Now You Can Enjoy HI-FI Remote Sound WITHOUT RUNNING WIRES AROUND the HOUSE

JANUAR 976 , 75c Po War Electronics WORLD'S LARGEST - SELLING ELECTRONICS MAGAZINE

A FIRST Now You Can Enjoy HI-FI Remote Sound WITHOUT RUNNING WIRES AROUND THE HOUSE

PROJECTS: Build a Digital Stopclock Voltmeter Measures to Beyond 20 MHz

FEATURES: How to Use CB Radio "Buzz" Words Introduction to Radio Astronomy

TEST REPORTS: BIC Belt - Drive Record Changer Pickering Stereo Phono Preamp hlhçç MW S,lCdë3N`.,. 3S C1 Tram AM CB Mobile Transceiver 10 53N0't88A7 r hiAND

6[Ndf 01h0 Heath Color Organ 6b0e9901 3Ni ng906h _ ..+a-'. __á-' K...... a.

www.americanradiohistory.com e dolit just talkWe build quality. That's why Cobra CB radios are engineered arid built to operate at peak performance under all conditions. BO we don't stop there. Our concern for quality assures you of performance that makes using your CB more enjoyable. And our dealers and distributors are concerned about customer service. All this - because, like you, we're serious about CB. quality

Products of Dynascan

1801 W. Belle Plaine Ave., Chicago, Illinois 60613 (312) 327 -7270

CIRCLE NO. 13 ON FREE INFORMATION CARO

www.americanradiohistory.com Remember when a good dual trace scope cost less than $500? It does again. Model 1471 Dual Trace Oscilloscope 10 MHz Bandwidth - useable to 15 MHz $495 Mode automatically shifts between CHOP and As the B &K- Precision Model 1471 rolls back the ALTERNATE as you change sweep time economic calendar, it significantly advances per- Bright blue P31 phosphor formance capabilities of 10MHz oscilloscopes. 18 calibrated sweeps -1 µSEC /cm to .5SEC /cm Model 1471 shares many of the performance and Sweep to 200nSEC /cm with 5X magnification convenience features of our higher priced scopes, benefiting from Dynascan's position as a leading Maintains calibration accuracy over supplier of medium oandpass scopes. 105- 130VAC range Front panel X -Y operation using matched Deflection factor is 0.01V /cm to 20V /cm in 11 vertical amps ranges. Model 1471 has 18 calibrated sweeps - 1µSEC / cm to .5SEC / cm and sweep to 200n- Input grounding switches SEC/cm with 5x magnification. Regulation main- TV sync separators tains calibration accuracy from 105 to 13OVAC. Check most digita logic circuitry including CMOS Rise time is 35nSEC. Automatic triggering is ob- Character display applications using TTL tained on waveforms with as little as 1cm deflec- Z -axis intensity modulation tion. Dual trace display mode automatically shifts BNC connectors between CHOP and ALTERNATE as sweep time is changed, speeding set -up. In -Stock Free Trial Model 1471, or any B &K- Precision oscilloscope, Front panel X -Y operation uses matched vertical can be obtained from your local distributor-or amplifiers, preserving full calibration accuracy for call Dynascan. You'll find the scope you need in both amplitude and phase. The intensity modula- stock today. Write for detailed specifications. tion input (Z axis) is compatible with TTL, permitting use in character display systems, and for time or frequency markers. Bright blue P31 phosphor makes any waveform easy to see. Circuit board with plug connectors permit easy user maintenance. BNC connectors. Operates on 117/230 - PRODUCTS OF ,DYNASCAN VAC 50 /60Hz. 1801 W. Belle Plaine Chicago, Illinois 60613

CIRCLE NO 9 ON FREE INFORMATION CARD 1 JANUARY 1976

www.americanradiohistory.com ALTA R 4K's

NEW ALTAIR 1/O CARDS

The price of the ALTAIR 4K memory boards from MITS was incorrectly listed at $264 in the "MITS -MAS" Christmas Catalog printed in December's Popular Electronics. Unfortunately, the price change came after the catalog was printed.

The ALTAIR 4K hoard provides 4,096 words (bytes) of dynamic RAM (Random Access Memory) for the ALTAIR 8800. Each individual hoard contains memory protect circuitry and address Two new ALTAIR 8800 I/O boards are now in production. 16 in selection circuitry for any one of starting address locations These include a serial interface (88 -2510) that can be ordered increments of 4K. The maximum access time of the ALTAIR 4K with one or two ports, and a parallel interface (88 -PIO) that can board was recently reduced from 300 nanoseconds to be ordered with up to four ports. 200 nanoseconds. Each port of the new Serial interface board is user-selectable Dynamic memory was chosen for the ALTAIR 4K hoard because for RS232, TTL, or 20 milliamp current loop (Teletype). The it is generally faster and requires less current than static memory 88 -2510 with two ports can interface two serial I/O devices, each (a 4K static card that meets ALTAIR bus drive specifications running at a different baud rate and each using a different elec- requires close to three times the 5 volt current of dynamic trical interconnect. For example, the 88 -2510 could be interfaced memory). to an RS232 CRT terminal running at 9600 baud and a Teletype Other ALTAIR 8800 memory options include a 1K (1,024 words) running at 110 baud. and a 2K (2,048 words) static memory card. These low power An on- board, crystal -controlled clock allows each port to be static memory cards contain memory protect features and have set for one of 12 baud rates: 37.5, 75, 110, 150, 300, 450, 600, a maximum access time of 850 nanoseconds. 1200, 1800, 2400, 4800, or 9600. Baud rates are the speed at which data is transfered between the computer and the I/O device. ALTAIR 8800 Memory Prices: 4K Dynamic $195 kit and $275 assembled Each port of the new Parallel interface provides 16 data lines 2K Static_ $145 kit and $195 assembled and four controllable interrupt lines. Each of the data lines can 1K Static $ 97 kit and $139 assembled be used as an input or output so that a single port can interface a terminal requiring 8 lines in and 8 lines out -or it can interface two input devices such as a paper tape reader and a keyboard - as a tape and Prices. delivery and specifications subject to change. or two output devices such paper punch printer - or any combination for custom applications. All data lines are fully TTL compatible.

ALTAIR 8800 Interface Prices: 88 -2510 Serial Interface $115 kit and $144 assembled 88 -SP additional 88 -2510 port $ 24 kit and $ 35 assembled 88 -4P10 Parallel Interface with one "Creative Ele( mill( S port $ 86 kit and $112 assembled MITS /6328 Linn N.E., Albuquerque, NM 87108 505/262-1951 88 -PP additional 88 -4P10 port $ 30 kit and $ 39 assembled

2 CIRCLE NO. 34 ON FREE INFORMATION CARD POPULAR ELECTRONICS

www.americanradiohistory.com JANUARY 1976 VOLUME 9, NUMBER 1 Popular Electronics® WORLD'S LARGEST SELLING ELECTRONICS MAGAZINE FEATURE ARTICLES AN INTRODUCTION TO RADIO ASTRONOMY David Heiserman 41 A simple telescope system will get you into a fascinating new hobby. I2L -A NEW TRANSISTOR LOGIC FAMILY William D. Haffner 56 Provides high speed and low power requirements. ENVELOPE GENERATORS & SEQUENCERS FOR ELECTRONIC MUSIC Don Lancaster 58 Shaping tones or notes and determining combinations or order.

CONSTRUCTION ARTICLES A WIRELESS AUDIO SYSTEM FOR REMOTE SPEAKERS Jim Sherwin 35 High -quality remote sound without running wires. BUILD A $25 HIGH -FREQUENCY VOLTMETER Thomas H. Sear 46 Measures up to 90 volts from dc to beyond 20 MHz. A DIGITAL STOPCLOCK FOR SHORT & LONG EVENT TIMING Michael S. Robbins 48 Times to 10 hours in 0.1- second intervals. THE PROGRAMMABLE MUSIC BOX, PART 2 Mitchell Waite & Larry Brown 53 Adding a 256 -word memory and programming notes.

COLUMNS STEREO SCENE Art Salsberg 18 Audio Potpourri. SOLID STATE Lou Garner 79 Prophecies for Next Year. TEST EQUIPMENT SCENE Leslie Solomon 83 Making Good Use of Noise. COMPUTER BITS Jerry Ogdin 88 Interrupts & Real -Time. CB SCENE Sherman P. Wantz 91 How to Use CB Radio "Buzz" Words. ART'S TV SHOP Art Margolis 93 The Bewildering Brightness. AMATEUR RADIO Herbert S. Brier 96 Using Slow -Scan TV. HOBBY SCENE Q & A John McVeigh 98 EXPERIMENTER'S CORNER Forrest Mims 101 Using an Optoisolator.

PRODUCT TEST REPORTS

BIC MODEL 980 MULTIPLE PLAY MANUAL RECORD PLAYER 68 PICKERING MODEL PP -1 PHONO PREAMPLIFIER 69 TRAM XL AM CB TRANSCEIVER 70 HEATHKIT MODEL TD -1006 4- CHANNEL COLOR ORGAN KIT 72 SENCORE MODEL CR31 CRT TESTER & RESTORER 73 DEPARTMENTS EDITORIAL Art Salsberg 4 Buzz Words & OEM Distributors. LETTERS 6 NEW PRODUCTS 12 NEW LITERATURE 16 ELECTRONICS LIBRARY 99 OPERATION ASSIST 100 ADVERTISERS INDEX 119

POPULAR ELECTRONICS, January 1976. Volume 9. Number 1. Pub- Ziff -Davis also publishes Boat ng. Car and Driver, Cycle. Flying. Modern lished monthly at One Park Avenue, New York, NY 10016. One year sub- Bride, Popular Photography, S

scription rate for U -S., $6.98; U.S. Possessions and Canada. $7.98; all Editorial correspondence: POPULAR ELECTRONICS. 1 Park Ave.. New other countries. $8.98. Second Class postage paid at New York. NY and at York, NY 10016. Editorial contr butions must be accompanied by return additional mailing offices. Authorized as second class mail by the Post postage and will be handled with reasonable care; however, publisher Office Department, Ottawa. Canada and for payment of postage in cash. assumes no responsibility for return or safety of manuscripts, art work, or Subscription service and Forms 3579; P.O. Box 2774, Boulder. CO 80302. models. POPULAR ELECTRONICS including ELECTRONICS WORLD, Trade Forms 3579 and all subscription correspondence: POPULAR ELEC- Mark Registered. Indexed in the Reader's Guide to Periodical Literature. TRONICS, Circulation Dept.. P.J. Box 2774, Boulder. CO 80302. Please COPYRIGHT 1975 BY ZIFF -DAVIS PUBLISHING COMPANY. ALL allow at least eight weeks for change of address. Include your old address. RIGHTS RESERVED. enclosing. if possible. an address label from a recent issue. JANUARY 1976 3

www.americanradiohistory.com Popular Electronics

EDGAR W. HOPPER

Publish, , ARTHUR P. SALSBERG Editorial Director LESLIE SOLOMON Editorial Technical Editor

JOHN R. RIGGS Managing Editor

ALEXANDER W. BURAWA Feature Editor

EDWARD I. BUXBAUM BUZZ WORDS & OEM DISTRIBUTORS Art Director

JOHN McVEIGH in fields can drive Assistant Editor Esoteric expressions used by people special "out" groups up the wall. The latter often view such jargon as an exercise in ANDRE DUZANT Technical Illustrator pretentiousness. And in some cases, this is true. Usually, however, buzz words favored by the "in" people represent easy shortcuts to quick PATRICIA BROWN Editorial Assistant communication.

LOU GARNER For example, what audiophile would use the term "intermodulation GLENN HAUSER distortion "? It's "IM," of course. Does an electronics experimenter talk JULIAN D. HIRSCH RALPH HODGES about "100 picofarards "? Nonsense! It's "100 puffs." Hams, too, have buzz ART MARGOLIS words that mark them as cognoscenti, as do other groups such as CB'ers. FORREST MIMS JERRY OGDIN In fact, a list of buzz words for the latter is included in this issue to ease WILFRED M. SCHERER the entry pains for CB newcomers. Contributing Editors You don't have to be an expert to use buzz words successfully. A recent JOSEPH E. HALLORAN on the lives of prominent women pointed out that Claire Booth Advertising Director article Luce (her husband founded Time, you recall) used buzz words effectively JOHN J. CORTON Advertising Sales in many fields to reinforce the authoritativeness of her assertions. There's a host of microprocessor buzz words that have touched our LINDA BLUM Advertising Service Manager sensibilities recently. Schweber Electronics just published a glossary of these new words. It's called "Microprocessor Buzz Words" and is an PEGI McENEANEY Executive Assistant interesting compilation, with words such as "port" -the microprocessor's The is FREE when requested on STANLEY NEUFELD contact with the outside world. glossary Associate Publisher letterhead. This means that, if you work for an OEM electronics company,

ZIFF-DAVIS PUBLISHING COMPANY representing a potential customer, you can get it. Good luck on obtaining Popular Electronics the booklet (address: Jericho Turnpike, Westbury, NY 11590). Editorial and Executive Offices One Park Avenue New York. New York 10016 I say "good luck" because most OEM distributors won't deal with 212- 725-3500 hobbyists. (I'm digressing here, but one thing always leads to another.) Hershel B. Sarbin, President Furman Hebb, Executive Vice President This view was succinctly summed up to me by Harold H. Powell, President Vincent Perry, Financial Vice President and Treasurer of Powell Electronics, Philadelphia, PA. He said his company uses video Phillip T. Heffernan, Senior Vice President, Marketing Edward D. Muhlfeld,SeniorVice President, Sports Division terminals to quote price and delivery on a real -time basis though inventory Philip Sine, Senior Vice President The is not to processing Frank Pomerantz, Vice President, Creative Services is spread throughout the country. system suited Arthur W. Butzow, Vice President, Production many small orders for one -time customers, he concluded. Lawrence Sporn, Vice President, Circulation George Morrissey, Vice President We surveyed 25 of the largest OEM distributors in the country (with 315 Sydney H. Rogers, Vice President stocking locations) on their policies regarding sales to nonindustrial Sidney Holtz, Vice President Al Traîna, Vice President accounts. Only three responded favorably: Almo Electronics Corp., Philip Korsant, Vice President Philadelphia, PA; Semiconductor Specialists, Chicago, IL; and Summit Paul H. Chook, Vice President. Market Planning Charles B. Seton, Secretary Distributors, Buffalo, NY. Some didn't reply. Edgar W. Hopper, Vice President, Electronics Div. How sad -for those who won't sell retail, and for us. I do believe that a William Ziff, Chairman -order (say, $15 minimum) counter would W. Bradford Briggs, Vice Chairman retail, cash -only, minimum -dollar be profitable for many of these distributors. A vacuum certainly exists in Midwestern Office The Pattis Group, 4761 West Touhy Ave., the walk -in electronic parts retail business; that is, local retailers with Lincolnwood, Illinois 60644, 312 679 -1100 broad parts inventories. With so many electronics hobbyists in the country GERALD E. WOLFE, THOMAS HOCKNEY Western Office (PE has close to 400,000), spending substantial money for devices that 9025 Wilshire Boulevard, Beverly Hills, CA 90211 include expensive MPU's, one would think that there is sufficient 213 273 -8050; BRadshaw 2 -1161 Western Advertising Manager. BUD DEAN motivation to serve them. Japan: James Yagi Oji Palace Aoyama; 6 -25, Minami Aoyama 6 Chome. Minato -Ku, Tokyo 407 -1930/6821, 582 -2851

Member Audit Bureau =,,,, of Circulations The publisher has no knowledge of any proprietary a,/ rights which will be violated by the making or using of any items disclosed in this issue.

4 POPULAR ELECTRONICS

www.americanradiohistory.com i Theworld'slargest catalog of electronic kits

Laboratory Breadboard Oscilloscopes Frequency Counters Digital Multimeters Amateur Radio Gear Color TV's Hi -Fi Components Radio Control Electronics Automotive, Fishing, Marine & Aircraft Accessories -over 400 kits in all!

Every Heathkit product comes with a fully -illustrated. HEATH - - step -by -step assembly manual I---- -, that tells you to Send to: Heath Company,- Dept. 10 -13 everything ycu need know to make kitbuilding fun and easy. Thousands Schlumberger Benton Harbor, Michigan 49022 people have of discovered the satisfaction - Yes. please rush my FREE Heathkit Catalog ! 1 and savings -of handcrafting a fine piece of 1 electronic equipment. You can build it better ' Name 1 ...let us show you how. Send for a free copy of the Heathkit ' Address Catalog today! ICity State Zip Heath Company. Dept. 10 -13 CL-579 Benton Harbor, Michigan 49022 fi=NMI= IM MN CIRCLE NO 5 ON FREE INFORMATION CARD JANUARY 1976 5

www.americanradiohistory.com understand why phasing should be of any procedure as before, this time maximizing practical consequence in consumer tape the combined output, while monitoring a recorders. Be assured that there is at least VTVM, TMM, or DMM connected between one application where phasing is impor- the junction of the two resistors and circuit tant: the dubbing of SO- or QS- encoded ground. records on tapes when the tape deck has As a final check, record a tone that Lr'/ separate record and playback heads. Im- sweeps from about 1000 to 15,000 Hz and proper phasing will "confuse" the matrix play it back while monitoring the decoder on playback. recorder's output. Improper phasing will

Letters I have devised a relatively simple way of produce serious peaks and dips within the adjusting the phasing between two tracks band, especially at the high end.D. when an oscilloscope isn't handy. First, Chan, La Salle, Quebec, Can. THE CASE FOR TAPE HEAD PHASING roughly align the heads as described in Mr. Hodges' column. Then combine the left In his reply to reader mail with reference and right channel outputs through two USING TACHOMETER ON CD IGNITION to his "Notes on Head Alignment" (August equal -value (say, 4700 -ohm) resistors. I would like to know if the tachometer 1975), Mr. Hodges stated that he does not Then fine adjust the heads using the same described in your June issue (Build a Digi- tal Marine/Auto Tachometer ") will work with either a conventional ignition or a CD system. -John Barnhart, New York, NY.

The type of ignition system has nothing NEW COMPACT to do with the operation of the tachometer, which is concerned only with the timing of the motor when it is running.

WORKING WITH MOS DEVICES ¡ c` The De ndìc r dable/Economy Sized CB Fromc Sweden IC The instructions for safe handling of 1021444 MOS devices ( "Senior Scientist Cal- culator," October 1975) don't seem quite fly right. Isn't it dangerous to ground yourself when working with electrical appliances? Shock can result from touching a point connected to the "hot" side of the ac line. Douglas Peters, Jersey City, NJ.

Yes, you're right. The third step on page 38 should read: "Ground yourself; wrap a length of wire mesh around your wrist, connect the free end of the mesh to a 1- megohm resistor, and terminate the free end of the resistor at a cold water pipe if metallic plumbing joints are used in the system, or to the grounding screw of an electrical outlet."

SCA DECODER I'm having some difficulty getting the SCA Decoder from "Experimenting with Phase -Locked Loops" (October, 1975) to work. I've doublechecked my wiring and it looks OK. Any ideas ? -Edward Fagan, Portsmouth, NH

But you need big, professional CB power geographic and climatic conditions. This First modify the circuit as follows: R13 ... and all the special, "no frills - no gim- means you get: 0.5% sensitivity; 5 Watt should be 100 ohms. Ground pin 1, and mick" features that only Handic offers. Output; 0.2/A1 Spurious Emission - that's Handic has the answer with two new, 3 250% better than FCC requirements. And, remove the connection between pins 7 and Ch. & 6 Ch. rigs that save time & money. Handic's unique .003% crystal frequency 8. If you have connected the input of the These compact, economy sized CB's tolerance, again exceeding our own FCC to the standard output jacks are small enough to fit in a sports car specs. Check the new Handic compacts SCA decoder dashboard - big enough to deliver the ... Model 305, 3 -Ch; Model 605, 6 -Ch. Dis- of your tuner, there might not be enough pro power you demand of a mobile or base cover the smart way to use CB. Ask your drive signal, due to the effects of de- station. Performance? It's Handic all the dealer. Remember Handic has its own way ... with advanced design electronics orange color, symbol of CB excellence. emphasis and SCA traps. If your tuner has a made to perform under Sweden's tough Ch -13 crystal supplied. "Composite Output" or FM Detector Out- put" jack, connect the decoder input to Send For FREE Catalog! that point. If you have an older tuner with- Handic CB radios include: mobile base transceivers: hand -held personal portable CB systems: scanners with out such a jack (multiplex output jacks FM radio option: antennas: microphones: selective call: and a full line of accessories. usually won't provide enough SCA signal), the 14340 N.W. 60th Ave.. Washington Bldg. tap some of the signal directly from Miami Lakes, Fla. 33014 (305) 558 -1522 THE DEPENDABLE CB FROM SWEDEN discriminator output. If this loads down the U s A I,,, In Canada: Scotomm Radio Inc.. Chomedey, Laval. Quebec circuit, use resistive coupling.

CIRCLE NO 22 ON FREE INFORMATIO CARO 6 POPULAR ELECTRONICS

www.americanradiohistory.com úM OHM@ M' 0 Iglir oao 0 on47pC CON P WITIE R It seems that a great many people that particular brand of computer. face cards are only S35.00 for serial came to the same conclusion that we SwTPC uses the standard Motorola or parallel types. did here at SwTPC. The M6800 is an MCM6830L7 ROM. This provides Memory expansion will be essen- outstanding processor and makes a automatic loading and an operating tial if you ever intend to use a resi- great computer "BUT" - Not all system that is compatable with other - dert assembler, or higher level lan- computers using the M6800 pro- systems using the standard widely guages such as APL or BASIC on cessor are the same. May we suggest sold Motorola evaluation set. As an your system. Assembler programs that you consider the following fea- owner of our 6800 computer system, typically require a minimum of 4,096 tures when you make your choice. you are eligible for membership in words of memory and higher level the Motorola Users Group. If you languages require even more. IT IS A COMPLETE join you have access to a library of 6800 SYSTEM? programs that will run on your sys- HOW DO YOU ENTER You cannot get all of the advan- tem. Editor and assembler programs AND READ DATA? tages of the 6800 system with only are available directly from SwTPC. Let's hope it is by way of a TTY, the processor chip. Unless the whole or video terminal. No one with a 6800 family of chips is used you can- CAN THE SYSTEM BE EXPANDED serious computer application would not possibly get all of the versitility AT A REASONABLE COST? consider attempting to enter data and superior performance that the Some of the limited systems be- from a switch and status light con - system is capable of providing. If for ing offered at lower prices can be solE. These may be educational, but instance the design does not use the expanded only with difficulty. Check they sure aren't practical. Calculator MC6820 parallel and the MC6850 the amount of memory that can be keypads and digital readouts are not serial integrated circuits for interfac- added and at what cost. How many much better. There is no substitute ing, you lose the programmable inter- additional interfaces can be added, if for a full alphanumeric keyboard and face feature that makes it so easy to any. How much of the above can be terminal system display for serious interconnect the computer system run off of the power supply provided wor k. with outside devices such as termi- with the system? The SwTPC 6800 is a registered trademark of nals, printers, disks, etc. can be expanded up to 16K words of Mikbug® Motorola Inc. memory in the standard cabinet and IS THE SOFTWARE with the power supply orovided. It COMPATABLE OR UNIQUE? may also be expanded up to eight If the design does not use the interface (I/0) boards for external Emon "Motorola" Mikbug® ROM, then the devices by simply plugging in the Computer System software and programs that will run cards. Memory is $125.00 for each with serial interface and 2,048 Words on the system are probably unique to 4,096 words of expansion and inter- of memory S450.00

Enclosed is S450 for my SwTPC Computer Kit Send Data

or BAC

or MC Ex Date

NAME

ADDRESS

CITY STATE ZIP

Southwest Technical Products Corp., Box 32040, San Antonio, Texas 78284

CIRCLE NO 53 ON FREE INFORMATION CARD JANUARY 1976 7

www.americanradiohistory.com Four different Only NRI gives schools give you you this 25" this 5" hobby- designed -for- DIAGONAL i TV... learning Color TV...

It's the only way you can (1) oscilloscope, CMOS digital get the feel of typical com- frequency counter, and an mercial circuitry, (2) learn integrated circuit color TV pat- bench techniques while build- tern generator. Where NRI ing complete units from the supplies a professional color ground" up, (3) perform over 35 "in -set" experiments during construction, and (4) No other home training end up with a 25" school gives you both an ex- diagonal solid -state clusive solid state color TV color TV with console and an SW' Quadra- cabinet and a 4 -chan- phonic Receiver complete nel quadraphonic with four speakers ... all in Audio Center. one course. You get both for less than the tuition cost of NRI passes the TV or Audio alone from the savings on to you next leading school. And NRI can save you money pattern generator, most only NRI's Master Course in because our engineering other schools use a TV Color TV /Audio servicing eliminates the cost of buying set with a built in align- lets you train on equipment from an outside source. We ment generator of no use for designed specifically for train- pay no salesman's commis- servicing other sets. Only NRI ing with exclusive "power -on" sion. Students are enrolled designs, engineers, and sup- features. by mail only. The savings are plies training kits specifically for NRI doesn't give you hobby passed on to you in the form learning and professional use. kits or commercial sub- assem- of low tuition fees, extras like You can pay hundreds of dol- blies. We invested the time the TV's console cabinet and lars more for a similar course and money to design equip- the four speaker Quad Sys- and not get a nickel's worth ment with learning in mind. tem; a 5" triggered sweep more in training and equipment.

Trademark of CBS, Inc.

8 POPULAR ELECTRONICS

www.americanradiohistory.com ...plus complete Quadraphonic Audio Center!

More know -how per dollar programs oriented to full Or you can study other -time needs. opportunity fields like Digital That's what it all boils down or part career to, the quality of training you Choice of Courses Computer Electronics, Citi- Widest Radio, Commu- get for the money you spend. zens Band with CB, Digital nications, In our 62 -year history, more Computer, and Aircraft or than a million students have other career Marine Elec- come to NRI and we're fully opportunities tronics, approved for career study Ra- under the G.I. Bill. We must Mobile be teaching something right. dio, and more. Send Some of those "right" things for our free cata- are bite -size lessons to ease log and see for yourself understanding and speed that no one gives you learning . . . personal grading NRI offers not one, but five more training and equip - of all tests, with comments excellent TV /Audio servicing ment for your dollar. There's or explanations where needed courses so you can tailor io obligation, and no sales- ... a full -time staff of engi- your training to your budget. man will call. neer /instructors to help if If card is missing, write to: you need it ... plenty of kits and experiments to give you hands -on training and fully NRI SCHOOLS ... McGraw -Hill Continuing professional NRI Education Center ( 3939 Wisconsin Avenue Washington, D.C. 20016

1,r1 l

JANUARY 1976 11

www.americanradiohistory.com L400 weighs 16 lb (7.3 kg), measures 17 -3/4" SURVEYOR PROGRAMMABLE SCANNER H x 10" W x 81/2" D (45.1 x 25.4 x 21.6 cm). The new Model 10 -P Programmable Scan- Cabinet finish is natural walnut, and the ner from Surveyor Manufacturing is a speaker grille (removable) is black double solid- state, dual- conversion receiver that knit. $90.00. covers the vhf HI, LO or uhf bands. A prior- CIRCLE NO. 86 ON FREE INFORMATION CARD ity switch is also featured. This allows the

search of Channel 1 every 1.75 seconds.

JERROLD TV SIGNAL INDICATOR Channel 1 will lock in its signal even New Products though another channel is being received. The Jerrold "Levelite" checks signal levels Additional information on new products at a TV set's antenna or MATV input termi- Has squelch, volume, and manual /auto- covered in this section is available from matic scan controls, as well as built -in tele- the manufacturers. Either nals and provides a go -no go visual indica- circle the item's scoping whip antennas. $189.00 code number on the Reader Service Card tion (LED) of the presence of a signal. The inside the back cover or write to the man- CIRCLE NO. 91 ON FREE INFORMATION CARD ufacturer at the address given.

CONTINENTAL SPECIALTIES BREADBOARDING KIT

The new Proto -Board 6 by Continental UNIVERSAL LOGIC FAMILY PULSER ,Specialties offers 630 component tie Kurz-Kasch announces its new Model points and 6 14 -pin DIP IC capacity. The kit HL -583 in- circuit simulator or logic -state includes one QT -47S breadboarding sock- pulser for use with RTL, HTL, DTL, TTL, and et, two QT-47B bus strips, four 5 -way bind- CMOS. It delivers a HIGH -level pulse ex- ing posts, a metal ground and base plate, ceeding the value required by these rubber feet, and hardware. All connections families to yield a logic one, and a between components can be made with Low -level pulse below the value required to brightness of the LED also gives some in- #22 hookup wire. Measures 6" W x 4" D yield a logic zero. Selection of one -shot or dication of signal strength. It can be set for (15.24 x 10.2 cm). $15.95 continuous operation is made by a slide either distant or local signals. Battery- CIRCLE NO. 92 ON FREE INFORMATION CARD switch on the probe barrel. $96.00 operated, it is hand -held and has adapters CIRCLE NO. 84 ON FREE INFORMATION CARD for connection to various types of termi- AMTRONCRAFT STEREO AMPLIFIER KIT nals. $47.50 Amtroncraft announces its new Model UK MARANTZ AM /FM STEREO TUNER CIRCLE NO. 81 ON FREE INFORMATION CARD 192 stereo power amplifier in kit form. Its Marantz's new Model 150 AM /FM stereo rated output power is 50 W rms/channel at tuner has a built -in 3" (7.6 -cm) oscillo- CUSHCRAFT BASE ANTENNA 1% THD. Claimed frequency response is Dolby noise scope, reduction circuitry, and The Model CX -1000 by Cushcraft is an om- within 2 dB from 10 to 10,000 Hz. Input a phase -locked -loop multiplex detector. It nidirectional base station antenna using a also boasts an 18 -pole linear-phase i -f filter coaxial stub matching system. The manufacturer states that heavy -gauge aluminum tubing is used along with stainless steel fasteners. Accepts any mast up to 13/4" (3.5 cm), and is designed for use with 52 -ohm coax.

CIRCLE NO. 88 ON FREE INFORMATION CARD

E.F. JOHNSON CB RADIOTELEPHONE

The Messenger 130A is a new version of and flywheel tuning. Switching functions E.F. Johnson's radiotelephone handset CB sensitivity is 1 V for full power output. Input include STEREO ONLY, HI BLEND, MUTING, mobile transceiver. Features new noise and output impedances are rated at 1000 and MONO. The scope can be used for l- suppression circuitry, a molded speaker and 4 ohms respectively. Requires a 55-V and 4- channel audio balancing, tuning, grille and integrated mounting fins. Can be dc power supply, such as the company's and multipath adjustments. $599.95. used with positive or negative ground UK 665. $139.95 CIRCLE NO. 93 ON FREE INFORMATION CARD CIRCLE NO. 85 ON FREE INFORMATION CARD

ADJUSTABLE CALCULATOR STAND ADS TWO -WAY LOUDSPEAKER SYSTEM Analog & Digital Systems announces its The CalCradle Executive, by one -up, inc., is new Model L400 bookshelf speaker sys- a calculator stand that tilts and pivots to the tem, a two -driver, two -way acoustic - angle required for glare -free viewing and suspension unit. A long -throw 7 -inch easy keyboard operation of a pocket cal- woofer, with a resonant frequency of 30 Hz, culator. Accepts both horizontal and verti- operates over a range of 30 to 1500 Hz. A cal models, and completely disassembles 1 -inch soft -dome tweeter is suspended in a for storage. The CalCradle Executive is sealed acoustic chamber with a special made of clear acrylic and chrome. $12.98. damping fluid. The tweeter covers the Address: one -up, inc., 1303 Avocado, Suite 1500 -20,000 Hz range, and is said to have 235, Newport Ctr, Newport Beach, CA flat response, wide dispersion, and good sources, and has the option of private lis- 92660. transient response. Air -core inductors and tening with automatic speaker silencing metal -film capacitors are used in the when the handset is lifted. The transceiver SHAKESPEARE STATION MONITOR cross -over network. Impedance is 5 ohms covers 23 channels and has PA minimum. An 85 -dB SPL is produced with 2 capabilities. $199.95 Shakespeare's new base station monitor, watts rms input at a distance of 10 ft. The CIRCLE NO. 89 ON FREE INFORMATION CARO "The Defender," measures r -f power out - 12 POPULAR ELECTRONICS

www.americanradiohistory.com 5 WAYS TO STOP WASTING TIME IN ELECTRONICS. iStop wasting your time soldering. Save popular solderless breadboarding system hours of soldering, desoldering, re- ...our Proto -Eoard " line. For just $15.95* soldering with QT sockets and bus you can have our PB -6 Proto -Board kit. strips. Connect and disconnect Takes about 10 minutes to assemble, resistors, capacitors, transistors, IC's etc., and gives you 630 literally as fast as you can push in solderless QT -or pull out -a lead. Make terminals. On the other instant interconnections end of the spectrum with short lengths of wire. is our giant PB -134, And interlock sockets with 3,060 and bus strips for solderless infinite expand- terminals ability on bench, for $79.95 chassis, plug -in cards, or only 2.61$ apiece! You can etc. At $2.00 -12.50* you'll choose from a variety of models, wonder how you've done with or without regulated power without them! supplies. Stop wasting Stop wasting your your time design- time testing. ing circuits. Design You can own the test gear you MateTM 1 will help, by need at economical providing you with QT hookup versa- prices. Our Design Mate 2, for instance, tility (see above), a continuously -variable gives you a 3- waveform function 5 -15V, 600mA 1 %- regulated supply, and a generator - voltmeter to monitor supply or circuit. Plug sine, square and triangle -from it in, turn it on and 1 Hz to 100 kHz ... for just start designing more $ 64.95 by soldering less. At Design Mate 3 $49.95 you can R/C bridge pro- afford to. vides 5 %- Stop wasting accurate your time testing. measurements On DIP IC's, of unknown resistors finding the lead and capacitors from 10 is111411111 you want -and making sure you don't short to 100 meg and 10 pF to 1 uF, with others -can be as delicate as built -in LED null i ldication. Price is a "micro" surgery. Until you discover $54.95* And as you're reading this, we're our handy Proto- CIipTM busy adding new low- priced, high - ...the instant, short - quality Design Mates. proof way to test IC's Stop wasting your time reading. Send for up to 24 pins. the complete CSC catalog and dis- Available without cable or tributor list... and start making more with cable, they're of the most yourtime in electronics. economical and foolproof IC *Manufacturers recommended retail. test aids on the market. CONTINENTAL SPECIALTIES CORPORATION Stop wasting your time breadboarding. Small budgets or big requirements are no obstacle to 44 Kendall Street, Box 1942 New Haven.=0= owning and enjoying today's most CT 06509.203- 624 -3103 TWX 710- 465 -1227 West Coast office Box 7809, San Francisco, CA 4 94119 .415- 421 -3872 TWX 910 -372 -7992 c 1975 Continental Specialties Corp Canada Ler Finkler Ltd . Ontario CIRCLE NO 14 ON FREE INFORMATION CARD

JANUARY 1976 13

www.americanradiohistory.com WEN SOLDERING GUN KIT TECHNICS DIRECT-DRIVE RECORD CHANGER Wen Products' Model 222K5 Soldering Technics by Panasonic announces its new Gun Kit includes a single -post soldering Model SL -1350 direct -drive record gun (Model 222), a fine (25 -100 W) and a changer /turntable. The changer will regular (100 -200 W) tip, and a flat -iron at- handle a stack of six records, and can be tachment which seals plastic bags put immediately into the shut -off mode drymounts photos, and aids in furniture without having to play through the stack. repair. Also includes a plastic cutting at- Manual operation is also possible. The put, SWR, and percent modulation when tachment for cutting plastic sheets, burn- SL -1350 features a gimbal- suspended, inserted in the coax line between trans- ing wood and leather designs, and working low-friction, modified -S type tonearm for ceiver and antenna. Pushbutton switches with plastic or asphalt tile. The soldering select the meter function. Also built -in is an gun features Automatic Thermal Regula- antenna matcher to convert reactive loads tion, which is said to minimize idle current to 50 -ohm resistive ones. A switch controls through the tip, but provides full heat flow the matcher in /out function. $99.95 when needed.

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TIMEPIECE WITH PRECISION stereo and CD -4 cartridges. The tonearm has two -way damped cueing, antiskating ONLY $109.95 adjustment, and counterweight arm ACCURACY...FOR balancing and tracking force adjustments. An aluminum die -cast platter weighs 3.9 lb Parrott Precision Electronics proudly presents the Condor and (1.8 kg), and has raised dots along its outer edge for stroboscopic checks. A the Squire. The face of these fine watches appears completely speed black until you're ready to use it. Just touch the tiny built -in flasher is used for these adjustments, which can be made at 331/3 and 45 button at the 2 o'clock position and the time, in hours, CONR rpm, at line frequencies of either 50 or 60 minutes and seconds, will be clearly displayed in bright numerals. Hz. A hinged dust cover is included. A touch of the button at $349.95 the 8 o'clock position CIRCLE NO. 96 ON FREE INFORMATION CARD will illuminate

today's date. -ii LEADER HAM OSCILLOSCOPE Compare These Leader Instruments' new Model Features With LBO- 310Ham oscilloscope monitors Watches Costing Twice As Much: waveforms in the receiver i -f section as well

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resistant. . . these luxurious watches come with complete in- Time Setting. struction booklets and a full TWO -YEAR GUARANTEE from date BATTERY SAVER of purchase. circuit. The new Condor and Squire digital electronic watches can be purchased only through the mail with the coupon below or by calling 615- 528 -6502 between 10 a.m. and 11 p.m. EST. Telephone orders will be accepted only if MASTER CHARGE or BANK AMERICARD are used. The first 1,000 telephone customers will receive their order for $95.00. No COD orders please. Residents of Tennessee must add a 5 percent sales tax.

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I Total enclosed $ Name as SSB, AM, and RTTY outputs. The 3 -inch Address (7.6 -cm) scope has a vertical sensitivity of City State Zip 20 mV /division and a bandwidth of dc to 4 MHz. Proper RTTY and SSB tuning may be Condor: number ordered- Yellow Gold ( I White Rhodium Squire: number ordered- Yellow Gold () White Rhodium made with the help of a built-in two -tone generator. With the LA-31 adapter ($22.95), the scope provides continuous monitoring Suite 6, 440 North Washington Ave., of r -f output to 500 W over a frequency arrott Cookeville, Tennessee 38501. range of 1.8 to 54MHz with vertical sensitiv- 'Itf;('ISUoN ELEC'l'lülNll'5 ity of 1 W /division into 50- or 75 -ohm impedances. $269.95.

CIRCLE NO. 97 ON FREE INFORMATION CARD

CIRCLE NO 60 ON FREE INFORMATION CARD 14 POPULAR ELECTRONICS

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The quarterback is picking just the right spot to call a screen pass. He passes. The running back carries the ball to a touchdown. Victory!

Pick yourself the right CB radio. No problems to tackle when you own a PACE CB radio. They're designed to carry your conversations with clarity and high performance. The quarterback gets total support from his team on the field. In the same manner will you get total Pace support in the field. From our experienced service centers coast to coast. From our retailers and distributors. Grant yourself that victorious feeling and pass along, "I own a PACE CB."

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((o)) PATHCOM INC. PACE TWO -WAY RADIO PRODUCTS 02102 24049 S. Frampton Ave., Hart or City, CA. 90710 Available in Canada from Superior Electronics Inc. Export (all other parts of the world): 2200 Shames Jr. Westbury, N Y 11590.

CIRCLE NO 41 ON FREE INFORMATION CARO JANUARY 1976 15

www.americanradiohistory.com NOW there's a quick easy way for you New Literature

SIMPSON TEST EQUIPMENT CATALOG A 60 -page catalog (No. 4400) from Simpson Electric Co. describes their line of analog, digital, and AnaLed panel meters, chart recorders, meter relays, pyrometers, control- lers, test equipment and a variety of portable instrumentation. It is illustrated with to learn ... review ... improve your photographs, line drawings, and charts of Electronics fundamentals. which provide information such as ranges, understanding calibration, dimensions and weights. In- That's right. A new "audio visual" learning experience in basic Electronics cluded are prices for all models and acces- and Electricity. Quick. Easy. And it's fun, too. sories. Address: Simpson Electric Co., 853 Four pre- recorded cassette tapes take you right into a classroom in Dundee Ave., Elgin, IL 60120. Electronics. Eleven class sessions in all ... it's just like you are there! You'll listen to a instructor his CIE and students explore AC /DC, transistors, circuits, SHURE HIGH -FIDELITY CATALOG cells, batteries, IC's, electronic symbols and other meaningful subjects. As you listen, you'll follow along through six instruction manuals that The latest high -fidelity catalog (AL210 -P) contain over 150 easy -to- understand illustrations, photos, and diagrams. Sit from Shure Brothers includes a selection back, relax, and learn. guide to replacement styli for nearly all car-

Nearly 3 hours of recorded, programmed instruction . . . designed and tridges it has manufactured in the past 15 developed to help you grasp the all- important basic theories and applications of years. Includes trackability, stylus confi- Electronics and Electricity. guration, and tracking forces. Also high- Order your exciting Audio Visual "Class in Electronics" TODAY and qualify lights two tonearms, a stereo preamplifier, for this special Bonus Offer. headphone amplifier, and stylus force gauge. Address: Shure Brothers Inc. 222 receive a to the Order now and one -year FREE subscription Hartrey Ave. Evanston, IL 60204. BONUS bi- monthly CIE Electron newspaper. Packed with timely, OFFER thought -provoking electronics articles - new developments - service tips - job opportunities. Free with each AUTO RADIO INTERFERENCE REPORT order. A report detailing a technique for reducing You must be completely satisfied or return the material within automobile ignition interference is now 10 days for a complete - no questions asked - refund. available. A team at Stanford Research Center was able to reduce radio noise from RUSH me your no -risk Audio Visual program that combines sight a 1972 American car by a factor of from 5 to and sound in a new, exciting learning experience and put me down 10 (varying with frequency) over a range of for a FREE one -year subscription to the CIE Electron. 20 to 1000 MHz. A few low-cost electrical must Check One, please components be added, which according to tests have no undesirable effects on 4 cassette n#01 -122. Set includes instruction manuals, recorded the car's operation or level of exhaust tapes, binder /file. $24.95 (Ohio Res. add 51/2% Sales Tax) emissions. A copy of the report, Accession -124. Set includes Cassette Tape Recorder, 4 recorded cas- No. PB 239 -471 is available for $6.25. Ad- pi#01 AC adapter, settes, remote -control mike and stand, earphone, dress: National Technical Information Ser- power cord, batteries, 6 instruction manuals, binder /file. vice, Springfield, VA 22161. $49.90 (Ohio Res. add 51/2% Sales Tax) is my .. Enclosed THYRISTOR GATE NOISE Check Money Order (BC- 20 -75) The latest in the Westinghouse semiconductor Tech Tips series covers noise dis- Print Name Age crimination in thyristor firing circuits. Noise Discrimination For Your Firing Cir- Address Apt cuit," Tech Tip 4 -4, discusses the effects of false triggering caused by energization or City de- energization of reactive loads in the vi- cinity of thyristors. The article provides typ- State Zip ical circuit diagrams, design charts, and equations to help the designer develop CIE BOO tilli'l' noise -discrimination circuitry to suppress 1776 E. 17th Street Cleveland. Ohio 44114 gate -lead transients. Address: Semicon- lidurutn,nul Er2t rit,turn, nt ra lut,, by mad ductor Division, Westinghouse Electric Corp., Youngwood, PA 15697

16 CIRCLE NO I1 ON FREE INFORMATION CARD POPULAR ELECTRONICS

www.americanradiohistory.com For the $400 -class CB customer Realistic has what's really new and 4000 places to find it.

Reading time 48 seconds: Not everyone has four C -notes to lay out for hobby or business equipment. But on the other hand, the new Realistic Navaho TRC-57 actually costs no more than a basic 35mm SLR camera. And for 399.95* you get an AM /SSB base/mobile transceiver with everything you'd expect - plus a lot you wouldn't. + Digital phase -locked synthesizer and crystal lattice filter for unusual selectivity. + Automatic modulation gain control for full power always, whether you talk loud or soft. + ANL and blanker for chopping out noise. + LED -indicator AM /USB /LSB mode lights. + Separate SWR and S /RF power meters that turn red on transmit. + Precise LED -readout clock switchable fo- 12 or 24 -hour time. And of course it's FCC Type Accepted and UL listed. The new Navaho. You get something more by accepting nothing less!

'Retail price may vary at individual stores and dealers.

ACK SOLD ONLY WHERE YOU SEE THIS SIGN: FREE, CATALOG 164 PAGES OVER 2000 ITEMS Get your copy today at our nearest store or dealer. Or write: 642 Radio Shack A TANDY CORPORATION COMPANY P.O. Box 1052 Fort Worth, Texas 76101 (Please Print) Just Say Name Apt. "Charge It" at participating Street stores

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JANUARY 1976 CIRCLE NO 41 ON FREE INFORMATION CARD 17

www.americanradiohistory.com ing the level until the sounds from the two drivers blend and seem to come from a point midway between the two. Next, follow the same procedure with the tweeter level control, increasing it until the tweeter's output blends Stereo Scene with that of the other two, and does not appear to be coming from a separate point source. Snyder suggests adjusting the speaker in place to com- By Art Salsberg pensate for reflections, keeping your (Ralph Hodges returns next month.) head down close to the enclosure. AUDIO POTPOURRI This method doesn't require test instruments, and equally important, it

HERE ARE some kernels of audio 1 reveals loops and nodes beginning saves a lot of energy expended by information, ranging in variety to appear at the periphery of an 8 -inch jumping up and down to "hear" the from adjusting speaker- system level (20.3 -cm) cone driven at 2000 Hz. system with a new setting! controls to the different hearing per- When the input signal is raised to 9000 ceptions of left- handed and right - Hz, as pictured in Fig. 2, the entire New Audio Power Ruling. The FTC handed people. surface is covered with loops and has a new interpretation of its "Rule nodes, and little sound is radiated. on Audio Power Disclosure." The Loudspeaker Behavior. Loud- agency has backed off from its origi- speakers and drivers were once de- Setting Speaker Level Controls. nal requirement that amplifiers be op- signed by intuition and practical ex- Literature from Speakerlab of Seattle, erated at 1/3 rated power for one hour perience. The empirical approach is WA, sets down an interesting method before testing. This is not the way disappearing, however. With the of adjusting speaker level controls - amplifiers are used in the home, where growing use of mathematical models, you know, those tweeter and mid- musical passages require peak power cone geometry and material can be range level controls usually on the for only short periods of time, and the chosen to obtain a specific frequency rear of the enclosure. According to au- average power seldom reaches the 1/3 response. thor Pay Snyder, the center settings of conditioning level. So, fuses popped, Phillips Research Labs (in the these controls do not necessarily pro- relays opened, or output transistors Netherlands), for example, uses a vide flat response, due to production overheated during the pre -test condi- computer program to solve driver be- variations in speaker sensitivities. tioning, especially in high -power havior problems, such as determining (Room acoustics can play a part, too!) amplifiers. frequency characteristics of the He suggests setting amplifier tone If the ruling was maintained, many sound wavefront and radiated power controls to "flat" and the balance con- manufacturers faced the choice of de- as a function of cone material. trol so that only one speaker is play- rating their products' power outputs, Theoretical results are verified by ing. Listen to a familiar piece of music or improving thermal transfer through viewing driver motion holographical- with the level controls at minimum, extra heat sinking or forced -air cool- ly. Typical results are shown in Figs. 1 which should leave you with sound ing. The former would place some and 2. At low frequencies, the cone coming only from the woofer. Slowly manufacturers at a competitive disad- vibrates as a rigid surface. But above a turn up the midrange control until you vantage, while the latter course would certain point, standing waves begin to hear sound coming from this driver as have substantially increased costs. appear on the cone. For example, Fig. well as the woofer. Continue increas- Bedeviled by this requirement, nearly two -dozen manufacturers requested a reinterpretation of the conditioning procedure, supporting their contentions with test data. In response, the FTC approved automatic recycling, allowing equipment to cut off or go on automatically until a total of one hour of "on" time is accumu- lated. Furthermore, if thermal buildup is a problem, tests may commence at low output power to permit cooling.

Live Recording. If you've ever struggled with miking live perform- ances (and haven't we all!), you'll appreciate the tips offered by Shure Bros., 222 Hartrey Ave., Evanston, IL 60204, in its free brochure #AL 493. It describes in nontechnical terms how to mike voices and instruments, in- Figs. 1. (left) and 2. Holographs of motion in drivers.

18 POPULAR ELECTRONICS

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Bass Belles HOW TO MIX AND MATCH YOUR HI-FI/COMPONENTS ulld GRACE BUMBRY ENRICO CARUSOi EARL HINES HI-FI Speakers '-ECTRONIC Elect IGUAL onic Projects For Year Car RISTMATCH iasy Costcbvction Lamp- Readout 50% .ow Cost VU Indicator of f Microphones on your choice of these for CE'srs & Hams Test Reports: O lkyn Tx -555 %carvel outstanding publications ER Nlc,otower II Speaker Inlenöalbnal 1C-500 Here's a great offer for readers from you may select as many as the publishers of Psychology Today, four at our special introduc- Skiing, Popular Photography and all tory rates -up to 50% off. the other outstanding publications shown' on this page. So why hesitate? Select the publications you wish to re- Select any of the publications you ceive -and save from 99¢ to see here -and subscribe to them at $6.00 on your selections. discount rates of up to 50% off. To enter your subscriptions, simply Whether your particular thing is ski- check off the publications you want on ing, boating or photography ... elec- the postpaid card, detach it and mail. If tronics, flying, cycling or cars . . . the card is missing, order your sub- stereos, news, psychology or sports .. scriptions by writing to Magazines At we're sure you'll spot a magazine here Discount, á division of Ziff -Davis that can meet your special interest. No Publishing Company, P.O. Box 2779, need to stop with just one, either, since Boulder, Colorado 80302.

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www.americanradiohistory.com cluding piano, and specifies the types Thus, two mikes are needed with a money" economy. Pictured here are a of mikes best suited for certain in- grand piano, and one of the secrets few new initiates to this elite club. struments. For example, the brochure divulged here is that the mikes must They are: Infinity Systems' Servo - states that a mike with a rising re- he out of phase with each other. Statik 1A speaker system, which con- sponse gives maximum brightness sists of two electrostatic screens, and when used near strings; one with a The Luxury Class. Along with Rolls a "base cube" containing an 18 -inch great proximity effect gives best low - Royce convertibles and platinum (45.6 -cm) woofer with its own 150 -W frequency response when positioned jewelry, there is a category of audio dc servo amplifier. Only $4000. Note at the resonant underside of a piano. equipment that simply ignores a "tight that separate stereo amplifiers for the mid -range (100 to 250 W) and tweeter (35 to 125 W) sections must be added. Then there's the Gale GT2101 optical servo turntable, with modernistic plexiglass and stainless -steel design. Speed is monitored on a three -digit LED display, referenced to a quartz crystal oscillator. Only $1,875 (less tone arm and cartridge, of course). Another entry is the Luxman M -6000 stereo power amplifier, rated at 300 W /channel into 8 ohms, both channels driven, with no more than 0.05% THD and IM, from 20 to 20,000 Hz. It features sophisticated thermal- and current -activated protection networks, with a 5- second (nominal) Infinity Systems stabilization period monitored by a Servo -Statik IA has two electrostatic screens LED before speaker outputs are ac- and separate 18 -inch tivated. Price is $2,995, or about $26 woofer with amplifier. per pound. Are You Left Eared or Right Eared? According to an article in Scientific American, October 1975, right- and left- handed people perceive auditory illusions in different ways. In a computer -controlled experiment, reactions were monitored to a sequence of tones whose amplitudes, frequencies, and durations were precisely regulated. Tonal sequences were presented to the subjects through headphones so that when one ear received a high (800 -Hz) tone, Gale GT2101 optical the other received a low (400 -Hz) tone. servo turntable is made Right- handed subjects tended to of plexiglass and localize the high tones in the right ear, stainless steel with alternately hearing the low tones in LED speed readout. the left ear. Oddly enough, the results AsePf were the same when the headphones Litman M-6000 stereo were reversed. Lefties, interestingly, power amplifier were just as likely to localize the high provides .300 watts tone in the left ear as in the right, ac- per channel into 8 ohms cording to the report. both channels driven. The Next Sound You Hear... In the past, the program material you listened to often dictated the quality of audio equipment you purchased. It was commonplace for audio salesmen to divide their customers into two groups -those who listened to classical music and those who didn't. The former were led to higher -quality components, while jazz, pop, and rock

22 POPULAR ELECTRONICS

www.americanradiohistory.com You make a tape with time and thought. Carefully chosen selections recorded in the sequence that most pleases you. The musical coherence and percep- tion is yours a personal expression. An when the time is right to share That experience with someone you care for, having to stop and turn the tape over can break the mood you worked to create. Interruptions like that don't happen with the A -4300. You can enoycontin- uous music on both sides of a tape with the automatic reverse function. And with automatic repeat, a favorite tape will play as long as you like., Whether ou want he music up ront or ini the background, ('heck out the A- 431313, and listen to it for as the A -4300 can lung as you like. Just call 1800) 447- 4700' w far the name of your nearest TEAL retailer. give In Illinois, call M004322-4400.ur you solid TEAC. music for The (orp Ovation has been. TEAC Curpnatiun of Anuriru 7733 Telegraph Road the 901140 better Montela.1111, l'a. part of an ® : TEA(' 107 evening,- when you don't want the music to stop TEAL A -4300 JANUARY 1976 23

www.americanradiohistory.com Youkl never

Bsuspectob O leads a double life

our course teaches skills By day, that qualify you to seek out he's a 9 -to -5 man. an electronics job, advance in By night, the one you may already an explorer in a field hold, or further your education that really interests him! in electronics. An independently conducted There was something different survey shows that most of our about Bob Gordon. Something graduates feel they have gained you couldn't quite put your one or more career advancement finger on. He was good at his benefits from the course. (Survey job. And he took pains to do it results are available upon well. But on certain evenings, at request.) the stroke of 5, he'd be the first one out the door and on the bus. And that can be How you gain so much The way he'd rush, people your starting point, too. would often ask, "Doing some- from Bell & Howell Schools' thing special again tonight ?" Right now, you stand where home -learning program... Bob stood when he first "Sure am!" he'd laugh. And Gordon How can you pick up skills off he'd go. started out. It's up to you to the ability and enthu- without quitting your job What his pals were never told provide or traveling to night school? was that after dinner Bob would siasm. Bell & Howell Schools, a leader in electronics education, You certainly won't do head for his basement. There, it just by reading a stack of on a simple old wooden table, will provide the opportunity to learn and grow in textbooks. That's not the sort was something very different -right of thing that would make Bob from Bob Gordon's 9 -to -5 routine. your home! home from Bob is already on the verge Gordon (or you) rush It was a challenge. A challenge work-not by a long shot! that seemed to change him into of having real skills in electronics. know it, You need actual electronic another person. Now, at last, he And, almost before you equipment to work and learn could work with his own two you can be there, too. with. And that's what you'll hands -roll up his sleeves, to have. Of course, we'll start you probe, experiment, and learn. Learning electronics off with the basic principles. Assemble advanced electronic at home -what's in it for you? You'll build and test simple equipment, including a 25 "- When you take Bell & Howell circuits with the Lab Starter Kit diagonal color TV with digital Schools' at -home learning course we'll send you. features! And all the while in Home Entertainment Elec- Then you'll move up to the gaining important new occu- tronic Systems, you develop a Electro -Labe Electronics Training pational skills. lot of important skills. First, System. Piece by piece, you'll you'll gather the know -how to actually build a design console How he started... troubleshoot and service most and put together circuits without Not long ago, Bob Gordon models of hi -fi amps, intercoms, soldering. You'll construct a filled out and mailed a card much automobile receivers, PA systems, digital multimeter to measure like the one attached to this and AM /FM tuners. voltage, current, and resistance. page. At the time, he had almost By the end of the program, You'll assemble a solid -state no experience in electronics. But you'll know how to service most "triggered- sweep" oscilloscope to he did have two important models of color and black -and- monitor and analyze IC circuitry. qualifications: desire and ambi- white TV's. When components for the TV tion. Plus a knack with tools and While no school can guarantee arrive, you'll already be com- an urge to put them to work. a job or income opportunity -- fortable with electronic concepts 24 POPULAR ELECTRONICS

www.americanradiohistory.com and equipment. And once you assemble that 25 "- diagonal color TV, you'll understand the technology behind no- warm -up tuning, automatic channel selection, on- screen time and channel digits, plus a great deal more! Home learning with a personal touch. At Bell & Howell Schools, we try not to keep a student waiting. Should a question come up, we invite you to use our tollfree phone -in service. Talk to one of our instructors -he'll either have your answer or know where to get it in a hurry. Face -to -face "Help Sessions" are another useful service of the Home Entertainment Electronics course. They are held in fifty cities throughout the U.S. at various times of the year. You can discuss electronics in person with trained instructors, talk of your experiences and ambitions with fellow students. These extras are part of a care fully planned program developed by Bell & Howell Schools. Experience with thousands of at -home learners has _ efined our teaching methods -and is helping make the path to a Technician Certificate a little easier. A Certificate currently being pursued by over 100,000 students! Mail the postpaid card today for all the facts - decide after you get them! We invite you to fill out and mail the attached card now, while it's within reach. It asks no commitment on your part- just offers full details on how to learn electronics at home and enjoy it. Who knows? You may soon be leading a double life like Bob Gordon. And when friends ask, "Can you really service TV's ? " -you'll answer with a grin. "I not only know how to service them, I know how to build them!" Note: When taken for vocational purposes, this program is approved by the state approval agency for Veterans' Benefits.

If card has been used, write to: An Electronics Home Study School DVFRV If1STITIJTE OFTECHnOLOGY

ONE OF THE BELL s HOWELL SCHOOLS mutated TV test pattern "Electro-Labs" is a registered trademark of the Bell & Howell Company. 4141 Belmont, Chicago, Wmois 60641

JANUARY 1976 27

www.americanradiohistory.com a listeners were often told that top- Do your stereo system favor- notch equipment wasn't really needed for their uses. Those days are gone! Today's listeners to nonclassical music now need high -quality audio gear just as UPGRADE! much as those who prefer orchestral and chamber music. This is especially true of progressive -jazz Convert your System from -rock and Ceramic to Magnetic Car- fans. Electronic instruments, such as tridge with Pickering's synthesizers, have wrought this new preamplifier. change. So have the more complex You'll appreciate this drum techniques that have evolved, easy, low cost method for which make strong use of cymbals to getting so much more out create a continual music line. of your stereo system. Use Representative of what one can exit to help get real hi fi from pect from jazz and rock releases in the your system. not -too -distant future is the use of a new instrument, the Syntar, manufac- SPECIFICATIONS FOR THE PP -1 PREAMPLIFIER AUDIOPHILE NET tured by Electronic Music Labs, Ver- Input Impedance: 47,000 ohms Signal to Noise Ratio: 60 dB Min. non, CT. It's a marriage of the full -

Gain (q 1 kHz: 38 dB Crosstalk: Better than 60 dB blown synthesizer and the electric Frequency Response RIAA Rumble Filter: Attenuates rumble guitar. A fiberglass -body Armstrong 30 -15000 Hz: *-2 dB frequencies a minimum of 15 dB guitar is used, with each string controlling a separately programmable STEREO CONVERSION KIT (PP1 /V15 AT -2) consists of the Pre - synthesizer. Therefore, a guitarist can Amplifier and Pickering's V -15 AT-2 cartridge (which is listed at $24.95). Total Value $54.90 for only $39.95. simulate traditional instrument voices of wind and percussion, as well as special sound effects. Further, PICKERING For further information write Pickering & Co.. Inc. through the appropriate use of en- Dept.PE,101 Sunnyside Blvd.. Plainview. N.Y. 11803 "for those who can hear the difference velope generators and filters, such CIRCLE NO. 43 ON FREE INFORMATION CARD guitar feats as infinite sustain, poly- tonal slides, and deriving full chords from a single plucked note will now be made possible.

