Build This Sca/Fm Stereo Receiver

HIGH DEFINITION TV THE LATEST NEWS $2.25 AUGUST 1987 IN CANADA S2.75

TECHNOLOGY - VIDEO - STEREO - COMPUTERS - SERVICE

A 1 GERNSBACK BUILD THIS SCA/FM T PUBLICATION STEREO RECEIVER Listen to hidden signals on the FM band THE, ABC's of CET What it means to be a Certified Electronics Technician BUILD A UNIVERSAL TIMERR' For automated control of your

line -powered devices STEREO SCA/FM STEREO POWER TRANSISTOR RECEWER AMPLIFIERS TUNE r A design primer FM ROBOT SC0111 CONTROL ON TUNING LANGUAGE

Software that makes POWER VOLUME your robot go! PHONES

COMPUTERDIGEST IBM's new PS/2 08 PLUS:' Video News ©New Products i o 4 896 83 Satellite TV in Audio .Update NOW GET SCOPE, COUNTER AND DMM INPUT ALL AT ONCE THROUGH ONE PROBE!

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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 r T FlroMx A built-in, auto -ranging scope capability with ohmmeter provides counter/timer/DMM resistance measurements functions integrated into from 0.01 S2 to 2Gí1-as 1- nail cl its vertical, horizontal a, .- well as audible continuity. SI and trigger systems. For . Automatic diode/junction the same effort it takes to o : Í s detection and operator display a waveform you 4/1- 0 ü prompts serve to simplify can obtain digital readout b set-up and enhance of frequency, period, confidence in your width, totalized events, Imeasurements. delay time and .5 -time to The 2236: scope, accuracies of 0.001%. Tpk[ronrx 2230 or:.L..w 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 will your greater measurement confi- Digital Direct Ch 1 Voltage Meas. 0.5% DC; 2.0% direct -line answer dence and reduced circuit Readout AC RMS questions and expedite loading. Probe tip volts can Features Resistance: .01S/ to 200 MegS2 delivery. Orders include also be measured through Continuity/Temp: Audible/C° or F° probes, 30 -day free trial and 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 .1 -time with readout) 1-800-433-2323 for period, width and gated Accuracy video tape or literature, Trigger Modes P -P Auto, Norm, TV Field, TV Line, Single measurements are push- 1-800-426-2200 for button -simple. And the 2236 Sweep Weight 7.3 kg (16.21b) application assistance or offers an independent float- 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 Téktronbc COMMITTED TO EXCELLENCE

CIRCLE 92 ON FREE INFORMATION CARD August 1987 Éiéctronics. Vol. 58 No. 8 ILD THIS 39 SCA RECEIVER COM?UiERD%GÉS Hear the hidden signals on the FM band. IBM's NEW PS/Y Rudolf Graf and William Sheets cw..e srovAln. .y.« .p.w 45 VERSATILE DIGITAL TIMER Precisely controls any AC -powered device in your home. Ross Ortman

57 R -E ROBOT Part 9. Programming the robot. E. Steven Sarns DESIGN PC BOARDS ON YOUR PC it..,p..s'_ ..Mu It *my 75 PC SERVICE Direct -etch foil patterns for the digital timer. PAGE 61 TECHNOLOGY 48 HIGH DEFINITION TV The first major change in television since the addition of color is on its way! Josef Bernard

52 CERTIFICATION FOR ELECTRONICS TECHNICIANS The more you learn, the more you can earn. W. Clem Small, CET CIRCUITS AND COMPONENTS 55 TRANSISTOR AMPLIFIER DESIGN A basic design that solves many problems. PAGE 48 Jack Cunkleman DEPARTMENTS AND MORE 100 Advertising and Sales 6 VIDEO NEWS 28 SATELLITE TV Offices What's new in this fast - HDTV standards. 100 Advertising Index changing field. Bob Cooper, Jr. David Lachenbruch R -E 30 DESIGNER'S NOTEBOOK 8 Ask 16 EQUIPMENT REPORTS Logic family translation. 101 Free Information Card Regency Informant Scanning Robert Grossblatt 12 Receiver Letters 32 AUDIO UPDATE 82 Market Center 26 COMMUNICATIONS Expert answers. CORNER Larry Klein 21 New Lit Diversity reception and the wireless microphone. 24 New Products Herb Friedman 4 What's News N THE COVER Radio-

The FM band abounds with hidden Electronics® NIGH ounirtioN TY Hugo Gernsback (1884-1967) founder THE LATEST NEWS signals. Called SCA broadcasts or M. Harvey Gernsback, transmissions, some carry back- editor -in -chief, emeritus ground music for stores, offices, and BUILD THIS SCA/FM STEREO RECEIVER restaurants; some carry data for per- Larry Steckler, EHF, CET, editor -in -chief ABC's of CET sonal and commercial computer THE and publisher ,,, o users; and some offer special inter- BUt.O A est programming for the handicap- IRe1I0qK WASPr- EDITORIAL DEPARTMENT ped and other groups. This month, SCArFN srcRLo := Art Kleiman, editorial director TRANSISTOR RECEIVER we tell where those hidden signals AAP{.F1ERS l©= Brian C. Fenton, managing editor 110(10T r are, and what makes them possible. Carl Laron, WB2SLR, associate editor CONTROL LANGUAGE 0 © © - Then we'll show you a receiver that Jeffrey K. Holtzman, assistant technical editor CawieferAwer will let you tune into the hidden world of FM radio. The story begins on Robert A. Young, assistant editor *Video News *Now Product. IIi 15.1131 Julian S. Martin, editorial associate *Satellite TV *Aud,o Update page 39. Byron G. Weis, editorial associate M. Harvey Gernsback, contributing editor COMING NEXT MONTH Jack Darr, CET. service editor Robert F. Scott, semiconductor editor Herb Friedman, THE SEPTEMBER ISSUE communications editor Bob Cooper, Jr. satellite -N editor IS ON SALE Robert Grossblatt, circuits editor Larry Klein, audio editor AUGUST 4 David Lachenbruch, contributing editor Richard D. Fitch, BUILD THE VIDEO PALETTE contributing editor Teri Scaduto, editorial assistant Add special color effects to a video signal.

PRODUCTION DEPARTMENT Ruby M. Yee, production director BUILD AN UNINTERRUPTABLE POWER SUPPLY Robert A. W. Lowndes, This 40 -watt back-up supply kicks in at the first sign of trouble. editorial production Andre Duzant, technical illustrator Karen Tucker, advertising production CELLULAR TELEPHONE TECHNOLOGY Marcella Amoroso, production traffic Learn about the technology that's revolutionized mobile telephones. CIRCULATION DEPARTMENT Jacqueline P. Cheeseboro, circulation director R -E ROBOT Wendy Alanko, Part 10 deals with robot applications. circulation analyst Theresa Lombardo, circulation assistant SCR/TRIAC COOKBOOK Typography by Mates Graphics Cover Foto by Bill Peterson, Practical SCR/Triac circuits for your next project. Design Color Labs Radio -Electronics is indexed in

As a service to readers. RADIO -ELECTRONICS publishes available plans or information relating to newsworthy products. Applied Science 6 Technology Index techniques and scientific and technological developments. Because of possible variances in the quality and condition of and Readers Guide to Periodical Liter- materials and workmanship used by readers. RADIO -ELECTRONICS disclaims any responsibility for the safe and proper functioning of reader -built projects based upon or from plans or information published in this magazine. ature. Microfilm & Microfiche editions are Since some of the equipment and circuitry described in RADIO -ELECTRONICS may relate to or be covered by U.S. patents. RADIO-ELECTRONICS disclaims any liability for the infringement of such patents by the making, using, or selling of any such available. Contact circulation depart- equipment or circuitry, and suggests that anyone interested in such projects consult a patent attorney. ment for details.

RADIO.ELECTRONICS, (ISSN 0033-7862) August 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. Advertising Sales Offices listed Second-Class mail registration No. 9242 authorized at Toronto. Canada. One-year subscription rate U.S A and possessions on page100.., $16.97. Canada $22.97. all other countries $25.97. 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 $2.25. c 1987 by Gernsback Publications. Inc. All rights reserved. Printed in U.S.A.

POSTMASTER: Please send address changes to RADIO -ELECTRONICS. Subscription Dept.. Box 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.

2 More Functions. Smaller Budget. Beckman Industrial Circiiitn¡ate" DMMs put hFE, Logic, Capacitance, Frequency and True RMS In Your Hand. For Less.

Get more, for less. It's a simple defi- D.M2O1. Pocket -Size DM850 nition of value. For D\1\Is, value means vaLogic S69.95* True RMS 10-,e041 finding the combination of capabilities that TTL Logic Probe: 20MHz 41/2 digits. DCV accuracy meets your needs at the right price. Without Hi/lo/off indications is .05% +3 digits Detects 25nS pulse True RMS losing sight of accuracy and reliability widths Frequency counter to If you want more functions at a low price. hFE (NPN or PNP): 200KHz Beckman Industrials Circtritmate"I Nepal 1 range (1000) Data Hold display hlultimeters are the best value around. DMM: Input Impedance - capability 10 Megohms Continuity beeper From the pocket -sized 1)\1201. to the DCA/ACA-5 ranges Built-in bail D\1850, with true RIMS capability and accu- (200µA to 2A) Ohms -8 ranges (200 ohms Anti-skid pads racy to 0.05% ± I digit. Circuitmate DMMs to 2000 Megohms) Price: DM850 (True give von the functions mu need. Continuity beeper RMS)....S219.95' DM800 (Average) For instance, the D\1201. puts both a S169.95* Logic Probe, a transistor gain function (hFE). also gives you frequency counting. A full - and a full range of !\'M functions in the function DWI. and more. drxstit have to palm of your hand. For only S69.95. fits in a shirt pocket, yet gives you a full size cost over S169.1+5. If it's a Circuitmate i'/ digit "ii readout. Not to mention a Then there's the 1\1251.. Where else l»1800. complete line of accessories like test lads. does 589.95 buy you a logic Prole, capaci- Or, for a few dollars more. get true RMS current camps. even probes that can extend tance measurement, transistor gain function (AC coupled) to let you accurately meaalre your MINN range and sensitivity All (hFE), and 24 l)MM ranges including resist- non -sinusoidal AC waveforms. and all the designed to work flawlessly with your ance to 2000 megohms? \owhere else. capability of the I)\18(h), in the D\1850. Beckman Industrial Circuitmate D\1\1. When high accuracy counts. there's the Of course, there's a whole range of D\18th) with a -I l/t digit display: The D>18(0 Circuitmate D\I\is and service test instru- lo ments. including the D\I-8 autoranger that I: M1=115 0N DM251. Capacitance, Logic. hFE 589.95' TTL Logic Probe: 20MHz Hi/lo/off indicaticns Detects 25nS pulse widths C11q Capacitance: 5 ranges (2nF to 20µF) yinCUr?MqTe hFE (NPN or PNP): f lo 1 range (1000) r' PWN Continuity beeper Built-in bail É I 0 See your Iiecknlan Industrial distribu- _ N Anti-skid pads tor and discover more DWI performance. 200I moo 780ACV I For less. / '200 i i20 'Su4,e..ted ha price Si1 S1 with hauerc. Iras 'VAIN And nl.uui.Il /2 / i Zoom

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CIRCLE 98 ON FREE INFORMATION CARD WHAT'S NEWS

New infrared systems test New instrument measures tape surface magnetism gallium -arsenide wafers A new device that could lead to mation in this area could lead to The National Bureau of Stan- improved operation of many de- improved magnetic recording dards reports two testing systems vices using magnetic tape has technologies." using polarized infrared light. been developed by scientists at "The trick," Fletcher said, "was They are expected to he especially the Argonne National Laboratory. to make the probe as sensitive as useful in production control of The instrument, called a polar- possible to magnetic fields at the gallium -arsenide (gAaS) wafers. ized -neutron retlectometer, uses surface. This was accomplished by GaAs applications are growing neutrons to measure magnetic sending the neutrons nearly paral- rapidly, but production of the fields over microscopic depths at lel to the surface, so they graze it." near-perfect crystals needed for the surface of materials. The instrument can measure mag- best performance is not as ad- "The instrument has already netic fields within .0002 -inch of the vanced as with the older silicon been used to measure the re- surface of the material. It can de- technology. Detecting flaws in sponse of new recording materials tect a magnetic field change over a GaAs crystals should he easier to magnetic fields," says Gian distance as small as a billionth of with the new systems. One can Fletcher of Argonne. "Better infor- an inch. scan an entire wafer; the other uses a 75- to 600- x microscope to Fa , view smaller portions. Both permit digital image storing and the use of false -color graphics to represent $ variations in characteristics that could point to potential problems.

FCC abandons Consumer q Radio Service The FCC reports that it "has de- clined to amend its rule to establish a Consumer Radio Ser- vice within the 462- and 467 -MHz frequency segments now assigned to the General Mobile Radio Service (GMRS)." That marks the end of an FCC -sponsored plan to replace the GMRS with a service h that many felt would be of far -less value. Replies to a request for comments "tailed to find any specific needs" for such a service, according to the FCC. Moreover, concern was expressed about the fate of present uses of the GMRS, including safety services provided by vol- unteer public service teams such REACT 1 as (Radio Emergency Associated Communications Teams). Consequently, the Commission concluded "that there was no reason to dislocate current GMRS GIAN I'. 1 LETCHER, ARGONNE NATIONAL I AR JRATORY scientist, vs ith the polarized -neuron reftectometer that could lead to improvements in magnetic recording. users" and dropped the Consumer Radio Service concept. R -E

4 Where's Your ELECTRONICS Career Headed? a your.. ove: f .

. 1 .. mat

The Move You Make Today Can Shape Your Future

Yes it's your move. Whether on a chess board Independent Home Study Can Prepare You or in your career, you should plan each move carefully. In electronics, you can move ahead Study materials, carefully written by the Gran- faster and further with a tham staff for independent study at home, are supplied by the College, and your technical questions related to those materials and the B. S. DEGREE lesson tests are promptly answered by the Gran- tham teaching staff. Put professional knowledge and a COLLEGE DEGREE in your electronics career. Earn your Recognition and Quality Assurance degree through independent study at home. Grantham College of Engineering is accredited with Grantham College of Engineering. No by the Accrediting Commission of the National commuting to class. Study at your own pace, Home Study Council. while continuing your present job.

The accredited Grantham non-traditional All lessons and other study' materials, as well as com- degree program is intended for mature, fully munications between the college and students, are in the employed workers who want to upgrade their English language. However. we have students in many foreign countries; about 8IY of our live in the careers . . . and who can successfully study students United States of America. electronics and supporting subjects through r INDEPENDENT STUDY, AT HOME Grantham College of Engineering R-8-87-1 10570 Humbolt Street, Los Alamitos, CA 90720 Free Details Available from: Please mail me your free catalog which explains your B.S. Degree independent -study program.

Grantham College of Engineering Name Age

10570 Humbolt Street Address Los Alamitos, California 90720 City L State Zip 5 VIDEO NEWS DAVID LACHENBRUCH, CONTRIBUTING EDITOR

TV Sets Large and Small.TV sets with giant matching the resolution capability of the new cathode-ray tubes are now included in many Super -VHS system (Radio -Electronics, May, manufactures' lines; at the other end of the 1987) would be unavailable at a consumer price. spectrum are the first active -matrix LCD color Hitachi now says it will deliver.a high -resolution sets. Active -matrix LCD's produce a picture that is Super -VHS camcorder this fall. RCA, whose VCR's vastly superior in terms of resolution and color and cameras are made by Hitachi, is expected to to the passive -matrix type used in the LCD sets come out with a similar version. introduced to date. Panasonic originally showed a sample of its 3 - Menu -Driven TV Sets.Television manufac- inch "Pocket Watch" LCD TV set almost a year turers are borrowing from computers in ago, then shelved it because of manufacturing providing what they see as the very latest in problems. Now it has been introduced in a tuning convenience-the on -screen menu. That somewhat different form-including stereo -FM/ feature is carried to the furthest extreme in the AM radio (with headphones). Because of the new RCA and Magnavox lines, in which virtually inherent expense of producing the active -matrix every TV function may be tuned with on -screen LCD's, as well as the high value of the Japanese indicators and legends. In RCA's Dimensia audio - Yen in relation to the Dollar, Panasonic has put a video line even the FM- and AM -radio tuning is list price of $550 on that little TV set. In addition, done on the TV screen. A typical TV tuning Toshiba plans to offer a 4 -inch active -matrix LCD system gives on -screen indication of such TV this fall, and has said it is "aiming" at a price functions as mono, stereo, SAP (for Second Audio of around $400. Program), bass, treble, balance, input, brightness, On the large screen front, several manufac- picture, color, tint, sharpness, cable or broadcast turers are introducing sets with screens larger tuning, on -off time setting, channel blockout (for than 26 or 27 inches, but smaller than the 35 - parental control), and so forth. The Magnavox inch size produced initially by Mitsubishi, and Total Remote Control system even has a novel later adopted by Sanyo, Sharp, Fisher, and Sears. "channel captioning" system. The user can Panasonic, in its new line, is featuring a 31 - identify each channel by its call letters or inch set, as is North American Philips, which broadcast- or cable -network (HBO, CNN, etc.) manufactures sets under the Magnavox, Philco, affiliation, and any time that channel is displayed, and Sylvania brands, Now Toshiba, the originator the identification also is flashed on the screen. of the FST (Flat, Square Tube), has introduced its Double -Tuner TV sets. Another innovation in FST Magnum, a tube that measures 30 inches, the new models is the two -tuner TV set. The first diagonally, and whose face is virtually flat. The digital TV models, you'll recall, had the picture -in - rest of the industry is choosing up sides among picture feature that superimposes a second the various sizes. Whichever they choose, the new picture in a corner of the screen, but required a types are luxuries indeed, with prices ranging second picture source, such as a VCR, to use the from $2,000 and up. feature. New color-TV sets from Sony and Hitachi get around that by incorporating two tuners. That Super Camcorder. The first combination allows the viewer to watch any two channels camera -recorder capable of making home movies simultaneously, switch them around, halt one to a with higher resolution than broadcast TV or still picture, and so forth. Interestingly, the new videodisc has been announced by Hitachi. Hitachi double -tuner picture -in -picture storage system is says it has developed an MOS camera pickup that digital, but other processing circuits are analog. can produce 450 lines of horizontal resolution, And therein lies another trend in the new which it plans to mass-produce starting this models: Use digital technology where necessary summer. Until Hitachi's development became to provide a special feature; otherwise stay with known, it was believed that camera pickups tried-and-true analog circuitry. R -E 6 TEST EQUIPMENT THAT MEASURES UP TO YOUR

-JDR INgTRUMENT9 SPECIFICATIONS iaa 1.226 -

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DMM-300 $79.95 DMM-200 $49.95 DMM-700 $49.95 DMM-100 $29.95 35 DIGIT DMM / MULTITESTE9 3.5 DIGIT FULL FUNCTION DMM 3.5 DIGI' AUTORANGING DMM 3.5 DIGIT POCKET SIZE DMM °Ur bar model. A highly accurate, full tune High accuracy, 20 amp cunont capability and Autorange convenience or fully manual ;per Short -pocket portability with no compromise iron DMM loaded with many extra features many range settings make this model ideal for anon Smectable LO OHM mode pe -m,3 in features or accuracy. Large, easy 'to read Audible continuity, capacitance, transistor serious tench or r old wo-k Tilt stand for accurate n circuit resistance measurer-eon's .5" LCD display. 2000 hour battery life with -empera-u,e and conductance all in one hand hands-frte operation 2000 hour battery Ile involving semi conductor functions. MEM standard 9v cell provides over two years of held meter -Temperature probe, test leads a lc with standard 9v :ell Probes and battery mode for measurements relative to a specifc average use. Probes and battery Included. battery i rckrded. included reading Probes and battery included. Basic DC accuracy. plus or minus 0.5% Basic DC accuracy: plus or minus 0 25% Basic DC accuracy plus or minus 0 25% Basic D; accuracy plus or minus 0 5% DC voltage- 2v - 1000v, 4 ranges DC votage: 200mv - 1000v, 5 ranges DC voltage 200 --iv - 1000v. 5 ranges DC voltage. 200mv 1000v, autoranging AC voltage: 200v - 750v, 2 ranges AC votage: 200mv - 750v, 5 ranges AC voltage. 200rw - 750v, 5 ranges or 5 manual ranges Resistance: 2k ohms- 2M ohms. 4 ranges Resistance: 200 ohms - 20M ohms. Resistance, 200 slims - 20PA ohms. AC voltage. 2v - 750v, autoranging DC current; 2mA - 2A, 4 ranges 6 rams 6 ranóes . or 4 manual ranges Fully over -load protected AC/DC current: 200uA - 10A, 6 ranges AC/DC current: 300uA - 20A. 8 ranges Resistance. 200 ohms - 20M ohms, Input impedance: 10M ohm Capad tance: 2000pf - 20uf, 3 ranges Fully over -load pr,tected autoran)i rig 130 x 75 a 28mm, weighs 195 grams Transistor tester hFE test. NPN, PNP Input impedance 10M ohm AC/DC wrrent: 20mA 10A, 2 ranges Tempea:ure tester 00 - 2000" F 180 a 86 x 37mre, weighs 320 grams Fully ov at bad protected Conductance: 200ns Audible continuity tester Fully over-load protected Input impedance: 10M ohm Input impedance: 10M ohm 150 a 75 it 34mm, weighs 230 grams

i; - r-+ 1 II'll Iti .,...., , car rTawe*tta 'Teem MODEL 2000 $349.95 2D MHz DUAL TRACE OSCILLOSCOPE r

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000-530-5000110 41112 Knowles Drive Gatos fLos CA 95030 (408) 866-6200 FAX (408) 378-8927 Telex 171-110 OR VISIT OUR RETAIL STORE COPYRIGHT 1966 J06 MICROOEVICES 1256 SOUTH BASCOM AVE. THE JOR INSTRUMENTS LOGO IS A REGISTERED TRADEMARK OF JDR MICRODEVICES JOR INS -FOMENTS IS A TRADEMARK OF JDR MICRODEVICES. SAN JOSE, CA. (408) 947-8881 CIRCLE 59 ON FREE INFORMATION CARD WRITE TO:

Asi R -E ASK R -E Radio -Electronics 500-B Bi-County Blvd. Farmingdale, NY 11735

SUNRISE TO SUNSET cember, 1966, pages 65-75. Be- transistor (Q3) circuit: a relaxation SIMULATOR cause the circuit was designed for oscillator that is coupled to Triac I need a sunrise sunset simulator, 240 -volt operation, some circuit TR1's gate through pulse trans- which is a device that will turn on a values-those marked with an as- former T1. The oscillator's basic lamp slowly to simulate the sun ris- terisk-will have to be adjusted for frequency depends on R7/C4. ing and then, after a preset time, operation on 117 -volt powerlines. The bridge rectifier develops ap- slowly dim the light to simulate sun- Current through a lamp or a proximately 165 volts peak, which set. Do you have anything in your heater load connected to socket is regulated to approximately 13.5 files?-D.E.R., Notre Dame, IN. SOl is controlled by varying the volts by silicon rectifiers D5 and D6 Figure 1 shows a circuit that will conduction period (angle) which are in series with 12 -volt fill the bill. The circuit was pre- through each half -cycle of line Zener diode D8. sented by Jamieson Rowe and voltage applied to the Triac (TR1), Also connected across the 13.5 - Kieth Woodward in the article "An which is connected in series with volt source is Q3's RC timing net- Automatic Lamp Dimmer, Using the load across the AC powerline. work, R3/C2. For proper circuit op- the Triac AC Switch" in the maga- The conduction period is varied eration, R3 must be adjusted so zine Electronics Australia, De- and controlled by the unijunction the voltage across C2 just rises to the conduction point of Q3 at the end of each halt -cycle of the line voltage. Under that condition, Q3 FOR OPTIMUM STABILITY delivers a current pulse through T1 AND RELIABILITY Crystek IN to TR1's gate as the instantaneous FREQUENCY MANAGEMENT line voltage drops close to zero. Since the line voltage is near zero, crystals ,{ no appreciable current flows through the load (connected to QUARTZ CRYSTALS S01) when the Triac conducts. FOR IC The adjustable dimming control Industrial Equipment/Instrumentation R2, is a 10K wirewound potentiom- Micro -processor control rs - Computers/Modems eter. The voltage tapped off R2 Test/Measurement feeds an RC timing network con- Medical COapy5-ct>5 co YO. sisting of R3 and RATE R4 in offirtµ control series with C3, a 100-1.1.F, 16 -volt o General Communications o°r". electrolytic capacitor. The voltage Channel element Service (VHF/UHF) The Land Mobile 2 -way across C3 is applied to the base of a Pulse of Marine Darlington amplifier (Q1 and Q2) Aircraft Dependable Communications Telemetry that uses 2N3565 or similar NPN Monitors/Scanners/Pagers Crystek Crystals otters their new 16 page FREE catalog of crystals an oscillators. Offering state of silicon transistors. The Darling- Amateurs/2-Meter/General Coverage the art crystal components manufactuered by the ton's emitter output is connected latest automated technology. Custom designed or CB/Hobblest/Experimenter "off the shelf," Crystek meets the need, worldwide. to timing capacitor C4 and to the Write or cell today! emitter of Q3. As C3 charges, its voltage is ap- CRYSTEK CORPORATION plied as a "bootstrap" to DIVISION OF WHITEHALL CORPORATION voltage C4. Since the Triac is normally oft, 2351/2371 Crystal Drive Ft. Myers, FL 33907 or nearly P.O. Box 06135 *Ft. Myers, FL 33906-6135 so, we simply cause it to turn on TOLL FREE 1-800-237-3061 earlier and earlier in each PH 813-936-2109/TWX 510-951-7448/FAX 813-939-4226 half -cycle of the supply voltage when TOLL FREE IN THE U.S.A. EXCEPT FLORIDA, ALASKA, HAWAII we want to increase current through the load that is connected CIRCLE 193 ON FREE INFORMATION CARD to socket SO1. On the other hand,

8 fie fourth law of robotics A robot is a robot is A robot shall make robot.... a robot. learning fun for man a was and thereby improve Until HERO 2000. tie quality of life HERO 2000 is much more than a for mankind. '' robot. It's a walking, talking 16 -bit ':omputer. With 64K ROM and 24K RAM expandable to more than half a megabyte. And a fully articulated arm with five praxes of motion. Yours to program. Command. Modify and expand. Total system access and solderless experimenter boards provide almost limitless pos- sibilities. Its remote RF console with ASCII keyboard gives total control. Available with three self -study courses. Backed by Heath Company, world leader in electron c kits. Build your own HERO 2000.Or buy 'd it assembled. Have " , i u fun learning skills - - - ...... that translate HERO directly to the ,"^ world of work.

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CIRCLE 176 ON FREE INFORMATION CARD FAST ON 125 ADJ 7 IMEG -- W R6 3.jMEG RI S1 -w R3 3.3K QI 15K OFF 2N35re5 kR? R8 IOW 3.3 MEG 410 D2 D5 R'4 A2 1144004 IN4004 500K TRI D3 IN4004 R2 RATE C3 J DT 10K 100 Q3 D(o ww i + 16V Q2 1N4004 2N264ry INtiOo4 DIM 2 N 3515 - 4IF< D4 B2 PL I IN40o4 D8 ADS St-b C4 .I n I N 4004 12V pOFF III L Sot

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FIG. 1

to reduce current through the load down time is about 1 minute. Inductor LI is a hash suppresser we DIM control R2 to reduce the Changing R4 to 5 megohms in- made of 50 closewound turns of voltage across C3. That lowers the creases the control range to about No. 18 enameled wire on a 2 -1/2 - "bootstrap" voltage available for 15 minutes. inch piece of the same type of rod C4 so Q3 and TRl begin con- Pulse transformer T1 is wound as used for the core of T1. Insulate

ducting later and later in each half - on a 1 -inch length of/a-inch diam- the coil with plastic tape. cycle of the line voltage. eter ferrite rod. Each winding con- Resistor R7 may have to be ad- When RATE control R4 is 500K, sists of 100 closewound turns of justed slightly for correct circuit the maximum fade -up and fade - No. 36-40 enameled wire. operation. R -E High Quality Lowest Prices TEST INSTRUMENTS Off -The -Shelf Wew! MINI -METERS w/MAXI-SPECS I SCOPE 31/2 Digit Capacitance HITACHI 35 MHz Dual Trace Oscilloscope reprirem SCOPE 31/2 Digit LCD Model $5500 Model V-355 $59995 I - with 8 Full Functions .gym. DCM-602 ti (Reg. 8899.95) Probes included Thin lightweight, Model Test leads included 8 ranges with full $4495 scale values to 2000 uF LSI circuit compact Large 6" rectangular, DVM-632 internal graticule CRT Autofocus Crystal time base Frequency range Deluxe test leads included BOO Hzto8Hz 0.5% accuracy Transistor FORDHAM Sweep Function Generator gain test Audible continuity SCOPE 31/2 Digital Multimeters checking & diode test Model FG-801 10 Amp measurement Model (Reg. 8289.95) $21995 - Test leads included 7 frequency DVM-638 $7995 SCOPE 31/2 Digit LCD ranges, 0.2 Hz to 2 MHz Accuracy Test leads included 11 function, 38 to ±5% Multimeter ;'visualranges Logic level detector Auoibl continuity capacitance and Model $2995 FORDHAM 550 MHz Frequency Counter DVM-6'30 f_i conductance measurement. Model FM -8 Test leads included 0.5% Model Model $16995 $52]5 5Q . . (Reg. 8249.95) accuracy 6 functions, DVM- 634 DVM-636 dV7 Completely assembled, pre -tested, 9 19 ranges Automatic zero 7:111 7 function, 32 ranges 8 function, 37 ranges I precalibrated High intensity 8-digit adjust r Low battery indication Transistor measurement Capacitance measurement LED display Measures 5" x23/4" x%"" _1,!` SCOPE Pocket Sized Audio 111°i- - --s SCOPE 41/2 Digit LCD B&K 20 MHz Dual Trace I(-,.> Signal Generator Bench Digital Multimeter I.; Model Model (1141' * 2M120e1 $39995 RC -555 $4995 Probes included 20 and 26 DVM-6005 19995 dest 9V battery includedl Low /t/ MHz band widths TVV and Test lead set & 6"D" size batteries included 0.4" high distortion sine -wave signal 46 step period: 500 milliseconds NH X -Y operation Trace rotation: adjustable characters Conversion selected frequency x1 range 20 Hz to Automatic, negative polarity front panel Channel 1 output 1.5 KHz/x100 range 2KHz to 150 KHz ZD W Ml Phone orders accepted. Service & Shipping Charge Schedule Continental U.S.A. FOR ORDERS ADD FOR ORDERS ADD $25100 $4 50 5751-1,000 .$1250 $101.250 $600 $1,001-1500 $16 50 Tit 5251.500. $800 $1,501.2.000 $20.00 Fordham $501.750 . . $10 50 $2.001 and up $25.00 260 Motor Parkway, Hauppauge, NY 11788 In New York State 800-832-1446 10 NRI gives you two unbeatable opportunities for top pay, security, even a business of your own.

Everybody wants to get ahead, but most the steady demand for your skills in this people want assurance they're making the field, the U.S. Department of Labor scores right job choice. According to the U.S. a solid hit...high earnings and good job Department of Labor, jobs for electricians prospects attract many individuals... and air conditioning, heating and refrigera- because people in business depend on tion technicians offer high earnings and their air conditioning, heating, and refrig- good job prospects. Now NRI can show you eration systems, the need for skilled tech- how to go after the high earnings, the steady nicians to do maintenance work has to be pay increases, even how to be your own met regardless of swings in the economy. in a your boss business of own. You'll get Add millions of window units in older all the skills to get there. No night school, homes requiring maintenance and repair; no need to quit your job until You're ready heat pumps so popular they're now as to make your move. NRI trains right you at common as furnaces; commercial home in your time. spare refrigeration alone calling for skilled tech- No Experience Needed. nicians to install and service walk-in cool- NRI starts you with the basics, then builds Be an ers, freezers, ice makers, and food cases. your knowledge and skill a step at a time, Electrician Wherever you look, there's tremendous all the while adding practical know-how opportunities for the trained air through hands-on training. You even get conditioning, refrigeration, and heating / ;~ tools you need on the job or in a business technician. of your own. Over a million and a half students have trained the NRI way since 1914. Be an Air NRI training so complete, Be an Electrician. Conditioning, professional tools even included. Each year, the demand for skilled Refrigeration, NRI trains you for this lucrative field, gets construction, maintenance, commercial you ready to land a good paying job, pick and utility Heating electricians continues to grow. Technician. up extra income in your spare time, even The U.S. Department of Labor estimates start a business of your own. You're ready that close to 100,000 new jobs will open up to jump right in because NW includes the in the next ten years -a conservative tools you need: system analyzer, leak estimate compared to industry and union detector, tubbing and joint tools, a top- predictions. quality vacuum pump for purging systems, And few jobs can match the money -making 4 plus demonstration panel units for hands- Ix)tential of the qualified electrician. You on systems training. Graduates of our can earn a salary in excess of $25,000 or Master Course also get optional free be your own boss with your own electrical :7! residential training at the world-famous contracting business. York Institute in York, PA. Only NRI gives you this kind of practi- =`: «5C._ z ® cal, job -oriented, hands-on training. Be an Air Conditioning, Go after high earnings, pay increases, You master practical skills like this with the Refrigeration, Heating a business of your own. equipment, test instruments, and training Send for NRI's free catalog. Find out what materials included in your course... you Technician. hands-on projects you do, the profes- duplicate on-the-job wiring with your NRI When it comes to targeting the good sional tools you train with, and the future Residential Wiring Practical Lab' ...you paying jobs, regular pay increases, and that can be yours. Act today. learn professional troubleshooting using your Volt -Ohmmeter and Clamp -On Ammeter to test the circuits you build up SEND. COUPON TODAY roil FREE NRI CATALOG! "119W-414 on your NRI Circuit Demonstrator...and, by 15` installing and testing an electronic - '

. iIrsKr:-t :.::*i LETTERS LETTERS RAO/O- EL ECTRON/c5 500-B B/-COUNTY BOULEVARD FARM/NGLI4LE, N Y 1/735

LEADER DMM/STORAGE Technology," by Vaughan D. Mar- OSCILLOSCOPE tin, in the May 1987 issue of Radio - I was pleased to see Leader's Electronics. There should be more model LCD -100 I)MM/Storage Os- articles such as that, which give cilloscope (see Fig. I) featured in a good data to the inexperienced. Radio -Electronics "Equipment Re- How else will they be able to port" (June, 1987). While the re- learn?

view was informative, the pricing I would like to add two points: information was incorrect. The ac- One is that we never use any sol- tual price is $850.00, and the unit is dering iron that isn't temperature - currently available. controlled for electronics solder- MARC REINER ing. The old "wood -burning" tools

Leader Instruments Corp. ON SOLDERING are history, but I didn't see any

380 Oser Ave. I enjoyed the article, "Solder- mention of temperature -con- Hauppauge, NY 11788 ing: Old Techniques and New trolled irons; they really aren't that expensive and are essential to good soldering. DOES YOUR DIGITAL CAPACITANCE METER Do THis?I The second point is on tech-

FULL 4 DIGIT 0.5 INCH LCD DISPLAY COMPLETELY AUTORANGING WITH 10 RANGE MANUAL CAPABILITY nique: The iron must always have an AND THIS AND THIS excess of solder in order for the RANGE OF 0.0 pF to 1 FARAD (999.9 mF) IDENTIFIES TRANSISTORS (NPN, PNP( heat to transfer quickly. Get on 0.5% BASIC ACCURACY UP TO 100 uF / AND THEIR LEADS (E, B. C. ETC.) and get oft the AND THIS AND THIS joint; otherwise, READS DIELECTRIC ABSORPTION\ .rr TESTS ZENER DIODES AND RECTIFIERS. the heat will travel away from the AND THIS UP TO 20V ZENER WITH AC ADAPTOR, ZENER VOLTAGE WITH 9V BATTERY joint and heat other areas. Under- EXTENDED PSEUDO 5 DIGIT ° DEPENDS ON ITS CONDITION RESOLUTION ON SOME RANGES ONLY standing heat flow, of course, is AND THIS AUTOMATICALLY what soldering, brazing, and weld- ABILITY TO ZERO LARGE CAPACITANCE CALCULATES LENGTHS OF CABLES IN FEET, METRES, MILES, VALUES UP TO 99.99 uF ing are all about. A good rule of KILOMETRES (THEORETICAL RANGE AND THIS OF 9,999 MILES) thumb would be to apply solder to CALCULATES TRUE CAPACITANCE s, ,-AND IF CAPACITOR IS LEAKY THIS the tip and joint simultaneously- ABILITY TO SORT CAPACITORS IN AND THIS MANY DIFFERENT MODES making contact between the tip DIODE CLAMP AND FUSED PROTECTED INPUT. `-AND THIS and the solder is very important. ABILITY TO DISCHARGE RESISTOR IN OFF READ LEAKY CAPACITANCE (INSULATION POSITION AT TERMINAL INPUTS. RESISTANCE OR CURRENT) Keep up the good work. POWERED BY 9V BATTERY AND THIS GERALD F. DULIN ONE YEAR PARTS & CALCULATES TIME CONSTANTS WITH LABOUR WARRANTY USER DEFINED RESISTANCE VALUES Torrance, CA FOR AND THIS ONLY THIS HOLD FUNCTION FREEZES DISPLAY SHIPPING INSTRUCTIONS: ON PATENT APPLICATIONS

All units shipped out F.O.B. Buffalo NY via United Parcel Service (except Hawaii A. Alaska) I would like to thank David indicated which will unless otherwise (in case shipments be F.O.B. Canada) Pressman for his remarks con- PLEASE SEND ME U.S. FUNDS cerning my article on patents, (QUANTITY) MC300(S) (r 5169.95

CARRYING CASE S 16.95 which appeared in the January, AC ADAPTOR S 9.95 1987 issue of Radio -Electronics. His MODEL SHIPPING AND HANDLING kr $5.00 PER INSTRUMENT App,p.. Slat I (CHECK I (MONEYORDER corrections to details contained MC300 (VISA I IMASTERCARD TOTAL within the text illustrate the need (I CARD NO. for continuous monitoring of pat- 1DAETRON EXPIRY DATE SIGNATURE a division of Bergeron Technologies Inc. NAME ent requirements, and the wisdom 7686 KIMBEL STREET, UNIT 5 ADDRESS MISSISSAUGA. ONT., CANADA of paying an attorney an agent CITY STATE ZIP CODE or L55 1E9 (416)676-1600 to at least review the application. DEALER ENQUIRIES INVITED I agree that the task of applying CIRCLE 200 ON FREE INFORMATION CARD for a patent is not simple, and that

12 Simpson Electric Co. Introduces .The rcei Ultimate in Low-Cost Test Equipment At.last! Here.is your opportunity lo take your pick from a iew test equipmart tine that hesall the features you need and more... and_ at a price that is .mbelievably low.

MODEL 9340 Pocket size, 3'lá -digit MODEL 9670 DMM with 20 reegohm Digital capacitance range and 10 rregohm tester covering 0.1 p: input resistance to 20,000 µF 110500

11111 MODEL 9101 MODEL 9301 Compact VOM with 27 31/2 -dig 1, hand-held ranges, including a DMM with 0.25% 100 megohm range basic accLracy and 11 :2900 F 2,000-hou battery life 369111

Q . ka . . 9r0, ro . /, Y Ye b 4Y MODEM 9120 9ro ` Analog VOM with 12 .A DC range and output

°,Y jack . psr s39' °C :.Y

J ` ro :+. 4 .- C MODEL 9401 Car ./ i Ro 4'/2 -digit, full function, '04 "MODEL 9370 hand-held 'DMM with 3'/2 -digit aitoranging .05% accuracy , and vi DMM with a memory data hold .,e° mode and C.5%'basic $129D0 MODEL 9702 DC accuracy . .01'..-r, digl-clamps^' compact , s5900 AC clamp -on volt -ohm - / ammeter with data hold $7900 Mercer Electron cs products reflect the design and quality standards establ shed by Simpson Electric Company, an industry leader for over EC years and known wprldwide for its integrity mercer and product exce.lence. ELECTRONICS In Stock...Available Now! Stop in at your nearest distributor Division of Simpson Electric Company and see this new, complete line of Mercer test instruments. For the name of the MERCER 859 Dundee Avenue, Elgin, IL 60120-3090 distributor in your area, call (312) 697-2265 Telex 72-2416 (312) 697-2265, or send for our new line catalog.

CIRCLE 205 ON FREE INFORMATION CARD 13 the expression "relatively simple packaged the alarm in a plastic terns tor industrial use. Although I task" (the editor's words, inciden- sandwich box. The alarm worked did not come across a water alarm

tally) could mislead the reader. quite well, even alter sitting tinder that used the SCR circuit, I con-

However, I think that the intent a hot-water heater for more than a cluded that a patent for a water

was to introduce the concept that year. In consideration of patenting alarm would not be profitable. I

applying for a patent is a finite task the idea, I searched the archives of used the circuit as an example in comprised of established pro- the Patent and Trademark Office the patenting article because it sat- cedures, standard form, and a and found numerous patents hav- isfied the need for a simple, easy - structured method of describing ing to do with sensing water and to -describe circuit, and yet one the invention. actuating switches. that exhibited a unique quality.

As to Mr. Arnold's letter con- In addition, I collected advertis- DAVE SWEENEY cerning the water alarm: Back in ing for a number of commercial 1975, I invented a wetness alarm enterprises marketing both water TESTING SEMICONDUCTORS

that used the SCR circuit, and alarms and wetness -detection sys- I was just reading "Testing Semi- conductors" in the April 1987 issue

of Radio -Electronics. I enjoy read- ELENCO PRODUCTS AT DISCOUNT PRICES! ing your articles, because they refresh my memory on how various .7 -7 components work. In the article, you printed an er- TWO ror that is very in the 1.- i:5.1:1. common 100MHz :",--_4 field. In Fig. 1, you are measuring SWITCHABLE t1 R ;17:: I= PROBES r . the reverse current of a diode --"` A 1 INCLUDED 1 using a microammeter (the text - . I ' .-r)(____I1 : e _ I ;*)-_ y .) says milliameter). The reverse current through the diode should be 20MHz DUAL TRACE OSCILLOSCOPE 35MHz DUAL TRACE OSCILLOSCOPE extremely small as compared to the current used by the voltmeter $359 MO -1251 $498 MO -1252 (M2). With some voltmeters, that

Top quality scopes at a very reasonable price. Contains all the desired features. Elenco's 2 year guarantee current is much higher than with assures you of continuous service. Two 1 x , 10x probes, diagrams and manual included. Write for specs. others. It is a good practice, when measuring the properties of any MULTIMETER with TRUE RMS 41 Auto Ranging Mil CAPACITANCE AND DIGIT MULTIMETER WO device, to eliminate any external TRANSISTOR IMI -1 plus TESTER Model - Manual Ranging interference that you can. In the --- M7000 - 3'h Digit Meter Model mad 28 Functions present case, simply placing the i! CM -1500A $65 -t '+ $135 -i-, Fully protected voltmeter before the current :I`1: : Reads Volts, Ohms, .05% DC Accuracy `' the - Current, Capacitors, .1% Resistance e e e M-1180 .7% Acy $36.95 meter would quickly eliminate ~ icy Transistors 8 with Freq. Counter M1182 .25% Acy $39.95 Diodes With case 8 Deluxe Case M-1181 .1% Acy $42.95 problem. I find that many measurements 10MHz OSCILLOSCOPE BREADBOARD GF-8016 FUNCTION GENERATOR in the are inaccurate, clue to with Freq. Counter $199 field iiim Model the technicians involved not $239 Model 9438 " x.21 ¿ __ s-3000 Shown -- knowing how the test equipment r`1Yt,{ Sine, Square, Triangle ------it's Pulse, Ramp, .2 to 2MHz 10MHz DC or AC ---- attects the circuit that being ' Frequency .1 thru 10MHz Triggered Sweep 9430 1 100 pins $15 to. I once witnessed a Calibrated Vert B Nor 2,170 pins $25 connected GF-8015 without Freq.9434Meter $179 Reads Volts 8 Freq 9436 2,860 pins $35 technician connecting a meter a 600 impedance to the DIGITAL TRIPLE POWER SUPPLY DIGITAL LCR METER 50MHz LOGIC PROBE with -ohm Model 20 nsec with memory input of a transmitter. That was XP -765 LP -700 done to measure the audio signal

.--- $195 . _ going into the transmitter. -=-__ is ii. - 0-20V a IA Model However, the meter was con- N N ._!t. gm ' 0-20V a 1A LC -1800 10 - a 5V a SA Measures: nected in parallel to the input, Inductors, 6 $23 Fully Regulated, Short Circuit Protected with 2 Resacoors, producing a 300 -ohm impedance; Limit Cont. 3 Separate Supplies Resistors Logic Pulsar therefore, the signal level was off XP -660 with Analog Meters $159.50 LP -600 $23 by enough to indicate a problem DIGITAL 3 AMP POWER SUPPLY MULTI -FUNCTION COUNTERS with the transmitter, when, in tact, Model ,,,. .,..,.._ _ - there was no problem-just an in- - XP750 -- s -- ter -w1' accurate measurement. $165 o 'n 71 1GHz $245 'Mir ,b, RICHARD P. MORI_EY 1.5A 0-40v0-40V a '; Q,,J stl - o i 0-20V a 3A l- F -too $169 APO, NY rww 100MHz Fully regulated, short circuit protected current limit control Frequency, Period, Totalize, Self Check with High - XP -650 with Analog Meters 5129.50 Stabilized Crystal Oven Oscillator, 8 Digit LED Display PC CLONE Thanks, Radio -Electronics: You C&S SALES INC., 8744 W. North Ter., Niles, IL 60648 15 DAY MONEY finally printed an article, "IBM - 800-292-7711 (312) 459-9040 ASK FOR CATALOG 100 BACK GUARANTEE continued on page 22 2 Year Limited Guarantee! Add 5% for Postage ($10 max), IL Res., 7% Tax 14 CIRCLE 109 ON FREE INFORMATION CARD ti

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.

#708 Toko Coil Set $6.95 Free Reprint with Purchase Above Includes (2) BKAN-K5552AXX, (1) E52OHN- #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 Channel output 2 or 3 switchable F.ne tune memory Microprocessor controlled PLL UL listed/FCC approved operation Simple installation with any TV Skip channel memory Add $3.50 Shipping and Handling eliminates Includes battery and 3 foot coax unused channels $4.50 on Canadian Orders cable ORDER TOLL FREE J J 1-800-227-8529 Inside MA: 61795 8699 LCTRO(HCS,ItIC. VISA, MASTERCARD OR C.O.D.

VISA P.O. BOX 800 MANSFIELD, MA 02048 ri ..uunc .uxu,_ 'Not available( to Massachusetts residents due to state law. copyright 1987 by J8W Electronics. Inc CIRCLE 65 ON FREE INFORMATION CARD 15 SPECIAL BUY ONE VIDEO REWINDERS

Saves Time And VCR Motor Wear! EQUIPMENT . REPORTS

A SOLIDEX° VCR AID! Free -Up Viewing Time that used to be Regency Informant spent rewinding tapes. And, take the work "load" off your VCR's motor with this factory Scanning Receiver new VHS Video Cassette Rewinder by Solidex®. Our special arrangement with the manufacturer makes it a great buy at a An innovation in scanner - remarkably LOW liquidation price! 3 Big Benefits! This "must" device technology CIRCLE 37 ON FREE INFORMATION CARD quickly rewinds video cassette tapes. Extends the life of your VCR's motor. And. helps you avoid costly VCR repairs. Buy NOW! And put this unit to work for you! SCANNERS HAVE NI VI R REl N POPUI AR Using the Informant Reduces Costly Wear on VCR Motor. with John Q. Public. Potential How easy is it to use the Cuts Delays. Lets You Spend More Time scanner butts are often jntim:- Informant? With only two knobs Viewing Tapes, and Less Time Waiting dated by the task of programming and three toggle switches on the on Rewinds. it Fast, Efficient Operation. Auto Shut -Off. a scanner's memory with frequen- front panel, you know can't be Auto Soft Eject. cies of interest, or by the need to too difficult. One of the knobs, of Compact, Space -Saving Size: 21/2"H x buy crystals for each frequency to course, is the volute,) control, 5"W x 111/2"D. LED "On" Light. he monitored. But the scanner in- which also serves as the power 1 -Year Limited Factory dustry could be in fora big change switch. The other is the SQUII..o-I Warranty Parts/Labor. and huge expansion if it follows control. Mfr. List $29.99 the example set by the Informant The I-lol D switch is used to lock INF I, a new scanner from Regency the scanner on a single frequency Electronics (707 interest. Pressing it Liquidation Records Street, In- of once puts dianapolis, IN 46226). the scanner in the HOID mode; " Priced At 1 Item H-2648-7152-291 The Informant promises to pressing it a second time causes Ship, handling: $4.00 ea. make just about everyone a scan- scanning to resume. The HIWAY/ ner enthusiast because it's so easy CI Di' switch is used to select either r Credit card customers can order by to use-even first-time listeners state -police frequencies (HiwAY) or phone, 24 hours a day, 7 days a week. Toll -Free: 1-800-328-0609 will be hooked. The Informant is local city- and county -police fre- Sales outside the 48 contiguous states are subject to so different from other scanners quencies (cITY). The third switch is special conditions. Please call or write lo inquire because it's pre-programmed with the wx SCAN/s TAT l selector. When SEND TO: Item H-2648 all frequencies used by state and wx SCAN is selected, the Informant Elmo Direct Marketing Corp. by 1405 Xenium Lane N/ Minneapolis, MN 55441-4494 local police in each of the fifty will scan the frequencies used Send _VHS Video Rewinder(s) Item H-2648-7152-291 at states. Simply turn the scanner on, the National Weather Service to 519 each, plus 54 each for ship, handling. (Minnesota residents add 6% sales tau. Sorry, no C.O.D. orders.) switch it to your state, and you're broadcast weather bulletins. The sure to hear lots of action. other position is used to select the My check or money order is enclosed. (No delays in processing orders paid by check.) The Informant is so easy to use state whose frequencies you want that it's the to PLEASE almost possible to over- Informant scan. CHECK look its second impressive fea- Rounding out the front panel is a rn Acct No ture: high-speed scanning. two -digit, vacuum -fluorescent dis- U_ Exp/ Z PLEASE PRINT CLEARLY Thanks to what Regency calls play that indicates the state and Ct Name CC TurhoScan technology, the the type of signal (state, local, or Address Apt it Informant otters a scanning rate of weather) being monitored, and JW city 40 channels per second. That's last the scanner's mode. W State ZIP -most scanners on the market to- The Informant covers state, city, Phone ( O day offer a top scanning speed and county police frequencies

Sign Here about one quarter of that. trout 36-47 MHz (VHF I ow),

16 SATELLITE ELECTRONICS TRAINING FROM NRII

Now you can move into home satellite TV and commercial satellite communications with NRI's latest breakthrough in electronics training With NRI training, you'll explore every aspect of satellite transmission and reception as you assemble, install, troubleshoot, and train with the complete TVRO system included in your course. With today's satellite technology, a call to Paris is as clear and as easy to make as a call next door ... executives use video conferencing to "meet" without leaving their offices ... simultaneously, a billion people witness a single event (a soccer game, an inauguration, a benefit rock concert) ... and scientists explore the mysteries of outer space without leaving their labs. These amazing applications of satellite technology have opened lexciting, new opportunities for the technician trained to install, á!. kintain, troubleshoot, and repair satellite communications r. i luipment. tl Explosive opportunities in home satellite TV In suburban backyards, alongside country farmhouses, and atop commercial buildings, satellite TV systems are continuing to expand all across the country. Already there are over a million TV RO (Television Receive -Only) systems in place in the U.S. alone, and experts predict that the future of home satellite TV looks even brighter.

New jobs, new careers for the trained technician By training with an actual TVRO system, you'll come to As an NRI-trained technician, you can on concentrate understand, first-hand, the function and operation of a satellite earth consumer -oriented TVRO equipment, or use your a training to build station. And once completed, your TVRO will provide the career servicing satellite system the equipment that has become so vital in best television entertainment available-direct from the satellite to commercial and military communications to transmit and receive your home. voice, data, and video signals.

