStar 4.0, MicroPro International, PO. Box 7079, San Rafael, CA 94901-0079, (800) 227-5609, (800) 343-3000 ext. 655. CIRCLE 40 ON FREE INFORMATION CARD

Windows, Microsoft Corp., Redmond,.X,//t, 98073, (800) 426-9400, (206) 882-8088 (WA) CIRCLE 41 ON FREE INFORMATION CARD

Direc-Link, Micro -Z Company, 4 Santa Bella Road, Rolling Hills Estates, CA 90274, (213) 377-1640. CIRCLE 42 ON FREE INFORMATION CARD

VP Planner, Paperback Software, 2830 Ninth Street, Berkeley, CA 94710, (415) 644-2116. CIRCLE 43 ON FREE INFORMATION CARD FIG. 10-PCSG's Breakthru 286

99 Hardware Manufacturers and Distributors

386 Motherboard, Hauppauge Computer Works, Inc., 358 Veterans Memorial Highway, Commack, NY 11725, (800) 443-6284, (516) 360-3827 (NY). CIRCLE 27 ON FREE INFORMATION CARD

MCT-Turbo and Nickel Express, JDR Microdevices, 110 Knowles Drive, Los Gatos, CA 95030, (800) 538-5000, (408) 866-6200 (CA). FIG. 11-PC Technologies'286 Rainbow Plus CIRCLE 28 ON FREE INFORMATION CARD

Mach 10, Microsoft Corp, Redmond, WA 98073, (800) usage was critical 426-9400, (206) 882-8088 (WA) CIRCLE 29 ON FREE INFORMATION CARD MotherCard 5.0 The flat-out winner in terms of overall speed, State Of The Art NEC V20, NEC Electronics, Inc., 401 Ellis Street, PO. Box Technology's 12.5 -MHz MotherCard 5.0 (shown in Fig. 12) basically 7241, Mountain View, CA 94039, (800) 632-3531, (800) packs an AT onto a single expansion card. Like the PCturbo 286e, it 632-3532 (CA). is a co -processor, but unlike that card, the MotherCard requires the CIRCLE 30 ON FREE INFORMATION CARD 8088 to be mounted on it, and a ribbon cable to connect to the Tiny Turbo, TurboEGA, and PCturbo 286e, Orchid host. 8- and 10 -MHz versions of the card are also available. Technology, 45365 Northport Loop West, Fremont, CA 94538, The board features a "re -configurable" BIOS, actually a battery- (415) 683-0300. backed CMOS RAM that may be used to patch BIOS updates. The CIRCLE 31 ON FREE INFORMATION CARD company claims that IBM's forthcoming OS/2 will run on the board, but was unable to verify that by press time. (The 5.0 in the name Breakthru 286, Personal Computer Support Group, 11035 refers to one of the many names OS/2 was called before it was Harry Hines Blvd., Suite 206, Dallas, TX 75229, (214) 351-0564. officially released.) CIRCLE 32 ON FREE INFORMATION CARD The basic MotherCard contains a battery -backed clock/calendar, an 80287 socket, and one megabyte of memory; on optional 286 Rainbow Plus, PC Technologies, Inc., 704 Airport Blvd., daughterboard will accept as much as four megabytes, built on PO. Box 2090, Ann Arbor; MI, 48106, (313) 996-9690. CIRCLE 33 ON FREE INFORMATION CARD special modules. However; if you use the daughtercard, you won't be able to install a full-length card in the adjacent slot. The rear MotherCard 5.0, State of the Art Technology Inc., 657 N. mounting bracket has a reset switch; changing from 8088 to 80286 Pastoria Ave., Sunnyvale, CA 94086, (800) 237-1713, (408) mode is done via software programs and causes a reboot. Reboot- 245-3366 (CA). CIRCLE 34 ON FREE INFORMATION CARD

MultiSync monitor (used for EGA compatibility testing), NEC Home Electronics, Computer Products Division, 1255 Michael Drive, Wood Dale, IL 60191, (800) NEC -SOFT. CIRCLE 35 ON FREE INFORMATION CARD

Pencept Penpad 320, Pencept, Inc., 39 Green Street, Waltham, MA 02154, (617) 893-6390. CIRCLE 36 ON FREE INFORMATION CARD

Limbo II, Apparat, Inc., 6801 South Dayton, Englewood, CO 80112, (303) 799-0818. CIRCLE 37 ON FREE INFORMATION CARD FIG. 12-SOTA's MotherCard 5.0 ing normally forces operation in 286 mode, but pressing F10 will 286 Rainbow Plus initiate 8088 mode. Utility software is included. PC Technologies markets a number of accelerator boards with The MotherCard is extremely fast-with a 12 -MHz 80287, the various options. The Rainbow Plus (shown in Fig. 11) includes a 10 - board approaches 386 speed in CAD applications. In addition, MHz 80286, a clock/calendar, a multi -mode EGA adapter; and an unlike many boards, the MotherCard is compatible with EGA, LAN 80287 socket. In addition, an optional daughtercard provides a programs, and other "problematic" applications. parallel interface and a Microsoft Inport mouse interface (like the Mach 10). Recommendations As with the Tiny Turbo, the host 8088 is removed and re -installed We examined a number of octopus boards; the Nickel Express is on a small daughterboard. A 40 -conductor cable connects the the only one that worked and the only one whose documentation assembly to the host PC. The rear connector provides speed- and was comprehensible. However; we don't like the idea of loose monitor -select toggle switches, a 9 -pin monitor connector; and wires hanging off a PC board, so in the under -$150 price range, access to the configuration DIP switch. The DIP switch selects we'd really recommend upgrading to a turbo motherboard- monitor type, and allows you to set up for a dual -monitor system. It unless you're working with an IBM PC (not a clone) and wish to also enables the CGA and Hercules emulations (which are turned retain use of the BIOS and BASIC ROM's. on and off via software). Others switches control cache state at In the $400-$800 price range, the choice becomes much tough- power up and indicate host memory size. Toggling the speed - er; especially because many products are often heavily discounted, selection switch causes a reboot. so comparing list prices may not be appropriate. For example, we The board provides a moderate speed increase, and we de- recently saw both the Tiny Turbo and the Mach 10 (bundled with tected no problems with the EGA adapter. However; in Hercules mouse and Windows) being sold for about $350. The Tiny Turbo mode, the graphics screen (under AutoCAD 2.6) was simply un- has the performance advantage, and it's a half-length card, but watchable due to vertical rolling. With the optional parallel and buying a mouse and a copy of Windows could easily cost you more mouse ports, the board could be useful in a situation where slot continued on page 106

100 BUILD THE PT -68K

This month we build test. reset. and clock circuits.

11111111111111411111I1 Ilf111111 111111111111111111111101.111111

PETER STARK, I 10.114 Milt \ 5 STARK SOFTWARE SYSTEMS CORPORATION 1 0 t SI SS i

ast month we described the PT -68K computer's hardware and is low when it is asserted and high when it is negated. (Some books oftware n general terms, covered the data and address buses, call that negative logic.) In a typical computer, both kinds of circuits and discussed how to get started. We are now ready to begin may be used, and often are. In fact, an active -high circuit may be construction. located a tenth of an inch from an active -low circuit. Although this month's installment presents the parts layout di- In text and in schematics, active -low signals are marked with a agram for the entire printed circuit board, please don't blindly start bar over the signal name: I-IALT, for example. By contrast, a signal stuffing parts in a big rush to get things finished. Instead, follow the without the har, such as rco or Ala, is active high. sequence presented here. We are going to build the PT -68K in sections, providing detailed explanations of what each section Step 1: get ready does and why In the process, we will also test each section by ./.s- shown in 2 last time, start by mounting the PC board performing one or more simple exoeriments. There are two reasons and the power supply on a wooden board that measures about for following that procedure: First, it gives us the chance to learn 12" x 24". Then hammer two brads through the appropriate how the system really works. But, equally important, it will give us a board holes, as shown in :hat photo. Use the holes mentioned chance to test each section and isolate small errors before they to avoid short circuitirg the power supply become big problems. Note, in Fig. 1, how the board is oriented: The power connector is right next to the power supply, and the. six expansion Some theory connectors are in the left rear corner We wil use the words left, Digital circuits represent the binary digits 0 and 1 by means of right, front, and back :o describe the board when itis posi- voltages; in most microcomputers, the two voltages are often tioned like that; it will fit into a "baby" PC AT clone cabinet in the called low(which is a voltage between zero and roughly 0.8 volts) same orientation. and high (which is a voltage between about two and five volts). Note also that the wiz with all of the white lettering, called There are exceptions, of course-such as in an RS -232 circuit, the silk-screen layer; is called the top, and the other side of the which might connect a computer and a printer together, where board is called the bottom. All soldering will be done on the larger positive (and negative) voltages are used. However, the bottom side; there are no solder joints whatsoever on the top or specified ranges are the most common. In any case, the range silk-screen side. between 0.8 volts and 2.0 volts is a "no -man's land," if a digital signal is in that range it usually indicates a problem. Step 2: learn to solder Many people think that a low voltage is a 0, and a high voltage is a If you already have experience soldering components to a 1, but that is not always true-in fact it could be the other way delicate printed -circuit board, you may skip to step 3; other- around. So talking about ones and zeroes can be ambiguous, but wise get some advice from a professional on proper soldering talking about lows and highs is always specific. Note that we don't technique. really care about the exact value of a signal's voltage, so long as it Note that both sides cf :he board seem to be covered with a falls into one of the specified ranges. thin layer of green paint; that layer is called a solder mask. The However, there's yet another way to talk about digital signals: We entire sflace area of each side of the board is masked except can say that a particular signal is on or off. Another way of express- for the area surrounding each hole; the purpose of the solder ing that is to say that a signal is asserted (on) or negated (off). mask is to keep the solder on a pad from spreading to adjacent The problem is that some circuits use a high to assert a signal, and pads or traces. other circuits use a low to assert a signal. So that gives us two types You can see the copper traces through the solder mask, and of circuits: active -high and active -low An active -high circuit is high you can see that the traces on top of the board go mostly left - when it is asserted and low when it is negated; an active -low circuit right, whereas the ores on the bottom go front -back.If a

101 J1 IC81IC80 a IC68IC67 4t3 IC54IC53 IC39IC38 C15 J16= J151=1 -R24_R15__R14_ R16 IC32 J18 I IC23 I IC14IC13 C491 IC82 IC69 IC55 IC40 d17 1=3J17 J18 -R25 IC24 Ei C10 C(9 I IC15 J2 co I IC83 IC71IC70 rc4rc) IC56 IC41 d18 I IC25 IC16 J3 C52 IC85IC84 (7.)1 IC72 IC58IC57 IC43IC42 C20 C69 I IC17 17 ci3I IC86 3 I IC73 cc.$ IC59 IC44 C21 01 IC26 I IC18 J4 C 4 IC87R18 IC74 R17 J23IC60 IC61 IC45 J19 IC19 J5 IC88 01 IC75 I IC62 IC46 IC27 IC20 J6 R26 IC47 -C48 IC28 J20 IC21 J8 ICI 4 R19 4 C66 aIC9 IC2 C2 nLI I IC89 C7.01 IC63 1 1 IC33 -1310--R9- C4 J25 IC90 4C I 60 I 4 IC76 58 1 IC64 I IC49IC48 4 I IC34 4C13 IC29 I CIC IC4 C-)C.1 1 [ IC30 R211 1R20 C591 Ic77 1 IC65 C71 \Itj C671 icci3,2 1 IC50 1 IC35 -R12 1C22 I CII 1 IC6 CT) CD CC 1 IC78 C72 I IC51 4 1 IC36 I FM FM R3 R4 co UIM 1F, 9J24 IC66 C141 : IC37 R13 , IC31 R5 R6 IC12 I C7 IC5 C51 IC79 I -057- I IC52 I J13 FLOPPY RI - -C6 -R2 s,ji 1 C6514. SOINOLI10313-01CIVEI csi connection has to go from one corner of the board to a diagonally opposite corner, it may travel in one direction on the top, then go through a hole to the bottom, and continue at a right angle there. In some cases, a particular connection may go back and forth, top to bottom, several times before it arrives at its destination. The hole that connects a trace on the top to a trace on the bottom is called a via or a feedthrough, and it is plated with copper internally; hence it does not need to be soldered on both sides of the board. Solder only those joints into which you insert a lead. And don't wash the board prior to soldering.

Step 3: the power connectors The power connector actually consists of two six -pin connectors, J10 -a and J10 -b, in the right rear corner of the board. They are shown in Fig 2, where J10 -a is on the left, and J10 -t) is on the right Read the following paragraphs before you do anything. The power connectors are a potential source of big problems. Note that the two board -mounted connectors are identi- FIG. 2-POWER CONNECTOR J10A (left) and J10B (right). Also cal, and the two power -supply plugs are probably identical as shown are the matching plugs from the power supply. Notice how the tabs on the plugs matci the bridges that have been removed well. In other words, it is extremely easy to make a mistake and from the board -mounted connectors. plug the wrong power supply plug into the wrong connector on the board and burn up the works. We must make sure that flowing through the device, which is controlled by one section never happens. of IC32, a 7406 open -collector hex inverter. First, look at the two board -mounted power -supply con- Note that IC32-b, IC32-c, IC32-d, and IC32-f are all part of one nectors. One has six pins, the other, only five-the next -to -the - integrated circuit, IC32. It has six inverters; the other two are last pin is missing. To help remind you of which goes where, cut used elsewhere. For now ignore the fact that IC32-f has a small off the next -to -the -last board -mounted pin on J10 -b, as shown circle, called a bubble, on its input, instead of its output; that in Fig. 2. notation will be explained next time. Next, compare the shells of those connectors with the con- Before connecting them in their final form, we want to use the nectors supplied in your kit. In the plastic, behind each of the LED's for experimenting and debugging, so we'll solder the metal pins, is a small rectangular opening with a tiny plastic LED's directly to the PC board for the time being. Referring to Fig. "bridge" above it. 1, install R14 and R15 (330 ohms), R16 (220 ohms), R24 (2200 Now look at the two matching plugs from the power supply; ohms), C11(0.1 RF), and the 14 -pin socket for IC32. While you're six small plastic tabs protrude from the long side of each. When at it, also install R25 (33 ohms), and J18, the 4 -pin header strip for the plugs and sockets are brand new, the tabs on the plugs the speaker. Do not install IC32 in its socket yet, and don't bother prevent them from being inserted into the sockets because the connecting the speaker to J18. long tabs hit the bridges. The object is to cut just the right Then install the three LED's at J15, J16, and J17. The cathode combination of tabs and bridges so that the six -wire plug only lead of each LED, usually marked by a flat edge on one side, fits J10 -a, and the five -wire plug only fits J10 -b. If you look should go toward the resistors. If at all possible, check each LED closely at Fig. 2, you will see how we accomplished it. first, because sometimes LED's are made with the flat on the Now that you know what must be done, solder the two wrong side, but rather than destroy those LED's, manufacturers connectors to the board, and then match up the bridges and sell them at low prices on the surplus market. the tabs so that the power supply plugs in only one way. Make Install each LED so that it stands up straight, about 1/2 inch sure that the connectors are oriented correctly. above the board. Later, when we're ready to mount the board in While working on this section of the board, also install C65 (10 the cabinet, we'll cut each LED lead just below the LED itself and IA tantalum). Make sure itis oriented correctly, because tan- use the stubs as connectors for the panel -mounted LED's. talum capacitors have a nasty habit of exploding if connected Now connect the power supply cables to J10 -a arid J10 -b backward! Then install C3, C4, and C5, three 47-pF disc ceramic and power up the board. The power indicated LED (at J15) capacitors. They look much like the many 0.11.15 capacitors; should light, though it may immediately go off again. If so, don't mounting them now avoids possible confusion later. Also be alarmed-most PC -type power supplies shut themselves off mount C6 (0.1 RF) now. if there is insufficient load, and a single LED is a very small load Besides C63 (1 µF) all the remaining capacitors are 0.11.11 disc indeed. If that's the case, turn off the supply and temporarily ceramics. Digital circuits are notoriously "noisy" and computer connect a 150- or 330-ohrn resistor between pins 7 and 14 of the designers have learned the hard way that it is necessary to install IC32 socket Don't force the leads all the way into the small bypass capacitors between the + 5 -volt line and ground socket; rather, hold them gently aginst the appropriate at many points on a PC board to keep that noise off the dower pins. Then try again. lines. A general rule of thumb is that one such capacitor should it the LED does not light at all, even for an instant, then most be installed for every two or three digital IC's. likely either the LED s in backward, R14 is the wrong value, or the NOTE: Some IBM -type power supplies can be damaged if power supply is defective or not properly connected to J10 -a operated without a load, so never do so. and J10 -b. Correct the problem before continuing.

Step 4: LED indicators Important note Most "baby" AT cabinets have two or three status -indicator During construction, often we will solder some connections, LED's on the front panel. Eventually we'll connect those LED's to turn on the power, try the new configuration, turn off the power, J15, J16, and J17 on the board to indicate power on, hard -disk make more connections, and so on It is absolutely essential activity, and microprocessor halt status, according to the circuits that you turn off the power before doing any more wiring, shown in Fig. 3 (which aiso shows speaker wiring.) In each case, soldering, or inserting IC's into sockets. Better yet, turn off a resistor in series with the LED (or speaker) limits current the supply and also unplug it.If you forget to turn off the power,

103 known state-when the system is first turned on. The process is LED LED1 +5V called resetting, and is done by temporarily grounding two 6 PROBE DISK (FOR 68000 pins: RESET and HALT. Remember that they are active -low TESTING) signals, so grounding them asserts them. The pins must be -48+- grounded simultaneously for a minimum of 100 milliseconds. R16 The 68000 must be reset automatically every time power is 220f2 turned on. It's also useful to be able to reset the microprocessor JAA manually, by pressing a switch, when the computer does some-

FROM J14 J16 thing it is not supposed to do. Both functions are accomplished 1C16,PIN15 with the circuit shown in Fig. 4. (WINCHESTER A 7406 LED2 The important device in that circuit is IC91, a 555 timer, which CIRCUIT) + 5V HALT is connected to a timing circuit consisting of R23 and C63. When the computer is running, C63 is charged through R23 to about R24 t + 5 volts, and the output (on pin 3) is low; IC22-c, IC22-d, and 2.2K ?. R15 IC66-e invert the 555's signal to provide the desired active -low 3300 13 8 signals. The two 2200 -ohm resistors (R20 and R21) are tied to cr-a VK +5 volts; they're called pull-ups because they pull the lines FROM associated with them up to the supply voltage. IC47,PIN17 J17 (68000) IC32f IC32d Getting back to the reset circuit, whenever the terminals of A 7406 Y6 7406 LED3 J23 are shorted, the trigger input of the timer goes low, which POWER causes the timer to ground pin 7, which discharges C63. (When power is first applied C63 starts off discharged). The 555 timer -34- sees that low voltage and outputs a high on pin 3. That signal is R14 inverted by IC22-c and IC22-d, which then assert the and 33011 HALT lines of the 68000, thereby resetting it. (The reset signal also

goes elsewhere through IC66-e, but more on that later) When the short is removed (or the power -supply voltage has J15 risen), C63 starts to charge through R23. The 555 monitors that rising voltage, and when it reaches about 66% of the supply voltage (3.3 volts in our case), shuts off the output on pin 3. That negates the andi-uLT lines and lets the 68000 begin opera-

SPKR1 tion. FROM IC321a 811 How long does it take for the voltage on C63 to reach 3.3 1C10,P1N13 A 7406 volts? Approximately one time constant, which is defined as the IDUARTI R25 product of R23 and C63. Since R23 is 1 megohm (1 x 106) and 3311 C63 is 1µF (1 x 10-6), the product is (1 x 106 x 10-6) = 1 second. Thus the RESET and HALT signals will go low for about 1 J18 second at startup or whenever J23 is shorted. Later we'll connect a pushbutton switch to J23 to provide a manual reset FIG. 3-LED AND SPEAKER CIRCUIT. Each device is driven by function. an open -collector inverter. Now that we know how the circuit works, let's build it. Install you may well burn out some or all of the components on the the parts listed below, noting the polarization of tantalum ca- board, and perhaps burn a few of the PC -board traces as well. pacitor C63. (Its positive terminal must go toward pin 6 of IC91.) So now turn off the power and connect a thin wire, 12-15" Also, the two -pin header strip, J23, has a short end and a long long, to terminal 1 (on the left) of J14. Try to use a thin solid wire, end; the short end goes through the board and is soldered on about 30 gauge. If you use stranded wire, twist the strands of the the bottom. Now install these parts: R22 and R23 (1 megohm); loose end and tin it. Next, insert a 7406 IC into IC32's socket. R20 and R21(2200 ohms); C57, Cal, C62, and C64 (0.1 µF); C63 (1 Note that all IC's on the entire board are oriented the same way: µF); sockets for IC91 (8 pins), IC22 and IC66 (14 pins), and the pin 1 (marked by a dimple or a notch, both on the IC and also on two -pin header strip at J23. the silk screen layer on the board) goes toward the back. Then Also install the two 0.1 pl capacitors to the left of IC66. Then turn the power back on. install a 555 in the IC91 socket, a 7406 in IC22, and a 74LSO4 in The wire connected to J14-1 (shorthand for terminal 1 of J14) IC66, and turn on the power. The LED should go on for is now a test probe, which we will call the LED probe. If you about a second, and then go off. ground its loose end (to pin 7 of IC32, for example), the LED at Now use the LED probe to check the signals at the outputs of J16 should go off; if you connect it to a high voltage (pin 14 of IC22-c, IC22-d, and IC66-e. Connect the probe to IC22-c and IC32, for instance), it should go on. In addition, when the probe use a screwdriver or wire to short the two pins of J23; the test is not connected, the LED will also be on. Furthermore, when LED should go off and then, a second later, back on, indicating connected to a source of pulses, the LED will light, but its that the signal went low and then high. If all is well, check the brightness will depend on the type of pulses. For example, a outputs of the other two inverters. Otherwise track down the pulse stream that is high most of the time will be brighter than source of trouble before continuing. one that's mostly low But connecting the probe to any pulse stream will produce a slightly dimmer light; that's an easy way to Step 6: The clock circuit recognize a pulse signal. The PT-68k's clock circuit is shown in Fig. 5. IC78 is a 16 -MHz Now we've got a simple logic probe for checking out other oscillator module that contains a crystal oscillator and all logic parts of the computer. If you have a meter, an oscilloscope, or a necessary to provide a TTL-level squarewave output. The os- "real" logic probe, feel free to use it instead. However, it may be cillator's output goes to IC77-a, half of a 74ALS74 D flip-flop that more convenient to use the built-in probe. divides the frequency of the clock signal by two. The 8 -MHz output, called cLe, is used in a number of places throughout the Step 5: the reset circuit computer; a separate clock signal drives the 68000. The 68000 microprocessor must be initialized-placed in a Jumper J24 selects the frequency at which the microprocessor

104 +5V +5V +5V

R22 SR23 1MEG 4 8 1MEG RST V DISCH

M C63 + 5V 1µF IC91555 6 16V TRIG THR R21 2.2K RESET 9 OUT TO IC47, PIN18 (680001 GND FILT + 5V

1 5 R20 2.2K O HALT TO 5 TO IC47, PIN17 RESET J23 C62 ; C64 (680001 BUTTON 1 O 1

MAP 11 TO IC90, PIN9

FIG. 4-RESET CIRCUIT. The 555 generates a high -going one - second pulse each time the terminals of J23 are shorted. The runs. That signal is krown as MPUCLK. In the position shown, IC77-b inverters (IC22-c, IC22-d, and IC66-e) drive the appropriate lines divides the 16 -MHz signal by two, to provide an 8 -MHz clock. low. However, by adding optianal oscillator module IC79, a different frequency may be chosen by moving the jumper to the other position. For example, to run the computer at 10 MHz, you would 5V IC77a alternate position. CLK8would still be 8 MHz, but MPUCLK would now t14 74ALS74 be 10 MHz. Two modules are necessary because CLK8 is used elsewhere in CLK 8 the computer and must stay at 8 MHz even if the 68000 itself runs IC78 faster However, do not try to increase clock frequency at this time; 16 -MHz depending on the frequency chosen, some components may have OSCILLATOR to be altered. We'll discuss the details in a future installment. Now mount the 16 -MHz oscillator module (IC78) by soldering it CLK directly to the boars, without a socket. Note that three corners are rounded; the pointed corner identifies pin 1, which should be closest to IC65. Then install a socket for IC77, a 3 -pin header at J24, and three 0.1 µF capacitors (C58, C59, and C60). Then insert a IC77b 74ALS74 (note: ALS, not LS) into the IC77 socket, and a shorting 1/2 74ALS74 jumper from the center pin to pin 1 of J24. MPUCLK 12 Next, power up the computer If you have an oscilloscope or a ITO 68000 logic probe that can detect pulses, examine CLK8 and mPuctk for the IC47,PIN15) 8 -MHz clock signals. (An inexpensive oscilloscope may have trouble displaying the clock signal, or may show it as a very distorted 5V sine wave.) To use the built-in LED probe, first note how bright the LED is 11 -L CLK when the probe wire is not connected to anything. Then connect it I to CLK8 The LED is flashing on and off so fast you cannot see it, so it should be dim, indicating that the signal is high part of the time and low part of the time. Ivt 1124 I IC79 ; Next, connect the LED probe to MPUCLK and note its brightness. I (OPTIONAL) I Then s ip the shorting jumper from J24 and note whether the LED I I gets brighter or darker. Each time you remove the jumper, you stop IC77-b from counting. Sometimes it will stop in the set state, in I I a__ which case the LED will be getting a full high voltage and become brighter; other times it will stop in the reset state, in which case the LED will go off. Try removing and installing the jumper several times; FIG. 5-CLOCK CIRCUIT. IC78 generates a 16 -MHz signal that if you see the LED in ooth states, the clock circuit is most likely fully IC77-a divides by two to provide the main clock signal. IC77-b functional. generates a separate clock signal for the microprocessor, there- That's all we have time for now; next time we'll install the micro- by allowing it to run at another (faster) rate. processor itself and start learning about how it works

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plain -vanilla XT coes not crash with the same combination. TURBOCHARGE YOUR PC We refrained from naming names in those examples because we continued from page 100 can't blame the manufacturers involved; they simply can't be expected to test every combination of hardware and software. than $200, even at discounted prices. And the Mach 10s method o The message 'or the buyer is not a new one: beware when speed switching is more convenient. The overall price/perfor buying, and be extremely careful when installing and initially using mance leader is PCSG's Breakthru 286. any type of accelerator Back up your hard disk, rename your Above $800, Orchid's PCturbo 286e is hard to beat. The 8 -MHz AUTOEXEC.BAT and CONFIG.SYS files, and then install your new model we examined is faster than the 12 -MHz Breakthru 286; the 10 - hardware. Only after getting it to work should you add software MHz model should be a real screamer However, the 286e won't run drivers to your CONFIG.SYS file, and do so one by one, rebooting a third -party EGA, so SOTA's MotherCard is a strong contender, and testing after adding each one. Then do the same with any especially if it turns out that the board can run OS/2. memory -resident programs loaded via AUTOEXEC.BAT. Expect that there will be problems and take a step-by-step approach to solving Conclusions them. If a board works by itself, but not with a particular software All of the accelerator boards we tested for this article enhance driver, try changing the order in which things are loaded. performance. At the same time, every single one exhibited some Later on, when you add a new software driver or memory - problem with compatibility or performance. For example, one resident program, and your machine crashes, remember that the PC board simply wouldn't run AutoCAD 2.6. Replacing a PLD allowed and the XT were designed to work in a very specific environment, the program to run, but prevented use of EMS memory A complete and that you have drastically altered that environment in a way in board re -design was necessary to solve the problem. Another which the original designers could not possibly have foreseen --so board crashed under some combinations of resident and non- don't curse them. If you really need the speed, go out and buy a resident programs -but then so does a plain -vanilla XT. However, a faster machineCD11

106 L

Tired of pushing buttons and remembering codes? Here's a lock that's opened by an electronic key. Electronic Combination Lock

PAUL RENTON

ELECTRONIC -LOCK CIRCUITS HAVE BEEN Many combinations possible codes. But while the MCI45028 around, in various forms, for many years. When encoding data. IC2 can read one decoder can read three states on address Most have a keypad on which the user of three states on each of its address pins: pins A1-8, it can only read a high or a low enters a combination of numbers. If the I) open with no connection; 2) low-con- signal on its A9 pin, thereby allowing combination matches the one that's pro- nected to ground; 3) high-connected to only 2 x 38 (13,122) possible addresses. grammed into the lock, the lock opens. the positive supply voltage. Since the IC a range thatisstilllarger than that Unfortunately, it takes a relatively large reads each as a distinctly different state, provided by a 4 -digit keypad code.It amount of digital circuitry to decode and the encoder operates on a "trinary" (three gives reasonable assurance that if some- match keypad entries against the pro- value) system. As there are nine address one did build an electronic key. they grammed combination. pins, the encoder can encode 39 (19.683) would have a difficult time unlocking the On the other hand, the electronic -lock system shown in Figs.I and 2 uses only Q1 three integrated circuits: ICI, an 2N2222 Li-O MCI45028 that is part of the lock itself R3 5V 22011 RY1 (Fig. 1), IC2. an MCI45026 that functions AAA as an electronic key (Fig. 2), and IC3, a 5 - volt regulator. That all -electronic approach allows the electronic lock to oc- 161' 11 cupy only a couple of square inches of VT 5V Al 0 space, while the key is small enough to be DATA A2 carried in a pocket. Although anyone with 0 2 access to the key can unlock the lock, A3 4 which is not true for a keypad lock, the A4-0 ICI SEE TEXT low cost and simplicity of the keyed elec- 145028 A5 0 FOR CONNECTIONS tronic lock makes it somewhat more con- 15 A6-0 venient to build. 14 The MC145026 is usually used to en- A7 13 code commands for radio -frequency, ul- At 12 trasonic, and infrared remote -controllers. A9 It has nine address pins. When instructed to send a command, the IC reads the pins. 10 encodes them into a series of bits, and then sends the information out serially. Cl R2 C2 The receiver, an MCI45028, receives the 0033 100K 0082 serial transmission and checks the received address data against the program- I ming of its own nine address pins. If the programming is an exact match then pin II. the VT (Valid Transmission) line, goes FIG. 1-THE ELECTRONIC LOCK is actually a decoder (IC2) that compares the wiring of its address high. pins with that of the key.

107 PARTS LIST All resistors% watt, 5%. R1, R4-10,000 ohms R2-100,000 ohms SEE TEXT R3-220 ohms FOR R5-22,000 ohms CONNECTIONS Capacitors C1-.0033 p.F, ceramic disc C2-.0082 p.F, ceramic disc C3-.001 RP ceramic disc Semiconductors IC1-MC145028 decoder (Motorola) IC2-MC14026 encoder (Motorola) IC3-7805 5 -volt regulator Q1 -2N2222 NPN transistor Other components B1 -9 -volt battery J1-DB-25 socket FIG. 2-THE ENCODING IC IN THE KEY. IC2. outputs a series of long and short pulses that represeit P1-DB-25 plug the wiring of address pins Al -A9. The pins can be brought low. or high. or left open. RY1-5-volt DC relay S1-SPST switch electronic lock without knowing the prop- RY I. The VT pin remains high, and the Miscellaneous: Perforated wiring or con- er combination. relay thereby remains powered until the struction board, terminal strip, battery The encoded data sent from IC2 con- decoder no longer receives a properly en- clip, wire, solder, etc. sists of a series of long, short, or a com- coded sequence of pulses. bination of long and short pulses that represent the state of the address pins. A Construction low signal on an address pin is encoded as 'I'hc timing of the pulses is not so crit- a sequence of two consecutive short ical that only high tolerance parts must he To set the combination, the encoder's pulses, a high signal is encoded as two used; 5% resistors are acceptable for both address pins are connected to ground, the consecutive long pulses. An open pin is the encoder and decoder, which contrib- 5 -volt power supply (pin 16), or left open. encoded as a sequence of a long pulse utes to the low cost of the electronic lock. One way to program the address pins followed by a short pulse. After the en- The decoder (Fig. I) is powered by a 9 - would be to use a set of switches to place coder sends out its sequence of encoding volt transistor -radio type battery and can each pin at to one of the three states. pulses it immediately re -transmits the se- be built on a small piece of perforated However, to keep the key pocket size, the quence for added reliability. (The pro- wiring or construction board. Nothing is pins are soldered directly to ground, to 5 cedure is called redundant transmission. critical and any layout can be used. To volts, or simply left with no connection. It is commonly used to insure the received simplify connections to external equip- Soldered pins allow the key to be made integrity of transmitted data.) ment. such as a an electric door release, small enough to fit inside a conventional Decoder ICI uses the pulses it receives relay RYI's contacts should be brought DB-25-type connector, although the sol- from the encoder to determine the state of out to a dual screw -type terminal strip. The dered -pin programming cannot be easily the encoder's address pins. While receiv- decoder's combination should be wired changed to a new code. ing the data, it compares the state of the after the encoder key is completed. If you only expect to set the combina- encoder's address pins against the state of The encoder key (Fig. 2), does not have tion once, then it would be appropriate to its own address pins. If there is a perfect its own power source because it obtains simply wire two or more address pins of match on all pins the decoder brings its VT power from the decoder when itis the encoder and decoder to the positive pin high to indicate that the proper address plugged in; hence, the key consists of supply and/or ground to generate the sys- was received. By going high, the VT pin only IC2, resistors R4 and R5, and capac- tem's combination. If you anticipate hav- turns on transistor QI, which powers relay itor C3. ing to change the combination, then you might want to consider putting switches on the address pins of the lock and key so that the addresses could be easily changed. But as stated earlier, doing so would mean the key would be larger. A compromise is to use switches on the decoder's address pins and take the time to rewire the key if you change the combination. To make the electronic key, locate a connector that will hold IC2 along with the two resistors and the capacitor. For- tunately, the commonly -available DB-25- type connector shell has just enough space for those components, but feel free to use whatever case or connector meets your needs. Regardless of the kind of connector used as the key, it must have at least three terminals available for connection to FIG. 3-THE ENCODING ASSEMBLY can be built small enough to fit within the hood of a DB-25 the lock: one for power, one for data, and connector. Alternately. you can use any kind of connector large enough to house the circuit. continued on page 129

108 J Understanding Data Sheets of RF Power MOTOROLA Semiconductors MRF646

Transistors The RF Line Data sheet parameters are 45 W - 470 Mlle CONTROLLED 0 NPN SILICON RF POWER TRANSISTOR RP POWER what tell you whether TRANSISTOR NPN SILICON dr,vett 10, 12 5 VII UHF wo.,7141 arrspe.Lee apohcot,on, .n an RF power transistor nd.sthai and conunecc M or, pment owat.ng to 5'2 MMI 50m...I 125 Von 470 MM, Characte,s, OutPut Power 15 Watts can do the job. kfinmorrt Gain lS dB Eflpoency 54% Characteoted wail Set fe Ecto,aient Lan,. Slnal Irnadance Parametes NORMAN E. DYE. Elioit In hiatc.ng Network to, E1coadO,.01.1.0. 100% Tested tot Load Mnrnatcn Sttess at all Phase Angles senn Motorola Semiconductor Products 20 1 VSWR 6, 16 von Mir Lne and 50% Overdrite