SAVE ()N I listened to a demonstration cas- LISTEN! sette tape, and there's no doubt that a Brand Name Audio top -quality audio system would be re- We're one of music the country's Components quired to appreciate the type of largest Mail the instrument can generate. Two of Order Houses the finer guitarists around, John of Stereo Write Today for Our McLaughlin of the Mahavishnu Or- FREE Audio Equipment Catalog chestra, and Steve Howe of the Yes, DIXIE is one of the oldest and largest audio compo- and Musical nent mail order houses in the country. Our prices on are said to be currently mastering the Instruments. brand name components are actually LOWER than "Discounter ". See our new catalog or call us for a Syntar. (Sorry, the tape isn't available.) price quote. Everything shipped factory -sealed with Our volume buying power enables full manufacturer's we ranty. us to pass the savings on to you. And Next- Input jacks on the back of i ROSS Listen to us ... You can't go me tar charge e,«,® 111'I .- an audio amplifier or receiver are not 11]1 l"1 wrong. 1: 'N¡I Master Cherv.I 6enkAmeriu d .,)1:1 1 q, restricted to use with tape decks, honored on mail orden CAM noise -reduction units, and record Fill out this coupon and mail to address 1111 _, pp11JIIt.1 SNURE I players. All manner of input equip- latest Free Catalogs. MARAXT2 "'`u; below for our PIONEER ment can be utilized, such as rhythm A.A SONY Ó°1s Name u-sis _ boxes. A new device I recently disco- ,'.-3¡::..::.,.r« DUAL MAO Address vered is a harmonica pickup designed

City to be used with most Chromatic har- DIXIE HI- FIDELITY PE -1 monicas. It plugs into the Aux jack and State Zp 5600 Second St., N. E., Washington, D. C. 20011 Phone: 1- 202-6354900 you'd be astonished at the "big AUDIO CATALOG MUSICAL INSTRUMENT CATALOG Please rush me your FREE Audio Catalog and sound" it makes possible. Frequency complete information. I understand mere is no PE-1 obligation. response is said to be 500 to 14,000

Name Hz; output, -57 dB; impedance, 90 Address kilohms; volume control, a 1 -meg STEREO, City linear pot. A kit is available for $24.95 State Zip (about 1/2 the price of an assembled DISCO= TIERS 377 7A AYLESBURY ROAD TIMONIUM, MD. 21093 unit) from Barrie Sound Studios, [301] 252 -6880 W. Montgomery Ave., North Wales, PA CIRCLE NO. 55 ON FREE INFORMATION CARD 19454. 28 POPULAR ELECTRONICS

www.americanradiohistory.com INDEPENDENCE Gutter Mount An:enna Model 17 -245 Lcw- profile 21 " stain ess steel . . . . . "Breaker Breaker ." whip antenna with stalk arrestor and flex -matic shock spring. Fits practicallf any Break- through with vehicle rain gutter. No inter - feence with door open ng or passenger exit. Heavy -duty molded clamp bracket insu- BREAKER! la:es and supports an enna. Center loaded ABS load coil foexcellent transmissicn and The New Freedom Line of CB Mobile and Base Antennas reception. 14' coaxial cable and Accessories made in the U.S.A. for communications be- with solderless connector and gt.ick- disconnect PL -259 plug. tween peop'e. Complete with corrosion -e- A wide selection of "revolutionary" new CB High Efficiency sistant mount ng hardware. communica :ions antennas of superior strength, electronically and physically, for- all the talk power your CB rig will deliver -coming and going in the 27 Megahertz frequency band. Mobile B-eaker antennas for cars, trucks, trailers, sports cars, station wagons, motorcycles, boats. Breaker base station antennas to communicate with mobiles and hand helds ... all designed specifically for the outstanding transmission PAUL REVERE and reception of CB signals. Roof Mount Artenna The high quality and materials of the Breaker CB antennas Model 10 -215 and accessories assure you the maximum in performance for 42' - many years and at reasonable cost. Performance -tested Special "power- plus" base loaded roof moun wi :h long - Breaker CB antennas offer you these advantages plus more: THE PATRIOT life stainless steel whip. tugged Omni -directional stainless steel shock spring * Easily adjust for lowest VSWR and nigh- quality 16-ft. shielded 1/4 -Wave Base Antenna Long -life stainless steel and fiberglass whips coax cable and sol lerless con- * Model 11 -101 Highest quality coaxial cable with solderless connections nections for fast 'on- the -air" * High in quality, perfo installation. Named after the * Innovative engineering designs mange and efficiency, famed commJnicator and hero * Packaged for quick, easy installation to get you on the a 'r low in cost. Has three of revolu:ionary ers. fast, complete with cables and hardware 108" quarter wave tubular aluminum radials All Breaker antennas are American made in Arlington, plus a gt.arter-wave ra- Texas. In keeping with the tradition of the Bi- Centennial they diator (vertical element). are proudly named after our revolutionary heroes and places. Heavy -duty U -clamp fils Red, white and blue are also the colors of Breaker. Chosen mas: jp to 15/a" diameter. Built -in lightning are heritage and because we too very proud of our contribu- protector. SO -239 sty e tion to making exciting products for use by people com- connector mount. Mates municating with people. See and buy the Freedom line of with PL -259 plug. Shunt Breaker antennas and accessories at your nearest electronic loaded coil. Heavy duly distributor. _ook for the red, white and blue packaging. insu ated molded clamp bracket. Easy to assemble and dis- assemble. WRITE FOR FREE CATALOG. Fixed construction.

GEORGE WASHINGTON West Coast Mirror Mount Dual Truck, RV Antennas THE MINUTEMAN Model 10-200 Truk Mont Antenna Model 10-230 Weather resistant dual 57" stainless steel wnip anten- Stt:rcy, durable, no-hole required it nas with static arrestor tips. .rune of vehicle. Super 44" stainless Secure horizontal cr verti- stee whip, base loaded ow- profile an- cal mounting to West Coast tenna with s ainless shock absoroinc side view truck type mir- spring, chrome plated brass bell hous- rors. Twin antennas co- irg, 18 -foot shielded coaxial cable anc phased for more directional solderless connections. power and easily adjustable for fine tuning. Hermetical- ly sealed, white oversized ABS center load. Cual 18' low -loss coaxial phasing harnesses with solderless connectors and quick disconnect PL -259 plugs. Com- plete with corrosion resistant mounting hardware.

CORPORATION 1101 Great Southwest Parkway Arlington, Texas 76011

CIACEE NO 61 ON FREE INFORMATION CARO

www.americanradiohistory.com Advanced Electronics

The best way to qualify for top positions and top pay in electronics is obviously with college -level training. The person with such training usually steps more If quickly into an engineering level posi- you tion and is paid considerably more than the average technician who has been on the job several years. A regular college engineering program, however, means several years of full -time resident training -and it often means waiting several years before you can't can even start your career. This, of course, is difficult if you must work full time to support yourself and your family. If your career in electronics is limited without college -level training, take a look at the advantages a CREI home to college study program can offer you. 1. Convenient Training CREI brings the college to you. Through the convenience of home study, you receive exactly the same level of for training you will find in any college or your university offering programs in electronic engineering technology. With CREI, however, you can "go to college" whenever you have spare time at home or on the job. in 2. Specialized Programs career With CREI, you enjoy the advantage of specialized training. That is, your program will include only those courses directly applicable to your career in electronics. We omit such courses as English, social studies and other subjects, which are usually required in electronics resident schools. with Therefore, CREI, you move ahead faster to the more interesting and useful part of your training. 3. Practical Engineering CREI programs give you a practical read this! engineering knowledge of electronics. That is, each part of your training is planned for your "use on the job." By using your training, you reinforce the CREI brings college -level training learning process. And by demonstrating your increased knowledge to your em- to you with eight educational ployer, you may qualify for faster career advancement. advantages, including special 4. Engineering Degrees CREI offers you a number of special arrangements for engineering degrees arrangements for earning engineering degrees at recognized colleges and universities. You can earn college credit while you are taking your CREI program or apply later, whatever is best for your career plans.

30 POPULAR ELECTRONICS

www.americanradiohistory.com Career Training at Home

5. Unique Laboratory FREE Book Qualifications Only CREI offers you the unique Elec- There isn't room here to give you all of You may be eligible to take a CREI tronic Design Laboratory Program. This the facts about career opportunities in college -level program in electronics if complete college laboratory makes learn- advanced electronics and how CREI you are a high school graduate (or the ing advanced electronics easier and it prepares you for them. So we invite true equivalent) and have previous gives you extensive practical experience you to send for our free catalog (if you training or experience in electronics. in many areas of engineering, including are qual.fied). This fully illustrated, 80 Program arrangements are available de- design of electronic circuits. No other page catalog describes in detail the pro- pending upon whether you have exten- school offers this unique program. It is a grams, equipment and services of CREI. sive or minimum experience in elec- better "Lab" than we have found in tronics. many colleges. And the professional equipment included in the program becomes yours to keep and use throughout your professional career. Send for this FREE Book 6. Wide Program Choice describing your CREI gives you a choice of specializa- opportunities tion in 14 areas of electronics. You can select exactly the area of electronics best and CREI college -level for your career field. You can specialize in such areas as computer electronics, programs in electronics communications engineering, microwave, CATV, television (broadcast) engineering and many other areas of modern electronics.

_, 1" tip 1` = 7. Prepared -s- + _ by Experts adanG G_ `' Experts in industry and technical organizations of government develop CREI programs. Each part of your training is developed by a recognized expert in that area of electronics. That means you get the most up -to -date and practical instruction for your career. 8. Industry Recognition That CREI training is recognized by industry and government is evident from the fact CREI provides training to advanced technical personnel in over 1,700 technical organizations. Many sub- sidize the training of their employees with CREI. If there is any question about the advantages of CREI training for you, ask your employer or any engineer to evaluate the outline of a CREI program for you. Other Advantages Ot course, there are many other advantages to CREI training. For ex- Mail card or write describing qualifications to ample, throughout your training, CREI's GI Bill staff gives you personal instruction for (REI programs each step of your program. And in ICAPITOL are approved many industrial areas, both in the U. S. RADIO for training of and abroad, CREI Field Service Repre- ENGINEERING veterans and sentatives provide a number of impor- servicemen under tant personal services for your training INSTITUTE the G.I. Bill. and your career. McGraw -Hill Continuing Education Center 3939 Wisconsin Avenue Northwest Washington, D.C. 20016 Accredited Member National Home Study Council

JANUARY 1976 33

www.americanradiohistory.com BEEN DISSATISFIED IN THE PAST?

HERE'S A PRESENT FROM THE FUTURE.

This is our Criterion 2005 Heil Air -Motion Transformer Speaker System. Incredible purity, astonishing clarity and definition are achieved through the use of the Heil Air -Motion Transformer Tweeter. Taste- fully encased in a simple, uncluttered column, the 2005's "corona field" Heil Air -Motion Transformer reveals every important characteristic that the ear has been longing to hear. The 2005 offers outstanding dispersion to the highest frequencies, essentially flat response to beyond 22,000 Hz and complete freedom from fatigue producing distortion. The 2005 has a continuously variable control allowing infinite high frequency adjustment to balance with the acoustics of any room. Advanced engineering, outstanding performance and uncluttered styling. You'll find them all in the 2005. And you'll find the 2005 in any of our coast -to -coast electronic shopping centers and associated stores. 19995

ELECTRONICALLY SPEAKING, WHO KNOWS BETTER THAN

LafayetteR4DI0 ELECTRONICS CENTERS SHOPPING

;c LAFAYETTE RADIO ELECTRONICS CORPORATION 1975

CIRCLE NC 29 ON FREE INFORMATION CARO

www.americanradiohistory.com CONNECTING extension speakers Popular ElectronicsR to one's stereo system or rear January 1976 speakers for a four -channel setup is a terrifying task for many people. It often means running speaker wires through walls and floors, hiding them under a carpet, or tacking them to base- CONSTRUCTION boards. Presented here is a "wireless" system that eliminates this problem! The new system uses existing ac power lines, operating in an FM mode. The result is good -quality audio (wide frequency response and low distortion) and a high order of noise immu- nity. To overcome the old obstacles of the wireless medium (noise, narrow bandwidth, etc.), as in AM wireless intercoms, the Wireless Hi -Fi System employs an FM carrier, phase- locked- loop (PLL) and voltage- controlled- oscillator (vco) IC's. The result claimed by the author is a 30 -to- 17,000 -Hz ±0.2 dB frequency response, 2% total harmonic distortion (THD), and excellent noise im- munity for a fine signal -to -noise (S /N) BY JIM SHERWIN ratio of -50 dB unweighted, at 2 watts power output into an 8 -ohm speaker. (How to achieve higher power output is discussed later in this article.) In addition, putting the signal on the ac line will generally assure good reception A Wireless at all power outlets in your home - even if the transmitter and receiver are on opposite sides of the line. Audio System for Remote Speakers Now you can enjoy high -quality remote sound without running wires around the house.

As structured, the system will ac- About the Circuit. The transmitter, commodate a monophonic signal. To shown schematically in Fig. 1, uses transmit stereo, two systems can be voltage -controlled oscillator ICi to used, each tuned to a different carrier drive the Q1 amplifier. The dc power frequency. The drive signals can be bus is regulated by /C2. taken from the tape monitor and tape Two inputs are provided so that output jacks of your amplifier. If your both left and right channels from a hi -fi system doesn't have these jacks, stereo system can be combined for the signal can be taken from across traismission to a remote speaker sys- the speaker terminals, but the advan- tem. For a monophonic source, resis- tage of a fixed level will be lost. tors R7 and R8 can be eliminated and JANUARY 1976 35

www.americanradiohistory.com CIO

Fig. 1. Two inputs are provided for the transmitter. For a monophonic source, R7 and R8 can be eliminated. 03 1N4002 30Vp CT D2 IN 4002 2 IC2 LM78L12CZ FOR ALTERNATEI [R4 R3 3 INPUT, SEE 22K 18K + + FIG. 2 i1 C9 C6 C12 C9 0--. IOyF I000yF TI .IyF .IyF R7 10K R6 30011 ( INPUTS My_00 C7 C3 01 R8 1000pF 10K C5 6 2200pF ICI 566 RI R5 10K 5.1K

12.2CIyF DI R2 C4 IN 914 150K T Fig. 2. Use the circuit *CARRIER FRED: 200 kHz : C4 =82pF: C7 1000 pF below to provide :loco kHz :C4= 16QpF:C7= 3900pF preemphasis for the transmitter in Fig. I. TRANSMITTER PARTS LIST QI- 2N2222A transistor R1- 10,000 -ohm pc -type potentiometer C I ,C 13 *- 2.2 -NF, 50 -volt electrolytic RI I *- I- megohm pc -type potentiometer capacitor The following resistors are Ih watt: C2 *-420 -pF mica capacitor R2- 150,000 ohms, 10% C3- 1000 -pF disc capacitor R3-22,000 ohms, 10% R9 cif-) I R4,R12 18,000 ohms, 5% 100 1( C4-See Fig. for value *- C5- 2200 -pF disc capacitor R5 -5100 ohms, C6- 1000 -µF, 25 -volt electrolytic capac- R6-300 ohms, 5% IN?UT ci itor R7, R8- 10,000 ohms. 10% C7 -See Fig. 1 for value R9 *, RI0 *- 100,000 ohms, 10% C8 ,C 10.0 I I .C12-0.1-pF. 200 -volt film TI- Line -coupling transformer (see text) RIO RII 100K IM capacitor T2-Power transformer with 30 -volt cen- C9- 10 -pF, 16 -volt electrolytic capacitor ter- tapped, 50 -mA secondary (Triad No. DI -1N914 silicon diode F133P or similar) POPULAR ELECTRONICS' per- D2,D3- IN4002 rectifier diode Misc.- Printed circuit board; line cord; formance tests verified that the SIN ICI -5660 voltage -controlled oscillator machine hardware; hookup wire; sol- integrated circuit der; etc. ratio measured 65 dB, exceeding IC2- 78L12CZ -12 -volt regulator inte- *Optional preemphasis circuit compo- the author's claimed 50 dB. With grated circuit nents. IC3 * -741C operational amplifier inte- Note -See Fig. 3 Parts List for availability "A" weighting it was 93 dB. At 0.9 grated circuit. of parts. W, distortion was 0.98 %; at 2.5 W, it was 4.9 %. Frequency response was 30 to 17,000 Hz ±0.5 dB-Ed. degree of isolation required. The work. Of course, if preemphasis is in- parallel combination R12 -C2 will troduced in the transmitter, deem - the input signal fed directly to the top smooth out the frequency response of phasis must then be incorporated into of potentiometer R1. If you want to use the system. To make up for losses in the receiver. the system to feed one channel from a the RC combination, gain is provided The free -running frequency, f,., of stereo system to the other side of the (between unity and 10) by op amp IC1. voltage -controlled oscillator IC1 in room, for example, omit R8 and install Gain is,controlled by feedback resistor Fig. 1 is determined by the values of R4 a 470 -pF capacitor across R7. This will R11. and C4. The sensitivity of the vco with improve the frequency response so Because the system's noise immun- the biasing shown and a V,.,. of +12 that it goes out to about 20,000 Hz. ity is good, no preemphasis /deem- volts is about -±0.66f,. /V. For minimum The alternate input circuit shown in phasis is required. However, if you distortion, the deviation should be li- Fig. 2 should be used in either of two wish to experiment, the alternate in- mited to ±10 %, which means that the situations. First, if you are tapping the put circuit should be used, with a maximum input signal level at pin 5 of signal(s) from a high- impedance higher RC time constant. For standard IC1 should be 0.3 volt peak -to -peak. source, the 10,000 -ohm resistor(s) 75 -µs preemphasis, R12 should be The output voltage from the tape could load down the driving signal in a changed to 180,000 ohms. Then, all monitor or tape output jack of an mono circuit, or introduce unaccept- program material above 2120 Hz will audio system may range from 0.4 to able crosstalk between the -two chan- be emphasized before it enters the 1.5 volts rms; therefore, R1 is provided nels of a stereo system (as applied to transmitter. As above, op amp IC1 so that an appropriate modulation the main power amplifier). If so, the provides gain (set by Ri1) to balance level can be set. circuit of Fig. 2 will provide the higher out losses in the preemphasis net- The frequency -modulated output at

36 POPULAR ELECTRONICS

www.americanradiohistory.com pin 3 of ICI is roughly a 6-volt peak - is coupled to the power line via C8 and transients. In addition, the receiver to -peak square wave. This signal is C12. must also provide an audio mute in the used to modulate the Q1 r -f oscillator, Note that Fig. 1 specifies values for absence of a carrier. which uses tuned transformer Tl as its C4 and C7 for either 100- or 200 -kHz The circuit shown in Fig. 3 picks up collector load. Because Tl is tuned to operation. Also note that capacitors the incoming FM signal and tunes to f,. by adjusting its slug and C7, it serves CIO and C11 are connected across the carrier frequency via the T1IC2 cir- as a high- impedance collector load, rectifier diodes D2 and D3. These cuit. This signal is then applied to a which eliminates the need for addi- capacitors reduce the small step two -stage limiting amplifier (corn- tional current limiting for Q1. Because transient that might be present across posed of elements inside transistor the collector signal can have as much the silicon diodes whose upper har- array Q1), phase -locked loop ICI, as a 50 -volt peak -to -peak amplitude, monics fall within the frequency of in- audio amplifier IC2, and a mute circuit Q1 's breakdown point must be high. terest. made up of QIE and discrete transis- The transistor specified for Q1 in the The job of the receiver is to amplify, tor Q2. Parts List has a 60 -volt breakdown to limit, and demodulate the received FM The FM carrier is coupled to the provide a margin of safety. The mod- signal riding on the ac power line primary of tuned transformer Tl ulated r -f output from the transmitter which can have high -amplitude noise through Cl and C21. The secondary of

Fig. 3. In the receiver, the value of C10 must be increased for de- emphasis, if preemphasis is used in transmitter. C20

N D2 1N4002 28.6V CT C19

01A -OIE = LM3046 *CARRIER FRED: 200 kHz :C2. 1000pF :C13 =300pF D :100 kHz :C2= 3900pF:C13 =620pF 117 VAC D3 IN4002

+12 VOLT BUS 2 CI .IyF C I8 -y =1111. RKi R51 1R6 R8 2.2yF C17 I. 6.2K 6.2K 51001. IOOOpF R12 CB RI6 3.9K IOK pF / - I 3 ICI 4 C21 LM56 2N4248 ,IyF IyF C 9 I 7 8 TC13*

R9 10K

I C12 1000P F

IN91D4 g RIO RII R14 R13 RIS C11 C16 1.8K IK 620 620 33K 2200pF 4 4703F 8 +4 VOLT C9 14 .IyF 3,4, 5 RI8 9,10, 2.711 811 R3 R4 12 (HE CIO 11,12, R7 R17 SPKR 3 82011 16K 36011 C6) ( ^IOOpF 13 2.2yF IM 47T (SEE 14 C 15 TEXT) 473F IyF

RECEIVER PARTS LIST IC2 -LM380 audio amplifier integrated R17- l- megohm potentiometer circuit (National) TI- Line -coupling transformer (see text) IC3- 78LI2CZ I2 -volt regulator inte- T2-Power transformer with 26.8 -volt C I ,C9,C 19,C20,C2I- 0.1 -pF, 200 -volt grated circuit center- tapped, I- ampere secondary film capacitor QI (A to E)-LM3046 transistor array (Triad No. F4OX or similar) Fig. 3 value Printed circuit board; line cord; C2 -See for (National) Misc.- C3,C 14-47 -pF, 16 -volt electrolytic capac- machine hardware; hookup wire; sol- itor Q2- 2N4248 transistor. der: etc. C4-Not used The following resistors are Ih watt: Note -The following items are available C5,C7,C 15- 0.1 -NF, 25 -volt disc capacitor RI -3600 ohms, 5% from American Scientific Corp., 1957 C6,C 18- 2.2 -pF, 25 -volt electrolytic R2 -1200 ohms, 5% Old Middlefield Rd., Mountain View. capacitor R3 -820 ohms, 5% CA 94043: etched and drilled transmitter C8, C12- 1000 -pF disc capacitor R4 -1600 ohms. 5% pc board for $3; etched and drilled re- C 10- 100 -pF disc capacitor (see text) R5,R6 --6200 Ohms, 5% ceiver pc board for $5.50; transmitter C I 1- 2200 -pF disc capacitor R7 -360 ohms. 5% IC's and transistors and Toko line - C13-See Fig. 3 for value R8 -510 ohms. 5% coupling transformer for $6.00; receiver Cl6 470 -pF, 25 -volt electrolytic capac- R9- 10.000 ohms. 10% IC's and transistors and Toko trans- itor R10-1800 ohms, 5% former for $10.50; complete transmitter C17- 1000 -pF, 25 -volt electrolytic capac- RI 1 -1000 ohms, 5% kit for $18.95, plus $1.00 shipping; com- itor R12-3900 ohms, 10% plete electronics receiver kit for $27.95, D1 -1N914 silicon diode R 13, R I4 -620 ohms. 5% plus $1.00 shipping. National Semicon- D2,D3- 1N4002 rectifier diode R15-33,000 ohms, 10% cuctor IC's are available. singly or in - IC 1 -565C phase -locked loop integrated R18-2.7 ohms, 10% quantity from OEMorsco. 2403 Charles circuit RI6 -10,000 -ohm pc -type potentiometer Un Rd., Mountain View. CA 94043. JANUARY 1976 37

www.americanradiohistory.com AC CONTROL amplifier is applied directly to the rier by the choice of value for C13 and mute detector, Q2, but is reduced to setting of R16. TO CI7t about 1 volt by the attenuator consist- If 75- microsecond preemphasis is ing of R12 and R14 before being ap- used, increase the value of C10 to 2200 plied to PLL IC1. pF. Increasing this capacitor's value The PLL operates as a narrow -band will reduce the carrier level in the FROM JUNCTION filter that tracks the incoming FM audio line at the expense of high - R15- CIO signal and provides a low- distortion frequency audio response. demodulated audio output whose The mute circuit quiets the receiver signal -to -noise (S /N) ratio is high. The when no carrier is present. Without OUTPUT TO AMP oscillator inside the PLL is set to free - this circuit. an excessive noise level run at a frequency near that of the car- would result as the PLL attempts to

Fig. 4. Use this clrcrrit to chage receirer orttpnt for more power.

T1 is tuned by C2, while R1 lowers the Q of the circuit to permit it to accept the ±10% modulation and to prevent excessive ringing on noise spikes. Such ringing would cause the mute circuit to deactivate. The secondary of Ti is tapped to match the input impedance of Q1A. The recovered carrier at the secondary of Ti can have an amplitude of between 0.2 and 45 volts peak -to -peak. The 17:1 turns ratio from the full secondary to the tap reduces the amplitude of the recovered carrier so that the base of Q1A "sees" a signal that ranges from 12 mV to 2.6 volts peak -to -peak. The two -stage limiter amplifier composed of Q1A through Q1D operates as a fairly fast comparator whose slew rate is about 70 volts /µs and gain is about 3000. The output from this limiter is a roughly 7 -volt peak -to -peak square wave that has rise and fall times of 100 ns. (Any fairly fast comparator that delivers more than 5 volts output could be used as the limiting amplifier. However, the transistor array specified is a low -cost item that has the advantage of containing an extra -high beta transistor, Q1E, which is used as the mute switch.) The 7 -volt peak -to -peak output of the limiting A

2 IC2 D3 Fig. :;. EtYhirrrt rrrrrl rlrilli,u/ grticlr, for -C4- TI V thr lrrrrrsrrritter are shnrrrr nbuce (A). -R5- ICI Cnrrrporrelrt placerrrerrt./òr stalulcncl trnrr.tir>ritter Cl RI Q -05- R4 is (It left (B). If pre-emphasis is ',sot, DI- (Ile euirrpnrrerrl placenrrrrt -C3 - -C3- - R2 -R3- -C6- -R2- - R3- at right is rrec>ssrir/1 (e). -R12- C2CI< C9 CII

T2 D3 I I 2 R9 RIO R8 R7 IC3

I V II I CIO I TS - INPUTS n C13 t-- C 38 POPULAR ELECTRONICS

www.americanradiohistory.com lock onto noise spikes when the transmitter is shut off. The mute detector is composed fo C7, D1, and 02. Note that an emitter -follower transistor stage is used in place of a diode to give the peak detector a high input and a low output impedance. This

permits the peak detector to shunt 1 to 2 mA of bias away from 01E, without loading the limiter amplifier. With no carrier present, the -4 -volt line biases Q1E into conduction via R10and R11. shorting the audio signal to ground. When a carrier is present. the 7 -volt square wave from the limiter amplifier is peak detected, producing a negative output that is integrated by R9 and C7, averaged by R10 across C7, and further integrated by C6 and R11. The resultant -4 -volt output sub- tracts from the 4 -volt bias to deprive Q1E of base current. This transistor cuts off and allows the demodulated audio signal to pass to the audio amplifier. Peak detector integration and averaging prevents random noise spikes from deactivating the mute when no carrier is present. Audio amplifier /C2 supplies about 2 watts of audio power to an 8 -ohm speaker connected across the output of the receiver. Although this amount of power is adequate for casual and background -music listening, if you want to drive relatively inefficient hi -fi speaker systems. you'll have to modify the output of the receiver to drive a hi -fi amplifier. The circuit shown in Fig. 4 does this. To use it, audio power amplifier lC2 is removed from the receiver circuit and the Fig. 4 circuit goes into the receiver as specified. This switching circuit operates from the mute signal so that when the transmitter is switched on, the relay will energize to apply power to the external power amplifier. In this manner. the power amplifier will automatically switch on when a signal is 'eceived.

Standby power is less than 1 watt.

Construction. The transmitter is best assembled on a printed circuit board, the etching and drilling guide for which is shown actual size in Fig. 5A. In Fig. 5B is the component placement diagram for the board, while the detail in Fig. 5C shows the additions and changes to be made when preemphasis is used in the transmitter. When comparing B and C, note that R1 is eliminated from the A former and R11 is installed in the lat- 1i.1. Fig. Etch ing rrml rlrillirrg guirlr .1.or the ter, displaced one pad space to the left rrrrirrr is shown nbnr'r. The component but oriented the same. plru'r'Mr-ul rlirryrnnr Fig. lilil is on rn',ri ¡owe.

JANUARY 1976 39

www.americanradiohistory.com R15- - RS - -RS C12 -R12- - -- C5 -- - R6 - 01

1 C14 ICI -R2- C13 R9 R7 SPKR A tl GND $ DI I RII j -R4- -C7- -R14 - R3- - °2 I 3 V -RIO - C3/ IC2 C18 R13 - IC 3 - C6 7 \

( RÌ8 /I D2\ -C17- C2 --C 16- C20

-C15- CI9 I (

T2 L12] T2 CT SP KR SEC PRI PRI AC LINE '2

Fig. 6B. Component placement diagram for the receiver is shown above. Foil pattern (Fig. 6A) is on previous page.

Line -coupling transformer Tl can set near the center of its range. Rotate Your ears are burning with amplified noise. be made from a 455 -kHz AM i -f trans- R16's wiper slowly in both directions Even though your system is delivering sound accurately, it's also doing an efficient former. In rewinding the turns, the until the PLL loses lock, indicated by a job of pumping out noise ... accurately. secondary is made up of four turns, sharp increase in noise and a distorted Ideally, music should be recreated against a while 154 turns are used in the prim- Note the dead silent background. The Phase Linear output from the receiver. two 1000 accomplishes just that with two unique ary, tapped 29 turns from one end of positions where drop -out occurs; systems: The Auto Correlator Noise the coil. You can use the wire origi- center R16 between these two points. Reduction and the Dynamic Range nally wound on the transformer 41 may to Recovery Systems. or A finer adjustment be required AWG enameled wire for the turns. obtain minimum noise if an SCR light * It improves the overall effective dynamic range and signal /noise ratio 17.5 dB in any As with the transmitter, the receiver dimmer is in operation. stereo system with any stereo source. is best assembled on a printed circuit The final adjustment is for modula- * The Auto Correlator reduces hiss and board. The etching and drilling guide tion amplitude in the transmitter. noise 10 dB without the loss of high and Connect an audio signal source to the frequencies and without pre- encoding. components placement diagram are shown in Fig. 6A & B. input of the transmitter and adjust R1 * The Dynamic Range Recovery System restores 7.5 dB of dynamic range without Line -coupling transformer T1 is for a signal amplitude of about 0.1 volt pumping and swishing. constructed in the same manner as rms maximum at the input (pin 5) of * Plus, it removes hum, rumble and low described for TI in the transmitter, ex- IC1. This can also be accomplished by frequency noises, without the loss of low frequency music. cept that primary is composed of 4 carefully listening to the receiver while * WARRANTY: 3 years, parts and labor turns the secondary 154 turns, tapped adjusting R1 in the transmitter until Even the finest stereo systems are limited in 9 turns from one end. the sound just distorts and then back- performance by the quality and nature of the ing off a little. recording. With the Phase Linear 1000, Adjustments. Make sure that the Because a single transmitter /receiv- these limitations are overcome. Added to any receiver or preamplifier, it gives you the transmitter and receiver are operating er system will suffice for a mono- most significant improvement in sound at the same frequency. (See Figs. 1 phonic sound system or for one chan- reproduction for the money more than ... and 3 for values of frequency- deter- nel of a stereo system, a second re- any other single piece of equipment you could add to your system. Ask your dealer mining components.) Plug the transceiver and transmitter will be required for an audition. The silence is deafening. mitter and receiver into ac outlets and for stereo sound over the wireless use an oscilloscope or ac voltmeter to medium. In this case, one transmit/ check the amplitude of the waveform receive system would be tuned to across the secondary of T1 in the re- 100 kHz and the other to 200 kHz. ceiver. There is no need at this time to You can also use a pair of trans- have the carrier modulated. mit/receive systems for the rear Adjust the slugs in the Ti's in both channels in a 4- channel system to the transmitter and the receiver for avoid running cábles all over your lis- maximum signal amplitude across the tening room. Again, you would use a secondary of T1 in the receiver. If the different carrier frequency for the dif- receiver is to be located some dis- ferent channels. eAa6ie tance from the transmitter or on the One final note: Although we have opposite side of a 117/220 -volt service mentioned using carrier frequencies line, T1 will have to be readjusted in of 100 kHz and 200 kHz for a two Yiwect`t the receiver to maximize rejection of transmit /receive system, this spacing X000 ac line noise. needn't be 100 kHz apart. For most The free frequency of the purposes, a 40 -kHz spacing will do, Phase Linear Corporation, -running while providing maximum fre- 20121 48th Avenue W. PLL in the receiver is trimmed by ad- still Lynnwood, Washington 98036 justing R16, which should initially be quency response from the system. Q

CIRCLE NO. 63 ON FREE INFORMATION CARO 40 POPULAR ELECTRONICS

www.americanradiohistory.com Get into this fascinating new hobby BY DAVID HEISERMAN with a simple homebrew telescope system.

RADIO astronomy has changed In this article, we will discuss radio tant galaxies, dense star clusters, and our understanding of the uni- astronomy in general terms to intro- remnants of exploded star systems. verse. Behind this new science is an duce amateur optical astronomers Consequently, a simple backyard electronic, rather than an optical and non -astronomers to this fascinat- radio telescope can (and does) readily "eye," called the radio telescope. It ing and relatively new hobby. We will respond to colliding galaxies on "the was the radio telescope that first discuss what a radio telescope is and other side of the universe," though it brought to our attention the existence how to listen to the cosmos with a cannot detect radiation from well - of quasars, pulsars, and galaxies that simple homemade telescope. known stars like Vega and Sirius. seem to disappear at the very brink of Furthermore, a simple radio telescope space and time. Tuning In the Stars. The stars that can pick up radiation from sources Shortly after World War II, radio as- fill the nighttime skies with their twin- that are optically obscured by clouds tronomy became a serious science. kling blue -white light visible to the of gas and dust, a condition that exists The wartime effort brought tremen- human eye emit electromagnetic when an optical telescope is turned dous advances in communication and energy in the visible spectrum. It is to toward the center of the Milky Way radar receivers and antennas that had these that the optical astronomer aims galaxy. Also, radio telescopes can the bandwidths, low noise levels, and his telescope. Many large objects in "see" through clouds, air pollution, high gain characteristics required for space also emit electromagnetic and high ambient light at night and radio astronomy. Professional as- energy at longer wavelengths, in the can be used for daylight "viewing." tronomers seized the opportunity to shf, uhf, and even vhf portions of the The universe is literally alive with explore the universe by studying the radio spectrum. Obviously, no optical white -noise radio "static." Every hot radio signatures of planets, stars, and telescope allows the human eye to object -which includes stars, gallax- galaxies. The amateur astronomer, view these wave -lengths. For these, ies, etc. -emits broadband radio however, has shown uncharacteristic you need a radio telescope. energy that has an intensity roughly shyness toward radio astronomy. The real impact of radio astronomy proportional to its temperature. As il- Part of the amateur's reluctance to has not come from matching up light lustrated in Fig. 1, this kind of thermal get involved in radio astronomy has and radio waves from visible stars. radiation rises in intensity through the been the lack of budget -priced "view- Most of the stars visible to the human vhf and uhf parts of the radio spec- ing" equipment. Though this may eye generate relatively low amounts of have been an obstacle in tie past, vhf energy in the radio spectrum. In con- and uhf equipment and devices are trast, the most powerful radio sources Figures 1. 2. and 3 are from the author's book "Radio Astronomy for the Amateur," published by Tab Books, now readily available for amateur use. outside our solar system include dis- Blue Ridge Summit. PA.

JANUARY 1976 41

www.americanradiohistory.com specifications at a lower cost, there is Fig. I. Relative intensity little radio astronomer can of thermal and nonthermal an amateur sources across the spectrum. contribute at 21 cm. Even so, there is a lot for the amateur astronomer to see at the lower vhf and uhf frequencies. The most fruitful working range for amateur radio astronomers is in the vhf and uhf bands where nonthermal and thermal sources have about the same energy levels. The technology is ~0 tiny fairly well established in this range, Fy and few professional radio astronom- o, ers have done work here.

X -RAY MICROWAVE RANGE RANGE VHF RANGE The Radio Telescope. From a block- diagram point of view, a radio SUBATOMIC telescope is little more than a direc- PARTICLE RANGE UHF RANGE tional antenna, wideband receiver, type of recording /readout FREQUENCY and some device. Adding a device for aiming the trum. It reaches a peak just beyond the a "resonant" energy at a constant fre- antenna and calibrating the receiver visible wavelengths. quency of 1.428 GHz. Anywhere there complete the picture. There are also nonthermal sources is hydrogen, this radiation is present. Whenever a radio source in space of radio noise in space. Most such Hence, professional radio astronom- enters the antenna's beam pattern, the sources are created by high -velocity ers have keyed most of their research readout device registers a gradual in- electrons whipping through intense to the 21 -cm band. Unfortunately for crease in noise signal level. The signal magnetic and gravitational fields that amateurs, 21 -cm equipment with the in most cases is pure white -noise sta- surround most stars and galaxies. proper specifications is either too tic. As the source passes through the device Note from Fig. 1 that the intensity of elaborate or too expensive -or center of the beam, the readout nonthermal radiation is highest at the both -for the average amateur's will show a peak noise level. Then, the low end of the vhf radio band. budget. Until microwave equipment noise level drops off as the object Many radio sources in space gener- becomes available with more suitable moves away from the antenna. The ate noise that is both thermal and nonthermal. The significance of this is TABLE 1- ANTENNA AND MOUNTING that an amateur astronomer has the CHARACTERISTICS option of observing the sources anywhere across the radio spectrum. Advantages Disadvantages Some sources, however, tend to generate larger doses of radio energy at Antenna: one end or the other of the spectrum. Multi- element Moderate to high gain; Narrow bandwidth; polarized in The sun and Jupiter are classic exam- beam (YAGI) relatively simple construction; one plane many impedance- matching ples of predominantly nonthermal options sources of radio energy. Beam array High gain; any linear polariza- Mechanically awkward; requires The sun is most powerful radio our tion possible; many impedance - great deal of working space source. While it generates much matching options high- frequency thermal radiation, intense nonthermal signals from sun- Single helix Inherently wideband; circular Mechanically awkward in vhf spots and solar flares make it an ex- polarization; moderate gain; range; polarized in one cellent subject for the novice radio responds to circular or any "sense" (left- or right- handed). plane polarization astronomer. The planet Jupiter is the Mechanically awkward in vhf next strongest radio source. Since it is Helical array Inherently wideband; high gain; range; "sense" conscious. rather cold, its thermal radiation is responds to linearly or circularly polarized signals negligible (as far as amateurs are con- gravita- cerned). Jupiter's powerful Parabolic Extremely directional; Very difficult to build tional field, however, sweeps gigantic reflector high gain swarms of electrons through the planet's upper atmosphere, creating Mounting: noise that can be heard easily on a Fixed Simple construction Not steerable in any plane radio telescope (as low as 21 MHz). Altitude Relatively simple construction Azimuth is fixed con- There is a third class of radiation, Altazimuth Fully steerable Relatively complicated struction; awkward in lower vhf known as the 21 -cm hydrogen line, range; works in horizon coordi- that is of special interest to radio as- nates Hydrogen atoms make up tronomers. Equatorial Fully steerable; work in Complicated construction an overwhelming majority of all the celestial coordinates matter in the universe. They radiate

42 POPULAR ELECTRONICS

www.americanradiohistory.com TABLE 2- RECEIVER CHARACTERISTICS self- contradictory, and run -of- the -mill radio construction projects seldom meet them. Fortunately, Receiver Type Advantages Disadvantages there are some ready -made systems that can do Shortwave High gain; suitable Narrow bandwidth the job. communications converters and pream- Any wideband radio receiver that plifiers available has a sensitivity of 5µV or better is suitable for amateur radio astronomy Commercial FM Good gain; wideband; Restricted to 88- 108 -MHz low noise work. Shortwave communication re- Custom -designed High gain; wide band- Requires know -how to build ceivers can be used, provided they homemade width; low noise and align have a sensitivity on the order of 0.5 µV to make up for their narrow predetec- TV tuner Readily available; Low gain; poor noise figures tion bandwidth. Commercial FM re- wide bandwidth ceivers work rather well in a vhf radio telescope system because most of them have good sensitivity figures and stronger the radio source, the higher to be the hallmark of professional a wide predetection bandwidth. (Inci- the peak signal response. radio astronomy, they are not the best dentally, there is no need to disable Anyone familiar with communica- choice for amateur astronomers, the FM detector or limiter stage to get tion systems will find the purpose of especially newcomers. Considering satisfactory results from an FM re- each element in a radio telescope sys- both practical and theoretical fea- ceiver. The receiver passes wideband tem rather obvious, but a brief sum- tures,.a tuned multi -element beam an- noise whenever there is no carrier mary is in order. The antenna picks up tenna is the best all- around choice for present.) radio signals from remote sources. a vhf radio telescope system, while a It is tempting to try using a uhf TV The antenna mounting steers the an- quad helix array performs better in the receiver to work the uhf end of thé tenna to the point in the skies from uhf range. Table 1 summarizes the ad- radio astronomy spectrum. However, which the signal originates. The re- vantages and disadvantages of an- while TV receivers have the required ceiver then tunes, amplifies, and de- tenna systems in the light of amateur bandwidth, they have intolerably low tects the signal. Finally, the recording radio astronomy. sensitivity figures. The wideband system displays or records the results. Most amateur radio astronomers characteristic never quite makes up The special requirements imposed on find that they spend considerable time for the poor sensitivity, and any at- these common system components, and effort designing, building, and tempt to use a TV receiver is bound to however, require further discussion. debugging the antenna and antenna produce disappointing results. Table The antenna, for example, must mounting system. While receivers and 2 compares the various types of re- have a higher power gain than is nor- recording devices with the necessary ceivers available. mally required for communication specifications are available commer- The data readout or recording de- purposes, and it must be highly direc- cially, the antennas are not. The ulti- vice, the final stage in the system, can tive. Only antennas with gain figures in mate success or failure of a radio as- be as simple as a voltmeter or as com- excess 10 dB of are worth considering tronomy system rests heavily on the plex and expensive as a chart record- for serious radio astronomy work. The quality and proper selection of an an- er. In any case, it must provide infor- major lobe should have a width of no tenna system, making the extra time mation with reasonable precision and greater than 30° between the half - and effort very worthwhile. reliability. Table 3 lists the relative ad- power points. By the same token, the As far as the receiver is concerned, it vantages and disadvantages of three bandwidth of the antenna should be 2 must have high gain, low noise, good types of recording devices. MHz or more. stability, and wide bandwidth. These Few amateur radio astronomers can Although parabolic antennas seem particular requirements are almost resist the temptation of listening to the hissing signals from the cosmos TABLE 3- RECORD /READOUT DEVICE through a loudspeaker. With the nota- CHARACTERISTICS ble exception of signals from Jupiter, radio signals from space are not very exciting to hear. A loudspeaker is Monitor Device Advantages Disadvantages nevertheless a popular kind of aux- iliary "readout" device for Voltmeter Readily available Requires constant attention amateur during recording sessions radiotelescopes. The basic specifications for simple Chart recorder Requires little or no attention Initially expensive radio telescopes are summarized in during recording sessions; Table 4. provides permanent record of raw data Getting Started. Doing anything really useful with a radio telescope re- Tape recorder Requires little or no attention Data must be transcribed quires at least a nodding during recording sessions; acquain- tance provides permanent record with basic astronomy. A radio of raw data; can be used for astronomer must be able to aim his other purposes antenna at a particular target or know what sources are passing through the JANUARY 1976 43

www.americanradiohistory.com DRIVEN ELEMENT

E 4- A -. D E -E -- -

B C c. DIMENSION NET

A - 251/4 B-91/4 REFLECTOR DIRECTORS ELEMENT LENGTH AND SPACING C - 10 54 483/ D 211/4 E 42"x

TO DRIVEN ELEMENT

51 RG -58l U OR RG -8/ U T COAXIAL CABLE 13- ELEMENT J, BEAM ANTENNA l`

24V2 --RG-58/U 11 I- TO BAIUfN ANT FM AC 15 RECEIVER VOLTMETER DRIVEN - ELEMENT DETAILS REF

0n Fig. 2. Block diagram (left) and details 1 TO RECE VER for a 13- element beam antenna (above) for a 110 -MHz radio telescope described in text. BALUN DETAIL

lobe pattern of his antenna at a given natively, you can consult a recent edi- sistor is in the circuit represents the time. So, he must be able to read star tion of The ARRL Antenna Book for receiver's inherent noise level. Switch- maps and interpret prediction tables. antenna construction tips. ing the antenna back into the system However, an experimenter doesn't Fix the antenna mounting so that it will always cause a rise in the noise have to be familiar with astronomy to always aims the boom due south. The level. The increase in noise level rep- set up a simple telescope and get it boom must be mounted so that it can resents the signal level present at the working. be adjusted in altitude (pivot up and antenna. The 110 -MHz radio telescope sys- down). Use a length of RG -58/U coax- The sun is usually the best subject tem illustrated in Fig. 2 can be assem- ial cable to carry the antenna signal to for trying out a new radio telescope, bled for about $30, assuming you al- the input of a moderately good FM re- mainly because it is so easy to find and To ready have an FM receiver and a volt- ceiver. An impedance- matching transis such a powerful radio source. meter. A beginner can assemble this former can be used to match the check out this simple system, adjust that it system, use it to spot a couple of radio 50 -ohm impedance of the anten- the altitude of the antenna so sources, and finally determine for na /cable to the 300 -ohm impe- points directly at the sun when it cross- himself whether or not he wants to dance of the antenna input circuit on es the celestial meridian (an imagi- learn more about astronomy and build most FM receivers. (The matching nary line that runs from directly over- another system suitable for more ex- transformer isn't absolutely necessary head down to the southern horizon). tensive projects. for trial runs.) Then, connect a voltme- Make this initial adjustment about two Although most of the time and ter that has a 1- or 1.5 -volt ac range hours before the crossing is to occur. money involved in this 110 -MHz sys- across the receiver's speaker output All readings described here were tem goes into building the antenna terminals. The meter will now register taken with the receiver tuned to 110 and its mounting, there is really no- the system's output noise level. MHz, as determined with the aid of an thing unusual about it. It is a standard A switch at the antenna input on the r -f signal generator. The treble control 13- element yagi array cut for a center receiver can be used to replace the on the receiver was set to maximum frequency of 110 MHz. The elements antenna with an equivalent -value load and the afc switch to off. The volume can be made from heavy aluminum resistor. Since the resistor generates a control must be set for full audio gain wire and mounted on a boom made up negligible amount of noise, any noise while taking readings, but it can be of 8' (2.5 -m) long sections of 11/2" detected by the voltmeter while the returned down at other times if the hiss- (3.8 -cm) diameter aluminum tubing. Mount the boom assembly on a stan- TABLE 4 -BASIC SPECIFICATIONS FOR SIMPLE dard 2" (5.1 -cm) diameter steel mast to RADIO TELESCOPE raise the balance point of the boom about 16' (5 m) above ground level. Parameter Minimum Nominal Excellent are uncertain Experimenters who Antenna gain 10 dB 15 dB 20 dB about construction techniques for this type of antenna should look up further Receiver sensitivity 5 pV 1 µV 0.5 pV details in Radio Astronomy for the Amateur by this author (TAB Books, Receiver bandwidth 100 kHz 2 MHz 6 MHz Blue Ridge Summit, PA 17214). This book also contains all the information Note: Minimum is capable of detecting signals from sun, Jupiter, Cassiopeia A and you'll need to get seriously into radio galactic plane; nominal and excellent are capable of working at least five sources astronomy on an amateur level. Alter- outside solar system.

ELECTRONICS 44 POPULAR

www.americanradiohistory.com ing sound becomes a nuisance. estimate of the background noise Illustrated in Fig. 3 are the results of Switch to the resistor and note the being picked up by the radio tele- a four -hour recording session identi- voltmeter reading. If possible, use the scope. cal to that described above. The plot- meter's zero- adjust control to set the Take both readings in a similarfash- ted data (solid lines) show signals ar- meter pointer to zero. If this isn't pos- ion at 30- minute intervals over a riving from three different sources: sible, set the pointer for the lowest period of four hours or so. Always note Sagittarius A, Jupiter, and the sun. possible reading and note it on a sheet the time and difference between read- Sagittarius A, a powerful radio source of paper. Now, switch to the antenna ings. When the experiment is com- representing the center of our galaxy, and note the new reading. Subtract pleted, the data should show a distinct was just moving away from the an- the previous (reference) reading from rise in the noise levels as the sun pass- tenna when the session began. Jupiter the new reading to obtain a fairly good es through the beam pattern. then moved into the beam, followed by the sun. Three powerful radio sources are not always lined up in this way, so Fig. 3. Results of an experimenter shouldn't be disap- 30 an experiment with the 110 -MHz radio pointed if his data shows only a single JUPITER SUN SAGITTARIUS A telescope system. response representing the sun. 25 i / Our simple 110 -MHz system is capable of detecting signals from at least 20 , 5 / seven different radio sources of ex- 5 i \ , traterrestrial origin. These include: 15T r v the sun, Jupiter, Sagittarius A, Cas- \ i \ \ , siopeia A, Taurus A, and Virgo A. Elec- \ I tronics experimenters who are un- 10- i \ J i 1 familiar with the locations of the con- stellations listed here can seek the aid 05- 11 , of an experienced amateur as-

1 tronomer. i, o t Our simple radio -astronomy system I 'I I 1 0900 0930 1000 1030 1100 1130 1200 1230 1300 has a secondary application as a LOCAL TIME PREDICTION CURVES bonus. It makes an excellent system »----ARECORDED DATA for FM DX'ing. 4

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SATISFACTION GUARANTEED or money McIntosh Laboratory, Inc. back East Side Station P.O. Box 96 TIGER 500 assembled $53.95 Binghamton, N.Y. 13904 TIGER SST assembled $42.95 SEND Dept. PE . Post Paid in U.S.A. Send check or money order with order to: NAME /r/-Star Corporation TODAY! ADDRESS CITY STATE ZIP P.O. Box 1727 C Grand Junction, Colorado 81501 If you are in a hurry for your catalog please send the coupon to McIntosh. For non rush service send the Reader Service Card to the magazine.

DEALER INQUIRIES INVITED CIRCLE NO. 32 ON FREE INFORMATION CARD CIRCLE NO 58 ON FREE INFORMATION CARD

JANUARY 1976 45

www.americanradiohistory.com oc /AC /RF

VOLTMETER

BUILD A s25 HIGH-FREQUENCY VOLTMETER

Measures up to 90 volts from dc to beyond 20 MHz.

BY THOMAS H. SEAR

There has long been a need for The heart of this meter is a thermal erates a dc voltage that is approxi- an inexpensive, easy -to -use bench converter similar to the type used in mately proportional to the square of instrument that could measure professional instruments to perform the current. (Fig. 1). the voltage levels of signals at fre- voltage calibrations to frequencies of The important characteristic of the quencies into the MHz range. Now, for 1 GHz. The converter is essentially a thermal converter is that its response less than $25 you can build a broad- straight wire heater, which is con- is relatively independent of waveform band voltmeter that accurately meas- nected in series with the current to be and frequency variations. The unit ures from dc to frequencies over 20 measured, and a thermocouple that used in this voltmeter is designed to MHz at amplitudes up to 90 volts in five measures the mid -point temperature operate between dc and 10 MHz with overlapping voltage ranges. of the heater. The thermocouple gen- excellent accuracy and up to 65 MHz with only a 3% error. To get accurate 2511.0 .5 results at, say, 65 MHz, a more sophisticated construction of the converter .9 would be required.

20 .8 .4 How It Works. As shown in Fig. 2, R1 .7 through R4 make up a voltage divider, with value§ selected to limit the volt- 15 .6 .6 age across TC1, the thermal converter, J ó .5 to 0.45 V. The dc output of TC1 is con- I- nected to the noninverting input of 210 .4 operational amplifier iCi, which is connected as a dc amplifier. Resistors .3 and determine the gain of 1C1, 'LOCATE METER INDICATION - R5 R6 ON BOTTOM SCALE 5 whose output drives M1 a 50 -µA .2 2.MOVE UP TO CURVE 3.MOVE LEFT TO APPLICABLE - meter. Potentiometer R7 is used to VOLTAGE SCALE calibrate the circuit and the meter, while R8 is adjusted to set the zero 0 20 30 40 50 point of the meter movement. METER INDICATION

Fig. 1. Output of thermal converter varies with the Construction. With the exception of square of the input. Use this curve to calibrate meter. the circuit involving the input voltage

46 POPULAR ELECTRONICS

www.americanradiohistory.com divider and TC1, where r -f signals may be present, and all leads should be kept as short as possible, there are no special precautions to be observed in wiring the voltmeter. However, it is ad- visable to keep the r -f and dc portions separated as much as possible to avoid pickup. The IC and resistors can be mounted on perforated phenolic board, with the five connectors, meter, switch, and two potentiometers on the front panel of a suitable enclosure. The resistors in the voltage divider are standard 5% units, R1, R3, and R4 being made up of two resistors either Photo of prototype shows layout of components. in series or parallel, to obtain the required value. The closer you can come Then adjust R8 to set the meter pointer zeroed, connect a known dc voltage to the required value, the better the to zero. to the appropriate input jack. The accuracy of the meter. A precision re- Because TC1 is a thermal device, it 22.5 -volt input (J2) is recommended sistance measuring bridge can be will generate a slight output due to the because calibrating on that range will used to get even better accuracy. ambient temperature. It will also indi- distribute the voltage divider errors cate above zero following each mea- more evenly. Wait about 10 seconds Calibration. Before turning on the surement until it returns to the am- for TC1 to stabilize. Then adjust R7 to power, be sure that the meter needle is bient temperature. For this reason, R8 obtain the correct meter reading as at its zero mark, using the mechanical should not be used to adjust the zero determined by the graph in Fig. 1. The zero adjustment on the meter itself if after each measurement. Use R8 only calibration will be as good as the de- necessary. Set R7 to its center posi- after the temperature has stabilized gree to which the input voltage is tion, turn on the power (S1), and wait a for 5 or 10 minutes. known. (Three fresh 1.5 -volt dry cells few minutes for the circuit to stabilize. With the power on and the meter will provide a calibration voltage very close to 4.8 volts.)

PARTS LIST Caution. Although the circuit is con- servatively designed to protect TC1, BI ,B2-9 -volt battery R5 -1000- ohm,1/2-W, 5% resistor ICI-709 op amp R6- 1- megohm, 1/2-W, 5% resistor the device can be easily damaged by J I to J5 -BNC female connector (Am- R7-250,000 -ohm miniature potentiometer excessive current. Even brief currents phenol UG- 1094/U or similar) R8- 50,000-ohm potentiometer of 5 mA or more in the input divider M 1- 0 -50 -pA meter (Radio Shack 22 -051 Sl -Dpst switch or similar) TC1-Thermal converter (Best Products, circuit can burn out TC1.AIways start R1-13,500-ohm, 1/2-W, 5% resistor (select Ltd., Model S -7. Available from Best measurements using the 90 -V range 56,000 and 18,000 ohms in parallel) Electrics Div., 1211 E. Denny Way, R2 -3600 -ohm, 1/2-W, 5% resistor Seattle, WA 98122 at $10.30 each, plus and move down to the lower ranges R3-720 -ohm, 1/2-W, .5% resistor (680 and postage.) only if the meter indication is 5 divi- 39 ohms in series) holder (2), suitable en- Misc.- Battery sions or less. Never connect a voltage R4-90 -ohm, 1/2-W, 5% resistor (68 and 22 closure (LMB 138), knob (2), mounting ohms in series) hardware, etc. to an input jack when you know the voltage is higher than the range for

JI the am- 90V that jack. Also, never change plitude or frequency of the input sig- VOLTAGE,- II.SK TO 8E nal without first reducing it to zero MEASURED - - 22.5 since transients could damage the R2 thermal converter. 3.6K

BI R6 9V Use. Always remember to allow the R3 50K 72011 ZERO voltmeter to warm up for a few ADJUST - 0.9V B2-.- minutes. 9V R4 Keep in mind that the meter's re- 9011 SIB JS peatability may be an order of mag- 0.45V most to R6 nitude better than instruments YEL IM RED which you may compare it. To avoid confusion, set this meter to a refer- BLK ence indication and then compare it to

YEL another instrument. This voltmeter is TCI RS IK very sensitive in the upper third of the scale, and a small voltage change that may not be noticed on a conventional Fig. 2. Schematic of the voltmeter. Select and combine multimeter can amount to several di- resistors to obtain proper values as given in Parts List. visions on this meter.

JANUARY 1976 47

www.americanradiohistory.com a DIGITAL STOPCLOCK """""'" FOR SHORT AND LONG EVENT TIMING

Times events to 10 hours in 0.1- second intervals. BY MICHAEL S. ROBBINS

12 VOLTS A.C. DI D2 TS? +I ? D3 D4 CIT TC2I

D8 R24 03

M",R25 Q4

R26 05 8 R6 R27 06 26 IC4 28 15 21 R28 19 20 07 25 C6 24 R29 08 23 DI6

161 oJ 14 13 12 Il 10 9 8 7 622 R10-R76 O Q9 R30 C7 - H 0

60Hz O JUMPER Z1 H

411: T T T T Ai I O D9-D15 15 7 II l4 IC2 IC3 O

5 2 6 O 14

14 63 8 1 210 4 5 O pI5

R17-R23

48 POPULAR ELECTRONICS

www.americanradiohistory.com WOULD you like to know precise- former, and either 60= or 50 -Hz line time. The display cycle occurs at ly how long a recording ses- power can be used. Although the 5309 about a 1000 -Hz rate, so that any dis- sion runs; how long it takes to make has outputs for either a 12- or a play flicker is not noticeable. one lap around the track; or how long 24 -hour display, in this case we use Transistors Q1 and Q2 function as that new amplifier has been cooking only a 10 -hour display with the initial an interdigit blanking generator to on the bench? Here is a new six -digit zero blanked and the sixth digit used prevent segment ghosting or after- stopclock that can do it- counting for displaying tenths of a second. (For glow. All segments are shut off for an and displaying elapsed time up to ten example, the display is 9:00:00:0 in- instant before the digits are switched. hours by tenths of a second. stead of 09:00:00.0.) Since IC4 counts in seconds, /C2 The heart of the stopclock is the new Later in this article, we will describe and IC3 are required to provide a 0.1 -s National Semiconductor MM5309 some practical circuits to use in account. The first section of IC2 divides PMOS integrated circuit. It is identical tuating the stopclock for timing differ- the 60 -Hz line frequency down to 10 to the MM5311 -5314 series of clock ent types of events. Hz, while the second section counts IC's with one important exception. the 10 -Hz pulses and delivers a BCD The "hold" pin has been replaced by a How It Works. As shown in Fig. 1, output. The count is repetitive, going "reset" pin, which allows all of the the output of IC4 is in a multiplex from zero through nine. The reset line counters to be reset to zero. This seven -segment format, with each LED of IC2 (pin 7) is connected to the reset means that all of the on -chip counters display turned on for one -sixth of the line of IC4 (pin 16) to insure that the can be reset to zero as required in a display cycle. The seven segment lines two IC's count in synchronism after stopclock. coming from Q9 through Q15 carry the both are reset. In this project the 5309 is used with segment information to all six digits To display the output of IC2, the three other IC's to provide 0.1 -s count- (DIS1 through DIS6), while the six BCD signal must be converted to a ing with stop, start, and reset controls. digit -enable lines coming from Q3 seven -segment format. This is per- Power is provided by a 12 -volt trans- through Q8 turn on the digits one at a formed by 1C3. To eliminate the need

PARTS LIST C3- 0.02 -µF disc capacitor C4,C7- 0.0I -µF disc capacitor C6- 0.002 -pF disc capacitor C 1- 2000 -NF, 16 -volt electrolytic DI through D4- 1N4001 rectifier diode capacitor D5 through D16 -1N914 switching diode C2,C5- O.1 -NF, 20 -volt disc capacitor IC I- CD4023AE (RCA) or MC 14023CP (Motorola) integrated circuit IC2-MC14566CP (Motorola) integrated circuit IC3-MC 14511CP (Motorola) integrated circuit IC4- MM5309 (National) integrated circuit DIS1 through DIS6- Seven- segment LED display (Litronix DL747 or similar) QI,Q2,Q9 through Q15- 2N5172, " MPS5172, or MPSA20 transistor Q3 through Q8- 2N4403 transistor The following resistors I/ watt, 10%: R1,R2,R3,R30 -1000 ohms R4,R6,R7- 100,000 ohms R5,R17 through R23- 10,000 ohms R8,R9-470,000 ohms R31 RIO through R16-2000 ohms R24 through R29-470 ohms R31 through R37 -120 ohms R3Ì R38-270 ohms SI,S2,S3- Normally -open spst pushbutton switch R33 TSI- Two -lug screw -type terminal strip TS2- Four -lug screw -type terminal strip Misc.-Chassis box; printed circuit R34 boards (2); 74 Molex Soldercons or one 28 -pin, two I6 -pin, and one 14 -pin IC 2 L (optional); R35 sockets; small brackets DIS I DIS 2 DIS 3 DIS 4 DIS 5 DIS G four spacers; four rubber feet; red acrylic display filter; machine hardware; R36 hookup wire, solder; etc. Note: The following are available from Caringella Electronics, Inc., P.O. Box R37 727, Upland, CA 91786: etched and drilled main pc board No. DSC -1PC for R38 $7.95; etched and drilled display board No. DSC -IAPC for $6.95; complete kit of parts, including cabinet, hardware, etc., No. DCS -IK for $74.95 plus $2 shipping. California residents, please Fig. I. Complete schematic of stopclock is shown above and on add 6% sales tax on all items. There are opposite page. no kits available for the circuits shown in Fig. 4.

JANUARY 1976 49

www.americanradiohistory.com Itltltl .Joce' \ l 1 I 1 Il 1 f'l

o O e ( O O 0 0 0 O

G F D A SIO SI 50.1 Hl M10 MI DP

Fig. 2. Etching and drilling guides with component layout diagrams for the two pc boards.