NRI brings satellite technology down to earth Train the uniquely successful NRI way NRI trains you thoroughly in basic electronics, communications, It's hands-on training, at home ... designed around the latest state-of-the-art equipment. You discover by doing and television principles. Using the remarkable NRI Discovery Lab® ... and you do it at and your digital multimeter, you perform critical experiments, tests, your own comfortable pace. and measurements. Then, using your NRI Antenna Applications and Built into your NRI training is the enormous experience of our Design Lab, you assemble and test various types of antennas and development specialists and inst actors, whose training skills and matching sections. personal guidance are available to you on a one-to-one basis. You then concentrate on both commercial and consumer satellite earth station equipment, putting theory to practice as you assemble, Make your move into the future today! install, and test the complete satellite antenna system included in Send for your FREE NRI catalog your course. Only NRI can train you at home for an exciting and rewarding career as a satellite electronics technician. And now is the time to act. Building your own home satellite TV system brings theory to life! Send today for your free, 100-page catalog. It details our training Your Drake TVRO system comes complete with 6' parabolic methods and materials, and our more than 72 years of successful dish antenna system, low -noise amplifier (LNA), down converter, innovation in hands-on career training. If the coupon is missing, write receiver, low -loss coaxial cable, and even a permanent polar mount. to: NRI Schools, 3939 Wisconsin Avenue, Washington, D.C. 20016.

SCHOOLS For Career courses McGraw-Hill Continuing Education Center t l: approved under GI bill. 3939 Avenue, DC 20016 R Wisconsin Washingtor, I. II check for details. We'll give you tomorrow. YCHECK ONE FREE CATALOG ONLY O Data Communications Automotive Servicing Satellite Electronics Communications Electronics O Air Conditioning, Heating, Computer Electronics with Microcomputers Industrial Electronics Refrigeration, & Solar Technology Robotics & Industrial Controls Basic Electronics Building Construction i Video Electronics Servicing Telephone Servicing Locksmithing & Electronic Security Electronic Design Technology E., Small Engine Servicing Photography . C Digital Electronics E Appliance Servicing Bookkeeping ,/j Name (Please Pnni) Age OS - Street

Complete TVRO System and electronic test equipment Accredited by the National Home Study Council 10-087 included with your training. LCitytstate2lp 19 Regency Informant INF-1 OVERALL I[1 Alb PRICE EASE allalli EIM OF USEI INSTRUCTION'giumji MANUAL PRICE/ tills VALUE i Famous hi -tech 21314 9 10

atalog 150-163 MHz (VHF High), and 450-462 MHz (UHF). It's packaged A very special computer & in a case that will be at home in just electronics guide that shows about any car (about 1'/ x 5 x 6%2 you what the exciting world of inches) and it comes equipped with a mobile mounting bracket. kitbuilding can do for you. Also included are a DC power cord Challenge. Knowledge. Achievement. Enjoy- for permanent installation in a ve- ment. All of these things are yours when you build hicle, and a cigarette -lighter plug a Heathkit high -quality product. Our colorful, infor temporary installation. formative catalog reflects the years of experience The Informant's simplicity is and technological expertise that make these sure to he a great attraction to peo- things happen for you. ple who are unfamiliar with scanners, and to those who want an ... easy -to -use scanner for mobile e _ use. But simplicity has its disad- Pack Kit vantages, too. Regency not Multi -Mode TNC chose to include a DELAY switch on the INF-I, probably to keep it looking as clean and simple as possible. Without a delay switch, the user

_ Precision Test Inst uments has no control over how long the oft - `ti scanner will wait on a single frequency for the response to a trans- HERO' 2000 Educational Robot and Courseware mission. The Informant waits less Y than a second, and in many cases IBM-PC Compatible __-;` Expandable Computers - Electronic Keyless Doorlock 41 that's just not long enough. The only other thing missing is a In our catalog you'll find over 450 dence and pride that you can only get frequency display. In a sense, it's interesting and useful items - from by building a state-of-the-art product really not needed, but it would be computer hardware and software to yourself. And you're backed by our nice to have some way to identify a robots and test instruments, and from promise, "We won't let you fail:' given channel. home security systems to color tv's The Heathkit Catalog is a simple - Even though a lockOul switch is and amateur radio equipment. and FREE - first step toward this ex- But what makes Heath Company cellent opportunity. not included, it is possible (by unique is that we offer you the confi- using two of the toggle switches in combination) to force the scanner Send t NOW for your FREE Heathkit Catalog to skip an unwanted channel. The Informant INF-I sells for CIRCLE 86 ON FREE INFORMATION CARO $369.95. We can't compare that 1 price to any other scanner on the Yes! I want to see what kitbuilding can do for me. market because the Informant is Please send me the latest Heathkit Catalog Free. unique. When its main features- Send to: Heath Company, Dept.020-562 TurboScan technology and simple Benton Harbor, Michigan 49022 operation-are incorporated in products built for the scanner Name hobbyist, things will never be the Address same. Regency is working on doing that now; by the time you City State Heathkít*m read this, they will have intro- Heath Zip Ea duced new scanners with features Cornv.: r A subsidiary of Zenith Electronics Corporation CL-787R2 - you've never even dreamed of. R -E L J 20 Now test and restore every CRT on the market ... without ever buying another adaptor socket or coming up embarrassingly short in front of your customer ... or your money back NEW ,jJ

n ---- .. -v- LET 11 inieaeAmeeeen

ELECTRONICS PRODUCTS CATA- LOG, includes such items as a color light controller, color LED VU meter, electronic echo and reverberation amplifier, stereo simulator, multi -purpose melody generator, digital clock with two timers, battery fluorescent light, infrared remote -control unit, speaker protection, superior electronic roulette, power supply for microcomputer, and many others. 24 pages. Available on request from Mark V Electronics, Inc., 248 E. Main St., Suite 100, Alhambra, CA 91801. , CIRCLE 38 ON FREE INFORMATION CARD - 4.., ..,.,," . CONSUMERS'S GUIDE TO PRI- MARY BATTERIES, is pocket-size . (31/2 x 7 inch), six -page guide to l the most -commonly used consumer batteries; also some unusual types that are also available with the new improved CR70 "BEAM BUILDER"TM in the average supermarket-such Universal CRT Tester and Restorer as cylindrical, rectangular, and Patented $995 button/coin sizes. The booklet dis- Have you ever? cusses each type and how each should be used to assure the most Thrown away a good TV CRT, data display CRT, or scope CRT that could have for efficiency and safety. It is available been used another two or three years because you had no upon request from National Elec- way to test or restore it? trical Manufacturers Association, Lost valuable customers because you advised them that they needed 2101 L Street N.W., Washington, a new CRT when another technician came along and restored the CRT DC 20037. for them? CIRCLE 39 ON FREE INFORMATION CARD Lost the profitable extra $35 or more that you could have gotten for INTRODUCTION TO PACKET RA- restoring a CRT while on the job and locked in the profitable CRT sale later? DIO, is an I8 -page, letter -sized booklet that explains packet's pro- Avoided handling profitable trade-ins or rentals because you were cedures, operations, and applica- afraid you'd have to replace the picture tube when you could have restored tions in easily -understood terms. it? It is written in a conversational Had a real need to test a CRT on the job, but didn't have the right style, and the contents are adaptor socket or setup information in your setup book? the ques- organized by common If any of these things have happened to you, CALL TODAY, WATS FREE, tions that most potential users ask 1-800-843-3338, for a FREE 15 day Self Demo. about packet radio, such as: What is packet radio? Where is it used? "BEAM BUILDER" is a trademark of Sencore, Inc.

What equipment do I need? How do I operate it?-and more. The Call Today Wats Free 1-800.843-3338 booklet also includes FCC licensing information. It is available SENCORE or upon request from Kantronics, ,J. 3200 Sencore Drive r 1202 E. 23rd St., Lawrence, KS Sioux Falls, SD 57107 innovatively designed 66046. R -E 605-339-0100 In SD Only with your time in mind. CIRCLE 40 ON FREE INFORMATION CARD CIRCLE 177 ON FREE INFORMATION CARD 21 LETTERS found the electronics articles work, made the manufacturing useless. I subscribe to your maga- drawing for the boardhouse, and 14 continued Iron) page zine because I want to learn more drawn the component layout and understand what's going on. wants to get a more concrete feel- Compatible Clone Computer,' I'm a mechanical -engineering stu- ing for electronics. Well, the next (February 1987 Computer Digest) dent. My only connection to elec- step is to stuff boards, get to know

that I can use and relate to. Tha tronics was a sorry two years that I actual components, learn how to one article, to me, is worth the spent learning printed -circuit art- solder, etc. And then get into the three years or so that I have been work preparation from the ground theory as a final step.

carrying a subscription. I want to up. You know-the "make a mis- Radio -Electronics is giving me a

have a computer soon, and I think take and we'll tell you what you did library on those things, the "how

the article was my ticket to getting wrong" approach. I made a lot of to," and the advertisers for the one. mistakes. parts and the tools.

That is not to say that I have Anyone who's taped a PC art- Again, thanks! And I also think that putting the magazine in a mailing wrapper is great-no more mangled covers. CURTIS E. VAILLETTE N O Al idison, WI ElHands.on!K. o ADDITIONAL INFORMATION EIectvonKs.nE 1 e wvwt o nomcs KIWIS,' 11 [see s p` P In response to the question TOUCH LAMP DIMMER Na cS about operating 117 -volt, 60 -Hz -Months equipment on 220 -volt, 50 Hz power lines that appeared in "Ask R -E" in Radio -Electronics, May 1987, Every here's some additional informa-

tion. I was stationed overseas for .yBy1LDESTTIC tour years; and as the staff Elec- BINAURAI tronics Officer, I did a lot of modi- MIKE SET \\ e ..r...r.+ \ IIUW JOYSTICKS WORK fications of that type. TIxICTI SCREEN YOU CAN HAVE THE NEXT TWELVE IS- Most manufacturers have kits TECHNOLOGY UNIQUE ELECTRONICS SUES of Hands-on Electronics delivered to that you can buy that compensate your home for only $18.95 - saving S11.05 off DECIBELS SOUND ACTIVATED the single copy price. for the slower rotation speed of 60- SWITCHES km, wry Fasy Mae Fiz motors when operated on 50 - III I I Issue This EVERY ISSUE OF Hands-on Electronics Hz power. A ditterent-size drive will continue to contain a variety of construction wheel is usually available for most IF YOU'RE THE KIND OF READER that articles to suit every taste. In addition, feature turntables and tape recorders. A your next articles on electronics fundamentals, test equip- doesn't want to wait, you can order -size is copy of Hands-on Electronics now. Hands-on ment and tools will round out each issue. Of different pulley usually Electronics is crammed full of electronic proj- course, Hands-on Electronics will continue to available for motors that drive ects that you won't be able to wait to build for provide new product and literature listings to washers and dryers. yourself. You can expect top-notch digital proj- keep you up to date on the latest developments ects. fun -to -play electronic games, valuable in electronic technology. Clock and tinier modifications add-on computer projects, BCB and shortwave are available for 50 Hz, but are receivers. photographic darkroom gadgets. de- GET IN ON THE ACTION! Order your next hardly worth the trouble. Buy a vices to improve your car's performance, test issue of Hands-on Electronics today. Use the in equipment ideas, and more in every issue of convenient order coupon below. Be sure to send clock the country where it' to be Hands-on Electronics. check or money order-no cash! used. The timers on your washer, dryer, oven, etc. will run a little slower, but they can be set to com- Hands-on Electronics SUBSCRIPTION pensate for that. The resistive load of oven, stove, I I want to be sure I don't miss any issues. Send me ONE FULL YEAR - twelve issues - of Hands-on Electronics for $18.95 (Canada S23.95 U.S. Funds). iron, toaster, room -heater, and clothes -dryer heating elements Payment Enclosed Please charge my will work well on 60 or 50 Visa Mastercard Signature either Bill Me Later Acct.# Exp Date Hz. Ot course, the voltage must be correct. In a clothes dryer, you can Allow 6-8 weeks for the first issue to arrive. ()Her valid in U.S. Funds Only modify the circuit to include a Please print Detach and mail today transformer on the drive motor to: HANDS-ON and timer circuit. That will greatly (Name) ELECTRONICS reduce the size of the transformer SUBSCRIPTION DEPT. that is needed. P.O. BOX 338 (Street Address) Forget operating a TV set MOUNT MORRIS. IL about 61054 built for US video systems and 60 (City) (State) (Zip) ARE 87 Hz: Rent or buy one in the country

22 Walk "tough dog" troubles out of that you're in; modifications are too complicated to get into. any TV & VCR in half the Do not buy transformers in the U.S. to take overseas with you. time ... or your money back There are always people being . transferred back to the States or elsewhere, and who want to get - rid of the transformers that they have. You can save a bundle. Even -" it you buy new ones, buy those 6/011,41,01,11. wound to operate on 50 Hz; they l/W have more iron in them and will e= operate cooler for a given load. Some people have one large i- transformer for the whole house; others have them for individual appliances. Whichever way you IJ go, watch the load. Add up all the possible loads that you will have and get a transformer that's big enough to handle the job. Law.", .... < If you buy equipment overseas, _ be sure that the adapters are available to operate it when you get back to the U.S. Whatever you do for yourself or with the exclusive, patented, for somebody else, if you modify VA62 Universal Video Analyzer ...$3,295 the equipment or change the wir- Would you like to? ing, be sure to document what you have done and what it was like be- Reduce analyzing time: Isolate any problem to one stage in any TV or VCR fore you started. That will be a in minutes, without breaking a circuit connection, using the tried great help at some later date, for and proven signal substitution method of troubleshooting? whomever tries to change it back Cut costly callbacks and increase customer referrals by completely once again. performance testing TVs & VCRs before they leave your shop? Own the I've read your publications since only analyzer that equips you to check all standard and cable channels I was age 12, and that was 60 years with digital accuracy? Check complete, RF, IF, video and chroma response ago; I've been a subscriber for at of any chassis in minutes without taking the back off the receiver or least 30 years. removing chassis plus set traps dynamically right on CRT too? Simplify ROY A. NORMAN alignment with exclusive multiburst pattern? Lcdr. USN Ret. Reduce costly inventory from stocking yokes, flybacks, and other Brunswick, GA coils and transformers, for substitution only, with the patented Ring- ing Test. Run dynamic proof positive test on any yoke, flyback, and integrated high voltage in- or out -of-circuit? HEADLAMP WARNING transformer ... On page 67 of the April 1987 is- Protect your future by servicing VCRs for your customers before they sue of Radio -Electronics a circuit is go to your competition? Walk out "tough dog" troubles in any VCR chromi- shown that warns of the head- nance or luminance circuit - stage -by -stage - to isolate problems in lamps of a car being left on. If the minutes? Have proof positive test of the videc record/play heads before you voltage from the fuse panel used replace the entire mechanism? to power the piezobuzzer and ED Increase your business by meeting all TV and VCR manufacturers' is taken after the dimmer control requirements for profitable warranty service work with this one universally for the panel lights, it is possible recommended analyzer? that there may not be enough volt- To it age to drive those components. prove to yourself, CALL TODAY, WATS FREE, 1-800-843-3338, for a FREE Self Demo ... or learn how the VA62 works first by calling for When I built my own version of a your free simplified operation and application instruction guide, worth warning circuit a few years ago, I used power from the parking $10.00. lamps, which are not dimmed. Though it is unlikely that the car's Call Today Wats Free 1-800-843-3338 fuse block will come after the dimmer control, if that is the case, my NCC) solution is bound to work well. 3200 Sencore Drive KEVIN STEBLETON Sioux Falls, SD 57107 innouatively designed Royal Oak, M/ R -E 605-339-0100 In SD Only with your time in mind.

CIRCLE 178 ON FREE INFORMATION CARD 23 VIDEO TAPE COPY PROTECTION GOT YOU DOWN?

LINE ZAPPER

VIDEO IN VIDEO \" NEW

STABILIZE YOUR PICTURE PRODUCTS WITH THE NEW, IMPROVED LINE ZAPPER STATIC CONTROL, Screen Prep action to remove the insulation Bothered by brightness changes, vertical lumping and consists of two individual, dis- with a slight pull. No sharp cutting littering, and video noise? Tired of renting or buying tapes and being forced to watch an unstable washed out posable cloth pads sealed in twin edges are used, so there is com- picture? Solve your problems with the Line Zapper. toil packets. The first packet con- plete freedom from The Line Zapper accepts direct video from any VCR cut or nicked and monitors the signal, line by video line. When it sees tains a premoistened pad satu- wires. The light -weight handle is the copy protection signal it Zaps it, giving you a normal, clean stgnal at the output. rated with a combination solvent/ heat -insulated with cork. Available In both kit form and fully assembled. The kit anti -static agent that quickly re- is only $69.95 (Not recommended for the beginner) plus $3.00 shipping. Assembled. tested units with a 90 day moves dust, dirt, and fingerprint warranty are only S 124.95 plus 53.00 shipping. oils. The second packet contains a Arizona residents must add 6.7% sales tax. Please yew: k allow 6 to 8 weeks for delivery. Dealer Inquiries dry, lint -tree pad to wipe the sur- welcome. face clear. ELEPHANT ELECTRONICS INC.

BOX 41865-F PHOENIX, AZ 85080 (602) 581-1973 CIRCLE 120 ON FREE INFORMATION CARD

CIRCLE 31 ON FREE INFORMATION CARD

ATTENTION: The model G strips any size down to the finest stranded #36 L__ AWG wire without adjustment. It ELECTRo CIRCLE 30 ON FREE INFORMATION CARD is also suited for coaxial cable and will strip Teflon as well materials Screen Prep also provides a con- with a lower melting point, such as TECHtticimismics venient method for cleaning vinyl, nylon, dacron, rayon, poly- EARN YOUR smudges and stains that result ethylene, etc. It is priced at from equipment handling during $139.50.-Western Electronic Prod- B.S.E.E service calls. It etfect ively removes ucts Co., 107 Los Molinos, San CRT screen contaminants that in- Clemente, CA 92672. DEGREE .. hibit and destroy vision. Packaged THROUGH HOME STUDY in boxes of 24 dual -packs, Screen POCKET MEGOHM METER, the Prep is at $7.50 is a Our New and Highly Effective Advanced -Place- priced per box.- Micro-Megger hand-held, bat- ment Program for experienced Electronic Tech- Chemtronics, 681 Old Willets Path, tery -powered megohm meter for nicians grants credit for previous Schooling and Ilauppauge, NY 11788. Professional Experience, and can greatly reduce the time required to complete Program and -, reach graduation. No residence schooling re- THERMAL WIRE STRIPPER, the quired for qualified Electronic Technicians. 4w 4s Through this Special Program you can pull all of model G, features a continuously loose your electronics background t, the ends of variable heat control that allows 'o. together and earn your B.S.E.E. Degree. Up- -"gr grade your status and pay to the Engineering the unit to strip virtually any size or Level. Advance Rapidly! Many finish in 12 type of plastic -insulated wire. De- months less. Students and graduates in all 50 or *1%%h` States and throughout the World. Established signed for production -line opera- Over 40 Years! Write for free Descriptive Lit- tion, the device can be used either erature. as a bench -operated tool or it can he held in the hand for use in inac- COOK'S INSTITUTE cessible locations. CIRCLE 32 ON FREE INFORMATION CARD ó OF ELECTRONICS ENGINEERING The stripper uses two parallel - p 347 RAYMOND ROAD heating elements to sever plastic testing static dissipative and con- Q P.O. BOX 20345 JACKSON, MISSISSIPPI 39209 insulation, and provides a pincers ductive materials. Featuring a se -

24 CIRCLE 194 ON FREE INFORMATION CARD Exclusive, triple patented dynamic ries of I ED's that indicate surface resistivity, the unit performs over cap and coil analyzing ... guaranteed 1000 surface measurements on a to pinpoint your problem every time single charge. The Micro-Mer,',ger measures or your money back surface electrical resistance in accordance with ASTM D-257; it uses a rechargeable NiCad battery and ... presents no electrical shock haz- s: , ard. It is priced at $249.00.- Gaa rrtMilcr, -,mat Charleswater Products, Inc., 93 w.arw_ ....4.Ct eq t.y .DytrO. y4ri.tt Border St., West Newton, MA =YFr,.t 02165. ... tr ^Duftp,i

ODOMETER DATA COMPUTER, records and stores mileage, date, and time intormation tor up to 60 trips before printing is required; it also keeps a year-to-year mileage total for the current and previous year, and calculates the percentage of auto use for business. It includes a detachable printer.

with the all new LC75 "Z METER 2" Capacitor Inductor Analyzer Patented $995 The "Z METER" is the only LC tester that enables you to test all capacitors and coils dynamically - plus, it's now faster, more accurate, and checks Equivalent Series Resistance (ESR) plus small wire high resistance coils. Eliminate expensive part substitution and time-consuming shotgun- ning with patented tests that give you results you can trust every time. Test capacitor value, leakage, dielectric absorption, and ESR dynamically; with up to 600 volts applied for guaranteed 100% reliable results - it's exclusive - it's triple patented. CIRCLE 33 OF4 FREE INFORMATION CARD Save time and money with the only 100% reliable, in- or out -of-circuit inductor tester available. Dynamically test inductors for value, shorts, and A simple hookup and command opens, automatically under "dynamic" circuit conditions. to the printer produces a printed record that can be submitted to Reduce costly parts inventory with patented tests you can trust. No more need to the Internal Revenue Service. Each stock a large inventory of caps, coils, flybacks, and IHVTs. The "Z METER" eliminates trip's printout includes a purpose time-consuming and expensive parts substitut- section where business activities ing with 100% reliable LC analyzing. can be personalized. Turn chaos into cash by quickly locating transmission line distance to 1 he compact computer, which is opens and shorts to within feet, in any transmission line. illuminated for use at night, can be Test troublesome SCRs & TRIACs easily and automatically without placed anywhere in the vehicle, al- investing in an expensive second tester. The patented "Z METER 2" even though the manufacturer recom- tests SCRs, TRIACs, and High -Voltage Diodes dynamically with up to 600 mends that units such be kept off volts applied by adding the new SCR250 SCR and TRIAC Test Accessory dash due to temperature ex- for only $148 or FREE OF CHARGE on Kick Off promotion. tremes. The printer, which is To powered oft the computer, can be try the world's only Dynamic LC Tester for yourself, CALL TODAY, stored in the glove box, trunk, WATS FREE, 1-800-843-3338, for a FREE 15 day Self Demo. briefcase, or the office when not in use. In addition, several people Call Today Wats Free 1-800-843-3338 can share a printer. SENCC) The Odometer Data Computer 3200 Sencore Drive is priced at $399.00.-Mileage Val- Sioux Falls, SD 57107 innovatiuely designed idator, Inc., P.O. Box 830650, 605-339-0100 In SD Only with your time in mind. Richardson, TX 75083. R -E CIRCLE 179 ON FREE INFORMATION CARD 25 COMMUNICATIONS CORNER Diversity microphone transmission

WE I IAVI DI VOI LI) SI VI RAI COI UMNS In the usual form of diversity re- sarily require vertical and horizon- in the past to the subject of diver- ception, a special receiver switch- tal receiving antennas. In par- sity reception as it pertains to es between horizontal and vertical ticular, FM wireless microphones high-trequency shortwave signals antennas, always selecting the an- can be seriously affected by signal - (to 30 MI iz); those signals are par- tenna input that provides the max- phasing problems caused by mul- ticularly sensitive to variations in imum signal strength. Naturally, a tipath reception. Although the polarization. Although we call the broad range of signal level is ac- problem can usually be resolved ettects of polarization "selective cepted as "satisfactory" to prevent through diversity reception, the lading," in tact the signal might the antennas trom switching hack two antennas involved are both not vary in strength at all; only its and forth continuously. vertically polarized. polarity varies. However, the typ- Rut signal polarization isn't tie For those of you untamiliar with ical receiver sees a change in po- only reception problem that re- the wireless microphone, it is ac- larization as being a change in quires diversity reception, nor tually a system consisting of a signal strength. does diversity reception neces- transmitter and a receiver. The

Pay Less For The Best Floppy Drive WTCPR Weller© Repair & Service Controlled Output Soldering Now the company that manufactures Station floppy drives has set up a repair division. $76.00

Universal Soldering Kit Complete Floppy Drive service for the following: List $28.22 SALE $22.48 Includes dual heat soldering gun with 3 IBM TEAC soldering tips, wrench, flux brush, soldering aid tool 8 solder in plastic carrying case. 8200PK Fujitsu Shugart Professional Soldering Kit Qume Apple List $38.29 SALE $30.50 f`h Mitac Panasonic Includes soldering gun with pre -tinned heavy Weller© copper tip, 2 spare lips, wrench, flux brush, soldering aid tool 8 solder in plastic carrying case D550PK C:7 All repairs are warranteed! We also service on IBM and compatible computers. Service Master XCelite' Roll Kit Send now for your List $95.71 SALE $76.99 Call (408) 988-7510 for more Includes 23 tools in plastic -coated canvas FREE catalog of information case: 6' long nose plier, 5' diagonal plier, electronic tools & or 6" adlustable wrench, regular and stubby bring your service needs to: handles, 9 regular nutdrivers, 3 stubby test equipment nutdrrvers, nos. 1 8 2 Phillips screwdrivers, 3/16'8. Vá slotted screwdrivers, reamers and 7" extension. 99SM First Street Computer Corp. W.S.JENKS & Son lured 3385 Viso Ct. Santa Clara, CA 95054 Ism 1933 Montana Ave. NE Washington DC 20002 TOLL -FREE 1-800-638-6405 CIRCLE 188 ON FREE INFORMATION CARD CIRCLE 66 ON FREE INFORMATION CARD transmitter might be combined Analyze defective waveforms with the microphone into a micro- faster, more accurately, and phone -shaped device, or the transmitter might be independent more confidently - every time of the mike so it can be worn on a money belt or concealed under the user's or your back -.

REFLECTIVE ^- y ` SURFACE

ESrinnuu.0 rv

'+ C HANNEL R .] r WIRELESS RECEIVER OEL TA MEiSUREMENiS TRIGGER

WIRELESS

MICROPHPONE e Tor .a ER/SE+REO FIG. I : p

E NCC7EaE MODEL SCE, vEFOAM 'Nat E2EA B REMOTE ANTENNA i with the SC61 Waveform Analyzer Patented $2,995 If you value your precious time, you will really want to check ELECTRONIC out what the exclusively patented SC61 Waveform Analyzer can SWITCH do for you. 10 times faster, 10 times more accurate, with zero L______J chance of error. FIG. 2 End frustrating fiddling with confusing controls. Exclusive ultra solid ECL balanced noise cancelling sync amplifiers, simplified controls, and clothes. Wireless mikes are used bright blue dual trace CRT help you measure signals to 100 MHz easier by those who prefer to roam unen- than ever. cumbered by the umbilical cord of Accurately and confidently measure waveforms from a tiny 5 mV a conventional microphone. Also, all the way to a whopping 3,000 V without hesitation with patented wireless sensors, which are usu- 3,000 VPP input protection - eliminates expensive "front end" repairs ally wireless -microphone based, and costly equipment downtime. are now built into electric instru- Make only one circuit connection and push one button for each ments as that such guitars so per- circuit parameter test: You can instantly readout DC volts, peak -to -peak formers can also dispense with the volts and frequency 100% automatically with digital speed and accuracy. umbilical cord between instru- It's a real troubleshooting confidence builder. ment and amplifier. In principle, the wireless mikes Confidently analyze complex waveforms fast and easily. Exclusive are much like the inexpensive FM Delta measurements let you intensify any waveform portion. Analyze microphone kits you can buy from glitches, interference signals, rise or fall times or voltage equivalents between levels; in electronics hobby stores for a few direct frequency or microseconds. dollars; those, of course, broad- Speed your digital logic circuit testing. Analyzing troublesome divide cast a signal that can he received and multiply stages is quicker and error free - no time-consuming by a conventional FM radio. Pro- graticule counting or calculations. Simply connect one test lead to any test fessional wireless microphones, point, push a button, for test of your choice, for ERROR FREE results. however, usually pack much more To see what the SC61 can do for your troubleshooting personal productivity power, have a wider frequency re- and analyzing confidence, CALL TODAY, WATS FREE, 1-800-843-3338, high sponse for fidelity, and oper- for a FREE 15 day Self Demo. ate on VI IF frequencies specifical- lv for 1 V assigned stage, radio, and Call Today Wats Free 1-800-843-3338 communications. Because they operate on VHF BENCOR trequencies, they are prone to 3200 Sencore Drive 1 multipath reflections from by steel Sioux Falls, SD 57107 innovatively designed continued on page 37 605-339-0100 In SD Only with your time in mind. CIRCLE 180 ON FREE INFORMATION CARD 27 SATELLITE TV

BOB COOPER, JR., Is HDTV the key to an international standard? SATELLLITE TV EDITOR

IN OUI: LAS I COI Ub1N WI DISCUSSI D A 1 he most logical way to produce plan to gradually phase out the high -definition video is to double 525 -line NTSC national television the picture bandwidth. If a 6-M11z standard. Its replacement would bandwidth is required for 525 -line be a new wideband, High NTSC video, a 12 -MHz bandwidth Definition TV (HDTV) system hav- will certainly accommodate 1,125 - ing more than -1,000 scanning line video. Rut it's impossible to lines. What makes the wideband allow all existing television sta- plan feasible is the concept of sat- tions to increase their bandwidth ellite distribution of television within the existing VHF and UHF programming, which, perhaps, television spectrum because the will ultimately replace terrestrial spectrum is essentially filled to ca- VHF and UHF transmitters. pacity already. Also, the FCC has

* * * * * * * * * * * * * ELECTRONICS JUBILEE 'N MEMPHIS, TENNESSEE Try the

1987 National Professional ladle - Electronics Convention Electronics bulletin board NESDA [Inc. NATESAI, ISCET & TESDA ON THE MISSISSIPPI RIVER system The Peabody Memphis, TN (RE-BBS) August 10-15, 1987 516-293-2283

iffig The more you use It the In MI MI more useful It becomes. Seelel Feenw Spoewwed Mesa Functions Denims We support 300 and 1200 Seminars Menrwwm Teehnkal Rode.., TeNNn, baud operation. FIG. 1 Tare Dey N.Nond Prof ~lone/ Fbee,eonk. Trent Slaw Mud blend Rule Street Ttv. Minktiocrl Flier Parameters: 8N1 (8 data Eg% bits, no parity. 1 slop bill or been chipping away at both the 7E1 (7 data bits. even parity, top end (channels 70-82) and the 1 slop bill. 7ENTAFIVE SCIIEDUL£ bottom end (channels 14-20) of the Add yourself to our user files MONDAY. AUGUST 10 THURSDAY. AUGUST 13 to increase your access. UHF hand for more than a decade, Golf 8 tennis outings Begin 40.hour Instructors/VCR school Trade show Imhuctors Conference and basic VCR ser. NESDA olticer electrons Technical rem mars Country/Western dinner party. siphoning oft UHI channels for M`mcourse Geracrluainted party and Communicate with other R -E nrssmut Rever boat ride (tree to early FRIDAY. AUGUST 14 readers. two-way radio and other uses. registrants; etra

28 sight-under 25 miles). Most favor broadcasts, entirely new studio INTERESTED IN SCRAMBLING? a satellite -to -home approach, and transmission equipment and using the I)BS-assigned 500 -MHz programming had to be created, Bob Cooper's CSD Magazine bandwidth between 12.7 and 12.7 because in addition to the en- maintains a 24 hour per day Scramble - Fax -Hotline telephone service (305/771- GI l,. A few engineers are looking hanced resolution, the aspect 0575) which you may call to obtain a 3 - at the next higher satellite band, ratio (width to height) was minute recorded update on the latest hap- Ka, in the 20-GHz region, because changed as well: trom 4 x 3 to5 x penings in the satellite scrambling world. precise beam shaping would allow 3. (Sony began delivering 5 x 3 Scramble -Fax Newsletter is also published to keep you abreast of the latest tootprint-patterned satellite trans- i IDTV cameras and professional events in descrambling, including sources mitting antennas to cover irregular tape decks late in 1986, and new for descrambling chips and equipment. shapes (such as the state of New procuction studios using that For information, write Scramble Fax, P.O. Jersey) with great accuracy. equipment are already operating Box 100858, Ft. Lauderdale, FL. 33310 or It's that the in telephone 305-771-0505. assumed L.S. will several US cities.) If you have a dish of your own, tune in make the decision to implement the Caribbean Super Station (Western 5, HDTV before 199(1 because that's Back -door standards transponder 23) Tuesdays at 7 PM east- the year that the Japanese expect Al'hough HDTV addresses itself ern for a special weekly Bob Cooper re- to launch a tully operational three - to a better -quality picture, in actu- port. Also tune -in Boresight at 9 PM HDTV the 12 it Thursday nights (Spacenet 1, transpon- channel satellite (in al tact is interlocked with the der 9) for a weekly one -hour report on the 01z -band). Already, new satellite concept ot a global IV standard, activities in the home TYRO field. receivers, television monitors, and for many communications and videotape decks have been people the idea ot a global IV stan- designed to Support their HDTV dard is more important than restrial delivery of HDTV signals, program. When the Japanese inau- hether the TV screen can show meaning that the signals originate gurate the 111)TV service they plan greater picture detail. But the idea trom a microwave transmitting an- to have all of the consumer receiv- of a high -resolution picture has tenna mounted on a tall tower or a ing equipment on store shelves more sizzle and snap than tech- tall building. Virtually nobody else ready for delivery. nica' standards-about which the likes that concept because trans- the revolution at the receiving average user couldn't care two mission ranges would be short end, while spectacular, is hardly hoots-so we will most probably (typically, only direct line of the full eftort. To produce HI/IV continuer) on page 74 Be an FCC LICENSED ELECTRONIC TECHNICIAN!

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MIWONS OF SATISFIED OWNERS Please rush FREE details immediately! 1 NA,1E ADORESS CIRCLE 100 ON FREE INFORMATION CARD e CITY STATE ZIP CIRCLE 108 ON FREE INFORMATION CARD 29 DESIGNER'S N OTEBOOK ROBERT GROSSBLATT, Logic -family translation CIRCUITS EDITOR

I VLI:1BOI)1 11AS I11S FAVORII I IOGW Different supply voltages family. Some like the familiarity of Things get even more tricky it TTL and have never given CMOS a the CMOS and TTL halves of your chance since the bad days of the INPUT circuit are powered by different CMOS "A" series devices. On the voltages. Two readily available other hand, some like CMOS and CMOS bufters (the 4049 and the think that anyone hung up on TTI. 4050) can translate the higher -volt- is from the stone age. I)TL and KTI a age CMOS output into something users are primarily history. the TTL input can use. A sample the truth of the matter is that circuit is shown in Fig. 2-a. To (TI both and CMOS are going to INPUT make the translation without in- be around for a while because verting the signal, use a 4050. each has advantages and disadvan- Going from TTL at 5 volts to tages. It you look at enough sche- CMOS at, say, 10 volts, requires matics, you'll see that many circuit b some voltage translation. We can't designers routinely mix both logic FIG.1 always do it the way we did in Fig. families in the same electronics 1-b because the TTL output must package. be isolated from the higher CMOS There are several considerations +10V +5V voltage. to keep in mind it you want to do There are many schemes to get the same thing in your own de- the job done, but an easy one is signs. Mixing logic families re- shown in Fig. 2-b. A small -signal quires that you pay attention to the NPN transistor is used as a buffer- voltage at which they change state. ing switch between the TTL and TTL parts have much stricter re- the CMOS parts, but keep in mind quirements than CMOS. A TTI low that the transistor will invert the state has a maximum voltage of signal from the TTL output. You about 0.8, and a TTI high state has can re -invert the signal by using a minimum voltage of 2.4. CMOS, another transistor or a spare on the other hand, is much more CMOS gate. flexible. A low is usually defined as less than half the supply voltage, Fanout and a high is more than halt the Before we leave the subject of supply voltage. logic -family translation, we must If you're working with a tive- talk about fanout. If you're a reg- volt-only circuit, mixing TTI and ular CMOS user, you're probably CMOS is simple. As you can see in the CMOS input will change state, used to ignoring fanout limits al- Fig. 1-a, driving a single TTI input so there's no guarantee that the together. The reason is that the in- with a CMOS output requires circuit will work correctly. The so- put impedance of a typical CMOS nothing more than connecting the lution is to add a pull-up resistor of part is so high that you can drive as

two parts together. Going trom about 4.7K, as shown in Fig. I -b. many inputs as you want with a TTI to CMOS, however, requires a The exact value of the resistor de- single output. The same is true bit more thought. Assuming a five - pends on the type of TTL you're when driving CMOS with TTL: A volt supply, the TTI high output using (74, 74S, 74LS, etc.), but a typical TTL output has more than can be as low as 2.4 volts. That's value of 4.7K at least will get you in enough current -capacity to drive slightly below the point at which the ballpark. any number of CMOS inputs.

30 Going the other way, however, is a diversity antenna/receiver system COMMUNICATIONS CORNER bit of a problem. that Shure (222 Hart rey Ave., Evan- The reason is that most CMOS continued from page 27 ston, IL 60202), a manufacturer of outputs simply can't deliver much high-performance microphone current into a low -impedance TTI equipment, calls Diversiphase. input. The number of TTL inputs beams, stage hardware, and any- The wonder of Diversiphase is you can drive with a CMOS output thing else that can reflect radio sig- that it wasn't invented earlier. Fig- depends on the specific TTL part nals. As shown in Fig. I, any re- ure 2 shows how it works. The sig- you're using. As a general rule you flected signals arrive at a wireless - nal is received by vertical antennas can drive more LS inputs than reg- microphone system's receiving an- A and 13, which teed the receiver in ular or S inputs, but it's usually tenna after a directly received one; parallel. To ensure that both an- better to be safe than sorry. So hence, they are usually out of tennas aren't affected by the same don't drive more than two inputs, phase with the directly received multipath signals, at least one an- regardless of type. As a matter of signal. That phase difference can tenna must be remotely located. fact, it's better not to drive more plunge the received signal level Usually, 25 -foot spacing between than one, and make it a 7404 or right into the noise level. As a re- the antennas is best; the minimum 74SO4. You'll have no trouble what- sult, at one moment the audience spacing is 6 feet. soever driving the single input and may hear the performer, but at the However, note that antenna A then following the standard rules next only the lips are seen moving. feeds the receiver directly, where-

for TTL-to-TTF fanout. That's because, when the signal as antenna 13 feeds the receiver If you anticipate designing many strength is too low, the micro- through a 180° delay line that is by- mixed -family logic circuits, work phone's receiver squelches to pre- passed by an electronic switch. out each problem on a breadboard vent the listener's ears from The delay line is a half -wavelength and standardize the design. By possibly being assaulted by the (at the operating frequency) coax- doing so, any time you're faced sound of random noise. ial section. with the same problem, you'll The signals from the two anten- have a debugged module you can Curing multiphase distortion nas always add together, so that drop in your circuit and solve the Multipath distortion plagued when they are in -phase, the total problem. And that will let you go wireless -microphone communica- signal delivered to the receiver is 3 on to more important things. R -E tions until the introduction of a continued on page 78 MI MN MI ill IN mi osc'eC,P9. JERROLD CORDLESS CABLE arñde Itt- TV CONVERTERS KITS OL Ca MODELG STARCOM-460 CONGQME v01-° #, ANY QUANTITY Instant Channel recall = seb8 ~ Volume control Programmable to go on al l 5 68 channels a particular channel and off Mute control automatically Automatic line tuning Compatible with descramblers a 'ADD $5.00 FOR VISA OR MASTE-maR CARD JERROLD CORDLESS CABLE T V 'JERROLD CORDLESS CABLE CONVERTER TV CONVERTER MODEL DRX3-105/400 MODEL DRZ/45O 66 chancels $6995 Automatic line tumn A/B switch oplior.

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The audio answerman LARRY KLEIN, AUDIO EDITOR

II (KAM hII) 10 M1 lECCNIIY IIIAI cases is simply to prevent audio It seems to rue that it each musi- I've been answering consumers' thumps and other noises as the cal instrument in a band or or- hi -ti questions in various publica- circuits charge at the moment of chestra has been recorded with a tions for about 30 years! Ot turn -on. When dealing with vac- specific loudness level relative to course, as times have changed and uum tubes there's an additional the other instruments in that band electronics has advanced, the reason not to have the equipment or orchestra, you want your speak- nature of those questions has also fully on. Tube filaments (like elec- ers to reproduce those levels accu-

evolved. In 1%4, for example, I tric light bulbs) tend to sutter rately, no matter what kind ot cautioned a reader that a metal 616 stress from turn -on surges. It a music is involved. For example, it tube was not an adequate replace- tube is always on (with reduced the recording has been engi- ment for a 61 6GC because the filament voltage), thermal shock is neered so that the brass has an glass GC tube was designed to reduced, and the tube's filament extra "nasal" quality, the bass extra withstand the higher voltages to lite is extended. "sock," and the string extra "bite," be encountered in the new audio Aside from noise and longevity, a speaker with a flat response will amplifiers. some manufacturers claim that deliver those qualities-neither Over the years I've handled there is a sonic advantage in hav- more nor less. In other words, you problems ot stereo and then quad- ing their equipment constantly want a speaker system that is neu- raphonic conversion, advised on on. That may be, but my feeling is tral, rather than having a specific the pros and cons of switching to that any design that needs to be built-in tonal quality. When a transistor equipment, and so permanently powered to avoid a speaker system injects its own to- forth. Today those questions and long warm-up drift needs to be nal qualities-such as an upper- their answers are no longer perti- gotten hack to the drawing board midrange boost-into the music, nent, but new queries have arisen as quickly as possible! In any case, some program material may sound to take their place, so I've as- most manufacturers would advise "better"-hut on most program sembled a group of today's recur- you to turn ott your audio equip- material the contribution will be rent Q's and A's in hope that they ment when you don't plan to use it inappropriate and will only be will he of some aid and comfort again for several hours. heard as coloration.

both to the novice and to the tech- I can see a situation in which a nically beleaguered audiophile. Separate speakers speaker that does a tine job of re-

QI have been told that you producing string quartets is not On -off switching . should use one type of suitable for rock, but only because QShould audio equipment speaker for classical records and it lacks the acoustic -output ca- . be lett on permanently? another for rock. Do you agree pability to achieve the desired Some audiophiles and manufac- with that idea? sound -pressure levels. Achieving turers claim that there is less wear AAbsolutely not! Every speak- an adequate loudness level for on the equipment it it is lett on, . er system should deliver an rock or contemporary electronic and that it also sounds better. accurate acoustic analog of the music can drive your amplifier, ASeveral manufacturers ot electrical signal provided to it by your speakers, or both into distor- . preamps and accessories the amplifier. Those pushing the tion. The distortion may be due to advise that their equipment be concept of ditterent speakers for (I) inadequate amplifier power, switched on permanently. In tact, ditterent music are saying, in low speaker efficiency, or both, or some equipment is designed so effect, that certain types of music (2) inadequate power -handling ca- that its circuits are powered at re- sound best with speakers whose pacity on the part of the speakers. duced voltage even when switch- trequency-response curves, dis- In such a case, other speakers with ed otí, as long as the AC line cord is persion, distortion levels, etc. de- greater efficiency and power -han- plugged in. The purpose in both viate from the ideal. dling capacity would, of course,

32 ("Made in U.S.A." do a better job. However, all other cooling and encoding c ircuits performance criteria in respect to switched off, the signal is likely to frequency range and smoothness, be recorded by the second ma- distortion, dispersion, etc., con- chine at a different level than on CRVSTiiLSJAN tinue to be valid. the original tape. That can confuse I or that reason, a speaker that the Dolbv-decoding circuits dur- Since I can deliver the high volume levels ing playback of the copied tape 1965 desirable for rock reproduction, it because the Dolby reference level We've been supplying quality it is in truth a high-fidelity re- has been shitted. The result will be crystals since 1965 - producer, should do just as good a less noise reduction and some long before the flood of job reproducing the more moder- high -frequency boost (or loss) in cheap imports. ate levels of a string quartet. playback of low-level signals. We're still supplying quality Tape -dub overload Power and volume loss crystals with I have a QWhen I dub some of my Although CD play- Quick Turnaround . records onto cassette, sec- . er, I need a record player Low Price tions of the tape (usually at the for rely 10 -year collection of LP's. I High Quality beginning) suffer from a sort of recently replaced my old phono breakup in the sound every sec- cartridge with a new high -quality TO SOLVE ond or so. When I listen to the unit, but now the power fed to my CRYSTAL disks themselves during dubbing speakers is much lower on phono PROBLEMS. or later, they sound fine. What's than on tape or tuner. Exactly what GET THIS wrong? is the problem? CATALOG AThe records you are trying to AVariations on that question . dub are probably warped . have appeared in my mail at JAN CRYSTALS sufficiently to cause severe vertical least twice a. month for many P.O. Box 06017 The deflection of your phono stylus years. problem-and it really Ft. Myers, FL 33906 during play. That produces a very isn't a problem-is a loss (or a VISA (813) 936-2397 strong, very low frequency signal gain) in volume resulting from a MOW that overloads your tape (or cas- change in equipment: phono car- CALL 1-800-237-3063 sette) deck's electronics. The rec- tridge, tape deck, CD player, FREE (Except Florida) ords themselves sound fine when tuner, preamplifier, power ampli- CIRCLE 104 ON FREE INFORMATION CARD heard through your system proba- fier-in fact, any component. bly because the subsonic warp sig- The "problem" arises partially nal is either handled without because many audiophiles mis- overload or it is filtered out by takenly believe that volume con- components following the tape - trol setting correlates directly with output jack in your equipment. amplifier output power. It does You can test my hypothesis by not! Think of an amplifier's volume playing the problem disks again control as a handle on a water and noting whether warps dis- faucet. If the water pressure (sig- place the phono stylus toward the nal voltage) is very high, then a cartridge body and whether the slight twist will deliver a high vol- warps coincide with the taped ume of water (sound); if the pres- overload distortion. sure is lower, then the faucet has to be opened further to get the same Dubbing Dolby volume of water flowing from it. In QWhen copying a Dolby -en- the case in point, the new phono CHEMICAL . coded tape from one deck cartridge obviously delivers less SOLUTIONS to another, is it better to decode signal to the preamplifier for a FREE CHEMTRONICS CATALOG! the tape playing on deck A and re - given record -groove velocity than Comprehensive new source for over encode it when recording on deck the previous model. 200 products used in electronic man- B, or to record the tape from deck To determine whether the out- ufacturing and field service. Precision cleaning agents, flux removers, bulk A to deck B without decoding and put level of a is phono cartridge solvents, circuit refrigerants, re precision -encoding? adequate, play a record at the dusters, non -residual wipers, foam AYou'll achieve the best re- loudest volume at which you swabs, premoistened pads/swabs, . sults in duplicating Dolby - would ever normally listen to it, antistatic compounds, conformal coat- processed tapes if you decode the and then, without touching the ings, lubricants, adhesives, desolder- rng braids, rosin signal during playback and re -en- volume lift core solder and solder control, the tone arm masking agents. Complete with tech- code it while copying. In other with its cue control. Listen for nical specifications and application words, the Dolby circuits should noise from the phono-preanlp guide. be switched on in both machines. stages. If you don't hear hum, Chemhot Inc.c. If you were to copy Dolby -pro- hiss, or RF buzz, phono gain is Old cessed audio material with the de - within the proper range. R -E C V 11788 516-582-3322 J CIRCLE 54 ON FREE INFORMATION CARD 33 "If you're going to learn electronics, you might as well learn it right!"

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CIRCLE 103 ON FREE INFORMATION CARD 38 L

1 .

DID you ',stow WI'I'lI \ S'I'\Nlh\RI) h\1-hroadeast receiver you can only heat part of the signals available on that hand') SCA/FM-STEREO '11íe rest. called SC'A (Subsidiary Com- munications Authorization) transmissions. ate hidden away on suhea triers and are intended to he received only by certain RECEIVER segments of the puhlie. S( A originated with the k)unding of the 81<-101.1- \11-1z hand in the 1940's. II was intended as an income pnufucer to help l=\1 stations financially until the hand STEREO became economically viable. It has been SCA/FM STEREO Q POWER used for ' arious purposes. such as background music without conunereials for 98 restaurants and offices. for medical news. RECEIVER 92 102 for second -language and prograntnting, TUNE fitr radio reading and news services for the visually handicapped. FM 8( 108 In this aniele we are going to esplore SCA# the world of SCA. We'll discuss. what it is. what makes it possible. and what types of programs and services make use of it. TUNING ON L R \Ue'II also show you how to build an F\1 stereo/ SCA receiver that will let you tune in to all of the signals on the FM hand. But helore we get too far alone. it 0 0 POWER VOLUME PHONES would he helpful to have an understanding of FM -radio basics. I.et's take care of that step first.