DATA SHEETS 01 -TEN ARE THE SOLE o source of information about the capabilities and characteristics of a product. That is particularly true of RF power transistors that are used throughout the world, so it's important that the user and the manufacturer of a product speak a com- MAXIMUM RATINGS I Roo, Syr... PO.. u.1,Coageta, mon language; i.e., what the semicon- Cromer Va VCEC , Vo< Cawley sew Pam. PCIIC 34 Vac ductor manufacturer says about a Emma, Soo VO4tfap Vat VEIIC .,. 51, CoOsaa C - Connutx.1 .0 at mo. transistor is understood fully by the cir- - M. 110 socoat mow 10 [01..104. 111111,m T.. Dlr.. 0.tan Tc 25°C O. ,,,,, IASI cuit designer. Ottram CoOr 25.0 Ve.0 ,LFLE .20L4,12 In this article we will review RF-power- Swage 2 .. e,, ,, -65 o`-700 't THERMAL CHARACTERISTICS transistor parameters from maximum rat- Chweetstathe 1Pathleto VS.* lane ings to functional characteristics. We'll TM,,...' Rwillne lunct.on .0 CM .04C I 4 °VW cover critical specifications. and how values are determined and what they signify. '111E4 f*T7rIr Finally, we'll cover possible tradeoffs in 2111;TiSir device specifications and their importance 11r -o -a val to the circuit -design engineer. C5I But before we get into the subject, let's take time out for a brief explanation of the terms die, bond pads, and top metal, because, although those terms are used when describing RF-power-transistor pa- and functional. By definition, the DC ased junction. The specifications are con- rameters, they may be unfamiliar to many specifications consist of breakdown volt- ventional and are generally standard of you. ages, leakage currents, hFE, or beta (DC throughout the semiconductor industry. Although we consider an RF power gain), and inter -element capacitances. Leakage currents (defined as reverse - transistor to be a "unit" device that visu- The functional specifications cover AC biased junction currents that occur prior ally resembles a transistor, it is, in fact, an parameters: gain, ruggedness, noise fig- to avalanche breakdown) are likely to be integrated circuit that consists of several ure, and input and output impedance. more varied in their specification and also hundred to more than a thousand individ- Thermal characteristics do not fall cleanly more informative. Leakage currents are a ual parallel -connected transistors on a into either category since thermal resis- result of material defects: mask imperfec- single silicon chip. In this instance, the tance and power dissipation can be either tions and/or undesired impurities that en- chip, with allits integral transistors, is DC or AC. so we will treat thermal resis- ter during wafer processing. Some called a die. The bond pads are the con- tance as a special specification and give it sources of leakage currents are potential nections for the both the main emitter, its own heading of thermal charac- reliability problems, most are not. Leak- base, and collector leads, and the individ- teristics. FigureI shows how DC and age currents that are material related, such ual transistors. The term top metal refers functional specifications are arranged on as stacking faults and dislocations, or to the deposited metal wires that intercon- a typical data sheet. pipes. created by mask defects and/or pro- nect the individual bond pads. We'll cover Breakdown voltages are largely deter- cessing inadequacies, result in leakage dies and top metal in greater detail later. mined by material resistivity and junction currents that are constant with time and, if depths. Each junction voltage-collector/ initially acceptable for a particular ap- DC specifications base and emitter/base-is generally spec- plication, will remain so. (Since they do Basically, RF. transistors are charac- ified at a current level that is well within not pose long-term reliability problems.) terized by two types of specifications: DC the safe -operating limits of a reverse-bi- Some mnanufacturers do not list leakage

109 ELECTRICAL CHARACTERISTICS ,Tc 25"C unless otheiwise noted ages less than the minimum will not cause Character Ishc I Symbol Mth I Typ Max I Unit ...... -...... - junctions to reach reverse -bias break- Cottestio Entitle, Breakdown Vott.we "CEO t6 Vdc down. with the potentially destructive 1 lc 20 mAdc tri 01 current levels that can result. Collector Emitter Breakdown Voltage 8 VCES 36 Vdc Ilc - 20 rnAdc. VBE 01 On the other hand, a maximum rating Emote, Base Breakdown Voltage a VEBO 4 o Vdc for power dissipation (Pd) is closely ent- IIE 5 0 mAdc. lc r 0/ C011eCtOr Cutoff Current ICES 50 mAdc wined with thermal resistance (0i).In IVCE i15 Vdc. VBE ,0. Ic r 25°C) reality, maximum Pd is a fictitious RACTERISTICS DC Current Gem hFE 40 70 100 number-a kind of figure of merit-be- I lc - 4 0 Adc. VcE 5 0 Vdcl cause itis based on the assumption that DYNAMIC CHARACTERISTICS Output Capacitance Coo 90 125 pF the case temperature is maintained at tics 12 5 Vdc. IE 0.1 1 0 MHz( 25°C. However, providing that everyone FUNCTIONAL TESTS arrives at the value in a similar manner. Common Emmet Ansplitier Powet Gain Urw 4.8 5.4 dB tVcc -12 5 Vdc For.°45 W. tc1MaI58 A& .t 470 Milv the maximum Pd rating is a useful tool Inr Input Power P, 13 15 Watts comparing devices. I VCC 12 5 Vdc. Pp. - 45 W.,470 MHz/ Cottectio Ellicioncv 55 60 % I Vcc 12 5 Vitli.1.0t- 45 W. lc IMakl 58 Ade. I 470 Mtitzt Thermal resistance Load Mismatch Stress . No Degradation on Output Power IVCC 16 Vdc. Po" Note 1.1 470 MHz. VSWR 20 1. The rating begins with a determination All Phase Angles) Series Ertuivetent Input Impedance Zir 1.4 14.0 Ohms of the thermal resistance of the die to its (Vcc 12.5 Vile. P001 45 W. I 470 NSW case. Knowing Bic, and assuming a max- Series Fatuiedlent Output Impedance ZOL.. 1 2 .12.8 Ohms IVcc 12 5 Vdc. P001 = 45 W. I= 470 MH71 imum die temperature, one can easily determine maximum Pd (based on the Roles

1 P.n -15001 Drove Requirement for 45 W output la 12 5 V previously stated case temperature of

. Mismatch stress factorthe electrical otter 00 ettebilehed tO verify the device resistance to load mismatch failure The mismatch 25°C). Measuring Hi, is normally done by stress test is accomplished in the standard test fixture (Figure II terminated in a 20 1 minimum load mismatch at all phase angles monitoring the case temperature (Tv) of Zoi_ Coniumte of the load impedance onto which the device output operates al a given output power, hr. and frequency the device whileit operates at or near FIG. 1-THIS IS JUST A SMALL SAMPLE of the kind of data you'll find in a data sheet. rated output power (1311) in an RF circuit. Simultaneously, the die temperature (Ti) limits placed on hFE. That's because: is measured by an infrared microscope

7 LL a. The specification is unrelated to perfor- (see Fig. 4) that has a spot -size resolution mance as small as I -mil. Normally, several read-

Ldi5 b. Difficulty in control in wafer process- ings are taken over the surface of the die a4 ing and an average value is used to specify Ti. c. Other manufacturing constraints, dic- It is true that temperatures across a die 3 Cob C 2 tated by the device's AC specifications, will typically vary over the range of preclude specific limits for hFE. 10-20°C. Normally, the die uses ballast- 1 Ccb A good rule of thumb for hFE is to set a ing to insure that the heat is dispersed 0 3 6 9 12 15 18 21 24 2730 maximum to minimum ratio of not less more or less evenly across the die's sur- COLLECTOR BASEVOLTAGE (VCBI-VOLTS than 3, with the minimum hFF value se- face. Without ballasting the heat would be FIG. 2-THE OUTPUTAND INPUT JUNCTION lected to assure you of an adequate AC concentrated near the middle of the die. CAPACITANCES canbe read directly from gain margin. Ballasting is a technique that reduces the curves provided in thedata sheet. Output capacitance is an excellent in- emitter current to the transistors in the dicator of relative device size (base area), middle of the die below the emitter current current specifications to allow more waf- provided that the major portion of the out- of the transistors located at the edges of er/dies to pass quality inspection. put capacitance is created by the base - the die. In that way the middle transistors On the other hand, leakage current collector junction and not parasitic capac- dissipate less heat than those at the edges, caused by channels created by mobile im- itance arising from bond pads and other and the heat dissipation is spread more or purities in the oxide (primarily sodium) top metal of the die. Keep in mind that less evenly across the die. A poorly de- tend to change with time and can lead to a junction capacitance will vary with volt- signed die-one with improper ballast- progressive increase in leakage current. age (Fig. 2). while parasitic capacitance is ing --could result in worst -case hot -spot That can render the device useless for a unaffected by voltage variations. Also, in temperatures that vary between 40-50°C. specific application. Distinguishing be- comparing devices, it's important to note Likewise, poor die bonds (see Fig. 5) can tween sources of leakage current can be the voltage at which a given capacitance is result in hot spots. difficult; that is one reason why devices specified. No industry standard exists. By measuring the DC and RF T and designed for military use require HTRB The preferred voltage at Motorola, for in- Ti. along with P and Pin. it's possible to (High Temperature Reverse Bias) and stance, is the transistor's Va. rating; i.e., calculate Hit: from the formula: burn -in testing. Even for commercial ap- 12.5 volts for 12.5 -volt transistors, 28 plications a leakage -current limit should volts for 28 -volt transistors, etc. Ti -Tc ec - be included in any complete device speci- PIN Po fication. Maximum ratings DC parameters such as hFE and Cb Maximum ratings, such as those shown Typical values for an RF power tran- (output capacitance) need little comment. in Fig. 3 for a typical RF power transistor, sistor might be Ti = 130°C; T, = 50°C: (Typically, for RF devices hFF. Instead. tend to be the most frequently misun- Vcc =12.5 Volts:. 1c= 12 amperes; Pin AC gain at the desired operating frequen- derstood group of device specifications. (RF) = 10 watts; P (RF) = 80 watts. Thus: cy is specified). Keep in mind, however. Ratings for maximum junction voltages 130 - 50 80 that DC beta (hFE) is related to AC beta are straightforward and simply reflect the eta= (functional gain). AC beta will usually minimum values set forth in the DC speci- 10+(12.5x12)-80 - 80 - 1°C/W track DC beta, particularly at the lower fications for breakdown voltages. If the Several reasons dictate a conservative RF frequencies. Generally, RF device device in question meets the specified value be placed on (-) First. thermal manufacturers do not like to have tight minimum breakdown voltages, then volt- resistance increases with temperature

110 (and we realize T, = 25°C is not realistic). Maximum collector current

Second, Ti is not a worst -case number. Niaxiniuri collector current II 1 is proba- And third, by using a conservative value bly the most subjective maximum rating on of 0,, a realistic value is determined for RF-transistor data sheets.It can, and is, Ptlimaxr Generally, Motorola's practice is determined in a number of ways-each lead- to publish 0,, numbers approximately ing to different maximum values. Actually, 25% higher than that determined by the three possible current limitations can exist measurements previously described, or in RF transistors. One is package -related, for the case illustrated, a value of one is wire -related, and a third is die -re- = I 25°C/W. lated. Collector current in most older, lower - ic Now a few words about die tem- frequency transistors is wire -and/or pack- perature: Reliability considerations dic- age -limited. which is why those parts gener- tate a safe value for an all Au (gold) ally have 1,.(n,) determined by collector system (die top metal and wire) to be voltage (or by BV, -.E0 for added safety). 200°C. Once Tin00is determined along Higher -voltage parts (such as 28 and 50 with a value for Ojc, maximum Pd is: volts) tend to be wire -limited; when oper- Ti(max) - 25°C ated at lower voltage those components can PD(MAX) safely handle sizable amounts of current. ejc Lower voltage parts (such as 7.5 and 12.5 Specifying maximum Pd for T, = 25°C volts), however, tend to be package -limited; makes it necessary to derate maximum Pd those should have 1, determined by for any value of T, above 25°C. The derat- power -dissipation considerations. ing factor is simply the reciprocal of 01. Most modern, high -frequency transistors

MOTOROLA MRF646 FIG. 4-AN INFRARED MICROSCOPE is used to Semiconductors measure the temperature of various spots on BO. ...-.t.1.AliZotA the die.

IIsi 141

45 W - 470 MHz CONTROLLED 0 NPN SILICON RF POWER TRANSISTOR RF POWER TRANSISTOR NPN SILICON designed for 12 5 Volt UHF large signal amplifier applications in industrial and commercial FM equipment operating to 512 MHz

Specified 12 5 Volt. 470 MHz Characteristics - Output Power = 45 Watts Minimum Gain 4.8 dB Efficiency 55% Characterized with Series Equivalent Large Signal Impedance Parameters Built In Matching Network for Broadband Operation 100% Tested for Load Mismatch Stress at all Phase Angles with 20,1 VSWR @ 16 -Volt High Line and 50% Overdrive. FIG. 5-AN X-RAY PHOTO SHOWS some transistor -cells that are poorly bonded to the die, which will result in hot -spots.

are die -limited because of high current densities that result from their very small current -carrying conductors; those densities can lead to metal migration and premature failure. For those type of transistors, le011ae4 )is determined by using Black's MAXIMUM RATINGS equation for metal migration. That equation Ronne Symbol Volta Unit Collector Emitter Voltage VCEO 16 Vdc calculates a mean -rime -between -failures Collector -Bar Voltage VCBO 36 Vdc (MTBF) based on current density, tem- Emitter -Base Voltage 4.0 Vdc VEBO STYLE I Collector Current - Contsnuout IC 8 0 Adc Pail EMITTER perature, and the type of metal. At - Peak 110 seconds matt 10 7 COLLECTOR I EMITTER Motorola, MTBF is generally set at greater Total Device Dmmetan 0 Tc 25°C Po 175 Watts 4 SASE Carafe AMP* 25°C t 0 Wr.0 E LANGE ISOt AUL/ than 7 years, and maximum die temperature Storage Temperature Flew Tg °C -65 to 0200 %MUNE ER3 NCH is set at 200°C. For plastic -packaged tran- THERMAL CHARACTERISTICS 010 NIB MAO Meg MAO

A 311 25 15 0%0 0 590 Chem. -termite Symbol Una sistors, maximum Ti is set at 150°C and V 17451795 0 490 Osil) Thermal Rectums. Junction to Caw Rex10 .Chi/ C 591t192 0235 0100 ItCnps) is calculated using the resulting cur- O 5% Ter 0 715 Me 5011 537_ MO' 0110 rent density along with a knowledge of the is 0/12 1154 0 170, 010 00i One ,:iT,T.°4-4-T- 0470 0130 die geometry and top -metal thickness.

--b-'Of s31oiso'0iTO It is up to the transistor manufacturer to 110:birS:Wo specify an that is based on the appro- 23111.771' '.4!, 1,11 priate limitation (die, wire, package). Note, cuss ore as however, that the limitation depends to some 123,662191 extent on the application. Circuit designers FIG. 3-MAXIMUM RATINGS AND THERMAL CHARACTERISTICS are also provided by the data sheet. should consult the manufacturer for addi-

111 tional information if 1.,,,, a specific curves. On the other hand, a circuit used and greater -than -normal input drive-all application. to characterize a device is usually narrow - at the same time. Thus, the ultimate test band and tunable, which results in higher for ruggedness is to subject a transistor to Storage temperature gain than attainable in a broadband cir- a test wherein RF Pin is increased up to Storage temperature is another maximum cuit. Unless otherwise stated,it can be 50% above that value necessary to create rating that is frequently not given the atten- assumed that curves such as P cs. fre- the rated P,,; Vcc is increased about 25%, tion it deserves. A -55°C to 200°C range has quency are generated on a point -by -point (from 12.5 volts to 16 volts for mobile more or less become the industry standard. basis by tuning a narrow -band circuit transistors), and then the load -reflection For single, metal, hermetic -packaged de- across a band of frequencies and, thus, coefficient is set at a unity while its phase vices, an upper limit of 200°C creates no represents what can be achieved at a spe- angle is varied through all possible values reliability problems. However, plastic en- cific frequency of interest with proper im- from 0° to 360°. capsulated or epoxy -sealed devices should pedance matching. not be subjected to temperatures above Broadband, fixed -tuned test circuits Testing ruggedness 150°C. are best for testing the functional perfor- Ruggedness tests come in many forms. mance of an RF transistor. Fixed -tuning is Many older devices (and even some newer particularly important in assuring the ones) simply have no ruggedness specifi- manufacturer, and the user of product con- cation. Others are said to be "capable of" sistency; i.e., that the devices made to- withstanding load mismatches. Still morrow will be identical to the devices others are guaranteed to withstand load made today. mismatches of 2:1 VSWR to x:1 VSWR Tunable, narrow -band circuits have led at rated output power. A few truly rugged to the requirement that users and man- transistors are guaranteed to withstand ufacturers use "correlation units" to as- 30:1 VSWR at all phase angles (for all sure product consistency over a period of practical purposes, 30:1 VSWR is the time. Fixed -tuned circuits minimize (if same asc:l VSWR) with both over - not eliminate) the need for correlation, voltage and overdrive. Once again, it is up and that compensates for the increased to the user to match his circuit require- constraints they place on the manufacturer ments against device specifications. of the device. On the other hand, man- Then, as if the whole subject of rugged- ufacturers like tunable test circuits be- ness is not confusing enough, manufac- cause they allow adjustments that can turers "muddy the waters" further by compensate for variations in die fabrica- stating what constitutes passing the rug- tion and/or device assembly. Unfor- gedness test. The words generally say that tunately, gain is normally less in a after the ruggedness test the device under broadband circuit than it is in a narrow - test "shall have no degradation in output band circuit, so transistor manufacturers power." A better phrase would be "no often use narrow -band circuits to improve measurable change in output power." But product specifications for competitive even that is not the best because, unfor- reasons (that is called "specsmanship"), tunately, the device under test can be A good compromise for transistor man- damaged by the ruggedness test and still ufacturers is to use narrow -band circuits have "no degradation in output power." with all tuning adjustments "locked" in As stated earlier, today's RF power tran- place. The moral to all of that is that data - sistors consist of up to 1000 or more small sheet readers should be careful to note the transistors connected in parallel. Emitter test circuit used when comparing specific resistors-ballasts-are placed in series parameters. with groups of those transistors in order to better control power sharing throughout Ruggedness the transistor's die. It is well known by For RF power transistors, the parameter semiconductor manufacturers that a high FIG. 6-AN ACTUAL WORKING TEST CIRCUIT is used to determine the parameters of an RF of ruggedness takes on considerable im- percentage of an RF power transistor's die power transistor. portance. Ruggedness is the transistor's (say up to 25-30%) can be destroyed and ability to withstand extreme mismatch the transistor will still able to deliver its conditions in operation, which causes rated power at its rated gain, at least for Functional characteristics large amounts of output power to be some period of time. If a ruggedness test The functional characteristics of an RF "dumped" back into the transistor, with- destroys a high percentage of transistor - transistor are by necessity tied to a specif- out altering its performance or reliability. cells in an RF power transistor, then it is ic test circuit, such as the one shown in In many circuits, impedances presented likely that a second ruggedness test (by Fig. 6, because without specifying a cir- to a device are variable and unpredictable the manufacturer or by the user while in cuit, parameters like gain, reflected and can abruptly change. In portables, the his circuit) would result in additional power, efficiency-even ruggedness-are antenna may be placed against a metal damage, leading to premature failure of meaningless. Furthermore, most test cir- surface; in mobiles, perhaps the antenna the device. cuits that are used by RF-transistor man- is broken off or inadvertently discon- A more scientific measurement of ufacturers today (even those used to nected from the radio. An RF power tran- "passing" or "failing" a ruggedness test characterize devices) are designed to al- sistor must be able to survive such load is called AV the change in emitter re- low for easy insertion and removal of the mismatches. A realistic possibility for sistance before and after the ruggedness device under test. For mechanical rea- mobile radio transistors (although not a test. V is determined largely by the net sons, that sometimes limits device perfor- normal situation) is the condition where- value of emitter resistance in the transistor mance, which explains why the perfor- by the RF power device "sees" a worst - die. Thus if cells are destroyed, emitter mance attained by users frequently case load mismatch (an open circuit, any resistance will change with a resultant exceeds that indicated in data -sheet phase angle), along with maximum Vcc, continued on page 126

112 L 3C°

POOR STORAGE DUKE BERNARD

With nothing more than an oscilloscope. a video camera. and a VCR. hobbyists can have many of the advantages of fancy logic analyzers and digital storage scopes.

WHEN A NEWLY DESIGNED PIECE OF ELL(- for powerful logic analyzers that can be black -and -white surveillance camera will tronics equipment or an existing piece of triggered by the fault condition and then do fine. However, if an expensive color equipment that has gone bad is being de- recall the signals that preceded the error. camera is used, to prevent burning the bugged, it's common practice to trace sig- Unfortunately, the hobbyist and the small- image tube care should be taken not to nal paths by using an oscilloscope. With business electronics professional gener- leave the camera pointed at a very bright digital equipment, logic analyzers are ally cannot afford the tens of thousands of trace on the scope for long periods of often used to check timing and even store dollars that such equipment costs. time. That is less of a concern if the cam- the waveforms on floppy disk for future With a little ingenuity, however, com- era uses a solid-state imager. evaluation. Such equipment is very con- mercially available video equipment can venient to use, but very expensive. be made to do many of the tasks of much Mora savings When professional designers do a thor- more expensive equipment, and in some In addition to the obvious savings in ough job of evaluating a new design, they cases do it better. Unlike most commer- equipment cost, it's interesting to com- record the waveforms at each major node cial logic analyzers, which record only pare the number of oscilloscope traces in the system. Traditionally, that has been one's and zero's, the technique described that can be recorded on a two hour roll of done by taking Polaroid photographs of in this article works well for either digital VCR tape versus the cost of trying to oscilloscope traces. The process requires or analog signals. It was first used by the capture the same amount of information fastening the scope probe to a circuit trace author to find an intermittent failure in an on film. Assume that for recording the on a printed circuit board long enough to asynchronous coupled multi -CPU digital waveforms of a new system, each point in take the photograph, developing the print, system. It has subsequently been used for the system is recorded for 10 seconds. recording the appropriate oscilloscope debugging simpler systems. It can also be That is generally enough time to record scales, and then moving on to the next used to turn a simple oscilloscope into a the scope settings and what point in the location to repeat the process. Things pro- storage scope for reviewing transient circuit is being monitored on the voice ceed in an orderly manner when docu- waveforms. track. That yields six traces recorded per menting a new design that is working The concept is simple and rather minute, or 720 in two hours. At about 50 properly, though it surely helps to have an straightforward. All that is required is a cents a print for instant film, to record as assistant. However, when either a new de- VCR with top-quality special effects; that many traces the cost would be $360. sign or an existing system is faulty, circuit is, clean, jitter -free stop frame, fast for- Compare that to the cost of even the high- tracing usually becomes less orderly, with ward and reverse, and slow motion such as est quality T120 tape. At even faster re- the scope probe stuck here and there look- that provided by the top -of -the -line four - cording speeds an even greater savings ing for suspect signals. head units or the new digital VCR's that can be realized. Life gets even more interesting when feature digital frame storage. A video While hard copies are often desired in the system works perfectly 99% of the camera and a video monitor complete the addition to the tape recordings, the taped time, but has a glitch that causes an error list of required equipment. waveforms can be reviewed at leisure and every few hours or so. In industry, trou- A word about the video camera: A the most important ones photographed off bleshooting such a glitch generally calls high -end unit is not required; a simple the TV monitor, although with some lim-

113 Budget storage scope Having Ibund the VCR so useful in recording occasionally occurring waveform disturbances for future review, we looked into using a VCR as a "poor - man's" storage oscilloscope. Events that happen as a transient rather than a re- petitive occurrence are hard to capture on an ordinary oscilloscope. One example is speech. With so much interest in speech synthesis and speech recognition, it's FIG. 1-USING A VCR, this glitch in the system often necessary to observe the patterns clock waveform was found. created by different words and compare FIG. 5-A CAMERA/VCR SETUP is ideal for their similarities and differences. But viewing short duration transients, such as a since speech waveforms are transient in voltage interruption caused by a relay's contact bounce. nature, it's hard to do comparative work using only a standard scope. copy (photograph) from the monitor, as evidenced by Fig. 4. To get good results when using a VCR's frame -advance feature as a poor -man's storage scope requires some experimenting to obtain the proper trace intensity. Since most video cameras can accomo- date fairly low light levels, a trace barely visible when viewed directly may show up FIG. 2-FURTHER INVESTIGATION found a quite well when viewed on a TV monitor. waveform with a timing shift during alternate To set intensity, then, repeatedly trigger leading edges. the scope, adjusting the trace intensity until it looks right on the monitor. itations. Meanwhile, a very extensive set Let's close out our discussion by look- of waveforms have been captured, which FIG. 3-RINGING ON THE WAVEFORM was fi- ing at a simple application. One problem can be reviewed later if the system de- nally found to be the cause of the problem. that plagues circuit designers is that of velops a problem. contact bounce, a mechanical problem that all mechanical switches and relays A typical application are subject to. The problem that initiated the effort to Figure 5 shows the output waveform record oscilloscope traces with a VCR from a relay. When the contacts close, the was one of those periodic, hard -to -trace voltage goes high, triggering the scope. A glitches that had cropped up during the few milliseconds later, however, the con- testing of a new design. In frustration, we tacts bounce open and closed, creating a decided to record various oscilloscope momentary voltage interruption. waveforms with a VCR until one was The transient caused by the bounce can Ibund that changed appreciably just be- disrupt the proper operation of a circuit fore the system being tested recorded an and is often difficult to eliminate. But by error (since the system being tested had a using a VCR to record the scope trace, real time clock, it was possible to let it run FIG. 4-THE WORD "HELLO" as captured by a video camera and a VCR. The varying intensity you can study the waveform at leisure, to give an indication of when an error of the trace is caused by using a time base allowing you to be certain that your fix is occurred). longer than a single TV field (about 16 millise- working properly. Once an error was noted, the VCR tape conds). was advanced to the approximate time of Other uses the error and the waveforms were exam- Recording a waveform on a VCR and As you can see, a VCR can make col- ined. Finally, a glitch was found on the then playing it back a frame at a time lecting and analyzing data over long peri- system's clock wavelbrm; that is shown in allows the repetitious patterns in certain ods of time much easier, especially if you Fig. I. At first, the glitch was thought to speech sounds to be observed. Part of the can't afford an expensive logic analyzer be the direct cause of the error, but it word "hello" as captured by a VCR is or a storage scope. And a VCR can be wasn't. However, by knowing what to shown in Fig. 4. Note the non -uniform used to record any instrument's readings look for, the same conditions that created appearance of the trace. That is caused by over time. the glitch in the clock waveform (several using a time base that is longer than the For example, the author has used a high -current devices switching simulta- TV field rate of 16 milliseconds (1/(iii VCR to record changes in an oscillator's neously) were programmed, and more second). Then, the camera can not capture frequency versus temperature. After con- waveforms were recorded. a trace in a single field; instead it does so necting them to the circuit under investi- The waveform shown in Fig. 2, a sub - over two or more fields, causing a gation. a frequency meter and an clock signal. was found to be the culprit. stroboscopic effect. The fainter parts of electronic thermometer were placed side - As shown by the dual -trace leading edge, the image are seen only because of image by -side and their readings were recorded the signal's timing changed on alternate persistence on the CRT screen and/or in by a VCR as the circuit was warmed. Fast - leading edges during the time that the the camera pickup. That does not prevent forward scanning was later used to find system clock had the disturbance, causing you from examining the waveform, since appropriate temperature intervals, allow- a synchronization problem. That timing you can use the frame advance to examine ing the oscillator frequency -versus -tem- change was further traced to ringing on the event one frame at a time, but it does perature data points to be recorded very the wavetbrm, as shown in Fig. 3. make it difficult to obtain a good hard quickly. R -E

114 L. _J

This time we examine the AC characteristics of the op -amp.

TJ BYERS

.5 BEGIN WITH AN method approximates DC Avoi so close- Manufacturers often specify AvoL in Part 7op -amp characteristic ly that any discrepancy is negligible. decibels. To convert the amplification fac- that 1, measured under DC conditions, but Open -loop gain can be measured with tor into decibels, use the following for- that relates directly to AC characteristics: the test setup shown in Fig.I. First, we mula: open -loop voltage gain, or Av01,. Often must cancel the effects of input -offset AvOl (dB) = 20 log AVOL you see AvoL referred to as the large - voltage and current (V05 and 1s, respec- signal voltage gain. Basically,itis the tively) by flipping the function switch to The value of Av01, on the right-hand gain of the amplifier with no feedback. the TEST position and adjusting R7 until side of the equation is measured as de- Open -loop voltage gain is defined as the DC voltmeter indicates zero. scribed above. the ratio of the change in output voltage to Then place SI in the CAL position and Be aware that most data sheets list the voltage difference between the dif- adjust the signal generator until the AC Av01 with a specific load attached to the ferential inputs. It is measured by apply- voltmeter reads 10 volts. Return SI to the output-which usually is the minimum ing a voltage between the two inputs and TEST position and record the measurement impedance of the instrument that is used noting the change in output voltage. as VIN. Then calculate Avo1 as follows: to make the measurement. Typically, you will find the value of 121 to be 2000 ohms Open -loop gain is important because it AVOL = (MN) x 104 reflects the overall quality of the amplifier. or greater. Ideally, Avon should be infinite, but The value of AvoL is likely to exceed when we come to real -world devices, it's 50,000, and that makes it convenient to Bandwidth not. As open -loop gain decreases, there is express it as a ratio between output volts As the frequency of the input signal a corresponding deterioration in drift, sta- and input millivolts. A value of 50,000, increases, open -loop gain decreases. bility, input impedance, output imped- for example, corresponds to 50V/mV. Many reasons are cited for that, but the ance, and bandwidth. In fact, you can measure the value ex- major cause is reduced performance by Although op -amp manufacturers spec- pressed by the ratio directly by setting the the transistors in the op -amp. ify large -signal gain fora DC input, AvoL input voltage to 100 mV (rms) and reading What occurs, in essence, is that the is generally measured with a 5 -Hz AC the value on the 10 -volt scale of the AC output voltage of the operational amplifier signal. Doing so greatly simplifies the meter (in the CAL position). A reading of I remains stable up to a point. After that measurement, and the frequency is low volt indicates a ratio of 10V/mV, and a point, open -loop gain drops off rapidly, as enough that the AVOL obtained by that reading of 10 volts represents 100V/mV. shown in Fig. 2. It is generally agreed that

115 drivers are particularly susceptible to St FUNCTION being unable to handle large -signal in- CAL puts. The problem lies within the output R3 TEST stage of the op -amp. Because of design AC 1K requirements, the output transistors expe- A4V VOLTS CAL rience a high. degree of charge retention. In other words, it takes a while for them to :RI R2 7. 'IOW) 0100K TEST change from one phase to the next. DC VOLTS Let's say, for example, that we have a

15V squarewave input that has been adjusted to R4 give us a squarewave output that swings 1K R6 the entire ± voltage range. The moment 100K R7 50K *Rj the input signal changes states, the output (1/4.,1000Hz Ws. TRIM tries to follow. However, inter -element ca- R5 pacitance (and inductance) prevent it from i100() 15V making the transition instantaneously. Consequently, the output pulse takes lon-

ger to reach its plateau than the original =. input signal did. The time it takes for the output voltage FIG. 1-MEASURE OPEN -LOOP GAIN (Avop after adjusting R7 for null output. to correspond to the input voltage is called

120 so that the meter reads 1 volt. Now in- the slew rate. Slew rate is expressed in

100 crease the input frequency until the meter volts of change per microsecond. co reads 0.707 volt. That is the 3 -dB band- Slew rate is a linear function. If, for 80 width point, or BWOL. example, the slew rate is 2 volts per mi- z 60 Continue sweeping the frequency crosecond, then it will take 5 microse- 4 40 LLI while keeping your eyes on the meter. You conds for the output to change 10 volts. CD V2C 4 20 will notice a pronounced decline in output No matter how quickly the input signal as you do. When the output voltage de- may rise, the output can not respond any g 0 - 20 creases to about %moo of the input (I milli- faster. 1.0 10 100 1.0K 10K 100K 1.0M 10M volt) you have reached the unity -gain Slew rate (designated SR) is measured FREQUENCY- Hz bandwidth, fT. For an accurate measure- using the circuit shown in Fig. 3. Notice that the op -amp is configured as an invert- FIG. 2-FREQUENCY RESPONSE of an op -amp ment, you must make sure that the input is constant up to a point, after which It drops off voltage remains constant during the fre- ing amplifier. The input is a low -frequen- at a rate of 6 dB per octave. Cutoff frequency (fT) quency sweep. cy squarewave of about 100 Hz. The is reached when the amplitude of the output amplitude of the input signal is adjusted voltage equals that of the Input signal. Gain -bandwidth product Another commonly specified op -amp after the gain decreases by 3 dB (i. e., falls characteristic is called Gain-BandWidth R2 to 70% of its original value), the decline in product, GBW. Essentially, it is the prod- performance makes it undesirable for uct of the small -signal open -loop gain and many applications. Consequently, the the frequency at that gain. It is expressed 0 VERTICAL open -loop bandwidth, BWOL, is spec- by the formula: 0 INPUT ified at the -3 -dB point. Further increases in input frequency GBW = AVOL X f 100F1/ cause further reduction in output voltage There is no standard frequency at at the rate of 6 dB per octave. Eventually a which GBW is measured, but most man- point is reached where the amplifier's gain ufacturers arbitrarily specify GBW some- equals one (unity gain). That is, the ampli- where around 100 kHz. The actual test FIG. 3-SLEW RATE is defined as the amount of tude of the output signal equals that of the frequency may vary and can range from as time it takes for the output voltage to correspond to a change in the input voltage. The slew input signal. Not surprisingly, thatis low as I kHz to as high as 10 MHz. rate is expressed in volts of change per microse- called the unity -gain -bandwidth factor. cond. Sometimes unity -gain bandwidth is Slew rate simply listed as BW, implying total band- Whereas bandwidth indicates how the width, rather than the -3 -dB bandwidth. op -amp is able to handle small -signal ana- V,, But more often than not, it is described as log inputs, it provides little information Continuing increases in input frequen- on how the amplifier can handle digital cy beyond that point result in negative and large -signal inputs. amplification, or attenuation. Digital pulses are unique in that, even Both bandwidth parameters can be though the frequency of the waveform (ac- measured using the circuit shown in Fig. tually, its repetition rate) may be low, I. First stabilize the amplifier by compen- bandwidth requirements are quite high. It VII, 0 sating for any offset values-you do that is not unusual for digital pulses to have \V using the procedure outlined earlier. It is risetimes on the order of five nanose- V not necessary for the amplifier's DC out- conds; a five nanosecond risetime corre- \V sponds to a frequency of 200 MHz! S. put to be at exactly zero volts, but too t much of an offset will give a false reading. The op -amp experiences similar prob- FIG. 4-SLEW RATE is determined by measur- Next, set the generator to deliver a 5 -Hz lems when trying to process large output ing how long a signal takes to rise from 20% to signal, and adjust the generator's output signals. Amplifiers used as high -voltage 80% of the total voltage swing.

116 so that the output swings over the entire ± power -supply voltage. SR is measured

on an oscilloscope by noting the amount R3 DC of time it takes for the waveform to pass 1K through the 20% and 80% points on the VOLTS waveform, as shown in Fig. 4. S<13, DC

R1 R2 ()L.! AC AC Settling time 100.(.! 100K -)0 S2 VOLTS A closely related parameter is settling 15V R4 C1 1K R5 10012F 100K R7 25V 50F, C., 1000Hr TRIM R. R6 INPUT 100!). 15V

OUTPUT

FIG. 8-OUTPUT IMPEDANCE may be determined by first nJIling the op -amp for zero offset error and then adjusting RL for one-half output. The value of RL equals the output impedance.

DIODE NOISE ALLOWABLE GENERATOR SETTLING ERROR TIME BAND FIG. 5-SETTLING TIME is defined as the amount of time the output signal takes to stabilize at its final value.

R2 10K

J1 RI INPUT 10K J2 OUTPUT

FIG. 9-NOISE FACTOR (NF) is measured with a diode noise source and a 3 -dB attenuation pad.

R4 time, which is defined as the time re- Settling time (ts) which is sometimes 10K quired, after the application of a step volt- listed as step response, is measured ac- age (such as squarewave), for the output cording to the tolerance of the overshoot FALSE D2 voltage to settle and remain within a spec- bandwidth. Typically, settling -time re- SUMMING 1N916 NODE ified error band around the final value. sponses are measured in steps, beginning ALL RESISTORS MATCHED As you can see in Fig. 5, a normal step with 10 percent. That is, when the ringing TO WITHIN 0.01% function causes the output to swing wider (the damped oscillation) has contained it- FIG. 6-SETTLING TIME is measured on an os- than it should, both overshooting and un- self within 10 percent of the target value, cilloscope using a false summing node. dershooting the final value, in a gradually settling time has been reached. In high - reducing series of damped oscillations. precision circuits, tolerances of 0.1 and Eventually the signal arrives at the proper 0.01 percent are not uncommon. AC output voltage. The time it takes to ac- VOLTS The lower the loop gain, the faster the complish that feat is called the settling settling time. Settling time depends on time of the op -amp. feedback from output to input, so the You can measure settling time using the higher the loop gain, the longer it takes for circuit shown in Fig. 6. To measure the the amplifier to overcome external influ- settling time of the op -amp accurately, a ences within the loop. "false summing node" has been created. Although it might seem that the best place Power gain to measure settling time would be at the The Power Gain (PG) of an op -amp is output of the op -amp, stray capacitance on expressed in decibels. It is the ratio of the the test probe makes it impossible to re- signal power developed at the output to solve settling time to better than 0.1 per- the signal power applied to the input. 1000Hz PG 10 log (Y__P! cent. The false node eliminates the error z Power gain may be measured using the 0 by isolating the oscilloscope from the am- circuit shown in Fig. 7. The test is made m plifier under test. However, because of the by adjusting the value of RI so that the co voltage divider composed of R4 and R5, input voltage to the amplifier under test is m FIG. 7-POWER GAIN is the ratio of the signal only one-half the actual error voltage ap- one-half the voltage output of the signal power developed at the output to the signal pears at the false -summing node-a fac- generator. Because RI is in series with the co power applied to the input. tor that must be taken into account. continued on page 130 co

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121 -V7L 7-1 0 r\\. L

One of a series of new kits from Europe, this clock module is easy to build and fun to use.