50 POPULAR ELECTRONICS

www.americanradiohistory.com for additional transistors to drive the wire connected between similarly Bear in mind that each of the three 0.1 -s display (DIS6), the outputs of labelled pads on both boards. Solder circuits operated by the pushbutton IC3 are connected through D9 5" (12.7 -cm) lengths of hookup wire to switches in Fig. 1 is held at +12 volts through D15 to the outputs of IC4. the pads identified in Fig. 2 by the let- by R1, R2, and R3. To enable an input, Since IC4 is off due to the leading -zero ters H through L. the bottom ends of these resistors blanking interval when it would nor- Fasten the display board to the main must be connected to ground. There- mally display the 10's of hours, this board with two small L brackets, fore, any external switching device time slot can be used for the 0.1 -s dis- threaded spacers, and machine connected to TS2 must have an on re- play. Thus, the H10 output of IC4 is screws; and mount another pair of sistance of less than 100 ohms and an used to turn on and off IC3 and enable spacers at the back of the main board. off resistance in excess of 10,000 DIS6. Then mount the entire assembly in- ohms. In the momentary -on condition, Now, what happens when the H10 side the chassis box, via the spacers, the external switching device must be 10's of hours display is supposed to be with four machine screws and lock - capable of handling 12 mA of current. on as it normally would be after a washers. Glue a red acrylic filter behind As shown in Fig. 4A, relay contacts 9:59:59 count? Without IC1, DIS6 the front panel of the chassis box over operated by some remote device can would display a random character. the display "window." Then mount be used to trip any one or more of the One NAND gate in IC1 is used to detect TS1 and TS2 on the rear panel of the 51, S2, S3 functions. The circuit is this random digit and reset IC2 and box and Si, S2, and S3 on the top. closed by applying energizing power IC4 to zero. In this manner, the stop - Connect and solder the free ends of to the relay coil. If the relay is a latch- clock is reset 0.2 second after the the wires coming from holes H and I to ing type (mechanical or electrical), 10:00:00 count pulse, thus producing the lugs of TS1 and the free ends of the some means must be provided to open an effective timing range of 9:59:59.9 J, K, L, and M wires to lugs 3, 6, 4, and its contacts after each closure. counts. 5, respectively of TS2. Solder 5" Optoelectronic couplers make ideal The other two gates in IC1 are con- lengths of hookup wire to each of the interfaces for the stopclock whenever nected as an RS latch to turn on and lugs on TS2 and wire them to the the controlling circuit is at a different off the time base. Operating S2 causes switches as shown in Fig. 1. Label TS1 voltage from that used in the timer's pin 9 of ICI to drop to zero. Diode D7 is 12voLTsAcand lugs 3through 6on TS2 circuit or has potentially damaging then forward biased, preventing the ac STOP, START, RESET, and GROUND, respec- spikes. An optoelectronic coupler signal from reaching 1C2 and IC4. tively. Then label switches Si, S2, and consists of a light source (usually a Operating S1 raises pin 9 to about 12 S3 STOP, START, and RESET, respectively. LED) and a light sensor (usually a volts and effectively removes D7 from Practicing the usual precautions for phototransistor) facing each other in a the circuit, allowing the ac timing handling MOS devices, install the IC's light -tight case. The source and sen- signal to reach the counters, and the in their respective locations via the sor are electrically isolated from each count changes every 0.1 second. Soldercons or sockets. Make certain other. The Motorola 4N28 optoisola- Jumper Z1 between pins 13 and 14 that you orient them properly. (On the tor, one of the more common types of IC4 causes the input sections of IC2 case of each IC is a dot for easy iden- available, is shown connected to TS2 and IC4 to divide by six for use on the tification of pin 1.) on the stopclock in Fig. 4B. A separate on 60 -Hz power line. For 50-Hz operation, optoisolator circuit can be used no jumper is needed. Operation and Use. When power is each of the START, STOP, and RESET first applied to the stopclock, random inputs. Each is separately tripped by Construction. The stopclock is best numbers will be displayed. Depres- momentarily applying a dc voltage to assembled on two printed circuit sing RESET switch S3 resets all dis- the source circuit. boards, the etching and drilling and plays to zero. When START switch S1 is The circuit in Fig. 4C can be used to component placement guides for momentarily closed, the stopclock Fig. 3. Photo o /'infernal layout. which are shown in Fig. 2. The circuit should begin counting at a 0.1 -s rate Note some resistors are vertical. is split between the main and display and the DIS6 digit should be a blur. boards as shown by the two sections Let the stopclock run for a few min- in Fig. 1. utes. Then hit STOP switch S2. The dis- Leaving installation of the IC's until play should immediately grind to a halt last, wire the main board as shown, and remain locked onto the last count taking care to properly orient the filter after releasing S2. capacitor, diodes, and transistors. To be of any use as an events timer, Note in Fig. 3 that some resistors the stopclock must be stopped and mount upright. Install Molex started in a manner that produces Soldercons or regular IC sockets in meaningful information. The simplest the locations for the IC's, but don't approach would be to use the install the IC's just yet. switches on the top of the cabinet to Next, wire the display board as fol- initiate the count and stop it. For re- lows. First install and solder the resis- mote operation, an identical set of tors into place on the foil side of the pushbutton switches can be con- board. Trim away excess lead lengths. nected to TS2 (paralleling S1, S2, and Then install and solder into place the S3) via a cable. The best way by far of displays, DIS1 through DIS6, on the tripping and stopping the count is to blank side of the board. Interconnect let the event being timed operate the the two boards with lengths of hookup stopclock.

JANUARY 1976 51

www.americanradiohistory.com TS2 measure running (or on) times. Resis- START tor R should be selected to limit the y STOP current through the diode to about 40 100K RESET mA. For example, to measure the running time of a battery- powered cas- ® GND F (A) sette recorder that has a 12 -volt dc TOP VIEW motor, the value selected for the resis- 4N28 tor in ohms is equal to (V- 1.2)/A, I00K 22011 TS2 where V =12 volts and A =40 mA. In START this case, R =270 ohms. The circuit .. connects across the tape recorder's -- STOP IN4001_ motor. ® RESET The length of time it takes a vehicle ® GND (including toy trains and cars) to 2 s traverse a prescribed distance is often of interest. Light -beam tripping is a ( B) convenient way of starting and stop- R wvAAA Ts2 ping the count. The circuit for accom- (SEE TEXT) START plishing this is shown in Fig. 4D. Al- 16 15 STOP most any type of light source, includ- IN4001 4N28 ing an ordinary flashlight, can be used RESET in 2 3J this scheme. Depending on the dis- GND tance between the light source and (C) phototransistor, it may be necessary TS2 to use lenses to focus the beam. START (Lenses may not be necessary in tim- I00K y ....a ing toys unless the distance is more O STOP 2N 5I72 than a few inches.) Although a RESET O Motorola MRD450 phototransistor is ®GND specified in the diagram, the value of (D) the resistor can be adjusted to allow Fig. 4. Stopclock can be operated by a relay (A); the circuit to accommodate just about an optoi.5ulator (B and C); or a (C). phototwrristm any other phototransistor. (you don't have to buy a new car to get an electronic ignition Most of you know the evaluation of automotive electrical sys-

tems . . . an evaluation characterized only occasionally by

efficiency and performance. I know that, and that's why I use the Delta Mark Ten B CDI on all my cars, new and old. And believe me, you don't have to have a new car to appreciate the best electronic ignition available today. Study these fea-

tures and you'll know what I mean. 1. Mark Ten and Mark Ten B Capacitive Discharge Ignition Systems are manufactured by Delta Products, Inc., a company with a conscience, and with a proven record of reliability both in product and in customer relations. 2. The Mark Ten CDI's really do save money by eliminating the need for 2 out of 3 tune -ups. Figure it out for yourself. The first tune -up or two saved pays for the unit. the rest is money in your pocket. No bunk! 3. Because the Mark Ten CDI's keep your car in better tune, you actually can save on expensive gasoline. 4. With a Mark Ten, spark plugs stay clean and last longer ... fouling is virtually eliminated. No matter what kind of car you drive, it too can use a Delta quality lift.

I want to know more about Mark Ten B Col's. Send me complete no- nonsense information on how they can improve the performance of my car. Name Address City State Zip

DELTA PRODUCTS, INC. P.O. Box 1147, Dept. PE, Grand Junction, Colo. 81501 303 -242 -9000

Mark Ten B, Standard Mark Ten,

assembled . . $64.95 ppd assembled . $49.95 ppd Mark Ten B, kit $49.95 ppd Deltakit© $34.95 ppd CIRCLE NO. 16 ON FREE INFORMATION CARD

www.americanradiohistory.com CONSTRUCTION THE PROGRAMMABLE

MUSIC BOX PART 2 How to add 256 words of memory, plus music box applications.

BY MITCHELL WAITE AND LARRY BROWN

In Part 1 of this article, we discussed tender is shown in Fig. 1. Note that a Construction. In Fig. 2 are shown the circuit and construction proce- 16- conductor cable is used to connect the actual -size etching and drilling dure for the basic programmable the memory module to the main music and component placement guides for music box, which contains a 40-note box circuit board. This cable carries the memory extender module. Wire static memory system. This month, we all the required power, clock and the board as shown, reserving installa- will describe a 256 -word memory input /output data. (Power is obtained tion of the IC's for last. Mount and sol- add -on that greatly expands the pro- from the music box.) der into place IC sockets or Molex grammability and playing time of the The clock signal from the music box Soldercons '1 at the IC locations. Then music box. board is fed to Q1, Q2, and Q3, which connect the leads on one end of a Because the music box uses an un- shape the leading edge of the clock length of 16- conductor cable to the addressed shift register for storage, signal to match the requirements of pads labelled 1 through 16 on the increasing the size of the usable memory chips IC1, /C2, and /C3. All memory module. Remove ICi from the memory is simple. The add -on mem- three IC's are clocked simultaneously. basic music box, and solder the free ory system is built around three dual Information is stored when the RECIRC ends of the cable to the same num- 256 -bit shift registers. The entire input is disabled. bered pads in /C/'s location on the memory circuit can be assembled on a The data on input lines /i through /6 main circuit board which is located small printed circuit board and con- changes with instructions from the inside the music box. nected to the music box by a multi - music box. The memory is clocked Next, exercising the usual precau- conductor cable. once for each change. Output lines 01 tions for handling MOS devices, install through 06 feed the stored data back ICi, IC2, and IC3 in their sockets on About the Circuit. The complete to the music box when a tune or the memory board. Check to make schematic diagram of the memory ex- melody is to be played. sure that all IC's, transistors, and Fig. 1. Schematic of the

CLOCKO6 memory extender. Numbered, terminals are connected +V 16 to main board in music bo.r. PARTS LIST 03 RI R3 R4 331( 33K 10K C1- 0.002 -pF, 100 -volt Mylar capacitor 1502 C2- 0.1 -pF, 50 -volt Mylar capacitor 3 DI 05 8 D1 IN4148 or similar diode 01 ICI through D6- 7 1401 527 IC I through IC3 -2527 dual 256 -bit shift 6 04 ? 9 register IC (Signetics) QI,Q3,Q4- 2N4126 or similar transistor Q2- 2N3565 or similar transistor The following resistors are 1/4 watt, 5 %. RI,R3 R9- 33,000 ohms R2 -7500 ohms To R6 PADS R4- 10,000 ohms 15K 2 23015 OF 15,000 ohms ICI R5,R6,R8- 4 ,3 ND3 03010 R7- 47,000 ohms IC2 ON 2527 7 16 MAIN Misc.- Printed circuit board; sockets or BOARD DI- D6= 1N4146 OR SIMILAR 5 6 D4 06 Molex Soldercons for IC's; 16- conductor cable; hookup wire; machine hardware; solder; etc. Note: The following items are available from Cal Kit, P.O. Box 877, Sebastopol, 04 CA 95472: Complete kit of memory ex- 2N4126 I2014 D5 02 tender module parts, including drilled R7 IC3 II and solder-plated pc board, flat 16- 47K 2527 01013 conductor cable, and mounting I 5 6 26 12 hardware, No. MC 1 -6 for $54.00, ICI,

IC2, and IC3, No. MC 1 -8, for $43.00; three IC sockets, No. MCI-11, for R8 R9 $3.00; pc board No. MCI -7 for $8.00; 15K 33K telephone interface kit No. MCI -5 for -I8 V05 $11.00. All items shipped postpaid and insured. California residents, please add RECIRC04 6% sales tax.

JANUARY 1976 53

www.americanradiohistory.com j`( clr'4'0.11-.-;\°Ipo co4211)°:,11.

Photo of memory e,rtrilei' board. rommerao.._ First, record each note above its symbol. Next, determine the duration of the shortest note. In our example, there are two half notes, one quarter note, four eighth notes, and a quarter note. This means that a memory "word" is worth one eighth note, the shortest note in the brief melody. A quarter note will then require two words of memory, a half note four words, and so on. Determine how many words of memory each note requires and write this number beside the note's letter. In our example, "call" and "me" are half notes. Since a half note is the same duration as four eighth notes, the first number is a 4. The next note is for "ir..." (first syllable in "irresponsible"), which is a quarter note, or two Fig. 2. Etching and drilling guide (top) and euiiihuuritI hiitr,iiI. eighth notes long. So, note B has a 2 after it. Continue to do this to all notes until you have used up the melody or diodes are properly oriented. Turn and played. It simply provides an ex- run out of memory. over the circuit board and check all panded memory. soldered connections. Reflow the sol- You can make your own program- NOTE C C D D D D B B D der around any connection that ap- ming form by laying out three horizon- OCTAVE SPACE pears questionable. Finally, check the tal rows of boxes numbered from 1 to IRMOINFI 1 /t./2 3 4 5 6 7 8 9 10 I I 12 board's conductor pattern against the 40forthe40 -word memoryorfrom 1 to

etching and drilling guide in Fig. 2, 256 when the memory extender is D Db C C D D D D E E E CO particularly between the closely used. Label the top row NOTE, the mid- spaced IC pads, for solder bridges. dle OCTAVE, and the bottom SPACE. For W 13 14 W15 16 17 18 19 20 21 22 23 24 25 26 Power requirements for the memory simplicity, leave the OCTAVE and /or iE module are significantly greater than SPACE (remove) squares for each note E E E Eb D D D D * those for the original 40 -note memory. blank if neither switch is to be de- If you decided to use battery power for pressed during programming and the original music box, it will be shade in the boxes where the switch or 1//iOvi 27 28 29 30 31 32 33 34 35 36 37 38 39 40 necessary to use a heavier -duty bat- switches are to be closed. *STOP SWITCH UP SWITCH DOWN tery when the memory extender is As an example of programming, let added. Switch to an Eveready No. 276 us use the first two measures of "Call Program for "Call Me Irresponsible." or RCA No. VS306 heavy -duty 9 -volt Me Irresponsible." In sheet music battery, which should provide about form, they would look like this: Now, determine where the spaces 60 hours of useful life. are to go. The first entry, C, is a half

C43 D43 B21 CIO DII DIO Db10 C21 note. Since it requires four words to Operation. A set of programming create a half note, the first three words forms can simplify writing and storing have no space between them, which melodies in the music box, regardless 41P- -I- b, -0- means the spaces should be removed of which version you build. Note that CALL ME IR - RE - SPON - SI- BLE by operating the SPACE REMOVE Switch the addition of the memory extender on the Music Box. To prevent the last module does not alter the manner in "Call Me Irresponsible" by Sammy Cahn and James Van word from running into the next note, Heusen. Copyright e t962 & 1963 by Paramount Music which the music box is programmed Corp. your programming form should havea

54 POPULAR ELECTRONICS

www.americanradiohistory.com 'IF I WERE A RICH MAN"

E # N D C D C B G FD0# B G G S B C C Eb Gb 0 Program for "I /'I Were A T Rich Malt" from "Fiddler on S the Roofl " Keyboard of the music box. C D E E D D D

(COPYRIGHT 1964 The New York Times Music Corporation (Sunbeam Division). All rights administered by The New York Times Music Corp. Used by Permission. All rights reserved.) SWITCH DOWN [SWITCH UP *STOP S=SPACE

F#E',F'+LEFT F OR F F#", F" e RIGHT F# OR F

blank in the SPACE row. You indicate press the SPACE REMOVE switch and without accented beat. With a little this on your sheet music by entering a hold it, press the WRITE & STEP switch imagination, it can be programmed to 3 after the "C4" entry. The entry "C43" three times, release the SPACE REMOVE play the rhythm accompaniment to is now interpreted as note C with four switch, and press the WRITE & STEP your music. words of memory required and the switch once again. Proceed to the To use the music box as an unusual first three spaces removed.. Continue next note. Programming form for replacement for a conventional door- to calculate where to remove spaces another tune is shown above. bell or chime system, locate and dis- for the rest of the notes in the melody. Applications. With the memory ex- connect the doorbell's pushbutton If a note is to be in the upper octave, tender added to the music box, some switch leads at the transformer. Con- indicate this by underlining the entry interesting programming possibilities nect these two wires to the main cir- on the sheet music form. are possible. You can, for example, cuit board in the music box via pads 36 In our example, the curved line be- write a long melody into the memory. ( +V) and 35 (start). You can then feed tween the two D notes on the scale Alternatively, you can write several the output of the music box to a power forms the "soon" (of "irresponsible "), shorter tunes, which can be played on amplifier to obtain attention -getting which means that the two notes are demand by touching the keyboard volume. run together. Therefore, you must re- probe to the START key or having a If local laws permit, you can build move a space from the first D note. doorbell switch close the same circuit. the music box /telephone interface All that remains now is to enter the If each tune starts with a "stop" code, shown in Fig. 3. The actual -size etch- data onto your programming form. We only one melody will play each time ing and drilling guide and compo- will use only the first note (C43) to il- the start circuit is activated. nents placement diagram for this cir- lustrate how this is done; all other en- Another way you can use the music cuit are shown in Fig. 4. The telephone tries on the form are made in a similar box, in either version, is to program interface detects the 20- to -90 -Hz ring- manner. In the top row, enter a C in the tune you want and accompany it ing voltage that normally operates the boxes 1 through 4. Since the note is on another instrument or by singing phone's bell and uses this voltage to not in the upper octave, leave blank the tune. This approach is better than strike (ionize) neon lamp 11. The lamp the first four blocks in the second row. using a tape recorder because the is optically coupled, via a light -tight You want to remove the spaces be- playback rate of the music box can be shield, to light- dependent resistor tween only the first three eighth notes, increased or slowed down without LDR1. The LDR is connected to the which means you have to fill in the first changing the pitch. (Any time you main board via pads 35 and 36. When three boxes in the bottom row. change the speed of a tape recorder, the ringing signal occurs, the music Programming this note is a rela- you also change the pitch.) box triggers on until the receiver is tively simple procedure. Touch the You can even use the music box as a lifted off the hook or the ringing stops. programming probe to the C key, variable -speed metronome, with or Because the circuit has a high series resistance, it will not interfere with

R57 normal telephone operation. And the Fig. 3. Schematic for a 100K TO optical coupling eliminates any telephone interface tu R58 3 +V 2 D34 D35 go with the music boa. 200K danger to the telephone system by ac- TO cidental hookup of the power supply PHONE LDRI NE-I CL -703 to the ac power line. D37 If you are a radio amateur, you can C17 D36 47pF 4 TO program short Morse code messages, START PAD such as a CQ followed by your call letters. By using a relay in the collector of the audio output circuit, you can Fig. 4. Etching and drilling key a transmitter. guide and component layout You can wire two music boxes so for the telephone interface. that one clock controls both to allow you to play two-note chords in real time. If you have an electronic music synthesizer, you can use the output ` -- lines of the music box to drive the synthesizer's control circuits, creating some interesting sequences not possible with a conventional keyboard.4

JANUARY 1976 55

www.americanradiohistory.com the designer to put both digital and analog circuits on the same chip. Be- cause it uses thoroughly proven man- A New ufacturing techniques, it is low in cost and lends itself to the full range of microcircuit applications. Transistor Evolution of 12L. The advantages of I2L came from shrinking DCTL, shown in Fig. 2, into a compact equivalent structure. The input circuit consists of Logic Family three transistors in parallel. If one or more of these transistors is conduct- ing, they act as short circuits, preventing current from flowing through the load gates. When all input transistors

New techniques provide high speed COMPARISON OF TTL AND FL DEVICES with low power requirements. Parameter I2L TTL

Packing 120 BY WILLIAM D. HAFFNER density -200 20 gates /mm2 gatesimm2 Gate delay 25 -250 ns 10 ns IN A seemingly endless quest for 1. The vertical (npn) transistor oper- Power dissipation 6 nW - 10 mW ever and faster circuits, ates as an inverter, while the lateral smaller (per gate) 70 µW semiconductor researchers have de- (pnp) transistor serves as both the cur- Supply voltage 1 - 15 V 3 - 7.3 V veloped a number of different transis- rent source and load. By contrast, a Logic voltage 0.6 V 5V tor logic families. Among those that typical TTL gate requires six or eight swing have already made their splash are: di- transistors and must have source or Current range 1 nA - 1 mA 2 mA rect- coupled transistor logic (DCTL), load resistors. resistor -transistor logic (RTL), When the I2L gate is formed on sili- are cut off, current flows through the resistor -capacitor transistor logic con, both transistors are merged into load gate transistors. This circuit ac- (RCTL), diode -transistor logic (DTL), the area of a single multiple- emitter tion produces the common NOR logic transistor- transistor logic (TTL), and transistor. This eliminates space - function. most recently metal -oxide semicon- consuming device isolation, which, in By replacing the three load resistors ductor (MOS) and complementary - addition to the absence of resistors, with an active current source, I2L sim- symmetry MOS (CMOS) logic. accounts for 12L's circuit density. That plifies the rather bulky DCTL. Then, density can be up to 100 times greater the transistors with connected bases than is possible with TTL. For exam- are replaced with a multiple -collector PNP NPN ple, as many as 3000 logic gates, or (npn) transistor. This is easy to do be- +v 10,000 bits of memory, can be packed cause all of the DCTL transistors have INJECTOR on a single I2L chip. The table com- a common grounded emitter. In most pares several of the more important I2L gates, a simple pnp transistor parameters for I2L and TTL devices. Perhaps the most revolutionary at- 1 tribute of I2L technology is its versatility. Furthermore, I2L circuits can easily Fig. 1. The npn te( nsistor is an interface with other circuits. It enables inverter; the pnp serges as a current source as well as load.

Now, a promising newcomer has been added to the list. It goes under the name integrated injection logic, or I2L. Said to be as much as two years ahead of the previous state of the art, it employs the same proven manufacturing process as used for TTL. The IC's have high packaging density, have speeds approaching TTL, and con- sume only about a hundredth of the power of equivalent TTL devices. Injection logic achieves its high performance by reducing a logic gate to a single complementary transistor pair Fig. 2. A DCTL circuit which as illustrated by the basic gate in Fig. can be piade smaller using 12L. 56 POPULAR ELECTRONICS

www.americanradiohistory.com (LOGIC INPUT) lated variety that uses a reverse - biased pn junction for component isolation. Since this completely isolates NPN adjacent devices, it is used in I2L chips that contain mixed functions. Such A+B functions as LED drivers, memory de- PNP (LOGIC INPUT) (CURRENT coders, current regulators, op amps, INJECTOR) comparators, oscillators, and TTL or ECL devices can be combined on a single monolithic chip. Texas Instru- ments has in production an isolated I2L digital watch chip that measures Fig. 3. A simple NAND gate using integrated injection logic. 1/8 (3.2 mm) on a side and contains logic, timing, and display drivers. The serves as the active current source by Device Construction. Because of chip is approximately 25% smaller injecting minority carriers into the the common elements described than the typical MOS versions. This emitter of the npn transistor. A light above, the entire I2L gate takes up the chip is being used in a digital watch source can be used for injection in space of a single multiple- emitter made by Benrus. An advantage of I2L electro- optical applications. transistor when laid out on silicon. in this application is that cost can be The refinement of the DCTL gate re- Here's how this is done: reduced by using crystals operating at sults in the complementary transistor The high density of I2L is due in large 4 MHz. This is not possible when using pair shown in Fig. 1. It can be seen that part to its simplicity and economy of CMOS. the base current of the npn transistor design. The n + region in Fig. 4 serves Also on the market is a 100 -ns is common to the collector of the pnp as a common ground plane to inter- medium -performance TI RAM current source, while the base of the connect all grounded- emitter transis- (745209) with I2L gates as the memory current source is common to the emit- tor gates on the chip. The n region and TTL circuits as peripheral inter- ter of the npn transistor. The emitter of above the n+ region is both the emit- face elements. the pnp transistor, called the injector, ter of the vertical (npn) transistor and The second type of device in pro- is common to all I2L gates on a chip. the base of the lateral (pnp) transistor. duction is the nonisolated I2L chip, The circuit shown in Fig. 3 is an ex- The two p regions serve as the base of used in very complex digital IC's. Iso- ample of the simplest version of an I2L the npn transistor and also as the col- lation is not required because all cir- NAND gate. Positive NAND logic is im- lector of the pnp transistor. The two cuits on the chip are I2L devices. Con- plemented by using the multiple - n+ regions are the multiple collector sequently, higher functional density is collector npn transistor as an inverter. of the npn transistor. Finally, metal- achieved when compared to isolated Positive NOR logic can also be per- lized connectors are added to provide I2L chips. The first LSI digital circuit formed by OR'ing the I2L gate outputs. interconnection between the gates. built with nonisolated I2L technology The npn transistor is normally Notice that the pnp transistor is inte- is the Texas Instruments SBP0400 biased on (low output) by the current - grated into the npn transistor. It 4 -bit microprocessor. This chip has injector pnp transistor, which is con- doesn't exist as a discrete component, more than 1450 gates in a single nected between the base of the npn yet it can supply injection current for a 40 -pin IC package. To date, it is the transistor and the external current series of npn gates. most complex standard bipolar chip in source. Switching action is accomp- The result of this manufacturing production. It has features that could lished by steering the injector current. technique is the smallest component be duplicated only by using 30 to 40 This is done by controlling the input size of any current IC manufacturing small- and medium -scale TTL IC's. voltage, V,,,.:, to the gate. A low input technology. The I2L gate is less than voltage of less than V F. (750 mV) pulls one -tenth the size of conventional TTL A Look Into the Future. As impres- injector current out of the input or CMOS gates. Even the latest LSI sive as today's I2L devices are, even through the on, or low, output of the forms of TTL gates occupy four times better ones are coming. Right now on driving gate. Thus, deprived of its base as much space as the I2L gate. the way are DVM circuits, high - current, the npn transistor cuts off and frequency counters, digital tuners, the output goes high. This NAND cir- Two Types. Although I2L is a young read -only memories (ROM's), control cuit is converted to NOR logic by wir- technology, two different versions are logic for calculators, touch -control ing the outputs as shown in Fig. 3. already in production. One is the iso- and linear circuits for radio and TV, and circuits for telephone touch - dialing systems. INJECTOR +V Intensive research and development continues to increase the speed of experimental devices. For example, researchers at IBM's Semiconductor Development Laboratories in West Germany are using Schottky -diode clamps on I2L outputs to decrease gate delays. They esti mate that speeds faster than 5 ns will be obtained in the Fig. 4. Simplified diagram shows how 12L is constructed. near future. JANUARY 1976 57

www.americanradiohistory.com J2G]tr 2,&VGiWit ACT5it Shaping tones or ilotes and determining combinations or order. BY DON LANCASTER

ANY electronic music system follow in a given combination or order, eventually end up with a tone whose needs some means for specifying we call it a sequencer. Sequencers frequency and amplitude components the shape and sequence of the tones can operate on fixed rhythm and are specified throughout its duration. or notes produced. The equipment to chording patterns, on random pat- So, where does the initial envelope accomplish this can range from an ex- terns from a composer circuit (as waveform come from and how do we tremely simple keyboard- controlled "teach- and -learn" devices), or as part generate it? on /off manual to elaborate sequential of an elaborate computer system that attack /sustain /decay generators and bases what it will do on a set of com- Envelope Generation. In Fig. 1 are on up to complete digital computer positional guidelines. illustrated some of the things we synthesis sequencing that specifies We have already seen in previous might want to build into a single note everything about the notes and their articles on electronic music that, if we or tone. For the sake of simplicity, as- time order. obtain a waveform that represents the sume that the frequency structure of Any device that shapes the indi- amplitude- versus -time of a desired the tone will remain constant for the vidual notes is called an envelope note, all we must do is route it through tone's duration. (If it does not, simply generator or ASD (attack /sustain/ a keyerorvcato let it modulate either a use more of the same techniques, decay) controller. If some circuitry is basic frequency reference or a com- routing some of the envelope com- determining what tones or notes are to plex tonal structure. Either way, we mands to filters instead of to keyers or vca's.) This leaves us with the basic amplitude shape shown. Now, let us examine the individual parts of our Oberheim Electronics DS -? Digital Sequencer note. ATTACK is the initial rise time of the note. It usually ranges from a few to several hundred milliseconds. Attack waveforms often have a rising exponential, while linear and capacitor charging waveforms are more often used in electronic music since they are much simpler to generate. With the exception of horn blips, the exact changes in the total attack time do not usually have a profound effect on the final tone structure. HORN BLIP is a characteristic single or double implusive "blip" that often appears in a horn voicing, giving it the characteristic "bite" of the trumpet and other brass instruments. It is often obtained electronically by summing a brief impulse wave shape with the normal envelope waveform. PEAK VALUE is the maximum amplitude, often reached at the end of the

POPULAR ELECTRONICS 58

www.americanradiohistory.com PEAK VALUE BODY attack period. Some traditional in- MODULATION HORN strument imitations -particularly the BLIPS SNUBBING English horn -have a two -value attack I I in which much of the initial I amplitude I AFTER I I EFFECTS is rapidly reached. This is followed by I I a much slower rising response to the peak value. FALLBACK is the portion of the waveform from peak level down to TIME - zero or some intermediate level. Many voices -particularly percussion - drop rapidly from a peak to some intermediate level as initial transients I and other high- ATTACK frequency effects b--SUSTAIN DECAY ( -1H rapidly die down. A classic I example of I

I I I this is a bell that gives an initial loud I ---i Fa-- FALLBACK -clang." followed by a long drawn out pure bell tone. Fallback Fig. 1. Envelope of a ¡tote showing various characteristc.s. is essential for most percussion voices, particularly in piano synthesis.

IN914

KEYING WAVEFORM J L TO VCA ATTACK' DECAY (HIGH Z) STARTS¡ STARTS

(A)

SOK J SUSTAIN +5V IN914 ATTACK

TO VCA J ( HIGH I)

GND

(B)

ATTACK IM DURATION IM SUSTAIN

20K ATTACK TO VCA IN914 .01yF IM 10K

( HIGH Z ) 50K IOK

FALLBACK IyF

IM 50K

2.2K +5V

2.2 K IK + 5V -JJAMA --Q +51/ SUSTAIN AMPLITUDE Fig. 2. Al (A) is simple attack /su.stain /fallback /decay circuit controlled by musician. Circuits (B) and (C) pe)forr¡ same function but are controlled by níonostahle oscillators.

JANUARY 1976 59

www.americanradiohistory.com SUSTAIN is the dwell period during your keyer or vca without truncation while circuit (B) performs the same which a note remains at relatively con- or feedthrough. functions but this time is controlled by stant amplitude. It can be very short in SNUBBING is a truncation technique a single monostable oscillator (555). duration or missing altogether in a that is used when you want to pur- By overlapping the attack and decay percussion note. In fact, a percussion posely terminate the decay cycle early. times, we can get a percussion voice can be redefined as a note with a short This snubbing most often crops up with zero sustain. or missing sustain time that is not when you are synthesizing the release Circuit (C) has added to it a second under the immediate control of the of a piano key. A snubbing waveform monostable oscillator to provide musician. If the musician can hold the is usually nothing but a sudden speed- complete control of attack/fallback/ note for a controlled time, we have a ing up of the decay time constant, sustain /decay shaping. All three cir- non -percussion voice. causing a very rapid (but usually a cuits are based on charging a BODY MODULATION is any additional non -zero) decay. capacitor with one resistor that sets amplitude effect that is added to the AFTER EFFECTS can be reverberation, the attack time and a second resistor note during the sustain period. A deep echo, or any of a number of special to discharge the capacitor and set the re- 6- or 7 -Hz tremolo characteristic of effects. They are normally generated decay time. In circuit (C), a second piccolo or flute voice is one possibil- separately with the aid of a reverbera- sistor also discharges the capacitor at ity. Another is the addition of random tion or tape -delay technique. the end of the attack period but shuts noise variations to break up an "exac- If we examine all of the character- off automatically whenever the re- titude" (electronic sound). In tradi- istics wanted in a note, we can see maining capacitor voltage drops tional instruments, this might take the that we need an attack /fallback/ below the sustain amplitude value. form of wind noise, bowing noises, sustain /decay waveform as our basic You can also vary circuit (C) to permit etc. At the other extreme, we could use envelope generation technique. Onto sequential operation of the monosta- all random noise for the body of the this, we can add such things as horn ble oscillators with the first controlling note, as is the case with some percus- blips, noise modulation, snubbing, attack, a second fallback, a third sús- sion effects. As the noise is filtered and echo effects to increase the range tain, a fourth decay, a fifth snubbing, more and more, the greater the degree of total variations at our command. and so on. of filtering, the more it will appear as a pure tone. Hence, with either filtering we can +ISV or randomizing techniques, ENVELOPE a random OUT TO obtain anything from purely KEYING VCA IX 220K hiss to a pure "code practice oscil- MASTER ATTACK lator" tone. The most musical of the (HIGH Z) effects are obviously between these OTHER NOTES IN914 1N914 limits. IM DECAY is the drop -off at the end of IyF -I SV the note. In reality, the decay is almost exponential in form, although +sV always IK higher- frequency components often MASTER DECAY drop off at exponential rates that are OTHER different from those for the lower - NOTES frequency components. Decay times (A) range from a fraction of a second to ATTACK ENVELOPE several seconds and are usually much OUT TO +SV 1N914 VCA longer than the attack times. (This can ULTRASONIC -GNO 47K PULSE -WIDTH (HIGH Z) be reversed in electronic circuits to MODUL ATOR KEYING i yield a "tape played backwards" type OTHER NOTES of effect.) OK IyF Since the decay is the last thing to DECAY +5V occur in a note, and since it is rela- ULTRASONIC in the PULSE -WIDTH tively long duration, obtaining MODUL ATOR IN914 best waveform possible here is very OTHER NOTES important. A true exponential decay (B) (or- better yet -several of them working on different harmonic compo- Fig. 3. Circuit (A) has two master controls for nents) must be used. A linear decay ap- attack and decay; (B) uses ultrasonic pulse -width modulation. proximation will sound unreal. A trun- cated decay will sound even worse. And a decay that does not quite go to Now, let us turn to some simple cir- All three circuits shown in Fig. 2 can zero will produce note feedthrough cuits that will do the job. be only lightly loaded, which means and background noise. Fortunately, that they can be connected to a keyer the normal RC discharge of a Envelope Circuits. Three simple or vca that has a high input imped- more than 3 capacitor is a simple exponential attack /sustain /fallback /decay circuits ance, on the order of decay, although you must be sure the are shown in Fig. 2. Circuit (A) is a megohms. A simple voltage follower, level to which you are discharging simple attack /sustain /decay that is FET follower, or emitter follower cir- represents the zero -amplitude point of under the control of the musician, cuit can be added as required for a

POPULAR ELECTRONICS 60

www.americanradiohistory.com 47K rent +12V through it for one -tenth the +12v 3.9K steady -state current time, and the resistor would appear to have a value IyF of 470,000 ohms. which most conve- OPTIONAL 47K TRIANGLE niently gives us the ability to remotely +12 V OUTPUT Fig. 4. Typical control dozens or even hundreds of OV OUTPUT pulse -width resistors (and the resulting attack and n)odnlator. Two decay times) simultaneously. REVERSE PINS 5 8 6 are heeded for 2307 (EXAR) FOR DECAY DUTY To accomplish the above, we have CYCLE complete control two pulse sources whose duty cycles of all keys. are controlled by potentiometers or 4.7K 4.7K control voltages. These operate at ul- +12V trasonic frequencies, 1000 PF charging and discharging the envelope capacitor in very small steps. The slope of each step is set by the charging or discharging resistor, while the total height IOOK POT 0 -2 MA of FOR CURRENT each step is set by the ratio of the on to MANUAL SOURCE CONTROL FOR the off times the ELECTRONIC of modulator. Since CONTROL each step is a tiny fraction of a decibel in height. and since there are many thousands of them during the evelope lower impedance keyer or gain control (UPWM). It is fully polyphonic, can be generation period, the net result is the circuits. controlled by digital logic or some same as if the capacitor were charged Each of these circuits must have its other easy means, and provides true and discharged. attack and decay times set separately. exponential decay characteristics that A typical pulse -width modulator is The problem now is how to obtain are instantly variable, even from a re- shown in Fig. 4. While the IC costs polyphonic operation so that only one mote location, over a wide range. about $4 (from EXAR Inc., 750 or a very few controls set the overall The trick to this circuit's operation is Palomar Ave.. Sunnyvale. CA 94086), attack for all notes simultaneously, to rapidly switch resistors inside and only two are needed for complete con- while a second group of controls is outside the charging circuit. A trol of all keys, with low -cost diodes assigned to the decay function. Two 47,000 -ohm resistor appears as a doing the actual switching. In this possible approaches are illustrated in 47,000 -ohm resistance when current setup, the attack waveform is routed Fig. 3, one of which is a brand new and is flowing through it. Reduce the cur- through the keyboard's contacts. If very powerful technique. rent to zero, and the resistor behaves this is objectionable, a CMOS logic In circuit (A) is a MASTER ATTACK for like an infinite resistance. Pass cur- gate or analog switch can be substi- all the notes and a MASTER DECAY control that serves all notes in a poly- +3V phonic instrument. Keying charges CURRENT the output capacitor in the positive di- SOURCE ENVELOPE OUT TO rection. increasing the volume VCA of the FILTER vca until a potential slightly greater J v ` than 5 volts is reached. At this point, PERCUSSION NORMAL BANK OF SLIDE POTS the positive clamping diode goes into 00 a 1111111111 conduction and limits the capacitor 4/16 DECODER LOGIC (7415 9) voltage to a maximum amplitude -r (7400) value. Releasing the key discharges CONTINUE GATED +16 COUNTER TYPICAL the capacitor, eventually clamping at OSCILLATOR PROGRAMMING 18288) -r (555) O CARD 0 ground potential at the notes end. BEGIN For long attack and decay times, the charge rate is exponential (actu- DURATION ally one minus the exponential on the (A)

charge cycle and the exponential on ENVELOPE OUT TO VCA the discharge cycle). However, as WRITE DATA OR ROM either the attack or decay times are PROGRAM shortened, the charging rates become SELECTS PERCUSSION more linear. This would be objectional -Y- but for the fact that the linear rates are START CONTINUE associated with the shorter times and Y are thus difficult to notice. Neverthe- less. this is an extremely simple and useful polyphonic circuit. (B) The better technique is shown in Fig. 5. Output of binary counter is shaped by programmed circuit (B). This technique is called ul- pots in (A). I)I (R). pots are replaced by digital memory. trasonic pulse -width modulation

JANUARY 1976 61

www.americanradiohistory.com tuted as the control element, since the signal is really a digital waveform up to DIGITAL DISPLAY (OPTIONAL) the diodes. This technique can easily be extended to include fallback, per- PATTERN and effects. SELECT TO cussion, other AUDIO Purely digital techniques can also be used for generating the envelope, TEMPO but as of now, their added complexity OTÑER limits them to monophonic instru- INSTRUMENTS ments or, at best, to a time -shared or (A) ATTACK priority hierarchy in an instrument. SUSTAIN DECAY Two typical digital circuits are shown ENVELOPE in Fig. 5. PROGRAM PAUSE LOGIC GEN. MATRIX OR SELECTORS In circuit (A), we use an input time NOTE AUDIO reference from a start/stop oscillator GENERATOR ORVKEYER OUT to count out 16 counts of a binary TEMPO PSEUDO TEMPO RANDOM VOICE FILTERS counter. Each count is decoded and OSC. SEQUENCE GENERATOR routed to a slide -type potentiometer.

Using slide pots, you can "draw" the SEQUENCE COMMANDS waveform you want and set the total (S) duration with the frequency of the TEACH time references. You can let the circuit KEEP go completely around for a nonper- TO NOTE "TEACH" RAM OR 'LEARNED' KEVERS cussion voice. Releasing the key then NOTE SHIFT OUTPUT OR SEQUENCE REGISTER SEQUENCE VCA'S MEMORY continues the cycle. So, when you WRITE DATA OUT ADDRESS press a key, you generate the first five IN ADDRESS START levels of the envelope. It then sticks in, STEP COUNTER OR RUN CLOCK 5 for as long as the key is say, position (C) held down. On releasing the key, the note will continue through the decay Fig. 6. Sequencer techniques: (A) has rhythm generator; cycle. As with most envelope (B) generates random patterns; (C) is teachltear n device. schemes, some type of memory, usually a sample -hold or a digital latch, is essential if the key's frequency is to be remembered after the key is released. select any of a number of fixed en- dom tone patterns. These patterns are The main advantage of the slide -pot velopes. combined with program selectors and scheme is its extreme versatility, pause selectors to generate hundreds especially since you can generate all Sequencers. Three popular se- of thousands of tonal sequences, and manner of envelope shapes that are quencer techniques are shown in Fig. at around $50 cost much less than unreal or extremely difficult to gener- 6. A sequencer governs the order and most synthesizers. One such ate with a traditional instrument. combinations the notes follow, rather random -pattern generator was the These include echo, multiple bursts, than the shape of each individual note. "Psychtone I" that appeared in this reverse attack, etc. One limitation of Technique (A) has a rhythm generator magazine as a construction article in this scheme is that you really should or sideman. An early version of these February 1971 and is still available in use more than 32 slide pots, and circuits appeared in POPULAR ELEC- kit form from Southwest Technical another is that the tolerance of the TRONICS as the "Drummer Boy" (July Products Corp., 219 West Rhapsody, pots can be rather restrictive as you 1971). Today, you can do the whole San Antonio, TX 78216. are setting each slider to a slightly dif- thing with a single S8890 IC from Circuit (C) in Fig. 6, a variation of ferent value from its neighbor. American Microsystems, Inc. (3800 circuit (B) in Fig. 5, is a teach /learn se- Programming the circuit is quickly Homestead Rd., Santa Clara, CA quencer. A commercial version called accomplished with a plastic program 95051) or the M250 IC from SGS -ATES the Model DS -2 is available from card, first homing the sliders and then (435 Newtonville Ave., Newtonville, Oberheim Electronics (1549 Ninth St., using the card to set them to the de- MA 02160). The IC's are available at Santa Monica, CA 90401). Teach /learn sired values. Once your favorite en- about $25 in unit quantities. Both IC's devices of this type can employ either velopes are chosen, you can install generate the combination rhythm pat- RAM's or shift-register memories. One fixed resistor matrices that can be terns for rhythm accompaniment and good choice for experimenters would switched into the circuit in place of the are available in a standard pattern be the Signetics hex 32- and hex 40 -bit pots in either preset or stop fashion. (traditional rhythms) as well as in cus- shift registers (2518 and 2519), par- Circuit (B) replaces the analog slide tom patterns at much higher cost. ticularly since they are beginning to pots with a purely digital memory. For Electrically, the IC's operate in much appear on the so- called "surplus" initial setups and experiments, you the same manner as circuit (B) in market for as little as 25¢ each. Brand can use a read /write or random - Fig. 5. new IC's directly from the factory are access memory (RAM). For perform- Circuit (B) in Fig. 6 is a composer/ currently selling for less than $5 and ance and concert use, a read -only synthesizer that employs a pseudo- form the basis for many teach /learn memory (ROM) can be used to rapidly random sequencer to generate ran- music experiments.

62 POPULAR ELECTRONICS

www.americanradiohistory.com Triplett 310 miniVOM's fit your hand and your wallet...

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The high quality Triplett 310 is a'ittle all -in -one VOM. This made in the U.S.A. VOM gets around a lot for half fare. It packs most of the features you'd expect to find only on a meter twice the size and price. It fits in your shirtpocket easily. The small size and its versatility is a boon to field servicemen as well as circuit designers, technicians, electrical maintenance eng neers, and the price is right for vocational and hobbyist use. A newly designed high impact, c1,-op resistant case makes it practically indestructible ... 20K ohms /volt DC and 5K ohms /volt AC ranges provide plenty of seisitivity for most applications ... and, there's diode overload pro:ectior with a fused R X 1 ohm range. The single range selector switich is a -eal time saver for reading 0 - 1200 DC or AC volts, 0 - 20 megohms, and 0 - 600 micro -amps or 0 - 600 milliamps at 250 millivolts. Comes complete with 42'` leads, alligator clips, batteries and instruction manual. Accessories tr ple the versatility of a 310. Adding the Model 10 clamp -on ammetar allows you to measure AC currents easily with one hand. Visit your local distributor or Mod Center and shake hands with a real bargain.

THE MARK OF 1TF TRIPLETT QUALITY BLUFFTON, OHIO 45817

Triplett. T e readers C CLE N Oasy

www.americanradiohistory.com From CIE - Cleveland Institute of Electronics learn by doing! Perform more than 200 exciting experiments with CIE's fascinating ELECTRONICS LABORATORY PROGRAM!

POPULAR ELECTRONICS

www.americanradiohistory.com You get your own Experimental Electronics Laboratory... work with components comparable to those used by industry!

With CIE's Experimental Electronics Labora- Testing and troubleshooting are an important Modern space -age components like this IC tory, you'll perform actual experiments and part of your learning experience. Included in (integrated circuit) are professional quality become adept at handling components. This your laboratory is a precision "multimeter" and can be used again and again in many of valuable "hands on" experience helps you to diagnose electrical and electronic troubles your projects. Lesson by lesson, piece by learn the "how" as well as the "why." quickly and accurately. piece your knowledge grows! Prepare now for a rewarding career in Electronics ... the Sc fence of the Seventies.

Electronics miracles are changing to- To get an FCC License, you must pass skills and knowledge in demand. Com- day's world with breathtaking speed. a licensing exam administered by the puters and data processing. Air traffic This growth in electronics technology government. And we are confident you control. Medical technology. Pollution has generated a need for electronics can successfully earn your license, if control. Broadcasting and communica- technicians trained in theory and practice you're willing to put forth an effort, be- tions. Once you have the solid technical to build the products, maintain them, and cause the vast majority of CIE students background you need, you can go after troubleshoot them during the Seventies have. In fact, based on continuing sur- the career field you want ... work for a and beyond. veys, close to 9 out of 10 CIE graduates big corporation, a small company, or Don't just wait for something to "hap- passed their FCC exams! even go into business for yourself. pen" in your present job. Get ready now That's why we can offer this Warranty: Yes, Electronics can be the door to a for a career you'll really enjoy ... with when you successfully complete any CIE whole new world of career opportunities the opportunity for a good income and career course which includes FCC Li- for you. And CIE training can be your key. the chance for advancement. cense preparation, you will be able to pass the Government FCC Examination Send for FREE school catalog Practical experience with Discover the experiments for the License for which the course pre- opportunities open to peo- "Hands on" experience helps to rein- ple with electronics training. Learn how pared you or you will be entitled to a full CIE career courses can help you force basic theory. When you learn by refund of an amount equal to the cash build doing, you discover the as well as new skills and knowledge and prepare "how" price of tuition for CIE's Course No. 3, the "why." You'll find out for yourself the you for a meaningful, rewarding career. "First Class FCC License," in effect at right way as well as the wrong way to use We have courses for the beginner, the the time you enrolled. This warranty is for electronic components. How to construct hobbyist, for the electronics technician, good from the date you enroll until the your own circuits, to discover trouble and for the electronics engineer. last date allowed for completion of your Whether spots and learn how to fix them. course. you are just starting out in Electronics or CIE offers a number of are a trained in laboratory That's it! We warrant that you will get college- engineer need of courses where you learn Electronics by the License you trained for. updating (or anywhere in between), CIE "doing it yourself." You work with your has a course designed to fit your back- own hands on electronics components You'll have attractive ground, experience, and future goals. and lab equipment. This combination of job opportunities Send today for our FREE school cata- "head and hands" learning locks in your There have already been many exciting log and complete career information. For understanding of the crucial principles developments and breakthroughs in Elec- your convenience, we will try to have a you'll use on the job in your new career. tronics and some people might assume representative call to assist in course And you do it all at home, in your spare there will be no new frontiers ... no new selection. Mail reply card or coupon to time, at your best study pace. CIE's out- worlds to conquer. Not so. CIE . . . or write: Cleveland Institute of standing lessons allow you to progress Electronics is still growing. In nearly Electronics, Inc., 1776 East 17th Street, step by step. An instructional technique every one of the new and exciting fields Cleveland, Ohio 44114. Do it TODAY. time -tested for over 40 years of special- of the Seventies you find electronics ized electronics independent home -study training. -1 Cleveland Institute of Electronics, Inc. sry>41..tif Importance of an FCC License CIE 1776 East 17th Street. Cleveland, Ohio 44114 and our Warranty Accredited Member National Home Study Council If you want to work in commercial broad- Approved casting ... television or AM or FM broad- Under Please send me your FREE school catalog and career information package. casting ... as a broadcast engineer, I am especially interested in: federal law requires you to have a First G.I. Bill Electronics Technician Industrial Class Radiotelephone License. Or if you Electronics plan to operate or to maintain mobile All CIE career FCC License Preparation Electronics Engineering two -way communications systems, micro- courses are ap- Color TV Maintenance Other wave relay stations or radar and signal- proved for edu- Mobile Communications ing devices, a Second Class FCC License cational benefits is required. under the G.I. Print Name Even if you aren't planning a career Bill. If you are a which involves radio transmission of any veteran or in ser- kind, an FCC License is valuable to have vice now, check Address Apt. as Government certification of certain box for G.I. Bill technical skills. It's a job credential rec- information. City State Zip ognized by some employers as evidence Check box for G.I. Bill information. p Veteran On Active Duty PE 9 that you really know your stuff.

CIRCLE NO 12 ON FREE INFORMATION CARD JANUARY 1976 67

www.americanradiohistory.com dle. Unlike other record changers, this player does not depend on the automatic spindle to lift or support the Product record stack while a record is being dropped to the turntable. A post just outside the rim of the record helps do Test Reports the supporting. The spindle contains only a slim rod that pushes the bottom record off the ledge of the support. Only a slight force is required for this action, well within the capabilities of the belt -drive system. ABOUT THIS MONTH'S HI -FI REPORTS The tubular tonearm is mounted on needle- bearing gimbal pivots, with a The British Industries Co. Model 980 Multiple Play Manual Record rotating elastically mounted counter- Player is, to our knowledge, the first successful adaptation of a belt drive to weight. A scale on one of the gimbal an automatic record changer. This electronically controlled player of- rings is calibrated from 0 to 4 grams at fers almost every design and operating feature one could desire, plus a high 0.25 -gram intervals for setting stylus level of performance, at a reasonable price. tracking force. Separate levers are Pickering's PP -1 preamplifier equalizes and amplifies the output of a provided for setting the tracking force magnetic cartridge, delivering a signal suitable for the high -level input of and antiskating compensation. Nor- any amplifier or receiver. It makes it possible to use a second record player mally set to coincide, both levers can with amplifiers not equipped with two magnetic- cartridge inputs, as well as be moved in a single operation. If de- up- dating an older amplifier which was originally designed for use with sired, however, they can be set sepa- ceramic cartridges. rately. - Julian D. Hirsch Unlike other cartridge shells with which we are familiar, this one does not plug or slide into the tonearm. A four -pin plug on its side mates with a BIC MODEL 980 MULTIPLE PLAY MANUAL RECORD PLAYER connector on the tonearm, with a Automat %(' turntable with belt drive. single nut locking it into place. A screwdriver adjustment tilts the entire shell for the correct vertical tracking angle. (A plastic jig is supplied for setting the correct stylus overhang for minimum stylus tracking error.) At the end of the shell is a small sliding lever that is used for setting the vertical angle for single or multiple play. For multiple play, the angle is set for the center of a maximum six -disc stack. The record player's operating controls are grouped on a panel along the right side of the motorboard. At the rear is a lever that is used for modify- ing the antiskating compensation for conical and elliptical styli. Next is the cueing lever that operates the cueing At the top of the wh ich puts the rumble frequencies at system whose action is damped in ciHIRSCH- British Industries a very audible 30 Hz. both directions. A small knob near the HOUCK Co. line of "Pro- Mounted in its walnut base, with base of the tonearm lets the user ad- grammed Multi- dust cover in place, the record player just the damping for a descent of from ple Play Manual measures 17 1/16 "W x 14 11/16 "D x one to three seconds. The speed - Turntables" is the Model 980. It may 7 "H (43 x 37 x 18 cm). The basic turn- select control is a slide lever. well be the first belt- driven automatic table retails for $199.95, while an op- A slide -type "programming" lever changer. tional walnut base and dust cover are comes next. Because this record The turntable's 12" (30.5 -cm) non- priced at $16.95 and $9.95 respec- changer does not employ the center ferrous platter is belt- driven to operate tively. spindle to sense the presence or ab- at either 33 1/3 or 45 rpm by a 24 -pole sence of records to control the au- synchronous motor. This low -speed General Description. For single - tomatic changing mechanism, it must motor, operating at 300 rpm (which play operation, a short spindle that ro- be preprogrammed for the number of corresponds to 5 Hz), places most of tates with the record goes into the discs in a stack or for the number of the rumble frequencies below the au- center of the platter. When operating times a single disc is to be played. The dible range. In contrast, the usual in the multi -play mode, this spindle is control has positions for OFF, MAN, and four -pole motor revolves at 1800 rpm, replaced with a taller automatic spin- i through 6, the last for the number of 68 POPULAR ELECTRONICS

www.americanradiohistory.com discs in the stack or the number of Laboratory Measurements. For from +4.3% to 2.9% at 33 1/3 rpm times a single disc is to be played. The our tests, we inserted a good -quality and from +3.8% to 3.4% at 45 rpm. final control is labelled CYCLE. phono cartridge into the player's There was a very slight drift in speed The player's motor drive and control tonearm shell. The tonearm reso- during the first half hour or so of oper- system employs a stable oscillator that nance was at 8 Hz at about a 7 -dB ation, which was barely detectable on generates a 60 -Hz drive that is inde- amplitude, which is an indication that the stroboscope. pendent of power -line frequency and the tonearm's mass is compatible with The unweighted rms wow and flut- voltage. A small knob at the left front the majority of today's high - ter were each 0.03% to 0.04% at both of the system's base permits the compliance cartridges. speeds. The unweighted rumble was platter's speed to be trimmed by ±3 %. The calibrations on the tracking 32 dB, essentially in -the horizontal Stroboscope markings under the plat- force dial were exact, within the plane. The ARLL audibility weighting ter can be viewed through a window 0.05 -gram resolution of our force yielded a very good 61 -dB figure. The on the motorboard. There are sepa- gauge, and the force did not change change cycle in automatic operation rate markings for 50- and 60 -Hz by any detectable amount from the required 12 seconds, which is about power -line feeds and for both operat- first to the last disc in our 1/2" high average for record changers. ing speeds. stack. The tracking error of the tone - In the single -play mode, a disc is arm was as low as we have ever meas- User Comment. The problems that a placed on the platter with the short ured on a pivoted tonearm of compar- pure belt- driven system presented to spindle, the programming control is able dimensions. Between radii of 2.5" designers of record changers in the set to position i, which starts the plat- (6.35 cm) and 6" (15.84 cm), the max- past have obviously been overcome in ter rotating, and the CYCLE button is i mum error was less than 0.3 ° /in. At the this model. As a result, its wow, flutter, lightly touched. The pickup automati- inner radius, it was essentially zero. and rumble specifications are as- cally indexes for a 12" diameter when The tonearm and cable wiring capaci- tonishingly good for a changer, being the speed selected is 33 1/3 rpm or for tance was 120 pF, which is slightly in a class with many of the fine 7" diameter when the speed is 45 rpm. higher than desirable, but usable with single -play turntables. After the disc has been played, the CD -4 cartridges. Operating the changer is different in tonearm automatically returns to its Similar to most antiskating systems at least one respect from others we rest post and the player shuts off. For we have used, this player's system had have examined, however. For exam- straight manual operation, or if a non- to be set about 1 gram higher than the ple, lacking a spindle sensor to control standard combination of record tracking force for optimum compen- the changing mechanism, one must size /speed is involved, the program- sation. This is not a critical adjust- count the number of discs in a stack mer control is set to MAN, which starts ment, and for most purposes the indi- and "program" the player. Also, for the platter rotating, and the tonearm is cated settings should prove satisfac- those who like to switch cartridges for, positioned by hand. The only automat- tory. The cueing system operated say, playing records singly or automatic operations in the manual mode are smoothly, with no outward drift during ically, there's a mechanical hassle in- tonearm return and system shutoff. tonearm descent. The rate of descent volved in the use of a tiny securing nut. For multiple -play operation, the au- was adjustable over a range from 2.5 Other, more expensive changers tomatic spindle is inserted and a stack to 4 seconds. have special features that justify their of up to six discs is loaded onto it and The operating speeds were exact prices, but in basic performance the side support post. The program- when the stroboscope pattern was parameters -the ones that affect what mer is set to the number of discs stationary. They did not vary by any you hear -the Model 980 takes a back loaded, and the CYCLE button is appreciable amount when the line seat to none. Equally important, this pressed. This button, incidentally, re- voltage was changed over a performance is obtainable at a mod- quires only 90 grams of operating 100 -to- 135 -volt range. At 95 volts, the erate cost. force and a travel of just 1/16" (1.6 mil- speed slowed by an insignificant 0.3 %.

limeters). The vernier (speed -trim) range was CIRCLE NO. 80 ON FREE INFORMATION CARD

PICKERING MODEL PP-1 PHONO PREAMPLIFIER needed for a magnetic cartridge. In Updates low -cost music systems for use of magnetic cartridge. most cases, however, the tonearm of the record changer will accommodate a standard magnetic cartridge with 'h -in. (12.7 -mm) centers. The preamp The Pickering can also be used to connect a second KIRSCH- Model PP -1 record player to an amplifier equipped HOME phono preampli- for only one magnetic- cartridge input. fier is designed for use in up- General Description. The self - grading low -cost music systems by powered preamp measures 43/8"D x permitting the replacement of ceramic 31/2 "W x 2 "H (11.1 x 8.9 x 5.1 cm). Its cartridges with magnetic units. The two input jacks accept the signal ca- type of record player equipped with a bles from the record player's car- ceramic cartridge, of course, does not tridge, while a pair of shielded cables have the equalizing preamplifier (not furnished) go from the preamp's

JANUARY 1976 69

www.americanradiohistory.com weighting, corresponding to the sub- jective effect of the noise, the S/N was an impressive 77 dB, with or without ii11Ói1 íi %11i1i the filter. The distortion was too low to iQi1l111111 be measured accurately at most usa- ll:1hit1 PICKERING ble output levels, being submerged in PP-I !

é RUMBLE : FILTER RIAA EQUALIZATION ERROR i the low hum and noise output. At 2 11 1111EM volts output, the 1000 -Hz THD was an 11111111111111111111 11i11=11111111=111,111 insignificant 0.05 percent. 1.000 20000 FREQUENCY Hz) The RIAA equalization was better _ than ±1 dB from 20 Hz to 20,000 Hz. The rumble filter began to roll off the output jacks to the Aux inputs of an magnetic pickup. The filter is rated to response below 300 Hz, with the amplifier. Because no power switch is provide at least 15 dB attenuation of -3 -dB point at 170 Hz. It reached a provided on the preamp, the line cord rumble frequencies. maximum attenuation of 10 dB at fre- should be plugged into a switched The retail price of the Pickering quencies below 40 Hz. Unlike many convenience outlet on the amplifier. Model PP -1 preamp is $29.95. phono preamps, the equalization of The specifications of the preamp the PP -1 was virtually unaffected by are limited to the fundamental charac- Laboratory Measurements. With the inductance of the phono cartridge. teristics of a phono preamp. The input a 10 -mV input producing a 1 -volt out- Whatever the cartridge extracts from impedance of 47,000 ohms matches put, the measured 1000 -Hz gain of the the disc will be passed on intact to the all current stereo cartridges. The gain preamp was 40 dB. The maximum un- amplifier. at 1000 Hz is 38 dB, and the RIAA distorted output was 2.5 volts, which equalization is rated to be within -_t-2 suggest the advisability of using rela- User Comment. We found that the dB of the ideal characteristic from 30 tively low- output magnetic cartridges preamp does a fine job in its intended Hz to 15,000 Hz. The S/N is stated as (ones with, say, no more than a 5 -mV application. We connected the being at least 60 dB, and crosstalk be- output level) to minimize distortion preamp to the AUX inputs of our regu- tween channels at better than 60 dB from preamplifier overload on loud lar hi -fi amplifier and used an Ortofon down. recorded passages. Model M15E cartridge (quite a bit A rumble filter is included in the The crosstalk at 1000 Hz was -64 higher in quality than would normally preamp in the expectation that many dB. The S/N ratio, referred to 1 volt be used in such a conversion) for our systems in which it will be used will output, was a good 69 dB (unweight- listening test. The results were first have inexpensive record changers ed). It improved to 72 dB when the rate, sonically indistinguishable from whose relatively high rumble cannot rumble filter was switched in, which the performance of the cartridge be reproduced by a ceramic cartridge reduced the small amount of power - through the usual PHONO inputs. but might prove troublesome with a line hum in the output. With IEC "A" CIRCLE NO. 81 ON FREE INFORMATION CARD

TRAM XL AM CB TRANSCEIVER reverse Mobile rig has excellent noise limiting modulation -polarity protection, and line und control. filter. The transceiver retails for $159.95.