FM -radio basics An F\1 (I requency Modulation) signal is simply any RF (Radio Frequency) sig- Tune into the "hidden" signals 9n your FM dial nal k hose instantaneous frequency is de- with this SCA receiver. termined by the modulation. The des tat ion of an F\1 signal is the component of change ni carrier frequency that is RUDOLF GRAF and WILLIAM SHEETS determined hs the amplitude (primarily) and frequency of the modulating signal. FCC wanted F\1 to have the hest possible fore ttzmsntission. and mirror-image In the U.S.. FM broadcast stations are signal-to-noise ratio. FM broadcasting in- deemphasized at the receiver. The end permitted ± 75 -kHz deviation, which is corporates a system of preemphasisi product is a "flat audio response defined as 10119 modulation. Both a 20 - deentphasis equalization. whose param- however noise generated anywhere be- Hz audio signal and a 15-kl-Iz audio signal eters are based on the fact that the high - tween the preentphasis and the deent- can produce 75-k Hz deviation because it's frequency energy of the sounds that are phasis (such as atmospheric noise) is the combination of the frequency and the commonly part ul' programming de- attenuated. Because the equalization re- amplitude of the modulating signal (pro- creases at an almost fixed rate per octase flects natures own frequency charac- gram audio) that determines the devia- a hove 1(1(11) Hi. (That was before the era of teristic:;. it is therefore possible to tion. If one volt of fixed-frequencv audio electronic instruments.) That allows the ()reemphasize say. a concert orchestra that produced ± 75-kliz deviation. then one high frequencies to he ()reemphasized be- is reading 110á/( modulation on a VU tenth of a soli would produce ±7.5 -kHz deviation. Although deviation and modu- WARNING! lation frequency are independent varia- bles. the ratio of deviation to modulation SCA is not a broadcast service, and cases is permitted by paying subscrib- frequency is called the modulation index. SCA transmissions are not intended ers, and under certain circumstances, Or B. where for reception by the general public. As only. Some not -for-profit services do a result, SCA transmissions may be make however, = deviation/modulation frequency use of SCA also, such governed by Section 605 of the FCC as those providing assistance to the In a typical FM -broadcast situation. Rules, which forbid unauthorized indi- blind. It may be possible to receive viduals from receiving such communi- those wihout obtaining prior permis- with a I -k I Iz audio signal at 50V modulation (37.5 -kHz deviation). = 37.5 cations and using them for their own or sion or paying a subscription fee, as other's profit, or divulging their con- long as the terms of Section 605 are (37.5 k l -I z/ I kHz). tents, intent, or meaning to any other observed. We advise you to contact unauthorized individual. the apptoriate programmers in your It's noisy Many for-profit services make use of area for more information and to ob- Because the ear is most sensitive to SCA, and reception of those in most tain any necessary authorizations. log Ii -fueq lie ten noise. and because the

39 fidelity service: its audio -response hand - ratings. and revenue. Stations in those system (an RCA CA31119E can he sub- 9.9

41 R30 1K 02 C6 I R8 40673 18 = R2 .01 1RµH C4 100K R22 R24 C23 a1K 470pF 31- 33K 330f! 01 .6 L2 JOR20 04 D2 1.8 Cl 330f2 71 2N3563 MV2107_;_ t lam DI 2 CI "--;- J8 MV2107 C19 ANT 8pF R4 R6 C8 f- IN C20 .T 10011 1501! C5 10K C C3 T.01 01 I R21 , Ot 47UpF 150(1

R C10 100K C27 100pF .01 =1

22011

R17 R16 C40 C41 C42 C66 IMEG IOK R71 220pf 2J20pF Z26pf 470pf r"NVb--~- 10K IN757 TUNING R18 R48 R49 R50 2.2K 18K _10K ,aK

4C6570pF R13 04 1156 R57 C13 MV2107 3.5K 2N3563 1K 1K .01 NF -

C44 C45 C46 LM565 C17 .001 .1 j .047 2-18pF 1114 1 C16 C14 2.2K 1172 100pF 01 10K 67kHz ADJÚST R55 16V 15K C49 -L-3l+ 10µF C50 16V 0.22 C61 R74 .t TP2 470µF LINE° 10K R68 16V 10011 OUT 11 + c 1 1 J5 = IC3 RIGHT C51 J2 ( 6 047 LM1310N RIGHT C56 C60 la 011T 1 1 1 022 J_ C52 13 .0022 / LED1 STEREO 1 C53 1 C55 J6 J7 0.22 470pF RIGHT LEFT 1163 _ R62 IN 1 STEREO 15K 2 = SCA 1K (?-/ R73 3 =. TUNE C54 10K 4 EXTERNAL 0.41_7 19k Hz L ADJUST 'SEE TEXT S2 FUNCTION

FIG. 2 -THREE OF THE INDUCTORS shown in this schematic diagram must be wound by hand. Even so, they are simple to make; complete details will be given In the next installment of the article.

stituted) IC. ICI. performs limiting and The audio output of the LM3I89N is suhcarrier. That output (about 50 to 100 quadrature detection of the FM signal. fed to an 2N3565 audio amplifier, which millivolts p -p) is the SCA audio. It is and recovers the original audio baseband. delivers an output level of about 3 -volts p- passed through a low-pass de -emphasis R- That IC offers high gain, good limiting. p. That hasehand audio is used to feed the C network to remove high -frequency and low -distortion detection. It also phase -locked -loop SCA detector (an noise. An SCA audio amp (a 2N3565) provides an AFC voltage to correct drift in LM565) and the FM -stereo detector (an amplifies the signal to about 500 -mV p -p, the local oscillator and to aid in tuning a LM I310N ). which is sufficient to fully drive the audio selected station. I)ue to the very high A high pass and twin -T R -C filter de- power amplifiers. gain. layout is ter cril cal and we strong- signed to reject frequencies below 50 kl Iz The LM 1310N is designed to accept the ly recommend using the PC layout that passes the SCA carrier to the LM565. The baseband audio and reproduce the origi- will he presented next time. Otherwise output of the IC is the VCO control volt- nal L and R audio channels. BasebanLl you may leave yourself open to RF-in- age, which follows instantaneous fre- audio of about 2 -3 -volts p -p is fed to the stability problems. quency variations of the 67- or 92-kllz LM 1310N and L and R audio signals ap- 42 1126 1429 33K 330!( R40 10K 05 16 2N3563 R33 C2 FL3 1` 330ft 1134 _ 22K C26 C33 R27 R C.0215± Tr. 8 C22 -1- C28y .01 .01 ? .01 -is ICI .01 - TO R19 R39 ^ . LM3189N : ¡ 109 1509 -r-"'^ METER 11 (OPTIONAL) 13 Xs t C31 732 15 .01 .01 1- i ..4- - T-- = 7 12 1 R35 R43 C34r C35T 4709 10K .01 i 100! 16 I6V C29 I1C36 18pH 10µF

1 R42 Z 10µF 16V 1 4.7K C37 -Ws, 6V t 10UpF

--)127 C39 R44 R59 10uF 22K 10K1-1( ,¡r 16V 0K L7 C47 18µH 10µF 1460 16V ` 100K

C48 R61 05 .0022 10K 1N4001 _ 4 +12V R76 S10-. 1K POWER C64 1E02 R75 470µF POWER 10K J1 16v d HEADPHONES -7 R70 1005! J3 LEFT C63 OUT .1

the pear at outputs. Shunt connected ca- we talk about using the receiver. In the About 500 mV into a 10k load is available pacitors pro\ ide de -emphasis. \n LEI) auxiliary position the unit becomes a at the t !NE OUT jacks. can be connected to the decoder to indi- power amp and will accept an external stereo cate reception. input via its t INE IN jacks. More detail A 3P4T (three pole. 4 throw) switch The dual power amps are identical and Looking at the circuit in more detail. selects among FM (stereo in the case of are built around a pair of LM386N's. FM signals from the antenna are applied stereo broadcasts). SCA. tune; and auxili- Power output is h watt (500 mW) per between the tap on LI, which is the anten- ary positions for input to the dual power channel. That is sufficient to drive a pair na coil. and ground. The antenna coil is amps. In the tune position. FM main of small speakers. but we recommend tuned by CI and varactor DI to the signal channel audio is input to one of the amps using stereo headphones for best results. frequency. The varactor has a variable while SCA audio is input to the other. If desired, the LM 386N amps can he back bias of 1.5 to 8 volts across it. That That makes tuning in an SCA subcarrier omitted and the outputs fed to the line will sweep its capacitance from 15 to 30 easier: more details will be provided when inputs or tuner inputs of an audio system. pF. \\hen that capacitance is added to the

43 stray capacitance on the hoard and the Ti input capacitance of QI . it yields a tuning 16-181/t500mA range of 57-109 MFI,.: that is nutre than sufficient to Cover the complete FM 09 14) broadcast hand. 1N4001 Capacitor ('2 provides an RE ground 106 +12V LM7812 and allows I)(' bias front the tuning -volt- D8 b7 = age line to he supplied through RI. It also C68 C C69 01 I cleans up any noise present on the tuning ° 1 C67 C70 voltage line. No IX' current (lows in RI. 2200µF 470µF 25V 16V and therefore there is no voltage drop across that component. 1 The tap on 1.1 is placed so that ( ) I sees a high input impedance. Transistor Ql is a FIG. 3 40673 \MOSFI.T device with a noise lig- -THE CIRCUIT REQUIRES a regulated 12 -volt power supply. The one shown here fills the bill nicely. uieof4dRor less (tepicallt 2-3 till at FM frequencies): that ensures high sensitivity and there is no base -emitter junction to RF input signal) is about 12 to 15 dli. ply line by R32, R3I. C24. and ('23. cause unwanted rectification of strong sig- depending on local oscillator drive level. Resistor R3() is used to determine the op- nals. Resistor R4 and capacitor C3 'Hie local oscillator uses a 2N3563 tran- erating points of Q4 and Q5. It results in a provide biasing and RF grounding for sistor. Q3, whose operating point is 4 + 4.5 -volt supply to those stages. form- Qt's source terminal. The (i2 terminal is volts at 1.5 milliamperes. That operating ing a voltage divider with R3I and R32. biased at about -F 4 volts by R2 and R3. point is established by the network com- The IF signal is coupled to the limiter/ and C4 bypasses that terminal to ground. prised of R 12. R13. R 14. and R 15. Note detector stage (ICI and peripheral compo- I he gain of the stage may be controlled by that the local oscillator is actually a volt- nents) by FL3. The three ceramic filters reducing that bias to -2 u,lts (cut-off) 'tit- age controlled oscillator set up to be in the shape the IF ba itdpass of the receiver. AGC purposes. Ilowever..\(i(' was not common -base mode at RI: frequencies. They are fixed tuned and no alignment is necessary in the receiver. and was not \t such frequencies. C14 grounds the required. used. The drain is biased through R(, and base of Q3. The gain of Q4 and Q5 is about 26 to 30 L2 to about + II -volts DC'. Drain current Inductor L4 is an RF choke that is Lsed dll. That gives a total gain so far. from the (which is exactly equal to the source cur- to feed DC voltage to the collector of Q3. antenna. of about 55 to 6(1 d13. ensuring rent) is about sir to eight milliamperes. Capacitor C15 couples the tank ciruit that the front-end noise will cause limiting Resistor R5 limits the stage gain to made up of L5. CI7, and 1)4 to the collec- in ICI. The maximum output of Q5 is about (t times. That is the optimum tor of Q3. That tank circuit is used to about 0.25 volt, which is the saturation amount of gain to ensure circuit stability: determine the oscillator frequency. which point. no matter how strong a signal is it is quite adequate to override mixer should be 10.7 Milt above or below the received: ICI can easily handle that with- noise. vet not so high as to unnecessarily signal frequency. In this receiver. the local out distortion. No AGC was found neces- overload the mixer on strong signals. Fur- oscillator operates 10.7 MHz above the sary in this receiver. ther. it allows about a 3-d13 margin fitr incoming signal. There litre, it must tune Most the functions of an FM IF system ntistracking and errors in alignment of the front about 98 to 12(1 11Hz. The spacing are provided by ICI. That device includes tuned circuits. should be 10.7 MFIz over the entire tuning a three -stage limiter. signal -level detec- Capacitor C(, couples the RE signal to range of 87-11(9 MHz. Resistors RI6 ant-I tors. a quad rattire detector, and an audio 1.3. which seises to tune the mixer input. 17 are used to couple the .\FC correct ion amplifier with optional muting circuit Capacitor C'5 is an RF bypass and resistor voltage to the tutting line. eliminating the (squelch). It has its own internal reg- R( dccouples the RF stage from the + 12 - need liir a separate AFC tuning diode. ulators live DC voltages, and can drive an

volt line. the value of RI(, can be anything from I K external tuning meter. While we specified The mixer -input tuned circuit is tuned to I001K. depending on hove much AFC is using a National LM3519N, an RCA by ('7 and 1)2, w ith stray circuit capaci- desired. We used a 10K unit. CA3159E is pin -for -pin compatible w ith tances once again playing a role. Ideally. .\s previously mentioned. L5 and C19 that device and can he used in its place. total capacitance in the circuit is exactly match the mixer to ceramic litter FLI. Use whichever IC is easiest titr you to equal to that in the antenna circuit. Those components also help prevent un- find. However. the operating Q is a little higher wanted VFIF components from leaking Input signal from FL3 is applied to pin

(about 3(1). The overall RE bandwidth is into the IF stages. w high could cause spu- I of ICI. R33 is a bias resistor and also about 2 to 3 \tI-lz. which provides quite rious responses. .\ ceramic filter is a terminates FLI. Capacitors C25 and C26 adequate image rejection -about -3(1 piezoelectric den ice that is the equivalent are RF bypass capacitors. 'Ihe 12 -volt sup-

till or better. of all IF transformer. It acts as a double - ply line is connected to pin 11 of ICI by The mixer is driven by a signal of about tuned translitrnter with a I-dll bandwidth R 19. C31, R39. and C32: those compo- 3-4 volts p -p on (12 of Q2. Since the of 25(1 kHz. centered at 1(1.7 Milt. The nents provide RF decoupling as well. trutsconductance of the -4)I673 is a func- device's insertion loss is about 6 lU. and While they are not used in the receiver. the tion of the G2 voltage with respect to the its termination impedance is specified as IC's squelch (mute) circuits must he ter- source. the local oscillator (more on that 330 ohms. minated: R34. C28. C29. R35. and R36 in a moment) signal in effect modulates The first IF amplifier is built around serve that function. the tratlsconductance of Q2. That results Q4. That transistor is biased by R22. R23. An optional tuning meter can he in- in the 4(673 acting as a niixer. Resistor and R25 to about 2 milliamperes when the stalled in the receiver. Vie chose not to do RS returns G2 to I)(' ground. Resistor R9 collector voltage is 4. Ceramic riper I1.2 so. but if you do. install it at the junction and capacitor ('9 provide about a 0.b -volt couples Q4 to Q5. which is biased identi- of ('30 and R37 as indicated in Fig. I. bias. which places both gates at about cally to Q4. using R2(í. R27. and R25. Otherw ise. the junction makes a good test -(0.(, voh. with respect to the source ter- Capacitors ('21 and C22 bypass the emit- point for ahgning of the front -end's tuned minal. The power gain of the mixer (the ters of Q4 and Q5 respectively. the IF circuits. ratio of the IF signal at 1(1.7 MI -Ir to the stages are decoupled from the power -sup- continued oil /)Ug(' 8/

44 J

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MpN ROSS ORTMAN oils seT

Versatile Digital Timer

You don't need a fancy microprocessor-based timer to turn a device off and on several times a day. This easy -to -build and inexpensive timer will do it with no hassle!

TIMIiMS C'ONTkOI. EVERYTHING FROM SE- powered by the module, it cannot deliver Fuse Fl protects not only the transformer curity systems to computer systems to col: any appreciable current. Therefore the and circuitry. but also the Triac. If a de- tee makers-the list goes on and on. control voltage is fed to a transistor switch vice tries to draw more current than the Timers vary in sophistication from simple composed cf QI. Q2. R3. and R4. The Triac can handle. the fuse will blow. thus mechanical devices to microprocessor - switch circuit in turn controls ICI. an saving the Triac from damage. If you use a based controllers. But there is a middle MOC3010 optocoupler. which isolates Triac with a larger current rating. he sure ground. A low-cost module allows you to the power-control section from the rest of to install a fuse of the proper site. build a high-performance unit that oper- the circuit. Other types of power -control circuits ates like a VCR timer, is inexpensive, and 'Ile power-control section is composed are possible: several examples are shown is very easy to build. The tinier allows of Triac TRI. current -limiting resistor R5, in Fig. 2. An SCR -based circuit is shown three on/off set points per day. and it can and an MOV (Metal Oxide Varistor). The in Fig. 2-0, and a relay-based circuit in control any device that draws as much as 6 latter protects the triac and the op- Fig. 2-b. If you use a different circuit, he amps of current. If the timer's output ca- tocoupler from power -line spikes and sure to isolate the timer module from the pacity is insufficient, you can easily add transients caused by highly Inductive voltage being switched. And whether you an output switching device with greater loads. use a relay. a Triac; an SCR, or some other capacity. The timer can he built for about The power supply is composed of TI, device. he sure it can handle the max- $60 using all new pans. DI, and CI: it provides nine -volts I)C that imum current the device you want to con- powers the switch circuitry. It can also he trol will draw. How it works used to trickle -charge a Ni-Cd battery. Ihe timer's schematic is shown in Fig. Although a regular lead -acid or alkaline Construction fhe heart of the tinier is the PCIM 2303 battery will last ti rquite some time. a 1.5 - The timer circuit is simple enough to be LCI) timer/clock module, made by I'CI volt rechargeable battery will give best wired using point-to-point techniques: (Printed Circuits International. 1145 results. The 1-rnA trickle charge supplied but for a cleaner layout. PC hoards can he Sonora Court, Sunnyvale. CA 94086). by optional components D2 and RI used. You can purchase pre -etched and The 2303 nodule contains the timer IC, should increase battery life indefinitely. If drilled boards from the source mentioned clock crystal, an LCD display. and all those components are not installed, never in the Parts List: alternatively, foil patterns support components. It requires only 1.5 apply power to the unit without a battery for etching your own hoard are shown in volts and draws a maximum of 10 µA. in place. or damage to the PCIM 2303 PC Service. As shown in Fig. 3. the dis- That low power requirement allows the module may result. play hoard contains the timer module and module to he powered by a single AA The specified Triac is rated at 6 amps. If SI-4. The main hoard, shown in Fig. 4, battery. which makes it great for use in that is inadequate for your application. a contains the power supply, the battery, the portable equipment. larger one can he used. Regardless of switching circuit and the output circuit. If 'Ile module has a single output that is which Triac is used, it will generate heat. you use a different output -switching cir- high during the on period and low during so provide an adequate heatsink and ade- cuit you can alter the design of that hoard the off period. Because the output is quate ventilation to avoid overheating. to fit your application.

F1 6A Ti 250V

300mA

D1 IN4001 117VAC

R1 02 R2 - - I 4.7K IN4001 47052

+ Cl R5 I 1 61 220pF 18057 S01 S1 16V E

SET -Z . -O O R4 2i HRS 100K 0 .Z g TRI O MOV1 -Z PCIM 2303 HN O ©D2 L c1 M R3 2N3906 OC3010 S4 I 47K MAN Z 1 O O 1M 01 2N3904 DISPLAY MAIN LOARD J LO ARO

FIG. 1-SCHEMATIC DIAGRAM OF THE TIMER. The PCIM 2303 timer module contains all timing circuits and an LCD display.

An excellent case for the tinter is men- ule (and the attached I'C hoard ti ith tioned in the farts I.ist. II. you use the switches) is glued from behind to an SO1 specilied case. note the lini ted clearance opening in the front panel. SWITCHED R5 OUTPUT between the bottom of the PC hoard and the case. Be sure to insets a piece of tish- Testing paper (or some other insulator). between After mounting all components. in-

the hoard and the bottom of the case to spect your k ork carefully Ibr open solder avoid shorts-and possible shocks. joints, solder hridges. etc. Correct any Note. in Fig. 4 and Fig. 5. the small mistakes. strip of PC hoard material glued to the top Then insert a battery into the holder, of the main hoard behind the display being sure to observe polarity. Now press hoard. That strip reduces stress on the the SF.T and %IAN buttons simultaneously nodule and prevents the display hoard to reset the nodule. lithe module doesn't 117VAC from bending when the pushbuttons are display anything, re -check your wiring. a pressed. 'Ile remainder of construction is After you get the module to reset, plug straighttbward. In our prototype the moo - the line cord into an AC outlet, and plug a table lamp (or other electrical device) into Sol and press the nnAN button. The light should turn on. If it doesn't, check the p_T_ 54 \ Q SET module's Output pin. It should have about

I. I volts on it. If it does. slake sure that Q S3 and Q2 are turning on and enabling the O HRS LED in ICI. If the LED is turning on. you should measure about 1.4 volts across it. Z S2 O p MIN If the LEI) does turn on. the problem lies with the AC portion of the circuit. Be very. S1 +V O ?MAN careful s1hen troubleshooting the AC b f- section, because it has 117 -volts AC GND FIG. 2-AN SCR (a) OR RELAY OUTPUT (b) driv- across it. Check for ss iring errors; other - er can be substituted for the triac output circuit TO v ise. the triac may be had. in Fig. 1. FIG. 4 After you get the circuit working. as- Stuff the hoards in the usual manner. TIMER/ semble the case. The timer is now ready to CLOCK starting with the low-profile MODULE go to work for you in whatever application components. OUTPUT MODULE and working up to the larger ones. The you see M. timer module contains C\1OS circuitry, so handle it with care. Be sure to observe 11) Operation the polarities of capacitor and the sem- Programming the is CI FIG. 3-THE TIMING MODULE and four switch- tinier very similar iconductors. Install the Iranstormer last. es mount on the display board, which connects to programming a VCR tinter. At initial staking sure that it is installed correctly. to the main board via three wires. power -up, the des ice must he reset. That's

46 13/32 PARTS LIST All resistors are Y. -watt, 5% unless oth- ++v erwise noted. SEE R1-4700 ohms ' 9/32 w-. GND TO TEXT R2-470 ohms FIG 3 R3-47,000 ohms o MODULE OUTPUT R4-100,000 ohms R5-180 ohms R3 81 Capacitors C1=220 µF, 16 volts, electrolytic Dl i1 I vOl Semiconductors -- D2 R,4n02 ICI-MOC3010 Optocoupler (Radio + ICI Shack 276-134 or equivalent) -R2- D1, D2-1N4001 rectifier diode Q1 -2N3904 NPN Transistor z Q2-2N3906 PNP Transistor TR1-6-amp 400 -volt Triac (Radio Shack R5 276-1000 or equivalent) MOV1 Other components 131-1.5 volts, rechargeable AA battery 117VAC F1 -6 -amp, 250 -volt fuse TR1 MOV1-117-volt metal oxide varistor (Ra- dio Shack 276-568 or equivalent) St-S4-SPST, momentary, normally open S01-chassis-mount AC receptacle T1 -6.3 -volt 300-mA transformer (Radio - S01 Shack 273-1384, or equivalent) Mkscellaneous: PCIM 2303 timer/clock FIG. 4-STUFF THE MAIN BOARD as shown here. Three wires connect to corresponding points on the module, chassis -mount fuse holder, bat- display board, as in Fig. 3. shown tery holder, line cord, case (Radio Shack 270-286). Note: current time, which is indicated by a the following are available from Dakota Digital, R. R. 1, flashing colon. The programmed timer Box 83, Can- istota, SD 57012: display PC board, will now turn the device you connected on $3.50; main PC Board, $9.95; and off at the preset times. PCIM-2303 module, $23.95; module The xtAN button allows you to override and four pushbutton switches, $26.50. the present state of the timer manually. If All orders add $1.50 for shipping and the output is off when the MAN button is handling. South Dakota residents add pressed, the output will turn on. Con- appropriate sales tax versely, if the output is on, pressing the \IAN button will turn the output oft. After pressing the MAN button, the state of the house can he made to look "lived in by DISPLAY output remains constant until the MAN turning the lights on in the for a BOARD P morning STOP button is pressed again, or until a preset preset lime and turning them on and off FIG. 5-THE COMPLETE TIMER CIRCUIT ap- time forces the output of the timer into a seseral times during the evening. If sever- pears as shown here. Trim the PC board so that different state. al timers were used to control different it fits into the case properly, and insert a sheet of The MAN button controls another im- lights Insulating paper between the board and the bot- throughout a house. the effect tom of the case. portant function. It can he used to override would he even greater. the pre-set times. For example. to over- Other items can he controlled. For ex- ride the first on time, advance the set ample, you could turn your coffee pot on accomplished by pressing the ser and mode until the first on time is reached and in the morning 10 minutes helore you get MAN buttons simultaneously. Then the press the MAN button. An X will appear in ur. Then you could always have your correct time must he entered. Press SE- the display; it indicates that the first on morning coffee first thing. You could also once to enter the set mode; a flashing T time has been overridden. The tinier will control your heating system with the will he displayed. Now set hours and min- then ignore the locked -out set point until tinier, heating your house only while utes by pressing the HRS and MIN buttons it is "unlocked- by repeating the lock -out you're home and awake, and turning it off as appropriate. The displayed hours for sequence. during the day while you're gone and at minutes) will advance once for each press night while you're asleep. The money of the button; if you keep the button Applications saved doing that will add up quickly. pressed, the display will advance continu- The timer is versatile, so its applica- During the winter. in cold climates. the ously at a rate of about two digits per tions are virtually limitless. As a stereo timer could he used to turn your car's second. tinier, the unit outperforms most commer- engine -block heater on in time to warm By pressing the ser button again, the cially available systems. The timer could the block up enough for sale usage. first on time can he set in the same way he programmed to turn your stereo on in Of course, the PCIM 2303 can he used that time is set. Then press the set button the morning, turn it off just after you leave in many other applications. It's a versatile again to set the first oft time. By con- for work or school, turn it on just as you device and it can he used in countless tinuing to press the sir button, the second are getting home, and turn it off after you applications. Whether you're replacing an and third on and off times can he pro- have gone to bed. existing timer or designing a tinier system grammed into the unit. After the third off The unit could also he used to control tilt- a custom application, the PCIM 2303 time is set, pressing the sir button once house lighting for convenience or se- clock/timer module is the ideal starting more returns the unit to displaying the curity. When used as a security device, a point for many designs. R -E

47 L J EQW

S HIGH

_T1 im DEFINITION!

ie s - . TV

! a

(1111111.4111141.

...... _. . ' daft -

The most important change in TV technology since it was invented is just over the horizon.

JOSEF BERNARD

('I:tiA'rnI) NIiUN I.\Ndl'S \NI) \'Ili\y lira) of High -Definition 7V (HDTV) systems of TV viewing. the image must subtend a thruush a spinning spiral of holes in a that will add realism and detail to the iewing angle of at least 30°. To obtain Nipkow disc, the very first TV images images ue v iew for entertainment and in- such an angle, one could simply sit closer were so crude that they:hateI allo\\cd the formation. to the screen. However, at a distance of viewer to distinguish light from shadow. HDTV technology exists today: it is less than 7 times the image height. scan Todas we are much more fitrtunate--on- used. titr example. in Hollywood for spe- lines become noticeable and give the im- screen resolution of several ¡Mildred lines. cial -effects work in TV. By as early as age a grainy appearance. both horizontally and vertically, permits MO. Japanese broadcaster N Elk plans to Figure I compares the geometries us to read street signs. subtitles, and have an HDTV system in place and opera- provided by vievying both conventional mo\ ie credits on color CRT's or I.CI)'s. tional. And work here. in Europe. and TV and IIl) [V screens from the distance Even so. we're always aware that we're else\\ here is progressing so first that sys- at which scan lines are rendered invisible. looking at a television picture. that is, a tems tray he in place world\y ide shortly In a conventional system. the viewing an- picture displayed on a screen. And when thereafter. In this article we'll examine the gle is only about 10°, but an HDTV sys- we can not discern the liner details in an Japanese HDTV system and others. see tem provides the desired 30° viewing image. no matter how hard we strain. the how they evolved. and learn about v\ hat angle. shortcottu igs of the current s\ stem be- obstacles remain before they can become As shown in the figure. if the number of comes evident. 'l'hat is true whether the adopted hir widespread use. scan lines is increased to 100(1 or more, system in question is the NTSC system the minimum viewing distance is reduced used in this country. or the slightly higher- HDTV criteria to about 3 times the image height. At that resolution PAI. and SI'.CAM systems that One of the goals of HDTV is to create a distance a 30° viewing angle can he have hceti adopted by most of the rest of sense of realism for the viewer that's at achieved. Further, due to the limited reso- the world. least as good as that provided by motion - lution of the human eve. the lines will But help is on the way. Dramatic im- picture film. Itov\?Tests have shown that. blend together and give the impression of provements are on the horizon in the form to overcome the ''picture-in-a-hox'' effect a smooth image.

48 r\ PC \I digital audio signal to he multiple \ell with the video signal.

NlLJSl: is known as a "motion -compensated suhsampling.. system. The terms ;id/sun/piing and sub-t\'yyuise refer to the fact that when the ideo information is processed. fewer samples are extracted front it than would he the case if it x ere to he processed using conventional methods. where sampling occurs at twice the

highest frequency ( i. e.. the Nyquist fre- que'ne-s) involved: the lower sampling rate is the reason why that method is called suh-Nyquist. the principal trick used by the \lUSIE system is that it sub -samples the video signal over a Mur-field sequence prior to transmission: the sampling pattern used is shown in Fig. 3. that technique allows for the 4:1 reduction in required bandwidth. Reconstruction of the MUSE signal require.; an HDTV receiver equipped with a memory capable of storing the four fields. For still (non -nerving) parrs of an image. the piclrne can he reconstructed using samples from all four fields since there will he no movement from field to field. CONVENTIONAL TV Hut where there is movement. attentpt-

HDTV

PANAVISION-5:5511 85 1) FIG. 1-THE GEOMETRY OF TV VIEWING. With an HDTV image, a viewer can sit closer to the screen to attain a greater viewing angle, thereby improving the sense of realism. Because the signal has approximately twice as many scan lines as a conventional system, those lines are not visible at HDTV -16:9)t.77:11 distances as close as three times the image height. r 1 1 ü Another factor adding to the impres- station that does a conventional one, thus Sion of realism offered by HI)T\' is a requiring a bandwidth at least five times NTSC change in aspect ratio. the ratio of an greater than that specified for the NTSC 4:3 image's width to its height. Conventional system used by U.S. broadcasters today. (1.33:1) TV has a 4:3 aspect ratio, which means I'h:t translates to a bandwidth require- that the picture is four units vide and three ment of 3)) (\1 Hi. compared to the (t MHz units high. That aspect ratio was adopted NTS( standard. originally to conform to what vas used at To squeeze all of the information re- FIG. 2-ASPECT RATIOS. Here, the aspect the time foi motion -picture photography. quired for a h-II).1\' picture into a more ratios of conventional -TV, HDTV and Panavi- Iltese days, most films are shot using the manageable bandwidth. NI -1K developed sion motion -picture viewing screens are com- P:utayision process. which uses a I.85:1 a system called \1USE (A1('Itiple Sub- pared. (5.55:3) aspect rttio. It is expected that Nyquist ,Sampling Encoding). MUSE HDTV will use an aspect ratio bet\wen converts a wide hand analog studio signal the two. with 1.77:1116:9) being endorsed to digital form. compressing it to slightly

f i by many. See Fig. 2. more than f; NI Hi for transmission. At the i receiver. the signal is re -expanded to its The NHK system original form for displa'. the \111SE As we mentioned earlier. the 11D TV specifications call for: system closest to being a practical reality / e

I 0 ; is the one proposed by Japan's N I K . I Ica Processing of luminance and rhronti- ; * system uses a signal with 1125 scan lines n:rnce information by TCI (Tinte Com- and a 2:1 interlaced scan rate of 6(1 fields pressed /ntcgtition). $-1-(;) (30 frames) per second. NI IK's HMV Finic-compressed line-seq le itial pro- U I b I i I O system has already been demonstrated cessing of chronrinance information gen- SUBSAMPLING POINTS: both in Japan and in the U.S. etating R -Y (red minus luminance) and 1st FIELD One problem with all I IIYI'\'systems is l3- Y (blue minus luminance) color-dif- o 3rd FIELD that they potentially require enormous ference signals. o 2nd FIELD 4th FIELD amounts of bandwidth. For instance. in Tinre compression of the chronlinance FIG. 3-THE SAMPLING PATTERN used by the system proposed by NI IK. a high- signal by a factor of four. NHK's MUSE system. Picture information is delinil ion T\ picture contains about live li:utdv. idth reduction of the TCI signal trarsmttted over four fields rather than the two times more luminance (brightness) inior- throueh subsampling. of conventional TV.

49 Illg reconstruction t1s111g t\\o or more tional Radio Consultative C'ommittee's signal that is derived from an HI)T\' sig- fields will yield a picture with unaccepta- l986 Plenary Assembly. Instead. a deci- nal of 1(150 lines. The second channel ble blurring. 'That's because the picture sion \\ as postponed until Io)o)(I. at the ear- contains the high -frequency luminance content will he changing from field to liest. That postponement has added some and color -difference infittntation. Ac- field. Therelitre. only the inlormation confusion to the HDTV world. so there is cording to Bell Labs. a normal NTSC front one held can he used to form the no guarantee as to what shape. if any. a receiver \\ould receive the NTSC channel image and a I:4 kiss of resolution occurs. world\\ ide specification will take. It is with only a slight degradation of picture Hoy. ever. a MUST: receiver also incor- expected. however, that the II25/60/2:1 quality. An HDTV receiver would receive porates a motion detector. That stage en- standard will become a de /lido standard both channels and combine than using a ables the receiver to integrate the in most 60 -Hz HDTV studios. frame store. the result is then scan-con- stationary and mo\ ing parts of a scene Several of the systems are of the MAC verted to reproduce the original 1050 -line into a single image. (That's where the (Multiplexed Analog Components) type. picture. ..motion -compensated" part of the In a MAC signal. the luminance. color C'13S has proposed another Iwo -channel MUST: system conies in.) The result is difference. and multiple digital sound sig- system. One channel would contain a that stationary parts have maximum reso- nals are compressed in time and multi- MAC -like time -multiplexed component lution while moving parts appear slightly plexed onto the same signal. In particular. signal in a 525-line/60-11z format. The blurred. Such blurring is not considered most European HDTV systems are based second Channel would contain another serious. however, since our perception of on some type of MAC system. time -multiplexed component signal. sharpness is not reduced by blur in a mov- For instance. Philips, the Dutch elec- When the t\\o signals are combined. an ing image. We simply accept it as an at- tronics giant. has proposed a European HDTV image results. The system does tribute of the motion. IIDTV system called HI) -MAC. The sys- not require a receiver \\ ith frame store and A special case in the \1USF. system tent is based on the 625 -line. 50-11/ PAL v, mild use Direct-Hroadcast Satellite occurs \\ hen the camera is panned or standard. The input signal is 1250 lines. (Dl3S) deli\ery. tilted. causing the entire image to change. 50117. \\ ith 2:1 interlace. Vertical littering William Glenn of the Ne\\ York In- When the encoding circuitry detects that is used to make a wide -band \\ idth stitute of Technology has proposed a sys- ty pe of picture content. a vector represent- 625/50/2:1 signal fir transmission. The tem that snakes use of the properties of ing the motion of a scene is eaten kited and bandwidth is reduced by transmitting human vision to reduce the bando idth of the inlitrntalion is sent during the vertical - only alternating horizontal samples: lour a transmitted HDTV signal. In his pro- blanking inter\ al. At the receiver. the in- fields are required to receive a complete posal. an "improved" NTSC signal is iirmation is applied to the field memo- HD -MAC picture. That. once again of transmitted over a standard NTSC chan- ries. causing the position of the sampled course. means that the receiver must have nel. (Those improvements could entail picture elements to he shifted as appropri- a frame ritetitory to display the pre -combing to eliminate interference be- ate to the motion. The bottom line is that 1250/50/2:1 picture. tween the luminance and color informa- the mowing pictures are processed as if Other MAC systems are similar. except tion. use of progressive rather than they \\ ere stationary ones. \\ ith conspic- 1hr the numbers involved. For instance. interleaved scan. etc. Some improve- uous blur in unitarntty moving regions of B -MAC is a MAC system that's compati- ments may require nxtditied NTSC re- the image held to a minimum. subject to ble with tite I125/60/2:1 proposed world- ceiving equipment.) That signal. which the accuracy of the motion \ectors. Note wide standard. already \\ ill offer somewhat better resolu- however that non -uniform moving regions And things have not been quiet in this tion than standard NTSC. is accompanied will unavoidably suffer a loss of resolu- country. either. Bell laboratories has pro- by a 3 -MHz \\ ide auxiliary signal that tion. In most instances, however. such posed a t\\o-channel transmission system contains high -frequency, low temporal - loss will he acceptable as a consequence in \\ hich one channel contains an NTSC rate information. as well as intitrntation of motion.

Other systems Although NHK's MUSE. system is the NTSC NTSC one closest to implementation. work on PIXEL PIXEL HDTV is also continuing in Europe and NTSC l EVEN FIELD the U.S. In this section \\e will look at PIXEL SCAN LINE some of the more promising systems. lJ! Most of these systems are based on the ODD FIELD J/ SCAN LINE billowing standard: 1125 lines. 6(1 frames per second, 2:1 interlace. 16» aspect A E C A E

ratio. The number of lines \\ as chosen as a C A E C

compromise between the PA L/SECA M B F D B and the NTSC camps. It is more than I0))0 D B D lines. but not exactly equal to twice either 625 or 525 lines. Also, although 50 A E C A E frames per second is used in Europe and C A E C elseo. here. the NTSC standard of 6(1 frames per second was accepted because it substantially reduces flicker and allo\\s a higher sampling rate. Interlaced scan- SAMPLE TRANSMISSION: ning. as opposed to a progressive scan- x=1/1300 PICTURE WIDTH A=6nth FIELD D=(6n+3Ph FIELD scheme. is used because of the ning B=16n+1Ph FIELD E=I6n+4)Ih FIELD reduced band \\ idth it requires. y=1/1000 PICTURE HEIGHT C=(6n+2Ph FIELD F=I6n+5Ph FIELD Note that those specifications have not been han 1tally accepted as a worldwide standard. ho\\ever. It was hoped that a FIG. 4-IN THE DEL RAY HDTV SYSTEM, each NTSC pixel is broken up into six samples for transmis- standard \\ould he adopted at the Interna- sion. Picture information is relayed in a sequence of six fields.

50 required to produce a w ide aspect -ratio i :n:no-up tem in which an NTSC receiver could be picture. The two signals would he com- modified. perhaps through an Outboard bined in a frame store to produce an adapter. to receive III)TV signals. Of IIDIN image. course. the cost of such a moditication The Del Ray Group of Marina I)el Ray. must he relativelvlow to he practical. If it CA. has proposed a system that uses a is too high. most consumers would opt to single NTSC channel to transmit a forgo modification and simply replace 52516012:I HDTV signal. They propose a their et uipment when they decide to up- systems in which a single NTSC lumi- grade. A final possibility would he that an

nance sample (pi se I I is broken up into 6 NTSC receiver simply could not he used samples. One sample is transmitted each to receive and display 111)TV signals in field until alter 6 fields the complete anv firm. In other words. it would he a NTSC pixel is sent. The sampling pattern completely incompatible system. is short n in Fig. 4. At the receiten. a frame Of course. compatihility is a desirable store is used to recreate the complete pic- . . 1 -- goal. but y.ou can not overlook the cost at ture. According to the Del Ray Group. FIG. 5-AN HDTV videotape recorder from Sony which it is achieved. At this point in such a signal could he displayed on a non - was used this past spring to present one de- HDTV research. it appears that the higher signer's spring line in New York. I DTV NTSC receiver st ith little degrada- the compatihility with existing systems. tion when compared with a normal NTSC the poorer the high -definition perfor- signal. mance. Images still he strikingly better A wider aspect ratio is achieved in this on 13 GHi, I -M was used. In general. the than those provided by a non-HI)I'V sys- systems by reducing the number of active results sere satisfactory.. although some tem. but they will not provide maximum video lines transmitted by 69. The Del problems sere encountered with the PCM possible performance. Ray Group contends that due to otcrscan digital audio, which was designed tie sat- On the other hand. the highest perfor- losses in a typical receiver. the returned ellite rather than terrestrial distribution. mance HDTV systems will likely he lines would not he missed. Further. those when the signal was attenuated. That achieved only if the compatibility prob- 69 lines could then he used to transmit problem sill have to he solved to make lem is completely ignored. In that event. a digital sound. terrestrial distribution of a MUSE signal separate programming distribution sys- practical. tem likely will develop that will supply Distribution Ile other way in which HDTV pro- prop -rimming to v levers that possess the Alter an HI)T\, spccilication has been gramming could he provided is in pre- appropriate equipment. established and agreed upon. the problem recorded form on videotape and vid- Ignoring compatibility altogether is not remains of how to distribute material pro- eodiscs. While the wide handyy idths of Without precedent. When FM radio duced in that medium to the public wait- HDTV are beyond the capabilities of con- broadcasting was introduced. that mode ing for it. So specifications. distribution. ventional broadcast and consumer equip- was incompatible w ith the existing AM and compatibility are 111)1V's toughest ment. Sony and other manufacturers have system. 'Ilrt. however. did not stop peo- remaining problems. Let's look at the dis- developed systems capable of storing ple from investing in what then was ex- tribution problem in more detail first: later HDTV images. See Fig. 5. pensisc equipment to take full advantage on we'll delve deeper into compatibility. of the benefits (superior audio quality) As with Coda s's y ideo programming, Compatibility offered by that medium. there are two alternatives: broadcast and High -definition television is certainly I he fewer FM system coexisted st ith pre-recorded material. In the realm of practical. Indeed, it already exists. The the older AM one. and prospered. 'loduir. broadcasting. one possibility is, of problem that concerns many. though. is it is commonplace to find AM and FM course. DRS. Satellites could provide a host to get program material produced in tuners in the same piece of equipment- distribution route completely independent that medium to the greatest number of even small portable receivers. And even of those used for conventional broadcast- viewers. now the same program material is some- ing. and the compatibility issue could, in In the past. virtually all improvements times broadcast by a station in hoth AM a sense. he skirted. It has been suggested in broadcasting in the U.S. have been ano FM. so that those tv ith FM equipment that the most economical and practical achieved within the framework of the sys- can enjoy the all the benefits of the nest system for distributing HDTV is h 1)13S tem established in the 1940's by the technology, and those who are still AM - in the 22- and 40 -Gilt hands. (For more NTSC: other TV systems have also main- hound will not he left out. on HDTV and I)RS. see Satellite 'I'V tained compatibility with existing equip- Similarly. television broadcasters could elsewhere in this issue, as well as in the ment as they were improved. Although provide high -quality HDTV program- July issue of Radio -Electronics.) newer receiving equipment has been re- ming by satellite or some other means to Until recently. most observers had quired to take full advantage of improve- those equipped to receive it. while per- ruled out terrestrial broadcasting as a pos- ments such as color and stereophonic limning scan- and media -conversion at sible distribution medium. However in a broadcasts, program material incorporat- their awn facilities and simultaneously test conducted this past January in the ing those improvements has generally. sending NTSC-format signals containing Washington. I)C area by the NA13 (Na- been able to he received and enjoyed using the same arterial on their conventional tional Association of Broadcasters) and equipment already in use. VHI- and UHF frequencies for v icwcrs the MST (Association of Maximum Ser- The ideal, of course, is to develop a with existing NTSC (or P\I. or SECAM) vice Telecasters). two adjacent UHF system in which a current receiver could receivers. channel slots were used to transmit a accept an HDTV transmission and display Whatever final form politics. policies, MUSE HDTV signal. At the same time, a it in HDTV form. In all likelihood, that is ar,d technology dictate for HDTV, it ap- I3-GH, terrestrial-microsase relay signal an unattainable dream. More likely would pears that there's no holding that tech- was used as a backup, and to demonstrate he a system in which an NTSC receiver nology hack. In just a test short years. the feasibility of using that hand in areas would he able to receive an HDTV signal Japanese viewers s ill he enjoying its ben- where sufficient UHF spectrum sass un- and display it with the same or slightly efits: it's yen likely that shortly thereafter available. On the UHF band the broadcast worse quality as it displays an NTSC sig- well he getting the "big picture" in this vas made using vestigial sidehand AM: nal. Another possibility would he a sys- county . too! R -E

51 rA\ -Lf\A

I...I... its let I I..,\ltl.'i 11.,\It1 ell. tierI.II)- state equipment design. the FCC's exam- CERTIFICATION ination li,r a /sí (7oss (;enertii kuflin- telephone Licensee yvhich is almost universally kno»n as a "First -Phone... covered most of what there was to know FOR about the electronics of communications. Except tir' radar. which was an endorsement on the license obtained through a separate examination. the knowledge needed to eel a First -Phone was so broad and so thorough that the license was often a prerequisite for general technical em- tQztrvnic$ ploy ment. even though the license was 1M...rq intended only for technicians whose job insolsed transmitter adjustments. The reason why employers placed so Dale offa,up. Reqnf,alan No.:

much faith in the First -Phone was because Decembn, 1985 CA15BD it certified a minimum level of knowledge and skill. I:sen it the job open was repair- he it blownlint ing home stereo receivers. an employer three presents that he that someone could reasonably ceitain 1.. Wiley_ C. _~f _SIT - ,,, . with a First -Phone had an acceptable un- n,. ,..cuuf.aly c.n.Vend :be Te..finiul Ten. and R ..rvem.00 aeúw.mr.eo,l ..rnv.mon ¡ 1114'1'1'1 of both electronics and elec- for comp..... abbey and kooMedge es Certified Electronics Techn.ian. s boomeyrnan of derstanding 1M trade tric fundamentals. T1Na oenM'ba n Issued lnm.ry by But suddenly. almost overnight. the general radiotelephone license lost holh value its need. First. as with all its and .,.._.... V ...... ,, other things. electronics technology became so complex and sophisticated that no one could he espected to he e\peit, or moss* x even merely competent. in more than one or two specialized areas of interest. Be- cause the radio broadcasting services no longer represented a major area of elec- ELECTRONICS tronics. having a license that certified competence with transmitters and antennas no Ioncer implied competence with the mainstream of electronics equipment. TECHNICIANS Second. their was something called ..license deregulation." Modern technology had made the stability of radio If you really have specialized knowledge and skills- equipment so reliable that as far as the if you know your can become a FCC ysas concerned. other than for the stuff-you ship and aircraft services there was really certified electronics technician. no longer a need for a specially -licensed technician. So the FCC eliminated the requirement that only an FCC -licensed W. CLEM SMALL, CET technician could slake adjustments and repairs lo transmitters: It hecante the re- For the seasoned technician. past em- shops can aflirrd Io spend. One effective sponsibility of the owners and operators ployment records may be all the recom- \\ ay to ensure the proper testing and eval- of radio -transmitting equipment to ensure mendation that's needed. but firr the less uation of potential employees is to use the proper operation. (Although Congress experienced person it is usually a different certification procedures of the various implied that the RA' could recognize and more complex situation. While it is professional organizations that have technician "certification- by industry - possible for an employer to ask for tran- estived to serve the communications and sponsored private organizations-and scripts of the applicant's trade -school electronics industry. In fact. within the that agency has sent out notices about training. many new technicians who want broadcast and telecommunications indus- programs available-it officially recog- to work in communications have picked try, most emplo\ers who filrtnerlv re- nizes no ''private- certification of any Lip their knowledge without going io a quired the FCC First -Phone now require kind.) formal trade school: How are they to es- for accept) certification by a professional Since an FCC license no longer re- tablish their knowledge and competence? or industry -sponsored organization. Ilected the major interests of electronics. The e'act procedure used for the cer- and since very few positions in the com- Certifications tification of technicians depends on the munications industry required an FCC li- Often. employers will test job appli- particular organization. For esample. one cense. how. then, was an employer to cants. but if properly done. on -site testing early approach was to consider a techni- evaluate a potential employee's technical can be a relatively expensive undertaking cian's pas( FCC license level and perhaps knowledge and skill? that often costs more than elan, small his employment under that license. Both

52 tificati in requires a combination of ad- , L. NStaI`. 1 vanced schooling and extensive experi- YEREu.LL / 1 j1 (]y i `j{`¡I For example. their Ir woest class of LÍ'i %T>Je.?).f71:+'I `f 2 i}jr.Y}T7i ,i-J2-27, ence. engineering certification require, either a fEDE$ALYCOMIIIINICATIONS CO1IIISSIONI© two- or lour -year engineering degree. or lidkl ffiJ91inclfflliQ«11111111r11"11,Icll[~, previous high-level technical certification FIRST CLASS plus two years of engineer-Iesel experi- I I R.elotelePhona CotlflGatel ence. The NAR F.'s minimum technician .%/li ii7/0iY .r/ WILEY CLEDION SMALL certih eat ion (Class I\'I requires an examination. while the highest (Class II re- M 5' 101/21 190 coBlue. I Rad-erown 11-27-I2 quires pre\ ions cenificalion plus six years 15 A LICENSED .010 OPERATOR. AUTHORItto. SUBJECT TO 1.e SPECIAL 91.00RsH.T PLACID .E ON. TO °.IRATE 'Pt CLASSES Or LICENSED RADIO 51.1101.5 row WHICH .15 CLASS Or LICENSE IS VALID UNDER 11.E ORDERS, RULES AND REGULATIONS Or 11.E FIDIRAI verifiable radio or telecommunications CDa NUbICA110N5 COan5S10N..1 STATUTE OF 11.E UNITED 51Alr5 ND NY TR." TO emu< rat UNITE° sTAtIs IS A PART. THIS IICl NS1 Is GRANTED UNDER THE AUTHORITY OF THE CONNUNICATIONS ACt Of TRa. AS ..DELI. AND THE TEI.5 ANO CONDITIONS experic mice. THEREOF .1.° or ALL LEGISLATIVE ACTS. EAKUOVE ORDERS. NO TREATIES To HHIC. rat UNIT. ST... SIGNATORY, .0 ALL ORDERS RULES AND REGULTONs Or THE FEDERO. COYNUNICALONS CON .15510N, WHICH ARE BINDING UPON RADIO ORATORS. ARE RDE LIT HEREOF .5 THOUGH 5ECIFICALLY SO OUT IM FuLy HERON, THIS NOR t RIGHTS TO HERON SHALL Br ASSIGNED OR OrMUwISE TRANSFERRED TO A. NIKON LICENSE Olt CERIIOrO 0.. CET

PLACE OD oT1 of 11:uNCI San Francisco, California February 22 1978 Loiig helore FCC deregulation. elec- February recognised the need DA If ND Oat Or E. PIR110N 22, 1983 Too O'CLOCe A esttRH sTHoRo tat tronics professionals for certify ing electronics technicians in SPEC I Al 9.1.0' LOSES PeT troubleshooting consumer products. in basic logic circuits and industrial con- EXPIRED r edee.t 1'nmmUnrr old on trols. and the safety and accuracy of cal- E'.mmd.atnn letv4 pnr ibration for medical electronic instruments. As early as l965. the WI. test ;,d ,k' Cau-ti &--e< used by the /nternational Society of Cer- NOT VALID UNTIL SIGNED tified Electronics Technicians IISCl f) X ti;a';` X. {ti..., used exams than tested hlack and white THIS WAS THE LEGENDARY First -Phone FCC license. No longer in existence. it attested to the telex ision adjustments. audio speaker en- holder's general technical competence. It was often a "ticket to success" in communications. closures and adjustments. and the use of electronics test equipment. Nearly k i MAMg mg , 20-(1110 technicians had passed those i Ti - i17 1l'' ' i' }'` exams (out of about 70.0110) esen before %i/iaiiiii/iniin/ i/ili'üA/y of the FCC deregulation. Persons passing -,F the appropriate tests may first attain the r(iAi/í`iiv/ j10i'/iniiül.1 .%i'/liü'iniia apprentice electronics -technician certificate. and then one or more advanced jour- REGISTERED RADIOTELEPHONE OPERATOR LICENSE neynian-level certificates. (General Rahorelepnone Certiticatel

This cernlm that the individual named and described below Is a licensed ran. oprr.tor and H authorized to operate licensed tad!, stations lot which this class of license Is valid The authority granted Is wb,ect to any endorsement placed on TN s license The .a thoo granted n also subject to the orders. rules, aano c reguletions of the International CERTIFICATION PROGRAMS Society o1 Certified Electronics Techn,ansc, and the statutes of the United States

The license may not be assigned or transferred to any other person. It e.poes at tetes o'clock AM Eastern Standard Tome on the date shown below Electronic's Technicians Association 604 N. Jackson St.

1Hrnve SAMPI` Greencastle, IN 46135 International Society of Hair Sea HeegrI weight Color Eyes Color Date of Roth Certified Electronics Technicians 2708 West Berry St. 'lace of Issuance E.pnation Date License Number Fort Worth, TX 76109 r Aftem National Association of Business and e3riiiti_ ' Educational Radio mvnvrRr. Nl .eHorr ,or lone NNnnut /SCFT Go, P.O. Box 19164 20036 1 :. ' L Washington, DC 4J' i ftii?h ll J 9154N,~~_rX National Association of Radio and SEVERAL PRIVATE CERTIFICATES are similar in appearance or format to the old FCC First -Phone Telecommunications Engineers license. PO. Box 15029 Salem, OR 97309 the National Association of Business And technologies such as cellular telephone.