IN EUROPE, THE NAME TSM IS SYN- driver. Note that the IC is a proprietary component locations clearly indicated. onymous with educational and useful device and that it is available in the The patterns also are shown in PC Ser- electronics kits for the hobbyist. Now, U.S. only as part of the 201 kit. vice. some of their products are available in this The circuit includes two other IC's: The circuit is extremely easy to build; country. Because the kits fill an important One, IC2, is a CD4060 ripple counter, the most difficult task is making sure all need for hobbyists, especially beginning which is configured as a crystal oscillator. components are oriented correctly. A ones, we'd like to take some time to intro- Trimmer C5 allows precise tuning of the parts -placement diagram for the main duce them to you. In this article, we'll oscillator frequency. The other, ICI, a board is in Fig. 2; the parts -placement look at one that's typical of the line-an CD4027 dual J -K flip-flop, divides the diagram for the display board is in Fig. 3. easy -to -build, versatile crystal -controlled output from IC2 to provide IC3 with the Since most of the components mount clock module. proper time -base signal. on the main board, let's start there. First, The clock and alarm functions are con- mount the five jumpers; note that one runs Use it anywhere trolled by four pushbutton switches. The beneath the socket for ICI. Stuff the board The TSM 201 clock module is excep- hour and minute settings are set using S3 with the remaining parts, starting with the tionally adaptable. Powered by AC or and S4; the alarm is set using S2; and the low -profile devices. Be sure to use IC DC, it can be installed virtually any- alarm is turned on or off with SI. sockets for the IC's. Connect the pushbut- where-in another piece of equipment; in A half -wave rectifier made up of D5 and tons to the appropriate points on the board the dash of a car, truck, or boat; or even in Cl allows the unit to operate from either using wires. a cabinet by itself. The device features an an AC or a DC power supply. For DC The four 7 -segment displays are located alarm output that can be used to control operation, use a 12- to 24 -volt power on the display board. Before mounting another circuit, or to sound the optional source. For AC operation, use a step- them, however, be sure to install the two TSM 1/4 buzzer. Time readout is provided down transformer to provide a 9 -12 -volt jumpers. by four 8 -mm 7 -segment LED displays, input. The two boards are normally connected which can easily be seen from across a using a right-angle male header. However, room, or on the road at night. Building the circuit just about any scheme can be used. A schematic diagram of the circuit is All components, except the pushbutton shown in Fig. I. The heart of the circuit is switches, are mounted on two PC boards. Setup and use IC3, a custom Texas Instruments TMS The 20/ kit, available from the suppliers Apply power, being careful to observe 3899 clock IC that provides all of the mentioned in the Parts List, includes two the proper polarity. A flashing display inclock and alarm functions, and the display etched and drilled PC boards, with all dicates that the clock is working correctly.

122 R2 CS D3 S3 PARTS LIST 1K 3 30PF 1N914 -,01--00 All resistors 1/4 watt, 5% unless other- ITAL 1 C2 04 S4 wise noted 3 2/6 MHz 22pF 1N914 R1-7.5 megohms -Wirel ÷1---0 0 R2-1000 ohms RI CI D2 S2 R:_:-6800 ohms lOpf / 5 1N914 R4-1.8 megohms MEG 0 Capacitors K 01 Si 101 1N914 C1-10 pF 12 o C2-22 pF C3-0.1 ji.F 4060 C4-470 RF, 25 volts, electrolytic CE -3 pF-30 pF, trimmer, PC mount 16 8 49 01516 Semiconductors 3 R3 IC i-CD4027 dual J -K flip-flop 2 10 IC2-CD4060 14 -stage binary ripple 13 1 6141.81(71 7 9 counter -41 1 8 -6 9 TMS 3899 5 5 IC3--TMS 3899 clock IC (Texas

8 3 4 Instruments) 10 11 4027 7 8 2 D1-D4--1N914 or equivalent 11 --- 12 6 3 D5 -1N4001 or equivalent 16 12 *--1(-- 4 DISP1 DISP2 DISP3 DISP1-DISP4-7-segment LED display, C3 .1 common cathode C4 Other components R4 47011F X1AL1-3.2768-MHz quartz crystal 1.8 25V MEG S1-S4-pushbutton switch, momentary K contact. normally open D5 Miscellaneous: PC boards. wire. solder. 1N4001 etc. o NOTE: The TSM 201 kit is available for 12-24 VDC ALARM 526.77, plus $1.50 shipping and han- OR OUT dling, from the following suppliers: 9-12 VAC ISM in America, Inc, 2065 Boston Post Road, Larchmont, NY 10538; FIG. 1-THE HEART OF THE CLOCK CIRCUIT is IC3. a proprietary clock IC. Note that it can be obtained Nutron Computer Electronics, 821 E. in the U.S. only as part of the TSM 201 kit. Roosevelt Road, Lombard, IL 60148; Auto Sound Systems, 1269 East Main St., El Cajon, CA 92021. The Set the correct time using S3 and S4. If played time and the actual time corre- optional TSM 114 Buzzer Kit is avail- you have a frequency counter. connect it spond. able for $7.38, plus shipping and between pin II of IC2 and ground. Then The clock is now ready for use. If you handling, from the same suppliers. adjust C5 fix a frequency of 3.2768 MHz. wish to take advantage of the alarm func- nclude proper state sales tax, if ap- If you don't have a counter, set C5 to tion, connect the TSM /14 buzzer circuit, propriate. The 201 kit does not in - midrange and allow the clock to run fin- a or anything else that you wish to control, :Jude battery, AC power transformer, day or so. Then, compare the time display between the positive side of the supply or case. to the actual time. If the clock is running and the alarm output. fast, decrease the capacitance of C5 slightly: if it is slow, increase the capaci- Impressions DISP2 DISP3 DISP4 tance. Allow the clock to run another da%. With a catalog of over 200 kits. TSM is then check again. Repeat until the Eli one of Europe's leading suppliers of kits. 31 JI

DISP3 D5 < DISP4 -< DISP2 +O I C2 --0 -CS- DISP1

C4 XTAL1 0_ R2 _inF S3 FIG. 3-MOUNT THE FOUR DISPLAYS on the r-os2 R1 "-' display board. Note that one of the jumpers runs ci -T- -T- beneath DISP4. JI 0 0 F°S1G- -R3 S4 R4-- If the 20/ is any indication, they should enjoy similar success in this country. DI D2# IC3 D3 D4 J Those who purchase the kit will be pleas- ed to note that it is professionally prepared J I \ ALARM OUT and packaged. Further, its designed to be used with little modification in almost any DISP3 timekeeping or timing application. The > DISP4 only negative is that the instructions are a DISP2 little rough around the edges due to trans- A f E D P B G DISP1 lation problems. Despite that, they are FIG. 2-MOST OF THE COMPONENTS mount on the circuit's main board. easily followed. R -E

123 STATE OF

/bLIIIF)4:) STATE ROBERT F. SCOTT, SEMICONDUCTOR EDITOR

A NEW AND INTERESTING MONOLITHIC reset) when the pin 2 voltage (V,) device for process -control ap- v is greater than the set -point volt- plications is the LTC1041 "bang - vus,(s) age plus delta and the pin 1 voltage COMP bang" controller from Linear Tech- A is high when the pin 2 voltage is nology Corp. That CMOS compo- ON/ less than the set -point voltage nent takes its name from its ability OFF minus the delta voltage. That ac- to turn a control element either tion produces a very precise hys- fully ON ("bang") or fully OFF ("- SET terisis loop with a deadband of bang"), with no middle ground, to POINT twice the delta voltage centered around the set point as shown in regulate the value of the param- DELTA eter being controlled. Fig. 1-b. The LTC1041 has many ap- Figure 1-a shows an operational plications in instrumentation and GND 4 block diagram of the LTC1041 along process control. Figure 2 shows OSC TIMING be used in an ultra -low - with the pinout of its 8 -pin DIP GENERATOR CIRCUIT VPP housing. The SET POINT input deter- power (2.4 I.LW) thermostat. The mines the average control value circuit shown is suitable for tem- POWER ON- 7 perature regulation over a range of and the DELTA input establishes the V "deadband". As show in Fig. 1-b, +50°F to +100°F. 800 4+2 Complete specifications and ad- the deadband is centered on the 4RExT set -point voltage and is twice the ditional applications, including a voltage at the DELTA input. An un- DC -motor control and a battery - .1% CEXT usual sampling technology allows charger control can be found in independent control of the dead - a the 1986 LTC Linear Databook. The band and the set point; there is LTC1041 costs approximately $5.50 absolutely no interaction between each in small quantities. For addi- the two. tional information on the device A series RC network, connected .4 --SET POINT-P. and on the data book, write to Lin- to pin 6, controls the oscillator fre- -DELTA ear Technology Corp., 1630 McCar- quency and therefore determines thy Blvd., Milpitas, CA 95035-7487. the sampling rate. Power is applied V to the two on -board comparators GaAs amplifier brief for approximately 80 1.ts at the start Using the Anadigics ADA25001, of each sampling period. During DC-2.5-GHz Amplifier is the title V that time, the inputs to the analog A of an applications technical brief section are sampled and com- giving detailed information on the pared. Power is removed from the use of GaAs (gallium -arsenide) GND Vt Vu monolithic amplifiers produced comparators as soon as they have OV completed their task. The CMOS INPUT VOLTAGEIVINI by Anadigics, Inc. It begins with a logic holds the output continu- description of the ADA25001 DC- ously while consuming virtually to-2.5-GHz amplifier, a GaAs de- no input power. vice designed for high gain and Each of the two comparators has wide bandwidth in high -data -rate two differential inputs. When the put ishigh when the sum of its fiber-optic systems, radar pro- sum of the voltages on a com- inputs is positive. The inputs are cessors, high-speed pulse ampli- parator's inputs is negative, the interconnected so that the pin 1 fiers, and clock -driver applica- output is low; a comparator's out - voltage is low (the RS flip-flops are tions.

124 TO Test RS232C 26VAC 2WIRE THERMOSTAT In A Zip Cl RI 560 0.11.LF t Is R2 t R3 400nA lest RS232C data 4.32K j 4.99K communications interfaces-like R4 R8 computers to 5K ICI 10MEG printers, computers LTC1041 6 to modems, and computers B1 R5 to computers-fast and 6V 6.8IK east in the palm of your

R7 hand with Beckman Industrial's DELTA 0.5F low-cost, easy -to -use line of testers. Each R6 - C2 is self-contained in a lbughpak case, 49.91/ including five models in a durable zippered T10 pouch, and a 10 -year warranty on every "SEE TEXT ALL RESISTORS model.Pricesstartas lowas 849.95. EXCEPT R5 AND R7 ARE 1% Ir. The application discussed in the to Siliconix customers. Contact brief is the layout of a single -stage Siliconix Telemarketing at See your nearestBeckmanIndustrial amplifier using the ADA25001 to 800-554-5565 or 2200 Laurelwood distributor today, or send for free provide flat gain response from 100 Road, Santa Clara, CA 95054. brochure We'll send it to you in azip. kHz to 2.5 GHz over a temperature range of -55°C to +125°C. The New tone ringer Quick Cable Customizing layout includes a temperature - The LS1240A is a recent addition Fast RS232C Interfacing and Testing compensation loop. The brief is to the SGS Semiconductor family LED Identification of Cable available upon request to Mr. of economical two-tone tele- Configurations Michael P. Gagnon, Anadigics, Inc., phone -ringer devices. The new Pocket and Handheld Compactness 35 Technology Drive, Warren, NJ ringer has a high output -current 07060. capability (150-mA maximum), Speeds Up Trouble shooting which is sufficient to drive low- 10 Standard Low -Cost Models Computerized FET databook cost dynamic transducers having Designers who use small -signal impedances as low as 50 ohms. FET's can now quickly select the The new ringer, which is pin - wit. best device for a given application compatible with the standard - - by using the Siliconix Comput- LS1240, generates an alternating o a erized Data Book, which provides two-tone drive signal for the trans- . : full details on the company's FET ducer. The tone frequency and the ....".. : product line on a 5A -inch floppy alternation rate are continuously disk for an IBM PC or PC -compati- variable and externally adjustable. ble computer. The disk also con- The required supply voltage is tains an updated version of the derived from the AC ring signal MOSPOWER Computerized Data and the circuit is designed so that Book, originally released in 1986. noise on the line or variations in The FET section prompts the the ringing signal current cannot ... user to select one of seven major affect correct operation of the . application areas such as ampli- ringer. An external polarity -guard fiers, analog switches, current reg- bridge and a protection Zener di- Easy BOB '.' 750 ulators, diodes, dual amplifiers, ode allow direct connection to the EasyPATCEF. 704 mixers/oscillators, and voltage - telephone line. The IC's low cur- controlled resistors. A list of key rent consumption permits up to parameters is then generated on four of the devices to be operated rviceents, the screen, and the user is in- in parallel. The LS1240A comes in structed to enter a range of accept- an 8 -pin miniature DIP and re- IkeleThe One. able parameter values. In requires only six external compo- Etrasr-linin irrri...-ri=4 sponse to those entries, the type nents. The price is $0.82 each, in Heckman Industrial torporalion Instrumentation Products Mt mon numbers of appropriate Siliconix A StAssidiary of Emerson Electric Company minimum quantities of 1000. SGS 388' Ruffin Rd.. San Diego. California 92123 1898 FET's are displayed. Semiconductor Corp., 1000 Bell 16194 565-4415 FAX (619) 268.01"2 TLX 249031 © 198' Beckman Industnal Corporation The data book on a floppy is free Road, Phoenix, AZ 85022. R -E

CIRCLE 98 ON FREE INFORMATION CARD 125 er NF. The 50 -ohm measurement is pre- POWER TRANSISTORS ferred for production testing because it ( untamed front page /12 requires no tuning and can be done with automated test equipment: fly that reason, it is frequently the value specified on data change in Vrc. Changes as small as Irk are sheets. Likewise, gain is normally specified readily detectable, with 5'4 or less nor- for best NF conditions and for a A of 50 mally considered an acceptable limit. To- ohms. day's most sophisticated device specifications for RF power transistors use that Impedance parameters criteria to determine "success" or RF power transistors arc typically charac- "failure" in ruggedness testing. terized by impedance parameters rather than small -signal S + parameters. Both Z, and Other specs Z,,,,, of a device are determined in a similar I )uta sheets ior low -power RF transistors way: i.e.. place the device under test in a show such special characteristics as noise circuit and tune both the input and output FIG. 7-RF POWER TRANSISTOR IMPED- (NF),ina.vinnon available gain circuit elements to achieve maximum P at ANCES are determined by measuring the (GU,,,) and scattering (S) parameters. The the desired frequency of interest. At max- characteristics of a working circuit. S parameter is normally taken with the de- imum output power, the impedances of the vice under test in a standard commercial device under test will mathematically repre- impedance is shown in Fig. 7. fixture. Typically. they are given as func- sent the input and output network imped- The entire impedance measuring process tions of frequency and 1. ances. Thus, terminate the input and output is somewhat difficult and time-consuming NF and GNF likewise use commercial ports of the test circuit, remove the device because it must be repeated for each fre- equipment such as the Eaton 4012 gain - and measure impedance looking from the quency of interest, using a test circuit that noise analyzer. or the HP8970A noise figure device: first, toward the input to obtain the will tune the frequency range. Different cir- meter. A transistor's NF will vary with input conjugate of Z, and, second, toward the cuits must he designed and built for other impedance match, and as a result is gener- output to obtain An, which is normally frequencies, which explains why it is some- ally measured in a test fixture having input given as the load required to achieve max- times difficult to get a semiconductor man- tuning. Usually. data is given with a circuit imum P. ufacturer to supply impedance data for tuned initially for lowest possible NE and A network analyzer is used in the actual special conditions of operation, such as dif- then for a standard 50 -ohm input. Measur- measurement process to determine the com- ferent frequencies. different power levels, or ing NF at a 50 -ohm input impedance (Z,1 is plex reflection coefficient of the circuit. A different operating voltages. more repeatable. but normally yields a high- typical measurement setup for measuring Tradeoffs in specifications Gain and ruggedness are the most obvious device parameters for compromise NOISE REDUCTION in RF power specifications. Devices with high gain-high with respect to their fig- FOR UNDER $10. ure of merit (emitter periphery/base area)-tend to be fragile: i.e., not rugged. Eic) 414/NG &°P By using materials with higher resistance, LOGf'" with a thicker epitaxial layer, and/or in- PL -1--014 PH creased values of emitter resistance, rug- 1,0, PH SWITCHES How to live gedness can be enhanced at the expense of PATCHBAYS with someone gain. Likewise, to get higher gain, the MICROPHONE who's living user may be asked to accept lower collec- FADERS, POTS CONNECTORS with cancer. tor/base breakdown voltages (BV(.BO, or CABLES When one person gets BVcEs and BVcE0) in order to reduce TER/14/AIAL cancer. ever) one in the family SNAKE STR/PS suffers collector resistance and thereby increase Spe Noht nly knows better than 44-6.6, we do how much help and gain. Transistors designed for operation cONIACS understanding is needed. That's why our service and rehabili at high frequencies can be used at lower latlIM programs emphasize frequencies to obtain increased gain, but the whole family, not lust the BP1/41-TEB\I CRAMOLIN cancer patient. such devices will usually be fragile at the Among our regular services we provide inhirmatum and lower frequency. Even the finest equipment in the world cannot guarantee noise -free operation. guidance to patients and lamdies. One "dirty" connection anywhere in the electrical path can cause unwanted transport patients tie and trim noise or signal loss treatment. supply home care Summing up items and assist patients in their return to everyday life The RF power transistor is an unusually Life is what concerns us. The "MORE THAN A CONTACT CLEANER" life of cancer patients The lives of complex semiconductor device and diffi- their (mikes So you can see we cult to fully characterize. Not all informa- CRAMOLIN is a fast -acting, anti -oxidizing lubricant that cleans and are even more than the research organizaie in We are SO well tion about RF-transistor characteristics preserves all metal surfaces, including gold. known En Be When applied to metal contacts and connectors. CRAMOLIN removes faces cant er alt /11C have been explained in this article, nor are resistive oxides as it forms a protective molecular layer that adheres to the metal AMERICAN CANCER SOCIETY all usually covered in a data sheet. The surfaces and maintains maximum electrical conductivity. circuit -designer should contact the man- CRAMOLIN'- USED BY THOSE WHO DEMAND THE BEST: ufacturer for more -detailed information Bell & Howe, Hewlett Packard MCI(Sony) Nakamichi whenever itis appropriate. Most, if not Boeing John Fluke Mtg. Motorola RCA Capitol Records McIntosh Labs NASA Swechcrelt all, manufacturers of RF transistors have SINCE 1956 extensive applications support for the ex- CAIGLABORATORIES .- press purpose of assisting the circuit designer whenever and wherever assistance 1175-0 Industrial Ave fP 0 Boo JI- Escondido. CA 92025-0051 USA 1619) 743-7143 is needed. R -E CIRCLE 189 ON FREE INFORMATION CARD 126 PC SERVICE

2'/8 INCHES

MOST OF THE COMPONENTS for the TSM 201 clock module THE CLOCK'S FOUR LED DIS- are mounted on this board. PLAYS mount on this board.

127 PC SERVICE

One of the most difficult tasks in building any construction project featured in Radio -Electronics is making the PC board using just the foil pattern provided with the article. Well, we're doing something about it. We've moved all the foil patterns to this new section where they're printed by themselves, full sized, with nothing on the back side of the page. What that means for you is that the printed page can be used directly to produce PC boards! Note: The patterns provided can be used directly only for direct positive pho- toresist methods. In order to produce a board directly from the magazine page, remove the page and carefully inspect it under a strong light andor on a light table. Look for breaks in the traces, bridges between traces, and in general, all the kinds of things you look for in the final etched board. You can clean up the published artwork the same way you 7 clean up you own artwork. Drafting tape and graphic aids can fix incomplete traces and doughnuts, and you can use a hobby knife to get rid of bridges and dirt. An optional step, once you're satisfied that the artwork is clean, is to take a little bit of mineral oil and carefully wipe it across the back of the artwork. That helps make the paper transluscent. Don't get any on the front side of the paper (the side with the pattern) because you'll con- THE MOST POPULAR taminate the sensitized surface of the WIRE -WOUND CB ANTENNAS copper blank. After the oil has "dried" a IN THE WORLD bit-patting with a paper towel will help speed up the process-place the pattern Because... they perform! front side down on the sensitized copper blank, and make the exposure. You'll FACT probably have to use a longer exposure time than you are used to. When CB was legalizedin England, We can't tell you exactly how long an `Firestik' antennas were barred from sale exposure time you will need as it depends because the emitted signal was too strong. Fortunately. no other country, on many factors but, as a starting point, including the U.S.. limits antenna figure that there's a 50 percent increase in efficiency exposure time over lithographic film. But you'll have to experiment to find the best method for you. And once you find it, stick YOU CAN HAVE SECOND with it. Finally, we would like to hear how you BEST OR, Tirestile! make out using our method. Write and tell us of your successes, and failures, and Call or Write for FREE Catalog what techniques work best for you. Ad- Tirestik' Antenna Company dress your letters to: 2614 East Adams Radio -Electronics Phoenix, Arizona 85034 Department PCB (602) 273-7151 500-B Bi-County Blvd. Farmingdale. NY 11735 MILLIONS OF SATISFIED OWNERS

CIRCLE 100 ON FREE INFORMATION CARD CIRCLE 108 ON FREE INFORMATION CARD 128 high schools taught honesty and ethics. BLUE BOX Mom and Pop didn't have the chance to ATTENTION! continued from page 52 take college courses inStealing 101that masqueraded under quaint names such as office to silence the ringing signal. When Business Management, Marketing, or Ar- ELECTRomici Pop released S4, the folks can talk to bitrage.When Junior tried to get the old Junior without Junior getting charged be- folks to use his "free telephone" they just cause his AMA tape did not show his call wouldn't go along. So Junior installed the CHNia was answered-the DC loop must be Red Box at his end. He gave one ring to gra closed for at least three -seconds for the notify the family to call back. When Pop EARN YOUR \ e,L) AMA tape to show Junior's call was an- called Junior, it was Junior who was using swered. All the AMA tape showed is that the Red Box. Problem was, Junior didn't B.S.E.E. Junior let the phone ring at the old home- know that the AMA tape for Mom and stead for almost 30 minutes; a length of Pop's phone showed a 20- or 30 -minute DEGREE time that no Bell Operating Company is ringing. When Ma Bell's investigators THROUGH HOME STUDY likely to believe twice! showed up it was at the old homestead; Our New and Highly Effective Advanced -Place- A modern Red Box is simply a con- and it was only then that the folks dis- ment Program for experienced Electronic Tech- ventional telephone that's been modified covered their pride and joy had been nicians grants credit for previous Schooling and to emulate the vintage 1940 military field taught to steal. Professional Experience, and can greatly reduce the time required to complete Program and telephone. Aside from the fact that the There are no hard facts concerning how reach graduation. No residence schooling re- operating companies can now nail every many Red Boxes were in use, or how quired forqualifiedElectronic Technicians. Red Box user because all modern billing much money Ma Bell lost, but one thing is Through this Special Program you can pull all of the loose ends of your electronics background equipment shows the AMA information known: she had little difficulty is closing together and earn your B.S.E.E. Degree. Up- concerning the length of time a caller let down Red Boxes in virtually all instances grade your status and pay to the Engineering the target telephone ring, it's use has often where the old folks were involved because Level. Advance Rapidly! Many finishin12 months or less. Students and graduates in all 50 put severe psychological strain on the Mom and Pop usually would not tolerate Stales and throughout the World. Established users. what to them wasstealing.If you as a Over 40 Years! Write for free Descriptive Lit- Does getting electronics mixed up with reader have any ideas about using a Red erarure. psychology sound strange? Well it isn't Box, bear in mind that the AMA (or its because it's what helped Ma Bell put an equivalent) will get you every time, even COOK'S INSTITUTE end to indiscriminate use of the Red Box. if you use a phone booth, because the OF ELECTRONICS ENGINEERING The heyday of the Red Box was the 1950's record will show the number being called, 347 RAYMOND ROAD and 1960's. Mom and Pop were lucky to and as with the Blue Box, the people on E.P.O. BOX 20345 have finished high school, and almost the receiving end will spill their guts to CI JACKSON. MISSISSIPPI 39209 R -E without exception, both elementary and the cops. CIRCLE 197 ON FREE INFORMATION CARD

ELECTRONIC LOCK TRANSAM ELECTRONICS continued from page /08 YouCan Be 383 CANAL ST NYC, NY10013(-.<) (212) 226-3893 ..--Y--' One Of The one for the common signal and electrical ELECTRONIC KITS r.... i 4 4 ground. 20,000 Technicians 10 LED CHASER KIT -10 LEDSCHASE IN ONE Build the encoder circuit on a small, DIRECTION AT VARIABLE SPEEDS. SKILL LEVEL - piece of perforated wiring board, and, if Certified BY ISCET EASv $8.95 ALTERNATING FLASHER KIT -2 9V BULBS possible, use a socket for IC2, because FLASH ALTERNATELY AT A VARIABLE SPEED. being a CMOS device, it can be damaged GREAT FOR MODEL TRAINS. SKILL LEVEL - EASY $7.95 if you solder directly to its terminals, es- The International Society Of Certified pecially if you're using an ungrounded Electronics Technicians offers permanent STARBURST KIT -25 LEDS IN THE SHAPE OF A certification by administering the CET STAR OSCILLATING AT VARIABLE SPEEDS. SKILL soldering iron. For the same reason, use a exam with the FCC recognized communi- LEVEL - HARDER $14.95 socket for the decoder's ICI. cations option for $20. A second exam 16 LED BACK AND FORTH KIT -16 LEDS CHASE on FCC regulations for a $10 fee is re- BACK AND FORTH AT VARIABLE SPEEDS. SKILL As shown in Fig. 3, the small encoder quired for a Radiotelephone License. LEVEL - HARDEST. $14.95 assembly can be secured directly to one Upon passing, technicians receive both a ALL KITS COME WITH PC BOARD AND ALL PARTS permanent Radiotelephone Operator Cer- ANDOIAGRAM NECESSARY FOR CONSTRUCTION. side of a DB-25-type connector hood tificate and a CET Certificate issued by THESE KITS REQUIRE 9 VOLTS DC. PLEASE SPEC- using two 4-40 screws. ISCET. IFY RED. GREEN OR YELLOW. SWITCHING POWER SUPPLY-BUILT FOR APPLE III THIS UNIT MEASURES 41,2"x 17" . 3" HIGH. Testing SWITCHABLE FOR 110 OR 220VAC. COMPUTER Testing is very simple. Connecting the TYPE PLUG FOR THIS UNIT ADD $3.95. VALUES ISCET Offers License Renewal ARE- + 12VDC (a 2.5 AMPS. 12VDC (a 0.3 AMPS, key to the decoder should cause RYI's +5VDC (a 4 AMPS. 5VDC (a0.25 AMPS. WAS $49.95... NOW... $24.95! contacts to close.If the contacts don't ISCET has developed a program for regis- TELEPHONE LINE TESTER-THIS nt.'"*.Z close, it's more than likely the problem is tration of those who currently hold a SMALL UNIT ALERTS YOU TO PROP- an address mismatch between encoder valid Radiotelephone Operator License. ER CONNECTION OF PHONE LINES. By sending a completed application, a USES LED INDICATOR $4.95 EACH and decoder. Check that they are exactly photocopy of your FCC License, and $10 the same. If you connect an oscilloscope PLUG IN IN WALL TRANSFORMERS your license will be renewed with the (ALL PLUG DIRECTLY INTO 117VAC) to pin 15 of 1C2 should see a constant assurance of a recognized national tech- 6VDC (a 500 MA $3.95 sequence of pulses being transmitted out nicians association behind it. 12 VDC (a 300 MA $3.95 12VAC (a 930 MA $4.95 of the encoder. If the pulses are missing 14VDC (a' 500 MA $3.95 check that resistors R4 and R5, and ca- For More Information Contact: TERMS: $10 MINIMUM ORDER. ADD $2.50 FOR pacitor C3. are connected correctly. R -E SHIPPING (SOME MAY REQUIRE ADDL.). ADD 8.25 ISCET 2708 W. Berry, Ft. Worth, TX TAX IN NY. CALL IN OR MAIL IN ORDER WITH 76109.(817) 921- 9101 CHECK. VISA M C AMEX OK ALL ITEMS SUBJECT TO PRIOR SALE. 129 CIRCLE 211 ON FREE INFORMATION CARD Rates: Ads are 21/4" x 21/2". One insertion S825. Six insertions $800 each. Twelve insertions $775 each. Closing date same as regular rate card. Send order with remittance to Engineering Admart, Radio Electronics Magazine, 500-B Bi-County R -E Engineering Admart Blvd., Farmingdale, NY 11735. Direct telephone inquiries to Arline Fishman, area code -516-293-3000. Only 100% Engineering ads are accepted for this Admart.

117 PRACTICAL IC FCC LICENSE PROJECTS BUILD YOU CAN 26451-117 PRAC- PREPARATION TICAL IC PROJECTS 117 PRACTICAL The FCC has revised and updated the YOU CAN BUILD IC PROJECTS $10.95. Dozens of youCAN 11111 D commercial license exam. TheNEWEXAM fully -tested, ready -to - covers updated rules and regulations build circuits you can transistor and digital circuitry. put together from THE GENERAL RADIOTELEPHONE readily -available, low OPERATOR LICENSE - STUDY GUIDE cost IC's! There are a contains the necessary preparation for total of 117 IC circuits ONLY $25.00. ranging from an audio mixer and a signal splitter to a tape -deck amplifier and a top - ASK ABOUT OUR OTHER STUDY PROGRAM octave generator organ! From TAB Books. To order your copy send $10.95 WPTPUBLICATIONS plus $2.75 shipping to Electronic Tech- 979 Young Street nology Today Inc., P.O. Box 240, Mas- Woodburn, OR 97071 sapequa Park, NY 11762-0240 Phone (503) 981-6122 CIRCLE 187 ON FREE INFORMATION CARO LINEAR IC EQUIVALENTS CALL NOW & PIN CONNECTIONS # it Linear IC Equivalents AND and Pin Connections RESERVE YOUR SPACE

HANDHELD GENERATOR/TESTER 6 x rate $800.00 per each insertion. KITS Function Gen.1HZto 300KHZ Reaches 245,824 readers. $79.95 Audio Gen. 8 steps 40HZ to 20KHZ Fast reader service cycle. $69.95 IF Gen. 455KHZ & 10.7MHZ, inter- Short lead time for the placement of 81141-Shows equivalents & pin con- nal modulation $59.95 Transistor Tester, ads. nections of a popular user -oriented Tests PNP, NPN $34.95 FM Gen. 80 to selection of European, American and 120MHZ, internal modulation $59.95 All Call 516-293-3000 to reserve space. Ask Japanese liner IC.'s 320 pages, 8 x 10 kits include test leads. Any kit assembled & for Arline Fishman. Limited number of inches. $12.50 Plus $2.75 shipping. tested add 25%. Send $1for complete pages available. Mail materials to: ELECTRONIC TECHNOLOGY TODAY catalog & coupon. SEL LABS, 22848 Engineering Admart, RADIO -ELEC- INC., PO Box 240, Massapequa Park, LEADWELL ST., CANOGA PARK, CA 91337. TRONICS, 500-B Bi-County Blvd., Farm- ingdale, NY 11735. New York 11762-0240. (818) 347-1960. CIRCLE 191 ON FREE INFORMATION CARD

SEMICONDUCTORS the signal generator to deliver a I -kHz I - amplified-and more noise is added-by volt signal. Next close S2 and adjust R1 the output drivers. The overall effect is continued from page 117 until the output drops to 0.5 volt. Open S2 called the Noise Factor (NF). and measure the resistance of RL-that's Noise is measured using the circuit nput resistance of the op -amp itself, its the op -amp's output impedance, Z0. shown in Fig. 9. In that circuit a diode value can be fairly large, especially when The measurement is valid because the noise generator is used to measure the the op -amp has a JFET or MOSFET in- impedance of the op -amp and that of the noise figure. With both switches in the put. The output resistor (R2) should have RC network behaves as a voltage divider, TEST positions, measure and note the out- a value that is equal to the output imped- and a voltage divider delivers half the put voltage on the AC voltmeter.Now ance of the op -amp. Now adjust the input input voltage only when the impedances place the switches in the CAL position and voltage for a small -signal output voltage of both legs are equal. increase the diode current until the meter from the test amplifier. Calculate PG reads the previous voltage level. using the formula shown in Fig. 7. Noise factor Then calculate the noise figure (in deci- Not all op -amp output is desirable, bels) as follows: Output impedance however. Some is noise that is generated NF = 10log 20 (IRs) Ideally, the output impedance of an op - in the op -amp's transistors. That noise is amp should be zero. In real circuits, not isolated to any particular part or area. where I is the diode current and Rs is the however, that's impossible. The actual In fact, it is a collective phenomenon. The source impedance. The accuracy of the output impedance may be measured using noise generated by the input transistors is technique depends on the accuracy of the the circuit shown in Fig. 8. First compen- amplified by the second stage, which adds 3 -dB attenuation pad and the diode's cur- sate for offset errors as before. Then set noise of its own. The total is in turn further rent source. R -E

130 MARKET CENTER

DESCRAMBLER catalog. All brands. Special com- OLDTtME radio programs on high quality tapes. FOR SALE bo Jerrold 400 and SB3 $165. Descrambler kit Comedy' Adventure! Music! Free catalog. CARL F. IS it true...Jeeps for S44 through the government? $39 00 (assembles in half hour). Send $1.00. MJ FROELICH, Heritage Farm, New Freedom. PA Call for facts! 1 (312) 742-1142. ext. 4673 INDUSTRY, Box 531, Bronx, NY 10461. 17349 TEST equipment, reconditioned. For sale. $1.25 for catalog. WALTER'S, 2697 Nickel, San Pablo. CA CLASSIFIED AD ORDER FORM 94806. (415) 724-0587. LASERS, components and accessories. Free cata- To run your own classified ad. put one word on each of the lines below and send this form along with your check to: log. M J. NEAL COMPANY, 6672 Mallard Ct., Ori- ent. OH 43146. Radio -Electronics Classified Ads, 500-B Bi-County Boulevard. Farmingdale, NY 11735 TUBES. new, unused. Send self-addressed, stamped envelope for list. FALA ELECTRONICS, Box PLEASE INDICATE in which category of classified advertising you wish your ad to appear. For 1376-2, Milwaukee. WI 53201 special headings, there is a surcharge of $23.00. ( ) Plans Kits ( ) Business Opportunities ( ) For Sale PHOTOFACT folders, under #1400 $3.00. Others S5.00. Postpaid. LOEB, 414 Chestnut Lane. East ( ) Education/Instruction ( ) Wanted ( ) Satellite Television Meadow, NY 11554. ( ) TI -99/4A software hardware bargains. Hard to find Special Category: $23.00 items. Huge selection. Fast service. Free catalog. DYNA, Box 690. Hicksville, NY 11801. PLEASE PRINT EACH WORD SEPARATELY, IN BLOCK LETTERS. COMMODORE chips, distributor, factory fresh (e.g. (No refunds or credits for typesetting errors can be made unless you clearly print or type your 6526-89.95 and many others). C64 power supply- copy.) Rates indicated are for standard style classified ads only. See below for additional $27.95...."Commodore Diagnostician", a com- charges for special ads. Minimum: 15 words. plete chart for diagnosing faulty IC's $6.95 pp. Send for complete chips parts catalog. Com- modore repair, 72 hour service, low prices (eg. C64 -S39.95). KASARA MICROSYS, INC., 33 Murray Hill Drive. Spring Valley, NY 10977. (800) 1 2 3 4 5 642-7634 (outside NY) or (914) 356-3131. APEX screwdriving bits. Any size. Complimentary illustrated list. R. SHOCKEY'S, 5841 Longford. 6 7 8 9 10 Dayton, OH 45424. (513) 236-2983. MICROWAVE antennas, multi -channel 1.9-2.7 ghz. DUAL POLARITY Now only $49.95. Oldest and 11 12 13 14 15($42.75) largest manufacturer. STAR ELECTRONICS CORP., Call 1-800-247-1151 or 1 (602) 939-1151. FLASHLIGHT that needs no batteries measures 5' x 3' ideal for every situation money back guarantee 16($45.60) 17($48.45) 18($51.30) 19($54.15) 20($57.00) $10.-SAMUELS ENTERPRIZES, 724 East 231 Street. Bronx, NY 10466. HACKING, crashing, pirating, and phreaking. Who's 21($59.85) 22($62.70) 23($65.55) 24($68.40) 25($71.25) doing it, why they're doing it, and how they're doing it. Sample programs, phone numbers, and the tools of the trade. Hacker's Handbook, $12.95. Com- puter Underground, $14.95. $1 postage to 26($74.10) 27($76.95) 28($79.80) 29($82.65) 30($85.50) CABLETRONICS, Box 30502R, Bethesda. MD 20814.