The Receiver. An unusual aspect of the double- conversion receiver used is the absence of an r -f input amplifier preceding the first mixer. However, good sensitivity is still obtainable, as indicated by our measurement of 0.55 µV for 10 dB (S +N) /N at 30% modulation with a 1000 -Hz test tone. This is close to the average generally achieved with receivers that are equipped with an r -f amplifier. Without the amplifier, chances of signal over- The Tram XL mobile AM CB trans- and an unusually good automatic loading are minimized. The result is ceiver measures a compact modulation control (amc) system are that the XL's receiver section has bet- 6.3 "Dx 5.5 "W x2 "H(16x 14x5cm), its attributes. ter signal -handling ability than is usu- yet delivers "big" performance on all Other features are: adjustable ally the case. Good image rejection, 23 channels using crystal -controlled squelch, PA operation, built -in measured at 62 dB, is achieved by two frequency synthesis. Good receiver speaker, external- speaker jacks, mi- loosely coupled tuned circuits at the sensitivity and selectivity, excellent crophone, theft -deterrent mobile input and the transmitter antenna automatic noise limiting (anl), an mounting hardware, 12 -volt positive - matching network. Protective diodes easy -to -read meter, operation at full or negative -ground power system, are provided in the receiver's input. legal power with clean modulation, zener -diode voltage regulation, The intermediate frequencies are 70 POPULAR ELECTRONICS

www.americanradiohistory.com ALLISON

7.8 MHz and 455 kHz. A 7.8 -MHz band - measured 4 watts when the trans- OPTO- ELECTRIC ' pass circuit between the two mixers ceiver was powered up from a The BEST...the ULTIMATE aids unwanted signal rejection, which 13.8 -volt supply. of ALL Ignition Systems! measured 60 dB over most of the The audio section of the receiver, range. As often occurs in this type of used for modulating the collectors of We challenge ANYONE to dispute this Fact) conversion and synthesis, a spurious the driver and power amplifier stages, response can be produced by a signal is preceded by a speech amplifier that near 30 MHz. The rejection factor for is automatically switched in when the this "image" was 36 dB. Rejection of rig is on transmit. the 7.8 -MHz i -f in the 455 -kHz stage The amc in this transmitter differs was 60 dB. from the usual compression system. Never wears out or needs any Maintenance! Selectivity is obtained through the The collector and emitter leads of a use of a ceramic filter. Adjacent - transistor are connected across the w channel rejection was nominally 53 speech amplifier's input. A dc control gives you Maximum Power dB, and the overall response, includ- voltage, obtained by sampling the with continuous PEAK PERFORMANCE ing that of the receiver's audio sec- modulating voltage through a ...while reducing Maintenance tion, was 350 to 3300 Hz. voltage -doubler system, is applied to and Operating Costs! A single diode is used for detection the transistor's base. When the mod- * The Allison OPTO- ELECTRIC System eliminates the Points and Condenser, replacing them with an OPTO-ELECTRONIC and agc. The agc, applied to the two ulating voltage rises above the level TRIGGER, using a Light- Emitting Diode and Photo transistor. mixers, held the audio output to within required for 100% modulation, the re- The System operates on a beam of Light. As there are NO moving parts in rubbing contact. "Friction -wear' is completely 7 dB with a 20-dB r -f input change at 1 sulting dc control voltage reduces the eliminated_ Timing adjustments are PERMANENT. to 10 pV and to 12 dB with a 60 -dB collector- emitter resistance of the Gives 40 -Times more Timing accuracy than ANY system using "Mechanical" Breaker -Points! UNLIMITED RPM! input change at 10 to 10,000 pV. transistor, causing it to reduce the "Electronically- Controlled" DWELL automatically supplies HIGHEST Performance at both Low and High speeds. Spark The meter does double duty as a speech input level. It thus acts as an strength does not fall off at high RPM. POSITIVE SPARK signal- strength and transmitter - automatic volume control that com- helps eliminate "Misfire' for faster acceleration and improved Engine Performance Sparkplugs LAST 3 to 10 -Times LONGER. output indicator. Readings of about pensates for excessive speech levels Easier Starting under any condition! Smoother running... S9 were obtained with input signals of as needed to prevent overmodulation. (NO TIMING FLUCTUATION as with Magnetic Impulse Units) The is All SOLID-STATE Components. UNAFFECTED By Temperature, 50 to 100 pV. The thermistor- stabilized result extraordinarily good amc Moisture, or Vibration! Only Highest grade materials used squelch was adjustable for thresholds performance. Guarantees you Solid, Dependable Performance! of 0.35 to 550 pV. Raising the microphone input level PERFECT TIMING INCREASES Engine Efficiency and Gas Mileage. SAVES Precious Fuel! Allison gives you MAXIMUM

A series -gate and follows the detec- 20 dB above that required to produce Engine Efficiency 100% of the Time . and that's the name of tor. The audio section of the receiver 100% modulation maintained a clean the game for the BEST in GAS MILEAGE AND ECONOMY. Perfect Timing and Dwell never change. consists of three stages that end with a sine wave at full modulation, without * Pays for itself! Eliminates ignition Tune -Ups forever! class -B amplifier stage, which pro- clipping or negative -peak crossover. "INFINITE LIFE "...Once installed. Never needs replacing! vided a measured output of 3 watts at Under these conditions (20 dB com- 6% distortion into an 8 -ohm load using pression), the distortion with a * PROVEN RELIABILITY! Each Unit Tested to 15,000 RPM. a 1000 -Hz test tone. 1000 -Hz test tone was only 5% and Road and Race Proven. adjacent -channel splatter was down (Opto- Electric Systems won at INDY Two years in a row!) The Frequency Synthesizer. A 55 dB. With a 2500 -Hz tone, it was 40 aa. conventional frequency- synthesis dB down, and with voice modulation, You CAN install the ALLISON System in ALL Foreign system is employed in the transceiver. it was 60 dB down. Using a 400 -Hz the U.S. made & Cars! (4, 6. or 8-Cylinder) It 10 six of which are utilizes crystals, tone, most CB transceivers have high "EASIEST -TO- INSTALL" UNIT ON THE MARKET. in the 11.8 -MHz region and the re- distortion products, but with the XL, Not necessary to dismantle Distributor as with other systems) mainder in the 7.5 -MHz region. Pairs 20 the even with dB of compression, * If you want the BEST, SAVE! This is IT! of crystals are used to create the local distortion was only 8.5 %. ORDER with CONFIDENCE... 54995 oscillator signal at the first mixer to Referred to 1000 Hz, the audio re- SATISFACTION GUARANTEED Only or Full Refund COMPLETE. generate the 7.8 -MHz i -f when com- sponse was 475 to 5000 Hz at the 6 -dB 10-YEAR FACTORY WARRANTY! bined with a given CB channel signal. points. A 2 -dB rise occurred at about )Free Repair or Replacement) that s EVERYTHING' including A 7.345 -MHz crystal is used for 2000 Hz. The frequency tolerance of Postage Insurance Send Check or Mi 0 S heterodyning at the second mixer to the transmitter was within ±150 Hz at State Make. Year. Engine Size. (calir. Res add Tax) (So New...it's Sold ONLY FROM FACTORY DIRECT). produce the second i -f. 80° F (27.3° C). * You may use your MASTER CHARGE or BANKAMERICARD. is Send us (1) Your Number, (2) Interbank No , (3) Exp Date The Transmitter. On transmit, the User Comment. The transceiver aaa synthesizer's output is combined with built into a tough Cycolac plastic case. * Before buying any other Type ignition system a 7.8 -MHz crystal -controlled signal to Miniature slide switches are provided Send Postcard for our FREE BROCHURE. produce the on- channel carrier. The for CB /PA mode selection and activat- It you have already installed a C -D ignition system. Increase its Efficiency... is re- ing and deactivating the anl. The Modernize and carrier filtered against spurious CONVERT YOUR "C -D" UNIT TO BREAKERLESS! sponses by a triple -tuned bandpass channel selector knob is easy to grip. Opto- Electric "TRIGGER UNIT "...Only '34.95 aaa circuit. The rest of the transmitter Aside from having white position indi- Our BEST Salesmen are the users of our ALLISON System! aaa a r -f the VOLUME and SQUELCH con- consists of conventional ampli- cators, America's Oldest and Largest Mfg. of fier, driver, and power amplifier sys- trols also have tabs that let the user Opto- Electronic Ignition Systems. tem. A multi- section pi network "feel" as well as see their positions. minimizes harmonics and matches Although the edgewise meter move- +`c''orrrs ALLISON co AUTOMOTIVE COMPANY the output to 50 -ohm transmission - ment isn't large, it's well -illuminated 1267. P, East EDNA PL., COVINA, CAL. 91722 line /antenna systems. The r -f output and has a pointer that's easy to see. CIRCLE NO 3 ON FREE INFORMATION CARD JANUARY 1976 71

www.americanradiohistory.com The speaker is mounted facing up, amc system to deliver a clean, fully - noise -blanker /anl systems. At least which can present a problem for modulated signal without splatter 60 -dB attenuation of high impulse - under -the -dash mounting. However, over a wide range of voice levels noise peaks was measured with no an external speaker can be used. -even when we shouted directly into noticeable vehicle ignition noise and The fine performance of the trans- the microphone. only a non -interfering trace during ceiver is evident from our test results. The effectiveness of the and was weak -signal conditions.

We especially liked the ability of the equal to or better than that of many CIRCLE N0. 82 ON FREE INFORMATION CARD

HEATHKIT MODEL TD -1006 4- CHANNEL COLOR ORGAN KIT when the system is driven by a wide - spectrum The lamps New apprnnclc prof ic/e.e rtni,muril signal. are ar- ranged in a star -burst pattern whose radials alternate in color. The display's a separate rectififer circuit to an SCR density is greatest at its center, where that, in turn, drives the channel's re- a single circle of red lamps is located. *' spective colored light string. Red The center is the only circle that has a lights are used in the lowest - single color. All outer circles have two * eA frequency channel, followed by blue, or more colors of lamps. ** # t green, and amber lamps as the fre- s . # quency goes up. Assembling the Kit. Assembly of + ! * The drive signal for the color organ the matte -black display board con- is taken from across the speaker ter- sists of mounting eight wood blocks minals or the speaker output of an and the hardware for securing the amplifier or receiver. The system's power supply and main pc board as- 5000 -ohm input impedance is de- Then a semblies. the strings of lamps signed to have only a minimal loading are plugged into the hole matrix. The effect on the driving amplifier. To ob- lamps must be individually removed tain the full 25 -dB dynamic range from from their bases during installation the color organ, an input signal level and replaced immediately thereafter. range of 1 to 28 volts is required. Since these are series -string lights, Though the popularity of the col- The color organ has its own built -in each must be checked out before pro- or organ declined somewhat a power supply. The colored lamps con- ceeding to the next string. (If one lamp few years ago, it is back again in a form sist of strings of miniature Christmas in a string is burnt out or not making that promises to put it at the top of the tree lights that require up to 117 volts contact, none of the lamps in the audio -visual field once more. The of drive potential, which is controlled string will come on.) Heath kit Model TD -1006 takes a sharp by the SCR's. Next comes the gluing of the black departure from the display format that There is only one external control fabric to the clear plastic sheet. Since was adopted by manufacturers a on the color organ. This is the power the fabric must be stretched during number of years ago. Instead of ran- on /off switch that is ganged with the this procedure, the task might have domly positioning a number of col- SENSITIVITY control. Inside the cabinet, proved difficult. However, Heath ored lamps, the TD -1006 employs a on the main printed circuit board as- thoughtfully provides not only the balanced geometric pattern that sembly, are eight more trimmer con- glue for the job, but the clamps to hold seems to pulsate, explode in a trols, two assigned to each channel the fabric taut as well. fireworks display, and pinwheel as the (string of colored lights). Mounting the components on the music goes through the octaves and Externally, the color organ resem- two printed circuit boards takes up the runs through a wide decibel range. bles a flat, square speaker system. Its next portion of the assembly proce- For want of a better descriptive, the front panel, behind which is located dure. Neither board is crowded, which Model TD -1006 is a "picture" color the display board, is covered with a greatly simplifies wiring. This done, organ. Four channels of colored lights black fine -mesh fabric. Directly be- the rest of the work is mainly mechan- and their driving circuitry are housed hind the fabric is a lensed clear plastic ical. All told, it took us some six hours in a walnut -grained vinyl -clad cabinet sheet. The lamps are set into clear to assemble the kit, working from the that measures 223/4" square only plastic "flower buds" that spread the well -written and excellently illustrated 41/2 "D (57.8 x 57.8 x 11.4 cm) and point- source illumination out into a assembly manual. weighs 18 pounds (8.2 kg). The system star -like pattern. Tiny lenses in the After allowing the color organ to can be hung on a wall or stood on the clear plastic sheet and the mesh fabric "burn in" for the recommended floor or on a shelf. Retail price of the have a further effect on the dispersion period of time, we proceeded to the kit is $79.95. of the light from the individual lamps. adjustment steps. Less than a half (The fabric also prevents the back - hour later, we were ready to put the General Description. The color scatter of the light from within the color organ into our music system. organ is built around a conventional color organ and limits the amount of amplifying system whose output goes ambient room lighting that can enter User Comment. Although we had to four bandpass filters. The center the display.) gone through the fad era of the color frequencies of the filters are roughly There are 35 of each color lamps in organ and had been sated the way so 80, 350, 1000, and 3000 Hz. Each the color organ's display, adding up to many other people were, we were bandpass filter's output goes through a total of 140 point sources of light pleasantly surprised when we first 72 POPULAR ELECTRONICS

www.americanradiohistory.com turned on the new Heath color organ Tomita's syntesizer arrangement of and played some music while watch- "Pictures at an Exhibition" (RCA), ing the display. After living with it for which has a number of special pas- several months, we find this color sages that appear to bring out the organ's effect as refreshing as it was color organ's full effects. the day we first turned it on. Viewing conditions are best max- One must see the TD -1006 perform imized when room lighting is low and to really appreciate it. As the frequen- not aimed directly at the display. Also, cies in the music change and the the best effect is achieved when the signal level rises and falls, the star- display is viewed head -on; the further burst pattern of lights explodes, pin- off -axis you get, the more blurred the wheels, pulse -beats and throbs, ex- display becomes. (This isn't surpris- pands outward and folds back on it- ing, considering the double lensing self. Transients are captured in a system used.) nova -like display, and when all the Most amplifiers and receivers capa- lights are on and flickering with the ble of developing a few watts of output rise and fall in signal level, there is a power (assuming a signal level of jewel effect. some 15 or more volts) will drive the While the color organ responds to color organ. One type of receiver that all types of music, it appears to have shouldn't be used is AM. Since the an affinity for the pure tones of the color organ uses SCR's to control the synthesizer whose psycho -visual ef- lamp strings, every time the SCR's go This protects fects can be "mind blowing." With through zero crossing they generate classical and most modern (not rock) noise that can be picked up by the your most music, the effect is highly appealing. standard AM receiver. expensive So far, our favorite selection is CIRCLE NO. 90 ON FREE INFORMATION CARD hi -fi investment. SENCORE MODEL CR31 CRT TESTER & RESTORER Versatile, easy -to -use TV service instrument. Trying to economize by putting off the replacement of a worn stylus could be like throwing away five dollars every time you play a record. Since the stylus is the single point of contact between the record and the balance of the system, it is the most critical component for faithfully reproducing sound and protecting your record investment. A worn stylus could damage your record collection. Insure against this, easily and inexpensively, by having your dealer check your Shure stylus regularly. When required, replace it immediately with a genuine Shure replacement stylus. It will bring the entire cartridge back to original specification performance.

Shure Brothers Inc. TV PICTURE tube testers and General Description. The inside 222 Hartrey Ave., Evanston, IL 60204 restorers are among the most cover of the CR31 contains 15 CRT In Canada: A. C. Simmonds & Sons Limited valuable instruments a TV service plug -in sockets that enable one to e technician can own -whether he is a make tests on virtually any CRT, color SHURE full -time shop owner or a part- tirner. or black- and -white, including the RCA The expenditure for such an instru- 110 °, 17" Trinitron and GE's Quad - ment can be quickly recovered, and its line. There is also mounting space for profit- making potential is great. a handful of extra sockets, which will Furthermore, the service technician be made available by the manufac- can operate in a more professional turer when new CRT's are released. manner when he uses a CRT The electronic portion of the in- 1976 & tester /restorer. The new Sencore is in two parts: "CRT & Cir- pire steE de strument Gut Model CR 31 "Super Mac" is in the cuit Tester" and "Beam Builder." De- before Cadillac class of CRT tester /re- pressing a rocker switch illuminates youParches ßg76. storers. What it offers are versatility, the section chosen. Testing a CRT ps M lsee simplified operation, a choice of starts with the left section, "CRT & be1O "safe" and "last resort" CRT restora- Circuit Tester." Moving its rotaryfunc- tion steps, and high accuracy. Self -con- tion switch to LINE VOLTS gives the x * FREEI 1976 Stereo Directory & Buying tained in a luggage -type case, the CR user the ac volts reading on a big 6" Guide with the purchase of a Shure V -15 Type II 31 measures 121/4 "H x 11 "W x 7 "D 41/2" color -coded meter. If the TV re- Type III, or the M95 series, M75 or M91 series of cartridges. Simply send (30.6 x 27.5 x 17.5 cm) and weighs ceiver is operating on line voltage us your warranty card with the notation "Send Free Buying Guide" before March 131/4 lb (5.9 kg.). Price is $395.00. below its minimum requirement, a 1, 1976. (Offer subject to supply and may be withdrawn at any time.) JANUARY 1976 CIRCLE NO. SI ON FREE INFORMATION CARD 73

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74 POPULAR ELECTRONICS

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www.americanradiohistory.com step -up transformer can be tried. poor emission, then you can try we were unable to correct one CRT Focus and high -voltage tests can be RESTORATION. The CR 31 offers three with a G1 short, deducing, therefore, made via a built -in 10 -kV probe and, if CRT restoration choices. The AUTO that it was a mechanical problem. So required, a 50 -kV adaptor probe. The CYCLE position applies a constant dc out of nine cases, we restored six TV receiver can be plugged into the voltage between the cathode and the CRT's to satisfactory condition, and instrument's convenient front-panel control grid for about four seconds (a detected one receiver where the fault ac outlet. Determining that the above screwdriver adjustment permits this wasn't with the CRT (it was HV trou- is satisfactory, tests on the CRT itself time to be increased or decreased), ble). can be started. (The foregoing can be then removes the voltage for about 2 The instrument was especially easy bypassed, of course, if the CRT's seconds. The cycle is repeated three to use. The test steps are made in logi- heater doesn't light up.) times while the pushbutton is de- cal order, the number of settings is Using a handy 36 -page set -up book- pressed. Two MANUAL RESTORE posi- minimal, and test results are garnered let stored in the case's compartment tions are also available, where the user most efficiently. We especially liked gives rapid access to all the informa- controls the amount of time the sys- the automatic tracking feature, which tion needed to test and rejuvenate tem is working. In MANUAL 1, maximum didn't require any calibration. The CRT's. This includes listings of CRT cathode current is limited to 100 mA, wide choice of rejuvenate /restore op- types with instrument settings for fil- whereas in MANUAL 2, current is li- erations, running from ultra -safe to ament voltage, bias, voltage range for mited to 150 mA. The latter is a last - risk, was most welcome too. focus and HV, and plug -in socket resort method. About the only negative comments number. After attaching the proper Restoration is actually the reactiva- we could find to make about the CR31 socket to the CRT and connecting the tion of the electron- emitting proper- is that it's not tiny and lightweight, and CR31's coupling to it, you're ready to ties of the CRT cathode, so that it can it costs a lot of bucks. But its size and start. Setting FILAMENT VOLTAGE from 0 emit large quantities of electrons to weight can be handled without trouble to 14 volts and "fine tuning" it with a eliminate degradation due to slight and is well worth carrying along be- FILAMENT- SET control, you simply turn amounts of gas within the tube. cause, unlike other instruments, it can the function switch to HEATER - If emission is satisfactory, a LIFE generate income that you would CATHODE SHORT and read the meter, TEST is made. This lowers the filament otherwise never earn. Even testing a followed by a CONTROL -GRID SHORT voltage so that you can estimate how CRT and showing a customer the re- test. If a short is indicated, you can flip much life is left in the old CRT by ob- sults on the big meter is an important the main selector switch to the BEAM serving meter readings. An AUTOMATIC plus in your favor. Insofar as cost is BUILDER position. This mode is used to TRACKING test is made next, in the CRT concerned, you get what you pay for. clear G1 shorts. Depressing a push- & CIRCUIT TESTER mode. This test is ac- And the CR31 has it all. button discharges a high -voltage complished without any additional With over 10 percent of all TV prob- capacitor between the cathode and balancing or settings by simply mov- lems reported to be due to the big G1. This can be done to any of the ing the function switch to AUTOMATIC tube, having an accurate CRT tester three guns in a color picture by de- TRACKING and noting whether the and restorer is an important asset to a pressing RIB &w, G or B buttons. meter indicates good or bad. Using a TV service technician. Though it might If the CRT passes the foregoing test, Sencore -patented circuit, emission in- initially seem as if the technician will you need simply move the rotary formation for each color gun is stored lose money by restoring a defective switch to GUN BALANCE while in the CRT and compared on the basis of the in- CRT to good operating condition, it & CIRCUIT TESTER mode. Here, each dustry 1.5:1 ratio standard. If the track- can actually make money for the serv- gun's G2 control is adjusted so that ing reads "Bad," then the color pic- icer. Most TV men offer to refund part the meter pointer hits the same indi- ture will either be too green, too blue, or the whole of a CRT restoration bill cated line on the meter, providing the or too red, depending on which gun's when called to eventually replace it lowest emission level. Switching to emission is too low; black- and -white with a new CRT. Thus, there's assur- EMISSION gives a direct meter reading pictures on color receivers also dis- ance that the business will eventually that shows good, bad or ? for each play tinges of color if tracking is poor. come to the servicer in the end, not to CRT gun, measuring true beam cur- mention other service calls for the rent at maximum emission. User's Report. The CR31 "Super satisfied customer and new ones for If emission isn't satisfactory, you've Mac" was in our hands for a few neighbors. It's clear then, that if you're got five cracks at improving it. Firstly, months. Testing a myriad of CRT's going to stay in the TV business, it there are two REJUVENATE positions in with it, we found it to be as complete a pays to own a CRT tester and restorer. the BEAM BUILDER mode. These posi- CRT tester and restorer as one could One has to be sure to forewarn a tions accelerate the beam current hope to use. We brightened up a host customer that there is a risk involved and /or increase filament voltage tem- of formerly low- brightness pictures, before undertaking CRT restoration. porarily to bring new emitting material removed a G1 short, and vastly im- Just as with a medical operation, to the surface of the cathode. Even if proved tracking on many other color there's always a chance that some- you hold the pushbutton down, the TV receivers. (In instances where all thing will go wrong. But without un- system will discharge and, therefore, guns could not be equalized, adjust- dertaking such correction, a new CRT not allow you to use excessive rejuve- ing the set's screen -grid controls did would be needed. Happily, the CR31 nation. (You might also try raising fi- the trick). In one case, we ruined a CRT offers many "safe" restoration tests, lament voltage in delayed steps and using the CR31's MANUAL 2 restora- with only one holding the high risk of testing for emission to see if an im- tion, but this tube was gone to begin final ruin. However, the customer has provement is noted, which is a sixth with. In another instance, however, we nothing to lose at this point anyway. option). If all three CRT guns show "saved" a similar defective CRT. Also, CIRCLE N0. 83 ON FREE INFORMATION CARO

78 POPULAR ELECTRONICS

www.americanradiohistory.com Solid State

By Lou Garner

PROPHECIES FOR NEXT YEAR

IF YOU'RE a newcomer to these pages, let me explain A low -cost electronic calculator designed specifically

that I like to play an annual guessing game with the for the children's market. Right on! Announced mid -1975 electronics industry, predicting what new semiconductor and designed to appeal to children as well as adults with a products will be introduced during the coming year, price sense of humor, Mickey Math'" features a colorful picture trends, and technical innovations. While, over the years, of cartoon favorite Mickey Mouse` arrayed in a sorcerer's my record has been pretty good, the game is doubly dif- costume. Furnished with an illustrated instruction booklet ficult during periods of recession or inflation, because written for the younger set, the instrument is a full fou r- manufacturers may delay the introduction of new prod- function, algebraic logic calculator with a floating decimal ucts, waiting for more favorable markets; and what, nor- and six -digit readout. The instrument is offered mail -order mally, would be price cuts may become a matter of simply by the JS & A National Sales Group (4200 Dundee Road, holding to current prices. Northbrook, IL 60062).

Having made my excuses, let's see how well I did with the An increasing variety of multipurpose consumer and predictions made in last January's column. As many of you office electronic products. Another winner! Space limita- may recall, I predicted: tions prohibit a listing of all the new products introduced A price breakthrough on solid -state imaging devices, during the year, but among the more interesting were and the possible introduction of a low- priced solid -state Garrett's "Incredible Time Machine." Designed for desk video camera. On target! The construction of such a cam- use, it combines in one instrument a signal alarm; digital era from an inexpensive kit was described in this magazine calendar with memory (for special days), full- function cal- in the February, 1975 issue ( "Build CYCLOPS," by Terry culator, digital stopwatch /timer and a digital electronic Walker, Harry Garland and Roger Melen). clock. The "Time Machine" was merchandised by The The development of personal health monitors for pa- Gallery (a division of the Amsterdam Co., Amsterdam, NY tients subject to sudden attacks or seizures. Score a par- 12010). tial. While I envisioned a device about the size of a hearing The development of low -cost portable electronic games, aid, the LEAA (Law Enforcement Assistance Administra- based on calculator technology. Reluctantly, a miss. In my tion) placed a contract for the development of such a opinion, calculator devices could be used in the creation of device about mid -1975. The LEAA contract calls for a de- a variety of both children and adult games which combine vice about the size of a wrist watch that provides a readout skill with chance (or luck, if you prefer). Apparently, the of pulse rate, body temperature and blood pressure. It is industry doesn't agree because, unless I've missed an an- intended to inform law enforcement officers of possible nouncement, no such games have been offered to the physical problems that might interfere with the perfor- general public. mance of their duties during periods of stress. Since the The development of a high -output or high -intensity LED. instrument is being developed under government con- On target again! Several semiconductor manufacturers tract, it may be some time before comparable commercial have introduced high- output LEDs. Data Display Products instruments are available. (5428 W. 104th St., Los Angeles, CA 90045), for example, Digital electronic watches in the range of $50 to $60. offers a number of LED's with a brightness comparable to Another bull's -eye! Not only are a variety of watches avail- that of incandescent lamps (typically, 50 mcd for red, 35 able in this price range, but, by watching for sales or going mcd for amber,and 16 mcd for green). Some of the units to a discount house, you might be able to pick up a nice have built -in resistors and are based so that they can be digital electronic watch for less than forty dollars. used as direct replacements for corresponding incandes- A digital MPG (miles -per -gallon) meter for automotive cent pilot bulbs. applications. Zero on this one! Despite the continuing The development, although not necessarily the com- energy shortage and the ever -increasing cost of gasoline, mercial production, of solid -state energy control centers no manufacturer has introduced such a product as of the for homes and offices. Score another bullseye! Actually, present writing. One firm (SpaceKom, Inc., Box 10, Goleta, sophisticated solid -state energy control systems have CA 93017) has been offering an analog solid -state MPG been available for large scale applications for several meter for some time. While standard vacuum gauges can years, as mentioned succinctly by reader Charles R. Mor- be used, under some conditions, to estimate gas mileage, a ford (of Honeywell, Inc.) in last May's Letters section. Mr. true digital MPG meter for the average motorist awaits Morford, in fact, chided me slightly for my prediction. future development "back at the drawing board." While efficient, however, such systems are expensive and

JANUARY 1976 79

www.americanradiohistory.com possible use of nonvolatile memories to retain programs. THE COMPLETE DVM Today's programmable pocket calculators fall into two categories: those with volatile program memories and those which use accessory devices, such as magnetic

cards, to store entered programs. I feel there is a need for a programmable calculator with an integral nonvolatile

memory. I mean one which will retain an entered program until deliberately erased or modified, even if the unit is switched "off," and which does not rely on external accessories. $348 The introduction of pocket calculators featuring internal access connectors or jacks. Considering the overall FOR FASTER, MORE capabilities of pocket calculators, the addition of I/O RELIABLE MEASUREMENTS (input/output) connectors would greatly increase their versatility. Such jacks would permit their use as counters, A NEW STANDARD IS BORN HI and LO ohms and a 50KVDC range for example, or permit data to be recorded on High accuracy you can trust . . . with accessory Hv probe. accessory Versatile measuring capabilities . . A NEW STANDARD IN SPEED equipment. In addition, an output jack would permit a

An efficient, easy to operate meter . . . AND EASE OF OPERATION All at an affordable price . pocket calculator to be used as a portable control unit for Large pushbuttons and callouts - no That's the DVM38. .. The complete need to hunt and peck. Large .4" various types of electronic instruments or as an input de- DVM that sets new performance stan- L.E.O: s with direct readout, down to dards in 4 key areas. vice for computers and microprocessors. V and mV indicators. SINGLE STEP A NEW ACCURACY STAN DARD AUTO- RANGING for maximum resolu- The development of higher density memory chips. Con- The 3% .1% accuracy is backed by digit, tion and efficiency. 2KV DC protection a 15 siderable work is already in progress in this area, meg S2 input impedance, compared minimizes downtime. with to 10 meg St input of conventional several firms reporting positive results. Utilizing a combi- OVM's, which guarantees up to 50% THE AFFORDABLE STANDARD greater accuracy with 1/3 less circuit There are few .1% DVM's less expensive - nation of ion implantation and electron -beam lithography loading on every measurement for high there are none as complete in this price techniques, IBM's Research Division, for example, has al- accuracy you can trust. range, plus backed by a LIFETIME guarantee against factory A STANDARD IN CAPABILITIES workmanship errors. ready achieved a ten -fold increase in the packing density The DVM38 is more accurate in MORE THE DVM38 A NEW of LSI memory chips on an experimental basis. The IBM circuits with these versatile ranges: STANDARD IN DVM's FOR SPEED, 100nV to 2000V DC, 1KV AC; .01 St process permits the fabrication of memory chips with a VERSATILITY AND ACCURACY. to 20 meg S2 ; 0.1nÁ to 2A ... Plus storage density of five million bits per square inch. BACKED BY SENCORE'S 100% The use of microprocessor IC's in automotive applica- DVM38 MADE RIGHT LIFETIME GUARANTEE tions, at least on an experimental basis. With its powerful

zoo Sencnre o sum rzu s s o 611037 computational and control capabilities, the micro- ln.Phone 1605 739ve010o T Wx 910 660 0700 processor is a for monitoring such things as CIRCLE NO. 50 ON FREE INFORMATION CARO "natural" spark intensity, air /fuel ratio, engine speed, oil pressure, their use is limited, for practical purposes, to large com- oil, coolant, atmospheric and engine temperatures, at- mercial operations. What I had in mind was an effective mospheric pressure, relative humidity, exhaust charac- control center for the average home or small office as a teristics, and engine loading, making automatic adjust- substitute for, say, a conventional bi- metallic electro- ments to achieve optimum overall performance. Such mechanical thermostat. Happily, a major semiconductor units also could serve to monitor critical areas and to alert manufacturer has developed just such an instrument. Al- the driver to possible danger or the impending need for though not yet in commercial production, the unit utilizes a repairs. solid -state temperature sensing IC, an SCR, a triac, and A substantial drop in the prices of microprocessor and several diodes, and is intended for use as a direct replace- memory lC's. This will occur despite a continuing inflation- ment for conventional thermostatic controls. ary trend. As the costs of microprocessors and memory chips drop, these devices will become increasingly popu- Things to Come. Having missed a couple of my predic- lar for experimenter and hobbyist projects. There should tions for 1975, I suspect that either my crystal ball has a be a corresponding drop in the prices of minicomputers, hairline crack or that there is a defective PROF (prog- whether factory -assembled or in kit form. rammable read only future) IC in the support circuitry. The introduction of a moderately priced thermoelectric Despite my qualms, here goes for 1976: module for the experimenter and hobbyist market. The The introduction of additional special -purpose cal- response to our discussion of TE modules in last culators utilizing nonvolatile memories (similar to the one February's column was so great that we feel sure that some used in the Mostek CheckMasterT't). Perhaps it might be a progressive manufacturer will recognize the market pos- calorie counter for weight- watchers, a perpetual inventory sibilities of a moderately priced device. Chances are the unit for stores and manufacturers, or a mileage /trip ex- device, when offered, will carry rather broad "specs," as pense calculator for travelers and business men. did the early experimenter's transistors. Digital electronic watches retailing for less than $25.00-despite continuing protestations from industry Readers' Circuits. If reader response is any criteria, LED officials that the "electronic watch market will not follow flasher circuits continue to be very popular with ex- the path of the calculator market." Where there's a market, perimenters and hobbyists. Among recent contributions is there's a way, and Timex, among others, has demonstrated the dual flasher circuit in Fig. 1. Submitted by Ferdi Baler that there is a market for inexpensive watches. (1551 A. Day Ave., San Mateo CA 94403), the circuit fea- More so than in previous years, 1976 should be the year tures a type 74123 TTL dual monostable multivibrator, ICI, of the programmable calculator, with an expansion in the and is designed for operation on a standard 5 -volt dc variety of types offered, a general drop in prices, and the source.

80 POPULAR ELECTRONICS

www.americanradiohistory.com +5V Raptly i trEittPnntttl '76 Çar;ogo1 ríP ,:n w Stir Tes for fast, non -shorting access Fig. 1. Dual LED to all leads on dual -in -line flasher circuit. IC packages Several of these No more shorting across can he cascaded .for DIP leads... just quickly clip on an IC TEST CLIP sequential flashing. to bring DIP leads out for safe attachment of scope probes and other leads. Ideal for signal input, trac- NC: ing, troubleshooting, etc. PINS 2 -4, 10 -12 TC- 16 fits 16 -pin DIP's, err Patented precision, "contact comb" design guar- The circuit's flashing rate is determined by the two RC Part antees no shorting be- Model Row -To- Price values may be Row Dim. Number tween DIP leads. Probes time constants, and different capacitor can hang "no- hands" free TC-8 .3 IN. 923695 87.35 used, if desired, to adjust the rate to meet individual re- TC-14 .3IN. 923698 4.50 on Test Clip terminals in card racks (unique see quirements. The resistors are 1/4- or 1/2 -watt types, the TC-16 .3 IN. 923700 4.75 - TC-16 LSI .5/.6IN. 923702 8.96 photo). Engineered Me- capacitors 5 -to -10 volt electrolytics. Select current - TC-18 .3 IN. 923703 10.00 chanical clamping plus TC-20 .3IN. 923704 11.55 resistors R1 and R2 (generally 100 to 400 ohms) to gold -plated phosphor limiting TC-22 .4IN. 923705 11.56 provide TC-24 .5/.6IN. 923714 13.85 bronze terminals produce equal brightness in both LED's. TC-28 .5/.6IN. 923718 15.25 superior electrical con- According to Ferdi, his design differs from previously TC-36 .5/.6IN. 923720 19.95 tact. Also unequaled as a TC-40 .5/ .61N. 923722 21.00 DIP removal tool. published circuits in that several of the flashers may be All products guaranteed to meet or exceed published specifications. cascaded for special effects. Simply open the connection

between pins 1 and 5 and, instead, connect pin 5 of the first ? -.Boo t ,1A IC to pin 1 of the next, continuing to the last IC and finally s ' 5 IC d+'chgh t`fpuder completing the loop by connecting pin of the last back . _CUI - erostrip to pin 1 of the first. With this arrangement, the various LED's will flash in sequence, with on -times proportional to Sup_ the R -C time constants in each stage. Cascaded multi- stage flashers may be used in direction indicators, advertising displays, and in similar applications. One of our overseas readers, Yves Soussi (15 parc de Bearn, 92210, St. Cloud, France), contributed the touch - switch circuit in Fig. 2. It is designed to switch a-standard ac load, such as a lamp, fan motor, or display actuator, on fastest, most reliable or off each time a pair of conductive terminals is touched method known...to build, test lightly. The circuit is of particular interest because it and modify experimental circuits utilizes an IC in conjunction with a variety of discrete semi- 8 -bus distribution system High -performance A P Super - conductor devices -a transistor, triac, and diode. plus universal .1" by .1" matrix Strip component matrices consist of solderless, plug -in tie points of 128 terminals of 5 tie points In operation, ICI , a dual "D" type flip -flop, provides two all in one integral device. each. The 8 buses of 5 connect- functions. Half of the IC serves as a monostable circuit, ed 5- -point terminals are for all and discretes tie Accepts DIP's ground, reset and clock actuated by impulses received from the touchplate, while with leads up to ,032" dia. voltage, lines, shift command, etc. New, the other half acts as a divide -by -two counter. The counter Interconnect with any solid wire non -shorting, instant -mount up to No. 20 A.W.G. backing and quick -removal screws are supplied... use several ORDER BY PART NUMBER Super- Strips to create large -scale 9232521nickebsilverterminels1 $17.00 breadboards on panels up to 923748 (gold -plated terminals) $18.90 1/8" thick. SEND ORDERS TO: aP A P PRODUCTS INCORPORATED Box 110 -H Painesville, OH 44077 216/354 -2101 DEALER INQUIRIES INVITED A P PRODUCTS INC. QTY PART NO. 8 EACH 8 TOTAL Box 110 -H, Painesville, OH 44077

7 naster cM,ga BankAmencard ¡ Et Master Charge l`---- e honored s

ACCOUNT NUMBER Merchandise Total Sales Tax (OH Er CA) 4 NO ABOVE NAME IMCI GOOD THRU Shipping (see below)

SIGNATURE TOTAL ENCLOSED SHIPPING /HANDLING ORDERS PRINT NAME Up to 910.00.... $1.00 SUBJECT 810.01 to 25.00... 1.50 TO ACCEP 25.01 to 50.00 ....2.00 TANCE AT ADDRESS 50.01 to 100.00 . .. 2.50 Fig. 2. Touch- switch circuit uses an integrated 100.01 to 200.00 .. 3.00 FACTORY P.O.'s F.O.B. Painesville) circuit in conjunction with discrete devices. CITY STATE ZIP Company

JANUARY 1976 CIRCLE NO. 1 ON FREE INFORMATION CARD 81

www.americanradiohistory.com SystemsResearch,Inc. circuit furnishes base current to Q1 which, in turn, supplies a gate signal to the triac, switching ac power through the load. Basic circuit power is furnished by a 9 -volt transistor battery, with load power supplied by an ac line. Yves has specified standard, easily available components in his design. The IC is a COS /MOS type CD40 -13 (RCA), Q1 a 2N2222 general -purpose npn transistor, D1 a 1N647 or 1N914 diode, and the triac an SC 142 (GE). In practice, almost any sensitive gate triac can be used with the control circuit, provided its current rating is adequate for the external load. Actually, S1 may be omitted, if desired, for the control circuit's.current drain is quite low. The touchplate is a hand -assembled unit consisting of a small piece of insulating material, such as perf board, and Systems Research, Inc. a pair of small conductors, such as metal thumb tacks, presents - copper strips, machine nail A Complete screws, or heads. Microcomputer for only *$575. The circuit's layout and lead dress should not be overly The SRI -500 critical but, of course, good wiring practice should be Includes TTY and RS -232 interfaces. Connects to any 20MA loop teletype. Enclosed observed. The in a compact, desk top unit, It contains 1K (word) RAM", expandable Prom, power standard precautions applying to MOS type supply and extra main board connectors to accept many options. The SRI -500 serles devices should be followed when wiring the IC in place to Is designed around the new Moslek F -8, an 8 bit processor with a designers development program residing in the program storage unit, making programming an easy avoid damage. For safety's sake, the isolation transformer task even for the inexperienced user. must be used between the circuit's ac terminals and the Special Introductory offer Additional Ram available power line.

Available Options Device News. If you're working with All items completely assembled and tested - /Product equip- SRI -510 Keyboard (provides allow 60-90 days delivery time. All items full keyboard control) shipped postpaid. ment using nickel- cadmium batteries, you'll find it worth- $125 Send Cash or check for while to investigate the ICM7201 low- battery -voltage indi- SRI -520 Video Interface (RE ea. SRI-500 $ _ea. SRI -510 $ or Video) __ea. SRI -520 $ ea. SRI -530 $ cator. Manufactured by Intersil, Inc. (10900 N. Tantau Ave., $175 SRI -530 Casette Interface Mastercharge e Interbank N Cupertino, CA 95014), the device is a monolithic IC com- BankAmericard a Exp Date $ 75 Signawre prising four npn transistors and seven internal resistors. Complete Blackjack game program to demonstrate or Systems Research, Inc. Assembled in a 4 -lead TO -72 case, the ICM7201 isdesigned exercise the SRI -500 P.O. Box 151280 (Specify paper tape or to switch an external LED on whenever its source voltage Salt Lake City, Utah 84115 Casette) free with order (801) 942-1093 drops below 2.9 volts, the recommended warning level for of SRI -500 (limited offer) a rechargeable 3 -cell nickel- cadmium battery, thus alert- CIRCLE N0. 57 ON FREE INFORMATION CARO ing the user that a recharge is needed. RCA's Solid State Division (Box 3200, Somerville, NJ 08876) has announced the commercial availability of a new microprocessor family featuring CMOS technology. In- cluded in the family are the CDP1801 CMOS 8 -bit micro- Now... processor, a "Microkit" hardware support kit, microprocessor manuals, and software development packages. $50 VOM The CDP1801's low power requirements (60 mW typically at 2 MHz) and broad supply -voltage tolerance (3 to 15 volts features dc, unregulated) makes it particularly appropriate for automotive and portable equipment applications. The full - for only voltage version is available at $56.00 each in unit quantities, while a special 5 -volt version, type CDP1801C, is $19.95* offered at $40 each in small quantities (1 to 99). We'll stack up our If you are considering assembling your own calculator, new, economical WV -547A against keep in mind the DS8864 display driver introduced recently any other general purpose by the National Semiconductor Corp. (2900 Semi- VOM for to $50. Here's selling up why: conductor Drive, Santa Clara, CA 95051). A LED- to -MOS Large, no- stick, taut -band, diode -protected meter. Accuracy t 3% DC, ± 4% AC with 20,000 Ohms /Volt interface device that includes a battery- condition sensing DC sensitivity. circuit, the DS8864 requires only 900 to 1200 pA drive 5 functions, 19 ranges, with 1% precision resistors current, yet contains nine independent digit drivers de- on all ranges. Rugged, high- impact plastic case. signed to sink up to 50 mA from a common -cathode LED Includes test leads. Carrying case also available. display operating in a multiplexed mode. The unit's built -in See the WV -547A for yourself at any one of the more battery- condition sensing circuit turns on the decimal than 1,000 RCA Distributors worldwide. Or contact: RCA Distributor and Special Products Division, Bldg. point of the left -most digit when the battery voltage drops 206 -2, Cherry Hill Offices, Camden, N.J. 08101 below 6.5 volts. The DS8864 is supplied in a 22 -pin Epoxy -B (Phone 609 779 -5715) DIP. The only other components needed for a complete 'Suggested Price calculator are a 22- position keyboard, a spst switch, a Electronic 9 -volt battery, a MM5738 calculator IC, and an NSN -98A nell Instruments 9 -digit LED display unit.

CIRCLE NO 46 ON FREE INFORMATION CARO 82 POPULAR ELECTRONICS

www.americanradiohistory.com replace noisy resistors or transistors to get the best noise level (the largest number of dB on the output voltmeter when the noise generator is on) out of Test Equipment the receiver. Pruning an Antenna. R -f noise can also be used to prune an antenna for cam-- Scene maximum efficiency. In this case, a noise bridge is used and the proce- By Leslie Solomon dure will be of interest to CB'ers who want to get the most out of their limited transmitter power. Many people MAKING GOOD USE OF NOISE have worked on their antenna with an SWR bridge to get conditions as good F YOU ask a typical electronic aware that noise makes a dandy tool in I as possible, but they still can't get a hobbyist or service technician testing? A circuit that deliberately 1:1 ratio. to list the electronic problems that generates noise is shown below. It There are several commercial noise there is a generates a controllable (by the give him the most difficulty, bridges available, usually consisting good chance that circuit noise will be potentiometer) amount of noise (the of a wide -band r -f noise generator to somewhere near the top. Most of us same as the hiss you hear when a re- drive a bridge. The bridge then com- consider noise the bane of our exis- ceiver is not tuned to a station) just pares an unknown impedance (in this tence. We can determine that it exists about evenly distributed across the r -f case the antenna) against a calibrated in a circuit; but the problem is to find a spectrum. potentiometer. The receiver is then cause and a remedy. used as a tunable null indicator to de- In discussing noise, the first thing to termine when the antenna is really do is define what we're talking about. matched to the desired frequency. of this There are a number of sources With the noise bridge driving the an- troublemaker, among them is thermal tenna, all you do is tune the receiver a result of the random mo- agitation, for the deepest null and read the an- molecules. This motion occurs tion of tenna impedance off the calibrated is at a temperature in all matter that potentiometer dial. Now you can de- zero. Such noise is in- Essentially the circuit is a forward - above absolute termine whether the antenna is cut for is propor- dependent of frequency and biased diode whose fluctuating cur- the desired frequency and what the to ( °K) tempera- is a load resis- tional the absolute rent generated across impedance really is. Armed with this deter. The value the load resistor is the ture. (Remember those cryogenic of information, you can then hack and used in antennas ?) same as the input impedance of the vices deep space chop until your antenna is on the but- The noise is also proportional to the receiver or other device being tested. ton and doing a good job. In this way, resistive component of the impedance To use the to determine the circuit whip antennas can be matched to the thermal agitation is noise level of a receiver (for example), across which mobile rigs to improve transmission (the start by connecting an audio - produced and the bandwidth range. the the more voltmeter, which has a de- wider you open window, frequency A noise bridge can also be used to dirt comes in). scale, to the receiver's audio cibel check noise levels in audio equipment A second type of noise is shot noise, terminals. output and see if resistor and /or transistor re- which is a result of uneven cathode Connect the noise generator, with placements would improve audio emission in vacuum tubes, or the power off, to the receiver antenna quality. recombination noise in many types of terminals making sure that the load semiconductors. resistor you choose is the same as the The list of noise sources goes on receiver input impedance. Turn the COMING UP IN and on, but the result is always un- receiver on with the agc off. Then set THE FEBRUARY wanted noise. To keep the noise the r -f and audio gain controls to ob- down, many circuit designers use tain a clearly identifiable dB indication "low- noise" resistors in the front end on the meter. (Be sure you are not Popular Electronics' of the circuit. (Keep in mind that every- tuned to a station.) This will be the BUILD THE TV DAllLER thing that shows up in the first stage is reference noise level. Turn on the amplified in later stages -internal noise generator and adjust its poten- PHOTOPHONE LIGHT COMMUNICATOR noise as well as the desired signal.) A tiometer to get a just -perceptible in- THE 1916 COLOR TV RECEIVERS similar design device is to use FET's crease in the hiss level. Note the ratio HIGH -POWER MOBILE STEREO (which have no real recombination the two meter indications. of AMPLIFIER noise) in the front end instead of bipo- This approach, though not allowing lar transistors. the measurement of the actual noise TEMPERATURE METER FOR $15 level due to the diode being used, will PRODUCT TEST REPORTS: Using Noise in Testing. There is, allow you to compare the noise levels Dual Stereo Cassette Deck actually, a bright side to the noise of two receivers. It will also allow you Jensen OPC -21 Speaker System problem, despite what you might think to "fine tune" the receiver's front -end Browning Golden Eagle Base Station about the unwanted intruder. Are you circuits. Then, if necessary, you can Triplett Model 60 VOM JANUARY 1976 83

www.americanradiohistory.com The better the training the better you'll

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As an NTS student you'll acquire the know -how that This electronic gear is not only designed for train- comes with first -hand training on NTS professional ing; it's field -type - like you'll meet on the job, or equipment. Equipment you'll build and keep. Our when you're making service calls. And with NTS courses include equipment like the NTS /Heath easy -to -read, profusely illustrated lessons you learn Digital GR -2000 Solid State color TV with first -ever the theory behind these tools of the trade. features like silent varactor diode tuning; digital Choose from 12 NTS courses covering a wide range channel selection, (with optional digital clock), and of fields in electronics, each complete with equip- big 315 sq. in. ultra -rectangular screen. ment, lessons, and manuals to make your training more practical and interesting. Also pictured above are other units - 5" solid state oscilloscope, vector monitor scope, solid -state ster- Compare our training; compare our lower tuition. eo AM -FM receiver with twin speakers, digital multi - We employ no salesmen, pay no commissions. You meter, and more. It's the kind of better equipment receive all home -study information by mail only. that gets you better equipped for the electronics All Kits, lessons, and experiments are described in industry. full color. Most liberal refund policy and cancella- 84 POPULAR ELECTRONICS

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SIGNAI, GENERATOR DIGITAL 5" OSCILLOSCOPE SOLID-STATE 2 -METER FM MULTIMETER SOL D -STATE TRANSCEIVER & POWER SUPPLY POCKET RADIO tion privileges spelled out. Make your own com- w = = s N S 7 NATIONAL TECHNICAL SCHOOLS Dept.- - 205 -016 parisons, your own decision. Mail card today, or 4000 South Figueroa St., Los Angeles, Calif. 90037 clip coupon if card is missing. Please send FREE Color Catalog and Sample Lesson. NO OBLIGATION. NO SALESMAN WILL CALL. Color TV Servicing Electronics Technology NO OBLIGATION. NO SALESMAN WILL CALL B & W TV and Radio Servicing Computer Electronics Electronic Communications Basic Electronics 1 APPROVED FOR VETERAN TRAINING FCC License Course [1 Audio Electronics Servicing Get facts on new 2 -year extension NAME AGE 1

ADDRESS APT # 1 NATIONAL SCHOOLS CITY STA -E TECHNICAL -TRADE TRAINING SINCE 1905 I Please fill In Zip Code for fast service Resident and Home -Study Schools Check if interested in G.I. Bill information. 4000 So. Figueroa St., Los Angeles, Calif. 90037 Check if interested ONLY in classroom training in Los Angeles. IN - I= E ME MI E MI -- dl JANUARY 1976 87

www.americanradiohistory.com interrupted program to be re- activated. Computer Bits An elegantly simple interrupt system is used in the popular Intel 8080A microprocessor. As shown in Fig. 2, the external signals are applied to an input called INT (interrupt). When the computer is about to fetch the next

INTERRUPT By Jerry Ogdin SOURCE 1 CALL INSTRUCTION DATA BUS 1 INTERRUPTS AND REAL -TIME TO ROUTINE?

HOBBYIST applications of com- can be made to in a sit loop, sampling CPU AND puters fall into two general some input signal until the appro- CONTROL categories: intellectual pursuits and priate event occurs to activate the rest LOGIC practical uses. In intellectual pursuits, of the program and produce (hope- simplicity is generally the keyword fully) the appropriate response (see INTERRUPT and all the unessential details are Fig. 1). However, this simple scheme INT SOURCE N stripped away to reveal the underlying limits the computer to handling one CALL INSTRUCTION _J simplicity. In practical (real) applica- and only one chore at a time. The TO ROUTINE N S INTA tions, however, we can't afford that major virtue of a computer is its ability ENABLES INSTRUCTION/ luxury, and it is in these useful areas to do many things and do them all fast. ONTO DATA BUS that the realities of "real time" opera- It seems a shame, then, to limit the Fig. 2. Diagram shows how the tion strike home. entire computer to continuously ex- interrupt works in the 8080A. In any computer, the instructions ecuting one sequence of input testing instruction in sequence, it senses the are sequentially executed until the instructions. INT condition and does two things: it specific goal is accomplished, and all If you want to install a computer in issues an interrupt acknowledgement this happens without regard to the the basement to monitor and control signal (INTA) which allows the exter- onward march of time. However, once many of the sub -systems in the house nal hardware to supply an instruction you are forced to write a program that (heating and air conditioning plant, to the CPU instead of the memory; and must finish within some limited burglar and fire alarm system, night it inhibits the incrementing of the in- amount of time, you are in the "real lights, and a small diskette file that ternal program location counter. time" domain. A computer program to holds your family financial records, for Otherwise, instruction execution pro- read thermostats once every fifteen example), you will need to "service" a ceeds normally. minutes is not difficult at all. But a wide range of input signals. Any of The interrupting equipment is then program that is required to shut off a these signals can arrive at any random responsible for supplying the CPU valve when water reaches a certain time, and unless you can afford to ig- with an instruction in the 8080's ar- level must be very short, unless you nore some of them it is important that chitecture. The interrupting hardware want to risk a flood. you create a hardware and software places an eight -bit instruction on the In real -time programming, it is gen- combination that is foolproof. This data bus whenever the interrupt ac- erally not too difficult to write a pro- can be done with the interrupt cir- knowledge signal (INTA) appears. This gram that can perform the required cuitry of the computer or micro- instruction is a subroutine call which work in the allotted time and produce processor. causes the current program location the requisite output signals. What is An interrupt is a special kind of ex- counter contents to be pushed onto difficult is sensing the external condi- ternal signal that notifies the compu- the stack in memory and is the first tions so that the program can be acti- ter to pause in its current task, do step in the process called "preserving vated. Ideally, the real -time program something else for a while and then the state of the program." After the resume the interrupted task. For ex- subroutine call instruction preserves ample, if you are reading a newspaper the interrupted program's next - and the phone rings (you answer, talk, instruction address, it places a hang -up and resume reading the specified address into the program newspaper), you've been interrupted. counter; that is the address of the in- Similarly, when the computer is ex- terrupt servicing program. At this ecuting a program to compute and point, the interrupt servicing program generate some output, we should de- may not modify anything in the com- sign the hardware and software to be puter or memory without tampering interruptable. Then, when some new with the execution of the interrupted external stimulus comes along (via the program. interrupt hardware), the currently ex- When any program is in execution, ecuting program is suspended and the part of the status of that program is in interrupt- servicing software is acti- the CPU's registers. The contents of vated. When the interrupt service sub- the program location counter and the Fig. 1. Rea -time looped program. routine is finished, it will cause the accumulator and the flag bits are all

88 POPULAR ELECTRONICS

www.americanradiohistory.com important. If any of these is changed memory. The execution of a sub- from outside the program, then the routine return instruction will cause QUICK.... program's correct execution is nearly the interrupted program's program always prevented. The interrupt ser- location counter to be restored. The what number is this? vicing program must preserve this interrupted program then continues part of the interrupted program's as if nothing had happened. O OO o status, and in most computers there There is a potential problem that are instructions that allow the state to arises at the interface between the If you have to read your microcomputer be preserved by copying the CPU re- real -time interrupt servicing program like this --bit by bit, from rows of lights --the gisters into memory (Fig. 3). It is this and the non -real -time "background" computer's making you do its work. And if particular operation that the 8008 is software. There is a part of each you have to use rows of toggle switches to unable to perform without some extra routine, called the "critical section" program it, you might wonder why they outside hardware. The 8080, however, where confusion may reign unless call the computer a labor -saving device! has a set of instructions for preserving some care is taken. Imagine the worst the state of the computer; for exam- possible case: the interruptable pro- Contrast the layout of a typical pocket A each and ple, the PUSH instructions save the gram is interrupted just at the instant calculator. key for number function; six easy -to -read digits. Why not relevant information in the stack. The that it is about to examine the interrupt microcomputers like that? 6800 microprocessor automatically counter. In most computers, the design preserves the entire state of the CPU counter must be fetched up from on the stack whenever an interrupt is memory into a CPU register to be ex- sensed. amined and decremented and then re-

INTERRUPT SERVICE ROUTINE

(INTERRUPT #7)

ORG 56

COMES HERE TO SERVICE INTERRUPT AUTOMATICALLY

PUSH PSW PRESERVE STATE Fig. 3. Routine to PUSH B OF INTERRUPTED allow state to be PUSH D PROGRAM preserved by copying PUSH H the CPU registers Here they are! The modular micros from into INTERRUPT SERVICE ACTIONS HERE the memory. Martin Research. The keyboard programs

LXI H,COUNT the computer, and the bright, fully - data and memory INR M decoded digits display addresses. A Monitor program in a PROM

POP H , RESTORE STATE makes program entry easy. And, even the D POP smallest system comes with enough RAM POP B memory to get started! POP PSW Both the MIKE2 system, with the popular EI , RE- ENABLE INTERRUPTS 8008 processor, and the 8080 -based MIKE RET , GO BACK 3 rely on the same universal bus structure. This means that accessories --like our 450 After the interrupted program's stored to memory. This sequence ns 4K RAM --are compatible with these state has been preserved, the interrupt must not be interrupted. If it can be and other 8 -bit CPUs. And, systems start servicing program performs its work. interrupted, you may not get the ex- at under $300! For details, write for your... Generally, the minimum amount of pected results. The best way to avoid work is accomplished. The longer the this problem is to prevent the inter- FREE CATALOG! interrupt servicing program takes, the rupts from being serviced while the more likelihood there is that some interrupt counter is being examined or MIKE 2 other interrupt will be lost. The abso- modified (Fig. 4). There are instruc- MANUAL... lute minimum is to record the fact of tions in all computers that can be used This looseleaf the interrupt somewhere in memory. to disable and then re- enable inter- book includes Each time the interrupt occurs, a spe- rupts. full information cific location in memory is incremen- The interrupt then, is basically a on the MIKE 2 ted by one; and, whenever the interrup- hardware trick to allow us the illusion system, with table softwear gets time, the counter of having two or more different schematics. received is examined and the appropriate ac- cooperating computers sharing a Price for orders by November 15, 1975... tions are taken. The interruptable soft- common memory. It is important not $19 Includes a certificate worth $10 towards ware then decrements the counter by to let the interrupt service routines do a modular micro system, good 90 days. one to account for the action taken. too much as they may be difficult to (Offer valid, USA only.) After l 1 / I5: $25. After the interrupt servicing routine debug if they are complex, and the is finished, the entire state of the com- effects of the bugs may be obscure modular micros martin research puter is restored to the conditions that and seemingly unrelated. If the inter- existed prior to the interrupt. The re- rupt service routines are simple, they Martin Research / 3336 Commercial Ave. gisters of the CPU are restored from will be easy to "prove" correct without Northbrook, IL 60062 / (312) 498 -5060

JANUARY 1976 CIRCLE NO 35 ON FREE INFORMATION CARO 99

www.americanradiohistory.com (Interruptable) (Interrupt Service) TV DAZZLER

MEMORY (assume counter = 5) Our 4KRA -4 Static Memory accumulator.-- counter; Modules are being used by both the I hardware and preserve state of computer; software designers of Interrupt strikes here the TV DAZZLERTM Color Graph- counter counter + 1 ; ics device. This 4096 word LOW POWER Static RAM Memory is restore state plug -in compatible with the Altair ' 8800, and is the most reliable Read/ accumulator.-accumulator - 1 ; Write Memory on the market today. Don't be misled by "undirected" c,ounterarcumulator ; statements, the 4KRA -4 uses less (ccunter r 5!) POWER than any 2K word Static Memory using 2102 or 8101 memory IC's and under worst case conditions only slightly more than dynamic memories. The 4KRA-4 can even store data reliably when powered by Fig. 4. Instructions can be used to disable just two standard "D" cells! and then re- euab(e interrupts. NEW LOW PRICE! $139.00 - much ado. Interrupts, like any other California MASS STORAGE riches, can be overindulged; so resist Homebrew Computer Club, 193 Thompson We've got the least expensive the impulse. Sq., Mountain View, CA 94043. efficient method for storing and Sacramento Minicomputer Users, Box 741, retrieving DAZZLER programs and Citrus Heights, CA 95610. pictures. Our CDS VIII Cassette Data We Get Letters. Since we intro- Systems uses standard cassettes to duced the HIT (Hobbyist Interchange San Diego Computing Society, c/o Gary give you fast access to up to 600,000 Mitchell, Box 35, Chula Vista, CA 92012. Tape) system in our September 1975 data characters or program instruc- Southern California Computer Society, tions. That's enough storage for a lot column, we have received a consider- Box 987, S. Pasadena, CA 91030. of DAZZLER patterns! The CDS able amount of mail concerning it. VIII System includes one or two high UCLA Computer Club, 3514 Boelter Hall, speed multiple motor cassette trans- There are a number of such cassette UCLA, Los Angeles, CA 90024. ports, transport controller, and inter- systems, each manufacturer using his 29 Palms Area, Sgt. Wesley B. Isrigg, Box face to the 8800 computer. This own scheme. At a November meeting 3558, C&E Schools M.C.B., 29 Palms, CA complete Mass Storage System is packaged in an attractive, rugged in Kansas City, Mo., an effort was 92278; or Sgt. Stanley E. Herr, 13 -C Cop- enclosure. made to establish a standard format. per Dr. M.C.B., 29 Palms, CA 92278. We are working on a comprehen- Colorado sive Cassette Operating System pro- Looks like a 1200/2400 -Hz system will The gram we call PTCOS. PTCOS lets you be adopted. Well keep you posted on Digital Group, Box 6528, Denver, CO create program files and handle large the future developments. 80209 blocks of data when running BASIC Illinois The HIT format was not suggested or Assembly Language programs. Chicago Users Group, c/o Robert Swartz, With PTCOS the computer thinks the as a computer industry standard, but 195 Ivy Lane, Highland Park, IL 60035. CDS VIII is a floppy disk! as a simple, low -cost, easy -to- Massachusetts implement system for hobbyists so DAZZLER CONSOLE Boston Area, c/o John Vullo, 21 Sunset that they could exchange data and To control the DAZZLER effec- Ave., N. Reading, MA 01864. tively, some kind of control console programs. In fact, one supplier of OEM Minnesota device is needed other than the 8800 kits (Cramer Electronics) has its soft- Bit Users Assoc., Resource Access Center, front panel switches. You could use a ware recorded in the HIT format, and a c/o Richard B. Koplow 3010 4th Ave. So., teletype, but TTY's are expensive, Minneapolis, MN 55408. noisy, and waste paper. Why not use HIT interface is included in their kits. an inexpensive black and white TV Southeast Minn. Amateur Computer Club, monitor and our plug-in compatible News Items. AMD announced an 2122 NW 17 Ave., Rochester, MN 55901. Video Display Module? The VDM -1 New Jersey take data from any of your input OEM price reduction on its 8080A (to will Amateur Computer Society of N.J., 72 S. devices, whether TTY keyboard, tape below $30), and Intel followed suit. Railroad Ave., Staten Island, NY 10305. or disk. It provides all the necessary Then, Texas Instruments announced circuitry to generate sixteen lines of Ohio 64 characters each with both upper its 16 -bit 9900. Not due until March, "Universe Unlimited" Users Group, c/o lower letters. The display and case the 9900 operates at about the same John E. Kabat, 11918 Forrest Ave., Cleve- format is much easier to read than speed as the 8080, but will probably any ordinary TV Typewriter, and the land, OH 44120. VDM -1 displays twice as much data cost about $50. When price reductions Oklahoma per line! start on the OEM level, they eventually Oklahoma City Club, 2412 SW 45th, Ok- Our display module provides real lahoma City, OK 73119. power to write, format, and edit any sift down to the hobbyists. Pennsylvania type of program. Driving software is included FREE! Hobbyist Clubs. Information on Pittsburgh Area Computer Club, c/o Fred computer hobbyist clubs continues to Kitman, 400 Smithfield St., Pittsburgh, For more details on these and other 15222 come in. In addition to the ones listed PA 8800 plug - in compatible modules, Texas write to: below (to which we will add from time Texas Computer Club, c/o L. Walker, Rt. 1, ©Processor Technology to time), check out your local high Box 272, Aledo, TX 76008. 2465 Fourth Street schools and universities. Many of Canada Berkeley,Ca.947)0 them have clubs which were formed Canadian Computer Club, c/o G. Pearen, by students, with outsiders generally 861 11th St., Brandon, Manitoba, Canada welcome to join. R7A 4L1. CIRCLE NO. 45 ON FREE INFORMATION CARD POPULAR ELECTRONICS

www.americanradiohistory.com BY SHERMAN P. WANTZ CB Scene

HOW TO USE CB RADIO "BUZZ" WORDS..

INTERSTATE truckers, abetted by a grow- The glossary below has been developed to it as they develop among the truckers. ing number of mobile and base station to help CB newcomers interpret the special Using CB jargon correctly is interpreted operators, meet each day, on Citizens terms used most frequently on the inter- by some as a mark of sophistication. Any- Band (CB) channel ten. They use a state highway channel and elsewhere in time you cannot remember the "proper" colorful -often cryptic -language to the CB Class D frequency spectrum. Save term to use, however, plain old everyday communicate with one another. this list and add new terms and meanings English will do. Even on channel ten.

TERM MEANING TYPICAL USE TERM MEANING TYPICAL USE Back Over Back to you. Come again Repeat your last trans- Come again? mission Back door Rear of vehicle I'm watching your back door (protecting you from Comeback Return call Thanks for the comeback. being overtaken un- Come on Over, invitation to What's your twenty? awares by police). transmit Come on. Back down Drive slower Smokey's ahead. Better County Sheriff's deputy Two county mounties are back it down. mounty parked under the bridge. I'm of Back out Stop transmitting going to back out Covered up Interferred with You were covered up here. that time I'm running this rig Barefoot CB set output signal Cut the coax Turn off CB set I'm going to cut the not additionally am- barefoot. old coax now. plified. Bodacious Shamelessly strong You've got a real boda- Base station CB set operated from I'm operating here from acious signal up here. a fixed location my base station. Ears CB set Got your ears on? Beam Type of directional I've got my beam antenna on you now. Eighteen Truck and trailer How about that north- wheeler bound eighteen wheeler? Big switch Turn off CB set I'm going to pull the big switch. Eights Goodbye (from amateur Threes and eights to you. (eighty- radio 88's meaning Big 10 -4 Acknowledged with That's a big 10 -4. eights "love and kisses. ") enthusiasm Eyeball Face -to -face meeting Can we get together for Bleeding Interference from a A local (station) is an eyeball? nearby CB channel bleeding all over you.