Educational Radio (NA B R ) and the So- as well as the telecommunications skills National Institute for Certification in ciety of Broadcast Engineers ISBE) have needed since the breakup (deregulation) Engineering Technologies had certification programs that required of AT&T. requires highly special:zed 1420 King St. Alexandria, VA 22314 prior possession of an FCC license as a knowledge. which is certified Ihr"uch basic requirement. Upon satisfaction of special exams given by the National Asso- Society of Broadcast Engineers a re- Radio And Telecommunication their requirements. certificate that ciation of P.O. Box 50844 senthles the old FCC license is awarded to /engineers INARTIi1. which eenifie; on Indianapolis, IN 46250 the applicant. On the other hand- various two level,: technician and engineer. Al- aspects of existing and emerging radio most without exception. NAKTI: cer-

53 Two orr auiixalions that oiler a CET or ('.I:.'I'. testing program arc ISCL f and the LIertronic Technician's Association FIED TECH 11 ::FA f. Options that are available from one or the other of these programs include CI most major areas within electronics technology. G Within the ETA program are the advanced options of Senior (.1:.1' and Mus- The National Association of ter ULT. ss hich are available to persons Business-` and Educational Radio, Inc. with eight or more years of experience in Certifies that the profession. Higher passing scores in a chosen option are required for the senior rlr; ill; Tiernan Intuit level than for the lower levels. fhe master has demonstrated a knowledge of option requires passing an examination the Federal Communications Commission's Rules and Regulations governing the Land Mobile and Private Fixed Radio Services and has shown a general comprehension that co\ers consumer electronics. coni- of the theories of electronics and radio propagation. This individual is hereby recognized as a SABER miercial electronics. communications. in- Certified Technician through a FEDERAL COMS111NICATIONS COS1S11SSION endorsed program. dustrial elect ronics. computers. and bio- medical electronics. IS('I f has two levels of cenification. ¡9G4, (,(11,4," £14a! Associate CET's must pass an want cover- PRESIDENT. Ni8a3t / SIGNA UREOFTECIiNICIAN ing basic electronics. circuits. semiconductors. test instruments. and basic AUGUST 1. 1984 AUGUST 31, 1989 DATE OF ISSUANCE DATE OF EXPIRATION troubleshooting. Technicians with liaur years experience can take the higher -level 17540 - .h ------a1 Purnevnunl exam at the same time. They --- must he cenilied at the Journeyman level EVEN WHEN THEY DON'T RESEMBLE the First -Phone license, some private certificates such as this one state or imply endorsement by the FCC, the FCC not use although does approve. sanction, or to CET after their names. ('ET's are endorse any private program. issued permanent certificates suitable liar framing and a plastic wallet card. Once certified as a C'FT or C.E.L. technicians are eligible tin membership in the parent organization. ISCEr or ETA. vtemhers receive hooks. magazines. re- International Society of prints. and regular technical material: may attend conventions and technical Certified Electronics Technicians training programs: and receive discounts on hooks. tapes. and software. Rut the Associate Certified Electronics Technician real henefit of certification is a growing awareness within the electronics industry Ep anon Date that a certified technician is a person who Regiseauon No has demonstrated considerable skill. understanding. and competence in his or her tested areas. be it known br these presents that The FCC CET and s-ia aYr. c -:r The l('(' has made no official sanction tras ssIuny completed The technical tests and Redunemems geeing u ersal recogna!on to, of any private -industry cenification pro- abilay and knowledge as an AssoateAssoc-ate Certified Electronics Technician gram. Public notices have been issued by tres Certificate rs issued piney by the F('(' to assist technicians in locating . . certification programs. but those have 12/ e 7 specifically stated. 'The Commission ófrar.' L« vt( 4t:ou. does nil approve. endorse. or officially sanction any private sector cenification program...- I-lossever. in its Repon and Order. docket 83-322. 49 Fed. Reg. 20o55. the Commission did endorse the PRIVATE -SECTOR CERTIFICATION attesting to a minimum level of knowledge and skill is available concern of private sector ceni neat ion pro- for various areas of electronics. It often serves as a"ticket to success." grams as a possible substitute tiny Com- mission testing of commercial radio nixed by employers is worthless. If you For more intiarmation on how to get operators. want a particular kind of job. say in cel- certified in various electronic tech- lular phone. or even broadcasting. check nologies. you should contact the major The right certification with some large operations and specifical- private certification organizations listed in It is reasonable to expect that, as more ly ask if they recognize or require private the box that can he hound elsewhere in this and more jobs require certification of cenification or licensing and, if So. from article. Although those organizations are some kind ni lieu ()I' the old First -Phone. whom. If you choose to work in an area not -for-profit. they do have a reasonable sse're hound to see a plethora of private that requires pri vale cenification. hear in tee for testing and processing. In Par- organizations offering their own version mind that as a general rule the higher the ticular, we suggest you enquire as to what of private licensing. Rear in mind that certificate for which You qualify. the study guides they specifically recom- cenification that isn't specifically recog- greater the potential job opportunities. mend. R -E

54 TRA NSIS TOR

WI WIiRI: HAVING TROUBLE FINDING AN exact replacement transistor while repairing a piece of equipment recently. Figur- ing that an eruct replacement was going to he impossible to find, we began to discuss what to do. And someone pointed out that there were only two kinds of bipolar transistors-NPN and PNI'. Of course. values for various characteristics vary widely. even for a specific transistor: but in maiiv circuits. a garden-variety device will work (and did in our case). Designing and repairing transistorized circuits is much simpler than you might suspect. A well -designed circuit hasbuilt - in tolerance. so it's probably not device - sensitive. The most important characteristics to consider when substituting devices or designing a circuit front scratch are operating frequency and power level. What follows is the design procedure we went through to solve an audio -gain problem. Try it when you need a little extra gain for that next audio project.

An audio amp Ibis particular project involved inject- ing the audio from a TV receiver into a stereo system. the audio -output portion of the 1 V -audio receiver was abandoned because of its poor frequency response and high distortion. Instead. we wanted to come right off the detector into a quality audio amplifier and speaker. So. after picking off the audio at a convenient point in the set (in this case. from a potentiometer). we wanted to feed it to the auxiliary PLIFIER input of the stereo amplifier. The amplifier we used required an input of I volt rms. hut a quick check with an AC VTVM indicated that our picked -off DESIGN audio signal was only 0.1 -volt rms. Ob- JACK CUNKELMAN viously, an amplifier with a gain of 10 was needed. It's easy to design a simple transistor amplifier. Here's how. Scanning the literature on transistor annplitiers revealed that a common -emit- The power -dissipation rating of the thumb." We will learn how to make the ter amplifier with a voltage -divider bias transistor must not be exceeded. calculations next. circuit would solve our problem nicely. the beta of the transistor should he 1(K) Such a circuit is shown in Fig. I. Sorne of or higher. Doing the math that circuit's characteristics include: mod- In our example the follovk ing facts are For max inform undistorted output erate input impedance. moderate voltage known: swing, we will make the quiescent collec- gain. inverted output. and input/output Our amplifier had a single -ended 12 - tor voltage % the supply voltage. See Fig. impedance and gain that depend only volt power supply. 2. The drop across ke must therefore he 6 slightly on transistor beta. We need a voltage gain of 10. volts. "There are. of course. several rules that The input impedance of the amplifier The value of Re. the collector load re- must he followed in using a common - should he about 15K. the same as the sistance. is chosen considering output im- emitter amplifier. including: potentiometer front which audio was pedance. gain. and collector current. II With a positive supply use an NPN taken. possible. the output impedance should he trnsistor. The impedance of the stereo amplifier's lower than the impedance of the circuit we With a negative supply use a PNP tran- auxiliary input is about 50K. are feeding by a factor of 10 or more. sistor. As is the case in most circuit designs, a Doing so will avoid circuit loading. So the supply voltage must not exceed the few facts are known. and the rest must he let's make Rc equal to 47(K) ohms. which transistors V(.I. rating. calculated or picked using a few "rules of is about 50K/10.

55 LISTING 1

10 CLS TO THIS IS";R1 20 REM TRANSISTOR AMPLIFIER CALCULATIONS 360 PRINT "CALCULATION OF THE INPUT AND 30 REM BY JACK CUNKELMAN OUTPUT CAPACITOR VALUES" 40 REM APRIL 1986 370 INPUT "LOWEST FREQUENCY THIS AMP SHO 50 GOSUB 900 ULD PASS";F 60 INPUT "SUPPLY VOLTAGE";V 380 Cl = 1/(3.2*F*IZ) 70 PRINT "THE DROP ACROSS THE COLLECTOR 390 Cl = Cl * 1E+6 RESISTOR ="V/2"VOLTS" 400 C2 = 1/(3.2*20*Z) 8): INPUT "INPUT IMPEDANCE OF THE FOLLOWI 405 C2 = C2 * 1E+6

NG STAGE(OHMS)";Z 410 IE = VE/RE : RJ = .03/IE 90 RC = Z/10 420 A = RC/RJ 100 PRINT "COLLECTOR RESISTOR. RC SHOULD 430 C3 = 1/(6.2*F*RJ) BE"RC"OHMS" 440 C3 = C3 * 1E+6 105 INPUT "THE CLOSEST 5% RESISTOR VALUE 500 CLS TO THIS IS";RC 510 PRINT "PARAMETERS FOR A COMMON EMITT 110 IC = (.5*V)/RC ER AMPLIFIER STAGE" 120 PRINT "THE COLLECTOR CURRENT IS"IC * 520 PRINT 1000"MA" 530 PRINT "SUPPLY VOLTAGE 130 INPUT "DESIRED VOLTAGE GAIN";G ."V"VOLTS" 140 RE = RC /G :R$ = CHR$(32) 540 PRINT "COLLECTOR RESISTOR (RC) 150 PRINT "THE EMITTER RESISTOR FOR THIS ."RC"OHMS" GAIN IS"RE"OHMS" 550 PRINT "EMITTER RESISTOR (RE) 160 IF RE<=39 OR RE =>1001 THEN 170 ELSE ."RE"OHMS "Re 180 560 PRINT "BIAS RESISTOR (R1) 170 R$ = CHR$(42) ."R1"OHMS" 180 INPUT "GERMANIUM (G) OR SILICONE (S) 570 PRINT "BIAS RESISTOR (R2) TRANSISTOR TYPE";T$ ."R2"OHMS" 190 IF T$ ="G" THEN 210 580 PRINT "INPUT CAPACITOR (C1) 200 IF T$ ="S" THEN 220 ELSE 180 ."C1"MF" 210 J = .2 :GOTO 230 590 PRINT "OUTPUT CAPACITOR (C2) 220 J = .6 ."C2"MF" 230 VE = IC * RE 600 PRINT "VOLTAGE GAIN 240 PRINT "THE DROP ACROSS THE EMITTER R "6 ESISTOR IS"VE"VOLTS" 610 PRINT "TRANSISTOR BETA 250 VB = VE + J "B 260 PRINT "THE BASE VOLTAGE MUST BE"VB"V 620 PRINT "LOW FREQUENCY LIMIT OLTS" ."F"HZ" 270 INPUT "WHAT IS THE DESIRED INPUT IMP 630 PRINT "EMITTER BYPASS = "C3"MF FOR A EDANCE FOR THIS STAGE";IZ GAIN OF ...."A 280 R2 = IZ*RE*100/((RE*100)-IZ) 700 INPUT "RUN AGAIN..Y OR N";R$ 290 PRINT "THE BIAS RESISTOR, R2 IS"R2"0 710 IF R$ ="Y" THEN 10 HMS" 720 IF R$ ="N" THEN END ELSE 700 300 INPUT "THE CLOSEST 5. RESISTOR VALUE 900 PRINT "CALCULATIONS FOR A COMMON EMI TO THIS IS";R2 TTER AMPLIFIER STAGE"

310 VD = V - VB : I2 = VB / R'2 910 PRINT 320 IB = IC/B 1000 INPUT "TRANSISTOR BETA IF KNOWN (0 330 R1 = (V - VB)/(IB + I2) IF UNKNOWN)";B 340 PRINT "THE BIAS RESISTOR, R1 IS"R1"0 1010 IF B = 0 THEN B = 100 HMS" 1020 RETURN 350 INPUT "THE CLOSEST 5% RESISTOR VALUE

Collector current. li.. is equal to 0.5 The voltage drop across the emitter re- ZIN = (R2 x RE x b)/[R2 4 (Re x ]3)] V(./R1.. or 6/47011 = I.28 mA. That sistor = I( x RI;. or 1.28 mA x 470 current is certainly low enough that we ohms = 0.602 volts. The base voltage R2 = (ZIN x RE x P)/[(RE x11) - ZIN] Will not exceed any collector-current rat- must exceed the emitter voltage by 0.6 R2 = (15000 x 470 x 100)/[(470 x 100) ings, so let's go on. volts for a silicon transistor and by 0.2 - 15000] To achieve maximum stability. the volts 1. r a germanium transistor. W'e'll R2 = 22,030 ohms emitter resistor should he in the range of use a silicon transistor in our circuit. so 4(1 to 1011(1 ohms. Voltage gain (Ay) = the base voltage must he 0.6 + 0.602 = We can use a 22K resistor. In general. if R(./R,,, so RI:, = R(./Av In our case Rr. 1.202 volts. input impedance is not critical, for max- equals 4700/I0. or 470 ohms. That falls The input impedance of the circuit imum stability R2 can he 10 to 20 times within the range of acceptable values. equals R2 in parallel with the emitter re- Rg. l'he current through the emitter resistor sistor times beta: input impedance will The drop across R2 must he 120 volts. consists of the collector current plus the vary with the transistor's beta. For our so the current through R2 is 120/22.111111,

base current. The base current here is sig- example. assume k1e are using a transistor or 0.054 mA. Therefore. R 1 must drop the nificantly smaller than the collector cur- with a beta of 100. We want the input rest of the supply voltage. Which is 12 - rent. so it can he ignored fin- the next impedance to he about 15(10(1 ohms. Solv- 120 = 10.8 volts. The current flowing calculation. ing for R2, we find: continued on pore 77

56 L_.

The robot's command language

NOV, THAT WE'VU. S- NM: can combine a sequence of com- RCL basics Part 9 semhled the robot's mands and store them for execution ar a The software that controls the robot is hardware. it's time to dig into the soft- later tinte. In addition. commands can built up layer by layer. 'lie most primitive ware. In this article we'll describe the R -E also he executed immediately from the olds must he defined first: more -com- Robot's command language. RCL keyboard. plex words are defined using the pre- (Robotic Control Language). It's an easy - viously defined words; at the top level are to -learn and easy -to -use language written Real-time control the RCI, words that stake motion control in I-'OR'I'I-l. I)on't he scared by FORTH: Ilse R -E Robot consists of a coniputer- easy. As each word is defined it can he you can use RCL without being an expert controlled set of electromechanical de- tested and debugged. When it is debug - at progranuning in the language. And. as vices. "Ilse assembly is broadly known as a gee. the next layer may he defined. you learn RCL. you'll learn (painlessly) 'notion -control .cVstc iti. Notice that you are defining words. the basics of how FORTH works. so that. Real-time motion control requires real- rather than writing a program. as with if you ant to. you can go on and learn the time sensing and processing. One way to mast computer languages. That's not just language itself To give you a chance to ensure proper sensing and processing is to a matter of semantics: it's also a way of see RCI. in action. we'll present a robot - force the computer to execute a control looking at a programming problem. The based mail -delivery system. You can loop at regular intervals. lbat control loop problem can he broken down into a series study our program to learn how RCI. will he the computer's highest priority'. of smaller problems, and then those prob- works. and you can also use it as the basis Ex cry thing else the computer does will he lems can he broken down further. and so of your own program. second". and it will have to do those on. until you have a set of problems that How difficult is RCL? Not very. For other things as it finds time. can he programmed. Each little problem example. suppose you wanted the robot to A simple way to implement the control becomes a FORTH word. which in tiirn stove in the Inward direction 3.4 feet at a loop is to have a clock IC generate an becomes pawl of another FORTH word, so speed of 2 miles per hour. You ould interrupt at regular intervals. Each time that eventually all we have to do is say simply type in the Billowing code: the clock interrupts the microprocessor. it so nething like will execute the control loop. and then it RERB 2 MPH 3.4 FEET FORWARD TURN -LEFT will return tohateyer it was doing he litre RCI. includes commands to stove the the interrupt occurred. The amount of The real -tithe control portion of' RCL. robot forward and backward, to turn left time the computer spends executing the consists of the hardware interlace. inter- and right. to stove its manipulator up and control loop must he less than the time rupt control. Iblloing-error monitoring. down, and to open and close a gripper. interval between interrupts. velocity control. and position control.

57 Low-level words timers. Setting the number of counts in the Host -primitive words deal with the the counter determines the period of a SOFTWARE SOURCES robot's hardware: turning the motors on squarewave output. The phase -locked and oft', setting the direction in which loop circuitry responds to the frequency Micro K Systems (15874 East Hamilton Place, Aurora, CO 80013, 303-693-3413) each motor rotates. and enabling the corresponding to that period. will provide the following: Commented speed -control circuits. To control the The frequency of the signal applied to source code in RE -robot disk format, the 8253's on the motor -control hoard is hardware. values must he written to and $2.00. Printed source -code listing, the 2-M11z system clock divided by 16, or read inmr various registers on the robot's $15.00. Two 27128 EPROM's with source control hoard. Those registers are read 125 kHz. Therefore a count is generated screens (and without comments) for the and written using the microprocessor's I/ every 8 microseconds (1/125.000). The R -E Robot, $39.00. With EPROM's you O statements (IN and OUT). In RCL, to 8253 is programmed to generate a square - won't need a disk drive, but you should w rite an eight -hit value to an output port, wave whose period corresponds to the val- also obtain the printed listing to read the the word P('! is used: ue loaded into the counter. So. if the comments. The Laxen and Perry F83 counter is loaded with the value 125, the Model disk with full source code and met- PC! (value port ----) for F83, in MS- total period would he 125 x 8 microse- acompiler customizing DOS 360K format, for a PC compatible "That statement specifies that value is to he conds, or I millisecond, which corre- computer, $25.00. (Very useful for learn- output I/O port pon . A wort) about sponds to a frequency of IOO() Hz. to ing FORTH if you already have a PC.) All notation is in order. The stack diagram. With a 500 -count -per-revolution en- orders must be prepaid. NO COD's. In- enclosed in parentheses. represents the coder, the motor speed would he 10110/5(1(1 clude $3.00 for shipping with each order. parameters required by the word PC! In- = 2 revolutions per second, or 120 rpm. Additional source code and applications put parameters appear to the to the left of The counter can he loaded w ith any will be available from Micro K Systems. the dashes. and output parameters appear value between I and 65.536 (0 actually), Contact them for more information. to the right. In this case there are no output corresponding to frequencies ranging parameters. from 125 kHz to just under 2 Hz. FORTH words in general (and those of sary to link a new interrupt handler into RCL in particular) make extensive use of Interrupt control the microprocessor's interrupt vector in the stack. both for parameters supplied to Motor speed must he updated many low RAM. After executing INSTALL the a word. and those that it may produce. The times per second to produce smooth ac- interrupt -control word will he executed top of the stack is always the parameter celeration and deceleration. The update every 10 milliseconds, and will continue furthest to the right. In the preceding ex- rate is set by the interrupt -control routines to do so until the system is turned oft, the ample. the slack diagram shows that the to 1(10 times per second (i. e., there are It) interrupt is disabled, or a new interrupt value to he written must he pushed on the ins between interrupts). The 80188 micro- routine is installed. stack followed by the port to which it is to processor has three built-in timers that can he wFilien. The word P('! removes these generate interrupts. Timer is used by the Position -counter words parameters from the slack, uses them. and BIOS and the DOS to maintain a time -of- The hardware position counters must leaves nothing on the stack. Other words day clock. The BIOS is set up to generate he initialized by the robot's software. In stay leave one or more values on the stack. interrupt (IICh every time timer 0 counts addition. the position counters are only 16 down to O. If we change the count value in hits wide, so the robot won't move very Motor -control words timer 0 we can use it to generate the far hefitre the counters overflow. So it's Several words operate the speed -con- motor -control interrupt. However, the necessary to extend counter length with trol circuits and the relays. For example. time-ol-day clock will count in 10 -millise- software. If we look at the counters often ENABLE and I)IS.\ISLE w rite an appro- cond periods instead of the usual 55 -milli- enough. they will not overflow. The soft- priate value to turn on or off a particular second periods, so a set of time -of -day ware maintains a 32 -hit position counter. function of the hardware. STOP -LEI' '. words will have to he defined for the new Because the counter routines must he STOP -RIGHT. and STOP use DISABLE rate. In addition, we'll have to install a executed many times per second. the time to turn the relays oft. FORWARD. RE- new BIOS -level interrupt handler to main- required to execute those routines is im- VERSE, ('W. and ('C\\' enable the proper tain compatibility. with MS-DOS. portant. So all counter routines (and sever- relays to allow the motors to turn in the First of all, we must define the interrupt al others) have been written as CODE desired direction. C\\ and ('C\\ allow routine we want to execute. "Then we can words. To experiment with those words. turns to he made by enabling the wheels to install that routine so that it is executed you'll have to know 80188 assembly -lan- turn opposite to each other. GO and each time the interrupt is generated by the guage programming. COAST enable and disable the speed - timer. The high-level words for reading the control circuits and the motor -drive cur- the word INT-OFF disables interrupt counters are ?CNTI and ?CNT2 to read

rent as well. generation by the tinier so that we can the positions of motor I and motor 2, change the interrupt vector, or disable it. respectively. The hardware causes the 16 - Speed control INT-ON turns timer-interrupt generation hit counters in the 8253 IC s to decrement Hardware on the control hoard is re- hack on. SET -TIMER takes a count that for each encoder count that is in the proper sponsible for controlling speed (accelerat- sets the period for the timer. The input direction. The difference between a ing and decelerating). The hardware frequency to the tinier is 2 MHz/3. yield- motor's forward and reverse counts gives stakes the software system much simpler ing a period of 1.5 microseconds per the absolute position of the motor. than it would he if the software were re- count. If the count is set to 6667. the timer quired to maintain speed alone. The will count downto0every 10 milliseconds Following -error words phase -locked loop on the control board and generate an interrupt. To detect a problem with the motors, it maintains the desired motor speed under GET-CS is a special word that is used is necessary to compare actual speed with varying loads. The software only has to set to return the code segment in which the expected speed. If the two differ by more the speed. and to accelerate and decele- FORTH system is executing. SET-INT than a small percentage, an overload con- rate the base unit. sets the interrupt vector to the word we dition exists, so the motors could overheat The speed at which each motor runs is want to execute each time the interrupt is and he destroyed. The following -error determined by the frequency of a signal generated. words constantly monitor the motors and that is generated by counter 0 of the 8253 INSTALL performs all the tasks neces- detect a stalled motor by comparing the

58 current motor position with the expected rated. By allowing the user to set a value position. If the difference is too great the TABLE 1-NUMERIC STORAGE for acceleration. deceleration, and max- Input Value Size DPL motors are turned off immediately. This imum speed. the behavior of the robot can 725 725 16 -1 also means that it you specify a value of he controlled precisely. -1 -1 32 0 acceleration that is too high, a firllot; ing- Before a move is actually made. the 1.2 12 32 1 error will he detected. and the motors will - 9.999 -9999 32 3 software does a series of calculations to he shut down. 38.04 3804 32 2 determine the top speed that can be attained- and the positions at which acceler- Numeric input ation should end and deceleration should FORTH normally works with 1(t -hit begin in order to attain a trapeioidal ve- 932.015 FIXED 1000 FRACTION. signed integers. Such numbers can range locity curve, as shown in Fig. I. in value from -3276 to -f 32767. In FRACTION is used by many other words Calculated speed mad he less than de- addition, a decimal point may he included to convert values liar internal use. sired speed. hut that is not a problem for anywhere in a number and FORTH vv ill short moves. \Iaxintunt speed will he treat it as a signed double -precision integ- User -input conversion words used for moves that are long enough to er with a possible range of Several words convert user -input values allow die motors to accelerate to their -2.147.483.648 to +2.1-17.453.o47. to more basic units the hardware can use maximum velocity. For short stoves. ac- the position of the decimal point is kept tier the stole commands. celeration is more important than max- in a system variable. l)PL. If a number Distances are entered in units of imum speed. without a decimal point is entered, the INCHES. FEET. MILES and DE- "Id perform a move. breakpoints on the system sets DPI. to -I. If a number is GREES. INCHES takes the value spec- trape+oidal velocity curse must he found. entered v ith a decimal point. DPL st ill ified and converts it to internal form. The Ilse points Where acceleration ends and contain the position of the decimal point input value and a scale factor are sased fi)r deceleration begins. as well as the end relative to the least significant digit en- later conversion. FEET takes a .iistance in point position. must be calculated. tered. A number may have a maximum of feet and MILES takes a distance in miles. the robot is a speed -controlled system. four digits to the right of the decimal the scale factor is .set appropriately for so the acceleration and deceleration point. the FORTH system converts the each \kord in terms of the nunther of breakpoints must he used to calculate input number to a signed integer repre- inches each stord represents. DEGREES what speed st ill be achieved by accelerat- senting the integer part and a signed integ- calculates how far each motor must move ing at the specified value of acceleration er representing the fractional pan. The to make the specified turn. to the breakpoint position. That nest pair of single precision numthers each car- Speed can he entered in miles per hour speed is saved with the breakpoint posi- ries a sign hit: the numbers can he used by using the word N1P11. inches per section. the saute values of speed and dis- alone or together. ond by II'S, feet per second by H'S, and tance are used to calculate the breakpoint

Table I illustrates how various numbers feet per minute by FI'NI. Each of those where deceleration is to begin. are stored. Keep in mind the fact that the words stores the salve and an appropriate decimal -point position stored in 1)1'1. is scale factor for later conversion. Trapezoidal velocity control correct only for the last number entered by G converts the input value (in terms of To perform a suave. the robot must he the user front the keyboard. Numhers the acceleration due to the earth's gravity, accelerated front a speed of ieru to top compiled into a definition do not affect the i.e.. 32.2 ft/sec/sec) to a count that is used speed. and then decelerated at the appro- value of I)I'l_ after compilation. lot must to accelerate or decelerate the motors. if priate point to arrive at the desired posi- he in the decimal base (base 10) when necessary. each time speed is updated by tion. The simplest system would just set entering numbers with decimals. the interrupt routines. the ;peed of the motors. turn the motors The word FIXED converts the last on until the end point was reached. and number input to an integer and a fraction. Motion then turn the motors off. That type of FIXED gets the value from DPI. and puts "Ii) move from one point to another. the approach assumes instantaneous acceler- it on the stack. then it calls (FIXED). We motors must he accelerated and decele- ation and deceleration. but in an actual defined the separate word (FIXED) to do the actual conversion, because it can he made more general-it can convert any number. even if it ttas not entered from the keyboard. EXTRACT strips the fraction digits POSITION front the number one by one until all have been removed. That leaves the integer part VELOCITY of the number on the TOS (Top OfStackI with the digits beneath it. The digits are ACCELERATION DECELERATION reassembled into a single number with BUILD. SCALAR produces a value that is used to adjust the fraction to the proper range. If the unsealed fraction is 9. ue need to know whether it is 9011)/10.1lOO. 9/10,11110. or another value. The word FRACTION takes a fraction. an integer. and a multiplier and creates a double -precision integer. So the value - 932.015 convened by FIXED is a fraction and an integer. Taking these two numbers and a multiplier of 10(111 s,ould TIME give us the double precision nit iii her FIG. 1-ACCELERATION AND DECELERATION BREAKPOINTS must be calculated in order to move -932015 as follows: the robot from one point to another.

59 system it's not practical. Therefore, we which the motors run at maximum speed. The example program shown in Listing have to take into account the acceleration For a short move. acceleration will stop I illustrates how you can combine several that actually can he achieved by the sys- before maximum speed is attained. and RCL commands to cause the robot to tra- tem. In practical terms, acceleration deceleration will start immediately after verse a square. The sequence first sets the might he a fraction of G, or it could he acceleration stops. acceleration constant to 0.1 G. Then the several GS, depending on the size of the RERB device (i. e., the base) is selected motors in relation to the size of the load. Command language to move at 25.5 inches per second. Then it To accelerate and decelerate the robot. The RCL includes a simple command moves 3.5 feet forward and makes a left velocity actually must he changed many set to allow movement of both the base turn. The latter actions are repeated three times per second. In general. the robot unit and the arm. times so that the robot ends up where it starts with a velocity of zero and then The base -movement commands allow started. accelerates at a constant rate to the top firrward and backward motion. and left Here's a short routine that moves the speed. Then it must decelerate at a con- and right turns. Maximum speed. acceler- ami down and then back up: rate it stops at the final position. ation rates, and move distance may all he stant until ARM 3.1 INCHES DOWN 2 INCHES UP The velocity -versus -time profile is also altered by user input. After each move is shown in Fig. I. but superimposed on the complete. a new move command can be By defining FORTH words we can velocity trapezoid. Note that the position executed. By defining FORTH words we create macros to perform various func- profile is not simply a straight line. In can chain several move commands to- tions. For example. Listing 2 shows a terms of calculus, position is the integral gether in a motion sequence. We'll dis- macro that will cause the robot to traverse of speed over time. The basic equations of cuss such a sequence shortly. a box of any size. motion are as follows: The arm commands move the arm up and down. and open and close the jaws. Example program V = Vo + AT Now let's show how the robot could he D = VoT YAT2 Command syntax used to collect and deliver office mail. general. a command consists of a Figure 2 shows the office layout that we where V stands tin velocity. A for acceler- In value, a distance will use in the example program. Trays for ation, T for time, and D for distance. V0 device name, a speed value, the command: incoming and outgoing mail are attached refers to starting velocity. and to the robot. From the previous equations we can [DEVICE] [n SPEED] In DISTANCE] The overall sequence of operations derive an equation that describes the dis- COMMAND goes like this: The robot starts from a tance required to accelerate from one where bracketed quantities indicate op- "nest," and travels around the corridors, speed to another: tional values that will he: the value waiting at several locations for people to D = (V2 - V02)/(2A) entered with the command: the last value retrieve and deposit mail and then returns if a new value is not included: or a default to the mail room. We can use that equation to compute the value if this is the first time the particular distance required to change speeds. We defined several low-level FORTH command is issued. The value of n de- words for the program. To allow the robot For a short move, the distance required pends on the command. DEVICE may he to wait time we de- to accelerate to the desired speed and then for different periods, KERB for the base unit or ARM fix the fined several words to execute time de- decelerate to a stop may exceed the dis- arm unit. lays. See Listing 3. The first is MS. which tance to move. In such a case, decelera- waits for specified number millise- tion must begin at some speed less than the of Base commands maximum. conds. The next is SECONDS, which The general syntax for the base -move- The word DISTANCE takes the origi- ment commands is as follows: nal speed and the desired speed (both in LISTING 1 rpm) and calculates the distance in inches [RERB] (n SPEED] [n DISTANCE] that will he required to change speeds. COMMAND .1G ( 3.22 ft/sec/sec) the distance HERB 25.5 IPS The word COUNTS changes COMMAND may he one of the f011ow- 3.5 FEET FORWARD 90 DEGREES LEFT from inches to position -encoder counts. ing: FORWARD. BACKWARD, LEFT. The word EXPECTED converts the user- 3.5 FEET FORWARD 90 DEGREES LEFT or RIGHT. SPEED may he one of the FEET FORWARD 90 DEGREES LEFT input distance to position -encoder counts. 3.5 following: MPH, IPS. FPS or FPM. DIS- FEET FORWARD 90 DEGREES LEFT -input 3.5 The word SPEED converts the user TANCE may he one of the following: maximum speed into rpm. INCHES, FEET, MILES or DEGREES. uses MS to delay the specified number of The word BREAKPOINTS calculates The command G is used to set the ac- to seconds. The last is MINUTES, which the positions on the velocity trapezoid celeration constant used to change speed: uses SECONDS to delay the specified stop accelerating and begin decelerating. the constant is expressed in G s of acceler- number of minutes. The acceleration and deceleration seg- ation. Any acceleration may he specified, Next we define several words for con- ments can't he more than half the total up to the maximum acceleration the sys- venience and to improve the readability of move distance, so the distance to acceler- tem can achieve. The acceleration may he speed is calculated the source code. The robot will announce ate from 0 to the input specified in a separate command. and compared to half the move distance. its arrival at each place it stops. That is The minimum of these two values is then Arm Commands done by sounding a beep. The word AT- used as the acceleration distance. The The basic syntax for the arm -movement TENTION generates the beep. breakpoint positions are saved in arrays commands is as follows: WARNING. sounds several short the move. beeps. It is used to avoid running over for use during [ARM] [n DISTANCE] COMMAND After the robot starts moving, the anyone when the robot is ready to move. breakpoint positions are compared COMMAND may he one of the follow- Since all the turns in our model office against the current position every time the ing: UP, DOWN, OPEN, or CLOSE. are at right angles. it's convenient to de- control loop executes to determine when DISTANCE may he INCHES or FEET. fine left and right 900 turn words, TURN - acceleration should stop and deceleration DISTANCE is the amount specified in the LEFT and TURN -RIGHT. When the should begin. If the move distance is long COMMAND direction relative to the cur- robot starts its trip it must back out of the enough. there will he a period during rent position. continued on page 80

60 VOL. 4 NO.8 AUGUST 1987 o PU ER lOES' A NEW KIND OF MAGAZINE FOR ELECTRONICS PROFESSIONALS

IBM's NEVI PS/2 Great graphics, super speed

IMa

. . I .Á + . F -, i .' ; I: 3+e+ . . : ; ', . . E: "'Jr* .. 1 . a : , ,fti -, 7 'le ' ,

DESIGN PC BOARDS ON YOUR PC New programs make it easy

1 GERNSABACK T PUBLICATION CONTENTS COMPUTER AUGUST 1987 DIGEST

Larry Steckler, EHF, CET: publisher & editor in chief

Art Kleiman, editorial director Brian C. Fenton, managing editor Jeff Holtzman technical editor Byron G. Wels, associate editor 9 Carl Laron, 11111111111111111 associate editor Robert A. Young, editor 67 MICRO-FLOPPY RETROFIT assistant Teri Scaduto Your PC can read 31/2 disks with this simple upgrade. editorial assistant Ruby M. Yee, production director Karen pucker, 1 production advertising W. Lowndes, I Robert A. - production associate -.- pt- ..,_1_. Marcella Amoroso production assistant Andre Duzant, M technical illustrator 11111111111111111 Jacqueline P. Cheeseboro ;" director ,é,- circulation Arline R. Fishman, advertising director 69 DESIGNING PC BOARDS ON YOUR COMPUTER Smartwork, AutoBoard, and other PC - ComputerDigest based CAD packages. Gernsback Publications, Inc. 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 63 EDITOR'S WORKBENCH 714-760-8967 Hardware: The new IBM's (Models 30 and 50) Cover Photo by Jeff Holtzman and Software. Memory Minder disk drive André Duzant analyzer RS -232 network program

62 EDITOR'S WORK- -2-- ill 11 c i 0

BENCH -___==- -=_-_- = _

you'll get a unique first-hand opportunity to take advantage of the new operating system 68000 UPDATE learn about operating -system design. OS/2, which we'll be lucky to see by early SKI: DOS includes a 68000 assembler, a line next year However, the low -end machine We've just finalized arrangements with editor, a 6809 emulator, floppy- and hard - (the Model 30) is not without merit; we Peter Stark, a long-time member of the disk support, extensive file -manipulation examined one, and a Model 50. microcomputing community, to do a series facilities, etc. of articles that will be of great interest to As for the MC68000 computer we pre- All aboard anyone interested in Motorola's 68000 fam- sented in the March and May issues this Tne new low-end machine can be view- ily of microprocessors, and to anyone who year, we should have the promised informa- ed as a souped -up PC or XT, depending on wants to learn about computer-system de- tion packet ready by mid to late summer. In wh3ther you get it with two floppy -disk sign from the g-ound up. The series will addition, Peter Stark has adapted SK*DOS drives or a hard disk and a single floppy It center around a gradually upgradable CPU to run on the MC68000, although no formal has a bus that is compatible with the old board that has been custom -designed spe- system of distribution has been set up. We bus, and it's a fast (8 MHz) 8086 -based cially for readers of ComputerDigest. A should point out, however, that the new machine that contains everything on the minimal system can be brought up for (and as yet un -christened) machine will system board that you normally must add about $200; it requires only a serial ASCII have better local support and distribution. via expansion cards: 640K of RAM, serial terminal or any personal computer and a All in all, we're very excited about this and parallel ports, keyboard and mouse communications program to operate. project; we hope to begin the series in connectors, battery-backed clock, and vid- The computer can be populated on- October or November For more informa- eo adapter. See Fig. 1. Other than the com- board to include one megabyte of RAM, tion, check our BBS (516-293-2283) occa- pact, lightweight system unit, the only thing floppy -disk controller, battery -backed sionally, and watch these pages for you need to get a Model 30 running is DOS clock, Winchester interface, serial and par- announcements of progress. 3.10 and a monitor allel ports, and more. It will also include 3-5 The video hardware is downward -com- IBM-compatible expansion slots, in which patible with the CGA (contrary to our re- you can plug a monochrome IBM PC display port last month), and has two new modes adapter. In addition, the motherboard will of its own, including a stunning 256 -color accept an IBM PC keyboard. (Of course, it mode that allows you to create images like will also accept low-cost clone compo- that shown on this month's cover (page 61). nents as well.) Using a PC display adapter The other new mode provides 640 x 480 and keyboard will allow you to easily create resolution in two colors, which should be a low-cost stand-alone development sys- Teat for CAD applications. The MCGA tem. (Multi -Color Graphics Array) is not com- The bare -bones system will include an patible with Hercules or EGA standards, EPROM -based monitor program called but it may be upgraded (via a plug-in card) HUMBUG, which derived its tongue-in- to the VGA (Video Graphics Array) video cheek name from a series of different BUG adapter, which we discuss below, that is IBM'S NEW MODEL 30 AND MODEL 50 programs, all of which were based on standard with the other PS/2 machines. The PC'S Motorola's original MIKBUG program, which VGA is EGA -compatible. was used in early 6800 (hundred, not thou- The Model 30 comes with a disk -based sand!) machines. HUMBUG has a number of set-up/tutorial program that allows you to commands for examining and displaying In case you missed it, IBM introduced four set time and date, park the hard -disk heads memory, etc. In addition, we hope to in- new personal computers last spring. They for moving the system, etc. The tutorial is clude a small version of BASIC in EPROM. go by the name of Personal System/2, al- extremely well-done, both in terms of the The expanded computer will run the though only the three high -end machines information presented and in the way it is SK*DOS operating system, and possibly (the Models 50, 60, and 80) have the new presented. The graphics in the tutorial are others. The author of SK*DOS also happens high-speed (and incompatible) Micro simply stunning; they drew numerous oohs to be the author of the series of articles, so Channel bus, and only they will be able to and aahs from our co-workers. The manual

63 el; in the high -res mode, each bit represents

8087 MATH one pixel. COPROCESSOR Model 30 memory mapping 8237A-5 DMA According to the Model 30 Technical Ref- CONTROLLER erence manual, the BIOS can detect the SYSTEM presence of an alternate video adapter. GATE ARRAY When it does, it will disable the on -board MCGA l 1 l and use the alternate adapter. However, the manual does not specify what type of adapter may be used in that way So we don't know at present whether Hercules, I/O SLOT 1 EGA, and other adapters will 64K ROM function in 8086 the Model 30. But you can add I/O SLOT 2 the IBM PS/2 Display Adapter, which brings CPU VGA -style graphics to the Model 30, as well 640K RAM I/O SLOT 3 as to the PC and XT models. The Model 30's 640K RAM has been im- KEYBOARD n plemented as follows. The first 128K con- MONITOR sists of four 64K by four -bit and two 64K by O... ®® Im two-bit DRAM's, all of which are soldered .::?:::.r, ::: to the motherboard. The next 512K consists IBMwarn . ZEE .. 1 VIDEO VIDEO . MEMORY , of two 256K by nine -bit plug-in SIP . . SUPPORT RAM modules. Those modules are mounted on a slant; they're visible at right side MOUSE I/0CLOCK the of the FLOPPY system in Fig. GATE BATTERY unit 2. ARRAY SYSTEM A special register (accessible at I/O port TIMER =0= 6Bh) allows each 64K segment of memory BEEPER 1 from 40000h to 90000h to be disabled in PORTS DISK case of conflict with memory on an expan- 1511 - sion card or hardware error. In addition, a rHARD special bit in that register apparently allows ...... el L e one of the upper banks to be re -mapped to J the lower 128K segment of memory in case SERIAL PARALLEL there is a hardware problem there. The BIOS POST (Power -On Self Test) handles those

FIG. 1 duties automatically

Model 30 hardware notes The Model 30 has three horizontally mounted expansion slots; they're visible at I.- the rear left in Fig. 2. The edge connectors 1 , ^a - '[ . , ' [ a for those slots are mounted to a board that = ; in turn plugs into an edge connector on the ' motherboard. The expansion -slot board T _ . f ':01.911z4;1,..1 ' . f also carries the clock/calendar's backup .v. ¡-_ >1.e battery; that battery is soldered to the u arr -T .. 1trr 1 board, and at present IBM only plans to .,a_.- 1- - replace that board as a unit when the bat- FIG. 2 tery wears out. The BIOS now supports four serial ports; is a slim booklet that will neither intimidate fonts may be stored in the 0A0000h seg- previous machines officially supported the novice nor bore the expert. ment of RAM (formerly used by the EGA); In our tests, we found no hardware or one or two active fonts may be loaded and r.- " - i software incompatibilities. Our test unit ran stored in a separate 8K static -RAM character .- M- +v... an Ethernet adapter card and a 68000 co- generator. DOS 3.30 uses the new font ca- rw i[i E414 processor card without a hitch. Tested soft- pability to provide greater support for for- i DvX . , ware includes: AutoCad 2.6, WordStar 4.0, eign languages; the new capability should Dr Halo II (version 2.15, specially for the PS 2 also ease implementing any scientific and line), Sidekick 1.56b, Direc-Link, Brooklyn engineering word-processing programs. .`Z :1 Bridge, Best Friend, PLED, and numerous The OB8000h area of memory is still used as MnY small utilities a video buffer, with characters and their = me t ..T e ... T!f attributes occupying alternate bytes of ... / .rt,t .. .. The MCGA memory .~:; 3 The Model 30's video adapter provides In graphics modes, OB8000h is still used w . ' 4j' `tsi:, better text quality than the old CGA, be- for storage in the old CGA-compatible ... : 10 s ..11111 cause each character is now displayed in an modes; in the new 256 -color and 640 x Gtl 8 r 16 box, rather than the (GAS 8 x 8 480 modes (11 and 13, respectively), the b Zn r box. However, the screen still flickers when video buffer begins at OA000h. In the 256 - iD In the text mode. As many as four character color mode, each byte represents one pix-

64 the BIOS separates keystroke scan codes from Mouse codes. All the I/O connectors are soldered to the motherboard. No external disk -controller cards (for hard or floppy disks) are necessary. The disk drive handles 720K 3W' * NOT AVAILABLE disks, as used in the IBM PC Convertible and * * NO HARD DISK many other portables. The power supply is rated at only 70 watts, but that should be suffic ent for most users. In addition, sur- 90 face -mount technology is used extensively, 80 as shown in Fig. 3. 70

60 The Model 50

50 The Model 50 can be viewed as a hybrid of an XT and an AT, with the Micro Channel 40 90 bus ( three slots) and OS/2 compatibility 30 80 thrown in for good measure. The model 50 20 ,4 70 has a 10 -MHz one -wait -state 80286 micro- to \60 processor, which is faster than the AT's mi- cropocessor; but it has a relatively slow, FLOPPY READ ' 41. \ 50 relatively small (20 megabytes) hard -disk FLOPPY WRITE \,., 40 drive like the XT. 30 The floppy -disk drive can read the 720K 20 format used by portables and the Model HARD READ lo 30; it also can read and write a new 1.44 -

HARD WRITE IBM PC megabyte format. You cannot format a 720K CONVERTIBLE diskette for 1.44 -megabyte use; special diskettes are required. The Model 50 also in- IBM PC XT cludes a megabyte of RAM, and a full DISPLAY -1í1.111 complement of I/O ports. We tested the Model 50 and found it to IBM PSJ2 MODEL 30 be uite fast. See Fig. 4 for a speed -comparison chart. The Model 50 ran all the soft- FLOATING POINT MATH ware we tested it with. 4.0, INTEGER MATH WordStar Dr. IBM PS'2 MODEL 50 Halo II version 2.15, numerous system util-

FIG. 4 ities, including a special communications program that manipulates the serial port directly-and everything we tested woked without a hitch. Of course, we couldn't test any expansion boards, because none are available yet.

,,..l ...... r The VGA The Model 50's Video Graphics Array i} , i " hardware is compatible with all previous IBM display adapters (monochrome, CGA, Ste A EGA, and MCGA), and it adds several new display modes of its own, including: 540 x 480 graphics in 16 colors (the 31:0r._3.r.( MCGA provides only two colors at that res- s.., - olution); 720 x 400 alphanumeric in 16 colors or ..

a ID monochrome; s oa 360 x 400 alphanumeric in 16 colors. Of course, the VGA can also run in the 256 -color mode of the MCGA. By way of comparison, the EGA provides 640 x 350 in 16 colors in graphics mode. Apparently, the VGA is not compatible with the Her- IOW WW1 0-__ cules monochrome standard. It's worth pointing out that all supported FIG. 5 modes will run on any PS/2 monitor That differs from most present multi -mode vid- only two. The parallel port is now bi-direc- to do exactlly that. The DMF could be es- eo adapters, which can run in various tional, so you can connect the parallel ports pecially useful in transferring data from an modes, but only on appropriate monitors of two machines together and exchange old-style machine. (ITL monochrome, color, or enhanced data between t`lem. In fact, IBM is selling a The keyboard and mouse ports are elec- color). There's much more to say about the program/cable combination called the trically interchangeable --either keyboard or VGA, but, unfortunately, no space to do so Data Migration Facility (DMF) that allows you mouse may be plugged into either port -- at this time.

65 - mob " IL IL t ot 'r!!! .. i' 't . ' irftt - E.,° ~1]° a '5 iii', - i.j

...... 5_,.._

FIG. 6

Model 50 hardware notes terrupt 15h, function 4Fh) allows you to in- MINDER, DISK -DRIVE As with the Model 30, surface -mount IC's tercept keyboard scan codes as they are MEMORY ANALYZER FROM J&M SYSTEMS are used extensively; plug-in cards extend generated (via interrupt 9). The new func- appropriate signals from the motherboard tion allows you to change the scan code, or to the floppy- and hard -disk drives. One cause it to be ignored altogether. That func- very interesting feature of the Model 50 is tion will aid remapping keys for foreign - echanical devices are always the first the modular way in which all the sub -sec- language and technical word processing, /Into go. In particular, disk drives are a tions snap together. For example, as shown but without resorting to illegal interrupt primary source of trouble. To help you spot in Fig. 5, the floppy -disk drive snaps into stealing as some word-processing and key- a potential problem before it develops into place, and the edge connector provides board -enhancing programs do. Another a catastrophe, you can take your drives to a mechanical as well as electrical contact. (A keyboard function (Interrupt 16h, function repair shop for testing. Or you can buy a plastic guide system beneath the unit locks 5) allows you to stuff the keyboard buffer disk -drive, analysis program for about the it into place.) The hard -disk drive mounts in with key codes as if those keys had been cost of two trips to the repair shop and run a similar manner, as do the bus -extender typed. the diagnostics yourself. cards, and even the fan. A number of other BIOS functions are not One such program is called Memory The Model 50 includes three Micro Chan- clearly documented, but seem to point in Minder. It's sold by J & M Systems, Ltd. nel bus slots (shown in Fig. 6); its sibling, the the direction of adding multi -tasking ca- (15100A Central SE, Albuquerque, NM Model 60 (which we didn't evaluate), pabilities to the machine. 87123, 505-292-4182), and it lists for 8114. provides eight slots and a faster hard disk. DOS 3.30 is not a major upgrade, but it is The package consists of three parts: a man- not insignificant either. It contains greatly ual, a disk containing the control program, Monitor mania expanded support for foreign -language and a special test disk. The program disk There are several monitors available for all character display, extended network sup- uses the test disk to check drive speed, the new models; two are color displays port, and extended batch -file support, in- head and clamping alignment, and several (8512, 8513) and one is monochrome cluding a CALL command that allows one other factors. (8503). They all have the same resolution batch file to call another. (CALLing was pos- (720 x 400 in text mode, 640 x 480 in sible but awkward in previous versions of How to run it graphics mode); they differ mainly in price DOS.) The new DOS also supports all disk First you boot your machine directly from and size. Our cover shot was made with the formats, ranging from the single -sided sin- the Memory Minder program disk. It then 8512 monitor, a 14 -inch model. gle density (160K) 5Y4 format of the original displays a menu that lets you select param- The new monitors are analog types, PC to the 1.44 MB format of the models 50, eters and run tests. After booting, the pro- which means that they are incompatible 60, and 80. DOS 3.30 runs on all past and gram disk is no longer needed; at that point, with the previous standards, although NEC present models of the PC. you insert the Digital Diagnostic Disk (DDD), has announced that their MultiSync monitor manufactured by Dysan, into the desired Is compatible with the addition of a cable Conclusions drive. Disks are available for testing several adapter. The new monitors are plug -com- All in all, the PS/2 machines represent real types of drives. patible with each other; the BIOS senses technological improvement in the PC family From the main menu you first run a clamp whether a color or a monochrome display They are not a radical departure from past test (shown in Fig. 2), which tests the ac- is connected and routes signals according- systems, nor are they misplaced machines curacy with which a diskette is clamped. If ly If a monochrome monitor is attached and like the PC Jr and the PC Portable. Rather, your drive can't pass the clamping test, a color mode is active, the RGB signals are they represent an incremental step in the chances are it can't pass any other tests summed and output to the monitor via the evolution of the PC family They're not the either. (It's also possible that the DDD has DAC (Digital -to -Analog Converter) that cheapest machines, but they set standards gone bad, in which case it must be re- controls green. that others will follow We applaud IBM's placed for the healthy sum of $40.) It's unclear at present whether two leadership efforts, and hope that it will con- Then you run a quick test, whose screen monitors can function simultaneously; tinue in the course it has set itself. appears as shown in Fig. 7). If your drive fails some CAD programs and debuggers use any aspect of the quick test, you can run one screen for menus and control functions, Credits more -detailed tests. For example, spindle and the other for program output. Media Cybernetics (8484 Georgia Ave., speed may be measured directly in RPM, Suite 200, Silver Spring, MD 20910, and, if speed varies from the standard (300 New BIOS and DOS 800 -446 -HALO) graciously sent us a beta - RPM for a 51/4 -inch drive) by more than The following discussion refers to the test copy of version 2.15 of Dr Halo, which ± 2%, the program tells you so. Model 30's BIOS and DOS 3.30. A new supports the new video hardware; we Another test checks the drive's head BIOS interrupt 10h function call (12h) used it to create our cover image. And alignment. J & M provides generic instruc- provides a means of switching various vid- thanks to AutoDesk, Inc. (2320 Marinship tions for aligning a head, and wisely refers eo adapters on and off. Again, it's unclear Way, Sausalito, CA 94965), for sending a test you to the manufacturer's alignment instruc- whether external Hercules, EGA, or other copy of AutoCAD version 2.6. Thanks to tions. Other tests check other aspects of the adapters are supported. Andre Duzant for cover art, and to Herb drive's operation, and a special set of rou- Another new BIOS interrupt function (In - Friedman for cover photography.gm« continued on page 72

66 MICRO R ROfi IT

-:. ,rt.+'tN

J )

\ W11111\1\111111

Retrofit your PC or XT with a 31/2 -inch disk drive.

HERB FRIEDMAN

If you use an IBM PC or done, you may be underwhelmed by all the fuss being made about 3%h-inch disks. However, many portable computers, and all of IBM's new line of PC's, use 3Y2 -inch disks. (See "Editor's Workbench" for reviews of two of the new PC's.) The 45' small diskettes have many advantages over the 51 -inch disk you're used to using, including: Increased capacity (two to four times that of a standard 360K floppy disk) Ir/ Greater reliability, because each disk is completely enclosed by a hard plastic shell Smaller, shirt -pocket size 51/4 -inch disks are by no means obsolete, but chances are that the industry will move steadily toward use of 3'h -inch disks, Just as 8 - inch disks were gradually supplanted by 51/4 -inch disks. So in this article we'll show you how to retrofit your computer to use 3'h -inch disks. Then you'll be ready to handle the upcoming new wave of software and data. We'll discuss installation of IBM's model FIG. 1-THE CABLE FROM THE 31/2-inch drive has its own power 2683190 disk -drive retrofit kit for PC and XT model computers. connection take -of that matches the miniature power socket on Similar kits are available from clone manufacturers, but installation the supplied Y-adapter. The ring through which the adapter's may differ, so your drive's instructions carefully power wire loops is a toroid choke that help suppress RFI. What it is The retrofit kit consists of a cabinet -mounted P.-inch disk drive power from your computer's internal disk -drive power connector with attached signal and power cables, a Y-adapter that lets you tap (shown in Fig. 1), and a kit of three pre -punched metal brackets

67 (shown in Fig. 2) that accept the Y-adapter's connector. 4,1 r r.Yl :r4 14'04 Installation is simple. First you mount the appropriate bracket or , = ----`r the rear apron of your computer. Then you install the Y-adapter in - series with one of the existing internal disk -drive power connectors. Next, you push the small power connector through the hole in the bracket. That connector locks in position by means of mounting ears molded on the connector. Finally, you connect the cable from the 3Y2 -inch disk drive to the controller card in your main computer With some PC's you won't need to install the power cable in series with the floppy power connector The reason is that the ;_" power supplies in some PC's have four power connectors. So, if you haven't used used all four; just connect the Y-adapter to one of IWZILkm, FIG. 4-THIS ISr-A TYPICAL CLONE INSTALLATION The disk the unused connectors. controller socket and the 31/2 -inch drive's power socket are on the least inconvenience. For exam- Use the bracket that causes adjacent brackets. ple, if you use the relatively large standard rear -slot bracket shown in Fig. 2, you must give up an entire slot. Some PC's have only five slots, so it may prove impossible for you to use the large bracket. In that case you could use the smallest bracket, which will mount in the small hole above the cassette port (yes, the original PC included a cassette interface). The medium -size bracket can be used in the extra slot above the keyboard port on an XT. Clone panel layouts may vary, so you might have to use the full- J,

size bracket and give up a slot. Or you might just cut a hole of your j. own in which to mount the small bracket. s

Standard controller :9. To use the adapter, you must have an an IBM -type floppy -disk controller; the kind with a 37 -pin D -connector on the mounting bracket (as shown in Fig. 3), in addition to the regular floppy -disk

:moo -

FIG. 5-CONNECTORS IN PLACE AND READY FOR USE. The 37 -- pin D -connector is a real heavyweight, so be certain that you tighten its mounting screws to ensure reliable operation.

connector. The IBM controller accommodates four floppy -disk drives: two internal and two external drives. Because the retrofit kit connects to the computer via the external 37 -pin connector, you cannot use a multi -function disk controller (the kind that combines a disk controller; serial and parallel ports, a joy-stick interface, and a clock), because it has no connector for external floppy -disk drives. IBM device; having the FIG. 2-THE RETROFIT KIT is supplied with three different The controller itself needn't be an actual brackets for the power sockets. Use the one that's most conve- external connector is the important point. nient for you, but remember that the standard bracket (the large Figure 4 shows an XT clone ready to connect the 31/2 -inch disk one) may force you to give up use of one expansion slot. drive. The external disk -drive connector is adjacent to the miniature power connector installed in the slot furthest left. To install the 31/2 -inch drive, simply plug the appropriate connectors from the drive in the appropriate jacks, as shown in Fig. 5.