31 ($88.35) 32 ($91.10) 33 ($94.05) 34 ($96.90) 35 ($99.75)

We accept MasterCard and Visa for payment of orders. If you wish to use your credit card to pay for your ad fill CB RADIO OWNERS! in the following additional information (Sorry, no telephone orders can be accepted.): We specialize in a wide variety of technical informa:ion, parts and services for CB radios. 10M - FM conversions, repairs, books, plans, kits, high-performance accessories. Our 11th year! Catalog $2. Card Number Expiration Date CBC INTERNATI NAL, P.. B X 31500RE. PHOENIX, AZ 85046

RESTRICTED technical information: Electronic Please Print Name Signature surveillance. schematics. locksmithing, covert sci- ences. hacking, etc. Huge selection. Free brochure MENTOR -Z. 135-53 No. Blvd.. Flushing, NY 11354. IF YOU USE A BOX NUMBER YOU MUST INCLUDE YOUR PERMANENT ADDRESS AND PHONE NUMBER FOR OUR FILES. ADS SUBMITTED WITHOUT THIS INFORMATION WILL NOT BE ACCEPTED. TV tunable notch filters, free brochure. D.K. VIDEO, Box 63 6025. Margate, FL 33063. (305) 752-9202. CLASSIFIED COMMERCIAL RATE: (for firms or individuals offering commercial products or services) $2.85 per word prepaid (no charge for zip code)...MINIMUM 15 WORDS. 5°° discount for same ad in 6 TUBES "Oldest." "Latest." Parts and schematics. issues; 10% discount for same ad in 12 issues within one year: if prepaid. NON-COMMERCIAL RATE: (for SASE for list. STEINMETZ, 7519 Maplewood Ave., individuals who want to buy or sell a personal item) $2.30 per word, prepaid.... no minimum. ONLY FIRST RE Hammond. IN 46324. WORD AND NAME set in bold caps at no extra charge. Additional bold face (not available as all caps) 50c per word additional (20% premium). Entire ad in boldface, add 20% premium to total price. TINT SURVEILLANCE -counter, security. 52 prod- SCREEN BEHIND ENTIRE AD: add 25% premium to total price. TINT SCREEN BEHIND ENTIRE AD ucts -bulletproof to wireless! Catalog $2.00: PLUS ALL BOLD FACE AD: add 45% premium to total price. EXPANDED TYPE AD: $4.30 per word SPYPRO-045ER, POB 45521, Seattle, WA prepaid. All other items same as for STANDARD COMMERCIAL RATE. TINT SCREEN BEHIND ENTIRE 98145-0521. EXPANDED TYPE AD: add 25% premium to total price. TINT SCREEN BEHIND ENTIRE EXPANDED AIDS? Yes we have! Cable aids to help you. Zenith,

TYPE AD PLUS ALL BOLD FACE AD: add 45% premium to total price. DISPLAY ADS: I 2' - Jerro d. Scientific Atlanta. Oak, much more. No

$320.00: 2- 2' i--$640.00: 3 2'I. -$960.00 General Information: Frequency rates and prepay- Michigan sales' HOTRONICS, (313) 283-4299. ment discounts are available ALL COPY SUBJECT TO PUBLISHERS APPROVAL. ADVERTISEMENTS USING P.O. BOX ADDRESS WILL NOT BE ACCEPTED UNTIL ADVERTISER SUPPLIES PUBLISHER CABLE TV equipment. All major brands. Spe- WITH PERMANENT ADDRESS AND PHONE NUMBER. Copy to be in our hands on the 12th of the third cializing in Scientific Atlanta, Jerrold. and month preceding the date of the issue. (i.e., Sept. issue copy must be eeceived by May 12th). When normal Zenith, add-ons. Our units have worked where closing date falls on Saturday, Sunday or Holiday, issue closes on preceding working day. others have failed. Send $2.00 for catalog to K.D. VIDEO. P.O. Box 29538, Minneapolis. MN 55429 131 TUBES 59e. Year Guarantee. Free catalog. Tube tester $8.95. CORNELL, 4215 University, San Di- ego. CA 92105. SURPLUS auction, bid kit $1.00, ends 1121 87. Reserve your 1988 parts catalog. LYNBAR INDUS- TRIES, 205 Main, Box 822, St. Joseph, MI 49085-0822. CUSTOM front panel nameplates for your projects. For details: J & E ENTERPRISES, 2457 N. Mar- mora. Chicago. IL 60639. ASSORTMENT #103, (February '84 article) REMOVES VOCALS FROM RECORDS' printed circuit, toko coils, transistors. IC's, di- Now You can sing with the world's best bands! odes. power supply, 525.00. Five $112.50. Ship- The Thompson Vocal Eliminator can remove ping $3.00. JIM RHODES INC., P.O. Box 3421, most or virtually all of a lead vocal from a standard Bristol, TN 37625. stereo record and leave the background! CABLE TV converters. "NEW" Zenith flash, Scien- Write or call for a free brochure and demo record. tific Atlanta. Jerrold. Oak, Zenith. Hamlin. Many LT Sound, Dept. R-1,P.O. Box 338, others. "New" video hopper "The Copy Killer". Stone Mountain, GA 30086 404 493-1258 Visa, M/C & Amex 1 (800) 826-7623. B&B Inc., 10517 Upton Circle. Bloomington, MN 55431. GIANT shortwave listener's catalog. Features PLANS AND KITS shortwave receivers, antennas, accessories, radio HI -Fl speaker systems, kits and speaker compo- teletype, facsimile equipment and books. Free! UNI- nents from the world's finest manufacturers. For VERSAL SHORTWAVE RADIO, 1280 Aida Drive, #RE, Reynoldsburg, OH 43068. beginners and audiophiles. Free literature. A&S SPEAKERS, Box 7462. Denver, CO 80207. (303) CAD-Visionics EE01 for PC's $800.00 or best offer 399-8609. (402) 346-6272. 809 So. 35th Avenue, Omaha, NE VOICE disguisers! FM bugs! Telephone transmit- 68105. ters! Phone snoops! More! Catalog $1.00 (Refunda- MANUFACTURE electronic equipment in your ble): XANDI ELECTRONICS, Box 25647. Dept. home for the Army, Navy, Air Force, and NASA. Will 60T, Tempe. AZ 85282. supply plan. Inexpensive easy to build equipment. STRANGE stuff. Plans, kits, new items. Build satel- Government pays $4,000. Cost you $900. Profit lite dish $69.00. Descramblers, bugs. adult toys. $3.100. Send $10 to SUBCONTRACT R & D, Informational photo package $3.00 refundable. DI- LIQUIDATION 136-31 222nd St., Laurelton, NY 11413. Attention: Wilner Nau. RIJO CORPORATION, Box 212, Lowell, NC 28098. PRICE OAK 56 channel wireless remote converter de - scrambler, original refurbished equipment, exceptional video, $175.00; legal to own your equipment, however, Federal law prohibits hookup without cable FINALLY! company permission. PONDEROSA. (303) An interesting and worth- 661-1659. (We ship C.O.D.)! while project. This EASY - TO -BUILD circuit lets you $499 FREE remote control converter with any de - use any regular TV set as INCLUDES scrambler below: Oak VN12 $85.00: new Hamlin a simple OSCILLOSCOPE. MLD1200 $90.00: new SB3 $89.00; new Trimode DETAILED PLANS: S4.95Build for less than $10. Bistate $125.00; Starcom-6 system $125.00; Zenith NO MODIFICATIONSTO TV! 1. LASER -(10 milliwatt) cable $175.00: legal to own your equipment, TV -SCOPE Single or dual trace. PENN RESEARCH, Boa 3913 2. LASER Power Supply however, Federal law prohibits hookup without cable Send for FREE CATALOG of company permission. PONDERSA. (303) Williamsport, PA 17701 other plans and kits. 3. MIRRORS (5) 661-1659. (We ship C.O.D.)! 4. LENSES (3) TUBES, $2.49, TV. audio. Special, 2000 types. 5. BEAM SPLITTERS (2) DESCRAMBLING, New secret manual. Build your SASE brings lists. DMF, 6690 7 Mile, S. Lyon, MI own descramblers for Cable and Subscription TV. 6. POLYGON MOTOR. LENS 8 DRIVER 48178. Instructions. schematics for SSAVI, gated sync. 7. A-0 MODULATOR sinewave. (HBO. Cinemax. Showtime. etc.) $8.95 RADIO tubes, parts. Unused. Original cartons. + $1.00 postage. CABLETRONICS, Box 30502R, A-0 DRIVER Send $1.00 (refundable) for lists. DIERS, 4276-E2 Bethesda. MD 20814. North 50 Street, Milwaukee, WI 53216-1313. 8. LASER BRACKETS (2) SATELLITE descrambling manual, Video Cypher 9. SENSOR (2) II. Schematics, thorough explanation of digital audio SEMICONDUCTOR and transmitting tube. quota- encoding, EPROM code. DES. (HBO. Cinemax, tion sent on request. TSUTOM YOSHIHARA, Showtime.) $10.95 +$1.00 postage. ITEMS MAY BE C1-105 Deguchicho-34, Suita. Osaka 564. Japan. CABLETRONICS, Box 30502R, Bethesda, MD PURCHASED SEPARATELY 20814. QUANTITIES LIMITED NEW 30 channel microwave TV antenna -com- PROJECTION TV...Convert your TV to project 7 plete $149.95. Standard 2 channel $99.95. Lifetime foot picture. Results comparable to $2,500 proj- warranty -dealer pricing-C.O.D.-MC-VISA- ectors. Total cost less than $30.00. Plans and 8" CALL FOR FREE HIGH-TECH ELECTRONICS, 337 Vineyard Ave., lens $21.95. Illustrated information free. MAC- Suite 300, Ontario, CA 91764. (714) 391-1655. ROCOMA-GC, Washington Crossing, PA 18977. INFORMATION Creditcard orders 24hrs. (215) 736-3979. TUBES, name brands,new, 80% off list. KIRBY, 298 DESCRAMBLING! Latest information packed man- ABOUT THIS West Carmel Drive, Carmel, IN 46032. ual! All systems. Schematics, theory, turnon's, countermeasures, $14.95. C.O.D.'S RETZ, 4021 Gilbert. AMAZING PICTURE flyer lists quality surplus electronics at Dallas. TX 75219. (214) 528-0309. low prices. Since 1970. Send for the last 3 issues. CATALOG: hobby/broadcasting/1750 meters/ham/ STAR-TRONICS, Box 683, McMinnville, OR 97128. CB: transmitters, antennas. scramblers, bugging LASER DECK ADD 5 important features to your home tele- devices, more! PANAXIS, Box 130-F11, Paradise, CA 95967. CONTINENTAL U.S A phone. SASE (805) 583-4272. B&M ENGINEER- ING, Box 823. Simi Valley, CA 93062 CRYSTAL radio sets, plans, parts, kits, catalog (800) 872-8878 CABLE TV equipment S.A.. Jerrold, Zenith. $1.00. MIDCO, 660 North Dixie Highway, Hol- Hamlin. Oak, Eagle. filters, remotes and more. lywood, FL 33020. Best prices C.O.D.'s accepted. dealers needed. DECODING plans and theory booklets. Video tape INSIDE CALIFORNIA Ours work where others failed and we gaurantee copy protection, removes flashing and jitter. 30 (800) 223-9977 it! TRANS -WORLD CABLE CO., (218) 543-6671. pages, $15.45. Jerrold DI and DIC decoder theory, PLASMA sphere fascinating lightning display. Build 12 pages, $6.95. Gated pulse decoding plus new TIME universal single level suppression decoder, works L.A. AREA & TECH. INFO. 5" unit for $50, plans $10, prefilled sphere parts kits $50, complete units, catalog $2. RIESS, P.O. Box on Hamlin. Jerrold, Sylvania, Eagle. 39 pages, 54625, Dept. E, Phoenix, AZ 85078. $15.00. Video scrambling techniques, the original LINE (213) 217-8912 secret manual, sinewave and Zenith SSAVI, 57 SCRAMBLING news. Monthly. No advertisers to pages, $14.95. Hidden signals on satellite TV. 178 1490 W. ARTESIA BLVD. protect, no products to push and no axe to grind. pages, $16.95. P.C. board and kits available. GARDENA, CA 90247 Unique, interesting, informative SHOJIKI, 1327R ELEPHANT ELECTRONICS INC., P.O. Box 41865- Niagara St., Niagara, NY 14303. J, Phoenix, AZ 85080. (602) 581-1973. CIRCLE 220 ON FREE INFORMATION CARD 132 DO YOU REALLY GET THE BEST BUY FROM THEM? Let's face it: There will always be some outfit that can undercut a published price. They do it by having no overhead, and no responsibility tc you, the consumer. "So, you want that Jerrold 450 combo? The one that PICNIC CON Co.. NC.. is offering for s19900? Well, that's a good price, but -tere's what I'll do..." What may happen is that you may save a couple of bucks at the time. But suppose there's a problem. (and it happens to the best of them,) and you call that "Dealer"... This could be what you'll hear: "No, Steve isn't here. He moved out, the bum! And he owes me 43700 on the phone bill! No, Idon't know about any guarantees on your Gerald, who's that? Listen, if you see that ceep..." etc. At Pacific Cable Co., you've got an established company who will be here for you, time after time. We may be tough competitors, but we've got a soft spot for our clients! Try us, and be treated right -and we'll prove it by giving a one-year warranty on everything wesell. Check our prices on Scientific Atlanta Units!

1 10 OR 1 ITEM ITEM 10 OR UNIT MORE UNIT MORE RCA 36 Channel Converter (CS 3 output only) 29.00 1800 Minicode (N-121 89 00 58.00 Panasonic Wireless Converter (our best buy) Imo 6900 Minicode (N-12) with Van Sync 9900 62.00 400 or 450 Converter (manual fine tune) 88.00 69.00 *Minicode VariSy-rc with Auto On -Off 145.00 105.00 *Jerrold 400 Combo 16900 119.00 Econocode (mmicode substitute) 79.00 52.00 Jerrold 400 Hand Remote Control 29.00 18.00 Econocode with VanSync 8900 56.00 *Jerrold 450 Combo 199.00 139.00 MLI3-1200-3 (Ch.3 output) 9900 5800 *Jerrold 450 Hand Remote Control 2900 18.00 MLD-1200-2 (Ch.2 output) 99.00 5000 Jerrold SB-Add-On 89.00 58.00 `Zenith SSAVI Cable Ready 17500 125.00 *Jerrold SB-Add-On with Trimode 9900 70.00 Interference Filters (Ch.3 only) 24.00 14.03 M-35 B Combo unit (Ch .3 output only) 99.00 70 00 Eagle PD -3 Descrambler (Ch .3 output only) 119.00 65.00 M-35 B Combo unit with VariSync 109.00 75 00 'Scientific Atlanta Add-on Replacement Descrambler 119.00 7500

Quantity Item Output Price TOTAL CHECK US OUT -WE'LL Channel Each PRICE MEET OR BEAT THE OTHER'S ADVERTISED WHOLESALE OR RETAIL PRICES!

'MasterCard VISA SUBTOTAL California Penal Code #593-D forbids us trom Shipping Add shipping any cable descrambling unit to anyone not, per unit residing in the state of California. COD & Credit Prices subject to change without notice Cards -Add 5% Pacific Cable Co., inc. PLEASE PRINT TOTAL 73251/2 Reseda Blvd., Dept. R-11 Name Reseda, CA 91335 Address City (818) 716-5914 (818) 716-5140 State Zip Phone Number ( O Cashiers Check C Money Order COD C Visa 0 Mastercard NO COLLECT CALLS! Acct Exp. Date IMPORTANT When ordering, please have Signature the make and model number of the equipment FOR OUR RECORDS used in your area -Thank you! DECLARATION OF AUTHORIZED USE - I, the undersigned, do hereby declare under penalty of perjury *Call for availability that all products purchased, now and in the future, will only be used on cable TV systems with proper authorization from local officials or cable company officials in accordance with all applicable federal and Prices subject to change without notice state laws.

Jerrold is a rag stared trademark of General Instruments Corp Dated Signed

133 ELIMINATE light and dark from copying new video REMOTE CONTROL KEYCHAIN tapes. Completed and tested units $75.00. Sche- Multi -Channel Microwave T.V. Receivers 1 9-2 7 GHz Parabolic Dish 40- dB Gain Complete w/mini-transceiver matic $5.95 circuit board $5.00. BLEDSOE, PO. and +3-15vdc receiver Box 3892. Central Point, OR 97502. LIFETIME WARRANTY Fully assembled including plans Complete System $89.95 (Shipping Incl.) to build your own auto alarm SOFTWARE!!! Make copies of protected software. Dealer Rates. Replacement Components Machine costs under $100. Saves you hundreds. Expert Repairs Available $14.95Ch edcaks; sV ri set or nr M / C even thousands! Send $3.00 for complete informa- K & S ELECTRONICS Call now for same tion. MIKE McGLINCHY, 214 Verano Dr.. Los Altos, P.O. BOX 34522 day 01 I VISITECT INC (415) 872-0128 CA 94022. PHOENIX. AZ 85067 16021e I PO BOX 5442, SO. SAN FRAN. , CA 94080 VISA/MC/C00 S2 credit on phone orders,

P.O. Box 1111-E FREE microprocessors. memory chips, etc. Free r NUTS & VOLTSPlacentia, GA 92670 electronics magazine subscriptions. Free education MAGA 714 632 7721

3.S SY.S1 spasm SATELLITE TV in computers. For information write MICROSAT GIVE YOURSELF A BREAK -A PRICEBREAK! 4tlem Mal -LOA CORPORATION, 2401 N.E. Cornell, Bldg. 133, Mail aer roSlo oo NUTS a VOLTS WILL Sad YOU MONEY Too v.... SI. o0 SATELLITE TV equipment. Buyers guide. discount Stop 125. Hillsboro, OR 97124. ON ELECTRONIC PARTS EQUIPMENT prices 52 00 N.E.C.S. INC., Box 22808-R4. Little Plan SHOW YOU WHERE TO FIND UNIQUE, 1 Oro II. Rock. AR 72221. VIDEOCIPHER II manual 119 pages -$27.45 Oak UNUSUAL AND HARESTO FIND ITEMS. Orionmanual 120 pages -$22.45 Macrovision SUBSCRIBE TODAY! Are Mil DESCRAMBLER. Build our low cost satellite TV Iv. $5o.4 "Stabilizer" -$99.95 Plans-kits-descrambling video only descrambler for all major movies and books. Catalog -$2.00. MICROTRONICS, Box A Iletionel Publintien For The Buying And Selling Oalectrenie *Owl sports. Uses all Radio Shack parts. Order P.C. 6426, Yuma, AZ 85364-0840. board and instructions by sending check. money PLANS. Plasma display, H.V. generator, CB modu- order, or Visa for S35.00 U.S. funds to: VALLEY lator. Linear amplifiers, Painfield generators. shock MICROWAVE ELECTRONICS, Bear River. Nova FREE catalog 99 -cent kits -audio, video, TV, com- Scotia. Canada, BOX -1B°. (902) 467-3577. sensor. Plans for all $20.00 complete. AET, Suite puter parts. ALLKIT, 434 W. 4th St.. West Islip. NY 173. 5800-A. North Sharon, Amity Rd., Charlotte. 11795. NC 28215. DETECTIVES, experimenters. Exciting new plans. NOVELTY type electronics projects for the Hard to find micro and restricted devices. Large "'SCRAMBLING NEWS " gadgeteer. Weird, unusual, fascinating and fun. catalog $5.00, refundable on 1st order. WILSON, PAY TV AND SATELLITE DESCRAMBLING Free information. TAYLOR ELECTRONICS, P.O. P.O. Box 5264, Augusta. GA 30906. Schematics theory bypasses. 13 cable. 7 satellite New SA turn - Box 1612, Destin, FL 32541. on. MLD-1200-3 514 95 Experiments With Vid mmumsketeeHring $14 95 Cable TV Security. design512 95 M BUILD this five -digit panel meter and square -wave k Microwave hacking $9 95 BuildIlit generator including an ohms, capacitance and tem Immix* $12 95 Any 3 527 ScramblingNewsMonthly frequency meter. Detailed instructions $2.50. eature artic es. product reviews law history patents 524 95 yr BAGNALL ELECTRONICS, 179 May, Fairfield. CT VIDEO TAPE Sample $5 Winter catalog Sr 06430. Shook' Electronics Corp 1327A Niagara St IN; COPYGUARD Niagara Falls. NY 14303 CODs 716-284-2163 UNIVERSAL eight voltage regulated power supply. Will power 99°4 of all discrete transistor and inte- Eliminate the latest copyguard problems grated circuit devices. Handiest DC supply around. units from $5995 to $16995 Every electronic workshop should have one. Kit SATELLITE TV receiver kits! LNAS! Instructions, without case $179.95. Complete kit $239.95. Wired 'Deluxe Etectronics (714)998 -6,56t; Schematics! Catalog $1.00 (refundable): XANDI $449.95. F.O.B. PEPPERKIT, 527 -10th Street, 1432 Meim Wy.,Oran,gr, Ca. 92665 ELECTRONICS, Box 25647. Dept. 21X, Tempe. AZ Sparks. NV 89431-0811 85282

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LATEST DESIGN PROGRAMS UP TO 4 DEVICES AT ONE TIME FEATURES EASY Call or write today for your free TO USE MENU DRIVEN SOFTWARE THAT RUNS UNDER PC OR MS-DOS. USES AN IL2111;1 catalog containing speakers, semi - INTELLIGENT PROGRAMMING ALGORITHM FOR SUPER FAST (8X) EPROM BURNING. THIS PLUG-IN BOARD ATTACHES TO AN EXTERNAL MINI CHASSIS 2 -Way 30 watt conductors. CATV products, tools. 4. 1/280-190 S395 CONTAINING 4 TEXTOOL Z.I.F.SOCKETS. NO PERSONALITY MODULES ci) hardware, TV -VCR parts, and ILi REQUIRED AUTOMATIC VPP SELECTION: 12.5V, 21V, OR 25V EPROM DATA CAN 3 -Way 60 watt t. ALSO BE LOADED FROM OR SAVED TO A DISKETTE. PROGRAMMING SOFTWARE .260-200 $750 more. .j 2 SUPPORTS: 2716, 2732, 2732A, 2764, 2764A. 27128, 27128A, 27256, 27256A. 27512, AND ' Way 100 wall iLe 27512A. ASSEMBLED AND TESTED, BURNED. IN WITH MANUAL. $169 WITH O SOFTWARE. cc 1260-210 S1250 I- JUST RECEIVED SAME AS ABOVE PROGRAMMER, BUT PROGRAMS 10 UNITS AT 0 ONE TIME - $299 LU r CALL TOLL FREE 15 day money beck eueraniee. S10.00 minimum order COD olden accepted. 24 hour shipping. VISA' Digital Research Computers O 1-800-255-3525 Shipping chargeUPS chart rate(52.50 men- imum charge) Hours 5:30 a.m. -6 p.m. EST ME rl Ohio: 1-800-322-3525 P.O. BOX 381450 DUNCANVILLE, TX 75138 (214) 225-2309 PARTS EXPRESS INTLINC. MasterCard cr Local: (513) 222-0173 340 East First SI Dayton Ohio 45402 TERMS: Add $3.00 postage. We pay balance. Orders under 615 add 754 handling. No C.O.D. We accept Visa and MasterCard. Texas Res. add 6-1/4% Tax. Foreign orders (except Canada) add 20% P 8 H. Orders over $50 add 856 for insurance. 134 CIRCLE 203 ON FREE INFORMATION CARD TELEASE-MAST assortment #301 (October '86 WANTED excess inventories of I.C.s. d sk drives. article) printed circuit, IC's, transistors, diodes. circuit boards. computers, etc WESTERN TECH, BUSINESS OPPORTUNITIES $25.00. Shipping $3.00. JIM RHODES, INC., P.O. (818) 882-1355. (CAL.) MAIL-ORDER money pours in daily!I make it. so Box 3421. Bristol, TN 37625. can you. Full details $10. postpaid. SERENDIPITY, 675 Conklin Street. 1-B. Farmingdale, NY 11735 CABLE TV Secrets -the outlaw publication the cable companies tried to ban. HBO. Movie Channel. YOUR own radio station! AM. FM. cable. Licensed Showtime, descramblers, converters. etc. Sup- TUBES - 2000 TYPES or unlicensed. BROADCASTING, Box 130-F11. pliers list included $8.95. CABLE FACTS. Box 711- Paradise, CA 95967. R. Pataskala. OH 43062. DISCOUNT PRICES! Early, hard -to -find, and modern tubes EARN thousands with your own part time elec- Also transformers, capacitors and tronics business.I do. Free proof, information. IN- parts for tube equipment. Send $2.00 DUSTRY, Box 531, Bronx, NY 10461. Cable Converters & Decoders for 20 page wholesale catalog. 1 10 'Jerrold S.B. Add On $89.00 $58.00 ANTIQUE ELECTRONIC SUPPLY 688 W. First St.Tempe. AZ 85281.602/894-9503 'Jerrold Tri-Bi Add On $98.00 $78.00 BIG ELECTRONIC Jerrold Starcom CSV $139.95 Call pROFITS MTS Converter + Remote $85.00 $69.00 ASSEMBLY BUSINESS Jerrold 450 DRZ-3A $95.00 $79.00 Start home spare time Investment knowledge or Parental Control MTS Plus $100.00 $85.00 INVENTORS experience unnecessary BIG DEMAND assem- Hamlin MLD 1200-3 $98.00 $58.00 bling e.ectronic devices. Sales handled by profes- INVENTORS! Can you patent and profit from your sionals Unusual business opportunity. Scientific Atlanta Add On $140.00 $99.00 idea" Call AMERICAN INVENTORS CORPORA- FREE: Complete illustrated literature M-35 B Cornbo With VariSync $99.00 $69.00 TION for free information. Over a decade of service. Mini Code N-12 VariSync BARTA. RE -O Box 248 $99.00 $58.00 1-(800) 338-5656. In Massachusetts or Canada call Walnut Creek Calif 94597 442 VariSync (N-12 Substitute) $89.00 $58.00 (413) 568-3753. Wireless Video Sender $45.00 Call 'S.B. TRI-BI Flash.ng Got You Down? Try original Jerrold Equipment ft might just solve your problems. Call or write PROJECTION TV...Make $$$S assembling proi- for Free Catalog. All products Guaranteed 90 days plus. DESCRAMBLER MODULE ectos...easy...results comparable to $2,500 pros- M.D. Electronics 5078 So. 108th Suite 115 ectors. Total cost less than $30.00. Plans, 8" lens Omaha NE. 68137 Phone (402) 554-0417 COMPLETE cable -TV decoder in a mini -module. and dealers information $20.50. Illustrated informa- Latest technology upgrade for Jerrold 93-3 or Ra- tion free. MACROCOMA-GCX, Washington Cross- dio -Electronics Feb. 1984 project Available at very - ing. PA 18977. Creditcard orders 24hrs. (215) low cost. For literature. SOUTHTECH DISTRIBUT- 736-2860. WANTED ING. (813) 222-3293. DEALERS wanted. Notch filters for any channel. INVENTORS! AIM wants -ideas. inventions. new Send for further information or $15 for sample unit products, improvements on existing products. We (specify output channel of converter). DB ELEC- present ideas to manufacturers. Confidentiality THIS IS AN EXPANDED -TYPE AD WITH A TRONICS, P.O. Box 8644. Pembroke Pines. FL guaranteed. Call toll free 1-(800) 225-5800 for infor- TINT SCREEN. See how it jumps out on the 33084. mation kit. page. To order your ad in this format calcu- HOME assembly. Assemble PC boards for video INVENTIONS, ideas, new products wanted! Indus- late the cost at $4.30 per word for the ex- accesories. We supply materials. No experience try presentation national exposition. Call free needed $7.50 per hour. Send self-addressed 1-(800) 288 -IDEA. Canada. 1-(800) 528-6060 panded -type and add 25% for the tint stamped envelope, to: MICRON -ELECTRONICS. X831 background. Box 47'6 Akron, OH 44310

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CA 92106-8369 __-1-'11-.2- McGEE'S SPEAKER & ELECTRONICS CATALOG FISHER 1001 BARGAINS INSPEAKERS TELEPHONE VOICE toll free 1-800-346- 2433 for ordering only. SCRAMBLERS 1901 MCGEE STREET KANSAS CITY, MO 64108 FISHER SCRAMBLE your telephone conversations. Authorized Parts Distributor Fully self-contained voice privacy system that pre- for Exact Original Parts In vents unauthorized interceptions. Highly recommended for Cellular and I.M.T.S. telephones. Call- SANYO N.A.S. (213) 631-3552. SCIENTIFIC ATLANTA & SB-3 SCIENTIFIC Atlanta models 8500-8550. remote SYLVANIA Cable TV Converters included...5240.00. SB-3's...$74.00. TRI- SBSA-3's...$99.00. Zenith (Z-Tac) PHILCO (NAP) Why Pay A High Monthly Fee? descramblers...$169.00. N-12 (Vah-sync)...$89.00 Jerrold Products include "ew Jerro I M-35 B (Van-sync)...$99.00. Jerrold -450 and 550 - PANASONIC Meg converters...$95.00. Dealer discount on (51 QUASAR (MECO) Tri-Mode," SB-3, Hamlin, Oak VN-12, units. Brochure available. Call...N.A.S., (213) M -35-B, Zenith, Magnavox, Scientific 631-3552 G.E. Atlanta, and more. (Quantity dis- R.C.A. counts) 60 day warranty. For fast service C.O.D. orders accepted. Send THIS IS A BOLDFACE EXPANDED AD. If you Stocking Large Inventories SASE (60 cents postage) or call for info like this format, request it. Your cost is Fastest Service (312) 658-5320. Midwest Electronics, S4.30 per word, plus 45% for the boldface For Orders Only Call Inc.!, HIGGINS ELECTRONICS, 5143-R and tint background. 1-800-874-1765 W. Diversey, Chicago, IL 60639. MCi Nat'l Visa orders accepted. No Illinois orders 1-800-874-1764 accepted. Mon. -Fri. -9 A.M.-6 P.M.CST Copies of articles from this N.Y. Only publication are now available from For ALL Other Inquiries Call MASTERCARD AND VISA are now accepted the UMIArticle Clearinghouse. 516-585-8111 Mail to Universits. Microfilms International for payment of your advertising. Simply 300 North Zeeb Road. 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136 Plug a Friend into Radio -Electronics this Christmas...and Save $12!