Feed bears Pay a fine for speeding I can't afford to feed any Break I'd like to interrupt Break, break. to highway patrol bears. Breaker One who interrupts Go ahead, breaker. Final Last transmission I'll turn it over to you for Catch Talk to We'll catch you later. your final. Chicken Weigh station for trucks The chicken coop is Flip flop Trucker's return trip We'll catch you on the flip coop closed. flop. Clear Out, final transmission We're clear Four wheeler Automobile You've got a southbound four wheeler.

JANUARY 1976 91

www.americanradiohistory.com TERM MEANING TYPICAL USE TERM MEANING TYPICAL USE

Getting out Being heard Just wanted to see if I Over Behind If you're at the truck was getting out. shoulder stop I'm over your Good buddy Salutation used by What's the smokey shoulder. truckers situation, good buddy? Peanut Not listening to CB set Guess he's got peanut Gone Final transmission, or We're gone. butter butter in his ears. going to switch to in ears another channel? Putting on Strength of signal What kind of a signal am

I putting on you? Green Money paid in fines for I'll back her down.

stamps for traffic violations I don't have any Radio check Reception Give me a radio more green stamps. check, please.

Hammer Truck's accelerator There aren't any Read Hear I read you loud and smokies ahead so let clear. the old hammer down. Rig CB set What kind of a rig Handle Operator's assumed The handle here are you using? name is "Bikini Watcher." Roger I acknowledge Roger on that. High gear Use of transmitter See if my signal Scatterstick Vertical antenna with I'm using a scatterstick power amplifier changes when I shift ground plane at the moment. into high gear. Seventy -three Best regards (amateur Seventy- threes and hope Holler Call I gave you a holler, but radio term to catch you later. you didn't come back. Shout Call Thanks for the shout. Home twenty At home I'm at my home twenty right now. Ski, short Atmospheric conditions Sorry. Those short skip that permit contacts skip stations have How about? Calling How about that "Bikini greater than line -of- you covered up. Watcher" one time? sight distances. Landline Telephone call I'll give him a landline Smokey -the- Highway patrol troopers A smokey is on the move, and pass the info. Bear, smokies heading east. Lay an See Can you lay an eye SWR Standing wave ratio This antenna gives me a eye on on me yet? two -to -one SWR. Linear Extra power amplifier Are you using a linear Taking pic- Radar operated The smokies are used to increase or are you running tures speed indicator taking pictures. CB transmitter output barefoot? Ten-fou r? Do you understand? Is that a ten -four? Local yokel City police officer There's a local yokel

northbound on the move. Ten roger I acknowledge That's a ten roger. Mail Overheard conversation I've been sitting here Tijuana taxi Police car I've got a Tijuana taxi in reading the mail sight. Mercy. Aah. Pause. Speech Mercy, that's a big Thermos Tanker truck I'm pushing the white habit have no parti- ten -four. bottle thermos bottle. cular meaning Threes Seventy- three, best Threes to you. Mile markers Small signs along The smokey is located at regards interstate highways the 142 mile marker. Throwing Transmitting What kind of a signal am

Mobile CB set mounted in I'm talking from my I throwing at you? a vehicle mobile. Trip Strong signal You're making a fine trip

Modulate To talk with I think I modulated with down here. you last week. Twenty Ten -twenty, location What's your twenty?

Move In motion That smokey is on the Walked all Overpower by a stronger Come again. Somebody move. over signal just walked all Negative No That's a negative. over you. Negative station being called Negative contact. Wallpaper Postcard acknowledging Give me your twenty contact failed to respond I'm gone. a two way contact and I'll send you some wallpaper Negative Did not hear response Negative copy. We're by. copy by the station called Wall -to -wall Loud and clear I'm hearing you

wal I -to -wall. Negatory No, negative Ne -ga -tory (said slowly for added emphasis). Wrapper Paint job on car That northbound smokey is in a plain One time For a short contact Calling that "Bikini white wrapper. Watcher" one time. XYL Ex -young lady, wife How's your XYL? On the side Standing by (listening) We'll be on the side.

on the channel YL Young lady I met your YL at the last eyeball.

92 POPULAR ELECTRONICS

www.americanradiohistory.com expansion at higher levels of brightness. At low levels, the raster lost its blooming quality and filled the screen

properly. "Is that the trouble ?" I asked. "The picture is blooming Art's TV Shop somewhat. It's supposed to stay the same size at all brightness levels. He pulled out the instruction manual and examined it. "Yeah, you're right. That's the trouble. It's blooming, By Art Margolis but that's not what I meant." I looked at him quizzically. He went THE BEWILDERING BRIGHTNESS on, "I was doing Experiment 9. When I got to the BRIGHTNESS LIMITER JONATHAN, my next door neighbor, He was supplementing the course adjustment, my results didn't agree was waiting in my driveway with my advice, usually before dinner. with the manual."

as I pulled up in the service van after a He said, excitedly, The TV came "Run through it again," I said.

busy day at the shop. I honked to my from the school today. It's a honey!" I He nodded and began the num- wife to start dinner. Lea looked out the looked it over. It was the 19FC45 chas- bered sequence. First he pulled the window, saw Jonathan and nodded sis. I had installed and worked on quite cheater out. Then he disconnected the

knowingly. I was going to have to help a few of them recently. i -f cable from the i -f strip, and attached

him out again before I ate. His voice saddened, "I began the his voltmeter across a 3 -watt resistor

Jonathan blurted as I stepped out of checkout and I must be doing some- near the flyback. He plugged in the

the truck, "Art, I want to show you thing wrong -it doesn't do what the cheater again and the receiver came

something. It will only take a minute." I book says it should." alive. "Watch this," he said turning the

smiled, but my stomach was growling. "Let's take a fast look," I said, trying BRIGHTNESS LIMITER control. The

I followed him into his basement to console him. I plugged in the chea- meter needle held still. "The voltage is where he had set up his workbench. ter cord. The sound came on, and the supposed to vary," he moaned, and On the table was a new modular Zenith high -voltage circuits crackled to life. be set at 1.7 volts." TV with the back off. Its shipping car- The raster's brightness gradually in- My stomach was snarling for food,

ton lay nearby. Jonathan is an accoun- creased. I noticed there was a slight but I couldn't resist the puzzle. I took

tant, but he enrolled in a home -study bloom to the picture so I adjusted the the instruction manual and opened to TV service course as a leisure pursuit. brightness control. There was definite the foldout schematic (Fig. 1).

TO VERT OUTPUT 4 F203

R231 _35V TO BRIGHTNESS LIMITER FROM 0705 VERT LIEF AMP S6K 4-- IW R203 W HT 4.7 C242 5x111/ WHT/vl0 39 75V 1R 205 390 15 12 BLU YEL 0 0<, YOKE AND PINCUSHION 14 II i ZDO O (LEAD IN VIEW) WHT/YEL 13 IO Q O 1O J204

--*TO ELK CONVERGENCE _[i 207 - RED - FOCUS B CABLE CONTROL SOCKET r GRN T206 (LEAD IN VIEW) 1 29.6.tI KV (19EC451 R237 J203 27.6IKV(17EC45) 14r RED H.V.OUT ISMEG 290f1 4 RED /WHTf R232 N BLEEDERI 820 f - l YEL 3W O H.V O- TO *29 TRIPLERBL CR214 CHROMA _ _J il-TAC TORY SELECTED VALUE F01:71 EOARDt- BLEEDER CONTINIUED COMPLIANCE WITH - - -'J1 GRU R228 RADIATION SAFETY LOW REPLACE - FACTORY RED SELECTED 200 WITH EXACT TYPE ONLY. 3W I FOC US LEAD FROM C232 VALUE L206 00 PF R230 TO 500 ? FOCUS GRID HOR1Z 1 1 C234 fi236 L-aw C229 6KVV3SS ?18 CR211 .0018 C2401 L218 DRIVER 600PF .b KV 2R2C 16KV .0018 047 1R234 2 0 K IsxI5x 1.6KVI S% CR213 50 I C231 - Ì- 5% ( PART OF rCR2I6 1 BLU - -1204 600PF - SWEEP) 2KV III BRIGHTNESS l YEL - 910K -C235 t LIMITER B70V 19EC45 92!? I 5% CO237 .0018 -ÓÓI I.6 KV +130V R236 1.6KV WHT 10 2KV 5% RED r BL K Q202 I17EC45 R224 - 600PF R222 -I C2 27 121- 831 2 KV 800 i zW ?óV FROM 5W +l HORIZ.OUTPUT C245 R227 .I MFD J W HORIZ +130v DRIVER TO SAWTOOTH SHAPER 4 -- Fig. 1. Brightness limiter controls.

JANUARY 1976 93

www.americanradiohistory.com TO BRIGHTNESS CONTROL 4

VERT BLANKING SIG

R915 9 0903 v CR902 470 -88 Q N1 W3 ( LOW LEVEL 0901 121- 695 R912 LUMINANCE 121-433 BLANKING IK 1.7 DRIVER R 99299 I MODULE VERT. 1C 90 BLKR. L 50 ¡ 39050PF w U12 5y 14 N1A I F---, R901 C902 22K V 0?^ R917 C901 100 .047 R907 R906 R908 0904 330N 6.RK U12 121-744 1 - C908 2ND C9 - 47 1 VIDEO 390P06 F C907 T-9nn, 13 R918 SOV CR901 I 1.3K,1/2W -r. Q905 TO R203 2 WI 121- 699 R204 TO RASTER BLANKING R920 t 10K LUM. BLANKER - W5 E00AK SPACE COMMAND ONLY 172040 II( 14909 IBOOPF = R903 18K kV FROM C I -- >W7 11 L902 15K 0902 R910 58yN RiI4 100 IF--I 121-695 15K C903 2SN.P 6905 8911 U 3.3 K 82 ALL RESISTORS R904 ARE I /4W 5% 270 UNLESS OTHERWISE SPECIFIED. BRIGHTNESS LIMITER

U12 W15 014 U4 T T 24v FROM BRIGHTNESS LIMITER CONTRO 4 FROM CONTRAST CONTROL TO CONTRAST CONTROL 4- CONTRAST CONTROL The 3 -watt, 820-ohm resistor, R232, Fig. 2. Schematic of luminance moduli'. was connected from the bottom of the tertiary flyback winding to ground. The desired voltage drop (1.7 V) occurs when the proper amount of GR TO TO CRT GRIDS 250V CRT RED TO CRT current passes through the flyback A BLUE TO CRT winding. This monitors the amount of 1 beam current. Too much current U6 U8 U10 LI 30 U12 W31 U20 U28 would cause the high voltage to drop, LI, 07 5P61t02 120i 550p4 producing the "blooming" effect. R1259 - -0 o-- -0 o-- 3908 SPG 1203 The BRIGHTNESS LIMITER control is v2W o o connected to the voltage tripler with a R1260 SPG ° 100K W18.OI 1204 zener diode through a 500 -ohm, 1/2W R121 I. R1246 5% 18k 61038 81253 R 23' pr9 R1247 7 0 IRK -watt resistor (R230). This trio picks 2w 208 k IBA 2W 1 R1252 1 5. W 142W 5, w 5% 55. W K 5% off a positive pulse and transmits it 1"W 5. 1/24,5% R12 39 through a 270 -ohm resistor on the R1249 2.7K 1,61253 ,R1230 I 568 2.78 4 I/2W 2.08 I/g w W rl_'IS 5% ÑS+ II I/290,5 ttR1255 LUMINANCE MODULE (Fig. 2) to the base S /. IK 14Pf 1 ' C121 RR4STC1221 12W PIZZI R1232 of the brightness limiter transistor. 9124 113P/ T 568 IBPF 5% I 13K ISk 2.OK v2W 01212 I/2w 1 W 81248 p01 D 5% 5% 1.28 GRN -> 1/2W W1 L1204 5% 6 yN BLUE CR 5TI 1202= C1214 C1213 =100Pí 100Pf 0220 W 100Pí T4 44 01204 I 1237 IS R1254 01205 IK /2 W,5% 1 121 -952 QI206 IK I/R. I W 12I -868 5%14W 121-868 01207 1 VIDEO DRIVER RED VIDEO 121 -868 R1250 R1242 BLUE VIDEO R1234 IRO OUTPUT 9 -89 OUTPUT vzw GREEN VIDEO MODULE OUTPUT I UN ASSY. R1256 L202 SW 201 VIDEO 6°°13E L 2.2 R1-52. OUTPUT 1 /4W 2.2K 130~O 5% 1/4W,5 O NORM CR21 WIT f-o CR21B w31 W IS 31 W3' W19 WS W31 W23 SETUP -.+24V #307 8215 2 2 R206 6 BK GR CHROMA SIG 2.7k IRK 1W 112W 1 /2W BLUE CHROMA SIG 5% 5% RED CHROMA GRN/w8T PORI_. PUI. SE VIDEO TO DELAY LINE FROM OUTPUT OF 0104 Fig. 3. Video output module.

94 POPULAR ELECTRONICS

www.americanradiohistory.com This transistor amplifies and inverts "The prime suspects are thus Q902, He held a little transistor in his palm. the pulse which is then fed to C904, a R904, C904, R919 and R905, in that "Recognize Q902? It was shorted, 47 -µF filter capacitor. The latter order. Right ?" base to collector. The control's work- changes the pulse to a smooth dc vol- "Right," I answered. "I have to eat ing perfectly now. No more bloom- tage, which is fed through the now, so check them out yourself." As I ing!" CONTRAST control to the base of Q904, left with my module caddy, he had his I nodded and cut another piece of the second video amplifier. nose buried in the circuit. steak. He looked annoyed, "Come on The luminance output of Q904 is Dinner was going great when back and I'll show you." coupled to the base of Q1204, the Jonathan burst in the back door. I Meanwhile Lea brought out a tax video driver (Fig. 3) through the DELAY quickly put a hunk of steak in my form she was having trouble with.

LINE (L202). This transistor drives the mouth thinking that I would have to "Jonathan," she started. emitters of the three chroma outputs run back to his basement -the week He held up his hand, "I'm sorry Lea, (Q1205, Q1206, Q1207). before he had fried a power trans- but it will have to wait till later tonight,

When the outputs of the three former! after I eat. chroma stages are low, the CRT cathode voltage goes positive and cuts off the electron beams. If the color outputs are high, the beams flow toward the control grids. In this way, Memory Mania! the level of conduction of transistor Q902 produces the brightness limit- 4K - $ 215! 12K -$ 562! ing. 16 I said to Jonathan, "Bring in my 8K - $ 402! K -$ 696! module caddy." He disappeared, and IT'S ALL DYNAMIC MEMORY! while he was gone, I turned on his scope and connected the probe to the The SPHERE Memory board. Is designed to hold 16K of Memory on one board. in 4K increments to base of Q902. The positive pulse from 2107A -8 memory chips are used on this board and are designed allow choice of 4, 8, 12, or 16K. Eack memory chip is socketed and is delivered to you BRIGHTNESS LIMITER the control completely assembled and tested. The PC memory board connects to the CPU board should have appeared, but there was tri -state buffered bus cables. The memory locations are strap selectable as to order of nothing there. Jonathan returned. addressing. Those memory mania purchasers of 12 or 16K who have, or who buy, any SPHERE Computer System will get absolutely free the SPHERE extended BASIC compiler. I opened the caddy. As luck would All documentations will be included. have it, I didn't have the luminance module. Instead, I pulled out my bun- THE MORE THE MEMORY...THE MERRIER. dle of jumper leads. I've found that working on these modular TV's de- AND...If you're not into computers yet...Look at this: mands a lot of them! microprocessor with 4K dynamic memory. 1 K EPROM Removing the luminance module $622 CPU Board: 8 bit parallel containing program development system or Basic language subset or your specific from its prongs, I attached a jumper application software. Real -Time Clock, bus cable structure and 16 lines of from each connector on the module digital I/O optional. to the module's chassis -mounted $207 CRT Board: generates 64 character ASCII character set which is displayed on 16 (5 x 7 matrix). Electronics will display on television set or connector pins. Then I made sure I lines by 32 characters connected the jumpers to the correct video monitor. numeric and cursor keypad. points. $160 Keyboard: ASCII type alpha /numeric keyboard with Communications Board: includes FSK Modem (110 to 600 baud) originate /answer Since I had no pulse on the Q902 $219 with cassette or telephone interface includes serial I/O capabilities (110 to 9600 input, I disconnected the jumper from baud) it is EIA, TTL, TTY, current loop I/O and RS 232 compatible. complete inter- the U8 connector pin. Then I turned on $160 PIM: Peripheral Interface module, 64 digital I/O board allowing the receiver, and touched the probe to facing with printer and Floppy Disks Systems. volts 5 amps, 12 volts at 3 amps, -5 volts at 400ma, the BRIGHTNESS LIMITER control wiper. $96 Power Supply: produces 5 at The pulse was there! The scope indi- -12 volts at 400ma. Or...you can buy the combination of the above assembled in an attractive chassis with line its 2 V cated that amplitude was about printer and /or Floppy Disks starting at $1400 for assembled systems, while kits start at (p -p) as it should be. $860! That meant the flyback circuit was Check with us on our options too, from Light Pens, to Color and B/W graphics terminal, line printers, Disks etc. good. As a double check, I recon- nected the jumper. The pulse was gone again! Something in the luminance module was killing the pulse.

I explained to Jonathan what I had discovered, who was quickly jotting down notes. He had been watching the technique with the jumper cables carefully, and now knew that trick of the trade. He examined the schematic care- SPHERE

fully. I recognized something of my CORPORATION 791 South 500 West Dept. 128 (801) 292 -8466 way of doing things as he intoned, Bountiful, Utah 84010

JANUARY 1976 CIRCLE NO. 54 ON FREE INFORMATION CARD 95

www.americanradiohistory.com the original glow disappears and is replaced by a fainter afterglow that per- sists for many seconds. A discernible image will remain on the tube for Amateur about two minutes.

Equipment Requirements. To get Radio started in SSTV, you'll first need a receiver capable of receiving SSB signals (usually no problem) and an SSTV monitor. This can be a commercial, By Herbert S. Brier ready -to- operate unit (there are sev- SLOW -SCAN TELEVISION eral on the market), or a home -brewed unit. If you replace the P1- or P4- phosphor CRT in an oscilloscope, you'll have the nucleus of a monitor. A THE DREAM of long- distance receiver, which are locked in step with converter that processes the audio amateur video communication those in the camera by sync pulses. output of the receiver into a form usa- was made practical by Copthorne Although the beam does not stay at ble with the scope can be fairly easily MacDonald's article "A New Narrow any one part of the picture screen for built. Image Transmission System" in QST more than a small fraction of a mil- Something new on the slow -scan (August and September 1958). "Cop" lisecond, the compound's lasting scene are scan converters, which use developed a system of transmitting TV phosphorescence or "persistence," A/D and D/A converters, digital signals requiring the same bandwidth together with the response of the memories and shift registers to gener- as an ordinary SSB voice signal, open- human eye, enables us to see an ate a picture compatible with a stan- ing up the possibility of DX TV work on "even" picture. dard home TV receiver. They are gen- the hf amateur bands. As a result, you Slow -scan cameras and picture erally available with raw video and /or can now tune around the bands and tubes act in much the same way, but at modulated (Ch. 2 or 3) r -f outputs. hear a number of raspy "slow- scan" a much more relaxed pace. In this They also allow the use of fast -scan (SSTV) signals, especially around scheme, an image is scanned from top surplus closed- circuit cameras in your 3.84, 7.22, and 14.23 MHz. to bottom in eight seconds! Also, it is SSTV pursuits. Although the units are broken down into only 120 lines, and fairly expensive, they will be attractive Slow Scan Vs Fast Scan. Predict- the repetition rate is seven frames per to many newcomers to SSTV because ably, the fundamental difference be- minute. the cost of a special slow -scan tween conventional fast -scan and As the bandwidth of an information monitor is eliminated. Coupled with slow -scan TV lies in the rates at which channel is directly proportional to home TV receivers, these converters their pictures are "taken" and "de- how many bits are handled in one time can produce higher -quality images veloped." A fast -scan camera splits unit, SSTV signals take up a tiny slice than those on conventional slow -scan the incident image into 525 narrow of the spectrum when compared to monitors. Further, they usually have horizontal lines, scans them all in fast -scan channels (6 MHz each). In "freeze" modes which will store 1 /30th of a second, and repeats the fact, the "bit rate" (the rate at which and /or display a received picture as entire procedure 30 times a second. units of information are sent) is so long as power is applied. The position of the scan point is con- slow that it's practically impossible to To transmit slow -scan images, you trolled by the horizontal and vertical send it by conventional AM. "Cop" will need a video sensor, a modem, sweep circuits within the camera. The elegantly solved the problem by fre- and an SSB transmitter. The sensor varying amount of light reflected from quency modulating an audio subcar- may either be a vidicon coupled with the televised object causes the photo - rier, which in turn "amplitude mod- an electromechanical shutter device, sensor in the camera tube to generate ulates" the transmitter. As shown in or a flying spot scanner (the less ex- a proportional voltage signal. Fig. 1, the standard subcarrier fre- pensive approach). The modem con- This signal modulates (usually AM) quency is 1200 Hz. Black is at 1500 Hz, verts the video and sync information the carrier, and is recovered by the and 2300 Hz represents white. Sync into audio tones which modulate the video detector in the TV receiver. It is pulses appear between 1200 and 1500 transmitter. If you're lucky enough to then used to control the intensity of Hz (blacker than black), thus they do have a scan converter, a standard Vid- the electron beam striking the phos- not appear in the received picture. icon or CCD camera can be used. For phors on the picture tube's face. At the Only 1100 Hz of bandwidth is required! more information, consult the sources same time, the position of the beam is Due to their short "persistence," listed in the box. controlled by the sweep circuits in the fast -scan cameras and picture tubes What's happening on SSTV? Hun-

SYNC "BLACK" "GRAYS" "WHITE" can not be used in SSTV work. The dreds of U.S. and Canadian operators illuminated portions at the left of one are working each other and the world line would fade before those on the regularly near 14.23 MHz. Don, right were "developed." Conse- W9NTP, recently returned from a long quently, a longer lasting "glow" is trip on which he carried SSTV gear. He

1200 H. 1600 Hz 230OHz needed, which is accomplished by a worked many U.S. amateurs from Eas- 1100 Hz CRT with a P7 phosphor. When P7 is ter Island and other exotic points. Fig. 1. Frequencies of audio tones struck by an electron beam, it glows Barry Goldwater, K7UGA, on his trip to determine shading on SSTV picture. brightly. But as the beam moves on, Southeast Asia, plugged SSTV 96 POPULAR ELECTRONICS

www.americanradiohistory.com tween 0100 GMT, January 31, and SSTV INFORMATION SOURCES: 2359 GMT, February 8. Operating a maximum of 30 hours during this -Slow -Scan Television Handbook," by Don Miller, W9NTP, and Ralph Tag- period. Novices work everyone, and gart. W8DQT. $3.00, 73 Inc., Peter- other amateurs work only Novices. borough, NH 03458. U.S. and Canadian stations exchange 'Specialized Communications Tech- RST and their ARRL sections. Others niques for the Radio Amateur." $3.00, substitute country for section. A com- ARRL, 225 Main St., Newington, CT plete two -way exchange earns one 06111 point. Total score equals the number Robot Research, Inc., 7591 Convoy Ct., of contact points (after duplicates are San Diego, CA 92111. deleted!) plus the highest speed Summer Electronics & Engineering Co.. shown on the contestant's ARRL Box 572. Hendersonville. TN 37075. Code- Proficiency certificate multi- Venus Scientific. Inc., 399 Smith St., Farmingdale. NY 11735 plied by the number of sections and other countries worked. Complete rules and score sheets are available equipment into existing SSB rigs and from ARRL, 225 Main St., Newington, T348 O was quite active for a while. CT 05111, on request accompanied by n a stamped. self- addressed envelope. License Requirements. One po- Instruments, tential roadblock to getting started in Amateur License Courses. The SSTV below 28.5 MHz is the necessity Indianapolis American Red Cross of having an Advanced or Extra Class Amateur Radio Club, 10th and Central Burglar Alarms, license. This is one more reason to Aves., Indianapolis, IN, will sponsor a upgrade! Generals can use SSTV General Class license course starting Automotive & above 28.5 MHz. and Tech's can en- January 12, 1976. The course will be gage in this type of work on their held every Monday between 7:30 and phone frequencies above 50 MHz. 10:00 p.m. Everyone 16 years or older Hobby There is quite a contingent of or who holds a Novice license is eligi- SSTV'ers on 114 and 220 MHz in the ble for the course. Instructor is John Los Angeles area. Jacobs, Jr., WB9KSZ, assisted by Incidently, because SSTV modulat- Robert Foot. K9KGJ. The LREC The more you know about ing signals are actually audio tones, Amateur Radio Club. 2814 Empire pictures can be recorded on an ordi- Ave., Burbank, CA 91504, also starts electronics, the more you'll nary tape or cassette recorder. its new General Class course, January appreciate EICO. We have a wide 12, after the conclusion of its last range of products for you to Novice Roundup. The 1976 ARRL Novice session. Bill Welsh. W6DDB, is choose from, each designed to Novice Roundup" will occur be- the instructor. Q provide you with the most pleasure and quality performance for your money. The fact that more than 3 million EICO products are in use attests to their quality Imagine a curriculum in Electronics Technology that includes field trips to the Bahamas and and performance. the Florida Keys. Florida Institute of Technology offers you this and more. Our fully-accredited two year Associate of Science degree program in "Build-it-Yourself" and save Electronics Technology provides a unique balance between the academic and the practical. up to 50% with our famous This course offers specialization options in Marine. Communications. or Industrial technology. electronic kits. Our coeducational campus is set in 84 acres of the Indian River at tropical palms bordering For latest EICO Catalog on Test Jensen Beach. Florida. For further information return coupon to Instruments, Automotive and Hobby Florida Institute of Technology Electronics, Eicocraft Project kits, 720 S. Indian River Drive. Jensen Beach. Fla. 33457 Burglar -Fire Alarm Systems and name of nearest EICO Distributor, check reader t-- Nane service card or send 50e for fast first class mail service. Street EICO -283 Malta Street, City Zip Age_ Brooklyn, N.Y. 11207 veteran l'E 1 R, Leadership in creative electronics since 1945.

JANUARY 1976 CIRCLE NO IS ON FREE INFORMATION CARO 97

www.americanradiohistory.com The $300 Hobby alternative. Let us know 8 weeks in advance so that you won't Scene/ miss a single issue of POPULAR ELECTRONICS. Attach old label where indicated and print new address in space provided. Also include your mailing label whenever you write concerning your subscription. It helps us serve you promptly. 5qß Write to: P.O. Box 2774, Boulder, CO 80302, giving the following information: Change address only. By John McVeigh Extend subscription. Enter new subscription. 1 year $6.98 Payment enclosed (1 extra BONUS issue) Bill me later WINDSHIELD -WASHER ALARM AFFIX LABELS co Q. Is there a circuit which will let me r. .,. i ó know when the windshield washer v fluid in my is running low? N car ú d oá -R. Claudet, Tannersville, NY v isR tret mm IC= 16 m m M A. This circuit will do the job. Insert -J the two metal probes (pin plugs, stiff bare wire, etc.) into the washer fluid s ñ +12V S ó SAE MARK XVII A

Dual -Channel Equalizer 10K 10011 2W II DI D2 HEP S9100 2

re I t' Your tone controls are just not designed to compensate for acoustics Room a Speaker placement If_ d Add'I postage per year Add $1 for Canada; $2 for all Old or had recordings other countries outside the U.S. We built the Mark XVII Equalizer to PROBES solve these problems and more. r 7 These are some of the ways: reservoir, leaving tips about 1 inch (2.5 Individual Octave Control for each cm) above the bottom. Install indica- WHAT'S HAPPENING channel tor I1 (which can be a 53 pilot bulb, a Long throw, oil- damped linear Sonalert or a buzzer) at a convenient TONIGHT? slide pots for greater accuracy viewing angle. When the fluid level ElDual range operation (controls drops below the probe tips, the lamp operate over either ±8dB or +16dB) will light. Diodes D1 and D2 can be common 1 -A power supply rectifiers. Plus The alarm will work with water and Capable of driving any system most detergent solutions. Low distortion-less than 0.03% THD and IM Low noise -greater than 90dB DOUBLE -SIDED PC BOARD BLANKS 05 -year parts and labor service Q. I have been unable to find a contract source for double -sided pc board now $132.50 SAE'S reputation as the finest blanks. Any ideas? IV. The ultimate scanning manufacturer in the audio field The BEARCAT -David Greenwood, Allison Park, PA monitor. Hear any eight channels of action, excitement and information from the na- You'd have to look a long time to A. There are a number of sources tion's four public service frequency bands! find an EQ that delivers this much which cater to the hobbyist. Two that value. SAE innovation has done it. we know of offhand are: r 1 Bearcat (Vs Comíxmi ntsfortheconnoisseur. Techniques, Inc. Please send me 0 $132.50 ea. 235 Jackson St. Please send me __ Crystal Certificates Englewood, NJ 07631 re $3.25 ea. (Minimum order $10.00.) GC Electronics (Calectro) Send check or money order to: Scientific Audio Electronics, Inc. PE -1 -76 400 S. Wyman St. P.O. Box 60271, Terminal Annex Rockford, IL 61101 BETA ELECTRONICS Los Angeles, California 90060 P.O. BOX 5869 Please send me the reasons (including available liter- (or through local Calectro dealers). ature) why the SAE MARK XVII Dual- Channel PITTSBURGH, PA 15209 Equalizer is the S300 Alternative."" This is by no means an exhaustive list. NAME Check with electronics stores in your Name in ADDRESS area, and scan the ads Electronics Address Market Place each month in this CITY STATE ZIP City State Zip magazine. L .11 CIRCLE NO. 48 ON FREE INFORMATION CARD 98 POPULAR ELECTRONICS

www.americanradiohistory.com INTRODUCING HALL EFFECT AUTOMOTIVEN ELECTRONIC IGNITION Transmits maximum available voltage no matter how weak the battery.

Every electronic ignition system today claims the fifth, and newest, generation in electronic advantages over the traditional Kettering contact ignition. A solid -state Hall Device, replacing the

point set for firing spark plugs. The Voltronix System point set and condenser, fires at less than 1 RPM has been proven in over 750,000 road and test track no matter how weak the battery. Only four majór miles. There is no mechanical or electrical wear: components make up the system, and the entire gasoline mileage is increased because the ignition conversion can be made in less than 30 minutes: Electronics Library system stays constantly in tune; spark plug life is (1) Control Unit, (2) Fully terminated quick- connect extended up to 50,000 miles: the ignition system Wire Harness, (3) Metal Signal Chopper, (4) Hall becomes virtually maintenance -free. Most elec- Device firing signal generator. tronic ignition systems are 'rate- sensitive ", that is, The signal generator mounts in place of the during starting, they must attain a high rate of RPM point set. It consists of a permanent magnet and the BASICS OF ELECTRICITY AND ELECTRONICS before sufficient voltage reaches the spark plugs. Hall Device. Each time a metal Signal Chopper blade by Matthew Mandl Therefore, a weak battery poses starting problems. passes the magnet, the Hall Device senses a change This revised work (formerly Fundamentals Not so with the new Voltronix Hall Effect system, in the magnetic field, electronically triggering release of the spark. of Electric and Electronic Circuits) pro- Technical Specifications: vides updated coverage of electronic -40° to +300 °F Negative ground theory, related equations, symbols, ab- 0 -100% humidity Full reverse polarity breviations, and associated data. Chapters protection are devoted to atoms and electrons; basic 1 RPM to 7,000 + RPM Permanent dwell setting electrical units; series and parallel circuits; 4.5 to 16 volts input No tach adapter principles of magnetism; dc and ac meas- required urements; RLC (simple and complex) cir- 27,000 volts output Compatible with all cuits; resonance; transformers and cou- w /stock coil test equipment pling; polyphase ac and pulse- shaping cir- Voltrunix Electronic Ignition conversion. For those knowledgeable in electronics who demand the finest. cuits; and an introduction to tube and Fully guaranteed for 1 year. Fits most 1959 -74 cars. Use your Master Charge. American Express, check solid -state electronics. Many illustrations, or money order. Specify year, make and cubic inch displacement. ONLY $49.95 examples, and problems are included. - - Not VOLTRONIX, Box 116, Syracuse, New York 13205. moi r - Published -Hall, Inc., TO: by Prentice En- SHIP Payment Money 849.95 each Check glewood Cliffs, NJ 07632. 388 pages. Name enclosed Order (includes postage) I N.Y. State Residents add Sales Tax $15.95 hard cover. Address ' Master Expiration City State: Zip- Charge ä date. TELEVISION TROUBLESHOOTING , Cubic Inch American Expiration by Clyde N. Herrick Year Make Displacement Express 7.. date is NE--- MINN-lI IIM State -of- the -art television servicing pre- ,at--- NO 62 ON FREE INFORMATION CARD ------CIRCLE . sented here for those with a basic knowledge of radio theory and basic servicing procedures. General principles of circuit function (and malfunction) are stressed NOW -ALL IN ONE throughout. In the area of chassis analysis, TACHOMETER / CALCULATOR / FREQUENCY COUNTER component identification, and circuit tracing, the illustrations supplementing the text facilitate an understanding of the sub- * RESOLUTION to 1 RPM ject matter. Specifics of circuit behavior, with examples from commercial products, * CALCULATOR + MEMORY illustrate the practical troubleshooting methods required. Test and measurement Model 26A * 1 - 120 KHz COUNTER techniques are explained and illustrated ('/2 second gate time) for each subdivision of troubleshooting methodology. * OPTICAL INPUT Published by Reston Publishing Co., Box (Airplanes, boats) 13995 547, Reston, VA 22090. 230 pages. $14.95 hard cover. * ELECTRICAL INPUT (Automobiles, audio) NORTH AMERICAN RADIO -TV STATION GUIDE TACHOMETER: 60- 7,200.000 RPM. (TENTH EDITION) Resolution to 1 RPM, .01 %. Reads by Vane Jones correct RPM for any number of pulses per revolution. CALTACH PRODUCTS Div. Nearly 10,000 stations (all the active radio CALCULATOR: 5 functions + memory and TV broadcasters in the US, Canada, American Video Corporation 8 digits Mexico, and the West Indies, according to P.O.Box 3008 COUNTER: Sample time of less than the publisher) are listed in this volume. Sta- 1/2 second to display 8 digits from 1 Hz Tucson, Az. 85702 to 120,000 Hz. Crystal controlled tions are listed in three ways -by geo- (602) 885 -4261 accuracy of .01 %. graphical location, frequency (or channel), INPUT: Optical probe - Included and call letters. Important statistics, such Price includes postage and insurance. Electrical probe- Optional as power (day and night for AM stations), Include check or money order with POWER: Internal battery pack or antenna heights (for FM stations) and your order. external AC charger /adaptor. Battery We also accept BankAmericard not included. time -sharing with other stations are given. or Master Charge. Network affiliations are noted, as well as Charge customers include your account ACCESSORIES: Electrical probe 20 educational and FM stereo stations. number, expiration date, and sign your - order. 4' probe extension - 8 Published by Howard W. Sams & Co., 4300 Please allow 6 -8 weeks for delivery. AC charger /adaptor- 15 W. 62nd St., Indianapolis, Ind. 46206. 192 pages. $4.95 soft cover.

CIRCLE NO 7 ON FREE INFORMATION CARO JANUARY 1976 99

www.americanradiohistory.com THE 4004 PROFITMETER Operation Assist AUTO ZERO /POLARITY 32 DIGIT MULTIMETER KIT If you need information on outdated or rare equipment -a schematic, parts list, etc.- another reader WITH BRIGHT RED LED DISPLAY might be able to assist. Simply send a postcard to Opera- tion Assist, POPULAR ELECTRONICS. 1 Park Ave.. New York. NY 10016. For those who can help readers, please re- WHEREVER AND WHATEVER THE JOB, spond directly to them. They'll appreciate it (Only those YOU'LL NEED ITS BATTERY items regarding equipment not available from normal sources are published.) OPERATED PORTABILITY AND ITS HIGH ACCURACY: .1% DCV & OHMS, 1% CURRENT AND ACV. Wurlitzer Model 1015 Juke Box, Serial 2344, made in Canada in 1930. Schematic diagram and /or operating manual. Bob Found, 12 -12 9115 -92 Avenue, Fort Sas- 95 +2.95 P &H katchewan, Alberta, Canada TSL 1A6.

ON THE SERVICE BENCH Less test E.H. Scott Model SLR -F 5 -band receiver covering 80 -550 leads & kHz and 1.9 -24.0 MHz. Serial 2238. Schematic and /or serv- 579 ice annual. Raymond Scott, 422 Grafton Ave., San Fran- batterys cisco, CA 94112. Operadio Model NB1325 Battle Announcing Equipment ELECTRONICS (1945). Schematics or any other information. Bob Macias, 4014 4401 NE 15th Way, Ft. Lauderdale, FL 33334. DEPT 1 PO BOX 1005 MERRITT ISLAND, FLA. 32952 Wurlitzer Model 140B Electric Piano. Schematic. Richard Brush, 1965 E. 3375 St.. Salt Lake City, UT 84106. TO ORDER OR FOR INFORMATION Stromberg- Carlson Model 1121, Series 12 receiver. CALL TOLL FREE Schematic and speaker coil impedances, and any other information. Edward Heimbach. RD 5, Box 169, Strouds- burg, PA 18360. IN THE FIELD 800 - 327 - 2084 De Vry Tech. Inst. ScopeNTVM in same cabinet, model no. unknown. Need schematic, parts list. and power SPECIAL OFFER: "PROFIT" AND SAVE $40,00 transformer. Alan Getz, 148 Camden Ave., S. Plainfield, NJ 07080.

NOW, BUY THE PROFITMETER AND GET OUR RALLY IV STOPWATCH De Vry Projector Model 439. Manual and parts. Fabian Bourge, Box 626, Vinton, LA 70668. KIT FOR $29095 OR OUR LED-10R DD12/24 (HR/MN/SEC/DATE) Lafayette Model HA -230 four-band receiver. Schematic and alignment information. Jim Wilkins, 6215 Lone Oak Dr.. Bethesda, MD 20034. DIGITAL WRISTWATCH KIT FOR ONLY $9,95 WITH THIS AD. Superior Instruments Model 450 Tube Tester. Schematic. S W Hawkinson, 6106 Lillywood Ln., Knoxville, TN 37921.

Weston Tubechecker Model 798 Type 5B. Schematic. Tracy LaVere, 13902 La Pat #16. Westminister, CA 92683. catalog . A jialvr Advalrce. . Hammarlund HQ 145A receiver. Schematic. John Nelms, 521 Parkview, Richardson. TX 75080.

General Electric Model W300B portable intercom. Schematic. Gary Jackson, 1514 So. Ferdinand, Seattle, unique tools, 500)18 R. Rate Rf WA 98108. handy kits, sl Hiatt eï'_: unit. precision 71000: Ameco Model SNLT noise limiter and squelch Schematic. Charles Cerami, 66 Olympic Terrace, Irving- instruments, Progra' ton, NJ 07111. Dural `. technical High , Zenith Model 5808 cabinet "Long Distance Radio" Serial supplies. Arc Cur No. S576805. RCA Model K 80 cabinet radio. Schematics Dave Faverty, 177 Haven -Fast RI '. and any helpful information. Road, Elmhurst, IL 60126.

Sun Model SS -1 Auto Timing Unit. Service manual. Don Parkway, Escondido, CA 92025. *INSURES PROPER COMBUSTION Brown, 216 West Vally *EASIER STARTING Precise Development Corp. Model 300 Oscilloscope. *LONGER POINTS and PLUG LIFE Schematic, operations, and calibration data. Bert Good- *INCREASE MILEAGE up to 40% rich. 886 Juniper Ave., Sherwood Park. Alberta, Canada T8A 2C7. *EASY INSTALLATION (12v neg. gnd.) Our 23rd year of service to the World's Chicago Tube and Set Tester Model 532 by Chicago In- Labtronics' Multiple Restrike (M -R) Ignition finest craftsmen and technicians. dustrial Instruments Co. Instruction manual. Terrie Frane, producesa high energy repetitive spark on each Box 111, Owen, WI 54460. power stroke to effectively ignite the air /fuel Friden Flexowriter Model F10. Schematic and /or remote A carefully selected and tested assortment insures more com- mixture. M -R statistically control jack connections. J. Marcomm, Box 82. Brice, OH of unique, hard -to-find tools, clever plete combustion - resulting in greater energy 43109. gadgets, precision instruments, bargain and increased efficiency. Send for Labtronics' National Model NC 77X general coverage receiver with kits. One -stop shopping for the technician, free literature on the M -R system. Better yet, hobbyist, lab specialist, chassis marks 64 4838 and 64 0946. Schematic and /or craftsman, experience M -R and enjoy the pleasure and service information. Richard H. James, Box 5289 T.E., tools and production supervisor. Many the economy of a well -performing engine. Bradenton, FL 33507. measuring instruments available nowhere and complete Montgomery Ward Airline receiver, TRF circuit, tubes: 3 else. One of the most unusual 1 Year Model VI 579.95 Warranty 1 copy of No 24A 1 No. 27A, 2 No 45. No. 80. Need schematic and tool catalogs anywhere. Get your =Model VI-B 559.95 model no. Charles D. Prater, Edna, KY 41419. the NC FLASHER today. Brochure 30 Day Money Collins Model 17L -8A aircraft transmitter, serial no. 2344. PP.D. in U S A Back Guarantee Maintenance and operations manual. David Moody, 4305 National Camera Send Check or Money Order to: South St., Terre Haute, IN 47802. 2000 West Union Ave., Dept. GGA Labtronics, Incorporated Englewood, Colorado 80110 3635 Hillside, Ypsilanti, Michigan 48197 Aiwa tape recorder Model TP -730. Need motor or source V for same. John Holevac, 301 W. Lead St.. Bessemer, MI (303) 789-1893 DEDICATED TO EFFICIENCY 49911. CARD CIRCLE NO. 36 ON FREE INFORMATION CARO CIRCLE NO. 30 ON FREE INFORMATION 100 POPULAR ELECTRONICS

www.americanradiohistory.com Experimenter 's Corner

By Forrest M. Mims USING AN OPTOISOLATOR

OPTOISOLATORS are ideal for the light source and a silicon detector. solving many noise and high - The latter can be a photodiode, light - voltage isolation problems in elec- activated SCR (LASCR), photosensi- tronic circuits. Until fairly recently, tive FET, photo -Darlington, or, most their prices have been rather high for commonly, a phototransistor. The experimenter use. But now some real housing for the two elements that bargains are available from a number make up the optoisolator is usually a of electronic parts dealers, such as semiconductor package, with the those who advertise in the back of this common IC DIP configuration pre- magazine. dominating. An optoisolator is a relatively simple device, consisting of a light source t9v and a light sensor housed in a light -

tight package in such a manner that ScanTM their active elements face each other. Mini - While the source is always electrically is the pocket isolated from the (in the low JZ sensor OUTPUT scanner that kilovolt range), the two are optically works a week coupled in such a manner that a signal activating the source will trigger the on just 4 sensor. penlight cells. Most optoisolators use a gallium - arsenide (GaAs) infrared emitter for A breakthrough we call "mini- 1V IN (LEO 5000 miser circuitry" .....+. .. makes it possible Fig. 1. An arrangement r ... and it's for coupling one signal to another with an actually 21/2 to 5 times more efficient than any other pocket optoisolator is shown. at right above. The scope scanner we tested!* Just 4 alkaline photo at right is typical penlight cells power it for a full of input and output week, 8 hours a day, on a tough pulses for the circuit. 50 -50 duty cycle (50% full volume, 50% squelched). And its performance is bred from our experience in iv DUT (Q) public safety two -way radio ... so it also gives you the crispest, clearest messages possible. Just $119.95 with built -in ferrite antenna (batteries, crystals and optional flexible antenna extra.) IM OUTP *Test results gladly supplied on request. VCC - VIED 6.1 - eff jLED VE.6.= i2sV IzzD = SO ..,q Johnson /NPuT fr vcc=Si; R= 7.5-12. ® MINI-SCAN the professional pocket scanner Fig. 2. One way of coupling circuits with an optoisolator. E. F. JOHNSON CO., WASECA, MINNESOTA 56093 IN CANADA: A. C. SIMMONDS & SONS, LTD.

JANUARY 1976 CIRCLE NO. 33 ON FREE INFORMATION CARD 101

www.americanradiohistory.com Simple Couplers. A simple arrangement you can use to isolate an analog or pulsed signal to be coupled from one to is in SAVE! circuit another shown Fig. 1. The circuit can use any photo - MONEY TIME FREIGHT electronics wants transistor optoisolator. (I used a QUALITY STEREO EQUIPMENT Motorola MCT2, but any similar device AT LOWEST PRICES. can be substituted.) The photograph N- YOUR REQUEST FOR QUOTA- TION RETURNED SAME DAY. in Fig. 1 illustrates a pair of typical input and output pulses for the circuit. N, FACTORY SEALED CARTONS - GUARANTEED AND INSURED. I calibrated the 4 -volt, 1 -kHz square - wave output from the scope to pulse À SAVE ON NAME BRANDS LIKE: c the LED in the optoisolator and moni- A.D.C. KLH tored both sides of the MCT2 to obtain A.R. SHURE DYNACO KOSS this photo. Notice that the base of the SONY FISHER DEALERS transistor is not used. This is the case PIONEER with most phototransistor op- AND MORE THAN 50 OTHERS toisolator circuits, even though man- BUY THE MODERN WAY DISTRIBUTORS ufacturers usually make the base BY MAIL FROM available for special applications such and Truck Stops as external biasing. There are dozens of ways to couple WE ADVERTISE optoisolators to RTL and TTL circuits. AND CARRY A typical circuit for this is shown in FAMOUS BRANDS Fig. 2. The various manufacturers who make optoisolators (Texas Instru- OPCNCe ments, Monsanto, Litronix, Fairchild, Department 217S etc.) all include this and many other 12 East Delaware ßREAI

www.americanradiohistory.com Circuit "). Here's how it works. The miniature 8 -ohm speaker at point "X" transistor in the isolator is normally to make the oscillator's tone audible. cut off, but an applied voltage causes a small current to flow through the Parting Comment. So far, we've outboard transistor and the LED. As examined only one particular op- the input voltage increases, the LED toisolator, but there is a wide range of turns on and triggers the isolator's other useful gadgets that include elec- transistor into conduction. The circuit trically isolated emitters and detec- exhibits negative resistance because tors. These source -sensor pairs, as it begins to conduct only above a cer- they are usually called, can be used for tain voltage threshold at the input. limit switches, object detectors, position sensors, reflectance sensors, and

Relaxation Oscillator. It you've many other applications. I haven't ever built a neon -lamp flasher circuit, seen any of these source -sensor pairs you already know that you can make a on the surplus /hobby market yet. 4

Fig. 4. Relaxation oscillator. TATFMENTOF OWNERSHIP, MANAGEMENT AND 74 ACE OF THE et CIRCULATION (Act of August 12. 1970: Section 3685, simple relaxation oscillator by con- 'itle 39, United States Code). I. Title of Publication: Popu- MONTH SPECIALS ar Electronics. 2. Date of filing: October I, 1975. 3. Fre- necting a resistor and capacitor to a uency of issue: Monthly. 3a. Annual subscription price: negative- resistance component. The 6.98. 4. Location of known office of publicatüon: One Park )venue. New York. New York 10016. 5. Location of the circuit in Fig. 4 shows how this is done leadquarters or General Business Offices of the publishers: with the optoelectronic negative - )ne Park Avenue. New York, New York 10016. 6. Names nd addresses of publisher. editor, and managing editor: resistance circuit. Operation begins 'ublisher, Edgar W. Hopper. One Park Avenue, New York, with the capacitor charging flew York. 10(116; Editor. Arthur P. Salsberg, One Park through DUAL POWER SUPPLY KIT )venue. New York, New York. 10016; Managing Editor. the 10 k resistor until the negative - Dual adjustment + 10 to + 16 volts, regulated, 250 ma. ohn R. Riggs, One Park Avenue, New York. New York Each supply, short circuit protected. Board size 3" X 6 ". Ideal 0016. 7. Owner: Ziff -Davis Publishing Company. One Park resistance circuit switches on. At this` for OP AMP and CMO`', projects. This kit a complete, all parts )venue. New York. N.Y. 10016; Ziff Corporation. One are included. point, the capacitor discharges Complete Kit $24.95 'ark Avenue. New York. N.Y. 10016. 8. Known bond - (includes instructions and schematics) olders, mortgagees. and other security holders owning or through the circuit and the system re- Wired & Tested $29.95 olding I percent or more of total amount of bonds, mort- sets to the off state to repeat the cycle. ages or other securities: None. 9. For optional completion y publishers mailing at the regular rates (Section 132.121. For best results, start with the com- s rIillflis.,s.,s.Ir.p.a',4f.o,A;t n.e'ua,n'.iN!él.'6 'octal Sers ice Manual). 39 U.S.C. 3626 pros ides in perti- 'A!''ele:n'.e:eim'le°R$,n,o,e:'.5 ent part: "No person who would have been entitled to mail ponent values specified in Fig. 4. After L1 a tatter under former section 4359 of this title shall mail such you get the circuit working, you can móééé'é'ñ'c°lfwó`pèm hII á tatter at the rates provided under this subsection unless he îles annually with the Postal Service a written request for experiment with different capacitor ASCii COMPUTER KEYBOARDS ermission to mail matter at such rates." These keyboards were manufactured for use on Texas values to change the oscillation range Instrument's n accordance with the provisions of this statute. I hereby line of Silent 700 series data terminals. They are fully encoded with TTL large scale integrated circuits (T.I. equest permission to publication I of the With the I mail the named in Item circuit. values shown, TMS-5000 in 28 pin socket). Additional IC's provide a par- t the reduced postage rates presently authorized by 39 measured a freqency range of about 3 rallel 7 bit, without parity, code plus a strobe signal indicat- J.S.C. 3626. ing "valid" data and six other independent outputs for those Villiam L. Phillips. Assistant Treasurer to 8 kHz with the potentiometer ad- special keys which are not encoded. The keys are reed type with a format similar to typewriter. Internal circuitry provides for 1. Actual no. justed for a resistance of about 5 k. two key rollover and de-bounce. Output is on stan- Average of copies dard 10 pin double readout connector for data and power in- 1 put. And 8 pin double readout connector for six special no copies of single Changing the capacitor's value to pF switch functions. each issue issue caused the freqency range to drop to KB -7 - Clare /Pendar 720731 -1 New $49.95 :xtent and during published nature of preceding between 120 Hz and 1.8 kHz. nearest to ACOUSTIC COUPLER :irculation 12 months filing date You can monitor the operation of This coupler was manufactu ed by Novation, Inc. Tarzana, Cali- ,. Total No. Copies this circuit with a scope connected ac- Printed (Net Press Run) 427,144 428,637 fornia for use in Texas Instrument's model 725 Electronic Data Terminal. ross the LED and/or .a I k resistor in- B. Paid Circulation It is compatible with Bell 103 and 1. Sales through serted between the emitter of the 113 data sets or equivalent. The Dealers and Carriers, coupler operates asynchronously to a Street Vendors and isolator's transistor and ground. The maximum speed of 450 baud in the full-ohalf-duplex Counter Sales 60,534 58,400 mode coupled to waveforms I obtained are shown in a standard telephone handset. Trans- 2. Mail Subscriptions 295,644 298,927 Fig. 5. Alternatively, you can connect a mit freq. is 1270hz for mark and I. Total Paid Circulation 356.178 357,327 1070hz for space. Receive frequency is 2225hz for mark and 2025hz for D. Free Distribution space. Unit required ± 12 VOLTS by Mail, Carrier and + 5 VOLTS for operation. Com- or Other Means plete with schematic & all pertinent Samples. Com- information, fully reconditioned, cal- plimentary, and ibrated, and guaranteed -$59.95. Other Free Copies 6,158 6,465 MEMORY CHIP

:. Total Distribution SN74S201N 256BIT RAM (Sum of C and D) 362.336 363,792 with 3 state output. Plug in replacement for SN74- F. Copies not distributed 200 & SN74S200. 1. Office use. Left Over, $3.95 ea. 10 for $25.00 Unaccounted, Spoiled METER NEW GUARANTEED After Printing 2,465 2,045 EMICO Model 13 01 2. Returns from a edgewise meter. Scale is News Agents 62,343 62,800 marked a 10 relative output. TERMS: We pay postage, un- Mounts in a 3/4 X 1 7/8 rec less otherwise specified. i. Total (Sum of E & F- tangular hole with a press on Include check or money should equal net press clip supplied with the meter. order, no COD. Texas resi dents add 5% sales tax. run shown in A) 427,144 428,637 New $1.95 each 10 for $15.00 I certify that the statements made by me above are correct a nd complete. ELECTRONIC WILLIAM L. PHILLIPS. Assistant Treasurer PARTS Fig. .5. Waveforms for Fig. 4. 3303 Mangum Road Houston, Texas 77018

CIRCLE N0. 25 ON FREE INFORMATION CARD JANUARY 1976 105

www.americanradiohistory.com ELECTRONICS MARKET PLACE

NON -DISPLAY CLASSIFIED: COMMERCIAL RATE: For firms or individuals offering commercial products or services, $2.00 per word (including name and address). Minimum order $30.00. Payment must accompany copy except when ads are placed by accredited advertising agencies. Frequency discount; 5% for 6 months; 10% for 12 months paid in advance. READER RATE: For individuals with a personal item to buy or sell, $1.20 per word (including name and address.)

No minimum! Payment must accompany copy. DISPLAY CLASSIFIED: 1" by 1 column (2 -1/4" wide), $230.00. 2" by 1 column, $460.00. 3" by 1 column, $690.00. Advertiser to supply film positives. For frequency rates, please inquire. GENERAL INFORMATION: First word in all ads set in caps at no extra charge. All copy subject to publisher's approval. All advertisers using Post Office Boxes in their addresses MUST supply publisher with permanent address and telephone number before ad can be run. Advertisements will not be published which advertise or promote the use of devices for the surreptitious interception of communications. Ads are not acknowledged. They will appear in first issue to go to press after closing date. Closing Date: 1st of the 2nd month preceding cover date (for example, March issue closes January 1st. Send order and remittance to POPULAR ELECTRONICS, One Park Avenue. New York, New York 10016, Attention: Hal Cymes. FOR SALE SOUND SYNTHESIZER KITS Surf $12.95. Wind $12.95. CD IGNITIONS, VHF /UHF monitors. crystals. CB radios. Wind Chimes $17.95. Electronic Songbird $6.95. Musical Southland. Box 3591 -B, Baytown, Texas 77520. Accessories. many more. Catalog free. PAIA Electronics. ALPHA /THETA BRAINWAVE biofeedback instruments. FREE! Bargain Catalog - I.C.'s. LED s. readouts. fiber Box J14359. Oklahoma City. OK 73114. Analog instruments from $125; digital processing systems optics, calculators parts & kits, semiconductors, parts. BUGGED ? ?? New locator finds them fast. Write. Clifton. from $225. BioScan. Box 14168 -E. Houston. Texas 77021. Poly Paks. Box 942PE, Lynnfield, Mass. 01940. 11500 -L N.W 7th Avenue_ Miami Ronda 33168. SURPRISE! Build inexpensively, the most Unusual Test GOVERNMENT Surplus Receivers. Transmitters, Instruments. Futuristic Gadgets using Numerical Snooperscopes. Radios, Parts, Picture Catalog 25 cents. DISCOUNT PRICES Readouts! Catalogue Free! GBS. Box 100A, Green Bank. Meshna. Nahant. Mass. 01908. West Virginia 24944. SENCORE, LEADER, RCA LOWEST Prices Electronic Parts. Confidential Catalog EICO, FLUKE, HICKOK, SIMPSON LEARN DESIGN TECHNIQUES. Electronics Design Free. KNAPP, 3174 8th Ave. S.W., Largo, Fla. 33540. Newsletter. linear projects. design Test Equipment Digital. construction Annual $6.00, ELECTRONIC PARTS. semiconductors, kits. FREE FLYER. ICC Servicemaslei, RCA and Raytheon Tubes theory and procedures. subscription sample Large catalog $1.00 deposit. BIGELOW ELECTRONICS, Complete line of electronic supplies copy $1.00. Valley West. Box 2119 -B. Sunnyvale. California Bluffton, Ohio 45817. Free Catalog 94087. RADIO -T.V. Tubes -36 cents each. Send for free catalog. FORDHAM RADIO SUPPLY CO., INC. TELEPHONES UNLIMITED. equipment. supplies. Catalog Cornell. 4213 University. San Diego. Calif. 92105. 558 Morris Ave.. Bronx. N.Y. 10451 (212) 585 -0330 50 cents, Box 1654E. Costa Mesa. Calif. 92626. AMATEUR SCIENTISTS. Electronics Experimenters. DIGITAL ELECTRONICS! Highly effective course brings Science Fair Students Construction plans--Complete. immediate results. $10.00. Satisfaction or $11.00 refunded! including drawings. schematics. parts list with prices and YOU WILL SAVE BIG MONEY! Surplus. Clearouts. Plans, Projects. Free Literature. DYNASIGN, Box 60A7. 01778. sources Robot Man - Psychedelic shows - Lasers - Bankruptcy. Inventory. Deals, Catalog $1 (redeemable). Wayland. Mass. Emotion /Lie Detector - Touch Tone Dial - Quadraphonic ETCOA Electronics. Box 741, Montreal. H3C 2V2. U.S. UNSCRAMBLERS: Fits any scanner or monitor, easily ad- Adapter - Transistorized Ignition -- Burglar Alarm - Inquiries. justs to all scrambled frequencies. Only 4- square $29.95, Sound Meter over 60 items. Send 50 cents coin (no HEAR POLICE /FIRE Dispatchers! Catalog shows fully guaranteed. Dealer inquiries welcomed. PDO stamps) for complete catalog. Technical Writers Group. exclusive directories of "confidential" channels. receivers. Electronics. Box 841, North Little Rock. Arkansas 72115. Box 5994, University Station. Raleigh. N.C. 27607. Send 10 cent stamp. Communications, Box 56 -PE. SURPRISE! SURPRISE! Digital Piano Tuning Device tunes METERS - Surplus. new used. panel or portable. Send for Commack. N.Y. 11725. musical instruments Accurately! Perfectly! Inexpensively! list. Hanchett. Box 5577. Riverside. CA 92507. CONVERT any television to sensitive, big- screen oscillo- Construction- Instruction -Plans Complete $12.95 Airmailed MECHANICAL, ELECTRONIC devices catalog 10 cents. scope. Only minor changes required, No electronic ex- Postpaid! Moonlighting quickly repays $40 electronics in- Greatest Values - Lowest Prices. Fertik.s. 5249 "D.. perience necessary. Illustrated plans. $2.00. Sanders. vestment! GBS. Box 100P, Green Bank, West Virginia Philadelphia, Pa. 19120. Dept A -33. Box 92102. Houston. Texas 77010 24944. PYROTECHNICAL chemicals, casings. fuse. tools, literature. supplies. Catalog -$1.00. with samples - $2.00. Westech. Logan. Utah 84321. RECONDITIONED Test Equipment. $0,50 for catalog. WORLD'S SMALLEST Walter. 2697 Nickel. San Pablo, CA 94806. FREE giant bargain electronic catalog listing thousands of components, tubes. transistors, IC's. kits, test equipment. EDLIE'S. 2700 -PK Hempstead Tpke.. Levittown. N.Y. 11756. ELECTRONIC ALPHA BRAINWAVE MONITOR New from EICO. Model BW300 Kit. $34.95; Wired. $59.95 Postpaid. Send check or money order. M &K Electronic Corp.. 135 -33 Northern CALCULATOR.$.19.95! Blvd.. Flushing. N Y. 11354.

Does Everything Big Ones Do AUDIO PROGRAM CONTROL CENTER $14.95 PPD. us4 10 inputs, 4 out- Small but mighty! 8- digit, 4- function puts. Switch TV, electronic calculator even has automatic % key ... for only $19.95. Take it any- Short -Wave, Ham, FM to Stereo Ampli- where. Carry it in your pocket or purse it's 2/3 the size of a - pack of cigarettes. fier & Recorder. This 31/2 -ounce dynamo features floating decimal, constant key, lead zero depres- POWERCOM CORPORATION Listen & Record. sion, clear entry, more! At Edmund's low price, the unit comes with a Ni -Cad Box 454 Dept 4 Troy, N. Y. USA 12181 rechargeable battery pack that can plug into any AC outlet. No need for special FOR A New Electronic Experience. learn to control your recharging adapters. Calculator overall is 2 x 31/2 x just °," with plenty of room brainwaves. Aquarius Electronics. Box 96ZE. Albion. CA for most fingers. Another Edmund first advanced 95410. STOCK NO. AVC Only $Í9 GE PPd TEST EQUIPMENT--DISCOUNT PRICES: B &K. Sencore, Leader. EICO. Lectrotech M&K Electronic Corp_. 135 -33 GIANT FREE COMPLETE AND MAIL COUPON NOW Northern Blvd Fluçhing N Y 11154 CATALOG! P -1 EDMUND SCIENTIFIC CO. 300 Edscorp Bldg., Barrington, N. J. 08007 NEW 164Pagr". Citizens Band Over 4,500 Un- Send me: Walt usual Bargains L- ._ELECTRONIC CALCULATORIS) for Hobbyists. SEND FREE DEALER -DISTRIBUTORS 164 PAGE CATALOG "AVC" AVC) $ @ $19.95 ea. (No. 1945 Send this ad with Letterhead to Schools, Industry Charge my BankAmericard Servire and handling JUST CHECK Charge my Master Charge charge $_ 50 PAL ELECTRONICS CO. COUPON! Enclosed is - - PHOENIX, ARIZ. 85017 EDMUND Interbank No I check, m o in amount of $ 2962 W. WELDON 0 Card No YOU SCIENTIFIC CO. Signature BUILD THAT ELECTRONIC ORGAN ALWAYS WANTED AT A PRICE YOU CAN AFFORD Third edition of 300 EDSCORP BUILDING Expiration Date Name "Organ Builder's Guide," pictured product kit line, cir- Please print Barrington, N. J. 08001 I 30 DAY MONEY -BACK GUAR- cuits, block diagrams, design rationale using IC divider Address ANTEE. You must be Satis- and independent generators with diode keying $3.00 post- America's Greatest lied return purchase or any paid. Also. free brochure on keyboards. DEVTRO'JIX Science Optics Hobby Mart n 30 days for full refund City State Zip J ORGAN PRODUCTS, Dept. C. 5872 Amapola Dr.. San Jose, CA 95129. HELPING TO DEVELOP AMERICA'S TECHNOLOGY FOR OVER 30 YEARS.