Device driver Before you can use your new drive you must tell the computer that it's there by adding a device driver to your computer's CON- FIG.SYS file, the configuration file that's automatically read when the computer boots. For example, adding the line:

DEVICE = DRIVER.SYS /D:2

to your CONFIG.SYS file will allow you to access a 31/2 inchdisk drive as the next available drive (D: on an XT). IBM's device driver comes only with DOS versions 3.20 and 3.30. (Some clone manufacturer's drives are available with drivers that work under DOS 2.11.-Editor) The device driver informs your computer that the 31/2 -inch drive exists, establishes its physical parameters, including number of FIG. 3-IBM-TYPE DISK CONTROLLER cards have a 37 -pin socket on the rear for external disk drives (C: and D:). The retrofit cable tracks, sectors per track, number of heads, etc., and sets the drive's must connect to that socket. logical designation (D:, E:, F:, etc.).

68 DESIGNING PC BOARDS ON YOUR

. ' COMPUTER - v\N»lurr' i

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ROBERT GROSSBLATT

Last time, in the June issue, we examined CAD (Computer Aided you want connected together smARTWORK will do its best to lay in Design) in a general way, seeing what kinds of things you can do the traces. (or should be able to do) with any worthwhile CAD package. This The Wintek program only does the PC -board layout; there's no month we'll look at several specific packages, focusing on those way to draw the schematic, generate a netlist, and have the router that are of special interest to the electronics enthusiast. read the file. So using smARTWORK is in some ways similar to doing There are a number of packages on the market, and both price a layout by hand or graph paper and performance vary considerably. However, none of the pack- smARTWORK is simple :o use. After loading the program and ages we reviewed are inexpensive. As we've seen, a layout pro- creating a file, you begin your layout by placing the doughnuts and gram must contain several different but integrated parts, so a pads. The coordinates of the cursor are always shown on the complete package represents a substantial investment in develop- bottom of the screen; that makes it simple to put a component in a ment In time. addition, the potential market is small, certainly much precise location in the workspace. There are a variety of pad shapes smaller than the markets for word-processing and database pro- available, as well as commands to create various patterns for IC's grams. So development costs and market size translate into rela- (SIP and DIP layouts, for example) headers, and so on, automatically tively high prices. The finished layout is really the parts -placement diagram for the board you're designing, so it's a good idea to work out a rough idea smARTWORK of where things are to be placed before you start smARTWORK. The Wintek Corporation markets a package called smARTWORK, Doing so will make t easier to avoid going beyond the edge of the which probably is the most popular of the "inexpensive" routing board as well as to take in:o account any of the special placement packages. It has a graphics editor, router, and is capable of produc- considerations we've already mentioned. It's easy to make adjusting high -quality output. The program is an "interactive" router- ments to the board when you begin routing the traces because what we call a point-to-point router. After you place the compo- smARTWORK's graphics editor has a set of commands to let you nents, you can draw traces yourself or tell the router which points move, stretch, delete, and fill.

69 When you start routing traces, smARTWORK will let you do either a single- or a double -sided board, with an optional silk-screen layer. However, keep in mind the fact that the program can only 0 handle two routing layers. If you want to do multilayer boards, you'll have to use another package. Each layer can contain two trace widths, thin and fat, and although you can choose between three preset thin widths, you can only use one on each layer. The fat width, 50 mils, is the only one available, but you can produce a fatter trace by laying two or more traces near each other. Routing can be done either by hand or by using the routing algorithm built into the program. However you do it, chances are that you'll want to rearrange traces as the layout develops-and that's where you'll appreciate the power of the graphics editor. It's easy to change anything on the board-it's really as simple as moving text around in a word processor. When the design is complete, you can get hardcopy from a dot- matrix printer in either actual board size or double size. There are FIG. 2-SMARTWORK also produces quality copy on a dot-matrix printer. commands to control the intensity rotation, and size of the printed output. As shown in Fig. 1, a much higher-quality printout can be obtained by using a plotter; smARTWORK supports several. Which- (smARTCAD) that converts smARTWORK files into AutoCAD format. ever device ycu use, smARTWORK will generate camera-ready art (We discuss AutoCAD below.) When you do convert a file, each for photochemical board fabrication. Wintek can supply you with side of your PC board will be on a separate layer, and you can use information about hardware compatibility. any AutoCAD editing command to do things you just can't do with Wintek markets another program called HiWIRE, a graphic sche- smARTWORK. For example, you can: matic -drawing editor, and they're currently working on software Add text in any size and font. that will let the tv programs share common data files. Contact Place pads for odd -sized components. them directly at the address shown in the sidebar for more detailed Increase board size beyond 10 x 16 inches. information Use a different grid spacing. Another company (Creative Electronics) is marketing a program Prepare a solder mask.

Project:PCB A new low-priced entry is called Project:PCB; it's made by DASOFT Designs, Inc., and it has many features that are missing from smARTWORK, including a means for schematic capture and a true auto -router The circuit diagram can be entered with a graphics editor; the program can extract the netlist directly from the drawing. You can also enter and edit connections in text form directly from the keyboard. The software comes with a limited component library, but you can use a parts editor to build new parts that can then be called up automatically when you're entering a schematic. In fact, Project:PCB actively encourages you to create symbols and share them with others; the company has set up a bulletin board (415-486-0862) where users can share custom parts and libraries, and where the company will post information on updates, bug fixes, new versions, etc. To use Project: PCB, first you create the schematic. When it's finished, you use the layout editor in a graphics mode to define the overall shape of the board and to place the components. Then you're ready to route the board. It can be done automatically with Project:PCB by selecting the Route option on the menu, or you can enter traces manually before turning the router loose on the layout. One of the nicest features of the program is the ability to tell the router to do only a single net and then stop. That means that you can pre -route power and ground lines, for example, before going on to the rest of the board. The router goes over the board twice. But you can set it up to do only one side of the board and then stop. That gives you the opportunity to try to improve the layout by hand, and then have the router go through that side again. Doing the layout that way can be valuable, because feedthroughs are the inescapable consequences of double -sided boards, and plated -through holes are difficult to do at home and expensive to do commercially Project:PCB can deliver hardcopy to a variety of plotters, but printer output is lim ted to text dumps of the various data files that i are generated by the program. If you have one of the plotters supported by the program you'll get beautiful camera-ready art- .evovool work that's perfect for board production. The program has more stringent hardware requirements than for FIG. 1-- SMARTWORK produces high -quality camera-ready work when - smARTWORK. Much of the equipment (mouse and plotter, used with a good plotter. example) that is optional with smARTWORK is required to run

70 Project:PCB. But Project:PCB has a much more extensive graphics package, as well as an auto -router. TABLE 1-PFOGRAMS DISCUSSED

Autoboard smARTWORKS The Wintek Corporation At the other end of the price/performance spectrum is a program 1801 South Street called Autoboard. It is designed for serious production. It has every Lafayette, Indiana 47904-2993 feature we've already discussed, and many, many more. In fact, $895.00 Copy Protected comparing it to the packages we've been discussing is like comparing a Ford to a Ferrari-they're in different leagues altogether. Of course, the added capabilities don't come for nothing. Project: PCB DASOFT Designs Systems, Inc. P.O. Box In order to concentrate all their energy on the routing package, 8088 the Great Softwestern Company decided to look elsewhere for the Berkeley, California 94707-8088 graphics editor. That was a wise decision. $950.00 Hardware Locked Autoboard, in addition to its auto -router, is a collection of over- lays, script files, menus, macros, and drawings to turn AutoCAD into The Autoboard The Great Softwestern an electronics graphics package. It goes without saying that Auto - System Company, Inc. CAD is one of the most powerful and most supported graphics 207 W. Hickory St. Suite 309 editors on the market. So one of the great strengths of Autoboard is Denton, Texas 76201 that it makes full use of AutoCAD. The schematic and board layout are entered in AutoCAD; Autoboard's custom menu system makes $2500.00 Requires AutoCAD it simple to do so. AutoCAD Inc. While building the schematic or the board, you can use any of Autodesk, Marinship AutoCAD's awesome range of commands to edit the drawing 2320 Way Sausalito, 94965 you're working on. The parts library from Autoboard is extensive, California and you can create new parts by building their definitions in a word $2850.00 (Version 2.5 or above) processor-a straightforward procedure that's described in the manual. smARTCAD Creative Electronics Autoboard is designed for commercial board fabrication, so it 925 Fairwin Ave. has some impressive capabilities: Nashville, Tennessee 37216 1. It can route boards up to 16 layers thick. $395 2. It can handle more than 1000 components on a board. 3. More than 40 buses can be defined. 4. You can have as many IC arrays as you want. 5. More than 1000 pins can be tied together. 6. Board dimensions can be up to two feet square. The fourth item in that list deserves a little explanation. Some IC's (memory devices, for example) are put on a board as a block, and the traces that connect them are laid out in a standard fashion. Autcboard has built-in algorithms to generate those traces, and there are routines in the graphics editor to place the IC's on the board with proper spacing. The best way to indicate how Autoboard works is to describe the process of creating e board. Remember that you must own a copy of AutoCAD (and know how to use it!) in order to use Autoboard. The first step, as with Project:PCB, is to tell Autoboard about the schematic you're using. There are a series of batch files that do all the setup work for you (ooen data files, call up AutoCAD, and load a series of custom menusand scripts). Parts are chosen from menus along the right side of the screen; AutoCAD prompts you for orientation and location. As you move the cursor around the screen, the cart you're working with drags along until you place it. Next you're asked for the part'; number and value. Last, AutoCAD draws the part ú on the screen along with the other information. When the parts are all placed and identified, you connect them together using either AutoCAD's Line command or the Line macro in the Autoboard menus. There's a difference. Autoboard's Line com- ilZ1111~c,, mand will automatically place the line in the correct layer for the 1 software that reads the drawing file and generates the list of connections. You can switch between layers using the normal AutoCAD commands, but it's simpler to use the macros. When the drawing is sized, titled, and completed, a special command converts the schematic information to a netlist for use by the rest of the program; it also makes sure you don't have any unconnected components or lines. If it finds any, it lets you know by J I listing them on the screen as text-but that's not all.

1 One of the layers that Autoboard defines when it sets up Auto - CAD is called the Warning layer If there are any uncommitted pins, unterminated lines, etc., Autoboard will return you to AutoCAD, FIG. 3-AUTOBOARD routed this board automatically using a schematic and the points in question will have small red circles around them. created with AutoCAD.

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*war d.0e ,RiAA Cy..M: ,ti, .« Ileratt., hobbyist use. However, if you split the cost EDITOR'S WORKBENCH ...r Y.. 111,1511 11S1-4 among several persons, each of whom continued from page 66 ' :." might use the program two or three times a year, Memory Minder is worthwhile. The

04.4. 10 manager of a small office with a number of MfN aattl-ItY . . tines aid in performing a traditional align- 11115l . . PC's easily justify the cost of the pro- 11114.1.Nr1 could ment by allowing you to position the head o11~. 0e gram, and if he uses it conscientiously, it to any track. AlyN.1 «..,a1.), Ado valuable data from being .MI. could prevent Each test is activated from its own screen lost, make an very rx rMtl., . and thereby employee from which you can select the drive to test, ,t,«t;W, me happy the head (0 or 1) to test, and the location on G,. Old . TT It iota a r4'.= What to do with the information Memory the DDD to test. You can print any screen by Minder provides is If you have FIG. 7 another story choosing the appropriate menu item. In ad- no experience aligning disk drives, it's dition, a setup screen allows you to estab- you can continue to use the disk after the probably best to leave well enough alone, lish specific operating characteristics, first set wears out.) unless you're willing to experiment and including disk type, serial -port parameters, possibly pay the consequences. But as a main or alternate test tracks, etc. (The alter- Recommendations diagnostic aid, Memory Minder is a well - nate tracks on the DDD are provided so that Memory Minder is rather expensive for thought -out, easy -to -use product.im$

72 from A: to B: on a machine with only a single floppy -disk drive, you MICRO -FLOPPY DISK DRIVES know how it works. For example, assume that you have a single floppy drive and a continued from page 68 hard disk. The floppy functions as drives A: and B: and the hard disk functions as drive C:. You can install two device drivers that tell the You can access the disk like this: The 31/2 -inch drive is automat- computer that the 31/2 -inch drive will function as both D: and E:. ically assigned the next available drive letter (after all floppies and Now there's no problem copying files between separate 3'/º -inch hard disks, if any). For example, if your hard disk is drive C:, the 31/2 - disks via a single drive. The computer will prompt you when to inch drive becomes drive D:. If you have two hard drives, C: and D:, swap disks. the 31/2 -inch drive becomes drive E:. If you have no hard disk, but You might prefer to do it this way: Use the motherboard's DIP you do have a RAM disk set up as drive C:, the 31/2 -inch drive again switch to program four floppies, even if you have only two. The becomes drive D:. hard disk automatically becomes drive E:. Configure the device driver so the 31/2 -inch drive is C:. That will leave D: free for use as a Logical and physical RAM disk. Then the entire disk lineup will be A: and B: as 5Y4 -inch You may wonder whether you can copy a file from one 31/2 -inch floppies, C: as a 31/2 -inch floppy, D: as a RAM disk, E: as the hard disk, diskette to another without going through an intermediary device and F: as the second logical designation for the 31/2 -inch floppy such as a hard disk, a RAM disk, or even a 51/4 -inch floppy disk. You Setting up the device driver can become somewhat compli- can (using DOS 3.20 or DOS 3.30). What you do is enter the device cated, but bear in mind that, when it's over, to interchange data driver program into the CONFIG.SYS file twice. For example: between any combination of disk drives, you can use the normal DOS COPY command. DEVICE = DRIVER.SYS /D:2 One final point: There are a number of different 31/2 -inch disk DEVICE = DRIVER.SYS /D:2 formats. For example, the Tandy Model 100 disk drive has one The computer is then fooled into thinking that there are two format, the Macintosh comcuters have another, and IBM now has physical 3Y2 -inch drives with different logical designations (D: and two of its own, both high-density(1.44 megabyte) and low -density E:, for example). DOS will prompt you to switch disks when that is (720K). The high -density format is used only in the new Models 50, appropriate. 60, and 80; the low -density format is used in the new Model 30, That's not as complicated as it may sound. It's really the same IBM's laptop, as well as laptops from a number of manufacturers capability we've always had with the IBM, but extended to handle (including Zenith, Toshiba, etc.) The upgrade described here can more drives and more types of drives. If you've ever copied a file read only the low -density IBM format.+CD«

tion because it constantly reports its progress on the screen. Our COMPUTER DESIGNED PC BOARDS example board was one that had already been done by hand (we showed it last time), and it was amazing, to say the least, to watch continued from page 71 Autoboard do in 15 minutes what had taken two days to do by hand. The only consolation was that all connections were made in To correct a mistake, you can connect an uncommitted point using the hand -routed board, but Autoboard missed five (out of a total of the Dot command, which draws a small blue circle there and 115). That's not a bad percentage, and it's a safe bet that tweaking informs Autoboard that you want a connection. If the pin was left the configuration file could result in a success rate of 100%. open by design you can just ignore the warning. The last thing the router does is call up AutoCAD, draw the board The next step is to define the board and place the parts. Once on the screen, and display all the traces it has finished. It creates a again, Autoboard has a set of files that customize AutoCAD with separate "rats-nest" layer for the missed routes and draws them on menus and macros. After the board outline is defined, you can that layer in a different color. It also creates a text file with a .BAD begin laying the parts out in much the same fashion you did when extension that lists all the connections it missed. By the time reach the schematic was drawn. Picking a part from a menu allows you to this point, you're in AutoCAD looking at the routed board with each drag it around the screen and place it exactly where you want it. board layer in a separate , utoCAD layer (including separate ones It's a tremendous help to use AutoCAD's Zoom command to zero for the pads and the silkscreen). Now is when you'll appreciate the in on a location if you're placing a small part. The drawing of the fact that Autoboard works inside AutoCAD. You can use any Auto - part you drag around the screen will be enlarged by the same CAD command to do anything you want to any layer-you have amount, so you'll be able to judge relative placement and size. complete control of the drawing. Once you've picked the insertion point, you'll be asked for the When you're happy with the layout, you can use any of Auto - name of the part and its value. They must be consistent with those CAD's normal output commands. So you can create a text file that you used in the schematic entry phase, because Autoboard's router describes the board (for conversion to FutureNet, Gerber, etc.), or uses those names to identify the parts and also the connections in you can print it, plot it, etc. AutoCAD knows how to talk to virtually the netlists. every printer and plotter ever made, so you can be confident it will When you complete the layout, you can hand -route some traces talk tc yours. And AutoCAD files are one of the few standards for if your circuit has requirements you're afraid won't be properly graphic data. As for input devices, some sort of digitizing tablet is addressed by the router. Next you'll want to turn the auto -router tremendously helpful in drawing both schematics and layouts. loose; that's done simply by giving it the name of the board you And, as with printers and plotters, AutoCAD knows how to talk to want routed. just about all of them. The keyboard, of course, can be used alone Autoboard is an open system in that all the menus and script files or in conjunction with a digitizing tablet. (and many other parts of the program) can be customized to fit your requirements. The same is true, to a lesser extent, of the router. Conclusions There are a series of "switches" you can set in the router that control Each of the packages we've been talking about is a well -thought- things like the number of allowable layers, minimum and maximum out piece of software, and each is updated occasionally All the pad and trace widths, spacing, time limits, and so on. That is easily graphics produced for this article were done on an IBM PC XT with a done by editing a configuration file with a word processor. The Sigma Designs Color400 Video Board, an SR -12 monitor from router automatically looks for that file when it starts to run. If it can't Princeton Graphics, and a Summamouse from Summagraphics. find it, it uses its default values. And a very special bit of thanks must go to Dennis Jump for There's something magical about watching the router in opera- standing by the phone.m$

73 anese, and North American firms ready to be replaced, a serious SATELLITE TV all have such systems operating - effort should be made to adopt continued from page 29 like the NTSC/PAL/SECAM de- new standards it will resolve the velopments, no two of the pres- 50 -year old problems related to ently developed systems share the multiple, non -compatible sys- end up selling the TV viewers a same standards, so we're back tems. Untortunately, it will require better picture in order to attain an with the same old problem. uncommon resolve to push the international standard. Many engineers believe that strong nationalistic instincts into Why an international fuss about there is general worldwide ac- the background in favor of a sin- the technical nitty-gritty that goes knowledgment that we must avoid gle, worldwide -technology stan- into a TV picture? Because there is entering the era of fi[)TV with dard. If it happens, it will be the a crying need for a universal televi- three different "national stan- first time that the world has agreed sion standard. High-tech com- dards," and that since the present- on an important broadcasting munication systems, such as day transmission standards are standard. R -E satellites, can now beam a TV picture trom any part of the world to any TV set, so there must be a con- REPRINT venient way for everyone to view programming from any spot on the Radi.-Electronics, BOOKSTORE SP1 Special Projects #1 $6.00 104 Radio -Electronics back issues (1984) $5.25 globe. Since there are three wide- SP4 Special Projects #4 (Summer 1982) $6.00 (December 1984 issue is not available) ly -used television standards now SP5 Special Projects #5 (Winter 1983) $6.00 Write in issues desired in use-NTSC, the North Amer- SP6 Special Projects #6 (Spring 1983) $5.00 O 103 Radio -Electronics back issues (1983)....$5.75 SP7 Special Projects #7 (Summer 1983) 56.00 (Jan., Feb., May are not available) ican or US standard; PAL, the basic SP8 Special Projects #8 (Fall 1983) 56.00 Write in issues desired all -Europe standard; and SECAM, SP9 Special Projects #9 (Winter 1984) $6.00 102 Radio -Electronics back issues (1982) $6.50 the joint French -Russian stan- SP10 Special Projects #10 (Spring 1984) $6.00 (Jan., Feb.) is not available) 111 Hands -On Electronics #1 S5.00 Write in issues desired dard -the exchange of television 112 Hands -On Electronics #2 $5.00 101 Radio -Electronics back issues (1981) .. 57.00 programming such as the Olym- 113 Hands On Electronics #3 $5.00 (Issues available: July, Aug. Sept. Nov ) 114 Hands -On Electronics #4 $5.00 Write in issues desired pics, and news feeds, and even O 115 Hands -On Electronics #5 $5.00 153 Etch your own PC boards $3.00 family programming, has been a 115A Hands On Electronics #6 $4.00 154 How to Repair VCR's $3.50 burden because the equipment O 116A Hands -On Electronics (Jan -Feb '86) $4.00 155 IBM Typewriter to Computer $3.00 O 116B Hands -On Electronics (Mar/Apr '86) $4.00 O 125 Radio Electronics Annual 1985 $3.50 that converts one TV standard to 116C Hands -On Electronics (May,Jun '86) $4.00 126 Radio -Electronics Annual 1986 $2.50 another is expensive and prone to 116D Hands -On Electronics (Jul/Aug '86) 54.00 156 How to Make PC Boards 52.00 failure. O 116E Hands -On Electronics (Sep/Oct '86) $4.00 157 All About Kits $2.00 116K Hands -On Electronics (Nov '86) $4.00 158 Electro Importing Co. Catalog (1918) 55.95 While it is possible to manufac- O 116L Hands -On Electronics (Dec '86) 54.00 159 Low Frequency Receiving Techniques ture a receiver capable of receiving O 117 Hands -On Electronics back issues (1987) 53.50 Building and using VLF Antennas $6.00 Write in issues desired 160 New - 42 the three types of TV they Ideas Circuits $3.50 signals, 150 TV Descrambler $3.00 161 Descrambling (Feb., 1984) $2.00 are, and are likely to remain, pro- 0 151 Build Your Own Robot $12.00 162 Build Your Own Satellite TV Receiver $7.00 hibitively expensive. Multi -stan- O 152 8 -Ball Satellite TV Antenna $5.00 163 Receiving Satellite TV $7.00 107 Radio -Electronics back issues (1987) $3.25 164 Modern Electrics (April, 1908) $3.00 dard receivers, such as those that O 106 Radio -Electronics back issues (1986) $3.75 165 How to Repair CD Disc Players $5.00 are available in small quantities in Write in issues desired 166 Collected Works of Mohammed Ullyses Fips Europe and the Middle -East, are 105 Radio -Electronics back issues (1985)..54.25 (62 pages, April Fools Collection) .... $10.00 (Jan. 85 not available) 167 Designing With IC's $4.00 not cost-effective because a major Write in issues desired portion of the circuitry must be To order any of the items indicated above, check oft the If you need a copy of an article that is in an issue we duplicated, even triplicated, to ac- ones you want. Complete the order form below, include indicate is unavailable you can order it directly from us. your payment, check or money order (DO NOT SEND We charge 50C per page. Indicate the issue (month & commodate the different trans- CASH), and mail to Radio -Electronics, Reprint Depart- year), pages and article desired. Include payment in mission standards. ment, P.O. Box 4079, Farmingdale, NY 11735. Please full, plus shipping and handling charge. Make checks allow 4-6 weeks for delivery. payable to Gernsback Publications, Inc. Whose HDTV? Television formats, as we know ARTICLE them today, originated in the 30's and 40's. (NI SC color was appen- PAGES MONTH YEAR dixed to an existing black -and - white standard in the 50's.) Even it we could conveniently and inex- TOTAL PAGES 0)50C each TOTAL PRICE

pensively interchange the signal MAIL TO: Radio -Electronics formats, all of the systems, NTSC, Reprint Bookstore, P.O. Box 4079, Farmingdale NY 11735 All payments must be in U.S. funds PAL, and SECAM, realize approx- SHIPPING CHARGES IN USA & CANADA $0.01 to 55.00 $1.00 $30.01 to 40.00 . . $4.75 OUTSIDE USA & CANADA

imately halt of the picture defini- $5.01 to S10.00 $1.75 540.01 to 50.00 . .. $5.75 Multiply Shipping by 2 for sea mail tion that's possible using 1980's $10.01 to 20.00 $2.75 550.01 and above .. $7.00 Multiply Shipping by 4 for air mail 520.01 to 30.00 $3.75 technology. Total price of merchandise Although present technology Sales Tax (New York State Residents only) $ Shipping (see chart) $ makes a 1,000- to 1,200 -line video transmission system do -able at Name Total Enclosed $ consumer prices -European, lap- Address R-8-87 City State Zip 74 PC SERVICE

i r 4e1

, -\_ \ t1) -,, --- L,t o zL=. 1I o .o".Yo1 1

.fib I..s..I.s...aii t lliiii 7//

I- 5 INCHES

USE THIS BOARD to assemble the digital tachometer's display board. The article appeared in the June 1987 issue.

+10+

4 1/16 INCHES i he --1 INCH

THE MAIN BOARD for the digital timer is shown here. You can find the story beginning on THE DISPLAY BOARD for the digital timer is page 45. shown here.

75 PC SERVICE

76 = 10.8/0.067 mA = 160,00(1 ohms. AMP DESIGN Resistor RI is the most critical resistor + 12V continued from page 50 in the circuit. To ensure nrtsinnun uoltage swing. it should brine the quiescent collector voltage to one halt the supply volt- = 10.8/0.067 mA = 160,00(1 ohms. + Vcc Resistor RI is the most critical resistor Rc in the circuit. To ensure maximum voltage 470011 swing. it should bring the quiescent col-

lector voltage to one hall' the supply volt- R1 age. After building the circuit, the value 160K of RI may have to he varied slightly to achieve tha: voltage swing. R1 We Q1 now have a circuit we can test. 1 C2 .33µF C1 Interfacing 1.0µF R2 o OUTPUT BASE BIAS Connecting the circuit to the outside 22K VOLTAGE world will require capacitor coupling. RE DIVIDER That sexes to isolate the AC signal Isom INPUT 470(1 Rt 50K any DC bias voltages. Figure 3 shows our complete circuit with input and output

R2 coupling capacitors. the values of those capacitors were calculated using C = I 1/(3.2 x / x R). where C equals the capacitor value in farads. fequals the fre-

quency at which response will he down I FIG. 3-CAPACITOR COUPLING Is required to dB. and K equals the impedance on the interace the amplifier to the outside world. load side of the capacitor. To calculate the value of CI, the amplifier's inpui impedance (I5 f; l is used for R. FIG. 1-A COMMON -EMITTER AMPLIFIER was To calculate the value of C2, the input +12V the ideal solution to our design problem. impedance of the next stage (501;) is used for R. the value of CI can now he calculated +12V fbra drop ofIdliat2011/:CI = 1/(3.2 x 20 x 15000) = .00(100104 farad = 1.0 µF. "Ihc value of C2 = 11(3.2 x 20 x 5(1(11111) .11(1(1(1(1031 = farad = 0.33 µF. RI 10 increase the gain of the stage. you 160K could bypass R with a capacitor. as show n in Fig. 4. Nothing conies for tree. R1 Rc 160K 47009 however. The price you pay for increased gain is lower input impedance, which will vary widely with beta. It' that variation is Cl I.OµF R2 EMITTER not a problem. a significant gain increase 22K BYPASS can he realised by adding the bypass ca- 0 C3 pacitor. Our original circuit has a gain of INPUT 10: it the emitter is bypassed the gain 1350µF becomes Re/0.03/1 r = 4700/(0.03 / 0.00129) = 4700/23 = 20(1. the value of the bypass capacitor in farads is calculated from the formula C = i 1/(6.2 x /' x RI. Again f is the low - frequency limit in IIz, and R is the dy- FIG. 4-INCREASE GAIN by bypassing the emit- namic emitter resistance (0.03/1,;). In out ter resistor as shown here. example. if we stick to a 20-11-i lower limit we have C = 1/16.2 x 20 X (0.(13 but it can he modified to run on any other 0.110129)1 = .0011344 farads = 344 µF. system. FIG. 2-SIMPLE CALCULATIONS yielded the 350-µF unit can be used. A few thoughts on components hebore component values shown here. we finish: Using 5.(4 resistors allow s Computerized calculations closer adherence to the calculated values. through RI is a comhination of the volt- It only seems natural to put the comput- Because of their temperature stability and age -divider current plus the base current. er to work to lessen the drudgery of doing low leakage specilicatiuns, silicon rather The base current is equal to the collec- repetitive mathematical calculations. 'Ihe than germanium transistors are preferable

tor current divided by beta. It is found BASIC program show n in I.isting I is for this type of circuit. from: written to do just that. In addition, it Finally. you've no doubt noticed that serves as a sort of scratch pad for your we have yet to specify a specific transistor. IB = 1.28/100 = 0.0128 mA designs. and allows you to do several That's because for this type of application So the total current through RI is 0.054 what -if" calculations easily. the pro- it really doesn't matter! Almost any n1A - 0.0128 n1A = 0.067 mA. and RI gram was written for a Commodore 64, small -signal device will do tine. R -E

77 Radio- COMMUNICATIONS CORNER ElectronicsEMI& continued Iron) page 31

dl3 greater than the signal received by a single antenna. A special detector samples the signal-to-noise ratio of the received signal on a half -cycle basis. It out -of -phase 4. multipath reception at one antenna causes the signal-to-noise ratio to tall below a minimum value, the PANASONIC CABLE CONVERTERS, detector automatically inserts the Wholesale and Retail. Scientific Atlanta and delay line by opening the elec- Pioneer Cable Converters in stock. Pan- tronic switch, thereby flipping the asonic model 130N 68 channel converter $79.95, Panasonic Amplified Video Control phase of the signal from antenna s Switch Model VCS -1 $59.95. Scientific Atlan- by 180°, which in turn causes the ta Brand new Model #8528 550MHZ 80 delayed signal to add once again Channels Converter $89.95. Video Corrector to that of antenna A. (MACRO, COPYGUARD, DIGITAL) EN- BLUE STAR To avoid switching HANCER $89.95. Write or call constant IND., 4712 AVE. N, Dept 105, Brooklyn, NY hack and forth, which might dis- 11234. Phone 1-718-258-9495. tract the listener, the detector is CIRCLE 85 ON FREE INFORMATION CARD designed so that it maintains the phasing as long as the received signal is strong enough to be usable. NOW Only if new or changing multipath CALL signals degrade the "out of phase" signal to an unacceptable value AND will the detector cause the delay RESERVE line to switch out. Some of you familiar with selec- YOUR SPACE tive fading on the high -frequency 6 x rate $745.00 per each insertion. shortwave hands will wonder what Reaches 242,400 readers. happens to the receiver's volume Fast reader service cycle. level when the signal varies within Short lead time for the placement of ads. the allowed range (before it falls SIMPLY SNAP THE WAT 50 MINIATURE FM TRANSMITTER on top of a 9v battery and We typeset and layout the ad at no low enough to activ lte the delay - hear every sound in an entire house up to 1 additional charge. line switching). The answer is that mile away! Adjustable from 70-130 MHZ. Use nothing happens; there is no with any FM radio. Complete kit $29.95 + Call 516-293-3000 to reserve space. Ask for Arline Fishman. Limited number of in volume level. the $1.50 S E H. Free shipping on 2 or more! COD change On pages available. Mail materials to: frequencies, all signals add $4. Call or send VISA, MC, MO. DECO, shortwave INDUSTRIES, Box 607, Bedford Hills, NY mini -ADS, RADIO -ELECTRONICS, 500- are AM or single sideband (which, 10507. (914) 232-3878. B Bi-County Blvd., Farmingdale, NY a 11735. of course, is only variation of CIRCLE 127 ON FREE INFORMATION CARD AM), so the volume level from the speaker will vary it the signal level breaks away from control of the 117 PRACTICAL AGC (Automatic Gain Control) or ^-r IC PROJECTS YOU CAN BUILD the AVC (Automatic Volume .' r : a,,,.,,.,.w. Control); that's a condition abso- lutely hound to occur during selective fading. But wireless sound equipment - uses FM modulation, whose re- BUILD STEVE CIARCIA'S INTELLIGENT ceived volume level depends on SERIAL EPROM PROGRAMMER. Use r-I deviation, not signal strength. Standalone or with Computer/Terminal; 2645T-117 PRACTICAL IC PROJECTS Only it the signal falls to an almost - Programs Standard or Fast Algorithm YOU CAN BUILD $10.95. Dozens of fully - useless level is there any effect on Mode; Menu Selectable, No Configuration tested, ready -to -build circuits you can put to- Jumpers; Programs All 5V 27XXX gether from readily -available, low cost IC's! an FM signal's volume level, and EPROMs from 2716 to 27512. Includes There are a total of 117 IC circuits ranging the receiver squelch circuits will CMOS and 12.5V Vpp; Read, Copy, Verify from an audio mixer and a signal splitter to a mute the sound long before the after Write; Intel Hex File Upload/Down- tape -deck amplifier and a top -octave gener- listener hears a change in volume load. Full Programmer Kit $199.00, Power ator organ! From TAB Books. To order your level caused by the received signal Supply add $19.00. S&H $5 in USA. CCI, 4 copy send $10.95 plus $2.75 shipping to Park St., Suite 12, Vernon, CT 06066. (203) Electronic Technology Today Inc., P.O. R -E strength. 875-2751. Box 240, Massapequa Park, NY 11762- CIRCLE 196 ON FREE INFORMATION CARD 0240 78 Radio- ElectronicsLUUULi

SIGNA' E UMlhal I..., Mk( EC uen IC i

. .

BUILD STEVE CIARCIA'S NEW VIDEO TUNABLE NOTCH FILTER-for elimination DIGITIZER. True "Frame Grabber". pic TV, of any FM, or VHF signal. Can be tuned takes 1/60th sec Not bus Dependent - precisely to ANY signal within these ranges: THE MODEL WTT-20 IS ONLY THE SIZE OF Standalone digitizer Serial output, trans- 'MODEL 26 -Ch's. 2-6 plus FM (54-108 Mhz] A DIME, yet transmits both sides of a tele- mits 300bps to 57.6Kbps Resolution: 'MODEL 1422 -Ch's. 14(A) -22(I) [120-174 phone conversation to any FM radio with 256 x 244 x 6 w/64 level grayscale Accepts Mhz] 'MODEL 713 -Ch's. 7-13 [174-216 Mhz] crystal clarity. Telephone line powered - never any NTSC video input, B&W or Color Highly selective 60dB notch. Send $30 each. needs a battery! Up to'/ mile range. Adjusta- Optxmal Rec/Display makes Video Tele- Quantity prices as low as $15. Money back ble from 70-130 MHZ. Complete kit $29.95 phone Images can be stored & displayed guarantee. STAR CIRCUITS, P.O. Box 8332, + $1.50 S - H. Free Shipping on 2 or more! on IBM PC. Full Digitizer/Serial Transmitter Pembroke Pines, FL. 33084 COD add $4. Call or send VISA. MC, MO. Kit - $249. Call for other options and specs. DECO INDUSTRIES, Box 607, Bedford CCI, 4 Park St., Suite 12, Vernon, CT 06066. Hills, NY 10507. (914) 232-3878. (203) 875-2751. CIRCLE 94 ON FREE INFORMATION CARD CIRCLE 127 ON FREE INFORMATION CARD CIRCLE 198 ON FREE INFORMATION CARD

111111k i YOUR GUI DA E SYSTEM TO A MORE e, REWARDING so FUTURE A CAREER START FOR THE 21ST CEN- TUFY. Since 1905, National Technical Schools has helped people build NEW 442 SYNE WAVE DECODER WITH LOOKSOUND FM SUNGLASSES. Super successful careers. Enter the 21st VARI SYNC-Replaces the oak N-12 $80.00, durable sunglasses with that great look. Each Century through home study courses in Robotics, Computer S.B. add on decoder $99.00, S.B. Tri-Bi de- one has a state of the art micro FM radio built Technology and Servicing, Microprocessors, coder $100.00, Zenith SSAVI $185.00, 5.8.- right in. Great for jogging, bicycling, boating, Video Technology, Basic S.A. decoder $140.00, Starcom converter sports events, etc. $39.95 plus $3.00 ship- Electronics, Trans- portation Technology, Climate Control Tech- $139.95. Buy a decoder take off $(10.00). ping and handling. Visa, mastercard, and nology or TV and Radio Servicing. For a Guaranteed. (402) 331-4957. Call or write for cod. 1-800-522-2636 for orders. (617) FREE catalog, call 1 -800 your free catalog. Many other 843-1900 for information. CAMEO ENTER- -B -BETTER. Or products & write NTS/INDEPENDENT TRAINING quantity pricing. M.D. ELECTRONICS, 5078 PRISES 'INC. P.O. Box 63 Accord, MA GROUP, 456 West M. L. King Jr. Blvd. L.A., So. 108th #115A, Omaha, NE 68137 02018 CA 90037. CIRCLE 204 ON FREE INFORMATION CARD CIRCLE 89 ON FREE INFORMATION CARD CIRCLE 187 ON FREE INFORMATION CARD

waDMG METAL LOCATORS A TREASURE HUNTER'S PROJECT BOOK s I r ... >r rI

LONG RANGE NIGHT VIEWER. See over 2706T-BUILDING METAL LOCATORS, A ZENITH SSAVI $169; Level II $199. Recon- 300' in total darkness. Facial identification to Tresure Hunter's Projects Book $9.95. ditioned. Surplus Sylvania 4040 Converters- 135'. Developed for industrial & government Build your own high -quality metal detector for DIC, N-12, MLD 1200, new low quantity work. Applications include; animal observa- a fraction of the factory -built cost! The detec- prices. Satellite systems, converters, ampli- tion, security surveillance, video recording, tors described in this unique project guide will fiers, accessories. SSAVI project handbook laser & fiber optic work, IR astronomy micro- locate anything from coins and jewelry to gold 56.50 ppd. Radar speed gun for baseball, scopy & thermal research, document & art and silver-and can be built quickly and easi- car/boat racing, bowling, skiing, etc., from examination. 50W halogen, 200,000 CP IR ly! From TAB Books. Get your copy today. $275. Professional models used by police. source. 12VDC operation. $750 delivered. Send $9.95 plus $1.75 shipping to Elec- Catalog and coupon $1.00. AIS SATELLITE (Dealers Wanted). OCTE ELECTRONICS, tronic Technology Today Inc., P.O. Box INC., P.O. Box 1226-R, Dublin, PA 18917. PO Box 276, Alburg, VT 05440. (514) 240, Massapequa Park, NY 11762-0240. (215) 249-9411. 739-9328. Catalog S1. CIRCLE 81 ON FREE INFORMATION CARD CIRCLE 191 ON FREE INFORMATION CARD 79 R -E ROBOT

continued %>'cnn page (>(1 ROBOT PRESIDENT'S MAIL NEST OFFICE ROOM J LISTING 2

: BOX ( feet ---- ) RERB 25.5 IPS 2DUP (FEET) FORWARD 90 DEGREES RIGHT 2DUP (FEET) FORWARD 90 DEGREES RIGHT 2DUP (FEET) FORWARD 90 DEGREES RIGHT 2DUP (FEET) FORWARD 90 DEGREES RIGHT;

LISTING 3

: MS ( milliseconds ---- )

0 ?DO 33 0 DO LOOP LOOP ;

: SECONDS ( seconds ---- ) T

0 ?DO 1000 MS LOOP ;

: MINUTES ( minutes ---- ) 0 ?DO 60 SECONDS LOOP ; T

40 FEET

FIG. FOR THE LISTING 4 2-MODEL OFFICE EXPERIMENTAL TRIP program that is shown in Listing 5.

: ATTENTION (---- ) BEEP BEEP 1 SECONDS ; LISTING 5

: WARNING (---- ) : TRIP ( ) 5 0 DO BEEP 1 SECONDS LOOP ; WARNING RERB 20 IPS 3 FEET BACKWARD TURN -AROUND 2.5 AHEAD : TURN -AROUND (---- ) TURN -RIGHT 12 AHEAD TURN -LEFT RERB 10 IPS 180 DEGREES 5 AHEAD TURN -LEFT 36 IPS LEFT ; 10 AHEAD TURN -RIGHT 2 COLLECT 7 AHEAD 2 COLLECT 8 AHEAD TURN -LEFT (---- ) TURN -RIGHT 25 AHEAD TURN -RIGHT 90 DEGREES LEFT ; 3 AHEAD 2 COLLECT 11.5 AHEAD 4 COLLECT 11.5 AHEAD TURN -RIGHT : TURN -RIGHT (---- ) ATTENTION 3 COLLECT ( President) 90 DEGREES RIGHT ; 14 AHEAD TURN -LEFT 4.5 AHEAD TURN -RIGHT 12 AHEAD TURN -LEFT : AHEAD ( feet ----) 10 IPS 5.5 AHEAD FEET FORWARD ;

: COLLECT ( minutes ---- )

ATTENTION MINUTES WARNING : word TRII' executes the entire program: it the robot to make several trips during the is shown in Listing 5. day. without having to tell it to do so each TRIP only causes the robot to make one time. We can schedule the trips When de- recharging area and turn around to go excursion around the office. hut y.e want sired using the \cords AM. PM. and forward. hhe word TURN -AROUND WAIT -UNTIL. WAIT -UNTIL simply makes a 1511° turn. the word AI-IEAI) is waits in a delay loop until the current time shorthand for a forward move. COLLECT LISTING 6 is identical to the desired tinte. Ail and combines the Al I ENTION. WAITING, I'll set the desired time. Time is specified and WARNING functions. because we al- : MAILBOT (---- ) in hours. so minutes must he expressed as ways use then' together. The definitions of 8.5 AM WAIT -UNTIL TRIP fractional hours. For example. 8.5 AM is 9.5 AM WAIT -UNTIL TRIP those words are shown in Listing 4. 8:30 ant. The entire MAILBOT program 10.5 AM WAIT -UNTIL TRIP A trip consists of hacking out of the is shown in 6. 11.5 AM WAIT -UNTIL TRIP Listing recharger and exiting the mail roost. mak- 1.5 PM WAIT -UNTIL TRIP NMI can extend RCL to deal with addi- ing a clock isc trip around the office. 2.5 PM WAIT -UNTIL TRIP tional hardware and to provide greater stopping at several points (including a 3.5 PM WAIT -UNTIL TRIP software flexibility. FORT' I gives you the long stop at the president's office). and 4.5 PM WAIT -UNTIL TRIP freedom to experiment and add to the ca- finally returning to the 'nail room. the pabilities of the system. R -E

80 Learn micro -processing with the new sistors R51. R52. R53. and R54. The MICRO -PROFESSOR 1P STEREO RECEIVER VCO frequency is determined by ('43 and rfnuinuetl from page 44 the resistance of R72 and R55. The setting of R72 is adjusted so that the VCO fre- aM! , vD quency. which can be measured at pin 4. 'he 1('s A(iC function was not used in is near 67 kHz. the design. Instead. pin 16 vv as terminated Adjustment of R72 is not critical. and by R40 and (3 3. simply adjusting it titr clearest SCA re- A 10.7 -MI It tuned circuit is formed by ception is adequate. (If 92 kl-Ii operation L7. C38. and C37. Resistor R4 acts as a is desired. R55 should be changed to s\\ resistor to obtain the wide about 6.8k.) Capacitor C-14 is used as a bandwidth of the quadrature circuit. C37. loop titter titr the phase -locked loop. Au- Students, engineers or technicians - C38. and L7. Drive voltage from pin 8. IF dio appears at pin 7 of the I.\i565. A de - upgrade your micro -processing skills out. to pint). quadrature detector input. is emphasis network made up of R56. C45. with the new Micro -Professor IP. delivered via 1,6. The alue of that induc- R57. and C -I6 will suppress an\ 67-k Hi. The MPF-1P features: tor is somewhat critical for proper components and attenuate high -frequency extensive software support squelch -circuit operation. It should he he- noise. more built-in memory tween 18-22 µ1-I. We had an l$ -µH unit An audio-atplitier stage. Q7. brings improved keyboard on hand so it was used. up the detected audio level to about 5(11) larger display A load for the AFC circuit is provided mV. From the amplifier. the signal is sent Three tutorial guides help cover all by R43. arid R42 biases the audio circuit to the selector switch. S2. for routing. capabilities. The ideal training tool! in the IC. Capacitor C38 is used to tune MPF-IP will deliver you into the growing world of micro -processing. Invest the quadrature circuit to 10.7 N1Ht. It is FM decoding now! adjusted for best received audio and zero Audio from Q6 is also sent. via block- Plus -FREE GIFT Only $199.95 DC voltage across R43. ing capacitor C49. to IC3. an LV113ION Che.k this hox (or FREE Recovered Z -RO Microprocessor total modulation is present F\1 -stereo multiplex decoder. The Programming and 1 at pin 6. It contains the FM hasehand and I.M1310N contains a VCO. a phase -lock- Interfacing textbook when you order within 7 days. Dept RE0887 the SCA signal. The hasehand audio is ed loop for regenerating the 38-k Hi. stereo Sih.95 ,tire. tinc!nde 5326 9th Ase. N E. 57.511 postage taken off through and a as a Seattle. WA 98105-3617 R44 C39. subearrier. lock detector used ster- nautili, Kt the hasehand-audio amplifier is built eo -indicator circuit. and a decoder circuit For immediate action call TOLL FREE: around Q6. a 2N3565. It is set up for a for deriving the left and right audio chan- nominal gain of about 5 (the rttio of R44 nels. the internal VC() operates at 76 1-800426-1044 to R46 is the approximate gain of this kHz and the I9 -k Hi and 38-kl-Iz signals Full money back guarantee. WU (d.d i I1suled wilt I.n,ni.tl move: l J stage). Resistors R-15 and R46 bias Q6 to are derived from an internal frequency CIRCLE 111 ON FREE INFORMATION CARD about 6 volts at I milliampere. R47 is a divider. No indicators are required and load resistor. About 2 volts of baseband alignment consists simply of adjusting audio is present at the collector of Q6. R73 titr a 19-k11t signal at pin 10. Audio from Q6 is fed to two separate Getting back to the circuit. C53. R62. LEARN TV/VCR circuits. One circuit is an SCA demod- and C54 form a compensating network for ulator: the other is an F\1 stereo decoder. IC3's internal phase -locked loop. Capaci- REPAIR tor C5O is the loop filter for the phase - No Previous SCA demodulation locked loop. The network made up of Experience Necessary Audio from Q6 is fed to an SCA take- C55. R63. and R73 control the center off R -C high-pass filler made up of C40. frequency of the internal VCO. which R48. R49. C41. C42. and R65. That litter should be 76 The 19-k1lz pilot signal kilt. ti -- substantially attenuates audio compo- (derived from an internal divider) is avail- . f nents below 50 kHz. able at pin IO litr test purposes. Audio 1 he SCA demodulator. IC2. is an output appears at pins 4 (left) and 5 '41 LN1565 phase -locked loop. It contains a (right). Resistors R64 and R65 sere as ' `'-!' 11f-.