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MAN6910 - Double Digit 7 Segment Display, Hi 50 PIN IDC Ribbon Cable Connector so Efficiency Red 5" Comm Ann 125 36 PIN R1 Angle -Snap OM" Header 005487 - 14 Segment Driver Chip 75 til PIN Header for Ribbon Cable 3/51 ICAO Wevis .,:n4r.aitv71,/ Hewlett Packard ]Sag 4" Red Ann7651 9, 7 PIN Male Header AA 2041 7 Seg 3" Bent Lead (Hobby Grade) 4/$1 (201) 894-8008 IC Storage "Bug" Box $2 45 7 Seg 6" Bent Lead (Hobby Grade) 3/$1 1 5A 501/ Bodge (105) Heavy Duty Alligator Class (10 Sete) $2 30 0.-----) 50 Regular Alligator Clips (10 SrSI 130 AfIT 4A 500 Bridge (KBUO5) 75 50,510 6A 600V Bridge 5/8" Square Woe Strippers (Spring Loaded. Adjust I $2 50 I 00 5" Needle Nose Pliers (Spring Leaded) $3 95 10A 500V Bridge 5/8' Square 1.15 ihEAF1 TRANSISTORS 4 1/2' Diagonal Cutters (Spring Loaded) 13 95 . '.9iA 200 Bridge (Solder Lug Type) 2.00 TIL SERIES 7.07 60 '4'''.4 .5 ."'" & 01001$ Nut Driver set for 3/16". 1/4', 5/16" 3/132 .475.65 70 WM 25 -MC SPST Reed Relay PC Mount I' AOC , 60 OS MOP. Jeweler's ScrewdriverS 14 pcs) 705° ' - 7.5173 45 W15 30 , i PB Switch (Keyboard Type) $2.65 /4)03 t 00 ..12225 34, .4.5. 74 30 40. n Desoldering Pump (So4der Sucker) $4.00 mor 75 75'.7. "C'35° M2220 a 1 ' Toggle DPDT (Lock Latch Feature) 741.519, 45 4019 30 o. 5,3 ' ' 75 Replacement Tips Mr Solder Sucker . ' ' 2/$300 14. n 6.42.3074 r . '..''ursier 6 40,2 W '. wine Snap In- Rocker wiM Bulb Socket 95 25W Precision Scattering ,ron T5 '''''555 " 2.420546 35.00 ...... 55 7.51. 60 4023 -. ' .N22153 t SO 20 , ,00000 tea, 30 .n Lighted Switch (No Bulb) 08 - Moor - 45 Safety Goggles oN. ..74.51. 60 $2.95 4024 45 nsr on .124 SO ,t5hOutton ()PST Off - Morn PC Mount 341 DeSoldering Braid (5 Foot Roil) 741.522. TO 1.21304 SO ,,,,, 99 74w 63 NeT26 75 . QM ,,,,,... OPDT Push Button 6A I25V 7.5240 05 4MS 60 5. 7.7C7605 45 65 Solder Aid Tool Kil (4 pcs) MO 30 ON 3906 . DO r 53.00 4. 60 .1040 60 - to .5 .7636 45 TPDT -Bat- Handle Toggle iOn OM On) 1 65 rare a, 711.1 WKS ',.. 25137.96 2 SO Model 6106 Logic Probe (Pencil Type) $18.95 .40. M 741, M 747500 -'' '5 ."°.'T .5 /75 DPDT RI Angle PC TOggle (On OR On) 95 Model 6208 Logic Pulser (Pencil Type) TO 7475.744 5N 60 0.. MN 45 :Kline $18 95 7616 . 4042 SO 0000, o 11 LED Bar Graph Display 2-3/4", Rectangular LED's 25 7.50, ' 63 ,,,,B45 ... op tr. 35 1.7905 45 OluF 100V Mylar Cap 20/91 /00 25 7.502 20 74)S247 1 90 4047 ...7912 45 1092 .6774 TS, (Specify Red. Green Amber) 269 luF 200V Mylar Cap F425 . 25 15/51 25 maw TO 747STS, Gant Alpha Numeric Display 11/2" x 2" 7 5135 Total) UM 30 7.504 40 .... " 'N.. 40, ',Mystery, Bag 61 The -OHM- Bag S 25 7.5.753 63 4050 25 Red LED Matrix 4.95 7427 25 741.50S an 7.5257 ..... M 'Mystery, Bag 2 The -Volt- Bag ren 25 7.5OG .B.' . N0104 22uf 350 Solid Tantalum (Kerne!) 311 00 ',Mystery, Bag 3 The -Circuit" Bag M 7475256 W 4052 60 , 74M 25 74503 Radial Lytics - luF 500 13. 2 2uF 50V 13, 3 3uF SCN 20 7.5259 05 ',Mystery, Bag 44 The "Frequency" Bag 31 /432 25 74.510 40. 50 TO PAL 5260 30 14, 4 7uF 400 12. tOuF 501/ 14 22uF 35V 15. 331/F to.43/ 25 7.5.5,, W .66 ',Mystery? Bag 5 TheTolerance- Bag SI 25 7.5262 40 .014 60 35V 15, 47uF 50V 15, 100uF 35V 20. 220uF 35V 22, No Returns or Exchanges with Mystery Bags n 7.572 25 / .75»6 W 4009 20 7430 25 7x.513 DIP IC SOCKETS 330uF 35V 33 4701/F 350 39, 1.000ut 16V 45 25741.52/3 45 40/0 en 9V Battery Snaps 7/51 7440 30 7.514 1.000uF 75V Axial /41.5263 75 20 8 PIN/ 09, 75 Sell Adhesive Rubber Stripping -- Cut to Any Lengths 1412 25 7.5.5 .7. 14 PIN/ 13. 16 PIN/ 15.18 PIN/ 17, 20 25 7.5203 T5 4072 3,200uF 500 Twist Lock 65 nes so 74)5.70 20 PIN/ 19, 22 PIN/ 21, 24 PIN/ 23. 28 PIN/ 26. 40 PIN/ 28 You Choose (3M-Bumpon). 3 Fee1P32. 10 Fee1/55 00. 20 /ewes n W73 3,3001/F 500 Axial Lytic 85 7.7 75 7452, 20 741.611 . Zero Insertion Test Socket 28 PIN 5.00 50 Feet/520 00 /450 W 4076 SO 5.000uF Computer Grade (Mallen/I 60 74/522 20 t 15 1.50 HI Reliabwly TO3 Socket lAugul) 745. P. ST99 407, T5 65 2, man TO 7.53.76 7, Ceramic Monolith,cs - All NOV or Higher Low Fluid Level Deleclor Kit - Pans, PC Board 8 riisx w 7 4)527 6376 . TOKO COILS FOR FEB 1984 20 /45365 55 Wei TO 3300, 47000. 00IuF. 0016uF. 0022uF, O027uF. Mslructwns 7.11 30 7.526 25 495 7475366 TV PROJECT 0033uF, 00390F ((All 3041) OluF -20/51, 02200 74M.1 AM 77520 .M. TO Soldering Iron Convenience Stands 5/51 00 50 74)5367 so Toko rats 45 7.530 .37.5 55 'sBKANiX5552AXY42). 0E520HN3000023 15/St.tuF 10/St 22uF 10/91 20 741.5366 35 4006 45 Voltage Male Swooning Regulator Kit $1895 I 46, es /41.512 ( On uH) 8 L-2t12uH) need t Set 014 pcs Woo 3 Sets Crystal Clock Oscillator 14 9760 MHZ 20 7475373 65 6093 45 50 50 COMMODORE COMPUTER KEYBOARD& MOTHER - b. 7.533 NO 5374 5 4160 51500. 10 Sets $4500 UCN41,6B - OSC/Freq Div Clock IC 5/100 ,es ss /.537 25 nisan weS OM Isolator 1-11160(Transislor Type) '65 AM/FM Radio IC w/Data Sheet (.2204) 15/51.00 COMBO. INCLUDES ARTICLE FOR COM- .466 40 7.538 . its 25 7.5377 70 .16 4, Opto Isolator HXXCX(SCR Type) 85 Slide Pols - 1 Each 50K. 100K. lio 45 7.540 30 1 2M 2M.5M - si PATIBILITY (INTERFACE) $12 95 74)53711 t M4.2. 45BOARDes Hewlett Packard Clock (No Specs) , es 7.542 30 2.50 74165 (Shift Register) House48095 10/S1 74)53. To .. ...5 5 7.57 90 .5 Line Cord 6 feel UL Listed SPT 2 60 ULN223I (Delco DM501 Dual Prearnp IC 475620 .5 2/1 MODEL 705 Digital Multimeter 7.551 20 7475650 as 4502 es Scope Probe Set w/Everything x1/x10 24.95 Switching Power Supply Pars 8 Minus ' - 5 8 12Votts 45 7.564 ?5 immulanuagunim 70 Woe Stand Offs 10/$1 200W by Convey 549 95 55 ?A SS5 30$45E SERIES awe to 35 741.573 Zener Asal - 65 pcs 10110 - Includes Minimum 3 MRF901 (Hobby - You Test) DC voltage 100in to WON M,oso,o, oo 4517 75 10/51 N . 7.574 Different 1W Devices Sr.95 Piher PTIOV 3/8' Horizontal Mount Trimpots 100 OHM. AC volt aga 103,v to MOB c ,. 745C,36 35 5 1. 745/5 30 55 DC Current 0 too to ICIA "..51 95 74SC139 35 Resistor Ass's - ',WO pcs 35 Values Minimum 1K, 5K, 10K. 20K. 506. 1006, 200K. 5006, IM 35 7.555 35 .5'5 5° AC Current 0111A to 106 745C237 eo .525 PopularValues(11(.10K.100KI Included Mostly 1/4 8, Single Turn ' 40 7.5713 40 " 4/SI 11 I co Resistance 0 112 to 20049 )45C210 60 1532 . 45 7.563 40 05 112W Some 1 8 2W Lots of Precisions Carbon Film Multi Turn Precision Tronpors, 50 OHM. 100 OHM. 200 Capacitance toF to 2000 bAS. 75 40 741.5115 40 4555 75 Taped and Reeled for Easy Sorting $9 95 OHM. 250 OHM. 500 OHM. 10 20. 5K. 10K. 20K. 25K. OH. Two lavers 001111641 testing SS ..5116 fie en ioci3O, -O-O Jumper Plugs (Cambwn) - MaH to Male Mr Bread M. 14.61 Iranstslor letting ", 4.5 35 50K. 100K. 200K. 250K. 500K. 1Meg 75 Ext., 103/566 45 7.590 40 so .73 45 board 8 Connectors 10/51 25 411 100 141593 Zenith TV Replacement C Special SI Each 22142. 35 745C373 so 45/ 4 45 so 7.5107 9VDC Wall Transformer. 200ma 52 95 221.43, 221 48.221.69. 221-79. 22187, 221-96. 10 resoere oo 456. 70 UHF -TV PR IAP SO 741.5. 9VDC Wall Transformer 50Orna T5 rase s» so 4.5 70 5395 221.104, 221105. 22,106, 221.140 (As featured in Radio Electronics March/ 70 745113 30 ,-o-oZ000 oo Hose 4, 12VDC Wall Translormer, 400ma 56 95 Moller, Detector Module (Includes ULN2232 CO Cape). ' May artcles. 1982) 50 7.5114 30 oo 40.07 4, 6 3V 12A Transformer 7.51)3 Sr 60 S2 Each, 7/510. 25/525 45 sc.,, so 0.. 45 12.6 OCT 1A Thos meapensive antenna mounted pre- , 60 7475.25 35 S3 50 Motion Detect. ULN2232 IC Only 3/52. 20310 Black$2 /45C564 60 BO 745,26 30 7 (Seven) Amp Tapped Transformer - 7 I/2/15VAC Plastic Case for Detector 25, amp Can add more than 25 dB of gam to ,o si. 3, or 9WIEWAC your system Lois 01 SBOSOIKI customers ,ester,"sc" / 4'. EPROOMME2 00 SO 95 Miniature Speaker 10. Detector .75 2 7t6 2 95 Muffin/Sprite Style Fan eSU2C7 1EG 8 G Rotron) ...atii SG105 Signal GeneraMr - 201-1, to 150 kHz. and repeat orders for fhts high Quaid), lot. 1 1/:12:341 w" DAT' 5.°°' ,,/22 /,/, 3 1/2" Sq. 115V S5 95 a Disionion. 46 STEP whch Includes all component parts. PC . 145.9/. Frrow°" ii 2 50 "...." 25 545.95 70 M1.5,51 40 222»» Jumbo Red LED's 15/51.00. 100/$6 00 14 PIN Enron .1, Ciin-iiiiii 65 BO. Case. Power Supply and aalun 534 50 60 7475.53 35 - CMOS SERIES aa a ,,,, Jumbo Green LED's 40/51 30. 100/510 00 in N 1DC .- Or Assembled Verston S57 50 771 1415157 13 74000 75 6335 t 25 Jumbo Yellow LED's Iasi 40. loon" 00 NIL St. TO X 4000 .95 1 05 Jumbo Yellow Hi Intensity with RI Angle 8 Black Case 760.5,60 .25 400, TO 2.0.4 C TC 1 )5 Features ,, 7415161 45 4032 TO UPN61.6445040W i0/51 20. 100/$10 TOM: MICRO -MART accepts Visa. MC and telephone CODs Minimum order 510 00 Shipping - tr SS 745.62 45 4006 w o0.5.3,0 so Jumbo- Amber LED's t0/$140, icon, 1 De US orders. S250 Canada and other countries.$3 50 Shipping rate adjusted where applicable ,4, ,.si43 eon, m UC.610. 60 Mini Yellow Hi Intensity with Discreet. Pale Blue N J residents add 6., sales tax 00.111.4 55 LensiCasa Feature 10/1 20. 100110 LED Clips/Rings for Jumbo 5/$1 100/$6 MICRO -MART 508 CENTRAL AVE.. WESTFIELD,NJ 07090 12011654-6008 138 CIRCLE 63 ON FREE INFORMATION CARD Radio /limit Part/ PlaeeT--%m ELECTRONIC VALUES AT OUR STORE NEAR YOU

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(7) i Min/Max Values Can Be Stored (5) High -Torque, Low -Voltage Motor. 1.5-3 VDC, approximately 8300 RPM A champion performer for shop or laboratory. The 31 -segment analog bar (1) Brilliant Red LED. #276-066 . 1.19 #273-223 790 graph display makes input peaks and trends easier to follow. Transistor (2) Big Red LED. #276-064 3 49 (6) 1:1 Audio Transformer. For phone checker measures h (gain), diode -check for semiconductor junctions. (3) Tri-Sound Siren. Extra -loud buzzer interconnects. #273-1374 3 49 Memory function and buzzer continu ty checker. Measures to 1000 VDC, 750 outputs #273-072 5 95 (7) Magnet Wire. Three spool set -22, VAC, AC/DC current to 10 amps, resistance to 30 megohms. Input impe- (4) Melodic IC Chime. #273-071.. 7.95 26. 30 gauge #278-1345 4.49 dance: 10 megohms on DCV/ACV. Fused, overload protected. #22-195 Coax Cable TOols Phono Plugs, Jacks Solder -Type "Co" Submini Connectors (12) (15) vrvorrIr (18) u=1.11153i (11) Id 411"11Q- (8) (17:

NEW tt (14) vieliallill791 .ainmp (16) r 03) 1.4aitoo4AY-11131. 4-. .41 204kilaftwas(10) (19) (11) Solderless 90° Plugs. Two red, Fig Type Positions Cat. No. Ea (18) Printer Connector. Solder (8) Cable Stripper. For all popular sizes. two black #274.383 Set of 4/1.59 15 Male 9 276-1537 1.49 16 Female 9 2764538 2.49 type, 36 -position. For parallel .278-240 . 11.95 (12) Shielded Plug. 17 Hood 9 276-1539 printers. #276-1534 4 99 (9) Coax Cable Cutter. Blades do not flat- .274-339 Set of 2/1.49 1.99 ten cable, preserve impedance. (13) Shielded Jack. Type Positions Cat. No. Ea. (19) RS232 Inline Tester. Diag- #278-244 4 95 #274-338 Set of 2/1.49 Male 25 2781547 1.99 nose interface problems without (10) Professional Crimp Tool. For all (14) Dual Phono Jacks. Chassis Female 25 276-1548 2.99 costly repair calls. coax connectors #278-243 12.95 mount #274-332 Set of 2/1.19 Hood 25 276-t549 199 #276-1401 14.95 Hard -to -Find Parts Irresistables Our Newest ICs Voice Synthesis ICs (23) ; (24) NEW NEW! TDA7000 FM Receiver on a SP0256-AL2 Speech Synthe- if Chip. Combines RF mixer, IF and sizer IC. Give your computer a (21) ? 77 demodulato, stages in one IC. Just voice! Built-in program makes it I, IF what you need to build a small, in- easy to interface with most comput- s.1' expensive FM band receiver or ers. Requires 3.12 MHz crystal public service band monitor. In- (20) (special order). 28 -pin DIP. ,12 (26) cludes application notes. #276-1784 12.95 4.(25) NEW! #276-1304 5 95 CTS256-AL2 Text -to -Speech IC. NEW (22) NEW! TDA1520A 20 -Watt High - (23)1/8 -Watt Carbon Film Resistors. Preprogrammed 8 -bit processor (20) CPU/RAM Backup Capacitor. For 100 Asstd. #271-311 1 98 Power, High -Fidelity Audio translates ASCII characters into CMOS microprocessors 01 farad, 5.5 (24) 1/...Watt Carbon Film Resistors. Power Amp. Build your owl qual- control data for #276-1784 above. WVDC. #272-1440 2 95 500 Asstd. #271.312 7 95 ity audio amplifier! Nine -pin single With data and schematics. Re- (21) Dual -Ganged 335 pF Pot. PC mount (25) Set of 12 Asstd. Trimmers. inline package. Very low distortion. quires 10 MHz crystal (available With knob. pinout. #272.1337 4 95 #271-1605 1 98 20 to 20,000 Hz response. Re- from our warehouse via special or- (22) 6-50 pF Trimmers. PCfperibOard (26) Thermistor. -50 to +110°C. quires 15 to 50 VDC. With data. der "Hotline"). 40 -pin DIP. mount .272-1340 Set of 2/1.59 271-11O 1 99 #276-1305 5 99 #276-1786 16.95 RAM & Data-Xfer ICs Top -Duality Op Amps Musical Chips CMOS and TTL ICs 741. General-purpose workhorse. UMC 3482 12 -Tune Melody Syn- All include pin -out and specs and Why gamble with mail order? Factory Frequency -compensated, 8 -pin DIP fresh, warrantied popular parts in stock thesizer IC. Just the thing for musi- are 1000/0 prime. #276-007 790 cal doorbel's, clocks, games and and Radio Shack close. Description Cat. No. Each 1458 Dual Op Amp. Internally compen- phone mus c -on -hold. Has an on - Type sated. Two independent op amps in an 8 - Quad 2 -Input NOR Gate 4001276-2401 .99 pin DIP Split supply. 5 to 16 VDC. chip audio preamp. Some of the Quad 2 -Input NANO Gate4011276-2411 .99 4164-64K Dynamic RAM. Factory fresh, #276-038 99e tunes are Happy Birthday. Row - 150 ns access, low -power design. Uses sin - Row -Row Your Boat and other all- Dual Type -0 Flip Flop 40132762413 1.19 5 VDC supply. #276-2506 3.95 LM324 Quad Op Amp. Operates on 3 to 30 VDC or split 1.5 to 15 VDC supply 14 - time "camp" favorites. Operates Decade Counter/Divider4017276.2417 1.49 TMS 4256-256K Dynamic RAM. 150 ns pin DIP #276-1711 1 29 on 1.5 VDC, 16 -pin DIP. With data Inverting Hex Buller 4049276-2449 1.19 maximum access time. Low -power design TL082 Dual BiFET Op Amp. Low -noise, and circuit examples. Ouad Bilateral Switch 4066276-2466 1.19 (230 mV typical). Uses single 5 VDC power high -Z inputs Split 4 10 18 VDC supply 8 - #276-1797 2 99 supply. 16 -pin DIP #276-1252 6 95 pin DIP. #276-1715 1 89 MC1488 RS232 Ouad Line Driver. Lets LM339 Quad Comparator. Four inde- AY -3-8910A Programmable Description TypeCat. No. Each pendent voltage comparators in a 14 -pin you hook up terminals and remote periph- Sound Generator. Produces an Quad 2 -Input NAND Gate7400276-1801 .89 erals with a simple "twisted pair" cable. 14 - DIP Single 2 to 32 VDC supply. astonishing variety and range of #276-1712 990 Hex Inverter 7404276-1802 .99 pin DIP with data. #276-2520 1 29 sounds! Three independently pro- LM567 Tone Detector. Use for Touch - Quad 2 -Input AND Gate7406276-1822 1.29 MC1489 RS232 Quad Line Receiver. For Tone, remote control and FSK decoding. grammable analog outputs. Single use with above line driver 14 -pin DIP with Requires 4.75 to 9 VDC 8 -pin DIP. 5 VDC supply, 40 -pin DIP. With BCD to 7-Seg. Driver 7447276-1805 1.69 Data. #276-2521 1 29 #276-1721 1 99 Data. #276-1787 9 95 Div by 2/5 BCD Counter7490276-1808 1.19

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CIRCLE 78 ON FREE INFORMATION CARD 139 mat amm im,mt =Mr IN AWN IM NH I 1MMI - - - - IM CORPORATION/1-800-344-4539/AK, Puerto Rico 218.681 6674 Telex 62827914 FAX 218 681 3380 TWX 9103508982 MG! KEY CORP

NATIONAL SEMICONDUCTOR PANASON ,,..1,-'7, )10DES DIAMOND TOL UNGAR OK MACHINE EWC, INC. NTERSIL AD '7' 1/5011 ,,,j''y 256K (262,144 x 1) DRAM 15ONS $5.7011; $30.0510 ES CW INDUSTRIES O AMDEK G.E EAC INC. J. W. MILLER AAVID ENG NFl'''`,, S i' ,IGAR YAGEO J. W MILLER LUXO E F., JOHNSON ATLANTIC SEMICONDUC''1",*'' Factory Firsts 3C CHEMICALS ARIES PLESSEY - INTEGRATED CIRCUITS 1111177.1=r=. 0111121112123IMIiiiilPaiiligi;g111 7400 1-1-5 4000 CMOS ... .3. SOLDER TAIL 6. . ,. c vel 6 ' 12 1 oo ,423.7 DIP SOCKETS ...... ---- . Jill 6( V 1 311 - .3 . 3 ...... , . 113 31 370 3. t.'.:I .3 IS 315 42 3. 3056 I: L...... 52 90/391C1401C151.1 O. 401.0. . 22 3/5 4. on WO 13 115 61 SO 45 0. . . , in I. t a 47 315 66 56/ 4)15 3 2 OS SOO 811 315 711 .V. ..' .6...I -L..... X 6 75 5.3 ::I '''' . , ...... t.t lib . 15 2 77 19 SO 162 . .75 1 11 . at..., IE. .96 arn to rxec 503 / a 2 70 3. .7561,6 . Mow. .8 on solda. . 13 1 IS .41 64 37 3 21 2681 10.464.34 on 15 316 850 950 mall 1. . 1 10 SO 439 : ; 0 503 66 358, .3 I.P.10101..11 On 17 I. . :I: 66 567 47 3 . I 63 401611 .70,01.34. 0 23 2 10 2.4013 3 6. 516 MI 75 . 3,...,63 0 3 2 23 1 0 to 4 /V Lorpor.i.n.... D13. 6 On. 11 6 21 51 3 . 11 3 563 t . 441 I 14 9 .3 .1 72 6 2 93 . 265 2116 ION .- 28....1. 0 '.. . . 374 330 1,5., 34 320 30 CC 4. 3 ., OP 691

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TENMA 1 00MHz Multifunction Counter Eight digit non -glare LED display Selectable gate time Frequency. period. totalize and self test functions Data hold Selectable attenuator and variable trigger level Switchable AC and DC coupling sysems #72-465

TENMA 1 GHz TENMA Dual Trace Multifunction Counter 35MHz Oscilloscope Eight digit non -glare LED display Two 10:1 Drobes included High brightness CRT Selectable gate time Frequency. with internal graticule 6KV accele ating potential period, totalize and self test functions 5x vertica and horizontal magnifiers Delayed Data hold Selectable attenuator AC triggering sweep Front panel elec:rical trace coupling system #72-460 rotation Alternate triggering permits viewing of asynchronous channel A and channel B signals #72-330

TENMA AC Millivoltmeter This is perfect for servicing and designing E udio products as well as measuring the outputs of audio and video heads. 3' mirrc red scale Calibrated in mV RMS and dB Amplified output for observing microvolt s gnals on TENMA TENMA oscilloscope Comes complete Sweep Generator Pulse Generator with test leads and owners Produces square. sine, triangle, TTL or CMOS pulse output manual #72-450 ramp and pulse waveforms Built-in logic tester Can be used Continuously variable sweep with oscilloscope to provide sweep width and time Variable and fixed delay Variable pulse width and output attenuators Voltage spacing #72-470 TENMA controlled frequency (VCF) input Audio Generator #72-475 Generates sine and square waveforms Six step and continuously variable attenuators External sync input Laser Power Meter Comes complete with test Measures output of laser devices leads and owners manual on audio and video disc players #72-455 Two wavelengths and three power ranges give this instrument the versatility to be used in servicing the equipment of many CD and For more test equipment. see pages laser disc manufacturers #70-420 145-158 of our newest catalog!

For A Wide Variety Of Electronic Parts Call Toll Free 1-800-543-4330 In Ohio, 1-800-762-4315 - In Alaska and Hawaii, 1-800-858-1849 CIRCLE 87 ON FREE INFORMATION CARD

c 1987. MCM ELECTRONICS MCM ELECTRONICS 858 E. CONGRESS PARK DR CENTERVILLE, OH 45459 SOURCE NO. RE -38 A PREMIER Company 20 MEG HARD DISK DRIVE ON A CARD $349! r- STATIC RAMS /DYNAMIC RAMS **** HIGH-TECH **** EPROMS 2101 256.4 (450.$) 1 95 1024.1 2708 1024.8 1450nsI 4.95 21021-4 I 45OnsIlli hriP. eve, p .99 2716 2048.8 (450ns)(5V) 2112 256.4 1450ns) 2.99 3.49 1024.4 2716-1 2048.8 1350ns115V) 3.95 2114 (450ns) .99 TMS2532 4096.8 (45Ons115V) 21141.4 1024.4 (450ns)(LPI 1.09 80387 $495.00 5.95 2732 4096.8 145Ons115V) 3.95 21141-2 1024.4 (200ns91P) 1.49 2732A 4096.8 21141-15 1024.4 (150nsIILP) 1.95 1250ns115V1(21V PGM) 3.95 * 16 MEGAHERTZ MATH CO-PROCEESOR IN A 2732A-2 4096.8 1200ria115V)(21V PGM) 4.25 TMS4044-4 4096.1 (450ns) 1.95 27C64 TMM2016- 150 2048.8 PIN GRID ARRAY 8192.8 125Ons)15VIICMOS) 4.95 (150ns) 1.49 2764 8192.8 (450rts115V) TMM2016-100 2048.8 (10Ons) 1.95 * FOR INTEL INBOARD AND OTHER 30386 3.49 2764-250 8192.8 1250ns)15V) 3.69 HM6116-4 2048.8 1200rts1ICMOS) 1.79 2764.200 (200ns)15V) HM6116 3 2048.8 (150ns1ICMOSI BASED COMPUTERS 8192.8 4.25 1.85 MCM68766 8192.8 (350ns)(5V)(24 PIN) 15.95 HM61161P-4 2048.8 (200n.11CMOSIILP/ 1.85 * GET ALL THE SPEED AND POWER YOUR 27128 16384.8 HM6116LP-3 2048.8 (150ns1ICMOSIILP) 1.90 1250ns)15V) 4.25 MACHINE CAN DELIVER 27C256 32768.8 1250ns115VIICMOSI 7.95 HM61161P-2 2048.8 1120ns1ICMOSIILP) 2.45 27256 32768.8 HM6264P-15 8192.8 (150ns)(CMOS) 3.89 * GREAT ADDITION FOR CAD, SPREADSHEET 1250ns1(5V) 5.95 27512 65536.8 1250ns115V) 11.95 HM62641P-15 8192.8 1150nal(CMOS)ILP) 3.95 AND OTHER POWER PROGRAMS 27C512 65536.8 1250ns115V1(CMOS) 12.95 HM6264LP.12 8192.8 I 1 2Ons)(CMOS)ILP) 4.49 5V Single 5 Volt Supply 21V PGM- Program at 21 Volt' HM43256LP 1532768.8 115OnslICMOS)11P) 12.95 HM432561P-1232768.8 (120ns1ICMOS)ILP) 14.95 HM4325E4,-1032768.8 (10Ons)(CMOSI(LP) 19.95 **** SPOTLIGHT **** 4116-250 16384.1 (250ns) 49 4116.200 16384.1 (2013ns) .89 nSPECTRONICS 4116-150 16384.1 I150ns) .99 PA CORPORATIONEPROM ERASERS 4116-120 16384.1 I120ns) 1.49 MK4332 32768.1 (200ns) 6.95 U.S. AND CANADA 4164-150 65536.1 (150ns) 1.29 4164-120 65536.1 (120ns) 1.55 MCM6665 65536.1 (200ns) 1.95 TMS4164 65536.1 (150ns) 1.95 4164 -REFRESH65536.1 1150nsli PIN IHLI Ht 514 2.95 ORDER TOLL FREE TMS4416 16384.4 1150nsl 3.75 41128-150 131072.1 (150ns1 5.95 TMS4464-15 65536.4 (150ns) 4.95 41256-150 262144.1 1150ns1 2.95 Model Tinter Capacity Intensity Unit 41256-120 262144.1 (120rts) 3.95 800-538-5000 Chip (aIN/Cm) Price 41256.100 262144.1 00ns) 4.95 PE -14 HM51258-100 262144.1 110Ons1ICMOSI 6.95 NO 9 8.000 *83.00 1 MB -120 1048576.1 (120ns) 19.95 PE -14T YES 9 8.000 8119.00 1 MB100 1048576.1 (10Cins) 24.95 NSA PE241 YES 12 9,600 4175.00

8000 V 20 SERIES 6500 CRYSTALS 741500 HIGH SPEED CMOS 1.49 8035 V20* 5 MH. 8.95 32.768 KU. .95 A new family of high speed CMOS logo featunng 8039 1.95 1.0 MHZ 741500 .16 7415165 .65 V20. 8 MU. 10.95 1.0 MHz 2.95 741601 .18 7416166 .95 the speed of low power Schottky 18ns typtcal gate 8052AH BASIC 34.95 V30 8 MHz 13.95 6502 2.69 1.8432 2.95 2.95 741502 .17 7415169 .95 propagation delay), combined with the advantages of 8080 'Replaces 8088 to 65CO2 0-M05112.95 2.0 1.95 8085 2.49 741603 .18 7415173 .49 CMOS very low power consumption. superior none speed up your PC 6507 9.95 2.097152 1.95 741604 immunity. and improved output dove 8087 5MHr 129.00 by 10 to 40% 6520 1.95 16 7415174 .39 2.4576 1.95 741505 .18 7416175 .39 8087-2 8MHr 169.95 6522 4.95 3.2768 1.95 7411C00 8088 6.95 6526 26.95 741508 .18 7415191 .49 9.95 3.579545 1.95 741609 .18 7415192 .69 74HC: Operate at CMOS logic levels and are deal 8088-2 6532 6.95 4.0 1.95 8155 2.49 6545 6.95 741510 .16 7415193 .69 for new. all-CMOS designs CRT 4.032 1.95 741511 .22 741S194 .69 8748 7.95 6551 5.95 5.0 1.95 74HCOO .59 74HC148 1.19 8755 14.95 6561 19.95 741512 .22 7415195 .69 74HCO2 .59 74HC151 .89 CONTROLLERS 5.0688 1.95 741613 .26 7416196 .59 80286 129.95 6581 34.95 6.0 1.95 74HC04 .59 74HC154 2.49 80287 6MH, 199.95 6845 495 741514 .39 7415197 .59 74HCO8 .59 74HC157 .89 68845 895 6.144 1.95 741515 .26 7415221 .59 80287-8 8MHe 299.95 2.0 MHZ 6.5536 1.95 74HC10 .59 74HC158 .95 802137.10105111z 399.95 6847 11 95 741S20 .17 7415240 .69 74HC14 .79 74HC163 1.15 6502A 2.95 8.0 1.95 741S21 .22 741S241 .69 HI:146505SP 695 6520A 2.95 74HC20 .59 74HC175 .99 MC1372 295 10.0 1.95 741622 .22 7415242 .69 6522A 5.95 10.738635 1.95 74HC27 .59 74HC240 1.89 8275 2695 .69 74HC30 .59 74HC244 1.89 1995 6532A 11.95 12.0 1.95 741S28 .26 7416244 7220 6545A 7.95 .69 74HC32 .69 74HC245 1.89 8200 CRT5027 1295 14.31818 1.95 741630 .17 7416245 .79 8205 3.29 6551A 6.95 15.0 1.95 74HC51 .59 74HC257 .85 CRT5037 995 741532 .18 7416251 .49 74HC74 .75 74HC259 1.39 8212 1.49 TMS9918A 1995 16.0 1.95 741533 .28 7416253 .49 8216 1.49 3.0 MHZ 17.430 1.95 74HC85 1.35 74HC273 1.89 74LS37 .26 74152561.79 74HC86 .69 74HC299 4.99 8224 2.25 65028 6.95 18.0 1.95 741538 .26 7416257 .39 8237 4.95 18.432 1.95 74HC93 1.19 74HC368 .99 741642 .39 741S258 .49 74HC107 .79 74HC373 2.29 8237.5 5.49 20.0 1.95 741647 .75 74152591.29 8250 6.95 DISK 22.1184 1.95 74HC109 .79 74HC 374 2.29 741548 .85 7415260 A9 74HC112 .79 74HC390 1.39 8251 1.69 6600 24.0 1.95 741651 .17 741S266 .39 8251A 1.89 CONTROLLERS 32.0 1 95 74HC125 1.19 74HC393 1.39 741S73 .29 7416273 .79 74HC132 1.19 74HC4017 1.99 8253 1.89 1771 495 1.0 MHz 741674 .24 7415279 .39 1791 9.95 CRYSTAL 74HC133 .69 74HC4020 1.39 8253-5 1.95 6800 1.95 741575 .29 74152801.98 8255 1.69 1793 9.95 74HC138 .99 74HC4049 .89 6802 4.95 OSCILLATORS 741376 .29 7416283 .59 74HC139 .99 74HC4050 .89 8255-5 1.89 1795 1295 6803 9.95 741583 .49 7415290 .89 8259 1.95 1797 12.95 6809 5.95 1 OMH, 5 95 741S85 .49 7415293 .89 8259-5 2.29 2791 19.95 1 8432 5.95 741586 .22 74162991.49 74HCTOO 19.95 6809E 5.95 8272 4.95 2793 6810 1.95 20 5.95 741690 .39 74LS3223.95 74HCT: Direct. drop -in replacements for LS TTL 8279 2.49 2797 29.95 6820 2.95 2 45/6 5.95 741592 .49 74LS3232.49 and can be intermixed with 741.5 in the same orcurt 8279-5 2.95 8272 495 6821 1.95 2.5 4.95 741593 .39 74163641.95 UPD765 495 4.0 4.95 74HCTOO .69 74HCT166 3.05 8282 3.95 6840 6.95 741695 .49 74/6365 .39 74HCTO2 8284 2.95 M138876 12.95 5.0688 4.95 .69 74HCT174 1.09 6843 19.95 741S107 .34 7415367 .39 74HCTO4 .69 7414CT193 1.39 8286 3.95 MB8877 1295 6844 12.95 6.0 4.95 7415109 .36 7415368 .39 0288 4.95 1691 6.95 6.144 4.95 74HCTO8 .69 74HCT194 1.19 6845 4.95 7416112 .29 7415373 .79 74HCT10 .69 74HCT240 2.19 2143 695 6847 11.95 8.0 4.95 7416122 .45 7416374 .79 9216 795 10.0 4.95 74HCT11 .69 74HCT241 2.19 6850 1.95 741S123 .49 741S375 .95 74HCT27 .69 74HCT244 2.19 6883 22.95 12.0 4.95 741S124 2.75 7416377 .79 12.480 4.95 74HCT30 .69 74HCT245 2.19 Z-80 7415125 .39 74163781.18 74HCT32 .79 74HCT257 .99 2.0 MHZ 15.0 4.95 741S126 .39 74153901.19 Z80 CPU 1 69 16.0 4.95 74HCT74 .85 74HCT259 1.59 BIT RATE 68B00 4.95 7416132 .39 7416393 .79 74HCT75 .95 74HCT273 2.09 4.0 MHz 18.432 4.95 741S133 49 74165411.49 GENERATORS 68802 5.95 20.0 4.95 74HCT138 1.15 74HCT367 1.09 68E109E 6.95 7415136 .39 74166241.95 74HCT139 1.15 74HCT373 280A CPU 1 79 24.0 4.95 7415138 2.49 280ACTC 1.89 MC14411 9 95 6.95 .39 7416640 .99 74HCT154 2.99 74HCT374 2.49 1381941 4.95 681321 3.95 7416139 .39 7415645 .99 74HCT157 .99 74HCT393 280A -DART 5.95 7415145 1.59 280A -DMA 5.95 4702 9 95 68845 6.95 .99 74166691.29 74HCT158 .99 74HCT4017 2.19 COM8116 8 95 681350 2.95 7415147 .99 7416670 .89 74HCT161 1.29 74HCT4040 280A -P10 1 89 MISC. 7415148 1.59 280A SIO 0 5.95 681354 7.95 .99 74166823.20 74HCT164 1.39 74HCT4060 1.49 MAX232 7.95 7415151 .39 74166833.20 Z80A SIO 1 5.95 7416153 .39 7416684 280A -S10 2 5.95 TMS99532 19.95 3.20 DARTS ULN2003 .79 74161541.49 7416688 2.40 6.0 MHZ 3242 7.95 741S155 .59 7416783 22.95 AY5-1013 395 CLOCK 3341 4.95 7415156 .49 811S95 1.49 74F00 2808 -CPU 3.75 AY3-1015 4.95 CIRCUITS MC3470 1 95 7416157 .35 811696 1.49 74600 .69 74F74 .79 746251 1.69 ZBOB CTC 4.25 TR1602 3.95 MC3480 8.95 7415158 .29 811597 1.49 74602 69 74686 .99 746253 1.69 21308-P10 4.25 2651 495 MM5369 1.95 MC3487 2.95 7415160 .29 811598 1.49 74604 79 746138 1.69 746257 1.69 28O13 -DART 14 95 IM6402 695 MM5369-EST 1.95 11C90 19.95 7416161 .39 25152521 2.80 74608 .69 746139 1.69 746280 1.79 2808 SIO 0 12.95 IM6403 995 MM58167 12.95 2513-001 t IP 6.95 7415162 .49 25162569 2.80 74610 .69 746157 1.69 746283 3.95 2806.510 2 12.95 INS8250 695 MM58174 11.95 AY5-2376 11.95 7416163 .39 261531 1.95 74632 .69 746240 3.29 746373 4.29 Z8671 ZILOG 19.95 NS16450 15.95 MSM5832 2.95 AV5-3600 P.0 11.95 7415164 .49 261532 1.95 L74664 .89 746244 3.29 74F3744.29 NEW STORE HOURS! M -F: 9-7, SAT: 9-5 & SUN: 12-4 Visit our retail store located at 1256 S. Bascom Ave. in San Jose, (408) 947-8881 PLEASE USE YOUR CUSTOMER NUMBER WHEN ORDERING TERMS: Minimum order 510.00 For shipping and handling include 52.50 for UPS JDR Microdevices Ground and 53.50 for UPS Air. Orders Over 1 lb and foreign orders may require additional shipping charges -please contact our sales department for the amount. CA. residents 110 Knowles Drive, Los Gatos, CA 95030 must Include applicable sales tan. All merchandise is warranted for 90 days unless otherwise stated. Prices are subject lo change without notice We are not responsible for Toll Free 800-538-5000 (408) 866-6200 typographical errors. We reserve the right to limit quantities and to substitute manufacturer. All merchandise subject to pnor sale. A lull copy of our terms is available upon FAX (408) 378-8927 Telex 171-110 request. Items pictured may only be representative. COPYRIGHT 1987 JDR MICRODEVICES THE JDR MICRODEVICES LOGO IS A REGISTERED TRADEMARK OF JOR MICRODEVICES JDR INSTRUMENTS AND JDR MICRODEVICES ARE TRADEMARKS OF JDR MICRODEVICES IBM IS A TRADEMARK OF INTERNATIONAL BUSINESS MACHINES CORPORATION. AFPLE IS A TRADEMARK OF APPLE COMPUTER 142 CIRCLE 113 ON FREE INFORMATION CARD EGA CARD AND MONITOR NOW $499! MONITOR STANDS CRT MONITORS FOR ALL APPLICATIONS SOLDER STATION MODEL MS -100 $12.95 JDR PART X 168-2C FULLY ADJUSTABLE HEAT TILTS AND SWIVELS STURDY ABS PLASTIC CONSTRUCTION SETTING WITH TIP TEMP- ERATURE READOUT MODEL MS -200 QUICK HEATING AND $39.95 RECOVERY TILTS AND SWIVELS VARIETY OF REPLACE BUILT-IN POWER STATION MENT TIPS ARE AVAILABLE INDEPENDANTLY CONTROLS UP TO 5 RANGE 200,900"F 120 VOLT AC OUT _ETS UL APPROVED BUILT-IN SURGE SUPRESSOR UL APPROVED 44111.1W CASPER CASPER $4995 EGA MONITOR RGB MONITOR EGA & CGA COMPATIBLE :;OLOF GREEN AMBER IBM COMPATIBLE TTI INPUT SCANNING FREQUENCIES SWITCH ON REAR 12 NON G ARE SCREEN 15 75 21 85 KHr DIGITAL RGB IBM COMPATIBLE VERY HIGH RESOLUT ON 'aLa ire RES 640 200 350 14 NON GLARE SCREEN 1100 LINES ICENTER 31nin, DOT PITCH. 25 MHz RESOLUTION 640H 240V 25 MHz BABDWIDTH