106 CIRCLE NO. 19 ON FREE INFORMATION CARD POPULAR ELECTRONICS

www.americanradiohistory.com wounommonounommuncommociammunsunerimotominct VERNIER DIAL S. D. SALES CO From a close out of metal detector manufacturer. 1/2 ^3 /L Turn, 8 to 1 ratio. Internal stops easily removed to make a unit multi -turn. 6 Digit Digital Clock Kit LIMITED QUANTITY -1.99 EACH Iwo ws DO YOU NEED A LARGE COMMON ANODE We wanted our word to mean something to you. When READOUT AT A FANTASTIC PRICE ! we first introduced our clock we used such words as S. D. presents the MAN 64 by Monsanto - .40 "impossible ", "unbelievable bargain ", "prime qual- iiii inch character. All LED construction - not re- ity", and "unconditional money back guarantee." We ig flective bar fits 14 pin DIP. Brand new anticipated selling several hundred kits. Your response type, and factory prime. Left D P. to our clock has been fantastic. Now several thousand $1.59 ea. 6 for $7.50 kits later, we hear such comments as "outstanding value ", "exceptional service ", can't believe it etc. "I ", FAIRCHILD LED READOUTS - 69c DRIVER One enthusiastic customer even wrote saying it was FND -70. Common cathode. Right hand 1 TRANSISTORS the best thing since bottled beer." decimal point. .25 inch character. Prime 1 2N3904 - NPN new units. Perfect for clocks, frequency I , 2N3906 - PNP counter s. etc. 69c 10 For $6 I 8 for $1 Here's What The Kit Includes: Best Readout Buy in USA!

1 - MM5314 National Clock Chip with socket 2102 1K RAM's - 8 FOR $12.95 6 - Common Cathode Led Readouts (.25 in. char.) New units by National. We bought a load on a super 13 - NPN and PNP Driver Transistors tt at deal, hence this fantastic price. 2 - Push Button Switches for time set i Units tested for 500N5 Speed. 1 - Switch for Time Hold (KIT) / FET'S BY TEXAS INSTRUMENTS 1 - Filter Cap WITH SPECS. 4 - IN4001 Rectifiers #TIS -75 but with an internal house number. TU -92 Transformer POSTPAID 1 - IN914 Diode plastic case. N Channel, Junction type FET. 2 - .01 Disc. Caps 51.50 SPECIAL 5 FOR $1 9 - Carbon Resistors P.C. BOARD FOR ABOVE FAIRCHILD BIG LED READOUTS 83.00 each A big .50 inch easy to read character. Now available in either common anode or common cathode. Take your INTEL 1702A 2K ERASEABLE PROM'S $6.95 pick. Super low current drain, only 5 MA per segment We tell it like it is. We could have said these were typical. YOUR factory new, but here is the straight scoop. We bought FND - 510 Common Anode CHOICE a load of new computer gear that contained a quantity FND - 503 Common Cathode S2 ea. of 1702A's in sockets. We carefully removed the parts, verified their quality, and are offering them on one heck H.P. IS BACK! of a deal. First come, first served. Satisfaction No Rejects or Retests hero - You Want guaranteed. Duality? You have it with this popular 0.3" L.E.D. by Hewlett Packard. Fits Standard I.C. PROFESSIONAL QUALITY STEREO HEADPHONES Socket. Right hand DP. Here is the kind of super deal that S. D. is famous for. 5082 -7740 - Common Cathode $1.25 Treat your ears to a super sound at a super price. Soft 5082 -7730 - Common Anode $1.25 padded ear cushions, lightweight, fully adjustable e for $6.00 headband, long coiled cord, wide response. S6 Post HEAVY DUTY TRANSFORMER Paid - NEW IN ORIGINAL FACTORY BOXES 36 VAC, 3.5 AMPS. 115VAÇ 60 HZ. LM324 - QUAD 741 OP !.s PRI. For power supplies or audio power AMP - 99c SALE ON CUT LEAD SEMICONDUCTORS amps. Best quality, fully enclosed. $4.95 NE555 - Timers - 49c Leads were cut for PCB insertion. Still very useable. 87978 709CH - OP AMPS - Signetics, TRI -State Hex Buffer. MOS 1N4148 Diode - 40/$1 2N3904 (House #Transistor) - 4 For $1 25/$1 and TTL interface to TRI -State Logic. Special: $1.49. GE SCR C106B1 INSTRUMENT KNOBS 4 AMP 200PIV. Sensi- 936 DTL BY ITT Black with brushed five Gate. 59c aluminum insert. Medium size, very Prime, house numbered. Hex Inverter attractive style. SPECIAL 5 FOR S1 10 For $1 SIGNETICS 1K P -ROM SUBMINIATURE TRIMMER CAPS MOTOROLA POWER DARLINGTON 82S129. 256 X 4. Bipolar, much faster Ultra stable. Range: 3.5 to 18 PF. 2 for $1 $1.99 than MOS devices. 50 NS. Tri -state WA' FILTER CAPS MJ3001 - NPN - 80 Volts - 10 Amps - outputs. TTL compatible. Field program - Dual section, 2000 MFD and 1500 MFD HFE 6000 typ. To -3 Case. Ideal for able, and features on chip address at 30 WVDC Twist Lock. 79c ea. 3 For $2 power supplies, etc. We include a free decoding. Perfect for microprogramming 723 regulator w /schematic for power applications. 16 pin DIP. With specs. NATIONAL VOLTAGE REGULATOR supply with purchase of the MJ3001. $2.95 ea. Like 7805. 5VDC - 1 AMP output. Has You TO -220 plastic power tab - 99c get the two key parts for a DC TEXAS INSTRUMENTS 8 DIGIT supply for only $1.99. Regular catalog IN4148 COMPUTER DIODES CALCULATOR CHIP TMSO 103NC price for the MJ3001 is $3.82 Four function. Same as IN914. Factory prime. 20 for SI Same style as used in TI MOTOROLA NEGATIVE pocket calculators. Factory new units, FULL WAVE BRIDGE VOLTAGE REG with specs. 99c each. By G. I. 1.5 AMP 800PIV - 75c MC1463R - Like our 1469R, except for lAMP 1000 PIV SILICON RECTIFIERS 2N706A 400MHZ. TRANSISTORS negative voltage. Reg. catalog $5. Our IN4007. Factory prime devices. 10 for Silicon NPN. 1 WATT. TO -18 Case. 5 price 51.95. $1.00 For $1 We do not sell junk. Money back 741C OP AMPS LARGE SIZE LED LAMPS guarantee on every item. WE PAY Prime, factory tested and marked. Full Similar to MV5024. Prime factory tested POSTAGE. Orders under $10 add 75c spec on all parameters. Not re- tested, units. We include plastic mounting clips handling. No C.O D. Texas Res. add 5 functional only, units as sold by others. which are very hard to come by. tax. 741 CH -T0-5 8 Lead Metal Can _ 3/$1 Special 5 for $1 741CV - Lead 4/$1 8 Mini Dip MOTOROLA NEG. VOLTAGE REG DL747 JUMBO LED READOUTS MC1469R. TO -66 9 Lead package. For 3 S. D. SALES CO. RAI By Litronix..65 inch character. Common TO 30V Outputs. Provides 600 MA direct P.O. BOX 28810 MI anode. Outperforms SLA -3. perfect for output or more by using an external DALLAS, TEXAS 75228 itgiant digital clocks. Only 20 MA. per power transistor. Reg. catalog $4 ea. segment. Special - $2.50 ea. (Not Class II) With specs. $1.95 ea MERRY CHRI ST MAS AND A HAPPY NEW YEAR ARMIN WREN CARO CIRCLE NO. 49 ON FREE INFORMATION

JANUARY 1976 11)7

www.americanradiohistory.com TELEPHONE "BUGGED "? Countermeasures Brochure Pennsboro, W. VA 26415. $1.00, Negeye, Drawer 547, I WAREHOUSE I SOLID STATE & SAVE ELECTRIC POWER! I DISCOUNTS ON I HOBBY CIRCUITS MANUAL Save up to 80% electrical power with this unique. I NATIONALLY ADVERTISED I $1.95 postpaid to your door. The new inexpensive, portable, permanent and legal method manual offers over 400 pages of cir- applicable for shops, homes, factories, businesses. C.B. RADIOS farms, sites. 100 % Refund Guaranteed if not scien I I cuits for the hobbyist, engineer, experi- tifically sound or if it employs gimmicks. I MONITOR SCANNERS FPZEICE I menter and do- it- yourself kit builder. Information $1.00 IN FACTORY SEALED CARTONS HURRY -Supply limited. Free catalog. CONSUMERTRONICS CO. I I BUSINESS - RECREATION - PERSONAL Frazer & Associates, Dept. PE, 1888 P.O. Box 1399 Alamogordo, N.M. 88310 I SATISFACTION GUARANTEED I Century Park East Suite 10, Century POLICE, Fire monitors, scanners, crystals discount priced. I I City, Calif. 90067. WRITE FOR QUOTE New crystal -less scanners. Box 19224, Denver, CO 80219. I I TELETYPE EQUIPMENT for sale for beginners and exper- ELECTRONICS WAREHOUSE, INC. JAPANESE TRANSISTORS, all transistors original factory ienced computer enthusiast. Teletype machines. parts. 6234 LITTLE RIVER TURNPIKE (DEPT. SI I ALEXANDRIA, VA. 22312 I made. Free catalog. West Pacific Electronics, P.O. Box supplies. Catalogue $1.00 to: ATLANTIC SALES, 3730 OR PHONE: (703) 256 -1300 25837, W. Los Angeles. CA 90025. Nautilus Ave., Brooklyn. NY 11224. Tel: (212) 372 -0349. I I ALTAIR 8800 EXPERIMENTERS - Wirewrap board plugs directly into Altair computer. Includes regulator. heatsink. SERVICE MANUALS for audio equipment. Includes filtering, decoupling, gold edge contacts. Capacity of over schematic, parts list and servicing. Send make, model and BREAKTHROUGH 70 wirewrap sockets (not included). Postpaid $60. $5.00 to Daugherty Audio Service, 7313 Inzer St., Spring- _$ $_ Cromemco. 26655 Laurel. Los Altos. CA 94022. field. VA 22151. - 8080A CPU - $58 - ac Order to ralif.es Een a44 YvfBon 507 JANUARY SPECIALS tttittttttttt64 for rheì4u.va c Il, ca. 95008 DIGITAL CLOCK CHIPS PULTHON V.I.P. QUARTZ REGULATED PC2406A LED Clock Kit. Six Digit. 12/24 7447 S .69 6311 $3.95 LED WATCH MODU- CLOCK. 7483 .59 5312 2.95 hour, XTAL Timebase. Includes Drilled, Plated PC Board 7490 .45 5314 3.95 MEN'S 5 function - hours, minutes, month, and Instructions. Thousands sold nationally! Satisfaction 74151 .59 5316 4.15 day and seconds. Guaranteed! Order Now. 48 Hour Shipping! Only $7.95. 74153 .79 7001 6.95 Latest slim -line design (pro, vs" thick) REL ELECTRONICS, 3511 Lynette Dr.. Amarillo, Texas 74180 ,79 Four year calendar - requires setting only 79109. 74193 .99 CALCULATOR on February 29th. . 9602 .69 One year warranty against all defects in DESCRAMBLERS: Several Professional Models that work CHIPS material and 74000 .12 workmanship. with all Scanners. Tone Encoders /Decoders. Scanmate, 5005 51.69 Built -in phololransistor adjusts intensity of LINEAR display. AAPP, Radar Detectors, Big Ears. Alarms. Books. Kits. 301 mDIP .25 MEMORIES Gold lone - with adjustable mesh strap. parts. Catalog 25 cents: KRYSTAL KITS. Box 445, Benton- 339 DIP 1.29 2102 52.65 ville, Ark. 72712. 320 TO -220 1.39 2101 -1 2.75 4K 8080 COMPUTER, 3 I/O Ports $395 assembled. Kits from 320 10-220 1.39 2102 -2 2.75 $99.50 $35. Details $2.00 (refundable). VACOMP. Box 4733, 340 TO -220 1.39 82523 3.25 +$1.50 Shipping Arlington, Virginia 22204. 340 TO -220 1.39 F93410 2.19 & Handling FUNCTION Usual 10% Discount UNIVERSAL TTL /DTL /CMOS IC TESTER. Tests 16/14 Pin GENERATOR DVM Applies Digital ICs! Set Programming Switches. Plug In: Press To 8038 53.95 5330 514.95 Test: Errors Displayed. 151.072 Test Operations /Second. All ICs TTL; costs less than $20.00). Circuit is easy to understand and build. Illustrated Plans. $20.00; NORTH - TTL 7491 % OFF ON ORDERS OVER $50.00 ]I 'VP 111rMEMORIES 41 STAR 3617 North Crede Drive, Charleston. 7400 s .14 7493 .60 1 0% OFF ON ORDERS OVER $100.00 ENGINEERING, n1103ot 256 bit RAM MOS S 1.50 7401 16 7494 44 I 5% OFF ON ORDERS OVER $250.00 WV 25302. 2524 bit RAM MOS 1.95 7401 .15 7495 .79 2102 1024 bil slake RAM 5.55 INTEGRATED CIRCUIT TESTER. Easy assembly, under 7401 .16 74% .79 5207 2048 bit UV eras PROM 17.45 7404 .19 74100 1.30 $20.00. Tests Two Input Gates. Inverters in 7400 series. LINEAR CIRCUITS 5260 2024 bit RAM 2.49 7405 .19 74105 .44 300 Pos V 723) TO -5 S .71 Reg (super 5261 1024 bit RAM 2.69 Complete Instructions. Part List. Send $1.00. G.A.L. Elec- 7406 .35 74107 .40 301 Hi pert op amp mDIP .29 5262 2048 bit RAM 5.95 tronics. 32001 Schoenherr. Warren, Mich. 48093. 7407 .35 74121 .42 107 Op AMP (super 741) mDIP .26 7223 64 bit ROM TTL 2.48 7408 .18 74122 .45 708 Micro Pwr Op Amp mDIP .89 8223 Programmable ROM 3.69 MICROPROCESSOR C8080A/8080A Factory Prime. $65.00, 7409 .19 74123 .85 309K lA regulator 10-3 1.35 74200 256 bit RAM tri -stale post paid. Altair 8800 Cassette Interface Kit. $100.00. post 7410 .16 74125 .54 310 V Follower Op Amp mDIP 1.07 Bellflower, 7411 .25 74126 .63 311 Hi pert V Comp mDIP .95 paid. Sargent's Distributing. 10268 Rosecrans. 7413 .55 74141 1.04 319 Hi Speed Dual Comp DIP 1.13 CA 90706. 7416 .35 74145 1.04 320 Neg Reg 5.2, 12, 15 TO -3 1.04 & with 74 .35 74150 .97 324 Quad Amp DIP 1.58 CALCULATOR T.V. GAMES LSI CHIP: Plays 8 exciting games sound 74211 .16 74151 .79 339 Quad Comparator DIP 1.58 CLOCK CHIPS and score. One to four players. Plugs straight into your 7422 .26 74151 .99 340K Pos. V reg. (5V, 6V, 8V, T.V. Full Data included. 7423 Antenna socket. constructional .29 74154 1.25 12V, 15V, 18V, 24V) TO -3 1.69 5001 12 DIG 4 tund lit der 53.45 Postage: 1 to 10 Chips, $40 each; 11 to 50 7425 .27 74155 1.07 340T Pos. V reg. (51/, 6V, BV. 5002 Same as 5001 e.c buy pwr 3.95 Cost, including 7426 .M 74156 1.07 12V, 15V, 18V, 24V) TO -220 1.49 5005 12 DIG 4 fund w /mem 4.95 Chips. $30; 51 plus on application. Orders with Money 7427 .29 74157 .99 370 AGC /Squekh AMPL DIP .71 MM5725 8 DIG 4 fund chain 8 der 1.98 Order or Cash to Television Sports. Ltd., 6 Half Moon 7430 .20 74158 1.79 372 AF -IF Strip detector DIP 2.93 MM5736 18 pin 6 DIG 4 fund 4.45 7432 .23 74160 Street. Mayfair. London. W1Y 7RA. England. 1.39 373 AM /FM /SSO Strip DIP .53 MM5738 8 DIG S land K 8 mem 5.35 7437 .35 74151 1.25 376 Pos. V. Reg ,nDIP 2.42 MM5739 9 DIG 4 fund (blry sue) 5.35 CARBON FILM RESISTORS. Brand new as low as 1.7 7438 .35 74162 1.49 380 2w Audio Amp DIP 1.13 MM5311 28 pin BCD 6 dig mu. 4.45 7440 .17 74163 1.39 cents discounts of 20%. Prompt delivery. FREE 780-8 .6w Audio Amp mDIP 1.52 MM5312 24 pin 1 pps BCD 4 dig mua 3.95 7441 .98 74164 1.59 381 La Noise Dual preamp DIP 1.52 MM5313 28 pin 1 pps BCD 6 dig mu. 4.45 samples/specifications. COMPONENTS CENTER, Box 7442 .77 74165 1.59 550 Prec V Reg DIP .89 MM5314 24 pin 6 dig mutt 4.45 134P, N.Y., N.Y. 10038. 7444 .87 74170 1.30 555 .89 ,64265716 40 pin alarm 4 dig 7444 .87 74170 1.30 556.4 Dual sss Timer DIP 1.49 SONAR VHF FM Business Radio. Pagers, Scanners. 7445 .89 74171 1.49 560 Phase Locked Loop DIP 2.48 Amateur, Marine. L.C. McCann Co., Oley. PA 19547. 7446 .93 74174 1.62 561 Phase Locked Loop DIP 2.48 7447 .89 74175 1.39 565 Phase locked Loop DIP 2.38 LED'S TEKTRONIX and Hewlett- Packard oscilloscopes and test 7448 1.04 74176 .89 566 Function Gen mDIP 2.25 equipment. Free information. American Calibration 7450 .17 74177 .84 567 Tone Decoder mDIP 2.66 MV10B Red TO 18 S .22 Georgia 30601. 7451 .17 74180 .90 709 Operational AMPL DIP .26 MV50 Axial leads .18 Services, Box 8104, Athens, M55020 Jumbo Vk. Red (Red Dome) .22 7453 .17 74181 2.98 710 Hi Speed Voll Comp DIP .35 TV- GAMES. More than a Pong game. 5 game plan 7454 .17 74182 .79 721 V Reg DIP .62 Jumbo Pis. Red (Clear Dome) .22 12 Full description 7460 .17 74184 8.19 739 Dual Hi Pert Op Amp DIP 1.07 M14 Infra red dill. dome .54 set -$5.00. Big game plan set -$12.00. 7464 .35 74185 2.29 741 Comp Op Amp mDIP .32 MANI Red 7 seg..270" 2.19 and specs -$1.00 (refundable). Advanced Electronics. P.O. MAN! Red alpha num .3Y' 4.39 7465 .33 74187 5.95 747 Dual 741 Op Amp DIP .71 Box 1128, Cupertino. Calif. 95014. 7470 .30 74190 1.35 748 Freq Adj 741 mDIP .35 MAN4 Red 7 seq..190" 1.95 MANS Green 7 seg..270" 3.45 7472 .30 74191 1.35 1304 IM Mull'. Stereo Demod DIP . 1.07 CBer's Compander increases talk Power. Superdesigned MANS .6" high slid seq. 4.25 7473 .35 74192 1.25 1307 FM Mulp. Stereo Demod DIP .74 Sweep /Function /FSK generator. More! Minitron. Box 184, 7474 .35 74193 1.19 1458 Dual Comp Op Amp mDIP .62 MAN] Red 7 .q..270" 1.19 7475 .57 74194 1.25 1800 Stereo multiplexer DIP 2.48 MANS Yellow 7 seq..270" 3.45 Anoka, Minn. 55303. .4" high solid seq. 2.95 7476 .39 74195 .89 moo Quad Amplifier DIP .I5 MAN64 OPTICAL SCANNER for bar coder. $15. postpaid. Creed 7483 .79 741% 1.25 8038 V contr. osc DIP 4.95 MAN66 .6" high spaced seq. 3.75 MCT2 61 with 8008 or 8080 (ALTAIR) interface and manuals. 7485 1.10 74197 .89 8864 9 DIG Led Cath Drvr DIP 2.25 L Oplo -iso transistor teletype 7486 .40 74198 1.79 75150 Dual Line Driver DIP 1.95 $150. Wilcox Enterprises. 25W178 39th Street. Naperville. 7489 2.48 74199 1.79 75451 Dual Peripheral Driver mDIP .35 Ill. 60540. 7490 .59 74200 5.90 75452 Dual Peripheral Driver mDIP .35 75453 (3511 Dual Periph. Driver mDIP .15 CMOS 4015A 1.49 4049A .59 MEMORY 21L02A Static Rams $2.75, brand new. Wm. 75491 Quad Seq Driver for LED DIP .71 10168 .56 4050.4 .59 Witherspoon. 3558 Stony Point Road. Grand Island. N.Y. 175492 Hey Digit Driver DIP 80 OOOOA S .M 10178 1.19 4066.4 .89 40014 .25 4020A 1.49 40684 .44 14072. 4002A .25 40214 1.39 40694 .44 FLAT PANEL LOUDSPEAKERS. Super fidelity and also alislation guaranteed.a'mleed eShre"eShipment 1 will be made via first class mail within J da Ys Irom recei l P o 4006A 135 40224 1.10 40714 .26 loudspeakers that can order. Add 5.50 to rover shipping and handling for orders under 525.00. Minimum order 55.00. 40074 .26 40234 .25 40724 .35 revolutionary communications California residents add sales tat. 4008A 1.79 40244 .89 40734 .39 double your receiving range. Lifetime guarantee. Mignon .57 4025A .25 Products, 352 Old Country Road. Fairfield, N.J. 07006. INTERNATIONAL ELECTRONICS UNLIMITED 4010A 4079A .39 20 4028.4 % 0081.4 M CARTRIVISION -Color video tape recorders, TV cameras. P.O. BOX 1708/ MONTEREY, CA. 93940 USA 4201" 40124 .25 40304 .44 4082A .35 face plates, heads, blank tapes, spare electronics. Send PHONE (408) 659 -3171 40134 .45 4035A 1.27 4528A 1.60 ail SSAE for price list. Phoenix Services, Dept. P2, P.O. Box 1014A 1.49 441420 1.47 4585Á 2.10 6509, San Jose, CA 95150.

CIRCLE NO. 17 ON FREE INFORMATIO 108 POPULAR ELECTRONICS

www.americanradiohistory.com Altaj Electronic Bargains PRICES SLASHED! WE WANT YOUR BUSINESS. SATISFACTION GUARANTEED ON EVERY ITEM

LM309K 3 DIGIT LED READOUT ARRAY LITRONIX DL707 TO-3 Case, 1 AMP 5 VDC Voltage Regula- tor. Brand New By National $1.19 Like Litronix DL -33 3 MAN -3 style read- READOUTS outs in one package. Factory new units .30 IN. CHAR. Common Anode. Designed for calculators. Special - $1.39 (3 Digits) SPECIAL - $1.19 CALCULATOR CHIP BONANZA PRICES SLASHED! The newest and easiest to use chips DIGITAL ALARM CLOCK IC FLOURESCENT available today. Made by famous US mfg. The newest and easiest to use alarm chip READOUT TUBES All are 28 pin DIP. Features: direct LED on the market today. Features: 7 Segments. Blue-Green in color. Mfg. by low 6 DIGIT LED READOUTS segment drive, power consumption, 1. Single supply voltage. ISE. #DG8F. The most popular display internal keyboard debounce, internal Brand new arrays by T. I. Common Ithip2. LED Intensity control used in many imported clocks and calcu- cathode, properly multiplexed. Six digits clock oscillator, single supply voltage, 3. Simple time set. lators. Perfect for use with MM5316 clock plus a negative sign. Perfect for calcula- internal keyboard encoding, and floating 4. 4 or 6 Digit LED Display chips. Does not require many tors, mini- clooks, stop watches, etc. decimal point. 5. AM -PM Indication SUPER SPECIAL 69c ea. SUPER SPECIAL $1.29 external components as do older types 6. 24 Hr. Alarm. 12 For $5.95 ea 3 for $3 like CT5001, 5002, 5005, etc. We offer the 7. 10 minute snooze. most U.V. ERASEABLE PROMS sophisticated functions for the 8. Outperforms MM5316 GE TRANSISTOR lowest New Prime units by National price anywhere. ASSORTMENT Chip #1 - 8 Digit, Constnat, Six Func- Order #70250 - $4.99 MM5203 2K $14.95 tion (+,-, x, +, %, ) -$2.49 One of the best mixed transistor lots we MM5204 4K $19.95 MM5314 have seen. TO -98 Plastic cased. Includes TRANSISTOR MOTOROLA MJE 3055 NATIONAL CLOCK CHIP Darlingtons, SCR's, PNP, NPN, etc. Un- BAKER'S DOZEN SALE! Plastic version of 2N3055. NPN Silicon. The most popular clock chip around. We tested sample test shows very high yeild. 2 million pieces for this sale. New 90 Watts 15 Amps. SPECIAL - 69c made a huge special purchase of factory Satisfaction assured. 50 for 99c bought fresh, prime units. Lowest price in USA. SPECIAL: 6 BAGS FOR $5. house numbered units by T.I. All prime 8008 MICROPROCESSOR 24 Pin DIP. 4 or 6 Digits. With Specs. first quality at a give -away price. $3.95 COLOR ORGAN CONTROL NPN 2N3904 -13 For $1 Computer on a chip. 8 Bit Parallel CPU. PNP 2N3906 -13 For $1 Can address 16k x 8 bits of memory. With DOUBLE DIGIT MODULE specs. Factory tested units. Completely self -contained. Has SCR cir- In4004 RECTIFIERS $24.95 JUMBO READOUTS cuitry, AC line cord, etc. From a close 1 400PtV 151$1 New. Litronix 727. Dual. Perfect for giant out by a mfg. of color organs. New AMP SPECIAL 2102-1K RAM's for above - clocks, etc. unused. $4.95 or 8 For $30 $3.95 each (2 DIGITS) $1.49 7805 STYLE REGULATORS TO -220 Plastic Case 5VDC Regulator. TTL SUPER SPECIAL JUMBO LED READOUT MOTOROLA SCR Brand New by National - 99c 74121 - ONE SHOT 4/$1 Twice the size of regular readouts. .65 2N4443 8 Amp 400PN, Plastic Power inches. Like Litronix DL747. Outperforms Case. 69c FACTORY NEW LED'S LINEAR IC SPECIALS and easier to read than SLA -3, only 20 Jumbo Red -Like MV5024 -8/$1 MA 555V -75c 567V -$1.95 723CH -59c per segment. Our best readout for GE POWER DARLINGTON Jumbo Green -Like MV5222 -5/$1 digital 741 CV -25c LM324 by National Quad clocks. NPN, Plastic Power Tab Case. VCEO-30 Jumbo Yellow-5!$1 - $2.95 ea. (6 FOR $15) Common Anode 741C in one DIP - $1.19 HFE- 30,000 TYP. Brand new units, but Mini Red -Like MV50 -10!$1 FILTER CAPS leads are slightly trimmed for P.C.B. 12VDC REED RELAY #D40C1 - SPECIAL 4 For $1 1000 MFD 16VDC upright style. FORD SOLID STATE MODULES Coil is 500 OHM. SPST -No. Mfg. by Contralab for Ford car radios. $1.49 Sub -Mini. 4 FOR $1 RCA PHOTO DETECTOR - Each module contains 2 transistors plus POWER AMP. IC 8038 FUNCTION GENERATOR other components. These modules were PRIME TTL DIP IC'S RCA CA3062 for photoelectric applica- Brand new. Voltage controlled oscillator. used as audio pre amps. We include tions. The IC with a window. Contains Has sine, square wave, and specs. -4 For $1 7400 -16c 7448 -89c 74151 -75c triangular photosensitive section, amplifier, and 7402 -16c 7453 -16c 74153-89c outputs. $4.95 each. high current output pair of transistors. 7404 -16c 7473 -37c 74154-95c Has 100 MA output. Useful for intrusion TTL IC ASSORTMENT 7406 -24c 7474 -37c 74157-99c IN4148 DIODES alarms, counters, position sensors, etc. 7808 -16c 7475-65c 74161 -99c Brand New Units. Same as IN914. Full with complete spec sheets. Reg. $4.84. Various types. Most are marked. Our best 7410 -16c 7476-39c 74163 selling -1.19 Leads. SPECIAL - $1.99 assortment. Untested but in- 7413 -49c 7483 -85c 74164 -1.89 25 For $1 cludes many useable devices. 7420 -16c 7490 -69c 74165 -1.49 LOOK MOS 4 DIGIT COUNTER 200 PCS FOR $3.95 7427 -24c 7492 -75c 74174-1.29 MONSANTO COLORED 7430 -16c 7493 -75c 74175-1.39 An ALTAJ exclusive. These are the latest READOUTS MOS a famous 7437 -39c 7495 -75c 74181 -2.75 state of the art, chips. By FM TRANSFORMERS 7438 -35c 7496 -75c 74192-1.25 .27 IN. Character. Common Anode. US mfg. Contains a complete 4 digit 7440 -16c 74121 -38c 74193-1.25 MANS GREEN $1.29 counter, including 4 decade counters, We bought a load of coils and trans- - - formers 7442 -69c 74123-75c 74195-79c MAN 8 - YELLOW - $1.29 latches, multiplexing circuits, display that were used in Ford AM-FM 7447 -89c 74150-70c 74197-79c decoders, etc. Features: 5VDC operation, car radios. Includes 19KHZ, 38KHZ, PHASE LOCKED LOOP 25 MW power consumption, both 7 seg- OSC. Coils, etc. All New. Perfect for ment experimenters or repairmen. 10 Pc 565A by Signetics. Extemely stable. High and BCD outputs. Perfect for mak- Asst. COMPUTER BOARD BONANZA linearity, wide frequency range. TTL ing DVM's frequency meters, tacho- -99c meters, stopwatches, or any other device We bought over 4 tons of assorted compatible. Perfect for tone decoders, FSK, SCA receivers, frequency multipli- requiring 4 or more digits. Complete with boards. Contains TTL, diodes, transis- specs 28 PIN QTY cation and division 99c DIP, Limited. TANTALUM CAPS tors, etc. 5 board assmt. with 150 to 250 - SPECIAL $12.50 IC's WITH SPECS - VDC. Axial - $3.95. BACK IN STOCK! By Sprague. 4.7 MFD 10 Leads. Perfect for timers. LED DRIVER IC'S 10 For $1 75491 Quad segment dr. - 29c C-MOS 75492 Hex digit dr. - 39c TRANSFORMER SPECIAL #1 Miniature size. Primary 115V RCA FM IC AC Second- CD4000 24 CD4015.1.19 CD4026.1.49 CD4044...59 CA3043 - ary 11V AC No Load. 8V AC with 400 MA CD4001 24 CD4016...59 CD4027...59 C04047 ...59 Used in FM stereos. Contains IF Amp, Load. Perfect for clocks or calculators or CD4002 24 CD4017.1.29 CD4028...99 CD4049...59 Limiter, FM Detector, and an Audio small power supply. 99c CD4006...1.49 CD4018.1.49 CD4029.1.39 CD4050...59 Preamp and Driver all in one 12 lead TO-5 CD4007 24 CD4019...59 CD4030...49 CD4066...99 package. With Spec Sheets. CD4008...1.15 CD4020.1.59 CD4032...24 CD4077...39 A $3.00 Value - 99c CD4009 59 CD4021 .1.49 CD4033.1.49 74CO2....29 Altaj Electronics CD4011 24 004022.1.19 CD4035.1.39 74004 ....29 4 DIGIT ALARM CLOCK KIT P.O. Box 38544 CD4012 24 004023...24 CD4040.1.59 74C107 .1.29 Features the only LED direct drive clock CD4013 59 004024...99 CD4041 ...89 Dallas, Texas 75238 chip on the market. Kit includes all parts CD4014 . . .1.49 CD4025 . . .24 CD4042 . . .79 (except X fmr) for a 4 Digit alarm clock TERMS: Check or money order. No. Uses .25 inch kit. LED readouts. COD. Add 10% Pstg. and Hdlg. Tex Res. SPECIAL: $15.95 PC Board) (with add 5 %.

CIRCLE NO 6 ON FREE INFORMATION CARO

JANUARY 1976 109

www.americanradiohistory.com T 7400N TTL 7 JAMES JANUARY SPECIALS 74LS00 llélY I P7 * 741500 39 741355 .39 74L5151 1.55 *Astrisk Denotes Items On Special For This Month* 741502 .39 741573 65 7415153 1.89 SN740010 .13 S374511 27 SN74151N 1.25 741003 39 741074 65 7415157 1.55 SN7401N .16 SN7453N .27 SN74153N 1.35 741504 45 741575 .79 7415162 2.25 SN7402N 21 SN7451N 41 1,25 5174154N0 741505 45 741576 AS 7415163 2.25 .16 5174594 .25 1.21 ,1551111 SN7403N SN71155N *Special Requested Items* 741508 .39 741563 2.19 7115164 2.25 SN7404NA .16 517460N .22 SN741563 1.30 741510 .39 7/1586 .65 7415181 3.69 SN7405N .24 SN7470N 45 5374157N 1.30 8C4194 Dual Track V rep E 5 95 N8T97 $ 3.00 M1E5007510.95 MC4044 4.50 741513 79 741590 1.25 7415190 2.85 SN74063 45 SN74723 39 S3741605 1.75 4024P 2.25 8263 5.95 LM3909 2.25 804195 150 Track Rep 3.25 741514 2 19 741592 1.25 7415191 2.85 1.15 MM5320 19.% SN74073 45 53747330. 37 SN74161N 79368 Decoder 3.95 2513 11.00 8287 2.75 741520 .39 741593 125 7415192 2.85 74279 SN7408N .25 SN747430 12 S37116330 135 L0110n11 DVM Chip Set 28.00 2518 7.00 8288 1.15 90 741526 49 741595 2.19 7415193 2.85 40724E 45 SN7409N .25 53747510 .59 S1711643 1.65 CA3130 Super CMOS Op Amp 1.19 2524 3.50 8826 3.00 741527 .45 741596 1.09 7410194 2 25 45114E 2.50 SN7410110 .16 SN717610 32 S1741653 1.65 MC1408L7 AID 9.95 2525 6.00 8800 115 741528 49 7415107 .65 7415195 2.25 4136 2.50 5174111 .30 SN7480N .50 SH74166N 1.70 73341 FIFO 8.95 2527 5.00 7197 5.00 741530 39 7415112 .65 7415257 1.89 SN7412N 42 SN7482N 1.75 53741673 5.50 741532 .45 7415132 1.55 7415260 55

1 TO ON YOUR SPECIAL PARTS 5374133 85 537483N 15 5171170N 3.00 WE'LL BE HAPPY QUOTE - 741540 49 7415136 65 7415279 79 70 SN7411N SN74853 1.12 SN74172N 18 00 741551 .39 7115138 1.89 7410870 5.95 S374161 43 5147486N 45 SN71173N 1.70 R - RED 537417N 43 SN748433 3.50 SN71174N I.% XCITON OPTO ELECTRONICS DPST They are rated as 115 Vac 49 SA 5374183 25 5374893 100 5374175N 115 G - GREEN They are excellent in applications 21 5374203 53749310 .19 53741795 .90 LITRONIX C & K ROCKER SWITCH such as Microcomputer 5174213 39 SN74911 1.20 S374177N BO DISCRETE LEDS Y - YELLOW Dim: 1 "x 1 "x Vaa" Panel Switches SN7423N 37 SN7492N .82 53711895 1,05 MONSANTO $0.69 O 5374253 43 SN749330 17 5374181N 3.55 - ORANGE 5374269 31 53719/N 11 51171182N .95 OPOT 1929 MINATURE SN7427N 37 537495N .91 5371184N 2 30 111

SN742984 .42 4111- OFF 1 TS 537496N .91 53741853 2.20 246 TOGGLE SN74303 .28 SN7410090 1.00 5374187N 680 .125" dia. .18511 dia. .190" dia. 537432N 31 SN74107N .49 SN741994 1.50 NOW 2722 2.64 1M SN74373 .47 S974121N0 45 SN74191N 1.50 XC209R 541 XC526R 531 8011IR 5/01 40 S374381 SN74122N .49 S37419210 1.19 5C2096 431 XC526G 431 XC111G 4/51 OFF 1 5574395 25 53741239 0 70 26 I 96 42 5174193N0 19 XC203Y 431 XC526Y 131 XC111Y 4/$I 21 SN74403 SN741253 .60 5374194N 1A5 XC2090 4/51 024260 4/51 001110 441 OH ON 206 1.66 110 537441N 1 10 53711265 .81 SN74195N 1.00 rot 123 SN7442N 1.08 53741323 3.00 55741%N 125 SN7443N 1.05 SN741413 1.15 511741979 1.00 917444N 1.10 9474142N0 4.00 S971198N 2.25 Model I IIM SN7445N 1.10 5374143N0 4.50 SN7/1993 2.25 ..*-"6.^-^' 01.089 den Sumter b9 1P29 30.98 SN7446N 1.15 S1741443e 4.50 557420014 7 00 ua dia. .200" dia. .085' dia. $235 S67447N0 39 1.15 .200" e.P&123 S1.95 5147 31.30 5174145N SN74251N 2.50 MA....N4.an-p.a- S117448N .99 94741183 2.50 SN712843 600 XC22R 531 XC556R 5/$1 MV50 . PB-126 52.35 51.95 51 47 51.30 SN74503 .26 5N741508 1.10 53742853 6.00 8022G 431 005566 431 .085" dia Micro XC22Y 431 X05560 4/$1 red led MANY OTHERS AVAILABLE ON REQUEST X(220 431 8C5560 431 641 20' Dianom Inr 100 Combined 7400'5 DISPLAY LEDS THUMBWHEEL SWITCHES 7401051 65 Dv47 C04000 25 S CM O 74C20N 65 CD4001 25 «' 74C30N 004002 25 CD4030 65 65 070 DL7O7 MAN2 ® MA813 Single Pole 7404284 215 C24006 2.50 CD1035 1.35 RGEZI epo,ecoo 71C73N 1.50 ®IMAN7 004007 .25 C04040 2.45 Q ó DL33B C04009 19 C04042 1.% 74071 1 15 74CBON 3.00 104010 .59 004044 150 TYPE POLA8517 TYPE POLARITY NT HT U111.11111APANIY.Phow. MT re 104011 .25 CD4046 2.51 74C95N 2 00 MAN 1 COMMON ANODE .270 S1 95 MAN 74 COMMON CATHODE 303 51 50 .25 2 7401073 1.25 CD4012 244047 75 MAN 2 5 e 7 DOT MATRIX .300 3.95 07707 COMMON A ODE 300 51 50 47 74C151 2.% CD4013 004049 79 MAN 3 COMMON CATHODE 125 39 01747 COMMON ANODE* 600 1 95 740154 3 00 004016 .56 104050 79 MAN 1 COMMON CATHODE 187 1.95 01750 COMMON C THODE 600 2 49 C04017 1.35 2.% 74C157 2.15 004051 MAN 7 COMMON ANODE 300 1 50 0133e COMMON C THOOF 110 1.% .55 740160 3.25 CD4019 CD4053 2.98 MAN 7G COMMON ANODE -GREEN 100 2.50 FND70 COMMON C THODE 250 50 1.49 740161 3.25 ACL SSORIp44aPruea ACCESSORIES 004020 104060 3.25 MAN 7V COMMON ANODE- YELLOW .300 2.50 FN0503 COMMON CATHODE 500 I 75 74C163 3.00 AIelPanll4a Pd PAR P0 0046 CD4022 1.25 C01066 1 75 FN0507 COMMON ANODE 500 175 MAN 72 COMMON ANODE .300 150 v EVA S 50 SR FP E.dP0480 l ílá 74C164 3.25 104023 25 CD4069 45 Dp Divider Pam seans 45 SR DP o ".a1 Pine rearm 40 CD4024 1.50 004071 45 740173 250 5R RB Blank Soyy leach) 40 HB Han 9401 40 CD4025 25 C04081 45 74C193 275 SR Rosy IC SOLDERTAIL LOW PROFILE (TIN) SOCKETS 004027 .69 740003 39 740195 2.75 - PDT SWn6II 80097 1.50 054028 115 740028 55 HIGH QUALM/ P C. TYPE 69 ea. CD4029 290 740048 75 1.24 25 -49 50 -100 124 25 -49 5001n0 I :- PUSH BOTTOM SWITCHES A pie 117 16 15 24 pin 138 37 36 FOR INSTRUMENT APPLICATIONS 14 pm 20 19 1B 28 pin 45 44 43 /4 e la e 3, 69c each 1441004 15.00 LINEAR LM1310N 215 16 pin 22 21 20 36 pin 60 59 50 LM1064 250 LM1351N 1.65 18 pin 29 28 27 40 pin 63 62 51 ZENERS- DIODES-RECTIFIERS L1A171H 3.75 22 pm 36 35 LM3731 3 25 18414148 1 75 37 SOLDERTAIL STANDARD (TIN) 1M212H 7.00 LM377N 4.00 LM1458C .65 TOPE VOLTS W RICE TYPE VOLTS W PRICE LM300H BO LM380N 119 .% LM1496N 28 99 90 et 14 5.27 25 .24 pin 0 N146 33 400m 1 00 N4003 ZOO PIC I AMP 10 7M301H0 3/100 LM380CN 1,05 1611556V 1.05 pin r 25 36 pin 1.39 1.26 115 16 pin .30 27 YV- ~ NISIA S I 40004 I nn 54004 400 PIN I AMP 10 LM301CN0 3/1 00 11438111 1 79 LM21119 1.95 40 pin 159 145 1 30 18 pin 35 32 30 - -- N/57 51. 400. I OC N36110 50 6 I DO LM302H 75 LM382N I.79 LM2901N 215 700. 49 42 24 pin 45 5753 6 7 400m 1 Inn' 15 I DO LM304H 1.00 NE501K 800 LM3065N .69 00 54148 15 40061 LM305H 95 NE5104 6.00 0139008 .55 SOLDERTAIL STANDARD (GOLD) N154 G8 00 54154 35 10m 17100 LM307CN 35 NE53IH 3.00 LM3905N .60 59558 15 40D0. 100 64734 5 fi w 28 LM308H 1.00 NE5367 6.00 1.85 55137 513 500. 20 614135 62 Iw 78 LM5556N 8 pin 5.30 27 24 , ,. á` 24 pin S. 70 83 .57 LM308CN I.00 NE540L 6.00 MC5558V 1.00 1 10 1.00 90 55234 6 2 500. 28 54736 5 8 4w 78 14 pin 35 .32 29 5 28 pin LM309H 1 1 8 110 NE550N 79 1M7525N .90 16 pin 18 .35 32 ' 36 pm 75 40 1.28 55735 6 8 60001 28 64/3F 7 1* 28 LM309K 1.25 NE553 2.50 LM7528N 2.20 10 pin 1.75 1.59 1 45 55736 1S 500m 70 64147 12 I+a 78 1.15 LM31001 NE555V0 45 LM7534N 2.20 WIRE WRAP SOCKETS (GOLD) LEVEL #3 N456 25 4063 6 1 GO N4/44 IS Inv 24 183114 .% NE565H0 .99 L1475351 125 6458 150 1m 6 I 00 51183 50 PG/ 35 AMP Ion LM311N % 1,25 NE56530 803880 4.95 N485A 180 IDm 5100 51184 Inn PIV 15 AMP I /0 10 pin 5.45 11 .37 24 pin 51.05 .95 85 LM318CN 1.50 1.85 1875450 49 °e..._ NE566C0 54751 50 PA/ I AMP 09 N1185 700 PIV 1S AMP 180 M 39 .38 37 *-,--4,,r., 20 pin 140 1.25 1.10 LM319N 1.30 NE567H 39 pin 75451CN I 125 AMP IO N 1 106 100 PIV 15 AMP 1DO 16 pin 43 42 41 - - 36 pm 1.59 1.45 1.30 N4D07100P1V LM3190 9.00 NE567V0 1.50 7545203 .39 18 pin 75 .68 62 40 pin 775 1.55 1.40 LM320K-5 1.35 LM703CN .45 7545301 .39 TRANSISTORS P54249 4 00 1.832065.2 1.35 MPS 405 01 00 SI LM70911 29 75454CN 39 PN0567 3 00 PAPS A06 51 00 II P54250 4 SI CO LM320K-12 1.35 L147093 29 75491CN 79 4 2622198 51.00 P70568 51 00 2.4400 4 51 00 LM320K-15 1.35 LM710N TO P73569 4 SI 00 7549201 89 50 PCS. RESISTOR ASSORTMENTS $1.75 PER ASST. 211221 51,00 294401 d 51 CO LM3206-5 10.50 5 SI 00 LM711N .39 75494CN .89 252222A 51 CO 261704 294402 4 $100 10 OHM 12 OHM 15 OHM 18 OHM 22 OHM 5 S1 00 LM3246 1.80 LM723N .55 RCA LINEAR 2112369 SI 00 00705 L 2N4405 4 SI 00 5 51 00 1 70 1 47 OHM 56 OHM 1/4 WATT 5% = 50 PCS. 273706 284409 5 51 00 LM339N LM723H .55 CA3013 1 70 ASST. 5 ea. 27 OHM 33 OHM 39 OHM 252369A SI 00 273701 5 51 50 00 161340K-5 1.95 LM733N 1.00 CA3023 2.15 FN2415 SI CO 255086 SI 68 OHM 82 OHM 100 OHM 120 OHM 150 OHM 5 301454 S1 00 285111 SI 00 295087 4 61.00 LM3406-12 1 95 LM739N 129 083035 2.25 WATT = 50 PCS. S 65 ASST. 2 5 ea. 180 OHM 220 OHM 270 OHM 330 OHM 390 OHM 1/4 5% 7529064 S1 00 255724 I 295086 4 51 CO LM3404-15 1.95 LM741CHe 3/1.00 CA3039 1.35 2529074 51 00 210725 SI 00 255089 4 SI 00 LM340K-24 1.95 1.15 470 OHM 560 OHM 680 OHM 820 OHM 1K LM741C30 3/1.00 0A3046 292925 01 3p 2N3903 5 SI 00 265129 5 S1 00 LM3407-5 1 75 1/4 WATT 5% = 50 PCS. LM741 141 .39 CA3059 2.46 ASST. 3 5 ea. 1.2K 1.56 11K 22K 2.76 752053 SI 00 263904 4 S1 00 265158 5 SI 00 LM340T-6 1.75 LM747H .79 2_80 250905 4 51 00 5 00 CA3060 3.3K 3.96 4.7K 5.64 6.86 .53055 S 89 255139 $1 4 1M340T-12 175 1117473 .79 CA3080 85 511E3055 5 89 253906 71 00 255209 5 51 00 ASST. 4 5 00. 112K 106 12K 15K 186 1/4 WATT 5% = 50 PCS. 1643107-15 1.75 1874811 .39 043083 1.60 1N339I 5 SI 00 294013 I SI 00 265951 5 SI W 2N4014 3 SI 00 L106615L21 2 LM340T-24 1.75 1M7488 .39 CA3086 .59 226 27K 33K 39K 176 71.1171 5 SI 00 5' M' LM350N 1.00 1813038 .90 3.25 5% 50 PCS. CA3089 ASST. 5 5 .a. 565 68K 826 100K 1206 1/4 WATT = LM351CN .65 L1413013 1.19 CA3091 825 1506 1606 22055 2706 330K LM3703 1.15 1813051 1.40 CA3123 I 85 = 50 PCS. CAPACITOR CORNER 10 LM37011 1.15 LM1307N .05 175 ASST. 5 5 a. 39015 4706 5604 6905 8206 1/4 WATT 5% CA3600 AO VOLT CERAMIC DISC CAPACITORS' 1M 1.2M 1.5M 18M 2.2M I'I 1049 SO 100 9 : Sn MO 4.7M 16M 1/4 WATT 5% = 50PCS. ASST. 7 Yea. 2.7M 3.3M 3.9M 55 111 01 VIII 115 01 075 05 04 03 0114 I 05 111 1135 ALL OTHER RESISTORS FROM 2.2 OHMS 5.6M AVAILABLE IN MULTIPLES OF 5 e

01 05 04 01 n 05 04 895 100 -495 PCS: .03 ea. 500 -995'. .027 ea KITS EXAR Ics 5.25 PCS: .05 ea. 30 -95 PCS: 04 ea. 1011111 55 04 01 III? 06 05 04 120 01 05 04 01 Dal Ill. n'. 00 14 PCS. POTENTIOMETER ASSORTMENTS KR 2206KA i I 1 / 0 1 0 / 7 SPECIAL S17.95 / 0 0 1 OS 04 035

IoLlnlle5 ,1 ASST A Zea 10 OHM 20 OHM 50 OHM 100 OHM 200 OHM 250 OHM 500 OHM LH01LI.001e1e.dtn.IC PChnn.n..:,i1d512n1n6 100 VOLT MIL AR FILM CAPACITORS 11S11041n1.. .11.11 011 ASST 8 Zea 16.2K. 25K 10K. 208. 256. 50K 001891 11 10 07 022891 13 II 08 Per Asst. 0022 11 10 01 041311 21 17 13 KR 2206K8 SPECIAL ASST C Sea SOK 1006, 2008, 250E, 500K IM_ 2M $9.95 $27.95 0047891 Il IO 01 1141 21 23 17 SOnle 4, XR 721111K also ve 4111I r.1c1011e5 Pe1e111a1 clmp00e'1I 17 10 07 22.1 33 21 25 Ea assor meal contains 14 pes 0110 turn poll All pals we available .4 single um! guanIn.es. 5.99 es. Olmt lui PC 1111.011 2M. CUPPED TANTALUMS ISOL 101 CAPACITORS 156 /F 73 I5 156 10 71. /I 00 1401 1402 7407 7404 Asst 55. 17I S595 4S7T IS 150 78 23 I 17 756 31 71 11 PRIME 947410 7430 743e 4 7 TIMERS WAVEFORM GENERATORS 77. 'SV 74 21 I 1 3 75V II 71 77 7490 7497 00 4191 INTEGRATED 41019 70. Ast to 79754557 13 ISV 78 21 I 4 1 755 II 1F 7; XR-555CP S .69 OR 53.20 51274145 4175 14140 74191 74193 II 156 78 71 I I.1 255 11. 31 75 XR320P 1.55 OP. 3.20 CIRCUIT 2206CP 4002 san 4011 I., 15V 78 73 1 10 050 10 35 79 lea C04001 LAOS X R 556CP 1.85 XR 2207CP 3.20 ASSORTMENTS C04016 400 4019 4011 4010 I0 155 78 7T IS 25V 63 50 40 1411019 30112 3077 4071 lasa XR 2556CP 3.20 11 733 7112144 54995 ASST MINIATUR ALUMINUM ELECTROLYTIC CAPACITORS STEREO DECODERS °511 IÁ7111 5657 5617 140 14.5 A. I Lead Rad01 Lao OR 2240CP 3.25 XR 1310P 840 41 sn S II 0 41 75 5 1 12 4 OR 1310EP 4.49 la I 6 PHASE LOCKED LOOPS Min. Order. U.S. Funds. 50 L 50 Guaranteed. IT 5 1 OR 1800P 385 Satisfaction $5.00 11 50 5 Il 0 XR210 5.20 I 15 . 4 California Residents - Add 6% Sales Tax 4 75 1. 14 7 XR 215 6.60 MISCELLANEOUS Sheets .25E each In 25 5 II 0 50 6 1 for FREE 1976 Catalog Data / IT 5 I Write - In s0 . II 2 XRS67CP 1.95 XR 6.70 2211CP 5 I ñ 77 75 1 15 7 I 75 XR 2567CP 2.99 OR 3 79 2261 72 50 4 70 F I Sn I. 1 134 11 7!. 9 II a I II, 4 0 I 5 11 50 S 01 'I 75 d 17 100 75 4 711 8 I 50 I.

DATA HANDBOOKS 4 1 1'1 100 SO 15 10 1 770 75 37 78 5 In U. 9 S 7400 P.m pul A Description of 5400/74001 C5 52.95 7/t E o 770 SO 15 4I 8 In 75 4 0 ICS P.O. BOX 822, BELMONT, CA. 94002 0 CMOS Pm out 8 Oeecnptlon of 4000 Series 52.95 alo 75 13 71 l In SO l5 HUM IB S5 5 11 It. 71 LINEAR Pin olle A Functional 0 nu, 511511 52.95 50 n .P PHONE ORDERS (415) 592 -8097 nnn IT In la , 1II ., ALL THREE HANDBOOKS 58.95 - J 110 POPULAR ELECTRONICS

www.americanradiohistory.com CONTINENTAL $15.95 MICROPROCESSOR COMPONENTS JE SERIES KITS SPECIALTIES JAMES ELECTRONICS IS PROUD TO ANNOUCE, FOR THE FIRST TIME EVER, TO THE ELEC- TRONIC HOBBIEST .. FROM AMERICAN MICRO DEVICES. JE801 oven The 3E801 is and one half digit. auto PROTO BOARD 6 athree polarity The PB -6 lets the user test and build digital voltmeter, In a kit form It features several circuits without soldering or patch options not available in any commercial digital vol- cords: all inlerconnecions between tmeter. Its low cost is perhaps the most important components are made wilt com- Mature. which is achieved by offering It Ina kit form. mon #22 AWG hook -up wire. This A St allows the uno to be used by small OEM's quality breadboarding tut inludes 80ß0A $39.95 where costehechveness S an important factor, and 630 component tie points al ass 8080 AND 8008 SUPPORT COMPONENTS by the hobbyist who has to be concerned with Cost. Inan 2.5c each. It measures 6" long The unit also features on card regulators. allowing it 8224 CLOCK GENERATOR USED TO GENERATE TWO PHASE 74LS138 DECODER PERFECT FOR DECODING THE THREE by 4" wide. Designed specially to to he operated o8 a single plus and minus fifteen CLOCK NEEDED BY THE 8080 512.95 BOOB STATE LINES INTO 8 USEABLE LINES FOR ADDRESS Breadboard Microprocessor Cir- volt, unregulated power supply_ The unit has a LATCHING 53.58 Qman sue Cl three inches widhh. Anse and three cuits. 515.95 8228 SYSTEM CONTROLLER GENERATES A SYSTEM DATA 8212 B BIT INPUT OUTPUT PORT DIRECTLY INTERFACES uarters of an inch length. and one and a quarter BLS AND CONTROL SIGNALS FOR MEMORY $21.25 THE TO PROVIDE PROTO BOARD 100 WITH BOBO I/O INTERFACE $5.75 inch height. A low cost, big 10 IC capacity breadboard lot with all the quality of CPU'S RAMS $39.95 Per Kit printed board OT sockets and the best of the Proto 8008 8 BIT CPU 519.95 1101 25601 STATIC 52.25 circuit Board serets oonglete down to 8080 SUPER 8008 39.95 1103 102451 DYNAMIC 6 95 the last nut. bah and screw. In- 4040 4 BIT 8080 39.95 2101 25661 STATIC 6.95 SR'S 2102 1024x1 STATIC 2 95 cludes 2 OT -35S Sockets: I OT -358 PROBE Bus Strip, 2 5 -way binding posts, 4 2504 1024 DYNAMIC 59.00 2107 409601 DYNAMIC 19 95 JE803 rubber feet, screws, nuts, bons and 2518 HEX 32 BIT 7 00 2111 25604 STATIC 7 95 easy assembly instructions. 2519 HEX 40 BIT 4.00 7010 1024X1 MNOS 29 95 219.95 2524 512 DYNAMIC 3.50 7489 16X4 STATIC 2 49 2525 1024 DYNAMIC 6. DO 8101 25654 STATIC 7 95 2527 DUAL 256 BIT 3.95 8111 256X4 STATIC 795 Bring IC leads from pc board for fast srgnal tracing Iary 2529 DUAL 512 BIT 4.00 8599 1604 STATIC 3 49 and troubleshooting. Inject signals. Wire unused Ñwiw4 2532 QUAD 80 BIT 3 95 91L02 102491 STATIC 295 circuits into boards. Scope probes and test leads lsew msefY1a 2533 1024 STATIC 7 95 74200 IIn N 1024X1 STATIC 6 95 Per lock onto Dynagnp inset Nee circle) for hands -oh 3311 FIFO 6.95 93410 25601 STATIC $9.95 Kit 1 75 testing. Pleste construction eliminates springs, T4LS670 160 REG 3 95 5262 204801 DYNAMIC 2.95 pivots. Non -corrosive nickel /silver contacts for SARIS PROMS printed circuit board connections. simultaneous low resistance AV -5 -1013 20K 5000 56 95 1702A 2048 FAMOS 15 95 PC-14. 14-pit Prato Clip, $4,50 ea. ROMS 5203 2048 FAMOS 14.95 PC-15. 16-son Prolo Clip, At 75 ea. CHAR. 11 2513 GEN 00 8223 3208 BIPOLAR 3 00 PC -24, 24-prn Proto Clips $8.50 ea 7468 RANDOM BITS 3 50 745287 1024 STATIC 7.95 JE804, JE805 SUPPLIES CALCULATOR CHIPS AND DRIVERS THE JE804 AND JE805 ARE POWER MM5725 B DIGIT 4 FUNCTION 51 98 JOLT 159.95 SUPPLIES MOUNTED ON A 11/u x 3' PC DM75491 SEGMENT DRIVER 79 ACCESSORIES BOARD. THEY ARE AVAILABLE IN MM5736 8 DIGIT 4 FUNCTION 86 _5@ tS I DM75492 DRIVER FOR 5736 89 300 mA, -6 @ 250 mA, e12 @ 100 mA SPECIFY VOLTAGE WHEN ORDER- MM5738 8 DIGIT 5 FUNCTION 2 95 CPU ING DM8864 DRIVER TYPE 1 2 00 159.95 DM8065 DRIVER TYPE 2 1 D KIT CLOCK CHIPS JEB04 15 A POSITIVE SUPPLY JEB05 IS A NEGATIVE SUPPLY $9.95 per kit MM5311 6 DIGIT W/BCD S4.95 MM5312 4 DIGIT W /BCD 4 95 MM5313 6 DIGIT W/BCD 4.95 The JE700 is a low MM5314 6 DIGIT CLOCK 3.95 cost digital clock. but CLOCK is a 4 JE700 very high quality unit. The ungfea- MM5316 ALARM CLOCK 95 CT7Oot CAL CLOCK CHIP 5 95 tures a simulated walnut case with dimensions of 6" o Ova" a I" It utilizes a RAM MANTO high brightness readout, and the DIGITAL WATCH READOUT 199.95 MM5314 clock chip. 519.55 FOR WATCHES. USE WITH Io a:o e1 KIT 12 orN Hour OHMS, COUNTERS, ETC 95 115 VAC - HP-5082-7300 ,1001 INCLUDES SOFTWARE. HARDWARE ANO A5SEM' ELY MANUALS. AVAILABLE FOR IMMEDIATE SHIPMENT $19.95 per kit. HP 5082.7300 $159.95in All form $249 assembled Metro numeric readouts a complete with 3" Ont type The JOLT system consists of a set of modular mit' alone constitutes viable computer system wtlh decoderrdriver/Iatch built on the rocomputer boards which can be used smgy or tied to- centrai processor. I/0, Interrupts, timer, read -write men, WALL OR TV DIGITAL CLOCK chip. Only 8 bins (BCD in. DP Latch a complete soltmare debug monitor in read -only- gether to any desired microcomputer syster con - ory, and produce 12 or 24 Hour 115 Vac 55v. figuration. The minimum system is one CPU board, which memory 5082 7300 $5.95 25' VIEWING DISTANCE JOLT SYSTEM DESCRIPTION JOLT I/O Card(PedpMMl IMedeee Adapter) -2 PIA USI HP 5082 7304 chips, 32 l'O lines, tour !Menton lines, on -board decoding JOLT RAM Card Fuly sate 4,096 bytes of RAM wdh 1 1 - r version al 7300 4.95 Manuals in- mtcrosecOnd acoess time and on -board decoding. Hard- and standard TTL drive Filly programmable. IMMEDIATE SHIPMENT. 395.50 ware and assembly mamas included. AVAILABLE FOR cluded AVAILABLE FOR 6 Digit P.C. Mount kit 5140 assembled. 1 %' xlW' XFMERS IMMEDIATE SHIPMENT $199 95 út . 5285 assem- LED DISPLAY bled x 7 same form JOLT Minimal Card - Same size NW' 'I. lai D1747 121 IMAN / That were designed for dock type up- to JOLT Power Supply Operates at 115, +12 and -10 actor as other JOLT cams. Complexly blank. drilled plicaflons. 110 Vac pnmary @ 80 Ho - for coltages. Supports JOLT CPU. 4k butts of RAM and JOLT accept 14, 16. 24 or 40 pin sockets Used additional Secondaries 610 Vac @ or I/O control TV interfaces. I/O card - or. CPU and 8 1/0 cards ManuaN included. user memory panels. 300 mA -200 mA other interface logic. AVAILABLE FOR AVAILABLE FOR IMMEDIATE SHIPMENT. $99.95 kN. 5145 keyboards. LEDs, or 50 Vac @ 30 mA -50 mA IMMEDIATE SHIPMENT $24.95 assembled WALNUT CASE - KIT -All Comp. 8 Case $34.95 Excellent for miniature power supplies JOLT *69 Booster Option File onto JOLT Power Supply 8 gas discharge displays JOLTAccessory Bag - Conains enoughhardware to con - - Wired 8 Assembled $39.95 Bk nect one JOLT card to another Such necessary nemsas Ilal card. Supports CPU. 16k bytes al RAM -or, CPU and SPECIAL $.99 cable mnnedors, cord spaces, hardware, etc AVAILABLE bytes RAM and 8 I/O cards - or, CPU and 4k bytes RAM AVAILABLE FOR IM. FOR IMMEDIATE SHIPMENT 53995 and 161/0 cards. Manuals include. MEDIATE SHIPMENT 524 95 JE010 CALC. VECTOR BOARD 1/16 MULTIPURPOSE KEYBOARDS 5aumpons 1" Hole P- Pattern Spacing Price -busmen reoa Part No Length Wideth 1 -19 2043 MULTIPURPOSE IMMOMMIS Floating dapimal or fixed two -plan add made output Iwleoudel PHENOLIC 64P44 062XXXP 4.50 650 1.72 1.54 Aut markup/Mounttipo uralanon ZO Mo. Touch Toot 169P44 02XXXP 4.50 1700 3.69 132 A41.1011110C constant ....OM EPDXY 64P44 062 4.50 6.50 2.07 1.66 Gam n am $12.95 GLASS 64P44 062 450 8.50 2.56 2.31 at e.aram.+a°,:a.ea a;n órn Glum calculations OPTION6. 169044 062 450 17.00 5.04 4.53 5249 Pawn operations 1 6VAC T 2495 nari 169P84 062 8.50 17.00 9.23 816 T t balance 6 N Alkaline Samos S2.50 lot EPDXY GLASS 169P44 062C1 4 50 17 90 680 6.12 WIRE WRAP WIRE Addressable emory COPPER CLAO AWG COLOR 25 FT. MIN. 50 FT. 100 FT. 1000 FT. 30 AWG WHITE $2 10 $2 75 33 50 524 00 VECTOR WRITING PENCIL 30 AWG YELLOW 2 10 2 75 3.50 24 00 30 AWG RED 2.10 2.75 3.50 24 00 ELECTRONIC ROULETTE 30 AWG GREEN 2 10 275 3.50 24.00 30 AWG BLUE 2 10 2 15 3.50 24 00 Complete kit 30 AWG BLACK 2 10 2 75 3.50 24.00 with all STANDARD WIRE components