VCO ( Voltage Controlled Oscillator) and loads for the internal audio amplifiers. sou can train at home in spare time for a mon- No.es-making career as a TV, VCR Repair Specialist. phase a is detector comparator. If signal of F\1 -audio de -emphasis pro\ ided by No need to quit your job or school. We show you how sufficient amplitude (about 1011 millivolts) C56 and C57. the right and left audio to troubleshoot and repair videocassette recorders and TV sets, how to handle house calls and shop repairs for is led into pin 2 or 3 of that device. and its front pins 4 and 5 is red to S2. aim Mt any make of television or VCR. You learn about is TV receisers, tuners and antennas, x-ray emission, the frequency sufficiently close (say within The audio amplifiers in this circuit. IC-; cha.acteristics of sound, how electrical impulses are con- ±3O1% (to the VCO frequency. the VCO and ICS. are L\1386N's. They each served into a TV picture, and much, much more. Tools are included with your course so you can get "hands-on" will lock to the input frequency and track provide about a (1.5 -watt output. adequate pra. nice as you follow the lessons step bs step. Send for free facts about opportunities in TV'VCR Repair and it: that is. the voltage that controls the Fir driving an eight -ohm speaker. Do not fino out how you can start making money in this VC() will titllow any changes in the fre- use speakers that present less than an great career. Experts show you what to do, how to - quency of the input signal. 'Mc control eight -ohm load. do it...guide you every step of the way! voltage titr the VCO is present at pin 7 and The entire receiver draws about 125 L.er, thing is explained in easy -to -understand language with plenty of drawings, photos and diagrams. But if is a linear function of the input -signal ntilliantp: at 12 -volts (the recommended there is ever any thing in your lessons you don't under- frequency. Therefore. the supply voltage). the supply should be stand, you can write or phone your instructor and you LM565 can can count on getting an authoritative answer. Send for function as an FN1 detector with no exter- regulated and have good filtering. A suit- free facts and color brochure. No cost. No obligation. Nc salesman will visit you. MAIL COUPON TODAY! nal inductive components required. (At able power supply is shown in Fig. 3. the SCA-suhcarrier frequencies of 67 or TICS SCHOOL OF TV/VCR REPAIR, Dept. DE077 s'... .. Scranton Pennsylvania 18515 512 kHz. inductors can beeome rather Next time Please send me free facts on how I can team TV/VCR large and sontevvhat costly. It is therelitre 'That's all the roost we have for now. Repair at home in my spare time. No salesman will visit. to our advantage to eliminate those coils. Next tinte well show you how to build. Name Age and their alignment.) align. and use the receiver. The PC pattern Address the LN1565 is biased by external re- will he presented at that time. R -E City/State/Zip

Phone 1 ) J 81 MARKET CENTER

FOR SALE ATTENTION looking for surplus test equipment signal generator voltmeter oscilloscope. J.B. ELEC- WRITE FOR RESTRICTED technical information: Electronic TRONICS, 9518 Grand, Franklin Park, IL 60131. surveillance, schematics, locksmithing, covert sci- TEST equipment, reconditioned. For sale. $1.25 for ences, hacking, etc. Huge selection. Free bro- catalog. WALTER'S, 2697 Nickel, San Pablo. CA 2!McGEE'S chure MENTOR -Z, 135-53 No. Blvd., Flushing, NY 94806. SPEAKER ELECTRONICS 11354. (415) 724-0587. & CATALOG OLD radio TV TV tunable notch filters, free brochure. D.K. VIDEO, schematics. Send $1.00, make. 1001 BARGAINS IN SPEAKERS model.RADIO MAPS, P.O. Box 791, Box 63/6025, Margate, FL 33063. (305) 752-9202. Union City. CA toll free 1-800.346-2433 for ordering only. 94587. 1901 MCGEE STREET KANSAS CITY, MO. 64108 FREE power supply with Assortment #103 ROBOT! kits. Books and Plans! Learn to build your (February '84 article, has printed circuit, own robots. Free catalogs contain hundreds o' af- TOKO coils(4), 2N3904(2), BF085, 7812, fordable robot systems. Explore the world of WHOLESALE car stereos alarms electronics. Huge robotics today. Catalog: CEARGS-ROBOTS!, POB selection. Catalog $1.00. NORMAN ELEC- 74123, MC1330, 1N914, 1N5231B. TELE - 458, Peterborough, NH 03458. (603) 924-3843. TRONICS, Box 3579A Ridgewood, NY 11386. ASE-MAST ASSORTMENT #301 (October LATEST high-performance op -amps, power BATTERIES rechargable, gel -lead, pure lead Ni - Article) Printed IC's, Circuit with all tran- mosfets. First quality. Send stamped envelope for cads send for free complete listing of batteries by sistors, diodes. Only $25.00/each assort- list. ANZA INSTRUMENT CO., Box 60907, Palo amp hr and voltage. ENERGY CONTROLS, 20451 Alto, CA 94306. Stephens St., Clair MI 48080. ment. Five/$112.50. Shipping $3.00. 1 Shores, (313) 775-3492. (800) 821-5226 Ext. 426. (orders). or write CABLE television converter, descrambler RESISTORS: 1/4 watt, JIM RHODES INC., P.O. Box 3421, Bristol, and wireless remote control video equip- 5%, all standard values to 4.7 meg. 20 pieces of one value $1.00 postpaid. TN 37625. ment accessories catalog free. CABLE DIS- RAHTEC. Box 36064, Minneapolis, MN 55435. TRIBUTORS UNLIMITED, 116- Main Road, DESCRAMBLER catalog all makes. Special com- PCB volume fabrication from Hong Kong INTEG- Washington, AR 71862. bo Jerrold 400 and SB3 $165. New cable de - RITY TECHNOLOGY, 105 Serra Way, #230, scrambler kit $39.00 (assembles in half hour). Send Milpitas, CA 95035-0604. LASERS, components and $1.00. MJ INDUSTRY, Box 531, Bronx, NY 10461. accessories. Free catalog, M.J. NEAL COMPANY, 6672 Mallard Ct., Ori- SURPLUS computers: Multibus. Versabus. S-100, TUBES! 59e. Year guarantee. Free catalog. Tube ent, OH 43146. VME, AMIGA, Atari ST-boards, power supplies, tester S8.95. CORNELL, 4215 University, San Di- test equipment, terminals, disk drives,'complete ego, CA 92105. systems. Free catalog. Trading IBM -compatibles for unwanted systems: buying unwanted equipment. IS it true...Jeeps for $44 through the government? HIGH-TECH SURPLUS, (203) 723-5694, 490 Call for facts! 1 (312) 742-1142, ext. 4673. CB RADIO OWNERS! Wooster Street, Naugatuck, CT 06770. OLDTIME radio programs on high quality tapes. We specialize in a wide variety of technical infor- TAP complete set volumes 1-84 quality copies S1.00 Comedy! Adventure! Music! Free catalog. CARL F. ppd PEI, P.O. Box 463, Mt. NJ mation, parts and for - Laurel, 08054. FROELICH, Heritage Farm, New Freedom, PA services CB radios. 10M FM 17349. conversions, repairs, books. plans, kits. PHOTOFACT folders, under #1400 S3.00. Others high-performance accessories. Our 11th year! $5.00. Postpaid. LOEB, 414 Chestnut Lane, East LINEAR PARTS -transistors: MRF454 $15, Catalog $2. Meadow, NY 11554. MRF455 $12, MRF477 $11, MRF492 $16.75. INTERNA P. . ,;1500R MRF421 $22.50, SRF2072 $13, SRF3662 $25, CBC rw,E33, i LW. E. EQUIPMENT liquidation: Surplus remote -control 3800 $18.75, 2SC2290 $19.75, 2SC2879 $25. PHOENIX. AZ 85045 converters, with touch-type remotes. favorite chan- Tubes: 6KD6 $10.50, 6L06 $9.75, 6LF6 $9.75. nel programmable, digital PLL synthesized, auto- 8950 $16.75. Best prices on Palomar road noise matic fine tuning, switched TV outlet, 30 day mics, Ranger AR3300. New 16 -page catalog listing warranty, $35.00. Quantity package 25+ units radio/amplifier tricks -channel modification, PLL- SUPERFAST morse code supereasy. Subliminal S15.0010. field run, as is (includes service manual). sliders, peaking for range, hard -to -find linear cassette. $10.00 Learn Morse Code in 1 hour; amaz- Oak minicode N12 decoders quantity package 25+ parts-mail $1.00 to: RFPC, Box 700, San Marcos, ing new supereasy technique $10. Both $17. units $20.00(v, field run. as is. "Beeping", notch Moneyback guarantee. Free catalog: SASE. CA 92069. For same day parts shipment, call (619) filter CH3 decoders. 30 -day warranty, $15.000 , 744-0728. BAHR, 2549-E3 Temple. Palmbay. FL 32905. quantity 25+ $10.00(r, field run, as is. shipped prepaid. All TUBES. new. unused. Send self-addressed. stamp- others add $3.00 unit shipping. Send money ed envelope for list. FALA ELECTRONICS, Box order to ELECTRONICS PRESS, PO Box 10009, 1376-2, Milwaukee, WI 53201. Colorado Springs, CO 80932. TUBES - 2000 TYPES TUBES: "Oldest", "latest". Parts and schematics. DISCOUNT PRICES! SASE for list. STEINMETZ, 7519 Maplewood Ave . RE Hammond, IN 46324. Early, hard -to -find, and modern tubes. Also transformers, capacitors and CABLE -TV converters and descramblers. Low Quality Microwave TV Antennas parts for tube equipment. Send $2.00 prices, quality merchandise, we ship C.O.D Send r ,a.T Super High Gain System 599 95 ' shipping) /or 20 page wholesale catalog. $2.00 for catalog. CABLETRONICS UNLIMITED, a AMR High Gain 1 P.O. Box 266, South Weymouth, MA 02190 (617) System S79 951 shipping) Multi -Channel 1 9 ANTIQUE ELECTRONIC SUPPLY 843-5191. to 2 7 GHt 688 W. First St. Tempe, AZ 85281.602/894-9503 Dealerships. Oty. Pricing. Replacement Parts Upgrade CD players, other equipment with Au- Phillips -Tech Electronics dio Amateur, world's only audio construction PO Box 8533 Scottsdale, Al 85252 $18/year; . quarterly. $30/two. Satisfaction guar= (602) 947-7700 1300 Credit all phone orders!' CABLE TV converters. Scientific Atlanta, Jerrold, LIFETIME anteed. MC/VISA (603) 924-9464; checks to Box WARRANTY MasterCard Visa C00's Oak, Zenith, Hamlin. Many others. "New" Video 576, Dept. En, Peterborough, NH 03458-0576. Hopper "The copy killer." VHS -wireless remote $239.00. Visa, M/C & Amex accepted. Toll free ZENITH SSAVI, ready to go $100.00 plus shipping, 1-(800) 826-7623. B&B INC., 10517 Upton Circle. order C.O.D. 1 (305) 752-9202. Bloomington, MN 55431. FREE sample! Discover Apex screwdriving bits, ac- TI -99/4A software hardware bargins. Hard to find BUILD your own pro monitors 32 pg. 5 part man- cessories. Sensational fit, remarkable toughness, items. Huge selection. Fast service. Free catalog. ual discloses design criteria utilized by major man- amazing durability. Write today! R. SHOCKEY'S, DYNA, Box 690. Hicksville, NY 11801. ufacturers of pro monitoring systems. Blueprints 5841 Longford, Dayton, OH 45424. included! $25.00 complete to: BRIX ENTER- Z -TAC Zenith cable unit only $175.00. Buy 5 at only DECODE nearly any Gated Pulse signal with our 10 $125.00. PRISES INC., 2419 Richmond Road, S.I.N.Y. $150.00. or at only These units do not new super simple circuit. Works on In -band, AM or we 10306. use block convertors, install our own VHF tuner FM pilot tone-use with Hamlin, Jerrold, Sylvania. for excellant picture quality. UPS daily. COD accept- SCANNING disk television. Read all about it! "The Complete plans and theory only $13.50 plus $1.50 ed. All orders shipped 2nd day air. 90 day warranty Mechanics of Television." (1987) 182 pages $20.00 P&H. ELEPHANT ELECTRONICS INC., Box on units. Call for information or free catalog or write postpaid. TESLA ELECTRONICS, 835 Bricken, 41865-J, Phoenix, AZ 85080. (602) 581-1973. AMCOM, P.O. Box 68391, Virginia Beach, VA Warson Woods, MO 63122. VIDEO scrambling techniques, the original "secret 23455. Phone: (804) 456-5505. LEADER LFC-945 signal level meter $425.00. (312) manual" covers Sinewave, Gatedpulse, and SSAVI FREE "National Semi Conductor" pocket cal- 771-4661. systems. 56 pages of solid, useful, legible informa- culator and catalog of car stereo, C. s, radar detection. only $14.95 ELEPHANT ELECTRONICS tors, alarms, accessories. Dirt cheap! Send $4.00 TUBES, name brands, new. 80% off list, KIRBY, INC., Box 41865-J, Phoenix, AZ 85080. (602) for postage and handling, ELECTROMANIA, 51B 298 West Carmel Drive, Carmel. IN 46032 581-1973. Sunrise Highway, Lynbrook, NY 11563.

82 DO YOU ROL' GET THE BEST BUY FROM THE ? et s face it: There will always be some outfit that can undercut a published price. They do it by flaying no overhead, and no responsibility to you, the consumer. "So, you want that Jerrold 450 combo? The one that Pacific Cattle Co.. Inc., is offering for $19900? /I Well, that's a good price, but Maim here'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 543700 on the phone bill! No, I don't know about any guarantees on your Gerald, who's that? Listen, if you see that creep..." etc. At Pacific Genie Co., you've got an established company who will be here for you, time after time. We may be tough competitors, but we've a soft got spot for our clients! Try us, and be treated right -and we'll prove it by giving a one-year warranty on everything we sell. Check our prices on Scientific Atlanta Unitsi

1 10 OR ITEM ITEM 1 10 OR UNIT MORE UNIT MORE RCA 36 Channel Converter (Ch.3 output only) 29.00 18.00 Minicode (N-12) with Van Sync 99.00 62.00 Panasonic (our Wireless Converter best buy) 88.00 69.00 Minicode VariSync with Auto On -Off 145.00 105.00 400 or 450 Converter (manual fine tune) 88.00 69.00 Econocode (minicode substitute) 79.00 52.00 'Jerrold 400 Combo 169.00 119.00 Econocode with VariSync 89.00 56.00 Jerrold 400 Hand Remote Control 29.00 18.00 MLD- 1200.3(Ch.3 output) 99.00 58.00 Jerrold SB-Add-On 89.00 58.00 MLD-1200-2 (Ch.2 output) 99.00 58.00 *Jerrold SB-Add-On with Trimode 99.00 70.00 'Zenith SSAVI Cable Ready 175.00 125.00 *M-35 B Combo unit (Ch 3 output only) 99.00 70.00 Interference Filters (Ch.3 only) 24.00 14.00 M-35 B Combo unit with VariSync 109.00 75.00 Eagle PD -3 Descrambler (Ch.3 output only) 119.00 65.00 Minicode (N-12) 89.04) 58.00 `Scientific Atlanta Add-on Replacement Descrambler 119.00 75.00

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

VISA SUBTOTAL California Penal Code #593-D forbids us from Shipping Add shipping any cable descrambling unit to anyone 3300 per unit residing in the state of California. COD 8 Credit Prices subject to change without notice Cards-Add 5% Pacific Cable Co., Inc. PLEASE PRINT TOTAL 7325/ Reseda Blvd., Dept. R-08 Name Reseda, CA 91335 Address City (818) 716-5914 (818) 716-5140 State Zip Phone Number ( Cashier's Check O Money Order C.O.D. O Visa O Mastercard NO COLLECT CALLS! Acct. Eap Date IMPORTANT When please ordering, 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 penury *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 registered trademark d General Instruments Cap Dated: Signed

83 Cable TV Converters SUPER Octopus circuit tester; plans and user's CABLE -TV DESCRAMBLERS. You name it! Why Pay A High Monthly Fee? guide; $5.00 to VIEWPOINT, 8405 Glencrest, Sun You'll get it! Specializing in hard to find Valley, CA 91352. Products include ew Jerrold equipment. Special: Scientific Atlanta com- Jerrold ' ELIMINATE light and dark from copying new video bination with remote S229. C.O.D. any- Trj-Mode," SB-3, Hamlin, Oak VN-12, tapes. Schematic $5.95 circuit board $5.00. BLED- SOE, PO Box 3892, Central Point, OR 97502. where. (916) 541-8461. NATIONAL CABLE/ M -35-B, Zenith, Magnavox, Scientific SO. SHORE INC., 1512 Roswell Road # 229, Atlanta, and more. (Quantity dis- DETECTIVES, experimenters. Exciting new plans. Hard to find micro and restricted devices. Large Marietta, Georgia 30067 counts) 60 day warranty. For fast ser- catalog $5.00 refundable on 1st order. WILSON, vice C.O.D. orders accepted. Send P.O. Box 5264, Augusta, GA 30906. PLANS AND KITS SASE (60 cents postage) or call for info ELECTRONICS surveillance book on eavesdrop- (312) 658-5320. Midwest Electronics, ping investigation surveillance includes civil liberties BUILD this five -digit panel meter and square -wave outlined by congress (Office of Technology Assess- generator including an ohms, capacitance and fre- Inc.!, HIGGINS ELECTRONICS, 5143-R ment). Also covers infrasonic sound (sound below quency meter. Detailed instructions $2.50. BAG - W. Diversey, Chicago, IL 60639. MC/ hearing) send $17.00 to: COUNTERMEASURES, NA LL ELECTRONICS, 179 May, Fairfield. CT P.O. Box 1021, Rowlett, TX 75088. 06430. Visa orders accepted. No Illinois orders Mon. -Fri. -9 A.M.-6 P.M.CST RADIO, free power, modern day crystal set. Send for HI -Fl speaker systems, kits and speaker compo- accepted. info. MERIDIAN SYSTEMS, Box 116, Eliot, ME nents from the world's finest manufacturers. For be- 03903. ginners and audiophiles. Free literature. A&S SPEAKERS, Box 7462, Denver, CO 80207. (303) WIRELESS remote cable converters $60.00 with ULTRASONIC ranging system measures dis- 399-8609. purchase of selected video kit. $50.00 boards and tances from 6" to 35'. I/O is TTL compatible, can be parts for video and hobby projects from connected directly to most computers. Experi- VOICE disguisers! FM bugs! SWL active antenna! magazires kit $40.00. Video menter's kit includes one SN28827 ranging module, Receivers! Morel Catalog $1.00 (Refundable): and other sources. SA turn on write list one Polaroid 50KHz electrostatic transducer, and XANDI ELECTRONICS, Box 25647, Dept. 60P, dechipher kit $75.00. Call or for and details. WIZARD, 1-(419) 24 East user's manual with data sheets. Great for alarms, Tempe, AZ 85282. 243-7856. Central, Toledo, OH 43608. computer mapping, robotics, etc. $59.95 s $2.00 PROJECTION TV...Convert your TV to project 7 postage. $2.50 for COD. I.O. MICRODEVICES, gated pulse theory. Twelve information - foot picture. Results comparable to $2,500 proj- JERROLD P.O. Box 2386, Canoga Park, CA 91306. (818) ectors...Total cost less than $30.00 plans and 8" packed pages covering DI & DIC converter opera- 348-8312. tion. Includes introduction to trimode $6.95 lens $21.95...Illustrated information FREE...MAC- system. ROCOMA-GL, Washington Crossing, PA 18977. plus $1.50 postage and handling. ELEPHANT INC., 41865-J, Phoenix, AZ Creditcard orders 24hrs. (215) 736-3979. ELECTRONICS Box 581-1973. 85080. (602) PAY TV AND SATELLITE DESCRAMBLING CRYSTAL radio sets, plans, parts. kits, catalog NOW 120 PAGES $1.00. MIDCO, 660 North Dixie Highway, Hol- DESCRAMBLE the latest video cassette copy -pro- line theory. bypasses 13 cab e ' satebte systems nclud no Atter lywood, FL 33020. tection scheme. Our simple zapper circuit takes Schematics, the jitter out of your picture. Complete plans and Dark Video St4 95 6 Ed Update Omt 59 95 [,penmerd', Wah Vid. muskeleennq data $12 95 N hobby/broadcasting/1750 meters/ham/ theory only $13.95 plus $1.50 postage and handling. egc.pner Latest Circuits cloning. Cable CATALOG: Two-way security systems design 512 95 MSS MMDS HaidbgOk rot CB: transmitters, antennas, scramblers, bugging PC board and complete kits also available. ELE- microwave hackers 59 95 Build Satellite SvslemS Under $605 $12 95 devices, more! PANAXIS, Box 130-F8, Paradise, PHANT ELECTRONICS INC., Box 41865-J, Phoe- Any 3 526 Summer catalog S1 nix, CA 95967. AZ 85080. (602) 581-1973. Shojiki Electronics Corp. 1327A Niagara St.. FREE catalog 99 -cent kits -audio, video, TV, MINIATURE electronics devices, like James Niagara Falls, NY 14303. COD's 716.284.2163 computer parts. ALLKIT, 434 W. 4th St., West Islip, Bond's. Catalog $2.00. F&P ENTERPRISES, Box NY 11795. 51272, Palo Alto, CA 94303-L. STRANGE stuff. Plans, kits, new items. Build satel- //EParts lite dish $69.00. Descramblers, bugs, adult toys. HARDWARE AND ELECTRONICS Informational photo package $3.00 refundable. DI- xpress RIJO CORPORATION, Box 212, Lowell, NC 28098. PAC-TEC enclosure specified in Feb.'87 R -E article COPPER CLAD RS -232 DATA SWITCH on Tri-Mode. Pre-drilled..524.95 plus $2.50 S&H. PC VISA/MASTERCARD accepted. Call (617) 339-1026 or send to THE HOBBY HELPER, P.O. 11 n Box 308, Bridgewater, MA. 02324. 10 Whei someone )ur family ULTRASONIC pest repeller: Exceptional design! gel s cancer, Complete quality kit $25.00, assembled $30.00. MAGNIFIER LAMP Cl /eryone UFO DETECTING BOOK: Electronic projects, the- 4' 0.opter magnity,n9 lens (NY 17.5%). UFONICS, 1 pos,ton, rotary type Fully ories, schematics, $6.00 Uses op to a 60 wan bulb (not 9' r e" Double Soled in yi wr family ,nCludedl UL listed. 117VAC 0055-300 5150 sn,eldeo, FCC approved 7 Box 1847-R, W. Babylon, NY 11704. Double Sided $395 ne eds help. 4130-010 IC, sheet 450-010 52695 .055-320 $2795 MELODY Piezo element and application only S3.00. BELL CERAMIC INDUSTRIES, INC., 31 Passmore Avenue, Unit 28, Toronto, Ontario, PIONEER HORN TOROIDIAL Canada M1V4T9. TWEETER TRANSFORMER DESCRAMBLING, New secret manual. Build your own descramblers for Cable and Subscription TV. L Instructions, schematics for SSAVI, gated sync, F:54 ( In Nob.:Nobt knows hewer than sinewave. (HBO, Cinemax, Showtime, etc.) $8.95 J we dr, how mul h help anal + $1.00 postage. Catalog $1.00. CABLETRONICS, 12- PIONEER WOOFER understanddrng a nm Thar s Frequency response MO to ded Box 30502R, Bethesda. MD 20814. 15,0001-11 Power nandl,ng Capebat Power 65W RMS 11 of magnet why a,ur oc vier and rehahllit.ulnn des 35W RMS. resonant frequency 25 to 2500 Hf response l's 120.011 primary. 2 200, 5A pro tffran t c mphasiie the whole SATELLITE descrambling manual, Video Cypher 4 lbs 2 kHz 3'A" a 3'n` voice coil seconder.es 4'e" round family, n, tI lust the canter parent II. Schematics, thorough explanation of digital audio $995 Amon'Amon regular services 4270.050 36m $590 rem-too s1550 $1395 .120-150 12fO we ' information and encoding, EPROM code, DES. (HBO, Cinemax, net Ito," 1.31 ,4 01 nai 11,1,91 pnlvlak guidance to 3 patients and families. Showtime.) $10.95 + $1.00 postage. Catalog $1.00 tr0nspur paliento to and from CABLETRONICS, Box 30502R, Bethesda, MD 300 PIECE CAPACITOR/" treat supply home Care items 20814. KIT assist parents in then return FREE CATALOG to v ryda v life Ede is hat cuncert us CABLE television converter,.descrambler, MI all see we Ire even Our new 56 page catalog contains ~' >' control video equip- C ma ire dun I he research urwam and wireless remote thousands of items that you need r -c auon we a re sat well known to he 4 r-- free. CABLE DIS- everydayY for do-it-yourselfY pout monment or dmerent ment accessories catalog . No 1251 laces canter mona' protects. DrotlUCt engineering, v toes end wonng voneges TRIBUTORS UNLIMITED, 116-P Main Road, electronics repair and more. Call us ( Includes electrolytes. ceram,a. %C TOM end mole' today for your free copy and start d.. Washington, AR 71862. saving! 020420 $495

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84 NEWII INSTALLATION REPAIR SATELLITE TV and 1111 of V1dcoCiphere 2000 and 2100 NUTS & VOLTS CABLE TV Secrets outlaw the M w O A Z 1 N E 71Nk-775 -the publication ca- The Only VCR Instructional Video Program ble companies tried to ban. HBO, Movie Channel. Demonstrating SW YOURSELF* WEAK -A PRICE SNEAK( NUM VOLTZ WILL SSio You MONEY Showtime, descramblers, converters, etc. Sup- Normal & Special Installation Settin9'Externai PARTS pliers list included $8.95. CABLE FACTS. Box 711- Contras Preforming Internal Adjustments ON ELECTRONIC a EOUIPMENT 5810W YOU WHERE TO ANO UNIOUC, R, Pataskala, OH 43062. Dete-ming end Repairing Common Board NE Problema Replacing Pats Covered by Epoxy UNYNEAL AND HAII -TO-FIND ETEAM. SATELLITE TV receiver kits! Instructions! Sche- Static Precautions & Special Soldeng Techniques SUBSCRIBE TODAY! Cr matics! Catalog $1.00 (refundable): XANDI ELEC- Using ROTEC; the electronic test devce for A NTtionel publiafion Fr The Lying And Selling 07Elenron& Eguipmenr TRONICS, Box 25647, Dept. 21S, Tempe, AZ the pofesslonal TYRO dealer 85282. Everything you've wanted to know shown for the first time, for only $59.95 DESCRAMBLER build our low cost satellite TV Vat.< oho sart7.9or 'trots rnstrumew+cow&.on BUSINESS OPPORTUNITIES video only descrambler for all major movies and SNpp.n9 14 50 Send Chef. a add 14 50 COD (Cash, cerhted check a MC On COO NO teen Cod. turns PO1 NY add "tea MECHANICALLY sports. Uses all Radio Shack parts. Order P.C. inclined individuals desiring TRVO dealers receive 310 CO rebate towards 1st ownership board and instructions by sending cheque, money of small electronics manufacturing busi- purchase of ROTEC plus discounts worth more than ness -without investment. Write: BUSINESSES, order, or Visa for S35.00 U.S. funds to: VALLEY $50.00 on soldering equipment and accessories. 92-P.., Brighton 11th, Brooklyn, NY 11235. MICROWAVE ELECTRONICS, Bear River, Nova TESTRON, Inc., Scotia, Canada, BOS-1BO. (902) 467-3577. dept RI 184 Jericho Turnpike, Floral Pak, N Y 11')01 PROJECTION TV...Make $S$'s assembling proj- 800 94, 1000 etl 301 34 Ns -7 days (m NY) 516 358 8014 ectos...easy...results comparable to $2,500 proj- ectors. Total cost less than $30.00. PLANS, 8" LENS and dealers information $20.50. Illustrated Multi Channel Micrówave T.V Receivers VIDEOCIPHER data disk. Apple II and PC. dial information free. MACROCOMA-GLX, Washington 19 2 7 GHt Parabolic Dish car dB Gain (011)(52) (451)42268 (Mexico). 4-10 PM. CST. for Crossing, PA 18977. Creditcard orders 24hrs. (215) LIFETIME WARRANTY information. 736-2880. Complete System 589 95 (Shipping Inc' I Replacement Components SCIENTIFIC Atlantia cable users series 8500 8550 & Expelt Repairs Available get all channels instructions for simple modification BIG ELECTRONIC N & S Call now 'or same ELECTRONICS costs under $10.00 to make. Complete instructions. ,'ROFITS ASSEMBLY BUSINESS P.O. BOX 34522 day shipping! Send no PHOENIX. AZ 85067 16021 230 0640 $10.00 checks to K.F. SPECIALTIES, P.O. Box 443, Fcrked River, S'art home spare time Investment knowledge VISA/MC/COD For Dealer Rates Call 602-888-4080 NJ 08731. or experience unnecessary BIG DEMAND assem- SATELLITE systems $295 up. VISA MC available. blng electronic devices Sales handled by profes- Catalog $2. STARLINK INC., 2603- 6E Artie. sonals Unusual business opportunity Hunstville, AL 35805. SATELLITE TV equipment. Buyers guide. discount FREE: Complete illustrated literature BARTA. RE -0 Bi ' ¿ tO prices. $3.00 N.E.C.S. INC., Box 22808-R1, Little 10ft Satellite system, remote controlled, tracker Rock, AR 72221. Walnut Creek Cali' 93'4 and descrambler with 1 yr free subscription to 20

channels. $1,495 plus UPS. VISTA VISION, 1 (602) SATELLITE scramble newsletter, non-profit pub- HOME assembly. Assemble PC boards for video 458-5482 after 10 a.m. lication, descrambler sources, $1.00, MICHAEL accessories. We supply materials. No experience THOMPSON, Box 4508. Dieppe. Canada. needed, $7.50 per hour. Send self-addressed E1A-6G1. stamped envelope, to: MICRON -ELECTRONICS, PRINTED CIRCUIT BOARDS Boa 4716. Akron OH 44310. 59 degree brand name LNA's! LNB's! Ku -Band LNB's! Discount pricing! Catalog $1.00 (refundable): CIRCUIT boards prepared from layouts or CAD EASY, lucrative. One man CRT rebuilding machin- LNA-RE, 201 E. Southern. Suite 100. Tempe, AZ files. Call for price list (301) 987-4023. PEL, 1205 ery Free info: (815) 459-0666 CRT, 1909 Louise, 85282. Generals Highway, Crownsville, MD 21032. Crystalake, IL 60014.

GREAT VALUES FAST SHIPPING QUANTITY DISCOUNTS 100 MULTIFUNCTIONAL LED D.P.M.SM 4310-15V 2A REGULATED TR INFRARED REMOTE CONTROL UNIT DC POWER SUPPLY TY-41 MKV fog c EssENriAt As U frig e&o Be MEASUREMENT RANGE 1 TO DC VOLTAGE ImV 1000V Kn 259 50 EEÑS OH AC VOLTAGE 10V 100os 4u with tested 569 50 ArEURS DIGITAL TI/ERMOMETER (PC - 00°C Et-ecTR,cal 01.I/0yoow.I DC CURRENT 1 uA - 2A OutW- voltage ,s adruslable Porn 0.155 DC two current hm,t up CAPACITOR METER 1 pF 2 uF K 23000 ange Pe available for selection 20pn,A or 2A DIMENSIONS 3 3 4" . 1 7/8" 4 A,,ombled wit" 1/16" le.tes 536 W An eaoorated prorectron system ,s Wec.ally ce.,gned. '88' sound and 80W+80W DC LOW TIM PRE -MAIN AMPLIFIER . ''''''''''''''''"""-"`""`"'"--"--High stability and relmD,hty rs ulted by emplOgmg hqh au+"ty F,QEE 800 vol age IC 1I RIT 530 E''I Kintp iemeterdmakes the readm9 of vols.,. and current more clearly ; r, 51411,12 ,,hT.,r.d 145 -¡r ~ /I 'k - ndarsurte', cAt4cof ,Nr* (`.OI --/' .. A refr-led case, meat and all ere enclosed lot both and I J T assembled form I a most alleacc acs ry e amateur PPOFESSIONAL 20 STEPS BAR/DOT AUDIO LEVEL COLOR LIGHT KIT f6518 DISPLAY KIT TY45 METAL CABINET X'FORMER 52651680 CONTROLLER r.tiagA SUPERIOR ELECTRONIC SM-328 ROULETTE PEa TURFS

Th,s new desgoed audio level diplay unit n °sung a new 6BOK ntepated torivis Nom National Sem,eondoctor to dove fiOARDe 090 2 R SYSTEM 35,,NDEeOFE55 OENI COEORT 100095, Co :dal( 20 paces of color LEDs (green. yellow and red) on each GROUPS O[EINOEPE,y ENDENTINPUySiG fONTROI CHASER SySEM channel It pov ides two types of dnpay methodh for 6 D[ ECIAI Aa/TOM4TrryoDIMMER CONTROAOIUSTMEhi e EOUR selection bar or 'dot' The d,splay range n from 5748 to Cr4S SING g L 5 SPEED OdB R,f n good for any a,npl,her From 2 watts ro 20099 CN451NGI COMtlOnrIpSTLM FOUR :OhTq OL Ef[EGRAMB / kINpS , Power DC for SU 328 suppry redone, 12VAC or Sc,, ureat gusto taros 1.9"r AND adven conrrp `ORwARD CR,vnRROpGRAM cars as well. 0,t comes won p,nted eircu,t board, all LED N sgnsn B CN4SING 9 r o ea°,op,,, oleo tron.c , omponenrs. wnehes and .,lk screen printed nn n reto, . Uu0 p,ofesk,onalf ont panel Kn 134 95 it is p-"gr, ene1 ,ng TA -2500 m td;'9.9nnn9erdNtr`p6oardp.ogrm t d nW are us mg teasrig HIGH QUALITY ..,, ' ay,oup, g u` Iwo n4i of I n'n9ny ow eat order to ellw,i and w ual moult the b, PRE -AMPLIFIER 8 (sequence bseparated dPd,s,ed Wc f'uitne.mn or 're independent dn hap, m WITH 10 BAND '9!'tliu,tmnr upo,hon.,.N"n tng,` e a ecomk,nd.,w^'pm Pan r asn9 n o. teasngr k EQUALIZER D'^'4n,'omut F^4a"m;tap ,pK.l TERMS SfO mot order 520 min charge card order Chef money onto, or IKoonla 5/ .8 I n AR ..m t5/16".3J 16. phone order accepted We ship UPS Ground Add 10 of total o,de, Im,n --,rem-.trm-sern..mw,--. _ -S 52 501 for shipping. outade USA add 209. Im,n 55001 CA ..,dents add 3l5o0o merenar.dne Pbces OFFICE HOURS: sales tea All sublect to prior sate are subject to change ON without notde Any goods proved to be defective. MUST BE RETURNED A PACIFIC TIME) LY IN ORIGINAL FORM WITH A COPY OF YOUR INVOICE WITHIN 30 11:1-1:.lº, r DAYS FOR REPLACEMENT MON.-FRI. 9:30 to 5:00. SAT. 10:00 to 5:00 1-800-423-3483 INFORMATION: 1-818-282-1196 MARK V ELECTRONICS INC.. MAIL ORDER: P.O.BOX 6610 248 EAST MAIN STREET, SUITE 100. TOLL FREE ALHAMBRA. CA 91801. .®Only for orders paid by Master or Vlsacard ALHAMBRA, TELEX: MARK 3716914 5. IN CAL.: 1 -800 -521 -MARK CA91802

CIRCLE 93 ON FREE INFORMATION CARD 85 YOUR own radio station! AM, FM, cable. Licensed or unlicensed. BROADCASTING, Box 130-F8, Par- - A SINGER'S DREAM! I VIDEO TAPE adise, CA 95967. c p e I COPYGUARD PERSONAL computer owners can earn $1000 to $5000 monthly offering simple services part time. Eliminate the latest copyguard problems Free list of 100 services. Write: C.I.L.G.B., P.O. Box 60369, San Diego, CA 92106-8369. units from $5995 to $16995 EARN thousands with your own electronics busi- Deluxe EÍeetronics (714)998 -6866 ness. I do. Free proof, information. INDUSTRY, Box 1432 7(a'm'Wj., Ca. 531, Bronx, NY 10461. Oran" 92665 FLORIDA business for sale. Electronic service DO IT YOURSELF TV REPAIRS sales. FLORI-DAY ELECTRONICS, 44 Avenue E. REMOVES VOCALS FROM RECORDS! Apalachicola, FL 32320. (904) 653-9657. Now You can sing with the world's best bands! NEW...REPAIR ANY TV...EASY. Anyone can do it. The Thompson Vocal Eliminator can remove Write RESEARCH, Rt. 3, Box 601R, Colville, WA MAKE $$$ manufacturing electronic products! 30 + most or virtually all of a lead vocal from a standardl 99114. plans $5.00 complete! (Free details available) NRG stereo record and leave the background! INC., 11580 Oakhurst Rd., Largo, FL 33544. Write or call for a free brochure and demo record. CABLE TV TURN-ON'S LT Dept. P.O. Sound. R-1, Box 338, "TURN -ON" boards for all models Jerrold 450's. EDUCATION & INSTRUCTION Stone Mountain, GA 30086 1404)493-1258 Requires no internal modification or soldering, sim- F.C.C. Commercial General Radiotelephone li- ply plugs into existing connector. Fully guaranteed. cense. Electronics home study. Fast, inexpensive! INVENTIONS, ideas, new products wanted! Indus- Quantity discounts available. Call or write for infor- "Free" details. COMMAND, D-176, Box 2223, San try presentation/national exposition. Call free mation and prices. VIDEO SOLUTIONS, 3938 E. Francisco, CA 94126. 1-(800) 528-6050. Canada, 1-(800) 528-6060. Grant. Suite 257, Tucson, AZ 85712. (602) X831. 323-6072. CASSETTE recorded home study for new General Class FCC license examinations. Seminars in Phil- WANTED surplus inventories of ICs, transistors etc. CONSULTING SERVICES adelphia, Detroit, Boston, Washington. BOB No quantity too small or large. Call WESTERN JOHNSON TELECOMMUNICATIONS, 1201 Ninth, TECHNOLOGY, (303) 444-4403. FAX (303) DIGITEK turns your ideas into hardware. Design Manhattan Beach, CA 90266. (213) 379-4461. 444-4473. and or prototyping. Send SASE for free feasibility and cost analysis. No job too small. DIGITEK, Box DESCRAMBLER MODULE NOTCH FILERTS 195 Levittown, PA 19059. (215) 949-2260.

COMPLETE cable -TV decoder in a mini -module. NOTCH fillers for any channel. Send $15.00 for COMPUTERS sample unit. Specify output channel of converter. Latest technology upgrade for Jerrold SB-3 or Ra- TANDY computers! MSDOS. IBM. compatible. Dis- dio -Electronics Feb. 1984 protect. Available at very - Money back guarantee. DB ELECTRONICS, P.O. count prices! For quote purchase 1 -800 - Box 8644. Pembroke Pines, FL 33084. or call -36 low cost. For literature, SOUTHTECH DISTRIBUT- SHACK. EDGEWOOD COMPUTER CENTER. ING. 1-(800)-821-5226 ext. 130. SCIENTIFIC ATLANTA & SB-3 CABLE TV DESCRAMBLERS WANTED CABLE SCIENTIFIC Atlanta cable converters (original television converter, descrambler INVENTORS! AIM wants -ideas, inventions, new units), models -8500 and 8550, remote con- and wireless remote control video equip- products, improvements on existing products. We trol...$240.00. SB-3's...$74.00. TRi-Bi's...$95.00. ment accessories catalog tree. CABLE DIS- present ideas to manufacturers. Confidentiality SBSA-3's...$99.00. Zenith (Tag-ons)...5159.00. guaranteed. Call toll free 1-(800) 225-5800 for infor- Jerrold -450 converters...$95.00. Dealer discount TRIBUTORS UNLIMITED,116-C Main Road, mation kit. on units. Call-N,A,S., (213) 631-3552. Washington, AR 71862.

V205 RAM's 1095 CPU's& CHIPS TRANSISTOR SPECIAL SCR., TRIAC', 25 14585 !q 74S SERIES RCA. HC 2500 60 WATTS 020 B la 95 8086 800 2016 1 SO SA 64 35A 1511, PAS IA 104 254 29 74586 35 1 50 17152650 250 8088 160 21102-3 70 I1318NPN5 10220 5 40 SOLID STATE HV BR' D 534.95 100 :5 40 1 40 Ino 35 60 I 40 29 74589 710 145414 75 2804 CPU , 75 8155 2 2 75 21014 4 1 50 TIP 328PNPS TO 220 S 40 200 0 50 I Bo 200 SO &I 19r1 ' 451, 10 /4511' 50 051 /5 15 LINEAR AND AUDIO AMP 2806 CPU l 75 8212 900 21114 1 75 P 34 PNP S. S 95 400 60 70 1 50 9 00 400 10 I Op '45uS 29 741114 50 745181 4710 BAND 01014 5111'1 1804 CTC 195 8703 1600 21121 195 TIP 111 S 50 600 0 1 00 100 1200 600100120 +60 4508 35 5124 2 20 745182 7 00 6004115 '794 1UTPUi 2804 OMIT 5 25 8212 1 45 21142 100 TIP 171NPN U. 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' ,1VUF011r RMNNE 1137UER SINUS 2 7674 11014 04141110 fEA1U01N1. ADD 1 16014515l,345 RATES 5% FOR ORDERS BETWEEN 57500 AND 65000 MINIMU m TELEPOONE C 0 D 10C0ASE ORDER N0 CIIA01rE 52000 6 111111 095 ADD 3% FOR ORDERS ABOVE 550 00 611519051 MAIL 0917E71 55 00 145 6.415011E 51 CA4B010GE, 9A55 02139

TEL (617) 547-7053 WE SHIP OVER 95% fSOLID STATE SALES FAX 617.354-1411 OF OUR ORDERS WITHIN P.O. BOX 74 D - SOMERVILLE, MASS. 02143 TOLL FREE 1-800.343'5230 24 HOURS OF RECEIPT FOR ORDERS ONLY CIRCLE 74 ON FREE INFORMATION CARD 86 OW im my im ~ my my my /111~ m Im IL ~I 1 AK,1-800-344-4539 Puerto Rico 218-61114674 TWX 9103508987 C O --- Tides -622277914 FAX 216-601-33SO - DIGI KEY CORP R P O R ATION - -

il NATIONAL SEMICONDUCTOR PANASON )10DES DIAMOND TOOL UNGAR vrsA " OK MACHINE EWC INC. INTERSIL AD 256K (262,144 x 1) DRAM 15ONS $5.7011; $39.9619 ES CW INDUSTRIES AMDEK 0.E. EAC, INC. J. W. MILLER AAVID ENGINE! 4CAR YAGEO J. W. MILLER LUXO E. F. JOHNSON ATLANTIC SEMICONDUC Factory Firsts "iC CHEMICALS ARIES PLESSEY

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To ON .010101 add Me non arcounure tree, Thee WO ...woo. SERVICE CHARGES VOLUME DISCOUNT mine we ma $010.001 o mil. U.S.A.. 3.112161 :7.4~o, mar ma Me.o rho Mo. eueer 02. o.n.o....row D1., 0041421,. arcrep entire 162 *411.00010490 Aye. co- U.N Add 12.00 D.00-4 1161 NET 11444.. C0.11011 and Memo 10.00425.00 Add 00.75 11 100.004249.11 Lees 105. V/KE0 OROIRIIIG BY PM0116 CALL I 100 344 4531 MK. call 311 611 51741. 111 NAIL SDID YOUR ORDER TO, DIGI KEY. P.O. Bo 177, 11770 Lot 74114. MO 54701. 25.00-4111.1111 A0010.54 K 250 00-441111.111, Lees 15% 50.01655.1111 You mm oar to circk marry ark, Maur Chao', VISA pCOD 040,1. f GOARANTUs Any pens ...... 4,94.041 burn 0.9 15. 1.41 D.. to rep1000 or refund Add $0.25 500.00411111.1111 Loo. 20% ad " ...honed 10 der loacro roam,. min coo, o¿yourmoce TIICF,LIMIIJECTTOCIIeNtm 11,111001.0 00071001 $1110& Up No Choi. $10D0 & Up Less 25% CIRCLE 82 ON FREE INFORMATION CARD 87 Mad Grdar Electronies WPrldwide ameco ® Mail -Order E ELECTRONICS 415-592-8097 NEC V20 & V30 CHIPS COMMODORE CHIPS SATELLITE TV Replace the 8086 or 8088 in Your IBM-PC and Part No. Poco Part No. Arce Part No. Arce DESCRAMBLER CHIP Increase Its Speed by up to 40%! The MM5321 is a TV camera sync generator designed to WC/17700,h Cuol 4995 14.95 6551 ACTA 329 8722 MWAU 9.95 Part No. Price supply the basic sync lunction5 for either color or mono- Pos0ew 6560 VIC I 10.95 '251104.04 Kemal ROM 10.95 SI -3052P 50 chrome 525 lene 60Hz mlerlaced and camera video recorder (5MHz) V20 Chip 5 9.95 318018-03 Rasen RUM C128... 15.95 UPD70108-5 Vdlder Rep 2A 5.95 6567 V,.11 14.95 applications COLOR BURST GATE & SYNC 318019-03 Basic ROM C128...15.95 UPD70108-8 (8MHz) V20 Chip 511.95 6502 MPU wnnl Clock 2.25 6569 II, PAL 44-9510.95 ALLOW STABLE COLOR OPERATION ... Kemal ROM -0128... 15.95 6572 r C PAL N. ".10.95 3181)20-04 UPD70116-8 (8MHz) V30 Chip 514.95 6504A CPU 1.95 3253 611 RAM for1541 MM5321N $11.95 6581 U 11751. . 14.95 UPD70116-10 (10MHz) V30 Chip.... 534.95 6507 CPU 495 3.49 154°1 Cure 15.95 6582 D19á).... 14.95 6510 CPU 9.95 '325572-01 Loprc Array 24.95 8360 L ° Edmnp..10.95 INTERSIL Also Available! 7400 6520 RA 1.75 825100PLA IR06114 011" 13.95 8501 MPU 10.95 901225-01 Cter R09 11.95 Part No. 1.9 101 Pan No. 1-9 104 6522 VIA 2-95 8502 MRl ...795 5.95 901226-01 BASIC ROM 11.95 74HC HI -SPEED CMOS 6525 MI 7-95 4.95 7400 .. 29 19 7485 . 65 55 8563 CR1 Cono .. 15.95 901227-03 Kenny ROM 11.95 Part No. Price Part No. Price 7402 29 .19 7486 . 45 35 6526 CIA 14.95 8564 V11 ..159512.95 901229405 Uollade ROM 748000 .25 7480175 69 7404 .. 35 25 7489 .. 2 05 195 6529 áP1 495 2.95 8566VICPAL 499515.95 (For 1541 Usk Dnwl 15.95 49 748002 ...... 25 7480221 . 99 7405 ... 39 29 7490 39 653212868AM.00 IrmA1 8701 6.49 Dock Clip ... 9.95 No specs available 7411004 .. 29 7480240 . 79 7406 . 39 29 7493 .. .45 .35 6545-1 CRIC 2.49 '8721 PLA 14.95 "Note: 82S100PLA . U17 (C-641 748008 ...... 29 7480244 79 7407 39 29 74121. . . 45 35 7411010 .. . 29 7480245 ... 89 7408 . 35 25 74123 . 59 49 .. 49 74110253... .59 7410 35 25 74125 .55 .45 MICROPROCESSOR COMPONENTS 748014 ...... 748030 .. .. . 29 7480259...... 65 7414 .49 39 74126 75 65 MISCELLANEOUS CHIPS 6500/6800/68000 Cont. 8000 SERIES Cont. 748032 . 29 7480273. . 79 7416 .45 35 74143 4.05 395 Part No. Price Part No. Part No. Price Rice 748074 .. . .. 39 74110373 ...... 79 7417 .. .. 45 .35 74150 . 135 125 7411075...... 39 7480374...... 79 1 6840. 3 95 8228. 7420. . 35 25 74154 1.35 25 D765AC. 4.49 2.49 14 95 6843 ...... 2.95 4.95 74HC76 .. .. . 45 7480393...... 75 7430 . . 35 25 74158 .. 159 149 WD1770. 1995 ...... 2.95 74HC85 .. .. 79 74HC595 . .. 1 19 7432 39 29 74173 85 75 2661-3. . 5 95 6845 8243. 225 ... t 6850 49 7411086 39 7480688...... 79 7438 . .39 .29 74174 65 55 WD9216. 99' 695 8250A 549 8852.. .' 9952'49 8250B IBM) ....6.95 7480 123 ... .. 89 74HC4040 .. 89 7442 . 55 45 74175. . 65 55 280, 2804. 2808 SERIES "" )For 6875 895 8251A 175 74110125. . 49 741104049 59 7445 . 79 69 74176 .99 89 7v1C.G8000L8 11 95 8253-5 .. 195 74HC 132 ...... 49 74804050 . .59 7446 .89 .79 74181 195 185 Z80-CTC...... 1 79 MC680001_10/995 1495 8254...... 495 7480138 . . . .. 49 741104060 ...... 109 7447 . .. 89 79 74189 .2.05 195 Z80 -DART...... 495 8000 SERIES 7480139...... 49 74804511 . 129 . 8255A-5 ... 169 7448 2 05 1.95 74193 .79 .69 Z80-PIO...... 1.79 8031 2 95 1.19 741104514 8257-5 ...... 7480 154 ...... 1.19 . . 1.85 1.75 149510.95 249 7472. ... .75 65 74198 280A. . .. 1.35 80C31BH. . 8259-5. . . . . 1.95 741104538 . 89 7473 ... .45 .35 74221 . . .99 .89 280A-CTC...... 1.49 8035 .. .149 ... 74HC 174. . .69 . 1.19 . . . 74(104543 7474 45 1.95 8073 ...... 29.95 ... 35 74273 205 Z8OA-DART. . . . 4.95 8080A . 2.49 8279-5 . . . . . 2 95 7475 .49 74365 .69 59 1 49 39 280A-P10 8741 7476 .45 35 74367 69 .59 4.95 8085A ...... 29 74HCT CMOS TTL Z80A-510/0. .. .. 695 8748D 25V1 .. 9.95 - 2808 87481-1016(5112101.. 10.95 7411C700 29 74H01139 59 74L S Z806-CTC . .. 349 808715MHz) 12500 8749. ....9.95 748CT02 29 74HC1157 69 280B -P10 .. 429 .. .. 74)10104 .29 741500 29 19 7415165 75 65 . 8751 39.95 74801174 69 6500/6800/68000 SER. 8755 1495 74110108 29 7461C7175 69 741502. . 29 19 7415166 99 .89 88&2BMliZ) 156á9

6502 . DATA ACQUISITION 74HCT10 29 7414C7240 99 741504. .. 35 25 7415173. .. 59 49 225 8088-2 . 895 65002 (CMOS) 8.95 .. 495 ADCO804LCN 3.19 74110132 29 741-10244 99 741505.. . 35 25 7415174 . 49 39 8116 ...... 1.75 7411C1245 6520 8155 ...... 195 ADC0808CCN .5.95 748C774 49 119 741506 . .109 99 74LS175 . 49 39 . . . . 2 6522...... 741_507. 109 99 7415189 ..4.59 4.49 95 8155-2 . . 2.49 ADC0809CCN 395 74HCT86 49 74HCT373 119 6532. . . . . 6.49 ADC0816CCN ...1495 741508 29 19 741_5191 59 49 8156 3 95 741-1C7138 59 746101374 119 6551 ...... 3 29 8202 9 95 ADC0817CCN....8.95 741510 . . 29 19 741_5193 . . 79 69 6800 . . . . 1.75 8203 14.95 DAC0808LCN .. . 1.95 741_514.. .49 .39 741_5221 .69 .59 CMOS . 74C 6802 . 3 49 8212...... 1.49 DAC1008LCN 649 - .35 74(.5240 79 741527, 25 ... 69 . 6810 . .. 125 8224 . 225 AY -3-1015D 4.95 74000 .. 29 74C174 ...... 79 741530 29 19 7415243 . 79 69 6821 .. . 129 8228. 2.49 AY -5-1013A 995295 74002 . . 29 74C175 . . . .. 79 741532 .35 741_5244 .. .79 69 25 ...... 1 74C04. . . . . 29 74C221. . 49 74LS42. .. 49 .39 7415245 . .89 79 DYNAMIC RAMS 74008 . . . . .35 740240 . . . . 1.29 741_547 .99 89 7415259 . .99 89 Part No. Function Price . . . . . 1 74010. . . . .35 74C244...... 29 29 741_5273 79 74LS73 .39 89 . 74014. 49 740373...... 1.49 4116-15 16.384 x 1 (150ns) . .. 89 741574 .35 25 7415279.. 49 39 74C32...... 35 74C374...... 149 39 29 74LS322 4128 20 )Piggyback) 131,072 x 1 2000s). . ... 4491 325 741575 ...4.05 395 . . 74C74...... 59 740912 . . . . 7.95 741_576 45 7415365 49 4164-120 65,536x 1 (120n5)...... 1.75 55 .. .39 1 74085...... 139 740915 .. . . 39 741585. .. 59 .49 7415366 .49 .39 4164-150 65.536x 1 (150ns) ...... 1.15 74086...... 35 74C920 ...... 9.95

1 . . . 741 SAE 35 25 7415367 . .49 39 4164 200 65.536 x (200ns) . . . .. 74C89 . . 5.19 74C921 . . . . . 9.95 74LS90 .49 39 7415368 . 49 .39 TMS4416-12 16.384 x 4 (120ns) . . .. . 495 375 . 99 74C922 ...... 3 95 741593. .. 49 39 7415373 .. 79 69 8118 16.384 x 1 )120ns) .69 74C 154...... 2 95 740923 .. 3.95

. 1 . . . . 7415123 .59 49 7415374.. .79 69 41256-120 262.144 x )1200s). . 3.95 740173 . . 1 05 74C925 5 95 7415125. 49 39 7415393 89 79 41256 150 262.144 x 1 (1500s). . . 995 2.75 741_5138. .49 . 5.95 39 7415590 6.05 50464-15 65.536 x 4 (150ns) (4464) (41464). . . 4.95 LINEAR 139 1 7415 ... .49 .39 7415624 .. 2.05 95 511000P-10 1,048.576 x 1 (100015) 1 Meg . . 9995 27.95 D50026CN .. 1.95 LM1458N . .. 39 741_5154 .109 99 7415629. .2.29 219 514256P-10 262,144 x 4 (100r15) 1 Meg 4495 29.95 ..... 741_5157 45 35 741_5640 .. 1.09 .99 TL074CN .. .. . 89 LM1488N 49 7415158 45 35 7415645 ..109 99 STATIC RAMS 7L084CN ...... 99 DS14C88N(CMOS) 1.19

. . . . AF 100-ICN 895 LM1489N. . . 49 7415163 59 49 7415670 109 99 2016-12 2048 x 8 i 120r1s)...... 1.69 1 LM307N...... 45 DS 14C89N 1CMO51 19 7415164 59 49 7415688 205 195 2102-21. 1024 x 1 12500s) Low Power (91 L132) 1 95 . . . . . 1 1496N . . . x 4 LM309K 25 LM .85 2114N 1024 145Ons)...... 99 .. 1 LM31 N...... 45 MC 1648P . . . . 4.95 21 14N-2 1024 x 4 (2000s) ...... 1.05 74S/PROMS 1M3177 . . . . . 79 LM 1871 N . . 295 2114N -2L 1024 x 4 1200ns) Low Power. 1.49 74S00 29 745188' 129 LM318N ...... 99 LM1872N . ... 295

1024 11 . . . 4 . 21C14 (CMOS). .. 49 . . 74504 .. 35 745189 1 69 (2000s) LM319N .99 LM 1896N-1. 1.59 74508 ... 35 745196 2 49 2149 1024 x 4 (45ns). LM323K .. . .. 3.95 ULN2003A .. 99 5101 256 4 (450ns) CMOS. LM324N . . 39 X82206 . .. .. 3.95 74S10 . 29 745240 1.49 74532 35 745244 1.49 61 16LP-2 2048 x 8 (12085) Low Power CMOS...... 295 LM338K . 495 XR2211 LM339N.. . 082243 . . . 39 ..195 74S74. 45 745253 79 6116P-3 2048 x 8 (150n5) CMOS . . . . 189 LF347N . 179 1)52615290N .. 4.49 74585 . .. 1 79 745287' 149 61161P-3 2048 x 8 (150ns) Low Power ...... 1.95 LM348N ...... 69 D526L531CN .. 1.19 74586...... 35 745288'. .. 1 49 6264LP-12 8192 x 8 )12Ons) Low Power CMOS...... 4.25 LM3507 . . 2 95 DS26LS32CN .. 1 19 74S 124 . 2 95 745373 149 6264P-15 8192 x 8 11500s) CMOS. .. . 3.59 LF351N .. . .. 39 D526L533CN .. 195 745174 ...... 79 745374. 149 6264LP-15 8192 x 8 (I 50ns) Low Power CMOS .. 3.75 LF353N .. . . 49 LM2901N .. . 49

. 745175, .. .79 745472'.. 2 95 6514 1024 x 4 , . 449 ..... )350ns) CMOS (UPD444C). 3.95 LF355N . ... .79 LM2907N 249

. . 1 43256-151 32.768 x 8 1150ns) Low Power .. £495 17.95 LF3` v .. .. .79 LM2917N 18 pin). . 55