16 COLORS OUT OF 64 39.n." DOT PITCH CABLE FOR IBM PC INCLUDED 14" BLACK MATRIX SCREEN CABLE FOR IBM PC INCLUDE AMBER 01 DIEENIVAIABLE DISK DRIVES $399.95 $279.95 $99.95 FOR APPLE COMPUTERS 1 20 APPLE COMPATIBLE INTERFACE CARDS MEGABYTE HARD DISK CARD AP -150 $99.95 V, HT, DIRECT DRIVE 100% APPLE COM PATIBLE SIX MONTH WARRANTY EPROM PROGRAMMER 16k RAMCARD IC TEST CARD DUPLICATE UR BURN ANY FULL / YEAR WARRANTY SAVES SPACE AND REDUCES POWER OUCKLY TESTS MANY CONSUMPTION 27.. SERIES EPROM EXPAND YOU3 48K MACHINE COMMON ICs 12716 TO 271281 IDEAL FOR PCs WITH FULL HEIGHT TO A RAC 641 OF MEMORY DIS,LAYS PASS OR FAIL FLOPPIES MENU DRIVEN SOFTWARE CANE USED IN PLACE OF TEST 4000 & 74HC SERIES HIGH SPEED WRITE ALGID LEAVES ROOM FOR A HALF LENGTH 111).4 THE A'PLE LANGUAGE CARD CMDS, 7400 74LS 741. CARD IN ADJACENT SLOT RITIIM 74111, 74S

AP -135 RP -525 $5995 RAM -CARD $3995 IC -TESTER $12395 $129.95

FULL HT SHUGART MECHANISM NOW $349 DIRECT REPLACEMENT FOR APPLE DISK II MOLDED INTERFACE CABLES rC. ITOH RITEMAN II PRIMER SIX MONTH WARRANTY 6 FOOT, 100% SHIELDED. MEETS FCr cg Seagate 51/4" HARD DISK DRIVES ST -225 HALF HT 20M8 65ms 5275 AD -3C ST -238 HALF HT 30MB 65ms IRLLI5299 ST -251 HALF HT 40MB 4Orns 5469 $139.95 ST -277 HALF HT 60MB 40rns IRLLI 5649 ST -4038 FULL HT 30MB 40rns 5559 100. APPLE Ilc COMPATIBLE, ST -4096 FULL HT BOMB 28ms READY TO PLUG IPA, W SHIELDED IBM PARALLEL PRINTER CABLE 9.95 ,1 1 35 CABLE & MOLDED 19 PIN 111111111111M11111111111111! CONNECTOR CENTRONICS (MALE TO FEMALE) 5.95 160 CPS DRAF-. 32 CPS NLQ FAST RELIABLE SLIMUNE DIRECT CENTRONICS (MALE TO MALE) 4.95 9 K 9 DOT MATRIX DRIVE MODEM CABLE (FOR IBM) 7.95 SUPPORTS EPSON IBM GRAPHICS SIX MONTH WARRANTY RS232 SERIAL (MALE TO FEMALE) 9.95 FRICTION AND PIN FEEDS 1/2 HEIGHT FLOPPY DISK DRIVES RS232 SERIAL (MALE TO MALE) 9.95 VARIABLE LINE SPACING AND ',ETCH KEYBOARD EXTENDER (COILED) 7.95 5' ." TEAC FD -55B OS DD 5109.95 DISK DRIVE ACCESSORIES APPLE II JOYSTICK EXTENDER 4.95 TEAC FD -55F DS QUAD 5124.95 FDD CONTROLLER CARD 549.95 ." TEAC FD.55GFV DS HD 5154.95 11r. ADAPTOR CABLE 119.95 5'." MITSUBISHI DS HD 5119.95 ADAPTS STANDARD APPLE DRIVES 3'.," FDD KIT DS DD $149.95 FOR USE WITH APPLE lIc SWITCH BOXES $219.95 KIT INCLUDES MOUNTING HARDWARE TO ALL LINES SWITCHED. GOLD PLATED IBM PAINTER COL FIT 5' ."SLOT A TA ST VERSIONS AVAILABLE CONNECTORS, QUALITY SWITCHES LGENACEMENT RIBBON CARTRIDGE $7 II5 KB -1000 DISK DRIVE ACCESSORIES $79.95 2 WAY $39.95 TEAC SPECIFICATION MANUAL 55.00 CASE WITH KEYBOARD CONNECTS 2 PRINTERS TO 1 TEAC MAINTENANCE MANUAL 525.00 FOR APPLE TYPE MOTHERBOARD COMPUTER OR VICE VERSA NASHUA DISKETTES HT MNTG HARDWARE FOR IBM S2.95 MOUNTING RAILS FOR IBM AT $4.95 USER DEFINED FUNCTION KEYS Al -P (CENTRONICS PARALLEL) NASHUA DISK E IIE S WE RE JUUI;EU IC HAVE THE HIGHEST POLISH AND RECCADFD -Y" POWER CABLE FOR 5'." FOOs$2.95 NUMERIC KEYPAD W CURSOR CONTROL S". FDD POWER CONNECTORS 51.19 CAPS LOCK AUTO -REPEAT WS (RS232 SERIAL) AMPLITUDE OF ANY DISKETTES TESTED sir... - !COMPARING F_OPPY DISKS. BYTE 9.941

N-MD2D DS DD 5' ." SOFT 39.90 DISK DRIVE ENCLOSURES N-MD2F OS QUAD 5' ." SOFT$19.95 N-MD2H DS HD 5' ." FOR AT8124.95 WITH POWER SUPPLIES NMI N-FD1 5'S CID 8" SOFT $37.95 CAB-2SV5 DUAL SUMLINE 5' . 1498` N-FD20 DS CID 8" SOFT $34.95 CAB-1FH5 FULL HT 5' ." 169" 3 WAY $99.95 CAB-2SVB DUAL SLIMUNE 8" 120995 CONNECTS 3 PRINTERS TO 1 COMPUTER OR VICE VERSA BULK DISKETTE SALE CAB-2FH8 DUAL FULL HT8- 12199, SWITCH -3P (CENTRONICS PARALLEL) 5'-."" SOFT SECTOR, DS DD SIIIITCH-38 (RS232 SERIAL) W TYVEC SLEEVES & HUB RINGS BUILD STEVE CIARCIA'S rJOYSTICK BC -10 $19.9e $99069Cea 59Cee 8116 01950 BUN OM 2511 SET X -Y AXIS FOR AUTO CENTER OR L.±9"OF 10 _A FREE MOVEMEN- INTELLIGENT FIRE BUTTON FOR USE WITH GAME SOFTWARE EPROM PROGRAMMER ATTRACTIVE. SOLID. PLASTIC CASE DISKETTE FILES 4'. SEEN IN BYTE, OCT 96 INCLUDES ADAP-OR CABLE FOR IBM, APPLE IL II. 5I/ DISIFILE 31/2" DISKFILE STAND ALONE OR RS -232 SERIAL HOLDS 70 OPERATION POWER STRIP $9.95 HOLDS 40 MENU SELECTABLE EPROM TYPES $9.95 JDR PART POWER -STRIP $9.95 NO CONFIGURATION JUMPERS PROGRAMS ALL 5V 27XXX EPROMS 15 AMP CIRCUIT BREAKER FROM 2716 TO 27512 6 RECEPTACLES READ. COPY OR VERIFY EPROM 6 FOOT POWER CORD UPLOAD DOWNLOAD INTEL HEX FILES PILOT SWITCH PROGRAMMER DRIVER USER MODIFIABLE WITH SURGE PROTECTION Kit includes PCB JOR PART P60 &except all components case & $99 4 $12.95 power supply

CALL FOR VOLUME QUOTES COPYRIGHT 1987 JDR MICRODEVICES 143 CIRCLE 182 ON FREE INFORMATION CARD 20 MEG HARD DISK DRIVE ON A CARD $349! TOTAL SYSTEM CONTROL FROM A SINGLE SLOT EASYDATA MODEMS SAVE THOSE VALUABLE SLOTS FOR SPECIALITY CARDS All models feature auto-dial/answer/radial on busy. Hayes compatible, power up sell MGT-MO.110$119.95 test, touchtone or pulse dialing, built-in speaker, PC TalkIll Communications HERCULES COMPATIBLE MONO. software, Bell Systems 103 & 212A lull or hall duplex and more. GRAPHICS. 720 384 PIXELS GAME PORT PARALLEL PORT & CLOCK CALENDAR INTERNAL SERIAL PORT INCLUDED, OPTIONAL 2nd SERIAL AVAILABLE SUPPORTS BOTH DS DO & OS QD EASYDATA-12H $79.95 USING DOS 3.2 OR HIGHER 1200 BAUD HALF CA _A EASYDATA-1213 $99.95 12011 BAUD 10' CA. QUALITY IBMCOMPATIBLE MOTHERBOARDS TURBO 4.77 / 8 MHZ $109.95 EASYDATA-2413 $179.95 2400 BAUD FULL CARL JDR PART # MCT-TURBO 4 77 OR 8 MHz OPERATION WITH 8088 2 & OPTIONAL 8087 2 CO PROCESSOR EXTERNAL DYNAMICALLY ADJUSTS SPEED DURING NO SOFTWARE INCLUDED DISKETTE OPERATION FOR MAXIMUM THROUGHPUT AND RELIABILITY CHOICE OF NORMAL TURBO MODE OR EASYDATA-12D $119.95 SOFTWARE SELECT PROCESSOR SPEED '.'00 BAUD STANDARD MOTHERBOARD $97.95 JDR PART x MCI X TMB EASYDATA-24D $219.95 L 80286 6 / 8 MHZ $379.95 JDR PART #: MCT-ATMB 8 SLOT 12 EIGHT BIT. 6 SIXTEEN BITI AT MOTHERBOARD MCT DISPLAY CARDS HARDWARE SELECTION OF 6 OR 8 MHz

1 WAIT STATE RESET SWITCH. FRONT PANEL LED MCT-EGA $149.95 INDICATOR AND KEYLOCK SUPPORTED lIX$Ir IBM COMPATIBLE. PASSES IBM EGA DIAGNOSTICS SOCKETS FOR 1 MB OF RAM AND 80287 ON COMPATIBLE WITH IBM EGA. COLOR GRAPHICS BOARD AND MONOCHROME ADAPTORS ON BOARD BATTERY BACKED CLOCK TRIPLE SCANNING FREQUENCY FOR DISPLAY OPERATES WITH PCDOS OR MSDOS ON EGA, STANDARD RGB OR HIGH RES OLUTION MONOCHROME MONITOR FULL 256K OF VIDEO RAM ALLOWS 640 350 PIXELS IN 16 OF 64 COLORS r IBM COMPATIBLE IBM COMPATIBLE LIGHT PEN INTERFACE 31/2" FDD KIT FLOPPY DISK DRIVE MCT-CG $49.95 JDR PART FDD-3 5 KIT JDR PART FDD 360 COMPATIBLE WITH IBM COLOR GRAPHICS STANDA,- 720K FORMAT. DOS 3.2 COMPATIBLE GOOD QUALITY DRIVES SHORT SLOT CARD USES VLSI CHIPS TO ALLOWS DATA INTERCHANGE WITH BY MAJOR MANUFACTURERS SUCH AS INSURE RELIABILITY NEW IBM MACHINES OUME. TANDON 6 CDC SUPPORTS RGB. COMPOSITE MONOCHROME MOUNTING HARDWARE FOR 5' 4" SLOT 5'." HALF HEIGHT DS DD & COLOR AND AN RF MODULATOR OUTPUT BOTH AT & XT VERSIONS AVAILABLE 360K STORAGE CAPACITY 48 TPI 320 x 200 COLOR GRAPHICS MODE 640 a 200 MONOGRAPHICS MODE LIGHT PEN INTERFACE $149.95 $69.95 MCT-MGP $59.95 COMPATIBLE WITH IBM MONOCHROME AND HERCULES GRAPHICS STANDARDS SHORT SLOT CARD USES VLSI CHIPS 70 IBM XT STYLE NICKEL EXPRESS INSURE RELIABILITY PARALLEL PRINTER PORT. CONFIGURABLE AS COMPUTER CASE LPT1 OR LPT2 PC/ XT SPEED UP KIT 720 a 348 GRAPHICS MODE AN A TTRAC T.. LOTUS COMPATIBLE A HINGED LID I, r FROM RIM ELECTRONICS CAN RUN WITH COLOR GRAPHICS CARD IN COMPATIBLE MO THERE1()A THE SAME SYSTEM INCREASE THE SPEED OF YOUR PC X 4 OR CLONE BY 67°. OR MORE' SIMPLE NO SLOT INSTALLATION SOFTWARE OR HARDWARE SPEED SELECTION 8 MHz V20 PROCESSOR & MCT DEVELOPMENT TOOLS SOFTWARE INCLUDED SELECT FOR 3 TURBO FREQUENCIES MCT-PAL PAL PROGRAMMER EXTERNAL RESET SWITCH $269.95 OPTIONAL 8088 8 MHz PROCESSOR ONE ARRAY LOGIC CHIP CAN REPLACE 4-5 TTL ICs SWITCH CUTOUT ON SIDE FOR PC XT AVAILABLE PROGRAMS 20 & 24 PIN PALS FROM TI. STYLE POWER SUPPLY KIT INCLUDES CABLING. TEST CLIP NSC & MMI CUT-OUT FOR 8 EXPANSION SLOTS AND SWITCHES EASY TO USE MENU DRIVEN SOFTWARE INCLUDES SPEAKER ALLOWS PROGRAMMING. VERIFICATION ALL HARDWARE INCLUDED READING. MAP BUILDING & BURNING THE SECURITY FUSE READ AND SAVE BURN PROFILES IN $69.95 JEDEC FORMAT ON YOUR DISK PLEASE NOTE $34.95 Certain early PCs may nor run at 8 MHz - CUM. STARTER KIT $4995 KT STYLE SLIDE TYPE CASE $39.95 these machines may be switched to one of the slower speeds AT STYLE SLIDE TYPE CASE $89.95 666 MH, 40, 737 MHz - 55% 8 0 MH, 67% MCT-MP MICROPROCESSOR PROGRAMMER h. A $199.95 PROGRAMS 8741;2,8/9 PROCESSOR CHIPS EASY TO USE MENU DRIVEN SOFTWARE SUPPORTS READ. WRITE, BLANK CHECK AND VERIFY OPERATIONS IBM COMPATIBLE KEYBOARDS PORT ADDRESS SELECTION IS USER CONFIGURABLE MCT-5060 $59.95 SAVE AND RESTORE PROGRAM IMAGES IBM AT STYLE LAYOUT ON DISK SOFTWARE AUTOSENSE FOR XT OR AT INCLUDES SOFTWARE FOR STANDARD COMPATIBLES HEX AND INTEL HEX FORMATS EXTRA LARGE SHIFT & RETURN KEYS LED INDICATORS FOR SCROLL. CAPS & NUMBER LOCK MCT-EPROM EPROM PROGRAMMERS $ 129.95 AUTO REPEAT FEATURE PROGRAMS 27xx AND 27xxx SERIES EPROMS UP TO 21512 SUPPORTS VARIOUS MANUFACTURERS MCT-5339 $79.95 ORMATS WITH 12.5. 21 AND 25 VOLT IBM ENHANCED STYLE LAYOUT PROGRAMMIMG SOFTWARE AUTOSENSE FOR XT OR AT MENUDRIVEN SOFTWARE ALLOWS COMPATIBLES F ASY MANIPULATION OF DATA FILES 12 FUNCTION KEYS SPLIT OR COMBINE THE CONTENTS OF EXTRA LARGE SHIFT & RETURN KEYS SEVERAL EPROMS OF DIFFERENT SIZES LED INDICATORS FOR SCROLL, CAPS & READ. WRITE, COPY, ERASE CHECK AND NUMBER LOCK VERIFY WITH EASY ONE KEY SELECTION AUTO REPEAT FEATURE INCLUDES SOFTWARE FOR STANDARD SEPARATE CURSOR PAD HE X AND INTEL HEX FORMATS MCT-5150$49.95 MCT-5151$69.95 4GANG PROGRAMMER $18995 XT STYLE LAYOUT KB515I - EQIUVALENT JO GANG PROGRAMMER $29995 4

MCT PRODUCTS CARRY A ONE YEAR WARRANTY COPYRIGHT 1987 JDR MICRODEVICES 144 CIRCLE 183 ON FREE INFORMATION CARD MODEM BAUD $7995 WITHRSOBFrWARE MODEMBAUD$17995 MULTIFUNCTION CARDS FROM MODULAR CIRCUIT TECHNOLOGY MCT-MF $79.95 ALL THE FEATURES OF ASTS SIX PACK PLUS AT HALF THE PRICE, SS?Seagate 0-348K DYNAMIC RAM USING 4164s INCLUDES SERIAL PORT. PARALLEL PRINTER PORT, GAME CONTROLLER PORT AND 'Nat CLOCK CALENDAR '1141`..- HALF HEIGHT HARD DISK DRIVES SOFTWARE FOR A RAIVIDISK, PRINT SPOOLER AND CLOCK CALENDAR 40 MB 60 MB Model ST -251 5'," half height Model ST -277 57." half height MCT-ATMF $139.95 FAST 40ms access time FAST 40ms access time (RLL) ADDS UP TO 3 MB OF 1 BIT RAM TO THE AT USER EXPANDABLE TO 1.5 MB OF ON -BOARD MEMORY (NO MEMORY INSTALLED) FLEXIBLE ADDRESS CONFIGURATION INCLUDES SERIAL PORT AND PARALLEL PORT OPTIONAL PIGGYBACK BOARD PERMITS $469 $649 EXPANSION TO 3 MB ATMF-SERIAL 2nd SERIAL PORT $2495 MCT-ATMF-MC $2905 PIGGYBACK BOARD (ZERO K INSTALLED) HALF HEIGHT HARD DISK SYSTEMS MCT-M10 $79.95 A PERFECT COMPANION FOR OUR MOTHERBOARL 2 DRIVE FLOPPY DISK CONTROLLER 20 MB 30 MB INCLUDES SERIAL PORT. PARALLEL PORT, GAME PORT AND CLOCK CALENDAR WITH BATTERY BACK-UP SOFTWARE FOR A RAMDISK, PRINT SPOOLER AND CLOCK CALENDAR $299 $329 MID -SERIAL 2nd SERIAL PORT $15115 Systems include hall height hard disk drive, hard disk drive controller, cables and instructions. All drives are pre -tested and warranted for one year. MCT-I0 $59.95 USE WITH MCT-FH FOR A MINIMUM OF SLOTS USED SERIAL PORT ADDRESSABLE AS COM1, COM2, DISK CONTROLLER CARDS COM3 OR COM4 rte.,"._ IT PARALLEL PRINTER PORT ADDRESSABLE AS FROM MODULAR CIRCUIT TECHNOLOGY LPTI OT LPT2 (.378 OR .278) CLOCK CALENDAR WITH A BATTERY BACK UP MCI-FDC $29.95 10 -SERIAL 2nd SERIAL PORT 81595 QUAL T Y DESIGN OFFERS 4 FLOPPY CONTROL IN A SINGLE SLOT INTERFACES UP TO 4 FOOs TO AN IBM PC OR COMPATIBLE INCLUDES CABLING FOR 2 INTERNAL DRIVES MCT-ATIO $59.95 USES STANDARD DB37 CONNECTOR USE WITH MCT-A TFH FOR A MINIMUM OF SLOTS USED FOR EXTERNAL DRIVES SUPPORTS BOTH DS DD AND OS GD SERIAL PORT ADDRESSABLE AS COM1, COM2, WHEN USED W DOS 3.2 OR JFORMAT COM3 OR COMA PARALLEL PRINTER PORT ADDRESSABLE AS LPTA OR LPTB 1.378 OR .278) GAME PORT two USES 16450 SERIAL SUPPORT CHIPS FOR HIGH MCT-HDC $79.95 SPEED OPERATION IN AN AT stol HARD DISK CONTROL FOR WHAT OTHERS CHARGE FOR FLOPPY CONTROL ATIO-SERIAL 2nd SERIAL PORT $249$ IBM XT COMPATIBLE CONTROLLER SUPPORTS 16 DRIVE SIZES INCLUDING 5. 10. 20. 30 & 40MB OPTIONS INCLUDE THE ABILITY TO DIVIDE 1 LARGE DRIVE INTO 2 RAM CARDS SMALLER. LOGICAL DRIVES INCLUDES CABLING FOR 1 INTERNAL FROM MODULAR CIRCUIT TECHNOLOGY DRIVE MCT-RAM $59.95 MCT-RLL A CONTIGUOUS MEMORY SOLUTION FOR YOUR SHORT OR REGULAR SLOT $119.95 GET UP TO 50Ao MORE STORAGE SPACE ON YOUR HARD DISK SHORT SLOT. LOW POWER PC COMPATIBLE DESIGN INCREASES THE CAPACITY OF PLATED CAN OFFER UP TO 576K OF ADDITIONAL MEDIA DRIVES BY 50", MEMORY RLL 2.7 ENCODING FOR MORE USER SELECTABLE CONFIGURATION RELIABLE STORAGE AMOUNTS OF 192, 384, 512. 256 8 576K. TRANSFER RATE IS ALSO 50.0 FASTER USING COMBINATIONS OF 64 & 256K RAM 750K sec vs 500K sec USE WITH ST 238 DRIVE TO ACHIEVE 30- MB IN A HALF HEIGHT SLOT MCT-EMS $129.95 2MB OF LOTUS INTEL, MICROSOFT COMPATIBLE MEMORY THE XI MCT-FH $139.95 CONFORMS TO LOTUS INTEL EMS STARVED FOR SLOTS, SATISFY IT WITH THIS TIMELY DESIGN USER EXPANDABLE TO 2MB INTERFACES UP TO 2 FDDs & 2 HDDs USES 64K OR 256K DYNAMIC RAM CABLING FOR 2 FDDs & 1 HDD (NO MEMORY INSTALLED) FLOPPY INTERFACE SUPPORTS BOTH USE AS EXPANDED OR CONVENTIONAL DS DD & DS QD WHEN USED WITH MEMORY. RAMDISK OR SPOOLER DOS 3.2 OR JFORMAT SOFTWARE INCLUDES EMS DEVICE DRIVERS. ALL POPULAR HOD SIZES ARE PRINT SPOOLER AND RAMDISK SUPPORTED. INCLUDING 5. 10, 20, 30 & 40MB CAN DIVIDE 1 LARGE DRIVE INTO 2 MCT-ATEMS $139.95 SMALLER. LCGICAL DRIVES CAN BE USED FOR CONVENTIONAL, EXPANDED OR EXTENDED MEMORY A FINE EXAMPLE OF FLEXIBILITY: MCT-ATFH $149.95 OFFERS EXTENDED (AT MEMORY) OR 11+11 1-11t4"" FLOPPY AND HARD DISK CONTROL IN A TRUE A I' UI EXPANDED (LIM EMS) MEMORY AS WELL AS III 11111141u:1:1.,Kr THE ABILITY TO FILL OUT CONVENTIONAL1640K) AT COMPATIBLE, CONTROL UP TO 2 MEMORY 360K 720K OR 1.2MB FDDs AS WELL Will FI131)13-4Ar-x . () -x 2 MEGABYTE CAPACITY IN A SINGLE SLOT 11111111 1114limin AS 2 HDDs USING THE AT STANDARD RAMDISK, PRINT SPOOLER AND LIM EMS CONTROL TABLES Alf SOFTWARE INCLUDED ) a a %N.. l SUPPORTS AT STYLE FRONT PANEL SPECIAL MEMORY MAP ANALYSIS INCLUDED LED TO INDICATE HD ACTIVITY 16 BIT BUSS PROVIDES RAPID DATA MCT-ATEMS-MC $3405 TRANSFERS PIGGYBACK BOARD (ZERO K INSTALLED) FULLY SUPPORTED BY AT BIOS

110 Knowles Drive, Los Gatos, CA 95030 JDR MicrodeviceS Toll Free 800-538-5000 (408) 866-6200 FAX (408) 378-8927 Telex 171-110 THE JDR MICRODEVICES LOGO IS A REGISTERED TRADEMARK OF JDR MICRODEVICES. JDR INSTRUMENTS AND JOB MICRODEVICES ARE -RADEMARKS OF JDR MICRODEVICES IBM IS A TRADEMARK OF INTERNATIONAL BUSINESS MACHINES CORPORATION 145 CIRCLE 184 ON FREE INFORMATION CARD COPYRIGHT 1987 JDR MICRODEVICES MODEM 121 $7995 INIIIrSIIEFPTEIWARE MODEM Mg $17995 BARGAIN HUNTERS CORNER PAGE WIRE WRAP WIRE WIRE WRAP PROTOTYPE CARDS PRECUT ASSORTMENT FR -4 EPDXY GL ASS LAMINATE IN ASSORTED COLORS $27.50 WITH GOLD-PLATED EDGE -CARD FINGERS 100,a, 5.5". 60". 6.5",1.0" 250,a 2.5" 4.5", 5.C' HYUNDAI 500ea, 3.0" 3.5", 4.C' SPOOLS 100 feet 54.30 250 feet37.25 500 feet $13.75 1000 feet 521.95 MONOCHROME Please specify color: Blue. Black, Yellow o. Red XT BOTH CARDS HAVE SILK SCREENED LEGENDS MONITOR AND INCLUDES MOUNTING BRACKET

EXTENDER CARDS IBM PR1 WITH .5V AND GROUND PLANE . . . . 527.95 * 12" NON -GLARE AMBER SCREEN IBM-PC $29.95 IBM- PR2 AS ABOVE W DECODING LAYOUT . . . . 529.95 * IBM COMPATIBLE TTL INPUT IBM -AT $39.95 AT * ATTRACTIVE CASE WITH TILT & IBM PRAT LARGE -5V & GROUND PLANES 529.95 SWIVEL BASE S-100 P100-1 BARE NO FOIL PADS 315.15 P100-2 HORIZONTAL BUS $21.80 P100.3 VERTICAL BUS $21.80 P100-4 SINGLE F011. PADS PER HOLE 322.75 ONLY $69.95 APPLE P500.1 BARE NO FOIL PADS 515.15

P500-3 HORIZONTAL BUS . . . 522.75 P500-4 SINGLE FOIL PADS PER HOLE 521.80 SPECIAL ENDS 10/31/87 7060.45 FOR APPLE Ile AUX SLOT 530.00 r SOCKET -WRAP I.D."" . .. FRAME STYLE. SLIPS OVER WIRE WRAP PINS . , : C SWITCHING POWER SUPPLIES IDENTIFIES PIN NUMBERS ON WRAP - ; TRANSFORMERS SIDE OF BOARD 12.6V AC CT AMP 95 PS -IBM $59.95 CAN WRITE ON PLASTIC. SUCH AS IC, 9-0 U 12.6V AC (11 -5 AMP / EC R IBM PC XT COMPATIBLE PINS PART, PCK. OF PRICE xi 12.6V AC Cr RAMP 10 95 135 WATTS 8 IDWRAP 08 10 25.2V AC CT AMP 95 1.95 4, 5./ 15/1. 124 4.2A 14 IDWRAP 14 10 1.954, 515, 12V 16 IDWRAP 16 10 1.95 5/ 5A 18 IDWRAP 18 5 1.95'.. DOE YEAR WARRANTY 20 IDWRAP 20 5 1.95 9^ 25 PIN D -SUB PS IBM 150 22 IDWRAP 22 5 1.95 Ai,. 24 IDWRAP 24 5 1.95....,, GENDER PS -IBM -150 $69.95 28 IDWRAP 28 5 1.95 FC R IBM PC XT COMPATIBLE 40 IDWRAP 40 5 CHANGERS '."-N,400V 150 WATTS PI EASE ORDER BY NUMRER OF1-95 11) WRAP 24 PACKAGES IPCK OF) $7.95 1 ?V 5.2A. 51/1,, 16A I. A 1 !V I..5A. -5V ( SA OFIE YEAR WARRANTY CAPACITORS DATARASE EPROM ERASER $34.95 ERASES 2 IN 10 MINUTES PS AT TANTALUM COMPACT NO DRAWER $89.95 1.011 15V .35 .47,4 35V 45 THIN METAL SHUTTER FC R IBM PC -AT COMPATIBLE 6.8 15V .70 1.0 35V 45 PREVENTS UV LIGHT 2M WATTS PS AT 10 15V .80 2 2 35V .65 I FROM ESCAPING MIL 54 o 22A, 121 8A 22 15V 1.35 4.7 35V .85 .5 .5A. -12V v, .5A .22 35V 40 10 35V 1.00 1 '"EAR WARRANTY DISC VI WATT RESISTORS /Oil 50V .05 680 50V .05 22 50V .05 00101 50V .05 S CARBON FILM ALL STANDARD VALUES PS -A $49.95 27 50V .05 .0022 50V 05 FROM 1 OHM TO 10 MEG. OHM USE TO POWER APPLE TYPE I'S A 33 50V .05 .005 50V .05 10 PCS 5,rekle 05 100 PCS same va/ue .02 SSTEMS, 79.5 WATTS 47 50V .05 .01 50V 07 50 PCS-.1.98 value .025 1000 PCS same value 015 7A, 12V(, 3A 68 50V .05 .02 50V .07 5/ 100 50V .05 .05 50V 07 -511.). .5A, -12V 0 .5A 220 50V .05 .1 12V 10 AF PLE POWER CONNECTOR 560 50V 05 .1 50V 12 RESISTOR NETWORKS SIP 10 PIN 9 RESISTOR 69 11-1559 MONOLITHIC SIP 8 PIN 7 RESISTOR 59 $34.95 .01,4 50V 14 14 50V 18 75 WATTS. UL APPROVED .047o4 .15 DIP 16 PIN 8 RESISTOR PS IS',8 50V 47;? 50V .25 1 09 -5/ 7A. -12V 3A DIP 16 PIN 15 RFFISTOR 1.09 1 TV 250rna. 5V 300ma ELECTROLYTIC DIP 14 PIN 7 RESISTOR .99 RADIAL AXIAL DIP 14 PIN 13 RESISTOR .99 25V .14 1,1 50V 14 r 2.2 35V .15 10 50V 16 BOOKSer STEVE CIARCIA MUFFIN FANS 4.7 50V .15 22 16V 14 3.15"SO 14 95 3 63" SO 14.95 10 SOV .15 47 50V .20 BIULD YOUR OWN 3.18" SQUARE 16 95 47 35V .18 100 35V 25 SPECIALS ON BYPASS CAPACITORS ZED COMPUTER 519.95 100 16V 18 220 25V .30 01 /ff f.ERAMIC DISC 100;$5.00 CIRCUIT CELLAR VOL 1 617.95 6' LINE CORDS 720 35V .20 470 50V .50 .01 iff MONOLITHIC 100/ 510.00 CIRCUIT CELLAR VOL 2 $18.95 2 conductor 39 3 conductor 99 470 25V .30 1000 16V .60 CIRCUIT CELLAR VOL 3 3 conductor w female socket 70 .1 Id CERAMIC DISC 100 56.50 618.95 1 49 2200 16V 2400 16V 73 CIRCUIT CELLAR VOL 4 s18.95 4700 25V 1 45 4700 16V 1.25 .1 IA MONOLITHIC L- 100 $12.50 CIRCUIT CELLAR VOL 5 419.95 FMI FILTER $4.95

WISH SOLDERLESS BREADBOARDS LITHIUM BATTERY AS 1,SF 0 INCLOCK CIFICIIITS 2 VOLUME SET PART TIE TERMINAL TIE BINDING DIMENSIONS DISTRIBUTION PRICE NUMBER POINTSSTRIPISI POINTS POSTS .