AWO COLOR 25 FT MIN 50 FT AWO COLOR 25 FT MIN 50 FT case and RED Vector Wiring Pencil P173 Consists of a hand held featherweight (under one 16 5360 $5.05 24 RED $1 55 52.05 transformer. rice) tool which is used to guide and wrap insulated were led on a 18 GREEN 6125 $410 26 GREEN 51 45 31.90 ll- contained replaceable bobbin. onto component leads Or terminals instal- 20 WHITE $7.55 $14 0 28 WHITE 51.25 51.65 led on pre-punched ''P" Pattern Vectomor04. Connections helween the 22 BLACK $1.90 $2.55 30 BLACK 31 25 E1.65 wrapped wire end component leads, pads or terminals are made by soldering TO ORDER SPECIFY PAGE COLOR AND FOOTAGE 125 FOOT MINIMUM) BOallll Complete with 250 FT of red were. ; $9.50 ea. 6' 2 CONDUCTOR POWER 115 VAC REPLACEMENT WIRE - BOBBINS FOR WIRING PENCIL CORDS 125V @ 5A 3/1$ W36- 3- APkg. 3 (Green) $2.40 x 1'. W36 -3 -B -Pkg. 3 THREE CONDUCTOR POWER SUPPLY COROS (Red) $2.40 sissolasr- A 56 page book on the facts W36- 3-C.Pkg. 3 (Clear) $2.40 NUMBER LENGTH AWG O.O. RATING COLOM PRICE W36 -3 -D -Pkg. 3 (Blue) $2.40 17236 6 18(410341 265 1250W BLACK Special 99 ea of Roulette included. $29.95 Per Kit 10A -125V

17237 6 1/3/414351 253 1250W GREY 1 25 9V BATTERY CLIP 10A.125V ELECTRONIC STANDARD CLIP 17236 B 181410341 265 1250W BLACK Spenal 99 ea CRAPS FOR USE WITH 9V 10A -125V TRANSISTOR BATTERIES 17239 101410341 253 1250W GREY 130 Complete kit 10A -125V WITH 4 LEADS 9/95 ea. with all 17000 4 10141X341 253 1250W BLACK 59 10A 125v components TERMINAL STRIPS case and Satisfaction Guaranteed. Min. Order. U.S- Funds. THREE TERMINAL I1 $5.00 transformer. STRIPS, WITH CENTER o California Residents - Add 6% Sales Tax TERMINAL USED FOR MOUNTING 15 /$1.00 Write for FREE 1976 Catalog - Data Sheets .25e each [Rives

115 VAC AMP TERMINAL PINS TERMINAL PINS FOR MOUNTING COMPONENTS ALSO PERFECT FOR USE P.O. BOX WITH BOARD CONNECTORS 822, BELMONT, CA. 94002 A 56 page book on the facts included. AND SUBASSEMBLIES $1.00/100 PCS. PHONE ORDERS - (415) 592 -8097 of Craps $19.95 Per Kit CIRCLE NO. 28 ON FREE 'RFD-NATION CARD JANUARY 1976 111

www.americanradiohistory.com QUALITY ELECTRONIC COMPONENTS - SAME DAY SERVICE - M 6800 $85

1 u NEW DISCOUNT SCHEDULE 0 KIT -6800, 2 -6810, 2 -6820, and L' SAVES YOU EVEN MORE) J 6830, 6850, APPLICATIONS S 8080A $69.50 2102 $3.50 & PROGRAM MANUALS -$175 Elecsssór ésmbt^andt M ICROPR OS SOR 1024 6e Random Access Memory iAc 0-70°C 480 ns Clock Period 500 ns Typical, 1000 ns Moo R -K ASSOCIATES Box 440 Personal ALARMS Access Time Standard Heavy Duty Professional 11900 CARLTON R. CLE., OH. 44106 INTEGRATED CIRCUITS - TTL, CMOS, LINEAR 8 MOS

7400 249 7451 224 74155. . 71c 4018 . 5144 4518 . 51.28 7401 24c 7453 724 74156 ...771 4019 584 4520 S1.28 INTEL users. Get to 7402 241 7454 225 74157. ...68c 4020 .... 51.56 4527 . 52.00 8080 pocket reference card similar

7403 . . 245 7460 22c 74160 51.19 4021 .. . SI 42 4528 905 IBM S /370 yellow card. $1.25 or 5 for $5.00. 8080 CARD, 29 7404 ..,.. 244 7470 344 74161 ... 51.11 4022 .... 51.18 9E5365 .. 53.25 7405 244 7472 344 74162 .. 51.19 4023 244 9E5404 5204 Hoyt St., Stamford, CT. 06905. 7406 24c 7473 314 74163 .. 51.19 4024 969 665531 .. 51.87 143'.3911 Rq3 Extra 7407 24c 7474 ..,..311 74164 . .. 5128 4025 244 8E5540 .. 5187 COMPUTER, 8 bit serial, complete. $225. Scope display Belt Or Shoulder Loud 7408 .... 241 7475 517 74174 . .. 51.09 4026 .... 5I67 Nf555V....485 generator. 128 characters. parallel input. $85. Brochure 10 Attachment Loud Screaming Trumpet 7409 . . . 4027 . . 244 7476 .349 74175 51.02 64c NE556A. Siren Speaker 7410 24c 7480 68c 74180 774 4028 .... SI.04 8E56013 .. S3.83 cents. RAECO, Box 14, Reedville, Mass. 02137. Complete per. e 7411 . . . .. 244 7482 68c 74181 _ ..52.13 4029 .... 51.36 NE5618 . 13.93 sonal protec- Louder and Y Approxlmatell 1 7412 24c 7483 . ...68< 74182.. .. . 854 4030 504 NE5626 .. 53.83 PRECISION, Adjustable. solid state power supply. 15VDC tion. Push- longer sound. 135.5 decibels 7413 24c 7485 74190 . . 51.45 4033 . . . 51.67 NE5654 _ .. 1.45 sl.1l Leatherette case XM -484. Wt. 2 lbs. . . . 1 -1 7414 51.02 7486 .3I1 74191 . ., 51.45 4034 ....13.34 6E566V 51.28 at /2amps, regulated simultaneously with 10VDC at button Alarm. 0M -463. Wt. 2 7416 24c 74589 52.13 74192 _ .. S1.19 4035 .... 5136 NE567V .. 51.36 3amps unregulated, plus over 900 parts worth $400.00, 120 8M -482. Wt. 1 Ib. l 7417 ., 244 7490 485 74193 .. 51.11 4040 .... 51.60 4A709C4...434 7420 .. .. 244 7491 . 77c 74194 ...S1.n 4041 .90/ uA7119CV...43c transistors. Semiconductor characteristics. circuit 7421 244 7492 48c 74195 ... 51.I1 4042 82c u4710CA...364 diagrams included. New Cartrivision VTR electronic units. IN-LINE IÇ'S 7425 65c 7493 48c 74279 56c 4043 674 uA711CA_..37c DUAL ICs are 4044 uA723CA...60c These 7426 244 7494 77c 8797 95c 674 $19.95 plus $1.50 shipping. 50 cents for brochure. Madison En U.S. 7428 43c 7495 854 75150 ... S1.40 4046 ... S2.35 u4741CV...434 Made defects. Inc.. Box 369. 055. Madison, against lb. 7430 24c 7496 77c 4000 . ... 24c 4049 ., 524 oA747CA...684 Electronics Company. - - W guaranteed Sh wt. 7432 434 74100 1.24 4001 244 4050 52c 48748CV., 41c p9' Alabama 35758. with diagram. 7 -Se9- 7433 314 74107. 31c 4002 24c 4051 .... SI E4 MC14566. 1100 BCD to 290 'Type 7457 With 4052 LOW AS °/ 7437 244 74121 365 4006 51.50 .... 11.44 MC1458V .. 514 0ecoderlDrh'er. . melt 7438 . 244 74122. 434 4007 245 4053 .... 5144 MC3302P .. 854 displays. Oued 2-Input anode 7440 244 74123 784 4008 11.17 4060 .. 51.67 1.96309K .. 51.80 7400 common .... Gate. High 7441 ... 51.11 74125 39c 4009 644 4066 ... 904 1583246. 51.28 NAND 7R-435. The (iiV .i I E Poe clamped DARIFlOp 7442 .. 61c 74126 394 4010 64c 4071 .. 265 44780340 51.25 k diode- TYDe 7t73 Flly 7443 611 74132. 734 4011 24c 4072 ..264 u47806CU 51.25 I Stew 39c VCA Micro- Synthesizer Kit puts. 29c ter 7444 615 74141. ..944 4012 . 244 4073 ..264 u41808CU 11.25 VCO Ty-4J1. u1 TR -436. 7ONGDuel 7445 . 615 74145 4013 SOC 4075 264 417812C1.1 51.25 7474 51.16 ... Type Fllp -F1012 7446 77c 74150 5136 4014 .... 51.58 4081 ... 26c uA7815CU 81.25 VCF NOISE Type Low-noise Edge NOR2 Gets. Triggered s . 4082 7447 775 74151 .. 859 4015 ... 51.17 265 uA7818CU 51.25 delay 1 TR- 4367475 Le39c 7448 .. 854 775 4016 509 4502 .. 467824(0 11.25 29C 41344 74153. S116 2 Function Generator Type coded 7450 22c 74154 51 36 4017 SI 26 4511 1160 71028 53.50 TR-472. eMr. binary stores Type Hex dis- Temp Ribbon Controller low Dpower 79c Low noise. into. 32 pg. Using Manual siDDatlon 29c TR -477. Becode LED DISPLAYS Tp -473. t Type 7490 coded G Counter. Your RED. OREEN or YELLOW in a hand -held battery Type 7410 out- with 59" Chotee of Gets. Low decimal counter u NAND diode- divide. powered package Put Impedance. metrical 79c 0.3" High.... $1.90 es. 0.6" Nigh.... $3.50 ea. TR -439. clamped inputs 29c XAN72 RID C.A. XAN672 RED C.A. $48.95 plus shipping and insurance 6Ibs. TR -434. ------XANS2 GREEN C.A. XAN652 GREEN C.A. BIG 1 LB. The Perfect LOW COST INTRODUCTION XAN82 YELLOW C.A. XAN682 YELLOW C.A. BIG 5 LB. TO ELECTRONIC 0111174 RED C.C. XAN674 RED C.C. MUSICSYNTHESIZERS Surprise Resistor Kit XAN54 GIRTH C.C. XAN654 GREEN C.C. send for our FREE catalog Roc 3 °° Kit 08814 YELLOW C.C. XAN6B4 YELLOW Resistors, $i capaci- Over 400 pieces of PAIA .. 1/2. 1 watt SACS. Electronics, Inc. tors most wanted SILICON TRANSISTORS Box C -14359 Oklahoma City, Ok. 73114 - All color coded parts and hardware. 2'h lbs E8918. ..215 511.85iC 587536386 .Ibc 51360:C 7584868. .16c 51360/C xx -196. 5lbs. $1 990 RS-239. .. 99c MPS930 ... 16c 113.60/C 2N3640 .,. 214 517.851C 2N5089 ...154 313.60/C MP52222A 16c 513.60/C MPS3641 ..165 513.60/C 265129 ... 214 517.85/C COMPUTER. PERIPHERAL, TECHNICAL Reports; Project PNP MPS23694 . 169 513.60/C MP53643 ..164 51360/C 265133 ... 21c 517.851C 500 -ft- Supplies; Kits. Catalog 751A, 50 cents. EIS Lab, Box 738. MP52712 ..164 513.60/C 283645 .,. 21c E17.85/C 255134 ... 21c 517.85/C Hook -Up Transistors MPS2907A .169 513.60/C MP53646 ..16c 113.60/C 2N5137 ... 214 517.85/C College Park, Maryland 20740. Big 10 pc. kit. For 2143055 ... 99c 185,00/C 263904 ... 16c 513.60/C 2N5138 ... 21C 517.85/C Wire general. lo 8 hi- MP53392 .. 16c 113.60/C 283906 .. . 169 513.60/C 255139 . .. 21c 517.85/C Free CB RADIO, Scanners. Antennas. The best for less. For almost any 9an 8 audio. MP53393 .. 16c 513.60/C 264124 ...164 513.60/C 265210 ... 16c 513.60/C type of printed cir- 0753394 ..16c 113.601C 264126 ...16c 513.60/C 265457 ... 52c 144.20/C List. Capitol Sound, Box 3523, Des Moines. Iowa 50322. Germanium types. MP53395 ..169 51360/C 294401 ...164 51160/C PN5964 ...16c 513.60/C cuit or wiring pro- Untested- V. lb. 263563 ... 214 117.85/C 264403 ...16c 113.60/C MPFI02 ... 48c 140.80/C YOU WANT TO BUILD IT WE WANT TO HELP. WE SELL ject. 2 lbs. TR -445. 39C 58753565 ,-164 513.60/C 264410 ...16c 513.60/C MPSA13... 40c 534.00/C CONSTRUCTION PLANS with an Engineering Service. WW -579. _1.69 39c TR -444. -NPN. 39c MP53638 .-16c 513.60/C C106131 ... 559 550.00/C TELEPHONE: Answering Machines. Speakerphones. Car - 8 -T Blank Tape ELECTROLYTIC CAPACITORS phones, Phonevision. Touch Button Dialers. TELEVISION: Three 60 -M1n. Famous manufac- - Radial Lead - - Axial Lead - - Asini Lead - VTR, 1" Color TV Set. PONG. $25.00 Camera, COLOR turer s high Dual- lufdr50v....III 7.70/C 47ufd /25, 17c 511.20 /C PROJECTION TV. HOBBYIST: Electron Microscope, $75 II Cassettes 'l iEy low priced 1488 /50, 8c S 5.40 /C 2.2468 /504 , 129 7.80 /C 100ufd /164 I7c 111.202 software programmable computer. BROADCAST: Special Pkg. / 3 quality tapes V2 lb 2.2564/504 ... 89 S 5.40 /C 3.3ufd /354 .. 12c 7.90/C 100ufd /254 .. 20c 513,301C cassette record- TA -854. . . & 5 5.60 /C 3.3958/50, 12c 100ufd _ . 29c 519 70 3.348d/509 .. 8.30/C /504 /C Effects Generator, Chroma Key. Audio Board. DA's. ing tapes. 60- Min. 40 -Min. B9c 4.7459 /254 ... 84 S 5.40 /C 4.70d /35, , 12c 7.90/C 220464/16, , 20c 513.30 /C V2 TA -855. 10484/25,.... 8c 5 5.70/C 1004716v... Ilc 7.70/C 220664/259 259 520.00 /C COURSES: Telephone Engineering $52.00, Detective each Ib. 80 -Min. 99c 10664 /504._. 10c S 6.60/C 10146d /25v ..125 8.30/C 330658/164 294 520.00 /C Electronics $29.50, IC Engineering $65.00, PLUS MUCH TA -979. _ 99c 22ufd /254....9/ S 6.10/C l0ufd /504... 14c 9.60/C 3309fd/25v . 329 121.60/C 12c 470ofd/164.. r sub - 2241d/504... 124 S 8.50/C fluid /16v... 8.30/C 324 521.60/C MORE. NEW Supe Hobby Catalog PLUS year's 50 -Pc. 1 Amp Silicon 100r9d /6.34 ..9c S 6.30/C 27,74/259. 13c 8.70/C 47041d/259 .. 374 535.40/C scription to Electronic News Letter AIR MAILED $1.00. Don Rectifiers 1006fd /169 , 119 5 7.30/C 33684/16,... 12c 8.50/C 1000684/16, 39c 526.60/C Diode Kit 1 Amp Epoxy Type 100064/25, 13c S 9.20 /C 33664/25,... 14, 9.60 /C 1000u1d /254 56c 538.20/C Britton Enterprises. 6200 Wilshire Blvd.. Los Angeles. Polarity is un- 47454/16,. 149 960/C 220004/169. 62, Pkg./S. 4 a:. 542.00/C Calif. 90048. marked but easily REED RELAYS identified with DI-028 50 PIV IN4001 39c DISC CAPS FREE CATALOG. Ultrasonic Devices, LEDs. Transistors. ohm meter. 200 - 6 AMP PST N.O. DI-029 100 PIV IN4002 39c 100155/500, 4, 5 6.09/2( Ply rated, th lb. - 01,84 /500,. 64 S 8.55/20 CONTACTS IC's. Keyboards. Digital Thermometers, Unique Compon- DI-030 200 PIV IN4003 39c 2200/500v . 44 S 6.09/2[ - 01ufd60v . 3c 5 4.05/7( 01.091.._ 69C 01-031 400 PIV 194004 39c 470pí /5009. 44 S 6.09/20 5 v. Coil .. 51.70 5125 /C ents. Chaney's. Box 15431, Lakewood. Colo. 80215. 022ufd/25v. 34 5 7.73/2[ - 1000pf /500v 49 5 6.22/20 6 V. Coil .. 51.70 1125/C 047488'75,. 5' S 4.73/2C 220076/5001 4, 9 6.22/00 124. Coil.. SI 70 1125/C SEMICONDUCTOR AND PARTS Catalogue from the semi- Switching 1458125, 85 810.57500 470070/500, 24V $1.70 /C 45 5 5411K Coil 5125 conductor specialists. J & J Electronics, Box 1437, Diodes LED'S 2V SILICON DIODES Winnipeg. Manitoba. Canada. U.S Inquiries. Pkg 10 1114148 - 10mÁ 1844148. 401/10 53.50/C 164004 70010 15.95/C HARDWARE for no current ap- Gallium phos- 1614001 .. 644/10 15.50/C 164005 .. 82,10 17.05/C 2.561/4 Screw 995/C 17,20/88 ELECTRONIC igniitìon: Pointless. Transistor, Capacitor. plications 10 mA- 154002..669/10 55.61/C 1N4006 - -90/110 1773/C 99c cphide. Large red. 2 -56 1/2 Screw /C 17.65/M 10 75 PIV '64 lb 164003 681/10 55.78'C 16407 .99/110 58.59/C Vapor inductors, Auburn Sparkplugs. Information Cents high quality LEO. 470 1/4 Screw .. 55c /C 5360 /M XM -382. 59c _ 1/4 470 1/2 Screw 60c /C 54.05/M Anderson Engineering, Epsom, N.H. 03234. Wt lb. Pkg /5. yo ZENER WATT DIODES 6-32 1 r4 Screw 65c /C 54.40/M PL -233 59e 11152260 3.34 .155 511 /C 161523613 73, 15, 111 /C 632 1/2 Screw 751/C 14.85/M TV PING PONG game. Plays through your set's antenna 9N522713 3.6v 15c $11 /C 5852378 832 3/8 Screw .. 909 /C 55.85/M 8.2, 15, 111 /C terminals: Plans $3.25. ARS SYSTEMS, Box 1922. Sunny- SCR 1652288 3.9v . 154 511 /C 16152388 8.7, IS, 511 /C 2 -56 Hex Nut . 584/C 13.60/88 1NS22913 4.3v . 15c SII /C 1652398 9.1v 15, S11SC 470 Her Nut 559/C 33.75/88 vale, CA 94088. Assort- 11452308 439 15c 811 /C 1852408 10v.. 15c 111 /C 6-32 Hex Nut 60c /C 1000 /M A

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www.americanradiohistory.com NEW PRODUCTS LINEAR IC's MICROPROCESSORS H-TO-5 N-DIP M-MINI-DIP D-CER-DIP K-TO-3 1-9 10up LM114H $3.00 LM311D .90 LM711CH .90 8008 23.90 22.90 1702 17.00 PROTO BOARDS LM300H 1.20 LM311M 1.75 LM711CN .90 8080 59.00 39.90 P4101 5.50 LM300N 1.20 LM311N 2.00 LM715CH 3.50 MC680O 89.00 79.00 P8101-2 6.00 Build & test circuits as fast as you think) LM301AH 50 LM312H 2.50 LM715CD 4.60 P1101A 2.20 2.10 P8102 4.00 P9100 10 IC cap breadboard kit, 4.5 x 6.0 x 1.35" $19.95 LM301AM .80 LM318H 1.49 LM723CH .60 P1101A1 3.50 3.30 P8102-2 4.00 P13101 10 14 -DIP cap, 5-way post, 940 solderlos, $29.95 LM301AN 1.10 LM318M 2.40 LM723CN .65 P2102-1 3.90 3.00 P8111 5.60 tie points, 5.8 x 4.5" LM301M .90 LM324N 1.90 LM723N .70 91L02 3.90 3.20 P8111-2 6.00 P8102 12 14 -DIP cap., like P6101 with 1,240 tie $39.95 LM301H .90 LM331N 2.20 LM725CH 2.00 91L02-1 3.90 3.20 9102PC 4.00 points, 7.0 x 4.5" 1M3020 3.50 LM339N 2.90 LM725CD 5.00 PB103 24 14 -DIP cap., 4 5-way posts, 2,250 tie $59.95 LM3025 1.30 LM320-5K 2.90 LM733CH 1.40 COMPUTER MOS-LSI points, 6.0 x 9.0" LM302H 1.40 LM320-5T 2.50 LM733CD 3.50 BIPOLAR PB104 32 14 -DIP cap., 3060 solderless tie points, $79.95 1M304H 1.20 LM320-12K2.90 LM733CN 1.30 INTERFACE MEMORY LM305H .85 LM320-12T 2.50 LM741CH .40 8.0 x 9.76" 0M88205 2.40 LM305AH 1.05 LM336K 2.40 LM741CD 1.25 DM8820AN 6.90 C3101 6'60 1403A 4.00 LM3055 1.00 LM340-05K 2.60 LM741CM .39 2.40 P3101 4.90 DM88305 C3101A 55.80.30 1403AN 3.80 PROTOCLIP LM306H .95 LM340-0614 2.60 LM741CN .70 DM88315 5.20 1404AH 4.50 F power- on /hands.off LM307H .60 LM340-138K 2.60 LM747CH .70 6.00 P3101A L, LOGIC MONITOR by Id DM8832N 7.30 1404AN 2.90 leans) LM307M .95 LM340-12K 2.60 LM747CN .90 N8T26B 4.40 IM6501CDE I405Á Simultaneously displays leads up from PC boertl IM5501CPE 4.00 static and dynamic loo- LM3075 1.50 LM340-15K2.60 LM747CD 2.50 9600PC 1.30 1,3 1406 8.40 face for fest trouDls- LM308H .86 LM340-18K 2.60 LM748CM .55 MM5560D 5.3 - stetes of DTL, TTL, 9601PC 1.20 14071 8.40 Moodng. LM308AH 5.00 LM340-24K 2.60 LM748CN .55 MM5560N 5.80 E HTL or CMOS DIP ICs. PCI: 14-pin $4.50 9602PC 1.96 5.80 1506 3.00 I_ Pocket size. LM308D 2.00 LM555CM .70 LM777CH 2.15 DM8599N p_ E84.95. PCi6 16 -Pin 4.75 9614PC 2.30 93403PC 6.80 1507 3.00 LM308M 1.20 LM556CM 1.30 LM777CM 2.10 9615PC 2.40 1602 33.00 LM309H 1.75 LM567CM 1.70 LM3046CN .95 9616PC 5.00 P2101 5.00 SOCKETS & BUS STRIPS LM309K 1.60 LM709CH .45 LM3054CN 1.50 9617PC 3.50 1024-BIT P2101-1 5.50 Plug -In, wire, test, modify or expand without patch LM3101-1 1.50 LM709CN .45 SG4501T 2.40 9620PC 4.00 NChannel RAM P2101-2 4.90 cords or soldar. Snap together to form breadboard LM310M 1.80 LM710CH .90 SG45015 2.40 9621PC 4.00 P2111 5.80 LM311H 1.20 C2102 5.00 needed. LM710CN 90 LM5000K 7.50 75107 P-2102 2.85 P2111-1 6.00 PN /Description L. Hola'to -Hob Term'Ie Price 7510785 2.60 C2102-1 5.00 P2111-2 5.90 0759S Socket 6.5" 6.2" 110 $12.50 C-MOS 7510865 2.30 P-2102-1 3.90 P2112 5.00 07598 Bus 6.5" 6.2" 20 2.50 1-9 10up 1-9 10up 1A 10up 751O9N 2.20 C2102-2 6.00 P2112-2 6.90 QT475 Socket 5.3" 5.0" 94 10.00 4000AE .26 .22 4023AE .26 .22 4053AE 1.34 1.33 761105 2.20 P-2102-2 3.00 P2401 9.90 QT47B Bus 5.3" 5.0" 16 2.25 4001AE .26 .22 4024AE 50 .88 4066AE 2.68 2.00 75115N 2.25 P-2102A 8.00 P2405 9.70 i OT35S Socket 4.1" 3.8" 70 8.50 4002AE .26 1.86 .22 4025AE .26 .22 4056AE 2.43 75138N 2.95 P-2102A-2 9.50 2505K 3.30 QT35B Bus 4.1" 3.8" 12 2.00 4004AE 6.83 5.82 4026AE 3.72 3.70 4060AE 1.60 1.25 75150N 3.10 P-2102A-4 6.00 2612K 4.00 OT18S Socket 2.4" 2.1" 36 4.75 4006AE 1.35 1.34 4027AE .60 .50 4066AE .90 .72 75154N 4.10 2521V 2.50 QT12S Socket 1.8" 2601-1 4.00 1.5" 24 3.75 4007AE .26 .22 4028AE .98 .90 4069AE .38 .34 752085 2.70 2601-21 11.40 2525V 3.50 OTBSSocket 1.4" 1.1" 16 3.25 4008AE 1.79 1.78 4029AE 1.27 1.16 4070AE .65 .54 75234N 2.50 2533V 7.90 5 5ç OT7SSOcket 1.3:: 15" 14 3.00 26028 3.80 4009AE .60 .50 4030AE .44 .37 4071AE .26 .22 76450N 1.25 2602-18 4.40 2803PC 4.00 4010AE .69 .50 4033AE 3.01 3.00 4073AE .34 .30 75451N 1.00 2602-28 4.00 2804PC 4.00 4011AE .26 .22 4035AE 1.27 1.16 4076AE 1.681.48 75452N 1.00 MK4102P 11.40 2807PC 2.70 7400N TTL 4012AE .26 .22 4040AE 1.49 1.25 4081AE .26 .25 75453N 1.00 7552-1CPE 6.00 2808PC 4.00 4013AE .47 .40 4041AE A06 4.05 4507AE .60 .55 7520 SERIES 7552-2CPE 6.00 TMS3114J 9.40 7400N $.13 7443N .95 74104N 1.20 74165N 1.30 4014AE 1.49 1.25 4042AE .75 .64 4508AE 2.30 2.20 SENSE AMPS TMS4033JL 9.00 TMS3120JC 7.00 7401N .16 7444N .72 741065 .60 74166N 1.30 4016AE 1.26 .90 4043AE .60 .50 4510AE 1.98 1.46 7520N 4.00 TMS4033NL 4.20 TMS3120NC 6.00 7402N .14 7445N ,90 74107N .30 74170N 2.60 4016AE .56 .45 4044AE .60 .50 4616AE 1.98 1.46 7521N 2.00 TMS4034JL 9.00 TMS3133NC 7.50 7403N .16 7446N .90 741095 .90 74173N 1.50 4017AE 1.20 1.00 4047AE 3.54 3.53 4518AE 1.28 .98 7522N 4.25 TMS4034NL 4.20 3341ADC 8.00 74045 .19 7447N .77 741105 .72 74174N 1.10 4018AE 1.49 1.25 4048AE 1.43 1.42 4520AE 1.28 .98 7523N 1.75 TMS4035JL 9.00 3341APC 7.00 7405N .20 7448N .80 74114N .93 74175N 1.20 4019AE .52 .44 4049AE .52 .50 4528AE 2.30 2.20 7524N 2.00 TMS4035NL 4.20 3347DC 5.80 7406N .29 7450N .16 74118N 1.52 74176N 1.25 4020AE 1.49 1.26 4050AE .52 .50 4585AE 2.09 2.08 7525N 4.50 3347PC 4.60 7451N .16 .45 4102 7407N .29 74121N 74177N 1.40 4021AE 1.34 1.25 4051AE 1.341.13 4901AE .43 .36 TWO -PHASE MM 4.95 7408N .18 7463N .16 74122N .45 74180N .73 4022AE 1.11 1.00 4052AE 1.34 1.33 4911AE .43 .36 MOS CLOCK 7552 4.95 7409N .20 7454N .16 74123N .70 741815 3.00 MM404H 12.00 7552-1 5.40 DRIVER MM405H 23.00 7552-2 7410N .18 7460N .16 74125N 50 741825 .70 MH0026CN 5.50 5.50 7411N .26 7470N .30 74126N .60 74184N 2.00 MM406H 6.50 MM4055D 12.00 7412N .33 7472N .30 741285 .90 74185N 2.20 PREMIUM QUALITY DECODED MM407H 6.50 MM4056H 9.70 7413N .58 7473N .37 74132N 1.00 74188N 4.80 READ/WRITE MM451H 11.40 MM4057D 13.00 1.06 RAM MM454F 18.00 MM5025N 7414N 7474N .32 74136N .95 74190N 1.20 COMPONENTS P1103 20.00 7416N .28 7475N 50 74141N 1.20 741915 1.20 5.90 MM500H 2.00 MM5026N 20.00 7417N .33 7476N .32 741465 1.00 74192N 1.10 We've been buying and selling top quality 2524V Recirculating MM606H 3.20 MM5027N 20.00 7420N .17 7480N .59 74147N 2.40 74193N 1.00 512 Bit Dynamic MM507H 3.20 MM5055N 5.50 74215 .33 7481N 1.18 74148N 1.80 74194N 1.15 components for nearly ten years. Our Shift Register MM550H 5.90 MM5056N 5.50 7422N .50 7482N .89 741505 1.00 74195N .80 annual volume exceeds $3 million. We 1 -24 2.40 MM551 H 5.60 MM6057N 5.50 7423N .50 7483N ,65 741515 .80 74196N 1.70 25 up 2.30 MM555H 5.60 MM5O58N 5.50 7425N .34 74845 3.00 741625 1.40 74197N .80 handle only original parts, from the 7426N .25 74855 1.20 741535 1.00 74198N 1.76 world's leading manufacturers and our 7427N .31 7486N .35 74154N 1.40 74199N 1.40 customers include some of the largest IC SOCKETS 7428N .50 7489N 2.25 74155N 1.00 74200N 5.60 SOLDER -TIN DIP WIRE-WRAP GOLD 7430N .20 7490N .48 74156N 1.18 74221N 1.70 and most quality- conscious companies. PIN 1 25 100 PIN 1 -24 25 100 TEFLON TO-5 7432N .24 7491N .90 741575 1.00 742515 2.00 Now you can take advantage of our -24 7433N .60 7492N .55 741585 1.20 74278N 2.95 8 .21 .19 .17 14 A5 .41 .37 3 PIN .55 EA 7437N .35 7493N .58 74160N 1.30 74279N .90 component buying skills and power 14 .25 .22 .20 16 .54 .49 .44 4 PIN .65 EA 7438N .33 7494N .80 74161N 1.20 74293N 1.00 and select from a broad range of 16 .28 .25 .23 6 PIN .90 EA 7439N .38 7495N .80 741625 1.40 74298N 2.20 24 .67 .61 .55 SOLDER - GOLD 8 PIN 1.10 EA 74405 .16 7496N .78 74163N 1.40 advanced circuits. 28 .88 .80 .72 10 PIN 1.40 EA 7441N .95 74100N 1.00 74164N 1.30 36 1.09 .98 .89 14 .34 .28 7442N 50 40 1.24 1.12 .92 16 .37 31 WAVEFORM GENERATOR KIT HIGH SPEED TTL LEDs 74H00N $.33 74H20N .33 74H53N .36 74H 73N 90 Here's a highly v rsetlle lab In- 74HO/N .25 74H21N .33 74H54N .36 74H 74N 87 strument at a fraction of the .125" dia. .160 ".die .200" dia. 74H 02N .30 74H22N .33 74H55N .36 74H 76N .90 EXAR cost of conventional unie Kit 74H04N .33 74H 305 .33 74H60N .36 74H1015 .BO XR205K includes 2 XR205 IC's, data & $25.00 applications, PC board (etched ._. 74H05N .33 74H40N .36 74H615 .36 74H 102N .80 1111V- ou _ and drilled, reedy for assembly) - 74H085 .40 74H 505 .36 74H625 .36 74H103N 1.10 and detallad Instructions. 209 RED .25 216 RED $.25 220 RED 5.25 74H10N .33 741-1515 .36 74H715 .80 74H 106N .95 YELLOW 74H11N 209 YELLOW .35 216 YELLOW .30 220 .30 .33 74H52N .36 74H72N .74 209 GREEN .36 216 GREEN .30 220 GREEN .30 LOW POWER TTL 1 -AMP RECTIFIERS 1 INTERSIL 8038 LOW PROFILE 74LOON 5.31 741.105 .33 74L515 .34 74L90N 1.62 10 100 1000 74L02N .33 74L2ON .33 74L73N .69 74L93N 1.74 PRECISION WAVEFORM 154001 1.00 7.00 60.00 74L03N .39 74L42N 1.49 74L74N 50 74L95N 1.62 GENERATOR & VCO 1N4002 1.10 8.00 70.00 74L04N .33 For simultaneous si e, aguare 154003 1.20 9.00 80.00 226 RED $.25 5053 RED $.35 MV50 RED $.30 74LS and triangular waveforms <001 154004 1.30 10.00 90.00 226 YELLOW .30 5053 YELLOW .40 Hz to 1MHz. 154005 1.40 11.00 10500 226 GREEN .30 5053 GREEN .40 216 MV5024 74L800 .46 74LS27 .50 74LS112 .58 74LS170 5.80 - Part No. 1 -9 10u 154006 1.50 12.00 110.00 226 ORANGE .30 5053 ORANGE .40 5053 - MV5053 74LS01 .58 74LS30 .46 74LS113 92 74LS174 2.20 8036CLPLJ 3.90 3.70 154007 1.60 13.00 120.00 74LS02 .46 74LS32 .50 74LS138 206 74LS175 2.42 74LS03 .50 74LS38 .46 74LS139 206 74LS181 7.00 DISPLAYS 74LSO4 .50 74LS61 .60 74LS151 1.92 74LS194 2.40 HIGH VOLTAGE 74LS08 .46 74LS54 .48 74LS153 1 92 741_5195A 2.40 HYBRID POWER 74LS09 .58 74LS55 .58 74LS157 1.68 74LS 196 2.76 AMPLIFIERS TRANSISTORS LITRONIX 74LS10 46 74LS73 .58 74LS158 1.68 74LS251 2.06 BU204 3A 1300V 54.14 4.95 DL80 RED 6.00 74LS11 .46 74LS74 .58 74LS160 3.O6 74LS253 2.42 SI-1010G 10W $6.40 BU205 3A 1500V DL81 RED 6.00 74LS 15 .58 74LS76 .92 74LS161 3.06 74LS257 2.06 SI-1020G 20W 9.90 BU206 3A 1700V 5.94 DL10 RED 6.00 74LS20 .46 74LS78 .92 74LS162 3.06 74LS258 2.06 SI-1030G 30W 18.70 BÚ207 6A 1300V 5.85 DL10A RED 4.00 74LS21 .58 741_5107 .92 74LS163 2.90 74LS260 .58 SI .1050E 50W 24.90 BU208 6A 1500V 6.93 6A 1700V 8.64 DL101 RED 4.90 74LS22 .58 74LS109 .92 St-105oG 50W 24.90 BU209 OPCOA DL57 RED 9.90 SCHOTTKY TTL SLA1 RED 2.25 DL61 RED 12.00 SLA11 GREEN 3.50 DL33 RED 4.00 74SOON $.44 745515 .80 74S140N .80 7431895 4.40 PICO -PAC POWER SUPPLIES 0L44 RED 6.00 74502N .60 745645 .80 7451515 2.20 7451945 3.30 DL402 RED 4.00 745035 .75 74S74N 1.20 7451535 3.40 7451955 3.30 ADTECH XCITON DL701 RED 3.40 74504N .55 74505N 6.10 745157N 2.40 74$2515 2.20 DL704 RED 2.26 743085 .80 743865 2.50 7451585 2.20 7432635 2.40 Output XAN72 RED 2.00 XAN52 GREEN 2.00 DL707 RED 2.35 745105 55 7451125 1.00 7481605 3 90 7432575 2.40 Model No. Vdc Amps 1-4 5 up DL747 RED 2.50 743115 65 7451135 1.50 74S161N 4.70 7452585 2.40 74520N 65 7451325 3.60 7451745 3.30 7482605 1.20 APS5-3 5 3.0 1 -9 10up 745305 80 7431335 .80 7431755 2.90 7432805 5.70 THE SMALLEST APS12 -1.6 12 1.6 DL747 REO 2.50 2.40 74.5325 80 7451385 2.20 7451815 8.40 74$2895 4.00 AC /DC POWER APS75 -1.5 15 1.5 $29.95 $28.60 74540N 65 7451395 2.20 SUPPLY EVERI APS24-1 24 1.0 EP 9125 Only 1.70"01.00" APS28.0.8 28 0.8 9 -DIGIT DISPLAY 9300 SERIES o 0.85 ", output pre - $7.90 ELECTRONIC 9300PC $1.00 9318PC 2.30 9366PC sat %, 9 models: APS5 -6 6 ARRAYS 1.75 93L18 3.50 APS12 -4 12 4 1/8" Character Ht. 9301PC 1.20 9321PC 1.20 93L00 1.50 93L21 1.50 5 140 Thin PC APS75 -3 15 3 $48.45 Compact, EA1500AJ 9304PC 1.50 9322PC 1.30 93L01 1.60 8 115 $46.05 93L22 1.80 APS24 -2.2 24 2.2 Pkg., Wide Viewing 1-24 $21.00 9306PC 6.90 9324PC 2.00 93L08 3.20 2.80 10 100 93L24 APS28 -2 28 2 Angla 25 16.80 9308PC 2.50 9328PC 2.50 93L09 1.80 93L28 3.70 12 90 100 14.00 9309PC 1.60 9334PC 2.95 93L10 93L34 4.00 15 70 280 EA 1500ASJ 9310PC 1.50 9338PC 3.30 93L11 4.20 93L38 4.20 18 50 5 10 OPTOISOLATORS APS5-10 1-24 $16.00 9311PC 2.30 9340PC 5.00 93L12 1.80 93L40 20 35 APS 12-7 12 7 MONSANTO LITRONIX 6.50 25 14.40 9312PC 1.20 9341PC 4.10 93L14 1.70 22 25 15 6 I L1 1.30 1L74 1.35 93L41 6.50 APS15-6 $72.25 $68.65 100 12.00 9314PC 1.30 9342PC 1.15 93L16 3.20 93L60 3.00 24 15 APS24-5 24 5 M C T 2 1.35 11_12 1.40 0.074D74 1.75 9316PC 1.50 9360PC 1.75 93L18 3.50 93L66 2.70 $39.80 each APS28-4 28 4 1L16 1.80 ILQ74 3.40 STANDARD MICROSYSTEMS AUDIO AMPS Prices effective through January 31, 1976 postage handling. C SÈ PRICE Minimum order: $10.00. Add $1.00 to cover and lifornie esIdents add 6% sales tac. TYPE V W COM2502 $13.20 $10.60 SEND CHECK OR MONEY ORDER TO: COM2502P 8.00 6.85 LM352 6-15 1.15 8 1.60 COM2017 13.20 10.60 TAA611B12 6-15 1.15 8 1.60 COM2017P 8.00 6.85 TAA621Al2 6 -27 1.40 8 2.00 COM2502H 25.00 20.00 TAA641811 6-15 2.20 4 3.00 COM2017H 25.00 20.00 TBA800 5.30 4.70 2.20 COM2601 30.00 24.00 TBA810AS 4-20 2.50 4 3.00 COM5016 12.00 9.60 TBA820 3 -16 0.75 4 1.70 Mail order P.O. Box 2208P, Culver City, CA 90230. Phone order (2131 6414064 KR2376-ST 20.00 17.50 TCA830 5 -20 2.00 4 2.20 Visit our Electronic Shop: 11080 Jefferson Blvd., Culear City, CA KR3600-ST 20.00 17.50 TCA940 6 -24 6.50 8 4.40 (Studio V illaoe Shopping Cantar) NMX5010 12.00 9.60 Prices may vary at over t he. counter locations. CAL1022 60.00 52.00 -

CIRCLE NO 8 ON FREE INFORMATION CARD JANUARY 1976 113

www.americanradiohistory.com SURPLUS, Receivers, Transmitters, Components, test ELECTRONIC ROULETTE: "Wheel of Fortune" shown in equipment. Catalog free. E. French, 10 Afton, Aurora, October's Popular Electronics. Complete kits, $24.95 with Illinois 60538. PLANS AND KITS same day shipments from Hosfelt Electronics, 224 Opal TV TECHNICIANS, SERVICEMEN, HOBBYISTS-Vista Blvd., Steubenville, Ohio 43952. Model 740 Digital Crosshatch Generator. Compact crystal NEW FROM EICO- Listen to official FCC -Licensed back- divider for lowest -priced ultra -stable 5x7 crosshatch or 56 ground music (SCA) on your FM radio dot patterns. AC powered. $31.95 complete kit; $41.95 as- without com- mercials. EC5000 Kit. $12.95 Postpaid. M sembled. Postpaid in USA, Canada. Information available &K Electronic AMAZING ELECTRONIC Corp., 135 -33 Northern Blvd.. Flushing. N. Y. 11354. free. Photolume Corporation, Dept. PE -16, 118 East 28th Street. New York, New FREE CATALOGUE KITS. COMPONENTS. Audio equip- V. PRODUCTS York 10016. ./í/ LASERS SUPER POWERED, RIFLE, PISTOL POCKET SEE IN DARK . Pilo ment. Sinclair Kits. radio parts. TE Gladstone Electronics. CHNICAL, DEBU0GING UNCRAMBLERS. GMNT TESLA . STUNWAND. TV 1736 Avenue RD.. Toronto. Canada, M5M 3Y7, U.S. DIS RUPTOR . ENERGY PRODUCING, SCIENTIFIC DETECTION, ELECTRIFYING, EMEAL, ULTRASONIC, Ce, AFRO, AUTO ARID MECH DEVICES, HUNDREDS CALCULATORS Inquiries. MO RE . ALL NEW PLUS INFO UNITO PARTS SERVICE. NEW Capacitance Meter reads picofarads like ohmmeter INFORMATION UI8 UYliftd reads ohms. Two I.C. battery circuit. Schematic. details CAT 8106 51 Box 626 Lord letten P2. Amherst, N.H. 03031 TEXAS INSTRUMENTS CALCULATORS DISCOUNT HOT $2.00. C. Hall. Box 692. Addison, Texas 75001. LINE Toll Free (800) 638 -8906. Phone us long distance free ELECTRONIC game kits. Creamed Chicken. ESP. LEDice, for the low discount price on the Texas Instruments Calcu- others. Send Stamp. NBL -E, Box 1115. Richardson. Texas lator of your choice: SR -50A. SR -51A, SR -16. TI -2500 Il, TI- 75080. BURGLAR ALARMS 1500. TI -2500, TI -2550. TI -5050. All of the great new Texas Instruments models. Capital Calculator Company. 701 East SCIENCE kits for youngsters, information: Schubel & Son. Box 214848-Y. Sacramento. CA 95821. Gude Drive. Rockville. Maryland 20850. The discount super BURGLAR ALARM dialing unit automatically calls police. market for top brand name calculators. Mail and phone TESLA COIL -40' SPARKS! Plans $7.50. Information 75 $29.95. Free literature. S &S Systems, 5619 St. John, orders accepted. BankAmericard and Master Charge cents. Huntington Electronics. Box 2009 -P. Huntington, Kansas City. MO 64123. accepted. Conn. 06484. PRESSURE sensitive miniature cable for burglar alarm systems. Place under carpet in any contour for intrusion detection or secret switching. $4.95 for twenty feet, Cable Switch Corp.. Box 72 -PE. West Long Branch. NJ 07764. BURGLAR -FIRE alarm supplies and information. Free catalog. Protecto Alarm Sales. Box 357 -G. Birch Run, Michigan 48415. BURGLAR -FIRE ALARM Systems and information- Free Catalog. Vancor Security Systems. Box 438, Boston. Mas- INTEL 8080 CPU $89.00 TRANSISTOR SPECIALS C/140S (DIODE CLAMPED) 8008 BIT MICRO PROCESSING 2N3585 -NPN Si 10 -66 5 95 74CO2- 26 4012- .24 4025- .24 sachusetts 02144. CHIP (with Data Book) $29.95 2N3772 -NPN Si TO -3 $1.80 74C10- .30 4013- .45 4026 -1.90 PROTECT your family against burglary -fire with a double 2102-2 1024 BIT RAM $2.95 2N490 PNP Si TO-3 $ 85 74C157-1.75 4015-1.24 4027- .55 5202A UV PROM $12.50 2N6517 NPN Si TO-92 4$1.00 4001- .24 4016- .50 4028- .95 duty alarm. Only $8.95, guaranteed. Olivoco. 3737 Willett MM5203 UV PROM 2N5086 PNP Si TO-92 4$1.00 $12.50 .24 4017 .49 Ave., Bronx, N.Y. 10467, 5204-4K PROM $24.95 2N4898 PNP TO-66 $ .60 4002- -1.15 4030- 1702A -UV PROM $15.95 25404 PNP GE TO-5 5 $1.00 4006-1.35 4018 -1.24 4035 -1.50 2N3919 NPN Si TO-3 RF $1.50 4007- .24 4019- .50 4042- .75 MINIATURE TRIM POTS BOURNS 3009 MPSA13 NPN Si TO-92 3-$1.00 4009- .50 4022 -1.24 4046 -2.75 HIGH FIDELITY 5K, 10K, 50K. 100K, 200K 2N3767 NPN Si T0-66 .70 4010- .50 4023- .24 4047 -3.50 Si TO-18 5 $1.00 100, 500 2N2222 NPN 4011- .24 4024- .95 4050- .49 253055 NPN Si TO-3 $ .80 $75 ea. 3/$2.00 4055 -1.95 2N3904 NPN Si 10-92 551.00 MULTI -TURN TRIM POTS 2N3906 PNP Si 10-92 5$1.00 FCO 810 OPTO-ISOLATOR ..5.80 DIAMOND NEEDLES and Stereo Cartridges at Discount Similar to Bourns 3010 style 3,16' 65" 2N5296 NPN Si 10-220 $ .50 prices for Shure. Pickering. Stanton. Empire. Grado and 2N6109 PNP 10-220 144 50. 100. 2000. 10,000 ohms $1.50 Si 7 POLE SINGLE THROW TO -5 P, 2N3866 NPN Si TO-5 Si RF..,.$ .75 ADC. Send for free catalog. LYLE CARTRIDGES. Dept. 5 -30V, LIGHT ACTIVATED SCR's 2N3638 NPN Si TO-5 ....5.$1.00 MINITURE ROTARY SWITCH Box 69, Kensington Station, Brooklyn. New York 11218. 2N2218A NPN Si TO-5 4 51.00 LOW CURRENT $1.15 TO -18 200V lA $1.75 SAVE 50 %. Build your own speaker systems featuring PRINTED CIRCUIT BOARD CAPACITORS DO -33 -A 3 DIG. LED Full Wave Bridges Norelco, Eminence and CTS. Famous brands from world's 41/2"0 61/2" single sided epoxy board, 35V at .47 OF TANT 5 /$1.00 ARRAY READOUT ...$1.35 PRV 2A 6A 25A largest speaker factories at lowest wholesale prices. Write 1/16" thick, unetched 35V at 6.8 OF TANT 31$1.00 MAN -1 READOUT ...$1.75 OF 40 $.50 ea. 5/$2.20 25V at 33 TANT ...$ MAN -3 READOUT ..,91.00 200 .95 1.25 $3.00 for free catalog of speakers and electronic accessories. 35V at .68 OF TANT 541.00 MAN -4 READOUT ..41.30 1901 VECTOR BOARD .1" SPACING 20V at 150 OF TANT ..$ .40 400 1.15 1.50 $4.00 McGee Radio & Electronic Corp.. McGee Street, MAN -7 READOUT ..41.25 4.5" x 6 "SHEET $1.50 6V30 OF TANT 541.00 600 1.35 1.75 $5.00 Kansas City, Missouri 64108. 200V 4.7 OF ELECT , .. ,5.30 DL747 $3.50 2N5460 P FUT $ 45 SPEAKERS. build $200 pair for $40. Attractive fool -proof TIS 73 N FET 45 4 WATT IR $ FPA 711 -7 LEVEL DIODE ARRAY design. Plans $2.00. Blllman, 101 Valley View, Coquille. OR 254891 UJT LASER DIODE $7.95 $ 45 OPTICAL TAPE READERS $5.95 97423. ER900 TRIGGER DIODES $441.00 CD201 100x100 CHARGED CD 110 LINEAR 256 X1 BIT SELF SCANNING 2N6028 PROG. UJT. S 50 COUPLE DEVICES $145.00 CHARGED COUPLED DEVISE, WITH MM MOS SERIES DATA $125.00 VERIPAX PC BOARD MM 1402-3.75 MM5018-4.75 MM5060-4.95 WANTED SANKEN AUDIO POWER AMPS This board Is a 1 16" single sided pa- MM1403.3.75 MM5050-3.75MM5061-4.30 Si 1010 G 10 WATTS $ 6.90 per epoxy board, 41/2- 6To ". DRILLED MM1404-3.75 MM5055-4.00MM5260-2.95 and ETCHED which will hold up to 21 MM5013-7.75 MM5056-4.00MM5555-6,25 Si 1020 G 20 WATTS $3.95 single 14 pin IC's or 8. 16 or LSI DIP MM5016-3.50 MM5057-4.00 MM5556-6.25 Si 1050 G 50 WATTS $24.95 QUICKSILVER, Platinum. Silver. Gold. Ores Analyzed. IC's with busses for power supply con- MM5017-4.75 MM5058-4'.95 nector. $5.25 LINEAR CIRCUITS Free Circular. Mercury Terminal. Norwood. Mass. 02062. TTL IC SERIES LM 309K 5V to REGULATOR 51.35 MT -2 PHOTO TRANS 5.60 74L00- .26 7476- .35 723 -40 +40V REGULATOR 5.54 RED, YELLOW. GREEN OR AMBER 7400- .14 7480- .48 301/748 -Hi Per. Op. Amp $.28 LARGE LED'S 5.20 EA. 7401- .15 7483- .75 307 OP AMP $.28 MICROTREK® 14 PIN DIP SOCKETS 3.40 7402- ,15 7485 -1.05 CA 3047 - HI PERFORM OP AMP 5.95 16 PIN DIP SOCKETS 5.50 7403- .15 7486- .34 CA 33089 FM IF SYSTEM S3.25 Microcomputer magazine MOLE% PINS 10041,00 7404- .18 7490- .49 LM 3201 5. 24V pays well for 1000158.00 7405- .18 7491- .79 EG $1.50 microcomputer articles! Send standard 8 PIN MINIDIP SOCKETS 5.32 7406- .35 7492- .49 741V or 741C OP. AMP 3.31 7407- .33 709C OPER. AMP .. 5.25 10 7493- .49 self- addressed stamped envelope NOW WATT ZENERS 7408- .18 7495- .74 340T -5. 8, 12. 15, 18. 24V 3.9, 4.7. 12, 18. OR 22V EA. 5.75 7409- .18 7496- .79 POS REG 10 -220 51.75 for FREE AUTHOR'S KIT. 1 WATT ZENERS 7410- .15 loi OPER. AMP., HI PERFORM 3.75 4.7, 5.6. 10, 12. 15. 18. 22V 74107- .34 OR 5.25 EA. 7411- .25 74121- .38 747 -DUAL 741 5.65 Schneider Publications, 449 Elder Ln., 7412- .30 74123- .74 556 -DUAL TIMER 51.30 540 -70W POWER DRIVER S2.50 N.W., Rapids, Silicor Power Rectifiera 7413- .45 74125- .54 Cedar Iowa 52405. 7414 -1.45 74126- .54 LM 3900 -QUAD OP. AMP 5.49 PRV lA 12A 3A 50A 125A 7416- .33 74150- .92 LM 324 -GOAD 741. 51.50 100 .06 .14 .30 .80 7417- .33 74151- .69 560 -PHASE LOCK LOOP 52.00 200 .07 .20 .35 1,15 4.25 7420- .15 74153- .79 561 -PHASE LOCK LOOP S2.00 400 .09 .25 .50 1.40 6.50 7425- .27 74154 -1.05 565 -PHASE LOCK LOOP 52.00 600 .11 .30 .70 1.80 8.50 7426- .24 74155 -1.05 566 FUNCTION GEN 52.00 TUBES 567 -TONE DECODER $2.00 800 .15 .35 .90 2.30 10.50 7427- .27 74157- .75 .95 LM1310N STEREO DEMOO 52.75 1000 .20 .45 7430- .15 74161- 1.10 2.75 12.50 7432- .24 74163- .95 LM 370 -AGC SQUELCH AMP 5.70 7437- .29 74164 -1.10 555-2 us - 2 HR TIMER 5.53 RADIO & T V. Tubes --36 cents each. Send for free 7438- .29 74165 -1.10 553 GUAD TIMER 53.50 Catalog. Cornell, 4213 University, San Diego. Calif. 92105. CT700 CALENDAR ALARM 7440- .15 74173 -1.35 1458 DUAL OP AMP 5.65 CLOCK CHIP $7.50 7441- .95 74175- .95 LM 380-2W AUDIO AMP. 51.10 TUBES receiving, factory boxed. low prices. free price list. 74177- LM 377 -2W STERO AUDIO AMP $2.50 7442- .59 .75 N.Y. REGULATED MODULAR 7445- .79 74181 -2.30 LM 381- STEREO PREAMP. 51.50 Transleteronic. Inc., 1365 39th Street, Brooklyn, POWER SUPPLIES 7446- .87 74192 -1,10 LM 382 -DUAL AUDIO PREAMP $1.50 11218A, Telephone: 212 -633 -2800. LM 311 -HI PER. COMPARATOR - -15VDC AT 100ma 115VAC INPUT$24.95 7447- .87 74193 -1.10 5.95 7448- .85 74194 -1,15 LM 319 -Dual Hi Speed Comp 51.10 TUBES "Oldies ", latest. Lists free. Steinmetz. 7519 5VDC AT 1A, 115VAC INPUT $24.95 LM 339 -OUAD COMPARATOR 7472- .28 74195- .74 3.25 Maplewood, Hammond. Indiana 46324. 12V . 5A $24.95 7473- .34 74196- .95 8038C IC VOLT CONT. OSC. $3.90 75324 IN 4148 (IN914) 15/$1.00 7474- .35 -1.75 TRIACS SCR'S CASH PAID FOR OLD TUBES AND AMPLIFIERS. RCA45, 7475- .49 75491 -1.10 t 103 1024 bit RAM $2 75 RV 1A 10A 25A 1,5A 611 35A RCA50. WE300B, WE3508. MACINTOSH MC20. MC22. NEC 6003 2048 bit RAM $6.00 100 7. 1816, 303 1101 256 bit RAM $1.40 ALCO MINIATURE TOGGLE SWITCHES MC275. MARANTZ Contact M. Takabe, Room 8223 PROM $2.50 MTA 106 SPDT $1.50 Fifth Ave., NYC 10016. 7489 RAM $2.30 MTA 206 DPDT $2.25 600 70 2.3 3. MUSICAL INSTRUMENTS Term s: FOBCambridge, Mass. Send Check or Money Order. Include Postage. Minimum SOLID STATE SALES OFEOUR ORDERS THE TO 60% DISCOUNT. Name brand instruments catalog. Order $5.00. COD'S $20.00. 4 P,O. BOX 74A DAY WE RECEIVE THEM UP SOMERVILLE, MASS. 02143 TEL. (617) 547 -4005 Freeport Music, 455N Route 110, Melville, N.Y. 11746. WHOLESALE! Professional Guitars, PA Systems, Altec Speakers, 240W RMS Amplifiers. Free Catalog. Carvin. Escondido. Calif. 92028.

CIRCLE NO 52 ON FREE INFORMATION CARD 114 POPULAR ELECTRONICS

www.americanradiohistory.com Your C oite of 100' S OF BARRELS any kit vv ivaR' PURCHASED: I

I I Í Ï /\ / I For I Me flat time ' I erchandi.er 11 s Pol P Itrod11ca \\Y í \ % st , My/ ömtq °CpnOmital aY Raw c- - ____/V- T____I \ - le OaYS',T lihy Th back CliZ..i.u"..ivi

bar I ov :s Every carries money beck P 1 úgw EXCLUSIVE `BARREL' kit °. °aMK°es'/ `chins THE BIGGEST INFLATION -FIGHTING VALUE EVER. TEST 'EM YOURSELF 'N SAVE! RE- TEATEmstiM IT al Dß° t .. Me BARREL KIT :1 BARREL KIT :2 I KIT : a ..... I(IT 44 KIT A5 BARREL KIT :7 5N7400 DIP IC'S LINEAR OP AMPS, 1N414$/914 1 "4000" RECTIFIERS SCRS, TRIACS, VOLUME CONTROL NIT DIPS SWITCHING DIODES d 75 for $1.98 75 for 00 for $1.98 QUADRACS BONANZAI 4 p/. SUBMINIATURE CO 40 for t'a' IF TRANSFORME' Marked td and /or with 16 mitre are the famous micro Din mers r include gates, $1.98 100 forf $1.98 miniature certifier. 1i ñe 40 for $1.9 $1.98 Rip Mope, - May include 66ín. You sen new his 671155. 60 for $1.98 er.. 709-,, ¿)Ìd000 series. May lie, All the lampa. Raw eo - t W'SA GUARAN. e0des 6 tua, In- diodes. e s lchinS elude 26,560, a d, 200, b Yth. Raw factory Sivgie. duale, g ones pl Amazing. t. dao. inapte, style, big o, TEEN SATISFACTION!92092415 marked and un- diode. these Prices 400, 800- 800 and 1000 stock i All the 10 19D tYPee. one - a, wa known'. smell ones. From Cal N. 930Ú341S marked. Cat. No. 93002415 Cat No.Mo. 83093416/ miters. Cal. Ne. 9]093417 Cet No. 93C91419 930Ú3431r are radio man 11f5.11.°971. Mo. B3C 63433 KIT :10 BARREL KIT :1 1 KIT :12 BARREL KIT :i 3 KIT :14 BARREL KIT :IS BARREL KIT :1S ROMS- REGISTERS POWER TAB POWER TAB RESISTOR NETWORKS PRECISION RESISTORS MOSFET TRANSISTORS DISC CAPACITORS TRANSISTORS SO for TRANSISTORS ZOO for $1.98 40 for 40 for 40 for 200 for 1.98 $1.98 ,- $1798 $1.98 í í' $1.98 60 for $1.98 24 to 40 deli en, NPN' Marked end unmarked. Red Pin ^iv lactic T0220 type. PNP, plastic 0220 type All 4 leaders TO -18 case. values. marked, internal factory Assorted 2N y M o 1A unmarkeA t /s, cue [ype gnat. numbers, Assorted 2N numbers, By Corning Glans, i arked mcludu UHF transistor numbers, ate Ne. 920113 {3a a, 2 wet n. NO. f30Ú3136 too. No. Cal. No. 93093930 C.I. Ne. 920Ú343S Cet Ne. 93093{]6 Pin dip P &4. 2CÚ242) Cet 930Ú341f

KIT :17 KIT :19 BARREL KIT :19 BARREL KIT :20 BARREL KIT :23 BARREL KIT :24 KIT :25 LINEAR 7400 DIPS ZE ER-RECTIFIER IX DIPPED MOLARS LONG LEAD DISCS 'RTL" IC'S NIGH VOLTAGE METAL CAN RECTIFIERS TRANSISTORS for I0'='' 1$1 O 75 for 98or --100 for $1.98 98 60 for for Subminiature, Nñr6. $1798 1, and eludes Tincal r t ,torn made, Factory distributor k $1.98 Marked and unmarked, un- ct,fienelt's m xed et the Inrlutle. TO .'rt TO -I, TO- shiny finish!rimeBine recto- sale ". Prime. All i TO -fi ass brand Up to 12,000 volts. 4 nuls, nain. sal nu bers of raw tacs- factory, we Cannot seps- ry dumping 'em to barrels, marked only. Long leads. w. May include 908, 911, epoxy. axial leads. be r,.1, nm ked etc. ,ry Cork. Ne. 92092431 rote. Cet. Ne, 92CO2432 912, 913, a Cet Ne. 92CO2597 Cat. No. 1201125911 etc. 92CO2601 Cat. Ne. 92CÚ3603 Cat. No. 92C112801

BARREL KIT 42S BARREL KIT :27 BARREL KIT :29 BARREL KIT :29 BARREL KIT :30 BARREL KIT :31 KIT #32 PLASTIC PREFORMED DISCS CERAMIC CAPACITORS VITAMIN Q CAPS PREFORMED METALLIC ay{ TRANSISTORS TRANSISTORS RESISTORS RESISTORS WITH A HOLE IN IT 100 for o 200 for 100 for 100 for $1.98 51.98 a4 $1.98 4111111 200 for $1.98 100 for $1.98 50 for $1.98 t Cet. No. 92602610 $1.98 ill !'I mfrs shelf inventor/ Not only do the barrels Every type of oil- impreg- M'e gat barrels or and Made mostly by Corning, m n but he dumped bar- contain dugb,nea, but far- Bated cape, worth 82. Ka" welters for Dc he caca( made. Can't name factory bu[ we Type TO -92 ITO -IBI, all Is. Preformed, for PC use. dumped, Erie Centre- But the "oie barrel" sale l'ouilw gets Mostly 4.taerbasrelw ar 1 or t, bought barrels f 25 watt- variety of manufacturers. Mixed velues too' lab, molded type r too. gives you the bargain -of- 100: t/, 100n1e. a sclera. 695 Cpl. of e h tg. hole mid- 291 :'.s. Cat. Nw 93CO2804 Cet No. 920113605 Cat Ne. 92002606 a- lifetime. 93CÚ360) :al Ne. 920112605 .sises. Cat Na. 93C92609 Ale. PNPS and NPN'S.