LF357N . . 1.09 MC3419CL .. .. 9.95 74F PROMS/EPROMS LM358N .. 49 MC3446N ..2.95 74F00 .. .. 39 74E139 .. 89 1702A yis) 256 x 8 11 . . . . . LM360N . .. .. 2.19 MC3450P .. .. . 2.95 . . .95 74E04. ... 39 74E157 ...... 4.95 . TA452516 2048 x 8 (450ns) 25V LM361N . . 179 MC3470P .. ... 1.95 74F08 . .. . . 39 74F193 .. 3.95 7M52532 4096 x 8 (450ns) 25V 595 695 LM380N-8 . 99 MC3471P . .. 4.95 74E10 .39 74E240 .... 1 39 112.152564 8192 x 8 1450ns) 25V 8.95 .99 MC3479P . . . . . 4.79 1 74F32 ...... 39 74F244. . 39 . 2708 1024 x 8 145 5) 495 LM387N . 99 MC3486P. 1.69 49 74F253 . . 74F74 .. 99 . 78452716 2048 x 8 1450ns) 3 voltage 995 LM393N ...... 39 MC3487P .. 1.69 74E86 .59 74F373 1 39 LM3900N . . 49 ...... LM399H .. 2716 2048 . 8 1450ns) . . . . 3.75 ..2.95 74E138 .. . . 89 74F374 .. 1 39 . . 1.19 2716-I 2048 x 8 (35Ons) 25V. 495 LF411CN .79 LM3905N LM3909N. . . . 99 TL497ACN . . 2.69 27C16 2048 x 8 (45Ons) 25V (CMOS)...... 649 LM3914N . . . . 1.95 CD-CMOS 2732 4096 x 8 )450ns) 3.95 NE540H (C540H) . . 2 95 . 1 95 NE555V...... 2g LM3916N CD4001...... 19 CD4076 . . . . . 65 4096 x 8 (200ns) 21V ...... 4 25 2732A-20 75 NE5532 . .. 89 X/T-L555. .. . . CD4008 .. .. . 89 CD4081 . ... . 25 2732A 25 4096 x 8 (250115)21V...... 3.95 NE5534. LM556N ... . 49 . . . 19 . . . CD4011 CD4082 25 ...... 2732A 45 4096 x 8 (450ns) 21 V. 3.75 NE558N.. .. 89 7805KILM340K-51..129 ...... 29 CD4093 . . . . 35 CD4013 27032 4096 x 8 )450ns) 25V (CMOS)...... 649 7812KILM340K-121.129 LM565N...... C04016 . . 29 CD4094 .. 89 7815KILM340K-151 129 x . . . 4 25 , 2764-20 8192 8 (20005) 21V LM567V . . ... 69 CD4017...... 55 CD40103 . . . . . 2 49 7805T)LM3407-51. .49 . . . 2764-25 8192 x 8 (250115) 21V 3.75 NE592N , 89 C04018 ...... 59 CD40107 . . . . 69 78121 ILM340T-121. .49 2764A 8192 x 8 12.5V.. . . 4 25 29 25 (250ns) LM741CN . .. 004020 59 CD40109 . 149 78157 11..M3407-15)49 . 2764-45 8192 x 8 (450ns) 21 V ...... 3 49 LM747CN 59 7905K ILM320K-5) 135 . . . . 49 . . . CD4024. CD4510 69 27C64 x 8 1450ns1 21V (CMOS 8192 I 549 MC 1350 ...... 1.49 79057 . . .59 CD4027 .. . 35 CD4511 69 ILM3207-51 27C64-15 8192 x 8 )15Ons) 21V (CMOS) 6.49 MC1372P .2.49 75472 . . CD4030 . .. 29 CD4520 .. 75 128K . . . 27128-20 16 384 08 (2000s) 21V 595 MC1377P...... 319 75477 . . 129 C04040 .. . 65 CD4522 .. . .79 27128-25 16.384 x 8 (2501s) 128K 21V 525 MC1398P ...... 895 'b477 595 CD4049 . .. 29 CD4538 . 79 27128A-25 16.384 x 8 (25Ons) 12.5V. 495 LM1414N...... 129 MC145406P .. 295 CD4050 . . .. 29 CD4541 . . . 69 21V 27C128-25 16,384 x 8 (250ns) (CMOS)...... 595 CD4051. . . . . 59 CD4543. . . 79 27256-20 32.768 x 8 256K (12.5V)...... 695 C04052.....59 CD4553 . . . 4.95 (200ns) IC SOCKETS

27256-25 . 8 256K . . . 595 ...... 32,768 1250r1s) 112.5V). CD4053 . .. 59 CD4555. 79 Low ProfIle Wee Wrap (Gold) Level 03 x 256K (CMOS) . . . . 895 CD4059 . . . 3 95 CD4566 2.49 27C256-25 32.768 8 (250ns) (125V). 8 pin LP ... 11 Hpin WW .... 59 x 8 ...... 1995 . 1.95 27512-25 65.536 (250ns) 512K 112.5V1.. CD4063 .. CD4572(MC14572) .39 14 pen LP...... 12 14 pen WW . 65

. 1595 . . x CD4066 . 29 CD4583 .. 89 68764 8192 8 145055) 25V 16 pin LP...... 13 16 pin WW 69

...... 1695 CD4069 .. ... 25 CD4584 39 68766 8192 x 8 (35Ons) 25V ...... 24 pin LP...... 25 24 pal WW .... 1 19 1 ...... 89 x 4 PROM 29 CD4070 .. 25 CD4585 745387 256 0 28 pen LP 27 28 pin WW , 139 1 . . . . . MC 1441 P . . 895 4.95 CD4071. 25 745471 256 x 8 PROM TS. 40 per LP 29 140 pin WW 1 89 ...... 25 . . . . 4 49 CD4072 MC14490P N825123 32 x 8 PROM TS 2 49 Soldered Standard )Gold 811010 Header Plug Sockets Also Available PARTIAL LISTING OVER 4000 COMPONENTS AND ACCESSORIES IN STOCK! CALL FOR QUANTITY DISCOUNTS

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COMMODORE! COMPATIBLE NOW YOU CAN BUILD AN IBM PC/XT COMPATIBLE! APPLE COMPATIBLE ACCESSORIES Jameco's IBM PC/XT Compatible Kit ACCESSORIES 4164-150 128K RAM (it :;hips).... 520.70 Ja® Parallel Printer Card IBM -FCC Floppy Control er Card .. VI:/ 534.95 for Apple 1I, II+ and Ile IBM -Case Flip -Top Case 534.95 JE1015 XT/AT Style Keyboard - $59.95 Intelligent interface lo JE1030 ISO wan Power Supply 569.95 most dot matrix graphics JE1050 Mono/Graph. crd w/PPod 569.95 printers VE JE1020 5t.. DSDD DrsL Drive 599.95 HESWARE 300 Baud Modem IBM-MON 12 Mono. Green Monitor 599.95 Centronics standard FOR VIC-20 AND C-64 5p 36 IBM -MB KT Motherboard IZero-K RAM-incl. Advanced text printing Connects directly to User Port Manual Answer/ 5g0 DTX/ERSO BIOS ROM) 599.95 Dial Function keys defined for convenience a PC JE880 Parallel Printer Card S49.95 Includes Midwest Micro Associates communi- %ewe FREE! QUICKSOFT cation software. WRITE WORD PROCESSING JE383 64KBuner for JE880 $69.95 $49.95 CM -1 (ForVIC-2o and C-641 $24.95 $19.95 s;lt,t,t1". SOFTWARE INCLUDED! JE8803 JE880andJE883 $99.95 S89.95 External Power Supplies /L_= ' Weight: 48 lbs. Regular List S590.30 Extended 80 -Column for Apple Ile CPS -10 (For C-64) $39.95 JE1004 (Includes 9 items above) $499.95 JámécóCard CPS -128 (For c-128) $59.95 80 Col 1646 RAM . Doubles ADDITIONAL ADD-ONS AVAILABLE! amount of data your Apple ,le can display as well as its mom RS232 Interface for RS232HC RS232 serial Half Card $ 29.95 ory capacity ' Ideal word Allows connection of standard serial devices. processing Complete with EM -100 Expansion Memory Half Card (without RAM) $ 59.95 instructions JE232CM (For viC-2o.0-6480-128) $39.95 JE1052 Integrated Color Graphics Board $ 59.95 -Open aion with the C 128 in 64 mode only JE1078 Multifunction 0-384K RAM (without RAM) $ 89.95 JE864 $59.95

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CIRCLE 114 ON FREE INFORMATION CARD Computer Power Command Center for only $39.95! !Ci. II: At this price theywon't last ¡1' long, so order yours today!

This superb monitor stand puts control TILT & SWIVEL POWER COMMAND of your entire system at your fingertips! $3995 Our special purchase of these units X-1128 can put one in your hands at an unbeatable price!

(ret rid of that confusing maze of wires and ease operator fatigue with this one fantastic product! 711e monitor stand swivels 360° and tilts I 2.5° to improve line of sight and minimize glare. The electronics built into the base provide EMI filtering and surge & spike protection for five component inputs. You can plug your computer, monitor, printer, and two other devices into the 3 -pin sockets in the hack of the stand and control them individually with the lighted rocker switches on the front Or turn the entire system on and off with the master control switch! Built-inspike ¿Surge SIZE: 11"W x 10'/.'0 x 31,4"H Protection! WEIGHT: gibs. Compare z POWER CORD: 54" 14 AWG x 3C CIRCUIT BREAKER: 15 Amp Our Price! Dealer Inquiries welcome! Just circle reader service number 189 20MHz Dual Trace Scope Price Breakthrough!

was 5399 - SAVE $80 now $310V Includes quality probes (x1,x10,gnd) 0-1240 Built-in component tester IN TV -video sync filter X - Y operation CRT Probe wiar Z-axis (intensity modulation)

1 year warranty

( - 2 95 15 MHz i PORTABLE 20 MHz 35 MHz 50 MHz I© f 0-1245 SPECIFICATIONS DUAL TRACE DUAL TRACE DUAL TRACE DUAL TRACE Versatile probe suits virtually any scope. It features built in x1/x10 switch. 4' of SHIELDED cable with BNC connector, and wandering Rise time (use) 24 <17.5 <10 <7.7 earth lead with alligator Clip, insulating shroud. Max input 600V p -p or 300V ± peak AC) (DC Spectflcohort Working voltage - 600V' PI, (or 600V DO Band mdth - Input impedance 1M ohms shunted by 20pF ± 3pF for all models x1 DC-10MHz/z10: DC-100MHz input revstance-x1:1 M ohnx10 Chop frequency 200 KHz (approx) for all models 10M ohm Input capacitance -x1 40pF 8CRO input c./.10. 10- Channel separation 60dB @ 1KHz 60dB @ 1 KHz 60dB @ 1 KHz 70d8 @ 1KHz 60pF REF position -probe grounded via 9M resistor. Time base .5 usec .5sec .2 usec to .5 sec .1 usec -.5 sec 2 usec-.5 sec CRT 95mm Cat No 0-1244 0-1240 0-1241 0-1243 Pleeee Mote: Sale paces are evarlaNle by MAIL ORDER ONLY. You NOW $349 $319 $449 $649 must mention this ad and quote the prices on the items you wise. offer valid through July 31. 1987 or whole 'supplies last - quantities ere limited, so SAVINGS $150 880 $150 $250 hurry, All 'scopes are supplied with schematics 14 -Day Satisfaction Guarantee Order by Phone MAIL ORDERS 415-368-1066 Mon - Fri 7am - 6pm DSE, P.O. BOX 8021, Redwood City, CA 94063 Pacific Time EL±z We ship UPS Ground unless otherwise requested Add 5% of order total ICS (mm Si 501 for shipping Outside USA add 20% (min 54) There is an additional Stores m 81 RKEL EY Ca i4 150 486-0 755 REOWCOOCITY C41475(368-8844 SAN JOSE CA14081241 2266 51 50 handling fee California residents please add sales ra. VISA and MASTERCARD welcome Minimum order value 520 00 To receive your copy of our colorful 148 page catalog, circle Reader Service 190 90 Tenma Soldering Station Adjustable temperature range of 150* -420°C (300°- 790°F) Grounded tip for soldering static sensitive devices Overheat protection with closed loop Here is just a temperature control Replaceable iron clad tip Improved circuit design for greater temperature stability

sample of what Deluxe Anti -Static Desoldering Tool -.: . 7Y Rugged metal construction Anti- . static tip Nozzle cleaner .,WI 3,-. Lightweight and compact y Disassembles easily for cleaning you'll find at 734" long x 34" diameter

MCM Electronics Additional Soldering Equipment can be found on pages 137 and 138 of Catalog #15

Tenma 15MHz Dual Trace Portable 0 Super Wash Oscilloscope Powerful spray intricate Dual trace model capable of cleans electronic assembly without j harming plastics Dries instantly a Spray literally blasts dirt displaying signals up to 15MHz, and grease away 24 oz. for up to two hours on a single charge of its internal battery Power can be supplied from either a 12VDC or 120/240V 50/60Hz AC source Tuner Cleaner e Cleans, lubricates, protects a Cleans and restores dirty and Tenma 10 Amp Regulated Power Supply corroded contacts Doesn't harm plastics 16 oz. Output: Regulated 13.8VDC Input: 120VAC Fuse protected u With easily accessible fuse holder Neon light indicator Heavy duty binding posts Effective heal sinks for more power dissipation a Output current: 10 amp one Wire Stripper and Cutter minute on, three minutes oft 7 amp continuous Made of tempered steel Adjustment can be set for wire sizes 10-24 gauge a Return spring Tenma LCR Meter Cushion grip u 5'!" long LCR Meter provides a convenient way to accurately measure inductance, capacitance and resistance (.01ohm resolution) on its 31/2 digit LCD display. For more Chemicals and Tools see pages 128-136 of For more specs and Test Equipment see pages Catalog #15 146-154 of Catalog #15

Anti -Static Work Mat Diskette File Box e A must for the modern service shop. up to 70 a made Use in conjunction with our Stores - 5W' diskettes Case #21-660 wrist strap to help of anti -static ABS plastic with smoked acrylic eliminate static related problems cover Six adjustable index dividers 18" x26" Deluxe Joystick for Atari and Commodore Anti -Static Wrist Strap ra For use with Atari, Commodore and other This wrist strap when used with our VCS compatible systems Two firing buttons anti -static work mat, will effectively 5.5' cord with 9 pin plug dissipate static charges u The five foot

coiled, cord with 1 Mohm resistor, snaps to wrist strap to give user added mobility Cord is terminated with a banana plug and alligator clip For complete information see page 136 of Catalog #15 \imminur.

Catalog #15 has other Computer Equipment and Accessories Be To Call For on pages 119-127 Sure © 1987, MCM Electronics Your FREE Catalog! w MCM ELECTRONICS Over 7,000 Items! 858 E. CONGRESS PARK DR. CENTERVILLE, OH 45459 Call Toll Free 1-800-543-4330 A PREMIER Company

In Ohio 1-800-762-4315 CIRCLE 87 ON FREE INFORMATION CARD In Alaska and Hawaii 1-800-858-1849 SOURCE CODE: RE -35

91 1200e MODEM $9995 FSOF WA E/ 2400e MODEM $19995 STATIC RAMS * * * * HIGH-TECH * * * * EPROMS 2101 256.4 (450na1 1.95 2708 1024.8 (450ns) 4.95 5101 256.4 (450ns)1CMOS) 3.95 2716 2048.8 (450ns115V) 3.49 21021-4 1024.1 1450ns1(LP) .99 NEC V20 UPD70108 $1195 2716-1 2048.8 1350ns115V1 3.95 2112 256.4 1450ns) 2.99 TM52532 4096.8 (450ns)15V) 5.95 2114 1024.4 (450ns) .99 REPLACES 8088 TO SPEED UP IBM PC 11-40% 2732 4096.8 (a50ns115VI 3.95 21141.4 1024.4 (450ns1(LP) 1.09 2732A 4096.8 (250ns)(5V)121V PGM) 3.95 21141-2 1024.4 (200ns)(1P) 1.49 ° * HIGH-SPEED ADDRESS CALCULATION 2732A-2 4096.8 (200nq(5V)(21V PGM) 4.25 21141-15 1024.4 (150ns)(11,) 1.95 27C64 8192.8 (250ns))5VI(CMOS) 5.95 TM54044.4 4096.1 (450n.) 1.95 IN HARDWARE 2764 8192.8 (450ns)(5V) 3.49 TMM2016.150 2048.8 (150ns) 1.49 * PIN COMPATIBLE WITH 8088 2764-250 8192.8 (250ns(15V) 3.95 TMM2016.100 2048.8 (10Ons) 1.95 2764-200 8192.8 (200ns)(5V) 4.25 HM6116 4 2048.8 (200ns)(CMOS) 1.89 * SUPERSET OF 8088 INSTRUCTION SET MCM68766 8192.8 1350ns1(5V)(24 PIN) 17.95

HM6116-3 2048.8 (150nsI(CMO5) 1.95 27128 16384.8 (250ns)15 V 1 4.25 HM6116LP-4 2048.8 (200ns)(CMOSIILP) 1.95 * LOW POWER CMOS 27C256 32768.8 (250ns115V1(CMOS) 10.95 HM6116LP-3 2048.8 (150na)(CM05)(LP) 2.05 27256 32768.8 1250ns115V1 7.49 HM6116LP-2 2048.8 (120n.)(CMOSI(LP) 2.95 8MHz V20 UPD70108-8 $13.95 5V Single 5 Volt Supply 21V PGM- Program at 21 Volt. HM6264P-15 8192.8 (150na)(CMOSI 3.89 HM6264LP-15 8192.8 (150ns)1CM051(LP) 3.95 8MHz V30 UPD70116-8 $19.95 HM6264LP-12 8192.8 (120ns)(CMOS)(LP) 4.49 LP=Low power SPOTLIGHT FSPECTRONICS * * * * * * * * CORPORATION EPROM ERASERS DYNAMIC RAMS 4116-250 16384.1 (250n0 .49 4116-200 16384.1 (200ns) .89 PE -14T 4116-150 16384.1 (150ns) .99 4116-120 16384.1 (120ns) 1.49 MK4332 32768.1 (200ns) 6.95 ORDER TOLL FREE /0 4164.200 655360 (200ns)(5v1 1.19 4' 4164.150 65536.1 (150ns)(5v) 1.29 allYO, 4164-120 65536.1 (120ns)(5v) 1.95 MCM6665 65536.1 (200n.)(5v) 1.95 TMS4164 65536.1 (150ns)(5v) 1.95 2.95 800-538-5000 4164 -REFRESH 65536.1 (150ns)(5V)(REFRESH) Capacity Intensity Unit TM54416 16384.4 (150ns)(5v) 4.95 Model Timer 41128-150 131072.1 (150ns)15v) 5.95 Chip (uW Cn,) Price TMS4464.15 65536.4 (150nsK5v) 6.95 PE -14 NO 9 8.000 $83.00 2.95 41256.200 262144.1 (200ns)(5v) MastetCord PE -141 YES 9 8.000 8119.00 41256150 262144.1 (150n.)(5v) 2.95 PE -241 VES 12 9.600 3175.00 5v=5ingle 5 Volt Supply REFRESH -Pin 1 Refresh SnIS

8000 CRT 6500 CRYSTALS 741.500 HIGH SPEED CMOS 8035 1.49 CONTROLLERS 1.0 MHz 32.768 KH, .95 741500 .16 7415165 .65 A new family of high speed CMOS logic featuring 8039 1.95 1.0 MHs 2.95 741.501 .18 7415166 .95 the speed of low power Schottky 18ns typical gate 8080 2.95 6845 4.95 6502 2.69 1.8432 2.95 741.502 .17 7415169 .95 propagation delay). combined with the advantages of 8085 2.49 68845 8.95 65CO2ICMOSI 12.95 2.0 1.95 741.503 .18 CMOS: very low power consumption. superior noise 9.95 741_5173 .49 8087-2 169.95 6847 11.95 6507 2.097152 1.95 741504 .16 7415174 .39 immunity. and improved output drive. 1.95 8087 129.00 HD465055P 6.95 6520 2.4576 1.95 741505 .18 7415175 .39 4.95 8088 6.95 MC1372 2.95 6522 3.2768 1.95 741508 .18 7415191 .49 74HCOO 6526 26.95 8088-2 9.95 8275 26.95 3.579545 1.95 741.509 .18 7415192 .69 74HC: Operate at CMOS logic levels and are deal 6532 6.95 8155 2.49 7220 19.95 4.0 1.95 741510 .16 7415193 .69 for new. all-CMOS designs 8155-2 3.95 CRT5027 12.95 6545 6.95 4.032 1.95 741511 .22 7415194 .69 5.95 74HC00 .59 74HC148 1.19 8748 7.95 CRT5037 9.95 6551 5.0 1.95 741.512 .22 7415195 .69 6561 19.95 74HCO2 .59 74HC151 .89 8755 14.95 TM59918A 19.95 5.0688 1.95 741.513 .26 741S196 .59 6581 34.95 74HC04 .59 74HC154 2.49 80286 129.95 6.0 1.95 741514 .39 741S197 .59 74HC08 .59 74HC157 .89 80287 199.95 2.0 MHz 6.144 1.95 741515 .26 7415221 .59 74HC10 .59 74HC158 .95 6.5536 1.95 741520 .17 741.5240 .69 74HC14 .79 74HC163 1.15 DISK 6502A 2.95 8.0 1.95 741521 .22 7415241 .69 74HC20 .59 74HC175 .99 6520A 2.95 10.0 1.95 741522 .22 7415242 .69 74HC27 .59 74HC240 1.89 CONTROLLERS 6522A 5.95 10.738635 1.95 741527 .23 7415243 69 1.89 8200 11.95 74HC30 .59 74HC244 1771 4.95 6532A 12.0 1.95 741528 .26 7415244 .69 .69 1.89 7.95 1.95 74HC32 74HC245 8203 24.95 1791 9.95 6545A 14.31818 741530 .17 7415245 .79 74HC51 .59 74HC257 .85 8205 3.29 1793 9.95 6551A 6.95 15.0 1.95 741.532 .18 7415251 49 74HC74 .75 74HC259 1.39 8212 1.49 16.0 1.95 741.533 .28 7415253 .49 1.35 74HC273 1.89 1795 12.95 3.0 MHZ 17.430 74HC85 8216 1.49 1797 12.95 1.95 741537 .26 7415256 1.79 74HC86 .69 74HC299 4.99 8224 2.25 65028 6.95 18.0 1.95 741.538 .26 7415257 .39 1.19 74HC368 4.95 2791 19.95 74HC93 .99 8237 18.432 1.95 741542 .39 7415258 .49 .79 2.29 2793 19.95 1.95 74HC107 74HC373 8237-5 5.49 2797 29.95 20.0 741547 .75 7415259 1.29 74HC109 .79 74HC374 2.29 8250 6.95 6843 19.95 22.1184 1.95 741.548 .85 7415260 .49 74HC112 .79 74HC390 1.39 8251 1.69 8272 4.95 6800 24.0 1.95 741551 .17 7415266 .39 74HC125 1.19 74HC393 1.39 8251A 1.89 UPD765 4.95 32.0 1.95 741.573 .29 7415273 .79 7414C132 1.19 74HC4017 1.99 8253 1.89 12.95 1.0 MHZ 741574 .24 7415279 .39 74HC4020 1.39 1.95 M68876 CRYSTAL 74HC133 .69 8253-5 MB8877 12.95 6800 1.95 741575 .29 7415280 1.98 74HC138 .99 74HC4049 .89 8255 1.69 1691 6.95 6802 4.95 OSCILLATORS 741576 .29 7415283 .59 74HC139 .99 74HC4050 .89 8255-5 1.89 2143 6.95 6803 9.95 741583 .49 7415290 .89 8259 1.95 6809 5.95 1.0MHa 5.95 741585 .49 7415293 .89 8259-5 2.29 1.8432 5.95 74LS86 .22 7415299 1.49 74HCTOO 4.95 6809E 5.95 8272 6810 1.95 2.0 5.95 741.590 .39 7415322 3.95 744ICT: Direct. drop in replacements for LS TTl 8279 2.49 2.4576 5.95 741592 .49 7415323 2.49 and can he intermixed with 7415 in the same circuit. BIT RATE 6820 2.95 4.95 8279-5 2.95 1.95 2.5 741593 .39 7415364 1.95 74HCTOO .69 74HCT166 3.05 3.95 6821 4.0 4.95 8282 GENERATORS 6840 6.95 741.595 .49 7415365 .39 74HCT02 .69 74HCT174 1.09 8284 2.95 19.95 5.0688 4.95 7415107 .34 7415367 .39 74HCTO4 .69 74HCT193 1.39 MC14411 9.95 6843 4.95 8286 3.95 12.95 6.0 741.5109 .36 7415368 .39 74HCT08 .69 74HCT194 1.19 4.95 BR1941 4.95 6844 8288 6845 4.95 6.144 4.95 7415112 .29 7415373 .79 74HCT10 .69 74HCT240 2.19 4702 9.95 8.0 4.95 7415122 .45 7415374 .79 .69 74HCT241 8.95 6847 11.95 74HCT11 2.19 COM8116 10.0 4.95 7415123 .49 7415375 .95 .69 MM5307 4.95 6850 1.95 74HCT27 74HCT244 2.19 12.0 4.95 7415124 2.75 7415377 .79 74HCT30 .69 74HCT245 2.19 6883 22.95 12.480 4.95 Z-80 7415125 .39 7415378 1.18 74HCT32 .79 74HCT257 .99 2.0 MHZ 15.0 4.95 7415126 .39 7415390 1.19 74HCT74 .85 74HCT259 1.59 280 -CPU 25 MK, 1.69 16.0 4.95 68600 4.95 7415132 .39 7415393 .79 74HCT75 .95 74HCT273 2.09 UARTS 18.432 4.95 74LS133 .49 7415541 1.49 74HCT138 1.15 74HCT367 1.09 4.0 MHZ 68602 5.95 20.0 4.95 AY5-1013 3.95 68809E 6.95 7415136 .39 7415624 1.95 74HCT139 1.15 74HCT373 2.49 280A -CPU 1.79 24.0 4.95 7415138 .39 7415640 .99 74HCT154 2.99 74HCT374 2.49 2804-CTC 1.89 Aya -1015 4.95 68809 6.95 TR1602 3.95 68821 3.95 7415139 .39 7415645 .99 74HCT157 .99 74HCT393 1.59 280A -DART 5.95 7415145 .99 7415669 1.29 74HCT158 .99 74HCT4017 2.19 280A -DMA 5.95 2651 4.95 68845 6.95 1M6402 6.95 68850 2.95 7415147 .99 741S670 .89 74HCT161 1.29 74HCT4040 1.59 Z80A-PIO 1.89 MISC. 7415148 .99 7415682 3.20 74HCT164 1.39 74HCT4060 1.49 280A-510,0 5.95 IM6403 9.95 681354 7.95 IN 58250 6.95 TMS99531 9.95 7415151 .39 7415683 3.20 Z80A-510/1 5.95 TMS99532 19.95 7415153 .39 741S684 3.20 Z80A-510/2 5.95 ULN2003 .79 7415154 1.49 7415688 2.40 3242 7 95 7415155 .59 7415783 22.95 8.0 MHZ CLOCK 3341 4.95 7415156 .49 811595 1.49 74F00 Z80B-CPU 3.75 SOUND CHIPS MC3470 1.95 7415157 .35 811596 1.49 74F00 .69 74F74 .79 74F251 1.69 Z80B-CTC 4.25 76477 5.95 CIRCUITS MC3480 8.95 74LS158 .29 811597 1.49 74F02 .69 74F86 .99 74F253 1.69 280B -P10 4.25 76489 8.95 MM5369 1.95 MC 3487 2.95 7415160 .29 811598 1.49 74F04 .79 74F138 1.69 74F257 1.69 Z808 -DART 14.95 551-263 39.95 MM5369-EST 1.95 11C90 19.95 7415161 .39 25152521 2.80 74F08 .69 74F139 1.69 74F280 1.79 180B-SIO/0 12.95 AY3-8910 12.95 MM58167 12.95 2513-001 UP 6.95 7415162 .49 25152569 2.80 74F10 .69 74F157 1.69 74F283 3.95 Z80B-510/2 12.95 AV3-8912 12.95 MM58174 11.95 AV5-2376 11.95 7415163 .39 261531 1.95 74F32 .69 74F240 3.29 74F373 4.29 28671 ZILOG 19.95 SP1000 39.00 MSM5832 2.95 AV5-3600 P8011.95 7415164 .49 261532 1.95 74F64 .89 74F244 3.29 74F374 4.29

Visit our retail store located at 1256 S. Bascom Ave. in San Jose, (408) 947-8881 PLEASE USE YOUR CUSTOMER NUMBER WHEN ORDERING Microdevices TERMS. Min.nun'order 510.03. For shipping and handing include 5250 for UPS JDR lot 1 Ib. Ioregn Ground and 53.50 UPS Air. Orders over and orders may rep 110 Knowles Drive, Los Gatos, CA 95030 additional shipping charges -please conlactoor sales depadneent tor the amount CA residents must include appkcable sales tax. All merchandise is warranted for 90 days 71/.. Toll Free 800-538-5000 (408) 866-6200 unless otherwise staled. Pnces are subtecl to change without nrolice. We ar nut responsible to typographical errors We reserve the nght to 1111111 gnantities and to FAX (408) 378-8927 Telex 171-110 substitute nmanufacturer. All merchandise subject to prior sale. COPYRIGHT 1987 JDR MICRODEVICES THE JDR MICRODEVICES LOGO IS A REGISTERED TRADEMARK OF JDR MICRODEVICES. JDR INSTRUMENTS ANO JDR MICRODEVICES ARE TRADEMARKS OF JUR MIt:ROUE yeCES IBM IS A TRADEMARK OF INTERNATIONAL BUSINESS MACHINES APPLE IS A TRADEMARK OF APPLE COMPUTER. 92 CIRCLE 113 ON FREE INFORMATION CARD EGA CARD AND MONITOR HOW ONLY $569! DISK DRIVES FOR APPLE COMPUTERS CRT MONITORS FOR ALL APPLICATIONS

AP -150 t ¡77 $99.95 11111 !tom 'z HT, DIRECT DRIVE 100% APPLE COMPATIBLE SIX MONTH WARRANTY CASPER CASPER SAMSUNG FORTRONICS EGA MONITOR RGB MONITOR MONDCHROBIE MONOCHROME EGA 8. CGA COMPATIBLE COLOR GREEN AMBER IBM COMPATIBLE TT_ INPUT IBM COMPATIBLE TTL INPUT SCANNING FREQUENCIES SWITCH ON REAR 12" NON -GLARE AMHEF. 12" NON -GLARE SCREEN -J L.) 15 75 21 85 KHz DIGITAL RGB-IBM COMPATIBLE LOW DISTC RTION SCREN VERY HIGH RESOLUTION. AP -135 RES. 640 a 200 350 14" NON -GLARE SCREEN RESOLUTICN 720H 300V 1100 LINES 'CENTER) PITCH, 31mm DOT 25 MHz RESOLUTION 640H a 240V ATTRACT'\ E CASE \JITF 25 MHz BANDWIDTH $129.95 16 COLORS OUT OF 64 39mm DOT PITCH SWIVEL B%SE CABLE FOR IBM PC INCLUDED ) 14", BLACK MATRIX SCREEN CABLE FOR IBM PC INCLUDED ONE YEAR WARRAF TY FULL HT SHUGART MECHANISM AMBER OR BREEN ITIILABIE DIRECT REPLACEMENT FOR APPLE DISX II SIX MONTH WARRANTY $399.95 $299.95 $119.95 $99.95 000etE TILT & SWIVEL MONITOR STAND $1295 WITH POWER CENTER $3995 gum r MAC535 APPLE COMPATIBLE INTERFACE CARDS Seagate $249.95 IIW 3.5" ADD-ON DISK DRIVE 5114" HARD DISK DRIVES 100% MACINTOSH COMPATABLE SI_s. ST -225 HALF HT 20MB 65ms $275 DOUBLE SIDED 800K BYTE STORAGE ST -238 HALF HT 30MB 65ms $299 HIGH RELIABILITY DRIVE IRLL) HAS AUTO -EJECT MECHANISM ST -251 HALF HT 40M8 40ms 5599 FULL ONE YEAR WARRANTY ST -277 HALF HT 60MB 40ms )RLLI CALL EPROM PROGRAMMER 16K RAMCARD IC TEST CARS ST -4038 FULL HT 30MB 40ms $559 ST -4096 FULL HT BOMB 28mns 51195 DUPLICATE OR BURN ANY FULL 2 YEAR WARRANTY QUICKLY TESTS MANY 27.. SERIES EPROM EXPAND YOUR 48K MACHINE OOMMON ICs ` \ 12716 TO 271281 TO O FULL 64K OF MEMORY DISPLAYS PASS OR EVIL AD -3C MENU DRIVEN SOFTWARE CAN BE USED IN PLACE OF TEST 4000 K 74HC SE.IES HIGH SPEED WRITE ALGO THE APPLE LANGUAGE CARD C MOS. 7400, 74LS. 74L. 1/2 HEIGHT FLOPPY DISK DRIVES $139.95 RITHM MA N 74S $3995 51/2" TEAC FD -55B DS DD 5109.95 10096 APPLE Ilc COMPATIBLE, RP -525 $5995 RAM -CARD IC -TESTER 51/2" TEAC FD -55F DS QUAD READY TO PLUG IN WJSHIEIDED 12995 5124.95 CABLE 8 MOLDED 19 PIN 51/2" TEAC FD-55GFV DS HD $154.95 CONNECTOR 51/2" MITSUBISHI D5 HD 5129.95 FAST RELIABLE SLIMLINE DIRECT 31/2' TOSHIBA KIT DS DD 5149.95 DRIVE MOLDED INTERFACE CABLES C. ITOH FIREMAN II PRINTER SIX MONTH WARRANT'S KIT INCLUDES MOUNTING HARDWARE TO 6 FOOT. 100% SHIELDED. MEETS :CC FIT 59" 6 FACEPLATES FOR AT 6 XT DISK DRIVE ACCESSORIES DRIVE FDD CON TROLLER CARD 549.95 DISK ACCESSORIES TEAC SPECIFICATION MANUAL 55.00 Ilc ADAPTOR CABLE $19.95 TEAC MANUAL ADAPTS MAINTENANCE 325.00 STANDARD APPLE DRIVES HT MNTG FOR FOR APPLE HARDWARE IBM 52.95 USE WITH Rc MOUNTING RAILS FOR IBM AT 54.95 "Y" POWER CABLE FOR 5'.' FDD$ 52.95 5'." FOD POWER CONNECTORS 51.19 KB -1000 $79.95 IBM PARALLEL PRINTER CABLE 9.95 160 CPS DRAFT, 32 CPS CASE WITH KEYBOARD CENTRONICS (MALE TO FEMALE) 15.95 NLO 9 . 9 DOT MATRIX FOR APPLE TYPE MOTHERBOARD CENTRONICS (MALE TO MALE) 14.95 DISK DRIVE ENCLOSURES MODEM CABLE IBM) SUPPORTS EPSON IBM GRAPHICS USER DEFINED FUNCTION KEYS (FOR 7.95 FRICTION PIN FEEDS RS232 SERIAL TO AND WITH POWER SUPPLIES NUMERIC KEYPAD W' CUESOR CONTROL (MALE FEMALE) 9.95 VARIABLE UNE SPACING ANC PITCH CAPS LOCK AUTO -REPEAT RS232 SERIAL (MALE TO MALE) 9.95 54995 KEYBOARD EXTENDER ICOILEDI 7.95 CAB -2S05 DUAL SLIMLINE 5'I." APPLE II JOYSTICK EXTENDER 4.95 CA8-IFH5 FULL HT 5`. 569eá CA8-2SV8 DUAL SLIMLINE 8" 120995 219.95 CA8-2FH8 DUAL FULL HT 8" 5P1995 SWITCH BOXES IBM PRINTER CABLE 59.95 ALL LINES SWITCHED GOLD PLATED REPLACEMENT RIBBON CARTRIDGE 57.95 CONNECTORS. OUALI TY SWITCHES 2 WAY $39.95 CONNECTS 2 PRINTERS TO 1 NASHUA DISKETTES COMPUTER OR VICE VERSA NASHUA DISKETTES WERE JUDGEC TO HAVE AB -P (CENTRONICS PARALLEL) THE HIGHEST POLISH AND RECORDEC AMPLITUDE ANY WS (RS232 SERIAL) OF DISKETTES "ESTED KEYBOARD -AP 5 (COMPARING FLOPPY DISKS. BY -E 9 84) REPLACEMENT FOR APPLE II KEYBOARD $.9 N-MD2D DS DD 5 $9.9( CAPS LOCK KEY, AUTO -REPEAT .' SOFT N-MD2F LW QUAD 519.9E ONE KEY ENTRY OF BASIC OR CP M Lb 5'." SOFT COMMANDS 1FJ N-MD2H DS HD 5'." FOR AI 524.9E N-FD1 SS OD 8* SOFT $27.9! N-FD2D DS 8 534.9! DD SOFT BUILD STEVE CIARCIA'S JOYSTICK co-io $19.95 BULK DISKETTE SALE SET X -Y AXIS FOR AUTO CENTER OR 3 WAY $99.95 FREE MOVEMENT CONNECTS 3 PRINTERS T7 1 5'4" SOFT SECTOR, DS DD INTELLIGENT FIRE BUTTON FOR USE WITH GAME COMPUTER OR VICE VERSA W. TYVEC SLEEVES & HUI RINGS SOFTWARE SWITCH -3P (CENTRONICS PARALLEL) EPROM PROGRAMMER ATTRACTIVE, SOLID, PLASTIC CASE INCLUDES ADAPTOR CABLE FOR IBM. SWITCH -3S (RS232 SERIAL) $990 69Cea 59Cea AS SEEN IN BYTE, OCT 86 APPLE II, Ile, II ATARI c. B VIC 20'64 BON OF 10 BULK OTT 50 BUM OTT 251 STAND-ALONE OR RS SERIAL OPERATION MENU SELECTABLE EPROM TYPES NO CONFIGURATION JUMPERS PROGRAMS ALL 5V 27XXX . DISKETTE FILES EPROMS I41 y FROM 2716 TO 27512 51I4' DISIIFILE 31/3 D6NFILE READ. COPY OR VERIFY EPROM HOLDS 70 HOLDS 40 UPLOAD DOWNLOAD INTEL HEX FILES _ IO S8.95 PROGRAMMER DRIVER USER S9 95 MODIFIABLE 3008 MODEM $49.95 FOR APPLE OR 18M INCLUDES ASCII PRO-EI SOFT*ARE FCC APPROVED ONLY$199 POWER STRIP $12.95 BELL SYSTEMS 103 COMPATIBLE INCLUDES AC ADAPTOR .1 KIT INCLUDES PCB AND ALL UL APPROVED t AUTO -DIAL DIRECT CONNECT COMPONENTS EXCEPT CASE 8 154 CIRCUIT BREAKER CABLE FOR APPLE Ilc 514.95 POWER SUPPLY

CALL FOR VOLUME QUOTES COPYRIGHT 1987 JDR MICRODEVICES 93 CIRCLE 182 ON FREE INFORMATION CARD EGA CARD AND MONITOR HOW ONLY $569! QUALITY IBM COMPATIBLE MOTHERBOARDS EASYDATA MODEMS FROM MODULAR CIRCUIT TECHNOLOGY All models feature auto-diallanswerlredial on busy, Hayes compatible, power up sell TURBO 4.77 / 8 MHZ $129.95 test, touchtone or pulse dialing, built-in speaker, PC Talk Ill Communications software, Bell Systems 103 8 212A full or half duplex and more. JDR PART U: MCT-TURBO 4.77 OR 8 MHz OPERATION WITH 8088-2 INTERNAL & OPTIONAL 8087.2 CO -PROCESSOR L DYNAMICALLY ADJUSTS SPEED DURING DISKETTE OPERATION FOR MAXIMUM EASYDATA-12H $99.95 THROUGHPUT AND RELIABILITY 1200 BAUD HALF CARD CHOICE OF NORMAL TURBO MODE OR SOFTWARE SELECT PROCESSOR SPEED EASYDATA-12B $119.95 STANDARD 4.77 MHZ $109.95 1200 BAUD 10" CARD JDR PART U. MCT-XTMB EASYDATA-24B $199.95 8088 CPU. OPTIONAL 8087 CO -PROCESSOR 1 8 EXPANSION ` . 2400 BAUD FULL CARD SLOTS

EXPANDABLE TO 640K ON -BOARD r r G (OK RAM INSTALLED( / EXTERNAL ALLICs SOCKETED -HIGHEST QUALITY PCB 4 /L' 14 ACCEPTS 2764 OR 27128 ROMSMEORY NO .r r I , SOFTWARE INCLUDED BOTH WITH FREE MCT BIOS! EASYDATA-12D $119.95 1200 BAUD EASYDATA-24D $219.95 FARADAY IBM COMPATIBLE 2400 BAUD FDD CONTROLLER FLOPPY DISK DRIVE JDR PART : FAR-FDD JDR PART x: FDD-360 SUPPORTS UP TO 4 INTERNALLY GOOD QUALITY DRIVES DISPLAY CARDS MOUNTED FDOs BY MAJOR MANUFACTURERS SUCH AS IBM COMPATIBLE, INTERFACES TO QUME, TANDON 6 CDC FROM MODULAR CIRCUIT TECHNOLOGY 360K OR 720K USING DOS 3.20 5/" HALF HEIGHT DS/DD INCLUDES CABLE FOR 2 DISK DRIVES 360K STORAGE CAPACITY 48 TPI MCT-EGA $179.95 100M IBM COMPATIBLE, PASSES IBM EGA DIAGNOSTICS COMPATIBLE WITH IBM EGA. COLOR GRAPHICS $24.95 $69.95 AND MONOCHROME ADAPTORS TRIPLE SCANNING FREQUENCY FOR DISPLAY ON EGA. STANDARD RGB OR HIGH RES- OLUTION MONOCHROME MONITOR IBM STYLE FULL 256K OF VIDEO RAM ALLOWS 640 a 350 PIXELS IN 16 OF 64 COLORS BUILD YOUR LIGHT PEN INTERFACE COMPUTER CASE OWN 256K NT AN ATTRACTIVE STEEL CASE WITH COMPATIBLE SYSTEM A HINGED LID. FITS THE POPULAR PC/XT COMPATIBLE MOTHERBOARDS NT MOTHERBOARD $10955 MCT-CG $49.95 COMPATIBLE WITH IBM COLOR GRAPHICS STANDARD PRO -BIOS (A $20 VALUE) FREE! SHORT SLOT CARD USES VLSI CHIPS TO y 258K RAM 82855 INSURE RELIABILITY SUPPORTS ROB. COMPOSITE MONOCHROME 130 WATT POWER SUPPLY 89955 & COLOR AND AN RF MODULATOR OUTPUT 320 x 200 COLOR GRAPHICS MODE SNOyi,tT FLIP -TOP CASE 83455 640 x 200 MONOGRAPHICS MODE LIGHT PEN INTERFACE SLOI 4L KEY TRONIC"KEYBOARD 84995

SWITCH CUT-OUT ON SIDE FOR PC 'XT 380K DRIVE 85995 STYLE POWER SUPPLY MCT-MGP $59.95 CUT-OUT FOR 8 EXPANSION SLOTS FARADAY CONTROLLER 82455 WITH IBM MONOCHROME ALL HARDWARE INCLUDED COMPATIBLE ANO HERCULES GRAPHICS STANDARDS MONOCHROME ADAPTOR 84995 SHORT SLOT CARD USES VLSI CHIPS TO INSURERELIABILITY FORTRONICS MONITOR 89995 PARALLEL I PRINTER PORT, CONFIGURABLE AS li\ liNer4 - LPT1 OR LPT2 mar F. 6011.1 » $34.95 720 x 348 GRAPHICS MODE cl' k MO a TOTAL: $539.15 LOTUS COMPATIBLE SLIDE TYPE CASE $39.95 CAN RUN WITH COLOR GRAPHICS CARD IN 1.01' : THE SAME SYSTEM =w i"

IBM COMPATIBLE KEYBOARDS MCT-MG $79.95 COMPATIBLE WITH IBM MONOCHROME AND HERCULES GRAPHICS STANDARDS SERIAL PORT OPTION PARALLEL PRINTER PORT MCT-5150 $59.95 720 x 348 GRAPHICS MODE ys,. "5150" STYLE KEYBOARD 80 a 25 TEXT MODE FULLY IBM COMPATIBLE LOTUS COMPATIBLE 4. ' i . LEO STATUS INDICATORS FOR CAPS & SELECTABLE TO RUN ALONG WITH COLOR maw*, ITaiiLpYl- NUMBER LOCK GRAPHICS CARD IN THE SAME SYSTEM fc--` . LARGE, EASY TO REACH SHIFT & MG S1995 RETURN KEYS -SERIAL OPTIONAL SERIAL PORT 83 KEY TYPEWRITER LAYOUT MCT-MONO MCT-5151 $79.95 $49.95 III II IL yJLU U ANOTHER FANTASTIC VALUE FROM JDR! REPLACEMENT FOR KEY TRONIC" IBM COMPATIBLE TTL INPUT KO -5151 KEYBOARD 720.348 PIXEL DISPLAY PLEASE NOTE THIS CARD WILL NOT RUN LOTUS GRAPHICS SEPARATE CURSOR & NUMERIC KEYPAD AND DOES NOT INCLUDE A PARALLEL PORT CAPS LOCK & NUMBER LOCK INDICATORS IMPROVED KEYBOARD LAYOUT EPROM PROGRAMMERS MCT-5060 $59.95 FROM IBM AT STYLE LAYOUT MODULAR CIRCUIT TECHNOLOGY SOFTWARE AUTOSENSE FOR XT OR AT COMPATIBLES MCT-EPROM EXTRA LARGE SHIFT & RETURN KEYS $129.95 LED INDICATORS FOR SCROLL, CAPS & PROGRAMS 27xx AND 27xxx SERIES EPROMS UP TO 27512 NUMBER LOCK SUPPORTS VARIOUS MANUFACTURERS AUTO REPEAT FEATURE FORMATS WITH 12.5, 21 AND 25 VOLT PROGRAMMIMO MENU -DRIVEN SOFTWARE ALLOWS 11111111111 EASY MANIPULATION OF DATA FILES MCT-5339 $89.95 SPLIT OR COMBINE THE CONTENTS OF IBM ENHANCED STYLE LAYOUT SEVERAL EPROMS OF DIFFERENT SIZES SOFTWARE AUTOSENSE FOR XT OR AT READ. WRITE. COPY, CHECK AND Gr..L.13 ERASE u EAU.] CUM kW~I COMPATIBLES VERIFY WITH EASY ONE KEY SELECTION 12 FUNCTION KEYS INCLUDES SOFTWARE FOR STANDARD . EXTRA LARGE SHIFT & RETURN KEYS HEX AND INTEL HEX FORMATS 1q../q- LED INDICATORS FOR SCROLL. CAPS & ll.-- NUMBER LOCK 4 GANG PROGRAMMER 818995 S4_ r AUTO REPEAT FEATURE SEPARATE CURSOR PAD 10 GANG PROGRAMMER 229995

MCT COPYRIGHT 1987 JDR MICRODEVICES 94 PRODUCTS CARRY A ONE YEAR WARRANTY CIRCLE 183 ON FREE INFORMATION CARD 12008 MODEM $9995 FOR IBM E/ . 2400B MODEM $19995 MULTIFUNCTION CARDS FROM MODULAR CIRCUIT TECHNOLOGY MCT-MF $79.95 ALL THE FEATURES OF AST'S SIX PACK PLUS AT HALF THE PRICE! Seagate 0.348K DYNAMIC RAM USING 4164s INCLUDES SERIAL PORT, PARALLEL Sr PORT, GAME CONTROLLER PORT AND CLOCK/CALENDAR SOFTWARE FOR A RAMDISK. PRINT SPOOLER HARD DISK SYSTEMS AND CLOCK/CALENDAR

MCT-ATMF $139.95 20 MB 30 MB ADDS UP TO 3 MB OF 1 BIT RAM TO THE AT USER EXPANDABLE TO 1.5 MB OF ON -BOARD -Y MEMORY INO MEMORY INSTALLED) r FLEXIBLE ADDRESS CONFIGURATION I I , INCLUDES SERIAL PORT. PARALLEL PORT AND $339 $399 CLOCK/CALENDAR Systems include half height hard disk drive, hard disk drive controller, OPTIONAL PIGGYBACK BOARD PERMITS EXPANSION TO 3 MB cable! and instructior s. Drives are pre -tested and warranted for one year. 4eJn`^-, - ATMF-SERIAL 2nd SERIAL PORT 52495 MCT-ATMF-MC 52995 PIGGYBACK BOARD (ZERO K INSTALLED) MB AT DRIVE MCT-MID $79.95 &9Seagate40 A PERFECT COMPANION FOR OUR MOTHERBOARD FAST 4Oms ACCESS TIME . 2 DRIVE FLOPPY DISK CONTROLLER INCLUDES SERIAL PORT, PARALLEL PORT. -L -,. GAME PORT AND CLOCK/CALENDAR t-,4 WITH BATTERY BACK-UP s.5 SOFTWARE FOR A RAMDISK, PRINT SPOOLER 1 AND CLOCK CALENDAR 112 IGHT - HE MIO-SERIAL 2nd SERIAL PORT 51595 Iy'W 19\11\N\ $599 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 COMA PARALLEL PRINTER PORT ADDRESSABLE AS FROM NODULAR CIRCUIT TECHNOLOGY LPT1 OT LPT71.378 OR .2781 ot CLOCK/CALENDAR WITH A 5\\011 MCT-FDC BATTERY BACK-UP w.714 $34.95 I0 -SERIAL 2nd SERIAL PORT 51595 ---AuS`ó` QUALITY DESI 3N OFFf RS 4 FLOPPY CONTROL IN A SINGLE SLOT IN-ERFACES UP TO a FDDs TC AN IBM IN* i Oho. PC OR COMPATIBLE P4+*. INCLUDES FOR , CABLING 2IN-ERNAI MCT-ATIO $59.95 DRIVES CT TL USES STANDARD ECTOR. BLOT USE WITH MCT-ATFH FOR A MINIMUM OF SLOTS USEC FOR EXTERNAL DRI9CONNEE 1.. SERIAL PORT ADDRESSABLE AS COM1, COM2, SUPPORTS BOTH DS DO ANC DS/Q - COM3 OR COMA - W BEN USED W. DOS 3.2 OR. FORMAT PARALLEL PRINTER PORT ADDRESSABLE AS LPTA OR LPTB (.378 OR .278) GAME PORT SHORt USES 16450 SERIAL SUPPORTCHIPS FOR HIGH SLOT. a MCI-HDC $89.95 SPEED OPERATION IN AN AT :H,,1111%.11 HARD DISK CONTROL FOR WHAT OTHERS CHARGE FOR FLOPPY CONTROL ATTO -SERIAL 2nd SERIAL PORT 52495 1KM XT COMPATIBLE CONTROLLER SUPPORTS 16 DRIVE SIZES INCLUDING Iyy,S\z . 5. 10, 20, 30840M OPTIONS INCLUDE THE ABIUTY TO CIVIDE 1 LARGE DRIVE INTC 2 RAM CARDS SMALLER. LOGICAL DRIVES INCLUDES CABLING FOR 1 INTERNAL FROM MODULAR CIRCUIT TECHNOLOGY DR VE MCT-RAM $69.95 MCT-RLL /VI\ y A CONTIGUOUS MEMORY SOLUTION FOR YOUR SHORT OR REGULAR SLOT $119.95 GET UP TO 50% MORE STORAGE SPACE ON YOUR HARD DISK SHORT SLOT, LOW POWER PC COMPATIBLE wee.-...-...... I. DESIGN INCREASES THE CNPACITY )F PLATED CAN OFFER UP TO 576K OF ADDITIONAL MEDIA DRIVES BY 50% ALL 2,7 ENCODING FOR MOTE MEMORY 1 W RT I.n Fy1141..4 USER SELECTABLE CONFIGURATION RELIABLE STORAC E UN. , AMOUNTS OF 192. 384. 512. 256 & 576K, SS0T _ .A.a TRANSFER RATE IT ALSO 5.5. FASTER: USING COMBINATIONS OF 64 & 256K RAM 750K 'sec vs 500K 'sec USE WITH ST -238 )RIVE TC ACHIEVE 30 MB IN A HALF HEIGHT SLOT MCT-ATRAM $149.95 A POWER USERS DREAM. 4MB OF MEMORY FOR THE AT MCI-FH $139.95 USER EXPANDABLE TO 2MB OF ON -BOARD STARVES FOR SL' TS? SATISFY IT WITH THIS TIMELY DESIGN MEMORY F t) ITV rT?V-1J~ "t-1 INTERFACES UP 0 2 FDD & 2 HDDs USES FULL 16 BIT PARITY CHECKED MEMORY, I. CABLING FOR 2 F3Ds & 1 NDD . w . 64K OR 256K DYNAMIC RAM -- 1 ' , FLOPPY INTERFA. E FLEXIBLE ADDRESS, SUPPORTS BOTH o STARTING ROUND OUT DS DD & DS OD WHEN USED WITH CONVENTIONAL MEMORY TO 640K & ADD , ", - '11 ' 4 dlya G MEMORY ABOVE 1MB DOS 3.2 OR JFORMAT F pp EXTENDED - ALL POPULAR T :llty ` e HC D SIZES >RE +r.KM or, MCT-ATRAM-MC 53995 t SUPPORTED. INCLUDING v.10.20.309. 2r4;* b 2MB PIGGYBACK BOARD (ZERO K INSTALLED) 40MB CAN DIVIDE 1 LARGE DRI-IE INTO 2 SMALLER. LOGICAL DRIVES MCT-EMS $129.95 2MB OF LOTUS/INTEL/MICROSOFT COMPATIBLE MEMORY FOR THE XT MCT-ATFH CONFORMS TO LOTUS. INTEL EMS $169.95 USER EXPANDABLE TO 2MB .l.A X-..--rc cr 294 a FLOPF Y AND F ARO DISK CONTROL IN A TRUE AT DESIGN sue- le ?,-,, USES 64K OR 256K DYNAMIC RAM -° AT -. N as COMPATIBLE COSTA 31 UP TO 2 WI,. r7n (NO MEMORY INSTALLED) ^__I°I.+. ,s-k+ - s, 360K 720K OR -.2MB F. AS WELL - ss1.99 USE AS EXPANDED OR CONVENTIONAL w *- Y'^^ _ AS 2 HDOs USING THE AI STANDARD -. MEMORY, RAMDISK OR SPOOLER Zr- CONTROL TABLES r 1 SOFTWARE INCLUDES EMS DEVICE DRIVERS. CS - SUPPORTS AT STYLE FRCNT PANEL , PRINT SPOOLER AND RAMDISK LED TO INDICA -E HO ACTIVITY 16 BIT BUSS PR )VIDES F APID DATA MI,`TNG-LELC', TRANSFERS L 0. .F- MCT-ATEMS AT VERSION OF THE MCT-EMS 513995 FULLY SUPPORTED BY Al BIOS