IL) WBU-D .38 x 6.50" 1 100 -- 2.95 iClir IC MASTER WBU-T 1.38 x 6.50" 630 6.95 THE INDUSTRY STANDARD WBU-204-33.94 x 8.45" 1 100 1260 2 17.96 WBU-204 5.13 x 8.45" 4 400 2 1260 3 24.95 WBU-208 8.88 9.06- 5 500 3 1890 4 79.95 *?! 3 VOLT BATTERY s.i 95 WBU-208 8.25 x 9.45" 700 2520 4 39.95 W1111.1-208 BATTERY HOLDER 51 49 $129.95 NEW STORE HOURS! M -F:9-7,SAT: 9-5 & SUN: 12-4 Visit our retail store located at 1256 S. Bascom Ave. inSan Jose, (408) 947-8881 PLEASE USE YOUR CUSTOMER NUMBER WHEN ORDERING TERMS Mimmum order $10.00. For shipping and handling include 52.50 for UPS JDR Microdevices Ground and :3.50 for UPS Air. Orders over 1 lb. and foreign orders may require additional shipping chages-please contact our sales department for the amount. CA residents 110 Knowles Drive, Los Gatos, CA 95030 must incluck applicable sales tat. All merchandise is warranted for 90 days unless otherwise staled. Pnces are subject to change without notice. We are not responsible tor Toll Free 800-538-5000 (408) 866-6200 typographical errors. We reserve Ste nght to limit quantities and to substitute manufacturer. All me^chandise subject to pnor sale. A lull copy of our terms is available upon FAX (408) 378-8927 Telex 171-110 request. Items pictured m2y only be representative. COPYRIGHT 1987 JDRMICRODEVICES THE JDR MiCRODE VICES LOGO IS A REGISTERED TRADEMARK OF JDR MICRODE VICES. JON INSTRUMENTS AND JDR MICRODEVICES ARE TRADEMARKS OF JDR MICRODEVICES 146 IBM IS A TRADEMARK OF INTERNATIONAL BUSINESS MACHINES CORPORATION. APPLE IS A TRADEMARK OF APPLE COMPUTER. CIRCLE 18E ON FREE INFORMATION CARD SEND FOR *QUALITY PARTS *DISCOUNT PRICES #FAST SHIPPING! FREE 1987 CATALOG OUR NEW MAILING ALL ELECTRONICS CORR ADDRESS IS: P.O. BOX 567 VAN NUYS, CA 91408 800-826-5432

BLACKLIGHT ASSEMBLY ELECTRET CONDENSER MIKE LIGHT ACTIVATED LED'S MOTION SENSOR Standard Jumbo Diffused T 1-3/4 This device Size mouser* 25LM044 Highly contains a 010 RED 10 for $1.50 sensitive mini microphone. photocell CATS LED -1 100 for $13.00 6" wire leads. 0.39" dai. which senses 1000 for $110.00 X 0.27" high. Omni directional. sudden change operates on 2-10 Vdc @ less in ambient GREEN 10 for $2.00 CAT* LED -2 100 for $17.00 Complete, than 1 mA. 1K impedance. 50 to light. Could functioning 8 K Hz range. be used as a door amnuncialor 1000 for $150.00 CATS MKE-1 $1.00 EACH or modified to trigger other assembly includes ballast,. YELLOW on -off switch, power cord, sockets devices. 5 1/2" X 4" X 1". 10 for $2.00 operates on 6 Vdc. Requires CATS LED -3 100 for $17.00 and F4T5-BL blacklight. Mounted on NI -CAD CHARGER / TESTER 1000 for $150.00 a7 1/8" X3 1/8" metal plate. Use 4 AA batteries (not included). for special effects lighting or DELUXE universal QM CAT* LSMD $5.75 per unit FLASHING LED lisre, erasing EPROMS. charger and tester w/ built in flashing circuit CATS BI.TA510.00 EACH for almost every operates on 5 Volts... size NI -CAD battery TrIIRD TAIL LIGHT available. RED $1.00 each SWITCHING POWER SUPPLY CAT* UNCC-N $15.00 each Sleek high-tech CAT* LED -4 10 for $9.50 lamp assembly. Compact, well regulated switching RECHARGEABLE Red lens is 2 3/4" power supply designed to power Texas NI -CAD BATTERIES GREEN $1.00 each X 5 1/2" mounted on CATS LED -4G 10 for $9.50 Instruments computer equipment. AAASIZE $2.25 a 4" high pedestal INPUT: 14-25 vac @1 amp AA SIZE $2.00 with m, -down swivel BI - POLAR LED ----ID OUTPUT: +12 vdc @ 350 ma. AA wan solder tab $2.20 adjustment. Has +5 vdc @ 1.2 amp C SIZE 12V 120CmAH $4.25 12Vreplaceablebulb. Lights RED one direction, -5 vdc @ 200 ma. SUB -C SIZE solder tab $4.25 CATS TLB $3.95 each GREEN the other. Two lead. SIZE:4 3/4" square. 0 SIZE 1 2V 1200mAH CATS LED -6 2 for $1.70 Includes 18 Vac @1 amp wall transformer designed LED HOLDERS to power this supply. SOUND EFFECTS BOARD RELAYS TRANSISTORS 2N2222A Two Piece CATS PS -TX $5.00 / set P.C. board with 2 1/4" speaker, 12 VDC-4PDT Holder a is 10 for $45.00 for $1.00 2 LEDs, IC, battery snap, other P.C. mount components 2 3/8" X 3'. 5 amp contacts PN2222A CATO HLED 10 for 65c when switch is pushed 150 ohm coil SLIM LINE FAN board beeps and leds 4 for $1.00 Size: 1 1/4" X CLIPLIGHTE TOY011 TF92115A New 115 Vac light.Operates 1 3/4" X 7/8" 2N2904 cooling fan.3 5/8" square on 9V battery CATS 4PRLY-12PC $3.50 LED HOLDER X 1" deep. Metal housing. (not included). 1?: 10 for $30.00 3 for $1.00 Makes L.E.D. 5 blade impeller. CATS ST -3 $1.25 each 2N2905 look like a 10 AMP SOLID STATE fancy indicator. CATII SCFE-115 $8.50 each Control: 3-32 Vdc 3 for $1.00 10 for $75.00 VENTED PROJECT CAS Load: 10 AMPS, 2N3055 CLEAR CATS HLDCL-C 120 Vac RED CATS HLDCL-R Bopla *BO 718L $1.00 each 1 mA METER Size: 2 1/2' X GREEN CATII HLDCL-G Vented top and 3/4' X 7/8" Modutec 0-1 mA YELLOW NiTHIMCL-Y bottom. Black CATS SSRLY-10A $9.50 PN3569 signal strength 4 of one color $1.00 plastic with 10 for $85.00 10 for $1.00 meter with KLM logo. removable end panels. 1/4" X 1 3/4" X 7/8' deep. CATS MET -2 $2.00 each 4." X 8 1/2" X 3" COMPUTER GRADE TRANSFORMER SWITCHES CATS MB -718 $12.50 each MINIATURE TOGGLE CAPACITORS SWITCHES 2 K 10 TURN 1,400 MFD 200 VDC rated 5 Amps PUSHBUTTON PHONE 2" dia.X 3" high Mulit-turn pot CATS 3G-1420 $2.0C S.P.D.T. (ON -ON) Spectra -phone Model S OP -1 Spectrol 1 MOD 534-7161 non -threaded 1 piece telephone with CATS MTP-10-2 $5.00 each 7,500 MFD 200 VDC bushing rotary (pulse) output. 3" dia. X5 7/8" h. 5.6 Volt - 750 ma P.C. mount. Operates on most rotary or CAT* CG -75 $4.00 6-12 VDC MOTOR CAT, TX -56 $3.00 CATS MTS-40PC touch tone systems. Features 22,000 MFD 25 VDC 75c each lastminute redial and mute MabuchiI RS -550S 12 V.c.t. - 1 amp 10 for $7.00 button. Includes coil cord Permanent magnet motor. 2" dia. X 4 3/4" h. CATS TX -121 $4.00 S.P.D.T. (ON -ON) with standard modular plug. 7/16" dia X 2 1/4' long. CATS CG -22 $2.50 IVORY. 2,600 RPM @ 6 Vdc - 200 mA 1219.c.t. -2 amp Solder lug 72,000 MFD 15 VDC terminals. CATS PHN-1 $8.50 EACH 5,300 RPM @ 12 Vdc 2' dia. X 4 3/8" h. CATS TX -122 $4.85 FOR $15.00 CATO DCM-7 $3.00 each CATS MTS-4 CATS CG -130 $3.50 12 V.c.t. -4 amp $1.00 each 10 for $9.00 48 KEY ASSEMBLY XENON FLASH TUBE CATk TX -124 $7.00 VIC 20 MOTHERBOARD 18 Volt - 650 ma ELP.D.T. (ON -ON) 3/4" long X 1/8" dia. Solder lug CATp TX -186 $2.00 CATS FLT-_ 2 for $1.00 terminals 10 for $18.00 CATS MTS-8 POLARITY ASO 24 V.c.t. - 1 amp $2.00 each 10 for $19.004 SWITCH bto4 CAT4 TX -241 $4.85 NEW T.1. KEYBOARDS. MINI PUSH BUTTON Designed to control an 24 V.c.t. -2 amp originally used on external coaxial relay S.P.S.T. computers, these CAT* TX -242 $6.75 on a satellite T.V. momentary.nnew keyboards contain system. Ideal for parts. 48 S.P.S.T. mechanical 26 IC's including 6502A and 6560. 24 V.c.t. -3 amp Push to make. Contains a5 Vdc relay 1/4" bushing. switches. Terminates 2 ea. 6522, 2 ea. 8128,2 ea. 901486, CATS TX -243 $9.50 and many other parts on Red button. to 15 pin connector. ea. 2114. Not guaranteed but great a P.C. board. Frame 4" X 9" 24 V.c.L -4 amp CATS MPB-1 35c each for replacement parts or experimentation. CATS RDPS $1.75 each 10 for $3.00 CATS KP-48 $3.50 each CAT 5 VIC-20 $15.00 each 10 for $15.00 CAT; TX -244 $11.00

SOUND AND VIDEO TELEPHONE COUPUNG STORES MAIL ORDERS TO: TOLL FREE MODULATOR TRANSFORMER LOS ANGELES ALL ELECTRONICS P.O.BOX 567 800-826-5432 TIS UM1381-1. Designed for STANCOR INFO:(818) 904-0524 use with T.I. computers. Can 905 S.VERMONT AVE. VAN NUYS, be used with video cameras, TTPC-8 LOS ANGELES, CA CA 91408 FAX:(818) 781-2653 games or other audio/video QUANTITIES LIMITED 600 ohms c.t. 90006 TELEX MINIMUM ORDERS SIO.OG =lir! sources. Built in A/B switch enables user to switch from to 600 ohms c.t. (213) 380-8000 TWX-101010163 CALIF. ADD SALES TAX P.C. board mount. T.V. antenna without discon- VAN NUYS ALL ELECTRONICS USA: 1.3.00 SHIPPING 3/4" X 5/8" X 3/4" NO C.0.0.! nection. Operates on channel 6228 SEPULVEDA BLVD. Foreign Customers FOREIGN ORDERS: 3 or 4. Requires 12 Vdc. Hook Send $1.50 postage up diagram included. CATS TCTXS VAN NUYS, CA 91411 INCLUDE SUFFICIENT $2.50 each (818) 997-1806 for FREE Catalog!! SHIPPING CATS AVMOD $5.00 each

CIRCLE 107 ON FREE INFORMATION CARD 147 nde ail -Order Electronics ELECTRONICS FOR415-592-8097 ORDERS ONLY ALL415-592-8121 OTHER INQUIRIES

NEC V20 & V30 CHIPS MICROPROCESSOR COMPONENTS SATELLITE TV Replace the 8086 or 8088 in Your IBM-PC and MISCELLANEOUS CHIPS Pan pft. Increase Its Speed by up to 40%'Arc. 6500 6800 68000 Cont. 8000 SERIES Cont. DESCRAMBLER CHIP Part No. Price Part No. Puce Part No Proce UPD70108-5(5t4Hz) V20 Chip $ 8.75 0765AC 495 6845 395 8228 295 supply the basic sync lunctrons for either color ormoor. UP070108-8 (8MHz) V20 Chip W1392113. 695 6850 195 8237-5 495 chrome 525 linr560Hr interlaced and camera V1Cif, rr,ord. $10.75 r.. UP070108-10 (10MHz) V20 Chip $29.95 Zit MM. MR MEE 6852 149 8243 225 COLOR BURST GATE 8 SYNC Z80 125 MC680001.8 11.95 82504 649 AI OW STABLE COLOR OPERATION UPD70116-8(8MHz) V30 Chip $13.75 Z80-CTC 179 MC68000LIO 1395 82508 (For IBM) 695 MM5321N UPD7011 6-10 (10MHz) V30 Chip $29.95 ZOO -DART 495 MC68010110 49.95 8251A 189 $11.95 Z80 P10 1.79 MC68020111C1213169.95 8253-5 1.95 2.80A 169 MC68881RC12A 14995 8254 495 INTERSIL Also Available! 7400 280A-CTC 1 79 5000 SERIES 8255A-5 189 Part No. 1-9 10+ Pert No. 1.9 10. Z80A- DAR T 4.95 8031 . .. 3.95 8257-5 195 74HC HI -SPEED CMOS ZBOA-P10 80031 9.95 8259-5 2.25 '400 29 19 7485 65 .55 1 69 Part No Prie Part No Pr Z80A-S/0/0 8035 195 8272 495 '402 .29 19 7486. .45 .35 5.75 8073 '404 .29 .19 7489. Z806 3 49 9 95 8279-5 2.95 7441000 '4HC175 2 05 1.95 8080A.. ..295 8741 995 /405 35 257490 .49 .39 Z80B-CTC 395 7411002 '41-10221 8085A . .. 2.49 8748 (25V) 795 /406 39 29 7493 .45 .35 2806-1710 4.29 74HC04 '4FIC240 8086 595 8748H IHMM112110 ... 9.95 7411008 '4410244 '407 39 29 74121 45 .35 111500/SS00/611000 SER. 8086-2 695 8749 995 74HCIO . . '4140245. '406 35 25 74123. 55 .45 6502. 2.65 8087(5MHz) 129.95 8751 39.95 9, '410 .29 .19 74125 55 65CO2 (CMOS) 8755 14.95 74HC14 74HC253 5" A5 8.95 8087-2(8MHz) 169.95 7411030 '414 49 39 74126. .69 59 6520 195 8088 649 DATA ACQUISITION 2974HC259 8" '416 39 2974143 3953.85 6522 395 8088-2 74)4032 2974410273 9, 895 ADC0804LCN. 3.19 7411074. '417 .39 29 74150. 135125 6532 6 49 8116 495 ADC0808CCN 5.95 39 74HC373 9" '420 35 25 74154. 135 1.25 6551 449 8155 249 ADO3809CCN 395 74HC75 .39 74110374 .9" '430 35 25 74158...1.59 149 650802 (CMOS)... 19.95 8155-2 349 ADC0816CCN 1195 74HC76 4574HC595 12" "432 39 .29 74173 .85 75 6800 195 8156 395 ADC I 205CCJ-1 1995 74HC85 .79 74HC688. 9" "438 .39 2974174 59 49 6802 3 95 8202. 595 DAC0608LCN 195 74HC86 .39 74HC943 895 /442 55 .45 74175 59 49 6810 1 25 995 DACI008LCN. 495 74HC123 89 741-104040 9" /445 79 6974176 6821 175 8212 149 AY 3 10150 495 74110125 .49 74H04049 5" 99 .89 6840 446 89 .79 74181 195 1.85 395 8224 225 AY -5-1013A 295 74HC132 .....69 741104050 5" /447 89 .79 74189 195 1.85 74HC138 49 7411C4060 9,.. 7448 205 1.95 74193 79 .69 74HC139 .49 741-04511 1 2, 7472 89 .79 74198. 1851/5 74HC 154 1.49 741-104514 1 79 7473 39 .29 74221 99 .89 MICROPROCESSOR SALE! 74HC1 63 65 74110,4538 89 74W0174 5,1 7474 39 .29 74273 195 1.85 Part No Rice 7.1H04541 7475 49 3974368 65 .55 '476 45 35 74367 65 55 MC68000L8 16 -Bit MPU (8MHz) $ 11.95 74HCT - CMOS TTL MC68000L10 74611. ;491.1 1 SO 74LS 16 -Bit MPU (10MHz) $ 13.95 74HC102 29 74HCT157 10' -41-509 t.tr MC6800010 2 16 -Bit MPU (12MHz) $ 17.95 74HCTO4 29 74HCT 174 6" '4LS02 29 S166... 99 .89 74HCTO8 29 74HCT175 6'' MC68008L8 32 -Bit MPU (8 -Bit Data Bus) $ 19.95 74HCT10 29 74HCT240 95 74LSO4 35 . 5173 59 .49 74LSO5 35 25 '4LSI74 49 39 74HCT32 29 74HCT244 MC68010L10 16 -Bit MPU (10MHz) $ 49.95 74HCT74 74LS06 I 09 9974LS175 49 .39 49 74HCT245 1 I" 74LS07 109 .99 74LSI 89 4594.49 MC6802ORC12B 32 -Bit MPU (12MHz) $169.95 74HCT86 49 74HCT373 741.508 29 .19 74L.S191 59 .49 MC68701 8 -Bit EPROM Microcomputer . $ 14.95 74HCT138 59 74HCT374 74L510 29 .19 74LSI 93 79 69 ,ILS14 49 39 74L.5221 69 59 MC68705U3L 8 -Bit EPROM Microcomputer . $ 10.95 74C- CMOS 74LS27 35 25 74LS240 69 59 MC68881RC12A Floating Point Co -processor$149.95 740.00 29 74C I 74 746.530 29 .19 74LS243 69 .59 74002 29 740175 741.532 35 25 74LS244 .69 59 74004 29740221 741.542 1 7" 49 39 7415245 89 .79 COMMODORE CHIPS 74008 35 740240 1 7" 74LS47 99 89741.5259 99 .89 DYNAMIC RAMS 74010 35 741-573 Pert No. Price Pert No. Price 740244 17" 39 .29 74LS273 89 /9 74014 59740373 1 91. 74LS74 35 25 74LS279 49 .39 4116-15 16,384 x 1 74032 35740374 1 9" 74LS75 39 (15005) .89 W01770 11.95 29 741.5322 405 395 4128-20 131.072 x 1(2000) (Piggyback) 325 74074 59740912 8 9' 74LS76 55 .45 74LS365 49 .39 4164-120 74085 149740915 I25 74LS85 59 .49 65.536 x 1 (120815) 1 75 513052P 2.49 74LS366. 49 39 4164-150 65,5364 1 74086. 35740920 65' 74LS86 35 25 741_5367 49 39 (15O0) 125 6502 4164-200 65,536 x 1 (2000s) .99 2.65 74089 549740921 6 9' 74LS90 49 .39 74LS368 .49 .39 74090 99740922 3 9, 741.593 TMS4416-12 16384 x 4 (12005) 3 49 6504A 1.95 49 39 74LS373 79 .69 74C154 295740923 3 9' 741.5123 59 49 74LS374 79 8118 16.384 x 1 (12005) 49 .69 6507 4.39 740173 . 1 05 740925 5"' 74LS125 49 .39 74LS393 89 .79 41256-120 262.144 x 1(12O0) 3.95 74LSI 38. . 49 39 74LS590 605 5.95 41256-150 262.144 x 1(1500) 325 6510 9.95 74LS139 49 741 c..8?4 50464-15 65.536 x 4 (15055) 14464) 495 LINEAR 39 205 1.95 6520 1.95 741.51 54 109 99 74LS629 295 2.85 511000P-10 1,048.576 x 1(1000) 1 Meg. 24.95 DS00260N 1.95 LM1458N 3" 74LSI 57 45 .35 74LS640 I 09 99 514256P-10 262,144 x 4 (10005) 1 Meg 2995 6522 3.95 TL074CN 1.19 LM1488N 74LSI 58 45 35 74L.S645 1 09 99 TL0840N 99 DS14C88N (CMOS)1 19 74LS163 59 .49 741.5670 109 99 STATIC RAMS 6525 4.95 AF100-1CN 895 LM1489N 4" 74LS164 49 74L5688 239229 2016-12 2048 x 8 (1200) 169 LM307N .45 DS14C89N (CMOS) I.19 2018-45 2048 x 8 (45ns) 695 6526 14.95 LM309K 1 25 LM1496N 8" 2102-2L 1024 x 1 (250ns) Low Power 1 95 6529 2.95 LM3 II N 45 MC1648P 3 4, 74S/PROMS* 2114N 1024 x 4 99 LA43177 .79 LM1871N 196 74505 LM318N 99LM1872N 195 1 49 2114N -2L 1024 x 4 (20005) Low Power . 1 49 6532 6.49 74504 .189 LM319N 129 LM1896N 14" 1.69 21C14 1024 x 4(200ns) (CMOS) 49 6545-1 4.95 /4508 3. 5196 249 2149 1024 x 4(45ns) LM323K 395 ULN2003A. 7" ... 249 LM324N 39 XR2206 39' 74.510 2', '45240 1.49 5101 256x4 (450ns) CMOS 1 95 6551 4.49 74532 LM338K 495 X62211. ,. . 35 /4S244 1.49 6116P-3 2048 x 8 (15005) CMOS 1.89 /4574 45 745253 79 6560 10.95 LM339N 39X62243... 6116LP-3 2048 x 8 (15005) LP CMOS 195 LF347N 1.79 261$29, ,. 74585 1 79 7452877 I.49 62641P-12 6567 14.95 74586 49745288' 149 8192 x 8 (120ns) LP CMOS 425 LM348N 69 26LS31 745124 6264P-15 8192 x 8(1500) CMOS 349 LM35OT 2.95 261_532 ... 275 745373 1.49 6569 24.95 LF351N .15I 79 745374 6264LP-15 8192 x 8 (15Ons) LP CMOS 3 75 39 261_533 14" 1 49 6514 6572 LF353N 49LM2901N .39 79 745472' 295 1024 x 4(350ns) CMOS 3.49 8.95 43256-151. 32,768 x 8 (1500) Low Power 11.95 LF355N 79LM2907N 12, 6581 (12V) 14.95 LF356N 89LM2917N 18 CO 1.91. 74F EPIWRIS 6582 (9V) 14.95 LF357N 109MC3419CL 69', 74F5 29 74F139 69 TM52516 2048 x 8 (450 5) 25V..... 695 LM358N 49 MC3446N 16" 74E0.1 74E157 7%452532 4096 x 8 (4500) 25V 695 8360 14.95 LM360N 219 MC3450P 195 29 69 LM361N 17954034706 19' 74FUti 29 741193 295 TMS2532A 4096 x 8 (451315) 21V.. .. 595 8501 10.95 LM380N-8 74E10 7%452564 8192 x 8 (4500s) 25V 995 99 MC3471P 19'. 29 74F240 99 LM386N 3 89MC3479P 4 7, 74F32 29 74F244 99 TMS2716 2048 x 8(450ns) 3 Voltage 995 8502 7.95 LM387N 74F74 3974F253 1702A 256 x 8 (10s) 695 99 MC3486P 16" .69 8563 15.95 LM393N 39 MC3487P 16" 74F86 39 74F2R3 99 2708 1024 x 8(450ns) 495 LM399H 295LM3900N 4, 74F1313 69 74F374 99 2716 2048 x 8 (450n8) 25V. 3 75 8564 9.95 LF41 ICN 79LM3905N. 1 19 2716-1 2048 x 8(350 5) 25V 425 99 2048 x 8 8566 24.95 7L497ACN. 27016 (45005) 25V (CMOS) . 5.49 NE540H (05443H) ..;.492 LM3914NL 1 95 CD-CMOS 2732 4096 x 8(450ns) 25V 395 29LA43916N 195 CD4001 19 CD4076 59 8701 9.95 NE555V 2732A-20 4096 x 8 (2030) 21V , 425 XRL555 59NE5532 6, ( 134008 69 CD4081 25 2732A-25 4096 x 8 (25005) 21V 3 95 '8721 14.95 49NE5534 6" C D4011 19 CD4082 25 LM556N 27032 4096 x 8(45005) 25V (CMOS) . 5.95 NE558N 7805K (1.84340K-5) .. 129 CD4013 29 CD4093 35 2764-20 8192 x 8(200ns) 21V 425 8722 9.95 ,,,897812K (LM340K-12) .129 CD4016 29CD4094 89 LM565N .. 7815K (LM34018-15) . 12, 2764-25 8192 x 8(25005) 21V 3.75 '251104-04 10.95 LM567V ".79 00401 7 49C(340103 2.49 2764A-25 8192 x 8(250 s( 12.5V 395 78051 (LM3407-5) ...49 CD4018 59CD40107 49 318018-03 10.95 NE592N .89 78121 (LA43407-12) .,49 2764-45 8192 x 8(45005) 21V 295 LM741CN. 29 CD4020. 590040109 /9 27C64-15 8192 x 8(15005) 21V (CMOS) 6.49 78157 (LM340T-15) ..4.. 004024 49CD4510 69 318019-03 10.95 LM747CN 597905K (LAA320K-5) .. 1.3' 27128-20 16.384 x 8 (20005) 21V 695 MC1350P CD4027 35 C04511 69 27128-25 16.384 x 8 (2501s) 21V 595 318020-04 10.95 1.0979057 (LM320T-5) ..5" Casoaa MC1372P 19575472 5'. 29 C134520 75 27128A-25 16384 x 8 (25015) 125V 525 325302-01 10.95 (704040.. 65 CD4522 79 27C129-25 16384 x 8 (25005) 21V (CMOS) 695 MC1377P 2.2975477 8'. MC1398P 895 MC145106P 3.25 CD4049... 29004538 .79 27256-20 32,768 4 8 (20005) 125V 6.95 '325572-01 24.95 0(34050 29 004541 LM1414N 1.29MC145406P 295 .89 27256-25 32,768 x 8 (2500) 12.5V 649 '825100PLA" 15.95 004051... 04543 79 270256-25 32.768 4 8 (2500) 12.5V (CMOS) . 8.95 CD4052. 1)4553 495 27512-20 65,536 x 8 (2000) 12.5V 13.49 901225-01 11.95 IC SOCKETS CD4053. 04555 79 27512-25 65.536 x 8 (250 5) 12.5V 11.95 901226-01 11.95 Low Profile WIN V740 (Gold) Level 43 04063. 04559 795 68764 8192 x 8 (4500s) 25V 13.95 8LP. 11 8VVVV 59 C04066 04566 249 901227-03 11.95 14LP. 12 14WW 6',. C04067. )4583 89 EEPIIOMS 16LP 13 16WW D4584 901229-05 11.95 39 2816A 2048 at 8 (350ns) 5V Read/Write5.95 2419 .25 24WW 11' ' CD4070. 04585 119 2817A 20484 8 (350 5) 5V Read/Write7.95 *No specs. (bailable 28LP 27 280505 139 004071 . 25 MC14411P... 895 2865A 8192 x 8 (250ns) 5V Reacl/Wnte ..9.95 ..Note 825100PLA = 4OLP 29 40WVV 1 8 CD4072 25MCI 4490P.. 449 52813 (21V) 2048 x 8 (350 5) 5V Read Only 1.49 1117 (C-64) Soklertail Standard !Sold& Tml It Header Plug SOCkInS Also Available PARTIAL LISTING OVER 4000 COMPONENTS AND ACCESSORIES IN STOCK! CALL FOR QUANTITY DISCOUNTS

CIRCLE 114 ON FREE INFORMATION CARD Mail Order Electronics Worldwide

WorldwideSince 1974 QUALITY COMPONENTS COMPETITIVE PRICINGjameco PROMPT DELIVERY ELECTRONICS

INTRODUCING JAMECO'S NEW I Mein unEsErima General Purpose unlamm Solderless NEW! Prototype PC Boards COMPUTER KITS!! Jameco's IBM' AT Compatible Kit! Breadboard Sockets Wire Wrap EGA Monitor 7E5154 539905 Mini -286 6/8/10/12 MHz Kit! Component EGA Card Part No. DwritatiOn Price Testing JE1055 5179.95 (not included) JE1043 1.2M/360K Floppy Control. $ 49.95 Point -to - JE1015 XT/AT Style Keyboard $ 59.95 Point Wiring 41256-120 512K RAM (18 Chips) $ 71.10 JE1012 Baby AT Flip -Top Case $ 69.95 31/62 JE1032 200W Power supply $ 89.95 JE417 (Pictured) Connection JE1022 5,4" High Density Disk Drive $109.95 JE1003 Baby AT Motherboard JE411 (6'2. No Pads, Gen. Purp ) $12.95 (Zero -K RAM-incl. Award BIOS ROM) . $429.95 JE415 16',No Pads. PC/)(T) $14.95 Regular List $880.80 JE417 (6'2. Plated w/Pads. Pcncr). . $19.95 JE23 JE24 JE27 SAVE $80.85! Part Dim. Contact Binding Pace Extender Boards No La W Points Posts Designed for JE1008 IBM AT Compatible Kit $799.95 JE20 63/4 x 3/4 200 o $2.29 Troubleshooting Jameco's IBM PC/XT Compatible Kit JE21 33/4 x 23/4 400 0 $ 4.49 and Testing 4164-150 128K RAM (18 Chips) $22.50 JE22 6'7x13'4 630 0 $ 5.95 JE419 (Pictured) JE1040 Floppy Controller Card $34.95 JE23 6's x 2's 830 0 $ 7.49 JE1010 Flip -Top Case $34.95 JE24 63/4 x 1,360 2 $14.95 XT/AT Style Keyboard $59.95 JE419 (5'. Extender 22/44 Connector) $19.95 JE1015 JE25 6's x 4'. 1,660 3 $22.95 JE1030 150 Watt Power Supply $69.95 JE421 (V. Extender. 31/62 Connector) 6's x 53. 4 $19.95 JE1050 Mono/Graph. CM w/P.Port $59.95 JE26 2,390 $27.95 JE1020 osoo Disk Dore $89.95 JE27 7'. x 7', 3,220 4 $37.95 Commodore VIC-20 SAVE GREEN 12 Mono. Green Monitor $99.95 Motherboard $72.15 JE1000 XT Motherboard (Zero -K RAM-inct Extended 80 -Column Award BIOS ROM) $99 95 .013=11321 Card for Apple lle CV20 FREE! QUICKSOFT PC 80 Col. /64K RAM Doubles UMW. amount of data your Apple lie WRITE WORD PROCESSING can display as well as its mem SOFTWARE INCLUDED! ory capacity Ideal for word processing Complete with --rv Regular List 5572.10 instructions JE1004 (IBM- PC/XT Compatible Kit) $499.95 JE864 $49.95 May have to troubleshoot or just use for spare parts. Jameco's 4.77/8MHz Turbo IBM Compatible Kit ADD12 CV20 Includes: (1) 6560, (2) 6522. (1) 6502 (2) Same as JE1004 except comes with 640K RAM, JE1001 (Turbo) 4 77/8MHz $99.95 6116P-4, and much more! motherboard, JE1071 multi I/O with controller and graphics, and AMBER monitor. Additional Apple Compatible CV20 (VIC-20 Motherboard) $ 9.95 SAVE $95.70 Regular List $695.65 Products Available 089033 (ura VIC-20 Schematics) $19.95 JE1005 (IBM PC/XT Turbo Compatible Kit) . $599.95 Additional Accessories NEW! Seagate 20, for Commodore IBM Compatible Motherboards 30 & 40MB VIC-20, C-64 & C-128 4.77/8MHz operation (Turbo only) Height 8087 Math Co -processor capability Hard Disk JE232CM (Pictured) BIOS ROM included Drives *CM 1 (300B Modem VIC-20. C-64) . $19.95 JE1001 4.77/8MHz .. 6129.95 $119.95 ST225K (Pictured) *JE232CM (RS232 Inter. vic-20, c-64). $39.95 JE1000 4.77MHz .... $0995 $ 99.95 ST225 20ue Drive only (PC/1(1741) $269.95 CPS10 (C-64 Power Supply) $39.95 ST225K nue w/Controllef (PC/XT) $329.95 CPS128 )c-126 .. $59.95 Additional Add-Ons Available! 30MB w/Cont (PC/XT/AT) .. $369.95 Al,compatible with C-128 in 64 mode ,'1r ST238K Color Graphics Card EGA Card for PC/XT/AT ST251XT 406111w/C.ont Card (PC/XT) . $549.95 ZUCKIER1304111) for PC/XT/AT ST251AT awe v./cone Card ... $589.95 TANDY 1000 11-1Pmho per Expansion Memory 4 Jameco PC/XT Half Card & AT Compatible Expand the memory of your Disk Drives Tandy 1000 1128K Version) to as much as 640K Also includes 1-41,1111111. JE1022 (Pictured) DMA controller chip TE512 Includes 512K RAM $119.95 JE1020 (360K Dose. PC/XT/AT) ... $ 89.95 TANG Plug-in Clock option chip (only) .... $39.95 JE1022 (1 2MB. AT Compatible) . $109.95 Text 40 or 80 x 25 Graphics 320 or 640 Graphics 720 x 348 16 out of 64 colors 20Meg Hard Disk 200 Parallel Profiler Port Manual included Manual included DATA BOOKS T2OMB 20MB Hard Disk Drive Board JE1052 $49.95 JE1055 $179.95 30003 National Linear Data Book (82) $19.95 for Tandy 1000 $494.95 I/O Cards for Multi I/O w/Controller 30005 Logic Data Book . VolII (84) SX2OMB 20MB Hard Disk Drive Board 30909 Intense Data Book (87) $14.95 for Tandy 1000SX $499.95 PC/XT/AT & Graphics for PC/XT 21398 CMOS Cookbook(86)$19.95 1000 210830 Intel Memory Handbook (87) Print. Port 230843 Intel Microsystern Hndbk. Set (87). $211447.:999555 IMO rl RS232 Port Board with Game Port MUFFIN/SPRITE-STYLE FANS Clock Calendar Manual included

Expand the memory on your Tandy 10001128K Ver., i,r. JE1060 (Pletnred) TA4505 $11.95 - Printer pod RS232 port Floppy controller much as 640K Complete with an RS232 port. clo, ir1,1.ir. Tony Industries 14 6b sq . 50 .1,0 RAM Disk. Pont,, S000ier and on -board DMA cent, di Graphics Manual included JE1060 vo for XT. . . $59.95 SU2A1 $11.95 MT512 Includes 512K RAM $199.95 JE1065 I/O for AT. $59.95 JE1071 $129.95 EG&G Rolron 13 125 square 34 clrn 1 $20 Minimum Order - U.S. Funds Only California Residents: Add 6%, 61/2% or 7% Sales Tax Data Sheets - 504 each Shipping: Add 5°/o plus $1.50 Insurance IBM is a registered trademark of International Business Machines Prices Subject to Change

Mail Omer Esuctierscswooldwles Send $1.00 Postage for a Send $1.00 Postage for a FREE 1988 CATALOG FREE Seasonal Flyer MasterCard ameco VISA - Telex: 176043 FAX 415-592-2503 ELECTRONICS c 1987 Jameco Electronics 11/87 1355 SHOREWAY RD., BELMONT, CA 94002 FOR ORDERS ONLY 415-592-8097 ALL OTHER INQUIRIES 415-592-8121

CIRCLE 114 ON FREE INFORMATION CARD What's New at AMERICAN DESIGN COMPONENTS? We warehouse 60,000 items at51/4", 51/4" 53/4" HIGH -RESOLUTION V V American Design Components-10Mb 1/2 HT. FULL TTL MONITORS expensive, often hard -to -find com- HT. ponents for sale at a fraction of theirHARD DISK original cost! DISK DRIVES DISK DRIVES You'll find every part you need - DRIVE 48/96 TPI either brand new, or removed from 1.2 Mb. 48 TPI equipment (RFE) in excellent condi- (AT (IBM' tion. But quantities are limited. Order Compat.) Corn pat.) from this ad, or visit our retail show- (IBM'omcat. DS.single-double density; 80 track. Double sided double density, full Mfr room and find exactly what you ) Panasonic #JU 475 height drive. 48 T.P.I., 80 tracks. Mir Tandon TM100-2 12VDC Mtd. in metal housing. need from the thousands of items onFits standard 5% " spacing. Shock!tern 410005 $119.00 New Schematic supplied display. mtd. High speed, low power. 96 TPI, DS/Quad Density Item #7928 $79.00 Mfr Seagate, Tandon IDOS 3.2 Compatible) 12", Green Phosphor OPEN MON. Sat., 9 5 2f or $150.00 Item #13250 $ 159.00 NewTandon TM55 4. DS Quad 96 TPI, DS/Quad Density Item 46811 $19.95 New Controller Card for above Item #1904 $79.00 Mir CDC #9409T 9", Amber THERE'S NO RISK. Item #10150 $89.00 2 for $150.00 Item #1893$ 99.00 Item a14332 $14.95 New With our full 90 -day warranty, any purchase can be returned for MAGNIFYING /./ IBM® ADC KITS.. . SWITCHING POWER any reason for full credit or refund.LAMP PC/XT IC Socket Kit SUPPLY KEYBOARD 100 Ass't. Sockets! Consisting ADAM COMPUTER of 100 assorted IC sockets. Mt, From 14 to 40 Pin. PITRIS111111 Item #5309 $9.95 New Components & Parts Kit Hundreds of components! Con- sisting of Heat Sinks, Capacitor, 19 115 & 230V, 47 440 Hz. Multi position, 30", IMMO Trimpots, Resistors, and MORE, 1111111 111111 completely adjustable Input: 90 -135V/180 -270V 1 Item #7230 $15.00 New Output: 5VDC @ 5.5A as - swing arm w/3 -way metal C -clamp. Switch Kit Has 4" diopter magnifying lens, + 12VDC @ .4A Illuminated cap and number 35 Ass't. Switches! Consisting -12VDC @ .3A w/ruler. Porcelain lamp socket, & lock indicators. of 35 assorted: Dip. Toggle, Perforated metal case enclosure. iii(Less on/off switch; uses up to a 60W Slide, and Sensitive Miniature Dim.: 91/2"1 x 3.4"W x 2"H. Low profile design. printer) bulb. Color: Beige. UL listed. and Standard Size Switches. Mfr General Instrument No wiring nec. (just plugs together). HookupItem #13136 $24.95 New diagram included. Includes: Keyboard, 1 cas !tern #11041 $49.95 New Item #5307 $9.95 New Item #7983 $14.95 New sette digital data drive, 2 game controllers,American's COMPUTER GRADE power supply, and one cassette. Capable of POWER SUPPLY running CP/M, has built-in word processor.IBM PC/XT- Item #7410Complete $99.00 ADAM COMPATIBLE 111111111t 51/4" COMPUTER. . DISK Contains: DRIVE 256K RAM; XT/AT Style Keyboard; Other uses -runs CB & ear radios. Gives your Adam fast, Comes ready to plug in! reliable data storage Nommuir 51/4" Full -Height Floppy DC Output: - 5V @ .5 amp. & retrieval. Can hold up Disk Drive + 5V @ 3 amp. to 160K bytes of information. Uses + 12V @6 amp. industry -standard SS/DD disks. Connects 10Mb Full -Height Hard Disk Drive Input 115V/60Hz. Dim.: 9%"W directly to your Adam memory console. x 3." H (Rubber ft. incl Comes w/disk drive power supply, Disk Hard Disk & Floppy Disk Manager disk and owners manual. Item #9501 $24.95 New Mfr- Coleco, model 7817 Controller Cards Item #14331 Item #12830 Like Now - $199.00 Color/Monochrome Monitor Card - BATTERIES - ADAM PRINTER (monitor not included). $549.95 New FANS - BLOWERS COLECOVISION Insides of the COMMODORE GELL CELL/LEAD ACID GAME COMMODORE CARTRIDGES BATTERIES . . . (Factory returns - COMPUTER tested good!) C-64 RECHARGEABLE - Used for solar Consists of 12 asstd. cartridges. energy storage, alarm systems, Includes: Number Nabber, Star remote control boats, robots, etc. Post, Financial Advisor, Radar Rat, Jupiter Land, Magic Cam- pos, Viduzzles, Golf, Easy Cele, Simon Basic, Dragon's Den, & Complete, less top cover plate. Friction ABC Voice. Item #13573 feed. Takes standard paper 81/2 " x 11" (Customer returns; tested - operational.) Set of 12 - $49.95 New Item #8839 $69.50 C16 & + 4 Consists of 9 asstd. cartridges. ADAM Accessories.. . Also includes Inc udes Script + 2, Celt Plus, power supply, Script +, Jack Attack, Pirate Ad- Data Drive - instructionCommodore VIC 20 CPU board & ventures, Atomic Miss, Strange Item #6641 $19.95 manual, modulator.mechanical keyboard. GuaranteedOdyssey, Financial Advisor, & Printer Power Supply - and one Donkey Kong cartridge.not to work. (For parts only.) Logo. Item #13572 6V @ 7.5AH Item #7411 Item #12144 $14.95 RFE Dim 5'."L x 3'."H x 2"D item 46642 $14.95 $29.95 Set of 12 - $29.95 New Mfr EPC #0031 ASCII Keyboard - COLECOVISION to COLECOVISION COMMODORE/AMIGA Item 413324 $5.95 Item #6643 $19.95 ADAM Expansion Kit Accessories . . . POWER SUPPLY Controllers - 6V @ 2.6AH Dim 5%"L x 2%"H x 1%"D (Set of 4) item #7013 $9.95 EXPANSION MODULE #2 Mfr - EPC #0030 Adam Cassettes - ifor,W.4.1010.1/1141101..... Play arcade quality driving & rac Item #13326 $3.95 (Consisting of Smart Basic, Buck Rogers & ling games on your ColecoVision. blank cassette I Item #7786 Incl. Turbo cartridge. 12V @ 4.5AH BAKER'S DOZEN - $19.95 Item #13146 $39.95 New Dim.: 6"L a 3.4"H x 2',:"D Adam Link Modem - Mfr - EPC #0027 ROLLER CONTROLLER Item #13325 $7.95 (Software included.) Gives full 360° game control. Hi - Item 412358 $29.95 speed action of an arcade. Can be DC Output: 12V @ 2.6AH Auto -Dialer used w 'the Adam Incl. Slither cart. + 5V @ 8 amps. This expansion module lust plugs + 12V @ 1 amp. Dim.: 5%"L x x 2`,."D Address Book - into your ColecoVision. With printerItem #13147 $39.95 New - 5V @ 250 ma. Mfr EPC #0026 Item 412365 $19.95power supply and data drive (both Input: 110VAC/60 Hz., ± 20% Item #13323 $5.95 included). you will have a working SUPER ACTION Adam Daisy Print Wheel - Dim.: 12"L x 33/4"H x 5%"D 12V 0 1.2AH Item #13305 $3.95Adam Computer. Adam keyboard, CONTROLLER SET Encl. in alum. housing. Fan cooled. one Smart basic cassette and hook-Gives you indiv. control of 4 + on- Mfr - Shindenger Electric Dim3'."L x 2"H x 1."0 Adam Ribbon Cartridge - up diagram also included. screen players. Inc! Baseball cart. #130569SXD Mfr -EPC #0025 Item #13306 $3.95 Item #9918 $59.50Item #13148 $39.95 NewItem #14707 $19.95 New Item #13327 $3.95 150 CIRCLE 198 ON FREE INFORMATION CARD "The First Source"- for electromechanical & electronic equipment and components- AMERICAN DESIGN COMPONENTS!

PC 8300 HOME COMPUTER115 CFM 27 CFM INTEGRATED CIRCUITS . . (Advanced version of the Timex 1000) MUFFIN ° MINI TYPE FANS Linear. . . DS8T28N $1.57 75115 $1.07 FANS LH0002CN $5.35 LM1456V 1.75 75123N 1.34 LM I OCLH 2.65 LM1458N .44 75124N 1.34 LH0070-014 3.55 LM 1 488N .62 75138N 2.85 TL071CP .53 LM 1496N .90 75154N 1.25 INN 115VAC, 50 60Hz.; 12W. Low TL072CP .71 LM1899N 1.43 75450N .53 noise level fans, can be mtd. for LM301N .32 ULN2003A 75451CN blowing or exhaust. .90 .44 LM307N DS26LS31CN1 34 75452CN .44 715VAC/60Hz.; 21W.; 28A.; 11/2" STANDARD LM310N 1.16DS26LS32CN 1.34 75453CN .44 42 -key mechanical keyboard3100 RPM; 5 -blade model; alu- 7 metal blades LM311N .4)LM2901N .53 75463N .53 (not membrane). Contains 2K RAM. Reverseminum housing. Can be mtd. for Dim.: 3%" sq. x 11/2" deep LM317K 2.65LM2903N .53 75472 .80 video, Z804, 6.5MHz processor, ROM 8K blowing or exhaust. NEW - Rotron #SU2A1 LM317L2 .62LM2907N 1.75 75492N .71 BASIC. Graphics capability/sound-music, NEW Item #1604 $12.95 Item #5970 $7.95 LM317MP .80LM2917N 1.39 76477 3.55 TV or monitor. Joystick input operates on LM317T .90LM2917-14N1.34 115 VAC. Includes: AC adapter. TV cable. USED Howard Ind. 31 5 3455USED - Rotron LM318N 1.07LM2931CT 1.07 Z8000 Series.. . & pair of cassette cables. Will run all prere Item #5345 $ 5.95 Item #1873 $5.95 LM319N 1.07 corded tapes for Sinclair/Timex 10002X85 MC3346P .90 Z80 $1.57 LM324N .35 Mfr - Power 3000. (In orig. boxes.) 150 CFM SUPER 12 VDC MC3486 1.34 Z80-CTC LM3342 1.07 1.61 MC3487 1.34 Z80 -DART 4.45 Item #10336 $29.95 NewVENTURI MINI LM336Z .98 SG3524 1.75 280 -DMA 4.45 . . FAN BOXER" LM337MP 1.03 Accessories . LM3900N .53 280-PIO 1.61 LM337T 1.34 * 16K RAMPACK upgrade FANS LM3914N 1.75 280-510/1 LM338K 4.45 3.55 RC4136N 80 280A 1.66 Item #10337 $9.95 New LM339N .44 RC4151NB .90 2804 -DART 4.72 LF347N .90 * 32K RAMPACK upgrade RC4193NBIDE) 2.65 2804 -DMA 5.35 LM348N .62 Item 412148 $19.95 New 7805K 1.21 280A -P10 1.75 LM350K 3.55 7812K 1.21 280B 3.55 LF353N .53 MICROCOMPUTERS 7815K 1.21 280B-CTC 4.45 LF356N .807818K 1.21 with EPROM Ball bearing; 115 VAC, 60 Hz.; 21308-P10 4.45 MC68701 - .195/.178 amps. Has 2 sets of LM358N .44 7824K 1.21 mtg. holes (fits standard rack or LM380N .80 78057 .44 EPROMS. . . larger). Can be mtd. for blowing or40 CFM, ball bearing, 3 amps. LM380N-8 .98 7812T 44 Dim.: 1" thin x 31." square LM381N 1.16 78157 .44 TMS2532 $3.55 exhaust. Dim.: 5" sq. x 11/2" deep. TMS2564 Mfr Mfr - IMC #3610 LB012 LM383T 1.34 7818T .44 8.05 Rotron 2708 3.55 Item #1866 $19.95 New Item #13598$ 1 2.95LM3852 1.70 78247 .44 LM386N.4 .80 78S40 1.75 TMS2716 5.99 NMI 2716 2.24 JOYSTICK EMI An 8 -bit single chip microcomputer unit, en- LM389N .90 7905K 1.21 CONTROLLERS Ate,, LM393N .41 7906K 1.21 27C16 8.95 hances the capabilities of the M6800 family. FILTER 2732 2.50 TTL compat. Req. one + 5V power supply LF398N 2.15 7912K 1.21 for nonprog. operation. Incl. 2K eprom, 128 6 Amp., LF411CN .71 7915K 1.21 2732A-25 2.95 bytes RAM, serial comm. interface par- 120/ TL494CN 1.75 7918K 1.21 27C32 9.85 2764-25 allel I/O & 3 -function programmable timer. 240 Volt TL496CP 1.34 7924K 1.21 2.95 Item #9496 (house numbered) $9.95 TL497ACN 1.9779057 53 2764A-25 2.95 NE555V .2679127 .53 27C64 6.25 MC68705 - XR-L555 .6279157 .53 27128-25 2.65 LM556N .53 791137 .53 27128A-25 4.45 Provides the most effective NE558N 1.0779241 .53 W attenuation of 'line -to -ground' 27C256-2512.55 NE564N 1.7579L124C .53 e and 'line -to -line' noise across the 68701 9.95 . LM565N .90 79L154C .53 frequency range. LM5B6CN 1.25LF13201N 2.33 88705 9.95 HMOS, 8 -bit med. perform. microcomputer.Fits Atari, Apple, Commodore, Dim.: 2.62" x 1.98' x .81'. LM567V .80 LM13600N 1 07 6800 Series. . . On -chip resources: 3776 bytes eprom, 112and our #10336 PC8300 Com Mfr - SAE (equiv. to Corcom, NE570N 2.24 LM 1889 1.85 bytes RAM. 8 inputs & 24 programmable bi- puter. Has 4 -ft. cord with plug. type 6ECI) NE571N 1.7575107N .90 6800 $2.12 directional outputs. Self -programming boot Dim.: 3 1/2 " sq. x1 'h" H Item #10959 $4.95 strap. NE592N .80 75108N .90 6821 2.72 Item #13608 $9.95 Item #12143 $5.95 New 2 for $9.00LM748CN .53 75110A 1.34 684096P 5.95 COMPUTER & GAME STEPPING MOTORS Fig. 2 - MOTORS - TIMERS - PUMPS - - EQUIPMENT - for ROBOTICS . . . Shaft l'is" LPOWER SUPPLIES - VOLTAGE REGULATORS -50" deep x 3/." dia. 15" COMPOSITE ME HANI AL NEON TRANSFORMER Fig. 1t .spix VIDEO MONITOR KEYBOARDS . . . (Hi -Voltage) Precision ai steppers with increments from 1 to 7.5 degrees. -.'--,.' 1009 Speeds up to - roe 5,000 steps. Shaft 9' ,0' L app 65 JCad x 's" dia. e<1' Stall 7300 VAC ItemStep Volts Torque @ 5 Ma. No. Angle DCoz/in Type Mfr. & Pert No. Fig Price 48 -KEY - Timex Z81/1000 May be used for powering neon lights, replacing oil burner ignition 5431 1 5 17 PM N.A. Phillips 1 $9.95 ea. Item #6712$ 5.95 New 15", green phosphor, high resolution 112 transformer, building Jacob's lad- A82310 -M2 75 -KEY - Timex or Adam der (spark gap). A high -volt. outlines center) and bandwidth from 10Hz to 2/$14.95 5275 1.8 1.8 72 PM Superior Electric 2 $19.95 ea For computer upgrade. put: '4 quick connect terminal & 30Hz ± 3dB. Operating volt.: case ground input fully enclosed 120/240VAC, 50/60Hz., 65VA max. 2 0 M061 -FF-6201B 2/$37.50 Item #7429 $5.95 Newmetal case. Weight: 12 lbs. Mfr - Motorola- Alpha Series 7630 1.83.0 200 PM Superior Electric 2 $34.50 ea. 66 -KEY - Commodore C-16Base mount: 41/2"H x 5`,,"W Item #10044 $34.95 New M092 FT 402 2 $59.50 Item #9394 $5.95 New Item #151 $9.95 RFE 140 VA AMERICAN DESIGN COMPONENTS, 62 JOSEPH STREET, MOONACHIE, N.J. 07074 MINIMUM MINI YES! Please send me the following items: 0 My checleor money order is enclosed. ORDER MICRO- Item How 0 Charge my credit card. $15. COMPUTER No. Many? Description Price Total 0 Visa 0 Master CardCI Amex RE 1 1 7 REGULATOR Card No. Exp. Date

Provides voltage regulation and ultra - Signature isolation for microprocessor -based equip- Telephone: Area Code Number ment. Contains less than 3% harmonic distortion, better than 60 dB traverse Total Name Shipping & handling, we ship UPS unless noise rejection. Contains dual outlet for otherwise specified. Add $3 plus 10% tote. Address CPU & monitor, and 6 ft. line cord. Canadian: $3 plus P.O. cost. Charge only. Input: 95 - 130V, 60Hz. City Output:120V @ 1.17A Sales Tax (N.J. residents only, Dimen.: 11%"L x 4%"H x 5%"W please add 6% of total) State Zip Mtd on metal base with rubber ft. ORDER TOTAL All inquiries end free catalog requests cell 201-939-2710. Mfr - Sole #63-13.114 Item #9999$ 99.00 New For all phone orders, call TOLL -FREE 800-524-0809. In New Jersey, 201-939-2710. CIRCLE 198 ON FREE INFORMATION CARD 151 ADVERTISING INDEX RADIO -ELECTRONICS does not assume any responsibility for errors that may appear in the index below. Free Information Number Page 81. 214 A.I.S. Satellite 20, 29 82 Digi-Key 140 61 Microprocessors Unitd. 106

108 AMC Sales 128 -Digital Research Computers 194 NRI 16-19, 90

76 AP Products 14 -Electronics Book Club 21 202 NuScope Associates 106

107 All Electronics 147 199 Electronic Salvage Parts 136 206, 217 OCTE Electronics 28. 29 127 103 Allen W.B. 25 120, 188 Elephant Electronics 28. 29 110 Omnitron - Amazing Devices I 98 100 Firestik II 128 Pacific Cable 133 198 American Design Components... 105-106 -Fordham Radio CV4 101 Pomona 80 114 84 Appliance Service 28 121, 192 Fluke Mfg 22. 38 203 Parts Express

77 B&K Precision 21 210 Garrett Industries 29 Prentice -Hall 118-121 119 181 Banner Books 40 -Grantham College of Engineering 12 78 Radio Shack

98 Beckman Industrial 125 219 Huntron 191 SEL Labs. 110

195 Bidan Associates 28 65 J& W 56 177, 178 Sencore 9 II 13, 15 85 Blue Star Industries 28 JDR Instruments 179, 180 Sencore 136 109 C & S Sales 10 113, 182 JDR Microdev ices 142-143 186 Silicon Valley Surplus

60 CIE 14-37 183, 184 JDR Microdo ices 144-145 204 T S M CV3

212 Cabletronics 28 185 ,IDR Microdev ices 146 92, 193Tektronix CV2. 42 112 189 Caig 126 114 Jameco 148-149 220 Time Line vn 216 Circuit Cellar 29 115 Jensen Tools 29 215 Time Motion - Command Productions 42 Joseph's 27 211 Trans -Am 129 10 79 Communications Electronics 7 194 K & S 20 207 United Electronic Supply 20 197 Cook's Institute 129 208 Life Products 28 218 United Imports 20 200 Consumertronics 106 87 MCM Electronics 141 Universal Short Wave Radio 29 205 Crystek .. 26 93 Mark V. Electronics I 19 213 VIP 29 196 Daetron .. 152 McGraw Hill Book Club 5 209 Valve Corp. 130 190 Datek 89 McGraw Hill Book Club 53-55 187 WPT Publications 24 127 Deco Industries 28. 29 63 Micro -Mart .. 138 176 Wahl ('tipper Gernsback Publications, Inc. 500-B Bi-County Blvd. IDOES YOUR DIGITAL CAPACITANCE METER DoTHisi Farmingdale, NY 11735 (516) 293.3000 FULL 4 DIGIT 0.5 INCH LCD DISPLAY COMPLETELY AUTORANGING WITH 10 RANGE MANUAL CAPABILITY President: Larry Steckler AND THIS AND THIS Vice President: Cathy Steckler RANGE OF 0.0 pF to 1 FARAD 1999 9 mF) IDENTIFIES TRANSISTORS (NPN, PNP) ForAdvertising ONLY 0.5% BASIC ACCURACYUP TO 100uF AND THEIR LEADS (E, B, C, ETC.) 516-293.3000 AND THIS AND THIS Larry Steckler READS DIELECTRIC ABSORPTION TESTS ZENER DIODES AND RECTIFIERS. publisher UP TO 20V ZENER WITH AC ADAPTOR, AND THIS ZENER VOLTAGE WITH 9V BATTERY Arline Fishman EXTENDED PSEUDO 5 DIGIT DEPENDS ONITSCONDITION advertising director RESOLUTION ON SOME RANGES ONLY AND THIS Shelli Weinman AND THIS AUTOMATICALLY CALCULATES LENGTHS advertising associate ABILITY TO ZERO LARGE CAPACITANCE OF CABLES IN FEET, METRES, MILES, VALUES UP TO 9999 uF Lisa Strassman KILOMETRES (THEORETICAL RANGE credit manager AND THIS OF 9,999 MILES) CALCULATES TRUE CAPACITANCE Christina Estrada IF CAPACITOR IS LEAKY AND THIS advertising assistant ABILITY TO SORT CAPACITORS IN AND THIS MANY DIFFERENT MODES SALES OFFICES DIODE CLAMP AND FUSED AND THIS PROTECTED INPUT. ABILITY TO READ LEAKY CAPACITANCE EAST/SOUTHEAST DISCHARGE RESISTOR IN OFF (INSULATION RESISTANCE OR CURRENT) Stanley Levitan POSITION AT TERMINAL INPUTS. POWERED BY 9V BATTERY AND THIS Eastern Sales Manager ONE YEAR PARTS & CALCULATES TIME CONSTANTS WITH Radio -Electronics LAMOUR WARRANTY USER DEFINED RESISTANCE VALUES 259-23 57th Avenue AND THIS Little Neck, NY 11362 FOR ONLY THIS HOLD FUNCTION FREEZES DISPLAY 718-428-6037, 516-293-3000 SHIPPING INSTRUCTIONS: All units shipped out F.O.B. Buffalo NY via United Parcel Service (except Hawaii & Alaska) MIDWEST/Texas/Arkansas/ unless otherwise indicated (in which case shipments will be F.O.B. Canada) Okla. Ralph Bergen PLEASE SEND ME U.S. FUNDS Midwest Sales Manager (QUANTITY) MC300(S) a. $169.95 $ Radio -Electronics CARRYING CASE S 16.95 540 Frontage Road-Suite 339 AC ADAPTOR S 9.95 Northfield, IL 60093 MODEL SHIPPING AND HANDLING (u $5.00 PER INSTRUMENT 312-446-1444 Appro. Su [ [CHECK [ MONEY ORDER S TOTAL S MC300 1 VISA 1 I MASTERCARD PACIFIC COAST/ Mountain [ I CARD NO. States DAETRON EXPIRY DATE SIGNATURE Marvin Green a clivisorf of Bergeron TechnOlogtes Inc. NAME Pacific Sales Manager 7686 KIMBEL STREET, UNIT 5 ADDRESS Radio -Electronics MISSISSAUGA. ONT.. CANADA CITY STATE ZIP CODE 5430 Van Nuys Blvd. Suite 316 L5S 1E9 (416)676-1600 Van Nuys, CA 91401 DEALER ENQUIRIES INVITED 1-818-986-2001 CIRCLE 196 ON FREE INFORMATION CARD 152 ELECTRONICS KITS TSM IN AMERICA NC. 2065 BOSTON POST ROAD LARCHMONT N Y.10538

71.

-...r __ AIL ...,... ---,...- .,- -_-_ 1;.= 2065 BOSTON , LARCHMONT N Y 10538 -`,.E:.t..1.- TEL 914-937-2447 OR 914 514 V:N- ;81 ...varsocceemeorrox ,,,,,,,eraaaa... -.-

...... SM 201 s 26 .77 $ 1 7 . 50 TSM 212 LOW OPERATING VOLTAGE. DIGITAL CLOCK. 5,16' READ OUT, POWER P.C.B. SYMBOLS SPOT TOM 220 AND TOM 221 COMPATIBL SUPPLY 12V D C/0 2A WITH HOUR AND CONTRCLED BY A MICROPHONE 0= 00 191rorn MINUTE SETTING CCNTRCLS / POWER SUPPLY 12Vr IA OUTPUT 0.5A. Translert shed' S2 00 each MODULATOR SAFE 3 CHAANEL LIGHT ....,C,1 .... r. TSM 157 340.00 0_7_ OD 254mm DIGITAL CLOCK AND UP TO 24 MN TSM 9 1 14.00 Transfer' sheet $200 each (TSM 5A $26.30 1/100 S CHRONOMETER. COUNT DOWN 1.Lool_1:01.21.1:: AUDIO POWER MODULE 70/N PEAK POWER AUDIO PREAMPLIFIER FOR GUITAR, NP CAPABILITY FOR THE CLOCK SENSITIVY 47K/5mV, OUTPUT LEVEL 35W RMS, INPUT SENSITIW 47%/800mV 4.. POSER SUPPLY 12V D.C.OR AC 11)-- 00 3I7mm OUTPUT 40/811 POWER SUPPLY 39V D C 47K/1 5V, VOLUME CONTROL VARIABLE POWER SUPPLY 25V DC / 0 IA I TSM 177 233.20 L2 5A tt Transtert sheet $2.00 each DIGITAL VOLTMETERS 0 V TO 999 V 0 C .L. POWER SUPPLY 12V D C /0 5A r TSM 34 s 9. 1 9 4 STEREO RIM PREAMPLIFIER NPUT r TSM 206 $ 10.1 6 CE OD 397min SENSITIVY 47K/3nW, OUTPUT 700mV, METRONOME; POWER SUPPLY 9 - 12V D.C. Transfer? sheet S2 00 each POWER SUPPLY 12V DC/ 0 IA 4 $29.50 TSM 210 210.50 TSM 214 8 C HANNEL CATE RPLAR SAFE LOW >.TSM35 $ 1 . 1 9 FULLY RANOOMSED ELECTRCNC DICE, CECO 500rnm VOLTAGE OPERATION USING TSM 220 MiCIIK/PHONE STEREO PREAMPLIFIER, POWER SUPPLY 9 . 12V D C /0.1A AND 221 SPOT 9V 0 C/ 0 5 A Transfen shA et S2 00 each INPUT SENSITIW 5mW20011 OR MORE, 4 OUTPUT 700mV, POWER SUPPLY 12V D.C. TSM 54 $ 1 3.85 - '01 A RA TRANSMITTER. POWER SUPPLY 9V ...... 00 140mm D.C. / 0.5A 040mn TSM 122 $ 1 3 .11 6 TSM 67 239.74 TSM 150 4 A 254orn STEREO AMPLIFIER 2YAOW PEAK POWER ALL -BAND FM/VHRUHF ANTENNA. 20dB $82.50 Transfer' sheet S2 00 eacn HOME PROGRAMER. 4 DEVICES CONTROL. . SENSITIVY INPUT 47111300mV, OUTPUT AMPLIFIER-. POWER SUPPLY 8/12V D.C) 0 15A 20 PROGRAMS. OPERATOR WITH RELAYS . 25'847 VOLUME, BALANCE, BASS, POWER SUPPLY 12V D.C./0.1A. 0 OD 254n1rr TREBLE. CONTROLS. POWER SUPPLY TSM 31 $14.77 0 0 I 105mr 12V D.C.314 A. RA STEREO DECODER, POWER SUPPLY > ISM 130 $26.77 A 508mn u. Transfer' sheet 32 00 each TSM 44 $ 11 .18 12V D.C. / 0.1A 24 TUNE DOOR CHIME, OUTPUT 3/4 WATTS POWER SUPPLY 12V D.CJ1A. o A01 - AUDIO POWER MODULE, 50W PEN( POWER TSM 62 $13.00 , OD 960mm' 25W RMS, INPUT SENSITIVY ISOMW/471( CAR ANTEMM PREAMPLIFIER lAWA.WIFIA. $ 4 6 .1 5 TSM 123 I 094rnryl OUTPUT IMPEDANCE 4/141 POWER SUPPLY OWFR SUPPLYA 2/16V D C/0 Ill SONDCONDRIONEROUTPUT LEVEL 600mV 0A 40V D.CJ2A 1 IMInun TSM 335 $16.66 TO BE CONNECTED TO AMPLIFIER AUXL IA- TSM 220 $25.30 Transfer! sheet $2.00 each RY NPUT. POKER SUPPLY 17V D.C. 'TSM 11 $15.50 PHYSIOLOGC TONE CONTROL, STEREO AUDIO AMPLIRER 30W PEAK POWER, 15W 4 1..1_ A 1270 mm INPUT IMPEDANCE 150mV/160K, OUTPUT ' TSM 78 UNNEFISAL ALARM FOR 64 LEDS SPOT FOR SAFE LIGHT MODUL- WAS, INPUT SENSITIVY 47111150mV, 2.5 e 160mre Eva 8000eW. POWER SUPPLY 25V D.C. HOME AND CAR, DELAYED EXIT TIME, AD. ATOR SUPPLIED WITH BOO TO 8 n OUTPUT. COMPLETE WITH VOILA/E. ASTABLE SOUND ALARM TAMPER PROOF. Transferl sheet S2 003ra"cr BASS, TREBLE CONTROL; POWER SUPPLY OPERATION WITH CONTACT SWITCHES ,1 2/1 6V D.C./2A A 1270mm 1$ POWER SUPPLY 12V D C10,1 SA $33.23' 3 1 6 . 20 MEM TSM 5B 333.70 TSM 211 B 160rere AUDIO POWER MODULE 90W PEAK POWER TSM 121 21 7 .54 SAFE LOW VOLTAGE 2.WAY CATE RPLAR C 396fern 45W RMS, INPUT SENSITIVY 47K/800rnV RANDOMLY FLASHING AND WNKNO. TOM Transfer) sheet S2 00 earn 16 LED DISPLAY THERA/CRETE Fl . POWER OUTPUT 4DISCI. POWER SUPPLY 39V D.C./3 SUPPLY IS/ISV D C./0 15A 220 AND TSM 221 SPOT COMPATIBLE POWER SUPPLY 12V/0.5A. 11 I 254mm s I 2.97 4 -1101111 TSM 18 IN 2 076mm AUDIO AMPLIFIER 15W PEAK POWER,7.5W , 3 16.1 5 $17.20 TSM 105 TSM 221 3-4 II gp 762thm RMS.INPUT SENSITIVY 471U150mV, 2.6 3 ELECTRONIC ALARM SIREN. AA IMPEDAN- 25 L EDS SPOT FOR SAFE LIGHT MOOL.L II TO ST OUTPUT. COMPLETE WITH VOLUME Transfer' sheet 52 a0 each CE. 10 WATTS RATING. POWER SUPPLY AWON SUPPLIED WITH BOY BASS, TREBLE CONTROL, POWER SUPPLY ../' DC , HON SPEAKER NOT INCLUDED. , 4,12/16V D.C. /ISA S12V 333.99 122.62 TSM 19 *52.05 TSM 146 TSM 85 --$1141$ I 254mm r THE DELAY SYSTEM FROM MEC TO 16 AUDIO 240W PEAK POWER, 120W RAS STEREO 2X5 BANDS EOUALIZER . SUPPLIED L/111 2 155mrn SENSITIVITY 47K/ 01 V.OUTPUT 4 T. WITH 10 POTENTIOMETERS, FREOUENCY MINUTES. POWER SUPPLY 12V D.C. II 3 762mm THD 03 %, RESPONSE 1 6 HZ -100 KHZ. RESPONSE 50142 TO 16 KHZ,POWER SUPPL 2 4 Transfer! sheet $200 each POWER SUPPLY 79V MAX. HEAT - X 12V D C /0.2A TSM 69 $15.93 SINKS NOT NCLUDED WITH THE KIT. ,s TELEPHONE AMPLIFIER WITH INDUCTIVE PICK. UP AND SPEAKER, ADJUSTABLE rTSM 66 216.60 $18 88 ..... o oo ° TSM147 `VOLUME, POWER SUPPLY 9/12V D C/0.1 0 AUDIO POWER MODULE 40W PEAK POWER 4 O 0 0 MONO 5 BANDS EQUALIZER SUPPLIED WITH 312.22 20W RAS. INPUT SENSITIW 47K/300mV S POTENTIOMETERS FREOUENCY RESPONSE rTSM 168 o ° 00 OUTPUT nien POWER SUPPLY 12V D.0 .2 50 HZ TO 15KHZ, POWER SUPPLY 2 X I2V NICGOUITOREPB-LER POWER SOURCE 3 ,,, $ ,W D.C./0.15A. 9V DC. TSM 68 222.66 4 STEREO AMPLIFIER 2 X 20W. % d TSM 86 236.50 O 0 9966 r TSM 2 142 $22.20 "N ..ssm INPUT 471300mV, OUTPUT 2,5/e0 SUP ELECTRONIC MONO REVERBERATICN SYS- Tr= shieteit°5112 00 each PLIED WITH HEATSNK AND BALANCE. REM, POWER SUPPLY IN DC VARIABLE SOLID STATE REGULATED PO VCLUAE, BASS, TREBLE, POWER SUPPLY r 4 WER SUPPLY 8V TO 380/2A V A TSM 88 238.77 . , TRANEOPMER IS NOT INCLUDED WITH THE 15$/1 RINCTrN GENERATOR FREOMNCY RANGE 246.30 1 . a. 1 PIT STEREO AMP. 2 X SOW 8142 TO 200KW.PROVIDNO SINUTRIANGLE 4) PEAK. NPUT SENSITIW 47K/300r1111 ,,119V, /SOUARE/SAW TOOTH WAWE FOWAS, PO- ...... OUTPUT van . SUPPLIEDWITH HEATSNK . WER SUPPLY 12V D.C./0.1A 4 AND BALANCE, VOLUME, BASS, TREBLE r TSM 58 $11.14 CONTROLS.POWER SUPPLY 40V D.C./2A TWO -STATION INTERCO./ WITH SPEAKER TSM 118 162.31 VOLUME CONTROL. POWER SOURCE SW 2V 320W PEAK POWER AMPLIFIER MOOLLE . L. D.C. / 0.4A 4 811 OUTPUT IMPEDANCE INPUT 47K/800mv 111.12 FREQUENCY RESPONSE 151I2 TO 60KNZ TSM 61 325.41 TSM 160 STEREO SFAULATC44, POWER SUPPLY 12V POWER SUPPLY 2 X 40V D.C/6A. FM RECEIVER. OUTPUT I WATT MIT . POWER SUPPLY 12/16V D C /02A D C./0.1A. ,REATSINKS NOT INCLUDED N THE KIT. 1 3 1 6.7 1 .1 RANSFFR TAPES $30.38 TSM 196 "TIN80 7 NPUT MIXER STEREO PREAMPLIFIER OR AUDIO BOOSTER STEREO 2 0 40W FOR rTSM 158 $ 2 74 2 14 NPUT MONO WITHOUT ATTENUATION. "rr CAR RADIO OUTPUT 2.141 POWER SUPPLY RA RECEIVER, OUTPUT 20 WATTS/BI INPUT 471(/100 TO 700mV.OUTPLIT 4714/ .4 116 V5 01 4..12/16V D.C./4A. POWER SUPPLY 12/16V D.C./2A rTSM < 100 TO 750mV. POWER SUPPLY 24V 0 C REGULATED POWER SUPPLY 5V DC rTSM 102 $22.50 /01 A POWER TRANSFORMERN:7f INCLUDED WITH 210.00 41 18 LED OUTPUT POWER LEVEL METER, 'TSM 211 THE NIT POWERED BY TIE MCOU-ATION MEDIUM WAVE RECEIVER 1 W,0.5 W FINE = 080mm AUDIO POWER. POWERSUPPLY Il... , ...) Tr anstert sheet $2.00 each TSM 128 s so.s 1 >9-12V DC./ 0 1 A TSM 116 V12 $11.50 335.40 100mm 2 %6 LED OUTPUT LEVEL -METE R. STEREO TSM 205 REGULATED POWER SUPPLY 12V DC Transfer! sheet S2 00 each POWER TRANISFORAER SNOT IsCLUDED 2 X 50W .POWER SUPPLY 15/20V D.C. RA RECEIVER, HEADPNCRIE STEREO OUTPUT = 127mm `POWER SUPPLY 9/12V 0 C tO IA WITH THE KIT. 0. Transfer! sheei S2 00 each $12.92 TSM 163 178rnrn KELVIN ELECTRONICS POWER SUPPLIES 5 , 7.5, 9, 12V/IA. Transferi sheet $200 each 7 FAIRCHILD AVE . PLAINVIEW. NY 11803 POWER TWAT:POWER NOT NOLUDED 516-3497620 FAX 516 34 9-7830 WITH THE KIT = 203mm Transfer! sheet $200 each AVAILABLE FROM TSM 99 $ 1 3 0.00 7SM 2 V4 225.85 NUTRON COMPUTER ELECTRONICS AUTO SOUND SYSTEM VEGAS KIT FESTIVE LIGHT DISPLAY (LED VARIABLE SOLID STATE REGULATED PO = 254mm 1269 EAST MAW STREET EL CAIGN POWER SUPPLY 12V 0 C / 2 5A WER SUPPLY 3V TO 14V/SATRANSFORMER Transfer' sheet S2 00 each 821 E ROOSEVELT ROD LOMBARD IL 60148 CA 92021 64 LED'S, AS MANY AS 800 .ROCI RAMS NOT INCLUDED IN THE KIT. TEL 312 691 89 00 TEL 619 442 70 22 ',.. SCOPE Audio LCD Sized 41/2DV 3,/2 Pocket SCOPE NtAimetel SCOPE BeerCapacitanc S9113ellevak° 9010\ Oak ,....6.

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CaPac\tance li conductance $2i995 6, "0"sae measurement lead set Test cluded battenes character $995& 9\1battery 4" hIgh od. per\ , lestleads dlstortxon 0 \ Low ConversonAutorna 46 step 32 lncludedAnal 7functon, cy )(1 01\11\seconds Transistor Soe-wave Polacl',`1 0434 lncluded irequen Kl -A7.1 negatNe leads lull scale selected to.5 trannegaessure ee Test wlth 20 Hz to ranges uF range 2 Kl-lz 8 2000 tole range to Crystal x100 trei valuesorcult range 150 lq-lz V_SI base Frequency to 81-Az 800 Hz Va13496C5 011 SCOPE sAhvo *WW1* 1..CD

Vigit Me 3,/2 x SCOPE FkIndons B witt Mode\ 0\0-632. pVVi -630 Mode\ $2995 0500 ounomcE\rc..ided 19 leads OlIRPFt1 lest 6`unctIons.zero accuracy Autzmtc °artery x ranges 1..014 21scE adost 53, x or\ kndical\ MeasurAcity Case c.11.1died Caryng testleads "Transs'or lpped Deluxea`c,curac/ :,ontrvotj 9460 050 0 Audi bte, 0 CC -30 tiF.1 '4(' gatrttest doode *.t -Ts credeolg ; AGPrnp'reasulernent Casa CarrYtro VPPeo $46113 CC -30 ASK FOR FREE CATALOG. Money orders, checks accepted. C.O.D.'s require 25% deposit.

Lrf Service b Shipping Charge Schedule Continental U.S.A. FOR ORDERS ADD $25-S100 54 50 $101-$250 $600 Toll Free $251-500 $600 $501-750 $1050 $751-1.000 $12.50 800-645-9518 $1D01-1500 $16 50 In NY State 800-832.1446 $1.501-2000 $20 00 260 Motoror Parkway, Hauppauge, amNY 11788 $2.001 andUP S25 00