110 Knowles Drive, Los Gatos, CA 95030 JDR Mic rodevices Toll Free 800.538-5000. 408 86S-6200 FAX (408)378-8927 Telex 171-110 I THE JOR MICRODEVICES LOGO IS A REGISTERED TRADEMARK OF JDR MICRODEVICES. J61 INSTRUMENTS AND JON NICRODE VICES ARE TRADEMARKS OF JOR MICRODEVICES IBM ISA TRADEMARK OF INTERNATIONAL BUSINESS MACHINES. 95 CIRCLE 184 ON FREE INFORMATION CARD 12008 MODEM $9995 FUMY 2400B MODEM $19995 PAGE WIRE WRAP WIRE WIRE WRAP PROTOTYPE CARDS BARGAIN HUNTERS CORNER PRECUT ASSORTMENT FR -4 EPDXY GLASS LAMINATE IN ASSORTED COLORS 527.50 WITH GOLD-PLATED EDGE -CARD FINGERS NEW FROM RIM ELECTRONICS

500ea: 3.0". 3.5". 4.0" 0)t SPOOLS 100 feet 54.30 250 feet 97.25 NICKEL 0095 500 foot 913.25 1000 feet 521.95 Please specify color: EMPRESS Blue, Black. Yellow or Rad IBM-PR2 EXTENDER CARDS IBM IBM-PC $29.95 BOTH CARDS HAVE SILK SCREENED LEGENDS PC/XT SPEED UP KIT AND INCLUDES MOUNTING BRACKET IBM -AT $39.95 INCREASE THE SPEED OF YOUR PC BY 67% OR MORE! IBM-PRI WITH 5V AND GROUND PLANE . 527.95 SIMPLE NO -SLOT INSTALLATION IBM-PR2 AS ABOVE WITH DECODING LAYOUT 529.95 SOFTWARE OR HARDWARE SPEED SELECTION S-100 * 8 MHz V20 PROCESSOR & SOFTWARE INCLUDED P100.1 BARE - NO FOIL PADS 515.15 SELECT FOR 3 TURBO FREQUENCIES P100.2 HORIZONTAL BUS 521.80 RESET u P100-3 VERTICAL BUS 52'.80 * EXTERNAL SWITCH 522.75 OPTIONAL 8088 8 MHz PROCESSOR AVAILABLE 9 P100.4 SINGLE FOIL PADS PER HOLE Certain eerty PCs may net run en 8 MHz-tr.ese mech.ns may be synched to ens d the slower speeds. APPLE 6.66 MHz 40% 7.37 MH5=56% 80 MHz 67% I I P500.1 BARE - NO FOIL PADS 515.15 . P500-3 HORIZONTAL BUS 52275 P500-4 SINGLE FOIL PADS PER HOLE 521.80 SPECIAL ENDS 7/31/87 7060-45 FOR APPLE Ile AUX SLOT 530 00

SOCKET -WRAP IDTM 1.0 FRAME STYLE SWITCHING POWER SUPPLIES 2 IC SLIPS OVER WIRE WRAP PINS TRANSFORMERS IDENTIFIES PIN NUMBERS ON WRAP I- P R SIDE OF BOARD 's 12.6V AC CT 2 AMP 5.95 P8 -IBM $89.95 CAN WRITE ON PLASTIC; SUCH AS IC O 4 IBM PC -XT COMPATIBLE 'd U 12.6V AC CT AMP 7.95 FOR PINS PARTO PCK. OF PRICE ui 12.6V AC CT 8 AMP 10.95 135 WATTS 8 IDWRAP08 10 1.95 v 25.2V AC CT 2 AMP 7.95 5V Ir 15A. 12V ( 4.2A 14 IDWRAP 14 10 1.95 -5V @ .5A. -12V @ .5A 16 IDWRAP 16 10 1.95 e ONE YEAR WARRANTY 18 IDWRAP 18 5 1.95 ~ PS -IBM 150 20 IDWRAP 20 5 1.95 ^ 25 PIN D -SUB 22 IDWRAP22 5 1.95 24 IDWRAP 24 5 1.95 n GENDER P8 -IBM -150 $79.95 28 IDWRAP 28 5 1.95 FOR IBM PC -XT COMPATIBLE 40 IDWRAP40 5 1.95 CHANGERS - ,,.r..-' 150 WATTS PLEASE ORDER BY NUMBER OF ID WRAP 24 PACKAGES (PCK. OF) $7.95 12V @ 5.2A. -5V @ 16A [email protected],[email protected] ONE YEAR WARRANTY CAPACITORS DATARASE EPROM ERASER $34.95 PS -130 ERASES 2 IN 10 MINUTES P8-130 $99.95 TANTALUM COMPACT-NO DRAWER ~1~ 1.Opl 15V .35 .47,4 35V .45 THIN METAL SHUTTER 130 WATTS 6.8 15V .70 1.0 35V .45 PREVENTS UV LIGHT Will SWITCH ON REAR 10 15V .80 2.2 35V .65 FROM ESCAPING FOR USE IN OTHER IBM 22 15V 1.35 4.7 35V .85 TYPE MACHINES (2 .40 10 1.00 G. -ow- .22 35V 35V 90 DAY WA RRANTY 9 F DISC 1/4 WATT RESISTORS lOPt 50V .05 680 50V .05 5% CARBON FILM ALL STANDARD VALUES PS -A $49.95 22 50V .05 .001r4 50V .05 PS 27 50V .05 .0022 50V .05 FROM 1 OHM TO 10 MEG. OHM USE TO POWER APPLE TYPE -A ry 33 50V .05 .005 50V .05 10 PCS san .rem .05 100 PCS sarna value .02 SYSTEMS, '9.5 WATTS LLL 50 PCS sine Aid. .025 1000 PCS san value .015 47 50V .05 .01 50V .07 -5V C 7A. -12V @ 3A 68 50V .05 .02 50V .07 -5V @ .5A. -12V (ríá .SA t r 100 50V .05 .05 .07 ) 50V APPLE POWER CONNECTOR 220 50V .05 .1 12V .10 560 50V .05 .1 50V .12 nit. RESISTOR NETWORKS rag SIP 10 PIN 9 RESISTOR .69 P8-1558 $34.95 MONOLITHIC 8 PIN 7 RESISTOR .59 SIP 75 WATTS. UL APPROVED w. Rje .01rÁ 50V .14 .101 50V .18 16 PS 1558 r's1f 50V .15 .4701 50V .25 DIP PIN 8 RESISTOR 1.09 @ @ ' .0470 5V 7A. 12V 3A !wad TN IT DIP 16 PIN 15 RESISTOR 1.09 -12V @ 250rle. -5V @ 300ma ELECTROLYTIC DIP 14 PIN 7 RESISTOR .99 RADIAL AXIAL DIP 14 PIN 13 RESISTOR .99 101 25V .14 101 50V .14 BY STEVE 2.2 35V .15 10 50V .16 BOOKS CIARCIA MUFFIN FANS 4.7 50V .15 22 16V .14 3.15" SO 14.95 3.63" SQ 14.95 BIULO YOUR CWN 3.18" SQUARE 16.95 10 50V .15 47 50V .20 Z80 COMPU-ER 519.95 47 35V .18 100 35V .25 SPECIALS ON BYPASS CAPACITORS 100 16V .18 220 25V .30 .01 pf CERAMIC DISC 100/55.00 CIRCUIT CELLAR VOL 1 517.95 6' LINE CORDS 220 35V .20 470 50V .50 .01 pf MONOLITHIC 100/510.00 CIRCUIT CELLAR VOL 2 518.95 2 conductor .39 3 conductor .99 470 25V .30 1000 16V .60 VOL 3 518.95 3 conductor w female socket 1.49 .1 pf CERAMIC DISC CIRCUIT CELLAR 2200 16V .70 2200 16V .70 100/56.50 CIRCUIT CELLAR VOL 4 518.95 4700 25V 1.45 4700 16V 1.25 .1 pf MONOLITHIC 100/512.50 CIRCUIT CELLAR VOL 5 519.95 EMI FILTER $4.95

WISH SOLDERLESS BREADBOARDS LITHIUM BATTERY VOLUME SET AS USED IN CLOCK CIRCUITS 2 PART DIMENSIONS ¡DISTRIBUTION TIE TERMINAL I TIE BINDING-PRICE STRIPS) POINTS STRIPS) iPOINTS¡ POSTS NUMBER I

WBU D .38 6.SÓ} 1 100 ... _. » 2 95 IC MASTER 1 6 95 WBU T 1 38 a 6 50"- ¡-- --- 630 L. --- THE INDUSTRY STANDARD WBU 204.3 3 94 a 8 45"--1 1 100 2 1 1260 ¡ 2 17 95 WBU 204 5 13 a8 45" 4 400 2_1 1260 r 3 24 95 I 1890 4 29.95 IWBU-206 6.88 a 9 06" 5 500 3 ` 3 VOL- BATTERY 53.95 8.25 e 7 700 4 2520 ! 4 39.95 51.49 WBU-208 9.45" 1 WBU-208 BATTERY HOLDER $129.95

Visit our retail store located at 1256 S. Bascom Ave. in San Jose, (408) 947-8881 PLEASE USE YOUR CUSTOMER NUMBER WHEN ORDERING TERMS-. Minanun order 51000 For shipping and handing include 52.50 for UPS Microdevices 53.50 loe UPS AIn. Orders over 1 Ib and tolegn orders may rebuke JDR Ground and 110 Knowles Drive, Los Gatos, CA 95030 additional shrpprg charges -please contact our sales depadrnent for Meanounl. CA 4111 residents must include applicable sales tae. All merchandisers warranted for 90 days Toll Free 800-538-5000 (408) 866-6200 unless otherwise staled Peces are subeecl lo change without notice. We am nol responsible tot ly-lographeral errors We reserve Me nght to bmil buanblres and to FAX (408)'378-8927. Telex 171-110 subsbtule manufacturer. All merchandise subjecl to poor sale. COPYRIGHT 1987 JDR MICRODEVICES THE JON MICRODEVICES LOGO IS A REGISTERED TRADEMARK OF JDR MICRODEVICES. JDR INSTRUMENTS AND JON MICRODEVICES ARE TRADEMARKS OF JOR MICRODE VICES. IBM IS A TRADEMARK OF INTERNATIONAL BUSINESS MACHINES. APPLE IS A TRADEMARK OF APPLE COMPUTER. 96 CIRCLE 185 ON FREE INFORMATION CARD Radie Ihaek Parts PIaee`" THE BUILDER'S STORE! OVER 1000 COMPONENTS IN STOCK

Communications Attention -Getting LEDs Save With Our "Hotline'.., Circuit Book Order Service 11/9 1¡ We send your order r (2) f h directly to the brad wet 's )á Radio near you. 149 Mas Nutebnn4 1 Shack We pay the postage. A Must [(4) Delivery time on most For Project items Is one week. Builders ri 1, Your Radio Shack store The latest of (1) Super -Bright Red. Outputs manager can special -order

the "hands- 300 mcd, 20 mA. #276-066, 1.19 a variety of parts and Sc- - on" electronic - (2) Blinking Red. MOS driver and cessories not listed in our project books by Forrest M. Mims red LED combo. #276-036 .. 1.29 catalog-tubes, linear and Ill. Includes projects for wired and digital ICs, diodes, transis- / wireless voice and code systems. (3) Blinking Green. tors, crystals, phono cartridges and more. There's no shortwave listening and much #276-030 1 29 minimum order requirement 'or this convenient ser- more. Contains 48 pages with (4) CdS Photocell. Abated 200 vice! Your order will be sent to your nearby Radio schematics. #276-5015 mW 170 volts. #276-116 .... 1.79 Shack store, and we'll notify you when it arrives. Unusual Buzzers Panel Switch Values Put These High -Tech ICs to Work

-. 1 (8) (9) (6) ' ,1Sa taa aaa u , , (12)

59c Low As ' Each Maximum Capacity In an Extremely 49c ' Upgrade Small Package Each Your Computer fr IC pin spacing. 20% tolerance. 4164 64K Dynamic RAM. 150 ns Vented steel tops, easy -to -work Rated at ' e -watt. Sealed against F WVDC Cat No. Each access time, low -power design noise contaminants. (230 mW, typical). Single 5 VDC aluminum chasis. With protective -causing 0.1 35 272-1432 49 rubber feet and hardware. supply. #276-2506 3 95 Ohms Cat. No. 047 35 272-1433 .49 1.0 35 272-1434 49 TMS 4256 256K Dynamic RAM. Size Cat. No. Each 1k 271-333 150 ns maximum access, low - 2.2 35 272-1435 59 3'/a x 2'/e x 4" 270-251 2.99 10k 271-335 power t6 -pin DIP with specs and 10 16 272-1436 .69 4 x 23/e x 6" 270-252 3.99 25k 271-336 pin -out. Single 5 VDC supply. 22 16 272-1437 .99 5'/a x 3 x 5'/e" 270-253 4.99 100k 271-338 #276-1252 6 95 Archer Hand Tools Archer' Coax b 28 -Range FET VOM_ Dual -Tracking DC Supply ::r:: - (13) ' 4995 ! 4'- Low As Big 5" , (14) )(1(15) 160 Color - per foot Coded j= 11::11 = Professional Quality Scale Low loss-no more than 4.0 dB per (13) 5'/a" Long Nose Pliers. 100 feet at 50 MHz. Spring return, insulated grips. Delivers stable DC with extremely RG Vel. Cat. Price low ripple at precisely the voltage #64-1812 . 5 99 Type Ohms Fact. No. Per Ft. you need. Adjustable from 0 to 15 (14) 41/2" Diagonal Cutters. like a VDC, 52 66°/o 278-1323 .36 Works solid-state VTVM! or series output provides up Spring return, long lasting and in- 8 input to 30 VDC. Selectable independent 8 52 75% 278-1328 .21 Super-sensitive-10-megohm sulated grips. #64-1813 .... 5.99 of two voltages. 58 52 66% 278.1326 .16 impedance. With 28 ranges and or slave operation (15) 6" Locking Forceps. Use as Includes test Meter for monitoring voltage or cur- 59 75 75% 278-1327 .16 "beep" continuity. a temporary heat sink and to pick leads and spare fuse. Requires one rent of either output. UL listed. up or hold parts. #64-1866 .. 4.95 'NEW! 95% Shielding. 9V and one "C" battery. #22-220. #22-121 69.95

Over 1000 items in stock: Binding posts, Books, Breadboards, Buzzers, Capacitors, Chokes, Clips, Connectors, Fuses, Hardware, ICs, Jacks, Knobs, Lamps, Memory nacho lhack Chips, Multitesters, PC Boards, Plugs, Power Supplies, Rectifiers, Relays, Resis- A DIVISION OF TANDY CORPORATION tors, Switches, Tools, Transformers, Transistors, Wire, Zener Diodes, more! Prices appl, at partcipating Radio Snack stores and dealers

CIRCLE 78 ON FREE INFORMATION CARD

97 *QUALITY PARTS*DISCOUNT PRICES * FAST SHIPPING! SEI v G. P Pc1 ISOR 4' , '1 LIGHT ACTIVATED SOUND EFFECTS BOARD MICRO -CASSETTE MECHANISM PC board with 2 1/4" speaker, SPRING LEVER MOTION SENSOR 2 LEDs, IC, battery snap, Micro -cassette tape transport for other components 2 3/6"x 3". standard MC60 or MC45 When switch micro 3 TERMINALS This device is pushed -cassettes. Vdc operation. board beeps and leds light .,. Contains: drive motor. belt, head. Two color contains a 1 Operates on 9v battery cap Stan p inch wheel and other coded Qa yhotocell components 3 1/2' X 2 1 4' X 5 8' terminals on a e (not included) iii III which seises CATS MCMEC each 10 stuMy2M' 53.00 for $27.50 sudden Changes Exr'-rirrenter's delights 348- bakeee CAT. ST -3 51.25 ea. plate. in ambient light. Great for spea er enclosures or EDGE When an object Or person COMMODORE PRINTER PLOTTER 2K 10 TURN power supplie passes within it's field 754 EACH 10 for $6.00 Commodore Model a 1520 CONNECTORS MULTI -TURN POT of view (about 5'1 it beeps 4 inch Four color X -V plotter. Standard VIC for several then paper ALL ARE .156' SPACING. AM00534.4 seconds resets. serial interface allows easy conneCtein FUSES +'1 Could be used as a door annun- to Commodore 64 computers. DD to 60 $5.00 EACH ciator or modified to trigger 3AG (AGO SIZE characters per line. other devices. 5 1/2" x 4" x I. arrrnnrT 7111TIIIInIIr- 1.11 2 21. 3, 4. 5,6AMP RELAYS operates on 6 vdc. Requires 4 AA 22 EDGE CONNECTOR $1.25 as GMA SIZE CAT e COM-1520 1. 2 3 4. 5 AMP batteries (not included). solder lug style 101o, 10 AMP SOLID STATE $49.95 each 011.00 5 of any ONE amperage 754 CAT. LSMD 55.75 per unit 22/44 EDGE CONNECTOR EXTRA pen sets $1.50 per set. :ON IROL: 3-32 vdc ea PC style 10 $2.00 for $18.00 LOAD: 140 vac 10 amp' 22/44 EDGE CONNECTOR WE 21' i:.n- ey PHOTO -FLASH MINIATURE TOGGLE D.PS.T. LIGHTED SWITCHES ROCKER SWITCH solder lug style 52.50 each ,it CAPACITORS ALL ARE RATED 5 AMPS @ 125 VAC $9.50 EACH 10. FOR $90.00 t 115 vac lighted rocker 28/56 EDGE CONNECTOR { 170 MFD 330 Volt in snap mounts P.0 style $2.50 ea ULTRA -MINIATURE If CAT: PPC-170 S.PD.T. S.PD.T. S.PO T. 0. .1'S hole 75c each (on -on) (on -on) (on -off -on) Orange lens 16 amp 36/72 EDGE CONNECTOR 5VDC RELAYFujit PC PC style Solder lug Solder lug contact style $3.00 each u n $1.50 FBR211 NED005M20 400 MFD 330 Volt non -threaded terminals terminals 43/66 EDGE CONNECTOR 51.00 ea bushing $1.00 each 51.00 each BUTTON sensitivity CAT. PPC-400 MINI -PUSH PC style 54.50 COIL 120 onms 750 each 10 for 59.00 Ie 10 for $9.00 each S PS.T momentary - CONTACTS: tamp 10ío, $ 7.00 100 for $80.00 100 for 580.00 normally open Mounts in 14 pn DIP socket V,- bushing. WALL COMPUTER GRADE S.PD.T. $1.25 each 10 for $10.00 S.PD.T. D.RD.T. Red buttons 101or53 TRANSFORMER -on) 00 CAPACITORS (on -off -on) (on (on -on) MINIATURE PC lugs 11.5 Vdc 6 VDC RELAY 1,400 mfd. 200 Vdc PC style threaded Solder lug SNAP ACTION 3" X 2" dia. 52.00 non threaded terminals 1.95 Aromar 0RSD-6V bushing L' bushing 51.00 each $2.00 each r, SWITCH SuperPD. Small d Vdc 754 each 10 for 519.00 611, Amp. S relay 6,400 mf 60 10 for $9.00 Q11h1 3/e" 101or 5700 too for 580.00 100 for $180.00 Cherry elect. rt-21 N O. or N.C. GO40W 4 1/4"xl dia.52.5u INPUT: rated 0 16 contacts Suitable for alarms contacts 120 Vac 1 amp vdc. Highly sensitive. 7,500 mfd 200 Vdc other low energy circuits SIZE: @ 30 and TTL direct drive possible. 120 ohm 5 3,4" x 3" dia. 54.00 CARLING LED'S 1St' lever X 2 7/8" X 2 5/8" S.P.S.T. STANDARD JUMBO 3 3/4" cod, 12,000 Vdc (on -off) 454 EACH 10 FOR $4.20 CAT M DCTX-11519 Operate from 4.3- 6 vdc. mfd 40 TOGGLE RATED: DIFFUSED T 1-3/4 $6.50 each COIL: 120 ohms $1.50 each 4 1/4" x 2" dia. 52,50 SWITCH 10 amp RED 10 WALL 1i/,40 "JD-Ar/,r 10 for $13.50 P 125 Vac. too loo, n1$13.005$3l.00 22,000 mfd 25 Vdc 10 for TRANSFORMERS All plastic body GREEN $2.00 TRANSFORMERS 13 VDC RELAY 4 3/4" x 2" dia. 52.50 100 for $1700 and toggle. all directly YELLOW 10 for $2.00 plug CONTACTS S PN.0 Ir9^ 48,000 mfd 10 Vdc 100 for $1000 into 120 vac y 120 volt vac CAT. STS -1 t0amp@t20 -L outlet primaries Energize coil to 3" x 2 1/2" dia. $2.50 51.00 ea. FLASHER LED 4VDC®70 ma. 52.00 open contact 10 for $8.50 6 VAC 6500ma. 53.50 5.6 volt. 4( 750 ma. 13.00 COIL: 13 vdc 650 ohms 66,000 mfd 15 Vdc 100 for $7.50 6 VDC g 750 ma. 54.50 T von Operation 6.3 volt h boo m.. $1.75 1 5 9 VDC 500 me. $5.00 SPECIAL PRICE 51.00 each 3 3/4" x 3" dia. 53.50 LARGE QUANTITIES ® 12 VC.T re 200 me. 52.00 red lambo!ti. size 12.5 VAC 265 me. $3.00 6 12 v.C.T i 400 ma. 53.00 to VAC to VA and 4PDT i1t 72,000 mfd 15 Vdc CAT*LEO-4 $1.00 42 RELAY XENON FLASH TUBE 12 v.OT t 1 .wp 54.00 4" x 9.5 VAC h 1.20 VA $3.50 14 pin KH e. 2" dia. 53.60 12 V.C.T. i 2 amp 54.85 NEW GREEN FLASHER 24 VAC CI 250 ma. $3.00 3 amp contacts 12 V.CT 4 amp 100,000 CAT LED -1G 5100 MULTI -VOLTAGE fs 500 ma. u 52.00 USED but fully mfd 10 Vdc 111 le robs 4 650 ma. 3,4" long X 1,8" dia Flash 3,41/2,6,714,9 or 12 VDC 5750 52.00 tested $1.70 each 6" x 2 1/2" ua.ai.0u BI lumbolt5 24 V.C.T. a 200 ma. $2.50 Specify tube designed for use in -POLAR s0e coil voltage desired 24 V.C.T. 1 amp saes camera flash units TRANSISTORS 4 Either 24 vdc or 120 vac Compact 24 V.CT a 2 amp $6.75 3rd TAIL Idea for LED HOLDERS 2N706 LARGE QUANTITIES AVAILABLE experimentors. 41or 01.00 24 V.C.T. ii 3 amp $9.50 -1 2 Two piece holder 8 2N2222A FOR LIGHT ? CATS FLT for 51.00 3 for $1.00 4 SOCKETS KM RELAY tor bo LED PN2222A 24 V.C.T. 4i amp $11.00 Sleek lu 4 1or $1.00 750 each t010r 654 10010, 55.00 2N2904 3 for $1.00 high-tech 2N2905 lamp CLEAR CLIPLITE 31or $1.00 48 KEY ASSEMBLY 1422955 51.50 TI SWITCHING POWER SUPPLY assembly. LED HOLDER 2N3055 51.00 Compact. well.rngulated switching power FOR COMPUTER OR LEDED a supply Could be PMD 10K40 $1.00 designed to power Texas Instruments dke Clear computer used as a TIP 121 754 equipment HOBBYIST 4 for $1.00 TIP 125 third auto 754 INPUT. t4-25 vac tampamp* SPECIAL tail light, emergency OUTPUT:. 12 vdc 550 ma. PRICE 5 vdc@@ 1.2 amp warning light, or WE'VE MOVED $3.50 special -effects lamp. - 5 vdc 200 ma. 414- each Red reflective lens Our Mall Ord Operation SIZE x 41/4- x 114- high is 2 3/4" x 5 1/2" to serve U better is mounted on a 13.8 VDC REGULATED POWER SUPPLY NEW T.I. KEYBOARDS Ongna y NEW 4" high pedestal = These are solid state, fully regulated 13.8 vac used on Computers, these keyy supplies. with up -down swivel MAILING ADDRESS rrmnar power Bath feature 100% solid state boards Contain 48 S P S T.mech- --- construction, fuse protection, and L.E.D. power adjustment. Includes anical switches. Terminates to P.O. BOX 567 mditetor U L. listed. 12v replaceable bulb. 15 pn Connector. Frame 4" x S- 2 amp constant, 4 amp surge $20.00 each CATO each. - TLB 53.95 CAT A KP-48 53.50 each VAN NUYS, CA 91408 --Q amp constant, 5 amp surge $2750 each TELEPHONE SOUND AND VIDEO RECHARGEABLE NI -CAD 8" 15 WATT SPEAKER COUPLING MODULATOR NI -CAD BATTERIES CHARGER C.T.S Model 883079 TIUM13e1-1 Designed for use with TESTER Full range speaker. TRANSFORMER T.I. computers. Can be used with Will charge 100.10,000Hz: video cameras, games or other most every Ideal for PA systems. (4 bronco, TTPC.8 audio/video sources. Built in A/B size a. ' Mounting holes ror AAA SIZE 1.25V $1.85 `... switch enables user to switch from Ni -Cad line -matching transformer 600 ohms c t to 600 ohms C t AA SIZE 1 25V 500mAH T.V. antenna without disconnection. $1.85 battery P.C. mount AA with solder tab $2.00 :-'A hoard Channel 3 or 4 seletion. Operates on CATASK-615 3l4" . . C SIZE 12V 1200mAH available. 518" 3H' 12 Vdc. Hook-up diagram included. $3.50 SUB -C SIZE solder lab $3.50 53.50 ea. Case of e pc.. CAT. AVMOD 55.00 each. 51.25 each D SIZE I 2V 1200mAH $3.50 Cate UNCC-N 512.50 $25.00 per case POLARITY SWITCH SOLID f STORES MEW MAIL ORDERS TO: OUANTITIES LIMITED external coaxial relay onnaa STATE LOS ANGELES, CA VISA ALL MINIMUM ORDERS 110.04 TOLL FREE ORDERS satellite TV system. IDEAL FOR GiSi ELECTRONICS CALIF. ADD SALES TAX 905 S. Vermont Ave. P.O. 800-826-5432 THE EXPERIMENTOR AS PARTS/.. BUZZER BOX 567 USA: $3.00 SHIPPING 213 380-8000 Heavy chassis box containing a Star eSMB-061. 91408 NO C.O.D.! ¡l® INFO (213) 380-8000 6 vac VAN NUYS, CA FOREIGN ORDERS: CA 358 op amp)) TWX - 101010163 TTL compatible. 6228 Sepulveda Blvd. INCLUDE SUFFICIENT and other parts. Catalog I RDPS FAX - (213) 389-7073 ALL ELECTRONIC SHIPPING $1.00 each 818 997-1806 51.75 each 10 for 515.00 10 for $8.00 98 CIRCLE 107 ON FREE INFORMATION CARD What's New at "The Source" of the electro -mechanical components AMERICAN DESIGN COMPONENTS? I'D, the hobbyist. e warehouse 60.000 P C 8300 31/2 -, 10Mb 5%4", 1.2 Mb. AT 15- GUMPUSI I t items at American H OME COMPUTER HARD DISK DRIVE HALF HT. DISK DRIVE VIDEO MONITOR IA dvanced version (IBM1 Compatible) yam. - Design Components - ex- of the Timex 10001 - - ---.. pensive, often hard -to -find components for sale at a 1.., fraction of their original cost! You'll find every part you ti' need - either brand new, ....S Y. , 1 5", green phosphor, high reso- or removed from equipment Fit3 standard 5'/. " spacing. 48/96 TPI fr 2 10s center) band - Shock mounted. High speed. low (IBM1 Compatible) t0and (RFE) in excellent condition. widthlott from t2o /242 3 3dB. power. Mfr - Rodime #R0252F Double sided, sin le/rouble 4 ?-key mechanical keyboard (not g Ope g volt.:v65V AC, But quantities are limited. y y Item #10151 $ 1 New density; 80 track. embrane). Contains 2K of 59.00 50/60Hz.. 65VÁ max. Controller for above Mfr - Panasonic #JU-475 Mfr Motorola - Alpha Series Order from this ad, or visit R I.M. Reverse video, Z80Á, Card - 6. Item #10150 $ Item #10005 $119.00 New Item #10044 $ New our retail showroom and find SMHz processor, ROM 8K 89.00 34.95 BASIC. Graphics capabilitylsound- 5j 14 5% " Insides the exactly what you need from usic, TV or monitor. Joystick of FULL : di, -,:ii-' 1/2 HT. ithe thousands of items on put operates on 115 VAC. In- 'ri Commodore Computer cl tides: AC adapter, TV cable, HT. # DISK -- . t;;,1y :+/1áp1° ¡-r display. an d pair of cassette cables. Will DISK -' DRIVE -.j1 i.:., - ru n all prerecorded tapes for Sin- r DRIVES 1, ,i - Open Mon. - Sat., 9-5 cl air/Timex 1000-ZX81. Mfr - -_ r - fr. P ower 3000. In orig. boxes. 48 TPI `-t " Ileem #10336 $29.95 New (IBM© Compat.) THERE'S NO RISK. a_ Accessories . . . Double With our full 90 -day warranty, sided/double density, full - I. ' 48 purchase * 16K RAMPACK upgrade height drive. T.P.I., 80 tracks. any can be returned for Mfr - Tandon TM100.2 i It em #10337 New 1-Li1+ItI IltltIlliLI IL any reason for full credit or refund. $9.95 DOS t Item #7928 $79.95 3.2 Compatible - * 32K RAMPACK upgrade 96 TPI, DS/QUAD DENSITY 2 for $ 1 50.00 Commodore VIC 20 CPU board & ADAM COMPUTER. * It em #12148 $19.95 New Tandon TM55-4 DS/Quad 96 TPI, Density mechanical keyboard. Guaranteed ptl!11IÍ1IIÍtIil11it1N+nn`.. * COLOR PACK Mfr -CDC #94097 Item #1904 $ 79.00 not to work. (For pans only.) I1! Itt im #12147 DISK * $19.95 New Item #1893 $99.00 2 for S 150.00 Item #12144 $14.95 RFE DRIVE 1 2", High Resolution SWITCHING POWER COMPUTER GRADE HI -POWER * TL MONITOR SUPPLY POWER SUPPLY SWITCHING * ..,<.--'_1 11, POWER SUPPLY

* /: r __'-. a t. , tY ¡I

.... -. t ... - @ t`_ -, . Gives your Adam fast, reliable data Output: +5.15V @ 70A storage and retrieval. Can hold up to 115&230V,47-440/ Hz. + +12V@4A f) +'.1 160K bytes of information. Uses industry- Input: 90 -135V/180 -270V Other uses -runs C9 & ear radios. ..-12V @ 4A standard SS/DD disks. Connects directly 41 _, ... Output: 5VDC @ 5.5A Comes nerdy to Meg in! .5.2V @ 5A 1; 1 2VDC @ .4A DC 115/230V to your Adam memory console. Comes ? VDC/110 VAC (w/built-in' Output: - 5V @ .5 amp. Input: nominal, @ with disk drive power supply, Disk pt twer supply). Green phosphor. -12VDC .3A +5V @ 3 amp. .725KW cont. 47-63Hz. En - metal Manager disk and owner's manual. M td. in metal housing. Schematic Perforated case enclosure. + 12V @ 6 amp, closed in metal housing. Dim.: 9%"L x 3%"W x Input 15"W x Mfr - Coleco, Model 7817 sc applied. Mfr - Capetronic 2'H. 115V/60H. Dim.: 9r/ 'W Dim.: 2%"H x 6" deep. #1 Iilr)S-1030; Mfr - General Instrument x 3% "H. (Rubber It. incl.) Mfr - Todd Prod. #4XS8151A Item #12830 $ New 199.00 item #6811 519.95 New Item #7881 $14.95 New hem #41n1 S24 95 No- Item #8748 529.95 New, ADAM Accessories.. , PUMPS- COMPRESSORS- BLOWERS- MOTORS -POTENTIOMETERS- COUNTERS ADAM COMPUTER KIT - TIMERS -RELAYS -VOLTAGE REGULATORS ILess printer.) Includes: Keyboard, digital -POWER SUPPUES data drive. 2 game Controllers, power sup- 1 -PIECE JOYSTICK 12/24 VDC AT -STYLE ply, all memory boards, and one cassette. TELE- CONTROLLERS No wiring necessary; hook-up diagram incl. MUFFIN- COMPUTER II PHONE TYPE Item #7410 $99.00 -11/1- CABINET t COLECOVISION to ADAM FANS -.. EXPANSION KIT - Touch- Plugs into your ColecoVision. With printer tone to power supply & one data drive. you'll have a rotary (may 55/100 CFM working Adam Computer' Keyboard & one be used Basic 8 W. Can be mounted for blow- Smart cassette also included. even where r_ ing or exhaust. 4119r_ r ; 2.11 Item #9918 $59.50 there is Aiuminum hous- only ing, brushless, bad -bearing type. Contains 10 full-length ADAM PRINTER - a rotary 1" Thin: 5 plastic expan- blades with sion Item #8839 $69.50 phone). feathered edges. slots (w guides). With room for an internal 51/." hard DATA DRIVE Features: last number redial & Mfr - Centaur #CUDC24K4.6O1 disk - Fits Atari, Apple. Commodore, drive. Has 3 half Item #6641 mute button. Comes w 15" cord -height disk drive & standard modular plug. and our #10336 PC8300 Com- Item #8541 S 19.95 New slots. Rear on/off LAST CHANCE - $19.95 switch, notched Color: Ivory. Mfr - Spectra phone puter. Has 4 -ft. cord with plug. 11/2" Standard- 5 plastic blades to hold in power supply (not Model OP -1. Item #10748 Dim.: 3Y," sq. x1 %" H. Mfr - PRINTER POWER SUPPLY - Centaur #CNDC24K4 601 incl 1, and security switch w/key. Item #6642 $14.95 $6.95; 3 for $15.00 New Item #12143 $5.95 New Item #12109 $14.95 RFE Item #12266 $49.95 New ASCII KEYBOARD - AMERICAN DESIGN COMPONENTS, 62 JOSEPH STREET, MOONACHIE, N.J. 07074 Item #6643 $19.95 MINIMUM YES! Please send mg the following items: _ My check or money order is enclosed ORDER CONTROLLERS - Item How $15 (Set of 4) Item #7013 $9.95 Charge my credit card. No. Many? Description Price Total RE -87 ADAM CASSETTES - Visa ' Master Card - Amex IConsisting of Smart Basic, Buck Rogers Card No. & blank cassette.) ------E.p Date --- Item #7786 Í i L BAKER'S DOZEN - $19.95 Signature LOGIC BOARD - Telephone Area Code Number (Parts only.) Item #7231 $9.95 Total Name GAME BOARD - Shipping & handling, we ship UPS unless (Parts only.) Item #7679 $6.95 otherwise specified. Add $3 plus 10% total. - Address FiS,(( Canadian: $3 plus P.O. cost. Charge only. ADAM LINK MODEM - City )Software included.) CAT4; 1987` Sales Tax (N.J. residents only, with please Item #12353 $29.95 en,ó / add totall State Zip TOTAL AUTO -DIALER rcl'r ORDER All rngurries and free catalog requests call 201-939.2710. ADDRESS BOOK - Item #12365 $19.95 For all phone orders, call TOLL -FREE 800-524-0809. In New Jersey, 201-939-2710. CIRCLE 195 ON FREE INFORMATION CARD 99 THIS 45 SQ. INCH "77W51,:: - ADVERTISING INDEX IS LIGHT PANEL .035 RADIO -ELECTRONICS does not assume any responsibility for errors that may appear INCH THICK PRODUCES.' in the index below. NO HEAT COMES IN 3 BOLD COLORS HAS IT'S ". OWN 12 VOLT POWER Free Information Number Page 191 O('TE Electronics 79 SUPPLY AND THATS ~a I ID Omnilrun 31 WHY WE CALL ITS. 81 A.I.S. Satellite 79 Pacific 83 THE iffatelle 1118 NI(' Sales 29 Cable

181 Parts Express 84 They were developed by the computer industry' 1(17 All Electronics 98 as L.C.D. You can and hi-tec backlights. bend twist 103 Allen W.It 38 1111 1'ununla Electronics CV4 'them into almost any shape, The white one turns 78 Radio Shack 97 a brillant colbolt blue, The pink one turns bright - Amazing 1levices 1(X) white, The green one, well it looks like the power 195 American Design Conywnents 99 177, 178 Sencore 21.23 source from a space ship! A manual explains how I 1811 27 they work and the assembly directions are clear. 98 Heckman Industrial 3 179, Sencore 25. Even the solder is included! 85 Blue Star Industries 78 186 Silicon Valley Surplus 100 EACH 339 KIT INCLUDES: 86 I:INSTRUCTION MANUAL WITH THEORY SECTION 109 C&SSales 14 74 Solid State Sales SEND 15 (APPLIED TO PURCHASE) FOR THE MANUAL ONLY 94 Star Circuits 79 5:LIGHT PANELS: - C.O.\I.11 16 I EA 10 INCH BY 4.5 INCH (SPECIFY WHITE OR BLUE) 92 611 CIE 34 Tektronix CV2 IEA 9.5 INCH BY 2.5 INCH (PINK THAT TURNS WHITE) I 66 W.S..Ienks 26 3EA 9.5 INCH BY 2.5 INCH (MELT DOWN GREEN) 89 Cameo Fnkrprises 79 I:POWER SUPPLY KIT 54 Chemlronies 93

115 DAY DIODEY BACK TRIRL I 196. 198 Circuit Cellar 78. 79 Call for a cops of 15 dal trial agreement. Tex & frei,ht extra.Send check or add 1,90 for COD. - Command Productions 29 Price mes chenae.Store Price may dilfer.While supplies last. No POs, terms, or credit cards_ 203 Computer Technologies 72 OPEN SiliconValleySurplus 10em- 6pm 194 Cook's Institute 24 415-261-4506 CLOSED 4401 OAKPORT OAKLAND CA, 94601 SUN &MON 193 C rystek 8

CALL OUR BBS 4 1 5-261 -45I 3 2181 Uaclron 12 CIRCLE 186 ON FREE INFORMATION CARD Gernsback Publications, Inc. 127 Deco Industries 78. 79 500-B Bi-County Blvd.

189. 1911 Dick Smith Electronics 90 Farmingdale, NY 11735 (516) 293.3000 82 Uigi-hey 87 President: Larry Steckler Vice President: Cathy Steckler - Electronic Technology Today . 78. 79 CV3

12(1 Elephant Llectronics 24 For Advertising ONLY 516-293-3000 AMAZING III Elronix 81 Larry Steckler publisher SCIENTIFIC & ELECTRONIC lilll Fireslik II 29 Arline Fishman advertising director 188 First Street Computer 26 PRODUCTS Shelli Weinman PLANS -Bolo Yourself -Al Pans AvailaUe In Stoc - Hirrdham Radio 10 advertising associate LC7-BURNING CUTTING CO, LASER S 20.00 Lisa Strassman RU6.I-PORTABLE LASER RAY PISTOL 20.00 - Grantham College of Engineering 9 credit manager TCC1-3 SEPARATE TESLA COIL

PLANS 101 5 MEV . . .. 20 00 Christina Estrada 86. 176 Il eat h 9 2(1 IOGT-ION RAY GUN . .. . 1000 advertising assistant GRA1-GRAVITY GENERATOR 1000 1(S EML1-ELECTRO MAGNET COIL GUN/LAUNCHER 6.00 - 81 SALES OFFICES KITS 65 J & 3V is

MFTTK-FM VOICE TRANSMITTER 3 MI RANGE . 49 50 VWPM5K-TELEPHONE TRANSMITTER 391 RANGE 39.50 EAST/SOUTHEAST 59 .11)K Instruments 7 BEY -250.00 VOLT 10-14' SPARK TESLA COIL . 199 50 Stanley Levitan LHC2K-SIMULATED MULTICOLOR LASER.. 39.50 113, 182 .11)K Eastern Sales Manager BLSTK-100.000 WATT BLASTER DEFENSE DEVICE . 6950 Illicrodevices 92. 93 ITMTK-100.000 VOLT 20' AFFECTIVE Radio -Electronics RANGE INTIMIDATOR 69 50 183, 184 .113R Micrudevices 94. 95 259-23 57th Avenue PSP4K-TIME WAVE PISTOL 50 VARIANT SHOCK 59 Little Neck, NY 11362 PTGIK-SPECTACULAR PLASMA 185 .11)14 Micrudevices 96 TORNADO GENERATOR. 149.50 718-428.6037, 516.293.3000 MVPIK SEE IN DARK KIT ... .. 169.50 114 .Iameco 88. 89 ASSEMBLED MIDWEST/Texas/Arkansas/ PG701-MULTICOLORED VARIABLE 1(14 .Ian Crystals 13 Okla. MODE PLASMA GLOBE "7" . 425 00 Ralph BTC10-50.000 VOLT -WORLDS SMALLEST Bergen 87 MCM Electronics 91 TESLA COIL 44 50 Midwest Sales Manager LGU40-1MW HeNe VISIBLE RED LASER GUN 29950 Radio -Electronics AUTO TELEPHONE RECORDING 24 50 204 MI) Electronics 79 TAT20 DEVICE 540 Frontage Road -Suite 339 GPVTO-SEE IN TOTAL DARKNESS IR VIEWER 299 50 LISTIO-SNOOPER PHONE INFINITY TRANSMITTER 169.50 93 Mark N. Electronics 85 Northfield, IL 60093 IPG70-IPVISIBLE PAIN FIELD GENERAT OR - 312-446-1444 MULTI MODE ...... 74.50 2(15 Mercer 11

DESCRIPTIONS OF ABOVE PLUS PACIFIC Mountain CATALOG CONTAINING 61 Microprocessors Unitd. 72 COAST/ HUNDREDS MORE AVAILABLE FOR S1.00 OR INCLUDED FREE States WITH ALL ABOVE ORDERS - Nkl I I. 17 Marvin Green PLEASE INCLUDE 53 00 PH ON ALL KITS AND PRODUCTS Pacific Sales Manager MO. VISA. MC IN PLANS ARE POSTAGE PAID. SEND CHECK. 187 NTS 79 US FUNDS Radio -Electronics 15335 Morrison St. -Suite 227 Nesda 28 INFORMATION UNLIMITED - Sherman Oaks, CA 91403 P.O. BOX 716 DEPT.RE, AMHERST, NH 03031 2)12 is ("Scope Associates 72 818-986-2001

100 Ñ ÑQ Ñ Ñ Ñ 1 N / N N Ñ(lppll cÑ(yD Npp Ñp7 Np Np tNp Ñ N N N Ñ FOR FREE 111/111-111,11,11111:1111 (((y(y (p ( INFORMATION (pp( ,, yy N y p (pyl EO o USE THESE Z m22g221,222g22g8222 ñ ñ POST-PAID 212 i$ ió (ó 2 ñ ñ ñ ñ Z iº ñ iii CARDS v 4 á é é l(i in í >r ít) liri l iñ í^n l°ñ 2 lé in ló Ñ N N 8 M c'f 2 A M 2 f'f r°I v á Ó á V

In N C7 < lA OD /. CO 0) 1 Print your name, ad- Ñ Ñ Ñ N dress and Zip Code on u 82888528g2262 one of the attached °n° ñ 8 m22g2 `co iá i$ 8 á) postage -paid cards. 8132iag2iS1iBiónññ 2 Circle the number (or c%) á{{p4.444442.7,1,'2I ppp p, pp (y y l D numbers) on the card N Ñ Ñ N lV N Ñ C1 P7 (7 2 (7 f`') C 1 that matches the O O N f7 Q lA number at the bottom of each ad or editorial item that you want information on. Advertisers' free information numbers also NO POSTAGE appear in the ad index NECESSARY on the facing page. IF MAILED IN THE UNITED STATES 3 Mail the card. It's Postage -Paid. BUSINESS REPLY MAIL The bottom free -informa- FIRST CLASS PERMIT NO 597 BOULDER. COLORADO tion card is a BUSINESS/ PROFESSIONAL CARD. If you use this card you MUST Italic complete the spaces for Company Name, Title, and Electronics. Phone Number. If these are SUBSCRIPTION SERVICE not filled in, the card will not P.O. Box 51866 be processed. BOULDER, COLORADO 80321-1866

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BP125-25 SIMPLE AMATEUR BAND ANTENNAS 55.00. All are inexpensive [3 BP33-ELECTRONIC CALCULATOR USERS HANDBOOK 55.75. Invaluable to build, yet perform well. Diodes, beams, triangle and even a mini rhombic. book for all calculator owners. Tells how to get the most out of your calculator.

[1 BP128-.20 PROGRAMS FOR THE ZX SPECTRUM AND 16K ZX82 55.75. [ ] BP36-50 CIRCUITS USING GERMANIUM, SILICON 8 ZENER DI- Included with each program is a flow chart and a description of what happens. ODES 55.00. A collection of useful circuits you'll want in your library. Notes for converting programs for use on otner computers are also included. BP37-50 PROJECTS USING RELAYS, SCR'S & TRIACS 55.00. Build pri- o 160-COIL DESIGN 8 CONSTRUCTION MANUAL 55.95. How the hobbyist ority indicators, light modulators, warning devices, light dimmers and more. can build RF, IF. audio and power coils, chokes and transformers. Covers AM FM and TV applications. f l BP183-AN INTRODUCTION TO CP/M 55.75. To run and use programs operating under the CP M operating system you will find this book extremely useful.

C-1 208-PRACTICAL STEREO 8 OUADROPHONY HANDBOOK 53.00. A reference book for all interested in stereo and multichannel sound reproduction. n BP42-SIMPLE LED CIRCUITS $5.00. A large selection of simple applications for this simple electronic component. BP99-MINI-MATRIX BOARD PROJECTS 55.00. Here are 20 useful circuits that can be built on a mini -matrix board that is just 24 holes by ten copper-foil s:rips. [I BP127-HOW TO DESIGN ELECTRONIC PROJECTS 55.75. Helps the reader to put protects together from standard circuit blocks with a minimum of trial and BPt57-HOW TO WRITE ZX SPECTRUM AND SPECTRUM GAMES PRO- error. GRAMS 55.95. A crystal-clear step-by-step guide to writing your own graphics games programs. [ ; BP122-AUDIO AMPLIFIER CONSTRUCTION 55.75. Construction details for preamps and power amplifiers up through a 100 -watt DC -coupled FED amplifier.

BP117-PRACTICAL ELECTRONIC BUILDING BLOCKS-Book 1 55.75. Oscillators, Timers, Noise Generators, Rectifiers, Comparators. Triggers and more. BP92-CRYSTAL SET CONSTRUCTION 55.00. Everything you need to know about building crystal radio receivers.

CT 219-SOLID-STATE NOVELTY PROJECTS 54.95. Fun projects include the BP45-PROJECTS IN OPTOELECTRONICS 55.00. Includes infra -red detec- Optomin, a musical instrument that is played by reflecting a light beam with your light hand, and many more. tors, transmitters. modulated transmission and photographic applications. O BP179-ELECTRONIC CIRCUITS FOR THE COMPUTER CONTROL OF 8P48-ELECTRONIC PROJECTS FOR BEGINNERS 55.00. A wide range of ROBOTS 55.00. Data and circuits for interfcing the computer to the robot's easily completed protects for the beg nner. Includes some no -soldering protects. motors and sensors. BP49-POPULAR ELECTRONIC PROJECTS $5.50. Radio, audio. household [1 BP126-BASIC 8 PASCAL IN PARALLEL 54.95. Takes these two program- and test equipment protects are all included. ming languages and develops programs in both languages simultaneously.

BP51-ELECTRONIC MUSIC AND CREATIVE TAPE RECORDING 55.50. [1 224-50 CMOS IC PROJECTS 55.25. Includes sections on multwibrators, Shows how you can make electronic music at home with the simplest and most amplifiers and oscillators, trigger devices, and special devices. inexpensive equipment.

225-A PRACTICAL INTRODUCTION TO DIGITAL IC'S 54.95. Mainly concerned with TTL devices. Includes several simple projects plus a logic circuit test BP56-ELECTRONIC SECURITY DEVICES S5.00. Includes both simple and set and a digital counter timer. more sophisticated burglar alarm circuits using light, infra -red, and ultrasonics.

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n 227-BEGINNERS GUIDE TO BUILDING ELECTRONIC PROJECTS.._.55.00. BP72-A MICROPROCESSOR PRIMER 55.00. We start by designing a small How to tackle the practical side of electronics so you can successfully build how electronic projects. computer and show we can overcome its shortcomings.

BP169-HOW TO GET YOUR COMPUTER PROGRAMS RUNNING 55.95. BP74-ELECTRONIC MUSIC PROJECTS 55.95. Provides the experimenter Shows how to identify error in program and what to do about them. with a variety of practical circuits incl Jding a Fuzz Box, Sustain Unit, Reverberation Unit, Tremelo Generator and more. 123-FIRST BOOK OF PRACTICAL ELECTRONIC PROJECTS 53.75. Prot- ects include audio distortion meter, super FET receiver, guitar amplifier, metronome i 1 BP91-AN INTRODUCTION TO RADIO DXING 55.00. How you can tune in on and more. those amateur and commercial broadcasts from around the world in the comfort of your home. BP24-52 PROJECTS USING IC 741 55.25. Lots of protects built around this one available IC. BP94-ELECTRONIC PROJECTS FOR CARS AND BOATS $5.00. Fifteen BP110-HOW TO GET YOUR ELECTRONIC PROJECTS WORKING $5.00. simple protects that you can use wan your car or boat. All are designed to operate How to find and solve the common problems that can occur when building protects. from 12 -volt DC supplies.

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