BARREL KIT :34 KIT #75 BARREL KIT #36 BARREL KIT :37 NIT :39 KIT :39 KIT :0 TUBE SOCKETS - ,v --NEON LAMPS GERMANIUM DIODES 1 AMP "BULLET)" 2 AMP RECTIFIERS 2N3055 HOBBY PNP HIGH -POWER RECTIFIERS TRANSISTORS TRANSISTORS 1 300 for yk 200 40 for for 75 for + % 20 $1.98 G, 100 for 15 for Yyy for ' Gnon le tube $1.98 $1.98 sockets. Famous maker, Dulac $1.98/ $1.98 .till it demand, Barrel. Famous NE -2'e. All Ilions $1.98 $159 Pupal ar gar manuumi TO -3 But 1,d barrels: d'a, Never grow. e a 'le, as d, y its -CYLINDER" yM. tbc°° From !.clots t o youo thous 5'a, 7, S. but lactlry made millions this 'e the way he RE- case unite ow eva,lable ages` silicon, axi figes to Mallory, includes all volt- 1 he famou- of ttPea and barreled 'em, Your ad- the d °1e barrel" prices. all of .920112 ages up 1 192 Axial . have Cet No. 92CÚ2612 vantage. types t pot.. Ubar- 92C92513 'actor,. 97012614om/ Cat Me. 92093616 lends. Cot. No. 93093616 vela. Ne. 92CÚ3617 Cet.Cat. Ne. 209361 Cat.

BARREL KIT :41 BARREL NIT :2 BARREL KIT #11 KIT BARREL NIT BARREL KIT 015 KIT OS1 TO SCRS 100 ITT "GLASS 4000 G.E. 3.5 WATT . 741 MINI DIP: QUADS! QUAD OPTO -S : SIGNAL SILICON AMPLIFIERS i "BONANZA" 30 for RECTIFIERS #'GM 5O for DIODES COUPLERS $1.98 25 for oY ! ' S0 foOr l. 200 for $1.98 30 for $1.98 $1.98 $3798 LM we bot 1.000'7 awn IMAGINE! These Dopul. Just in! 1914000 ail.. $I'9á $1.90 ' 1 men mu time. the er Imizike d irrp oD amDe u cue ov ' TO -31, r 7än757 in oat' vow i 1 m r e ay Dc axial yeea.. r both. n,. HobbyY tYOe, factor` fall- Barrels 'n barrel 01 iv one erre Why the ter good, made D kir. Slues sri 6571 market. types.t pee, all axial leads. We don't ate we d hem in Ho is buyer's parcelled 6917 WE DON'T Values o 800 volt, 19 Cree 59 ,° I200v too! test factory may be zone rr, Ce 6 2p- barrels. These n How manu can we get don't know, know. types. run.pop. Cat. Na 930Ú36I8 Cal. No. 93002630 knows. 92092624 ed. Ce/. Ne, f2CY3636 93CÚ161) Cet. Ne. 93CÚ2836 tarions Cet No. f3CY3639

cR^IT :6f BARREL KIT :53 BARREL KIT #5 KIT #55 KIT #5 BARREL KIT :57 BARREL KIT :5 3 POWERS) -POWER SLIDE SWITCHES o O'er+^ JUMBO RESISTOR PAR DIGIT READOUTS DIGIT READOUTS POWERS) NI RECTIFIERS 87 vP S'7 100 -pc. $1.98 30 for 15 for 100 for 30 for _> 500 for $1.98 alp. 9261,272/ $1.98 t $1.98 $1.98 $1 98 $1.98 39113930 Assortm metal filma,-- preci- All sizes. dpdt The bargain of M.rim.l carbons. metal oxide Bargain of a lifetime! All National cleaned i ware. Large distributor leaned 511- Amn studs: 2d, omeanasrie. Tremens Fire rima 7s offered by walla. from t/s watt t1 x got was 1 barrel he borne w we have house, Barrels of Power ír material. Pas- doua n np roieflr 100'7 of Pals Peke for lha coomy- Color coded & pICol types. Multi- of NSN -33 type 3 11 x .I 2C "Ilse" rejects, switching 09272 minded bargain bun marked. Worth $10. plexed. ó7tCat Mo. 93CÚ3)21 readouts.rendnuta. ó7t No. 920Ú2T33 Cat No. f3CU2)24etr Cat. No. 93092735 Gt. No. 93CY3714

BARREL BARREL KIT -S9 BARREL KIT :52 BARREL KIT :0 BARREL KIT :1 KIT :54 BARREL KIT :es . BARREL KIT :57 POWER TRANSISTORS MIXED IC'S DTL'S IC'S POLYSTYRENE CAP 6 -DIGIT ARRAYS MIXED READO TS. '. 2 -WATT AMPLIFIERS 40 for ,c,..44...., 100 for 75 for 30 for / -,y; 50 for $1.98 100 for L,y _ r( $1798 $1.98 $1.98 24/for $1.98 $1.98 ®'4"/ $1.98 S w Bendix B -51100 All shapes: 7.0 v . This is Prime barrel te- Facto, urn such Buy from the barrel 'n save' a , l l 9000, ROM4, Here's bargain! This i a - e e s tt..sto Man. ll 1100 RTL.. 'al, Who want DTL'.? Finest cap, made. Asa gam- numbers as IMAN -Cs. MAN- LM -380 types in dip asks. sod, purchased from DTI.'.., lineern . f ll kind a, 930, 936, 9d6'e, rYour( in bee bought 10 barrels Nat sal "dumph lane- 7's, MAN -.4's, 11 barrels 5 Are they good? We don eater. have millions of What a mix! Have fun r loan. They're marked values; lion le stopped here! - from factory, mixed to re You ant m end out We gut - emt, Cat. Ne. 92093727 Cat. Ne. 92002730 too. Cat. No. 92003735 all good.Cat. No. 9301)3)39 Cat No. 920112732 test - OK? 92002)33 Tillions, cat. No. 91CV2734

:SS BARREL KIT #70 RREL IT :71 BARREL KIT :72 BARREL KIT :7 1 WATTERS / GIANT 'LION) PIPE.- 'DOUBLE BARREL TWIN PA KS :4 obody se met 'em! MYm0P Its "bugs" s why the far- 20 for e Polished, all perfect. Mak- barrels of lare, pot Y'e, dump barrels. 14)O S° m ye suppliers don't ere Maker of these dumpede in i in for $1.98 count, but throw 'ern n the overstock. 10 -ft long, me molded., pleat., barrels. You get 2, 4, We .don't wish to separate $1.98 I S0 1LOUT d00 -M W. 800 glue fibers in bundle, ramies, discs, etc. Nifty wide volMgee 5 values 10 barre. It's WI gold mine. r g stripe A receptacles. What east Man -3'a. /7' 60 1 -watt All marked, 931:112735 jacket Cal- No. 92G112737 shop eupplr. 92012736 buy! Cet. Ne. 93002739 up to 300 inf. 92.112)4) 10 Man -x / q q IO 12 to 15Y. Cat, Ne. 92C112636 Cat. Ne. 920112929 BARREL KIT :75 KIT gas KIT :77 BARREL KIT :7 BARREL KIT :79 TWIN PAN 40OMW ZENERS "BROWN" BODY "RED" BODY DARLINGTON :9 I TWIN PAK :10 1WATT ZENERS POWER RESISTORS 100 for 100 for /My TRANSISTORS TRANSISTORS POWER TABS READOUTS $1.98 $1,98 40 for $1.9 25 for 10 6 -digit 15 0 74 for -WIND- 40 for $1.98 5 9 -digit " '' S1.98 _ ir 1 Factory out of m.! Amazing Fanon as 410 -mwe. il, D-10 series hua $1.98 $1.98- "' offer: 6, 8, 10, 12 to 15V. Never-to-me-again offer, 6, v'ollage, Darlington., hi. 1.42 series. You te t -go Hrown body, power rah Hobby ypes, from calcula. 40 Oxide 2- wattera. 5'outewo g, into you ow biz! High 10, 12, 15V. under current. non's. Factory lie Dart ingtona a - d, raw for maker'' Oxide x- wetter.. glass pak, Double glua. Double plug, discontinued, Power tabs, current. hi -V. NPN. Pl.. factory stock Why pain Cat. Ne, 93092934 Cat Ne. 920921135 Cat Ne. 92002740 Cat. No. 920112741 Cet. Ne. 92091741 fgt. No. 93002743 more' Cat. No. 930113744

Tortue: add s:,atake Rated: net :10 BARREL KIT BARREL BARREL KIT :50 //////------#1 KIT :52 KIT '13 KIT #4 Phone Orders: Wakefield, Mass. HOBBY CAP SUBMINI RESISTORS 9000 SERIES ICS 15 for $1.9 Retail: 16-18 Del Carmine St Wakefield, M a. for (off Water Rtreet) C.O.D.'S MAY BE PHONED 200 for , 100 for SO for LM -3oT $I,9ó MAN- VOLTA OE 10c CATALOG on Fiber Optics, 'ICs', Semi's. Parts $1.98 $I.9á $1 98 R[OULATO RS nlE c'LAW" r,v l n mile, ',duct mn hoe stopped. By Leo hobby or experimental National, From factory re ec ed them or MINIMUM ORDER 54.00 Dowels 1 oils, tu- Pc, uóright type./r Color od- calory ',um,. e you. Assortment of POW' um. for understanding the tua length , hulas, but unmarked with ed. watt. A.at values. Mar aeries factory fallouts, of lead May Include working of "m " or .1.- a all kinds of sizes. All good: Came. to us In a barrel. overruns. Who knows! 6, 6, 8, 12, 15, 18.24 volt. lelnr readou. n,A segment you Irsl. Cet. Ne. 92CÚ3)45 Gt. Ne. 910Ú27M GetrNa 2003534 Power tab, 93093636 may be mis ai ng 93CÚ36)9 POLY PAKS P.O. BOX 41 E. LYNNFIELD.MASS. 01540

CIRCLE NO. 44 ON FREE INFORMATION CARD JANUARY 1976 115

www.americanradiohistory.com HEAVY DUTY POWER SUPPLY ELECTRICAL SUPPLIES & EQUIPMENT This power supply is surplus from a maker of computer peripherals. It has outputs of +5v ` @ 5 amps, -5v @ 500ma, +12v @ 2.5 amps, PLATING Equipment, Portable Platers. Supplies and and -12v @ 200ma. All voltages are well "Know- How." Build your own tanks for nickel. chrome. etc. Easy -to- install PVC liners. filtered and regulated. Ideal for your micro - Rectifier components -all or minicomputer. All are tested & working. For sizes. Schematics. parts lists, formulas. operating instructions for all plating. Guaranteed to save you %- 101/2" x 131/2" x 7" high, shipping weight 22 lbs. 25 75 %. Some good used units for sale. Write for details. STOCK NO. P5312 $34.95 Platers Service Company, 1511 -PE Esperanza. Los faster Angeles, Calif. 90023. ALCO KNOBS FOR EVERY APPLICATION . Machined aluminum knobs with 2 setscrews. Clear anodized Ill TAPE AND RECORDERS finish. Latest distributor price $1 .65 to 1.05 each. ALCO NO O.D. x HT. DELTA NO. PRICE ". service KS 500A .500" x .625" w /skirt P6176 .40 ea, 10/3.50 RENT 4 -Track open reel tapes -all major labels -3.000 K 700A .750" x .620" P6177 .40 ea, 10/3.50 different - free brochure. Stereo -Parti. 55 St. James Drive, K 1250A 1.250" x .750" P6178 .50 ea, 10/4.50 Santa Rosa, Ca. 95401. 1930 -1962 Radio Programs. Reels. $1.00 Hour! Cassettes, COMPLETE STEREO AMPLIFIER CHASSIS 51.00 Show! Mammoth Catalog. $1.25. AM Treasures. USE Box 192PE. Babylon. N.Y. 11702. This complete stereo amplifier has 2 push RECORDS -TAPES! Discounts to 73 %. all labels; no pur- button selected inputs, with indicator lights, chase obligations: newsletter; discount dividend certificates; Free and one has adjustable sensitivity. It has 100% guarantees. details. Discount Music Club. 650 Main St.. Dept 5 -16. New Rochelle. New York. ' a '..z j;- transformer power supply, 15 watts per ZIP N.Y 10801. -' °, channel, and seperate Volume, Bass, 9 CLASSICAL CASSETTES! FREE CATALOG. Better quality. 4 : Treble, & Belance controls with knobs. 50% less cost than records! CCC. Box 506PE. Saddle > ' Rugged steel chassis 11" wide, 81/2" deep, River. N J. 07458. 3%" high. Just needs 115v AC and speakers. Shipping weight 7 lbs. CODE STOCK NO. P5286 Complete stereo amplifier $19.95 PERSONALS

MINIMUM ORDER $5.00. Include sufficient postage, excess refunded. Send for new 88 page Catalog 15, bigger than ever. MAKE FRIENDS WORLDWIDE through international on correspondence. Illustrated brochure free. Hermes. Berlin BANKAMERICARD and MASTERCHARGE lt. Box 110660/ZD. Germany. -a! now accepted; minimum charge $15.00. Please m® PH.D's. MASTER's. BACHELOR's official nonresident A - m?*! include all numbers. Phone orders accepted. College Degrees easily acquired through mailorder Uni- versities. Revealing Directory - $2. Counseling Connec- Enclose sufficient postage. Excess will be refunded. Send all tion. 5495 Claremont. No BSG. Oakland.CA 94618. for our new catalog 14. 64 pages of electronic bargains. MOVIE FILMS DELTA ELECTRONICS CO. mail A 8MM -SUPER 8 -16MM MOVIES! Biggest Selection! Lowest Phone (617) 388 -4705 Prices! Free Catalog! Cinema Eight. Box PE. Chester. 06412. CIRCLE NO 15 ON FREE INFORMATION CARO Connecticut

CB SPECIALS -R.F.DRIVERS -R.F. POWER OUTPUTS -FETS 2SC481 1.85 2SC767 15.75 2SC866 5.85 2SC1449-1 1.60 40081 1.50 OEM SPECIALS 2SC482 2SC013 .85 1.50 25C475 1.50 40082 3.00 1N270 10 2N960 .55 2N2219A .30 2N2913 75 1.00 2N4401 20 2SC495 1.10 2$C774 2SC1014 2N3740 1.75 1.50 25C1678 5.50 2SC608 7.90 1N914 .10 2N962 .40 282221 .25 2N2914 1.20 2N3771 1.75 2N4402 .20 2SC502 3.75 2$C775 2.75 2SC1017 1.50 25C1679 4.75 SK3046 2.15 2N967 .50 2N2221A 2SC517 4.75 2SC776 .30 2N2916A 3.65 2N3732 1.90 2N4403 .20 3.00 2SC1018 1.50 2SC1728 2.15 SK3047 3.75 2N173 1.75 2N1136 1.35 282222 .25 2N3019 .50 2SC614 3.80 2SC777 4.75 2SC1173 2N3773 3.00 2N4409 1.25 25C1760 2.15 SJ2095 3.50 2N178 .90 2N1142 2.25 2N2222A .30 2N3053 .30 2N3819 .32 2N4410 .255 2SC615 3.90 2SC778 3.25 2SC1226A 1.25 25C1816 5.50 SK3048 3.25 2N327A 1.15 2N1302 .25 2N2270 .40 2SC616 4.15 2SC797 2.50 2SC1237 2N3054 .70 2N3823 .70 2N4416 .75 4.50 2SC1908 .70 SK3054 1.25 2N334 1.20 2N1305 .30 2N2322 1.00 2N3055 .75 2N3856 .20 2N4441 .85 2SC617 4.25 2SC798 3.10 2SC1239 3.50 25C1957 1.50 2N336 .90 2N1377 2SC699 4.75 2SC781 .75 2N2323 1.00 2N3227 1.00 2N3866 .85 2N4442 .90 3.00 25C1243 1.50 2SF8 3.00 25K19 1.75 2N338A 1.05 2N1420 .20 1.35 2N3247 3.40 2SC710 .70 2$C789 1.00 2SC1306 282324 2N3903 .20 2N4443 1.20 4.75 HEP-53001 3.25 2SK30 1.00 2N398B .90 2N1483 .95 2N2325 2.00 .N3250 .50 2N3904 .20 2N4852 .55 2SC711 .70 2SC796 3.15 2SC1306-1 4.90 25D235 1.00 2SK33 1.20 2N404 .30 2N3375 6.50 2$C735 .70 2SC799 2N1540 .90 2N2326 2.85 2N3905 .20 2N5061 4.25 25C1307 5.75 MRF8004 3.00 2N443 1.75 2N1543 2.70 2N2327 3.80 2N3393 .20 2N3906 .25 2N5064 .50 2SC756 3.00 2SC802 3.75 2SC1307-1 6.00 4004 3.00 3SK40 2.75 2N456 1.10 2N1544 .80 282328 4.20 2N3394 .17 2N3925 3.75 2N5130 .20 2$C765 9.50 2SC803 4.00 2SC1377 5.50 4005 3.00 3SK45 2.75 2N501A 3.00 2N1549 1.25 2N3414 .17 .15 10.15 2N23.9 4.75 2N3954 3.50 2N5133 2SC766 2SC839 85 2SC1449 1.30 40080 1.25 3SK49 275 2N508A .45 2N1551 2.50 2N2368 .25 2N3415 .18 2N3954A 3.75 2N5138 .15 2N555 .45 2N1552 3.25 2N2369 .25 2N3416 .19 2N3955 2.45 2N5198 3.75 2N652A .85 2N1554 1.25 282484 .32 2N3417 .20 2N3957 1.25 2N5294 .50 JAPANESE TRANSISTORS 2N677C 6.00 28557 .15 282712 .18 2N3442 1.85 2N3958 1.20 285296 .50 2SA52 .60 258187 .60 2SC458 .70 2SC815 .75 2SC1569 1.25 .25 281560 2.80 2N2894 .40 2N3553 1.50 284037 .60 2N5306 .20 2SA316 .75 2S8235 1.75 2SC460 .70 2SC828 .75 2SC1756 1.25 2N706B .40 281605 .35 2N2903 3.30 2N3563 .20 2N4093 .85 2N5354 .20 2SA473 .75 258303 .65 25C47ß .80 2SC829 .75 2N711 .50 2N1613 .30 2N2904 .25 2N3565 .20 2N4124 .20 2N5369 .20 2SA483 1.95 2SB324 1.00 2SC491 2.50 2$C830 1.60 25030 .95 287118 .60 281711 .30 2N2904A .30 283638 .20 284126 .20 2N5400 .40 2SA489 .80 258337 2.10 2SC497 1.60 2SC839 .85 25D45 2.00 2N718 .25 2N1907 4.10 2N2905 .25 283642 .20 2N4141 .20 2N5401 2SA490 .70 2513367 1.60 2SC515 .80 2SC945 .65 25D65 .75 2N718A .30 2N2060 1.85 2N2905A .30 2N3643 .15 2N4142 .20 2N5457 .35 2SA505 .70 258370 .65 2SC535 .75 2SC1010 .80 2SD68 .90 2N720A .50 2N2102 .40 282906 .25 2N3645 .15 2N4143 .20 C103Y .25 2SA564 .50 258405 .85 2SC536 .65 2SC1012 .80 2SD72 1.00 2N918 .35 2N2218 .25 2N2906A .30 2N3646 .14 2N4220A .45 C103D .40 2SA628 .65 258407 1.65 2SC537 .70 2SC1051 2.50 2SD88 1.50 2N930 .25 2N2218A .30 2N2907 .25 2N3730 1.50 2N4234 .95 C106B1 .50 2SA643 .85 258415 .85 2SC563 2.50 2SC1061 1.65 250151 2.25 2N956 .30 2N2219 .25 2N2907A .30 2N3731 2.75 2N4400 .20 C106D1 .75 2SA647 2.75 258461 1.25 2SC605 1.00 2SC1079 3.75 250170 2.00 2SA673 .85 .SB463 1.65 2SC620 .80 25C1096 1.20 25D180 2.75 SILICON UNIJUNCTIONS INTEGRATED CIRC. RECTIFIERS 2SA679 3.75 258471 1.75 2SC627 1.75 25C1098 1.15 2SD201 1.95 2SA682 .85 2SB474 1.50 2$C642 3.50 25C1115 2.75 25D218 4.75 10 100 2SA699 1.30 2S B476 1.25 2$C643 3.75 25C1166 .70 25D300 2.50 2N2646 50 282160 .65 UA703C .40 2SA699A 1.75 258481 2.10 2SC644 .70 2SC1170 4.00 25D313 1.10 2N2647 2N4870 .50 709C OP. AMP. .25 IN4001 .60 5.00 2SA705 .55 256492 1.25 2SC681 2.50 2SC1172B 4.25 25D315 .75 2N6027 60 2N4871 741C OP. AMP. .25 N4002 .70 6.00 2SA815 .85 2SB495 .95 2$C684 2.10 2SC1209 .55 250318 .95 2N6028 70 2N4891 .50 7400 .15 N4003 .80 7.00 2SA816 .85 258507 .90 2$C687 2.50 2SC1213 .75 25D341 .95 D5E37 25 2N4892 .50 7404N .18 N4004 .90 8.00 258511 .70 2$C696 2.35 25C1226 1.25 25D350 3.25 2N4893 .50 7430N .19 N4005 1.00 9.00 25822 .65 2SC712 .70 2SC1243 1.50 250352 .80 2N4894 .50 74100J .35 N4006 1.10 10.00 2SB54 .70 2$C206 1.00 2SC713 .70 25C1293 .85 25D380 5.70 MU10 40 74H55N 35 84007 1.20 11.00 25856 .70 2SC240 1.10 2SC732 .70 2SC1308 4.75 2SD389 .90 2SB77 .70 2SC261 .65 2$C733 .70 2SC1347 .80 25D-390 .75 258128 2.25 2SC291 .65 2SC739 .70 2SC1383 .75 2SD437 5.50 New -Tone Electronics 258135 .95 2SC320 2.00 2SC756 2.00 2SC1409 1.25 258152 4.50 2SC352 .75 2SC762 1.90 2SC1410 1.25 C10681 .50 P.O. Box 1738 A 258173 .55 2SC353 .75 2SC783 1.00 2SC1447 1.25 258175 .55 2SC371 .70 25C784 .70 2SC1448 1.25 Bloomfield, N.J. 07003 258178 1.00 2SC372 .70 2SC785 1.00 2SC1507 1.25 258186 .60 2SC394 .70 2SC793 2.50 2SC1509 1.25 Phone: (201) 762 -9020 POWER- TRANSISTORS HIGH -VOLT. TV. TYPE ALL PARTSr* GUARANTEED AND TESTED ON PREMISES.

BU204 1300V 3.90 BU207 1300V 5.40 2SC1172B 1100V 4.25 N J. residents add 5% sales tax. Minimum order $5.00. All orders BU205 1500V 4.70 BU208 1500V 6.25 2SC308 1100V 4.95 add $1.00 postage. Dealers write or phone for discount prices. BU206 1700V 5.90 2SC1170 1100V 4.00 2SC1325 1100V 4.95 116 CIRCLE NO. 31 ON FREE INFORMATION CARD POPULAR ELECTRONICS

www.americanradiohistory.com DATA SHEETS WITH EVERY ITEM 749 IC WITH EVERY $10 ORDER* hiu, POTTER FREE INVENTIONS WANTED BRUMFIELD REDUCE YOUR PROJECT COSTS kgiM Type KHP Relay MONEY -BACK GUARANTEE .11 PDT INVENTORS: Protect your ideas! Free "Recommended 24 -HOUR SHIPMENT :t Procedure- Washington Inventors Service, 422T ' 24 VDC (650 coil) $1. 50 EA. ALL TESTED AND GUARANTEED Washington Building. Washington. D C 20005. 120 VAC (10.5 MA coil) $1.75 EA. TRANSISTORS DIP TRIMMER 2N3563 TYPE RF Amp & Osc to 1 GHz (p1.2N918) 6/51.00 DIp 50CIIET5 253565 TYPE Gen. Purpose High Gain IT 0-92/1061 6 /51.00 8 PIN PCB s 22 -12 turn trimpots Inventors Wanted 2N3567 TYPE High- Current Amplifier /Sw 500 mA 4/$1.00 which plug into 14 PIN PCB 26 2N3866 TYPE RF Power Amp 1.5 W @ 450 MHz $1.50 PIN a DIP socket RECOGNITION, FINANCIAL REWARD, 16 PCB .30 e Send for FREE 253903 TYPE GP Amp & Sw to 100 mA and 30 MHz 6/$1.00 -5K and 200K 24 PIN PCB 75 , OR CREDIT for "inventing it first" 2N3919 TYPE RF Power Amp 10 -25 W@ 3 -30 MHz $3.00 x " x INVENTORS KIT 40 PIN PCB 1.25 -V" " Includes 254274 TYPE Ultra -High Speed Switch 12 ns 4/$1.00 -4 lead" spa" may be yours) We'll develop your Vital Into, PIN WIRE WRAP MPS6515 TYPE High-Gain Amplifier hFE 250 3/$1.00 14 35 3" .2" matron on Protection, idea, introduce it to industry, Dsrslopmsnt, MsrkNng Assort. NPN GP TYPES, e.g. 2N3694, 2N3903, etc. I15) $2.00 Each $.65 10 for $4.95 of your Invention 2N3638 TYPE (PNP) GP Amp & Sw to 300 mA 4/$1.00 NPN TO3 POWER publicize it, negotiate fig Cash Important 2N4249 TYPE (PNP) Low -Noise Amp 14A to 50mA 4/$1.00 TRANSISTORS "Invention I NATIONAL MOS TO-5 Sale or Royalty Licensing. Record Form" FET's: N- CHANNEL ILOW -NOISE) mm--'' Power transistor: Directory of SOO Cor- Dynamic shift registers TO -5 RAYMOND LEE ORGANIZATION porations Stroking 2N4091 TYPE RF Amp & Switch (T0- 18/1061 3/$1.00 PD -115W; VCE -60V; MM502 dual 50 Bit..$ .75 230 Park Ave. No New York, NY 10017 New Products 2N4416 TYPE RF Amplifier to 450 MHz 110-721 2/$1.00 HFE -50; FT -30K; MM506 dual 100 Bit.. 1.75 IPlease rush FREE INVENTORS KIT A -739 2N5163 TYPE Gen. Purpose Amp & Sw (TO -1061 3/$1.00 Case TO -3 MM5006 dual 100 Bit.. 1.50 2N5486 TYPE RF Amp to 450 MHz (plastic 2544161 2/51.00 Each 10 for $ .90 $6.95 MM5013 1024 Bit.. 2.25 E100 TYPE Low -Cost Audio Amplifier 4/51.00 MM5016 512 Bit.. 1.00 I Name ITE4868 TYPE Ultra -Low Noise Audio Amp 2/$1.00 410 (RCA) 200V; 10A, Static shift registers TIS74 TYPE High -Speed Switch 4011 3/51.00 Each $1.75 10 for $15.00 Address Assort. RF & GP FET's, e.g. 255163, MPF102, etc. I8) $2.00 MM504 dual 16 Bit. -$1.50 P- CHANNEL: MM505 dual 32 Bit.. 1.75 City State Zip 254360 TYPE Gen. Purpose Amp & Sw -106) 3/51.00 MM550 dual differential 170 Memories E175 TYPE High -speed 12517 3/51.00 BRAND NEW -- analog switch 2.50 J Switch ITO-1061 93410 - 256 X 4 RAM FREE "Tips on Marketing Your Invention." 1702 - 2048 BIT PROM PAMPHLET: JANUARY SPECIALS: 154154 0100E 30 V /10mA -1N914 except 30 V 25/$1.00 {256 WORD X 1 BIT} 2K STATIC UNITS, ULTRA - Write: United States Inventors Service Company, Dept. T. FULLY DECODED: HIGH VIOLET LIGHT ERASABLE. 1435 G Street NW, Washington. D.C. 20005. 252222 NPN TRANSISTOR GP Amp & Switch 5/$1.00 SPEED 440 NS}: OPEN $9.95 EACH 2N2907 PNP TRANSISTOR GP Amp & Switch 5/51.00 COLLECTOR OUTPUT: 16 253553 RF Power Amp 5W @ 150 MHz, 10 W P50 MHz $2.00 825129 - 1024 BIT ROM PIN DIP WITH DATA. 253904 NPN TRANSISTOR GP Amp & Switch 5/51.00 {256X4 PROM}: 50 NS: POWER DIS- INSTRUCTION FROM FAIRCHILD 2N3906 PNP TRANSISTOR GP Amp & Switch 5/$1.00 SIPATION .5 WHIT; TRI -STATE 2N5100 RF Power Amp 2 W@ 450, 1W @ 1 GHz $2.50 ONLY 92.25 10/118.95 $5.00 OUTPUT. EA. 8 - $34.95 E101 N- CHANNEL FET Low Current, Low Vp Amp /Sw 3/51.00 LEARN ELECTRONIC ORGAN SERVICING at home all MPF102 N- CHANNEL FET RF Amp -200 MHz 3/51.00 2102-2 MOS 1024 BIT MEMORY (DIP) makes including transistor. Experimental kit- trouble- 340 T IA VOLT. REG.-Specify 5, 6, 12, 15 or 24 V-W /Ckts $1.75 FULLY DECODED STATIC RANDOM ACCESS MEMORY I} shooting. Accredited NHSC, Free Booklet. NILES BRYANT 556 DUAL 555 TIMER 1 psec to 1 hour (DIP) $1.00 DIRECTLY TTL COMPATIBLE INPUTS AND OUTPUT e SCHOOL. 3631 Stockton, Dept. A. Sacramento. Calif 8038 WAVE FORM GENERATOR A, fl AWave W /Ckts $4.50 SINGLE SV SUPPLY - - NO CLOCKS OR REFRESH 95820. MM5316 DIGITAL CLOCK- Snooze /Alarm/Timer )) Hrs, Mins, Secs, 4 or 6 Digit -With Specs/Schematics $5.50 LEARN WHILE ASLEEP, Hypnotize! Strange catalog free $3.00 EACH 10FOR $27.95 LINEAR IC's: Auto -suggestion. Box 24 -ZD. Olympia. Washington 98501. 308 Micro -Power Op Amp (T13-5/MINI-DIP) $1.00

DEGREE IN ELECTRONICS through correspondence. Free 309 K Voltage Regulator 5 V@ 1 A (TO -31 $1.50 'gDIODE ARRAY catalog. Grantham. 2000 Stoner Avenue, Los Angeles. 324 Quad 741 Op Amp, Compensated IDIP) $1.75 r 11i(v 380 2 -5 Watt Audio 34 dB $1.29 10 - 1N914 Silicon Signal Diodes in one California 90025. Amplifier (DIP) 555 Timer 1 ps1 hr. NE555, LM555, etc. IMINI.DIP) $ .65 package. 20 leads spaced .1 "; no common INTENSIVE 5 week course for Broadcast Engineers. F.C.C. 709 Popular Op Amp I0IP /T0 -5) $ .29 connections. Each $ .25 10 for $2.25 First Class license. Radio Engineering Incorporated. 61 N. 723 Voltage Regulator 3-30 V @ t -250mA (DIP/T0-51 $ .58 SPECIAL Pineapple Ave.. Sarasota. Florida 33577 and 2402 Tide- 739 Dual Low -Noise Audio Preamp /Op Amp IDIPI $1.00 Numeric Display water Trail, Fredericksburg. VA 22401. 1458 Dual 741 Op Amp (MINI -DIP) $ .65 8223 741 Freq. Comp. OP AMP (01P/TO-5/MINI-DIP) 3/$1.00 y4" Single Digit PROM DIODES: GaAsP LED I,I ZENERS- Specify Voltage 3.3, 3.9, 4.3, 5.1, 6.8, 8.2 400mW 4/$1.00 9.1. 10, 12, 15, 18, 22. 24, 27 or 33V 1!10 %) 1 Watt 3/$1.00 WITH RH DECIMAL CORION CATHODE rr 153600 TYPE Hi -Speed Sw 75 V /200 mA 6 /51.00 PASS FCC E RAMS! M.mon:.. study - "Ton 1N3893 TYPE RECTIFIER Stud Mount 400 V /12 A 2/$1.00 SUPER SPECIAL $.59 326 WORD Amnion" toi FCC le end 2,C cis R.dio MEMORY 1N914 or 1N4148 TYPE Gen. Purp. 100V /10mA 15/$1.00 ACTUAL SIZE Telephone icon Newf., revrewd mWte1w TEN for $4.95 05 MHz, 7 -70 $5.00 *3.00 chaos quenrom M ath ',,, cower Si are. VARACTOR 5-50 W Output@ 30-250 pF Compact - 10 In 3" panel EA I digits width WOW in FCC ...me plus "S.II.Study AbHity F7 VARACTOR 1 -3 W Output @ 100.500 MHz, 5-30 pF $1.00 Highly legible - bright red character easily read 10 - 29 k" T..." SAN postpaid. Moreybsb Guo.nw `MAIL NOW! FREE DATA SHEETS supplied with every item from this within 10 feet over a wide viewing angle IMO.) WE PROGRAM value) Low power - 125 mW per digit at typical brightness ad. FREE ON REQUEST -749 Dual Op Amp 101.00 with every COMMAND PRODUCTIONS P.O. BOX 26348 -P FOR es EACH idei u1 S10 or more, postmarked prior to 1/30/76 Rlo,o lapnuuc MGM. FRANCISCO, 94126 SAN CALIF. ORDER TODAY-All items subject to prior sale and prices subject to RECTIFIER 1N4007 - 1 AMP - 1000 volt PRV change without notice. All items are new surplus parts - 100ä, func- tionally tested. SPECIAL! $ .13 each 10 for $1.00 SCORE high on F.C.C. Exams Over 300 questions and answers. Covers 3rd. 2nd. 1st and even Radar. Third and WRITE FOR FREE CATALOG offering hundreds of semiconductors not All IC's are new and tested. listed here. Send 100 stamp. fully SEND FOR Second Test. $14.50; First Class Test, $15.00. All tests. Leads are plated with gold or solder. TERMS: All orders must be prepaid. We pay postage. $1.00 handling Due to increased costs, orders under $26.50. R.E.I., Inc.. Box 806. Sarasota, Fla. 33577. charge on orders under $10. Calif. residents add 6% sales tax. Foreign FREE FLYER orders - add postage. COD orders - add $1.00 service charge. $7.00 add $1.00 postage and handling. UNIVERSITY DEGREES BY MAIL! Bachelors. Masters. Residents of California add sales tax. TWX: 910- 367 -3521 Ph.D's. Free revealing details. Counseling. Box 1162 -PEI. minimum on C.O.D. ' s. $10 Phone (916) 334 -2161 Tustin. California 92680. Mail BRB T LO11 P.O. Box e41778 SELF -STUDY CB RADIO REPAIR COURSE. THERE'S ELECTRONICS Sacramerto, CA MONEY TO BE MADE REPAIRING CB RADIOS. This easy - ELECTRD TICS 95841 to -learn course can prepare you for a career in electronics BOX 4181 BE, WOODSIDE, CA 94062 enabling you to earn as much as $16.00 an hour in your Tel. (415) 851 -0455 CIRCLE NO 10 ON FREE INFORMATION CARD spare time. For more information write: CB RADIO REPAIR CIRCLE NO 2 ON FREE INFORMATION CORD COURSE, Dept. PE016. 531 N. Ann Arbor. Oklahoma City. Okla. 73127. LEARN to BUILD AND TEST ELECTRONIC CIRCUITS FOR FREE Educational Electronics Catalog. Home study FUN AND PROFIT. Complete Details Free. Chapel Com- GOVERNMENT SURPLUS courses. Write to: Edukits Workshop, Department 713D, pany. 1154 West 27th Street, Erie, Pennsylvania 16508. Hewlett, N.Y. 11557. LEARN Digital Troubleshooting. Clocks. Test Instruments. UNLOCK your Future. Become professional Locksmith by etc. Details Free. Educational Technologies, Box 224. GOVERNMENT Surplus. How and Where to Buy in Your spare time homestudy. $13 in an hour possible. All tools, Reynoldsburg, Ohio 43068. Area. Send $2.00. Surplus 30177 -PE Headquarters Bldg.. equipment included. Facts FREE. Send name. Lock - Pass FCC Washington. D.C. 20014. GET INTO BROADCASTING: examinations, get smithing Institute (homestudy). Dept. 1373-016. Little Falls, lobs, start own station. Free literature. Broadcasting. Box MANUALS for Govt Surplus radios, test sets scopes. List N.J. 07424. 5516AA, Walnut Creek, CA 94596. 50 cents (coin). Books. 7218 Roanne Drive. Washington. TELEVISION repair course. Learn how to service tele- D.C. 20021. visions from master technicians. Send $6.00 for first lesson SURPLUS ELECTRONIC EQUIPMENT. government and and details to: Guardian, 20 E. Main. Ramsey. N.J. REAL ESTATE manufacturers' Grab Box Assortment- diverse. useful new AMATEUR Radio. Complete no- textbook Code and Theory and used parts, assemblies, etc. Carton packed: 50 lbs. correspondence license courses. Ron Reed Electronics In- $6.00; 100 lbs. $10.00. F.O.B. Lima. Send for Free BIG Cata- stitute. 12217 Santa Monica Blvd.. Los Angeles. Calif. NEW BIG SPRING '76 CATALOG Free! Over 2,700 log! Fair Radio, Box 1105 -E, Lima, Ohio 45802. 90025. top values coast to coast! UNITED FARM AGENCY. 612 - NO FCC LICENSE? Tried every way but the right way? Its EP, West 47th, Kansas City, MO 64112. time for Gens Tech. Home Study. Free Catalog. 5540 Holly- SHORTWAVE LISTENING wood Blvd., Los Angeles, Calif. 90028. DO -IT- YOURSELF FCC LICENSE STUDY GUIDE -new. 377 pages, includes 1465 FCC -type questions, with answers and discussions,

"DXing I LOVE YOU" colorful Jacket Patches, $1. Benefit covering third, second, and first class radiotelephone TELEPHONES, All Types. Equipment, Supplies. Keyed, Handicapped Aid Program. SWL Guide, Syracuse, NY exams. $8.95 postpaid. GSE, 2000 Stoner Avenue. Los Regular. Decorator. Catalog, 50 cents. Box 1654J, Costa 13219. Angeles, Calif. 90025. Mesa, California 92626. JANUARY 1976 117

www.americanradiohistory.com CLASSIFIED ADVERTISING ORDER FORM b0K0sdie Please refer to heading on first page of this section for complete data concerning terms, frequency discounts. closing dates. etc. dnah frednrtOOq3 ,be E /n N W 1 2 3 4 5 o', fase -GO%c mietet 7n d 6 7 8 9 10 104 ns . on °63r

11 12 13 14 15 - - can nl 18 17 18 19 20 '= "L» to ¡S rhc4 21 22 23 24 25 CATALOG PRICES 26 27 28 29 30 NUMBER DESCRIPTION 1 -10 11 -99 ' 13 -00171 12 pos. rt. angle connector .60 .55 31 32 33 34 35 13 -0002 12 position wafer .60 .55 wen COUNT: Include name and address. Name of city (Des Moines) or of state (New York) counts as one word each. Zip Code numbers not 13 -0003 9 pos. rt. anale connector .60 .55 counted. (Publisher reserves right to omit Zip Code if space does not permit) Count each abbreviation, initial, single figure or group of figures or MC 14435 MC 4O8L. letters as a word. Symbols such as 35mm, COD, PO, AC, etc., count as one word. Hyphenated words count as words. Telephone numbers two 5 two .e n, d 1il Ao ,p..e.,e, system for {lame w. and Dv MS B' POWER SUPPLY count as two words: as three words with area code. CORDS *""5ema'" fso. DO Grev 81.45 ea Words $ 2.00 (Commercial Rate) $ 1.20 (Reader Rate) 14M4a14 NATIONAL CLOCK CHIP 415 aM"WENOIII --LINEAR Payment of S enclosed for insertion(s). ELECTROLYTIC CAPACITORS NE501A 2.80 CHARGE American Express BankAmericard Master Charge Diners Club PLEASE ORDEN IN NULTIPLet ITEM °`' "" NE555A .50 " WORKING e A71OCA .60 for insertion(s). You will be billed monthly. m IuF1 a VOLTS DC 10 `16,35,50 .16 A741V .40 Account # Expiration Date 1.10 20 '16,35,50 36 A747CA A748CV .74 30 16 t6 Master Charge Interbank # (4 digits above name) 1.00 50 '16.35 22 A723CA SIGNATURE MUST BE PROVIDED BELOW MC1468L 390 100 '16,35.50 .25 PRINT NAME 200 16 .22 Red Ld Mtg. Har dwer 500 16 34 ADDRESS 1000 16 .52 TI -3,4 2200 16 1 -1° n_1°° CITY STATE ZIP SPecler ONE '80 .35 I .29 SIGNATURE PE-176 MINIATURE FILM CAPACITORS

VALUE PRICEE TABE WU 114 CET 81100 001 to 10 .W BUSINESS OPPORTUNITIES .0047 10 10 09 EMPLOYMENT OPPORTUNITIES 01 10 10 on Eare made .55 11 .15 W Ine.n,h Pn Con .1 .24 .21 25 ml A 11 ...^. .". .22 .20 .28 25 4, too v I MADE $40,000.00 Year by Mailorder! Helped others make ELECTRONICS /AVIONICS EMPLOYMENT OPPORTUN- money! Free Proof. Torrey. Box 318 -NN, Ypsilanti. ITIES. Report on jobs now open. Details FREE. Aviation Michigan 48197. FIXED POWER SUPPLY KITS Employment Information Service. Box 240E. Northport. IPedb-to,.: P1{15 F1215 FINIS FREE CATALOGS. Repair DIGITAL New York 11768. air conditioning, refrigeration. Input Voluge 1505000E1 105125v 105 I25v 110125v Tools. supplies, full instructions. Doolin. 2016 Canton. Output Voltage 5v T 5% 525: 5% 15" : 5% Output Current IT. - 25° CI I.NA M. 1.5A M.X. 1.1A Ma.. CIRCUITS Dallas. Texas 75201. PRICE 014.00 514.50 814.50 CATALOG MUM®ER 1'r MAILORDER MILLIONAIRE helps beginners make $500 INDEFINITE SNORT CIRCUIT PROTECTION Poce mrcWdn ',ed.!. 7402 G.10 Bord All Perl, and Nome weekly. Free report reveals secret plan! Executive (1K1), n 7402 .> 333 North Michigan, Chicago 60601. 7404 .34 1 .1 1 7410 34 PIANO TUNING LEARNED QUICKLY AT HOME! Musical DISPLAY BEZELS ]U] 5

I I knowledge unnecessary. Free Information. -1 Empire CATALOG FILTER NOCE 13114041W 1116 .54 Thu. be7NS we - School. Box 450327. Miami 33145, Nt_sae COLOR T-24 C Mt rnnunt 7117 .51 -- 90580 Red 52.50 1047 142o A2 Wesbc vorne ye e $200.00 DAILY In Your Mailbox! Your opportunity to do L 91080 Red 2.55 2.00 black 7447 1.40 L 91580 Red 7473 what mail -order experts do. Free details. Associates. Box 2.85 300 1,01,0 Filters 82 92080 Red 2.70 4.00 em CNCVlaI 7475 B5 136 -J. Holland. Michigan 49423. 92070 ArMn 2.70 400 pol.ued type 1476 B2 IMSAI 8080 A COMPLETE MICRO -PROCESSOR ... I FREE S Per _.44 7490 02 BOOK "2042 unique proven enterprises." Work C SYSTEM . . . COMPATIBLE WITH THE ALTAIR Oreen _.H 7492 92 BUT OFFERING home! Hayling -B. Carlsbad. CA 92008. Add A 1193 92 COMMERCIAL GRADE PRODUCT 0 e M' 74121 20 -A 74192 - GOLD PLATED CONTACTS 2.201 PADDLE SWITCHES P2 - RELIABLE Il numbernun` - HEAVY DUTY POWER SUPPLY - SUPER STURDY CARD CAGES SOCKETS - 30 DAY DELIVERY Citizens Band TRANSISTORS BASIC COMPUTER INCLUDES CPU, 1K RAM H.D. FRONT PANEL LOW PROFILE CONTROL BOARD WITH EXTRA 8 LED INDICATED OUTPUT Time are SUPPLY, DEALER-DISTRIBUTORS socket. 2N3638A P 5 TO -92 .25 PORT. ALL LIGHTS AND SWITCHES. H.O. POWER from Ti EXPANDER BOARD & CASE. 2N2222A N .5 TO -18 .20 KIT 5439 ASSEMBLED 5631 Send this ad with Letterhead to: NUMBER 2N5133 N .05 TO -18 .25 P ALPHANUMERIC PRINTER FOR PAL ELECTRONICS CO. ` 2N5494 N 7 00 TO -220 1.05 IMSAI 8080 OR ALTAIR 8800 IA 25 2N4401 N .60 TO -92 60 COMPUTERS W. WELDON - PHOENIX, ARIZ. 85017 32 CHARACTERS PER LINE!! 24 40 2N4403 P .60 TO -92 .30 28 125 LINES PER MINUTE!! P 50 TIP32 P 3.00 TO -220 1.05 I NTERFACE KIT - EVERYTHING Il GET RICH with Secret Law that smashes debts and brings MS AI8Y TO CONNECT ÁP 32 RAG OF SO MOLEX PIN NESTERS TO IMSAIL8080 ALTAIR you $500 to $5 Million cash. Free report! Credit 4K1. 333 TRIMMER 8800 - ALL PARTS, INTERFACE North Michigan, Chicago 60601. 7pinaeyl 52.00 BO CABLE. & S. POTENTIO- ASSEMB LED 3138. pin PROPRIETORSHIP -Partnership -Corporation Which is right METERS e $2.25

! ! ALTAIR NEW PROTOBOARD FOR IMSAI 8080 AND for your new Business and how to go about forming it. FOR WIREWRAP OR SOL DrR [UMBERS. ROOM FOR THIRTY 14 OR 16 Thew are 5 /8- diameter MOLEX IC TERMINAL PIN LIMPS TWO TO PIN `HIPS OR THREE 24 PIN C HIPS. I1Mmbwhe0 $5.00. ISSCO. Box 4009. Irving, Texas 75061. la lo, Si to 300 for $260 BOARD HEAT SINK 1 V. REGULATOR ..ORDER KI1 76E000...1:= 5001/4 $420 2001or si,eo et for $3.40 fi001or 55.00 "P.E.'S" CASSETTE RECORDER INTERFACE e poten oometxr 700 for I (SEPT. ISSUE[ 050' 55 80 900 for f1.40 "P.E" CIRCUIT PLUS IIO CONTROL. (NO OTHER BOARD REO'O.I HIGHLY 800 lot 56.60 1000 for WOO PART SCREI 529 KIT 339 ASSEMBLED PROFITABLE -MAN 5 ONE h-.r 334 Reel of 50,000 270.09 THE INTEL DATA BOOK CONTAINS COMPLETE SPECIFICATIONS AND DATA SHEETS ON ELECTRONIC FACTORY VALUEf ONNM REGULATOR CIRCUITS INTEL 8080A AND ALL ASSOCIATED INTEL MEMORY AND PERI 100 500 II( 5K 10K PHERAL CHIPS. ALSOINCLUDESPRELIMINARV SPECS ON "COMING" 100K 500K Investment 50K MC7805CP 5 vor reaul.tor Ina. INTEL CHIPS 157 00744 . .. 5500 unnecessary, knowledge not required, PISA I 0 MC7B12CP 12 w t rpulnor e 1.5A Ines. 2.00 sales handled by professionals. Postcard brings MICE THE TTL DATA BOOK MC7815CP 15 vo t regulator 01.5A me.. 2.011 facts about this unusual 0 E N 102 CONTAINS COMPLETE ELECTRICAL SPECIFICATIONS FOR ALL 7400 opportunity. Write today! SERIES TIC THIS IS THE TTL "BIBLE" 640 papes SI0.00 Barta- DA,Box 248, Walnut Creek, CA 94597. 30 120 127 16 Page DIODES Catalog 1N4001 8/81.00 IB MS {10.00 101n.ln. Or e 154002 13/S1.03 DYETHERPINOUTEHANDBOOKEDTIGN6 MAKE durable building plastic 0,4e.,N. ha. S75 DO add 154148 10131.00 FUNCTIONAL SPECS' CROSS REFERENCE BOSS easily. Waterproof, Fire- ay B ha 25 1N5401 5/52.00 proof. Economical. Bays Laboratory. > e 134m, 13A. 100PIVI 44. Cedaredge. CO ..,e ...a IMS ASSOCIATES. INC. 54N 2 LEANUDROICC ALI F. 94577 II 1/4746-759A 4.3... TERMS: CHECK OR MO., BANKAMERICARD, MASTEACHARGE. 81413. 25% DEPOSIT ON C.O.D. ADD 5S POSTAGE AND PRICES TO HANDLING. SUBJECT CHANGE WITHOUT TRACY DESIGN CORP. CALIF. RESIDENTS. NOTICE RUBBER STAMPS ADD 6.5% SALES TAX IMSAI 15870 SCHAFF ER DETROIT. MI. 48227 . 13131 838.2501 RUBBER ADDRESS STAMPS. Free Catalog. 45 type styles. Jackson's. Dept. K. Brownsville Rd., Mt. Vernon. III. 62864. CIRCLE NO. 24 ON FREE INFORMATION CARO 118 POPULAR ELECTRONICS

www.americanradiohistory.com PRO SPORTS ACTION FILMS -ABOUT YOUR SUBSCRIPTION START A SPORTS FILMS COLLECTION IN 1976. Here's Popular Electronics Your subscription to POPULAR what you can buy for $15.95 ppd per 200' reel of color film ELECTRONICS is maintained Standard or Super 8 your choice of the following Indy on one of "500" official films: 1967 (A. J. Foyt); '68 (Bobby Unser); '69 the world's most modern, efficient (Mario Andretti); or 1970 (Al Unser). Standard 8 only can be computer systems, and if you're like shown on Standard 8 or Dual 8 projectors. B&W Golf films 99% of our subscribers, you'll never choice of Sam Snead "Cut Strokes" or 6 Tommy Armour have any reason to complain about JANUARY 1976 films: "Grip ", "Stands ", "Swing ", "Long Irons ", "Short your subscription service. Irons ", "Traps & Putting ". Standard 8 or Super 8, $5.95 We have found that when corn - ppd while they last. Castle, Columbia or Sportlite films plaints do arise, the majority of them ADVERTISERS INDEX catalogs, 30 cents each (coins or stamps, please). SPORT - occur because people have written LITE, Elect -1, Box 24 -500, Speedway, Indiana 46224. their names or addresses differently at different times. For example, if READER PAGE RECORDS your subscription were listed under SERVICE NO. ADVERTISER NUMBER "William Jones, Cedar Lane, Mid- dletown, Arizona," and you were to OLDIES. 45rpm. Free Catalog. Corny's Record Shop. Box renew it as "Bill Jones, Cedar Lane, 1 A P Products Inc 81 166TA, Mason, Ohio 45040. 25 Ace Electronic Parts 105 Middletown, Arizona," our computer 2 Adva Electronics 117 FREE RECORD COLLECTION Reviewers wanted. Anyone would think that two separate sub- qualifies. We ship you new records to review. You pay 3 Allison Automotive Company 71 scriptions were involved, and it postage. Records are free. Applicants accepted "first Alpha Electronics 100 would start sending you two copies come" basis. Write: Research PE, 6162 Washington Circle, 6 Altai Electronics 109 of POPULAR ELECTRONICS each month. Milwaukee, Wisconsin 53213. 7 American Video Corporation 99 Other examples of combinations of B Ancrona Corp 113 names that would confuse the corn - 9 UK Precision, Product of Dynascan 1 BOOKS AND MAGAZINES puter would include: John Henry 10 Babylon Electronics 117 Smith and Henry Smith; and Mrs. Bell & Howell Schools 24, 25, 26, 27 Joseph Jones and Mary Jones. Minor Beta Electronics 98 FREE Catalog. Aviation and Space books. Aero Publish- 29 differences in addresses can also 61 Breaker Corporation ers, 329PE West Aviation, Fallbrook, California 92028. CREI Capitol Radio Engineering Institute 30, 31, 32, 33 lead to difficulties. For example, to FREE book prophet Elijah coming before Christ. Wonderful 11 Cleveland Institute of Electronics 16 the computer, 100 Second St. is not bible evidence. Megiddo Mission, Dept. 64, 481 Thurston 12 Cleveland Institute of Electronics 64, 65, 66, 67 the same as 100 2nd St. Rd., Rochester, N.Y. 14619. 13 Cobra, Product of Dynascan SECOND COVER So, please, when you write us 14 Continental Specialties Corporation 13 LEARNING ABOUT SYNTHESIZERS. Covers complete about your subscription, be sure to 15 Delta Electronics Co 116 field of Electronic Music. $5.98. LINTON. Box 898P, N. enclose the mailing label from the 16 Delta Products. Inc. 52 Eastham, Mass. 02651. cover of the magazine-or else copy 17 Dip-Key Corporation 112 POPULAR ELECTRONICS INDEXES. Detailed and com- your name and address exactly as Dixie -Hi- Fidelity 28 plete subject indexes available to magazine years 1974. they appear on the mailing label. 18 EICO 97 1973, and 1972. Hundreds of subject references to help you This will greatly reduce any chance 19 Edmund Scientific Co 106 quickly find that special project, article or product test. 20 Edmund Co 120 of error, and we will be able to ser- Scientific 1972, 1973 and 1974 editions $1.50 each. All three editions 21 74 75, 76, 77 vice your request much more Electronics Technical Institute only $4.00. INDEX. Box 2228, Falls Church, Va. 22042. Florida Institute of Technology 97 quickly. 22 Handic USA Inc 6 5 Heath Company 5 HYPNOTISM 24 IMS Associates, Inc 118 26 Illinois Audio 102 Details 27 International Electronics Unlimited 108 SLEEP learning. Hypnotic method. 92% effective. GOVT SURPLUS 28 lames 110,111 free. ASR Foundation, Box 23429EG. Fort Lauderdale, 33 Johnson Co., E.F. 101 Florida 33307. Electronic "Super- Buys" 29 Lafayette Radio Electronics 34 FREE Hypnotism. Self- Hypnosis. Sleep Learning Catalog! 30 Labtronics 100 Drawer H400, Ruidoso, New Mexico 88345. 115 -VAC, 6 -DIGIT COUNTER 31 Locksmithing Institute 102 AMAZING self- hypnosis record releases fantastic mental I - - Hundreds 32 McIntosh Laboratory Inc 45 1 ITEM #21-960 Forum (AA1). 333 power. Instant results! Free trial. Write' of uses. Counts 1 for each pulse. 34 MITS 2 North Michigan, Chicago 60601. Capable of 600 pulses per minute. 35 Martin Research 89 Use with any contactor. 115 -volt, NRI Schools 8.9, 10, 11 60 -cycle coil. 3 -3/4" x 2-1/2" e 36 National Camera 100 TREASURE FINDERS $4.97 1-1/2". 12 lbs. 1 National Technical Schools 84, 85, 86, 87

ï 8 oz. I 37 New -Tone 116 24-VDC, 6 -DIGIT COUNTER $3.97 38 Olson Electronics 102 FREE FACT -FILLED CATALOG! World's largest selection! os ITEM Y21.1019 1 Useful for some type applications 112 39 Olson Electronics Metal detectors starting at $79.50. Two year guarantee! above unit operates on 24 -VDC. 3.118" x 1.5/8 " x 1 40 Parrott Precision Electronics 14 Three factories, U.S.- Canada. 1,200 dealers - Service DRIVEN COUNTING UNIT 41 Pathcom Inc 15 Centers nationwide. Finest instruments at any price! MOTOR 63 Phase 40 Linear Budget Terms. Dealer inquiries invited. Write: White's I ITEM #1 -984 I - - Sophisticated 42 Pickering & Co THIRD COVER Electronics. Inc. Dept. PD6O. 1011 Pleasant Valley Road. control unit. Can be used to switch 43 Pickering & Co 28 Sweet Home. Oregon 97386. three ccts. in sequence, odd action to - 115 electrical signs, con operate as a 44 Poly Paks TREASURE FINDER locates buried gold. silver, coins, 45 Processor Technology 90 counter. Operates on I15 -VAC. Has treasures. 6 powerful models. Instant financing available. -VDC solenoids, AC motor 46 RCA Electronic Instruments ...... 82 three 24 Write or call for free catalog. Phone (713) 682 -2728 day or wheels, clutches, gears, 47 Radio Shack 17 number night. Dealer inquiries invited. Relco, Dept. AA20, Box concocts, etc. 7' x 7 x 4 ". 98 $3.97 (5 ) 48 SAE 10839, Houston. Texas 77018. 49 S D Sales Co 107 HIGH VOLTAGE SPARK UNIT 50 Sencore 80 ITEM #15 -958 I ' - Use for 51 Shure Brothers Inc 73 MAG NETS I many spectacular experiments in 52 Solid State Sales 114 electronics, physics, chemistry. 53 Southwest Technical Products Corporation 7 30,000 VAC output from 115 -VAC. -20 or 10 bar, or 2 stick, 54 Sphere Corporation 95 MAGNETS. All types. Specials disc. Fast, intense spark jumps 1/2" tr 55 Stereo Discounters 28 $1.00. Magnets. Box 192 -H. or 8 assorted magnets. x ( 6 lbs. 3/4 ". 6" a 4" 3". I $S29 56 Surplus Center 119 Randallstown, Maryland 21133. 57 Systems Research, Inc 82 CHOPPED LIGHT, MICRO -PHOTOCELL DEVICE TEAC Corporation 23 ITEM Reflec- MISCELLANEOUS I #22 -1030 I - - Tracy Design Corporation 118 tive blades driven by 30 RPM, 58 Tri -Star Corporation 45 115 -VAC synch. motor post 59 Triplett 63 micro -photocell 720 times per min. WINEMAKERS: Free illustrated catalog yeasts. equipment. 4 United Audio Products, Inc FOURTH COVER Chopped signal can be used to Box 12276P. Minneapolis, Minn. 55412. 62 Voltronix 99 Semplex. trigger other devices. Contains

$4.71 ( 2 lbs. ) thermistor. 4" x 4" x 3' CLASSIFIED ADVERTISING LEARN MORE SOUND OPERATED SWITCHING MODULE 106. 108. 112, 114, 116, 117, 118, 119 ABOUT ( ITEM #11 -1256 1 - - Sound into crystal PSYCHOLOGY mike and amplifier triggers SCR ( GEC10601 FREE... Make sound controlled relays to open doors, $ Write for FREE information on the unique energize actuators, alarms, etc. Operates on 1 .49 8 quarter credit course in introductory Psychology 1 6 -VDC. x 1" a ( 4 oz. 1 developed by the University of California and 3- ". ALL ITEMS F.O.B. LINCOLN PSYCHOLOGY TODAY magazine SEND 25 -CENTS ( coin or stomps 1 FOR BARGAIN CATALOGS Write STUDY PROGRAM, Dept. CL, Rm. 715, One Park Avenue, N.Y., N.Y. 10016. Lincoln, Nebraska SURPLUS CENTER PE-16 Zip Code 68501

CIRCLE NO. FREE INFORMATION CARD JANUARY 1976 56 ON 119

www.americanradiohistory.com WHEN YOU COME TO PHILADELPHIA BE SURE 10 SEE LIVE IN THE WORLD FREE BICENTENNIAL LIGHT SHOW IN BARRINGTON, N ONLY 10 MINUTES AWAY AT OF TOMORROW ...TODAY! EDMUND FACTORY STORE PLUG IN 200,000 And our FREE 164 PAGE CATALOG is packed with CANDLEPOWER! exciting and unusual values in electronic, hobby Powerful 12v emergency light projects big and science items - plus 4,500 finds for fun, study straight beam visible for 2 miles. Plugs into car's or profit cigarette lighter; only 31/2 lbs. Great for ... for every member of the family. motorists, outdoorsmen, emergency crews, security men, campers. Super bright 200,000 v. A BETTER LIFE candlepower G.E. aircraft landling light in a rugged weatherproof steel housing with baked enamel finish, steel lens grate, polished chrome STARTS HERE -plated reflector, on /off switch. 15 ft. extension cord; 61/4 dia. x 111 /s ". Keep it handy! Stock No. 72,093 AV $22.95 Ppd. FUEL MISER RECLAIMS HEAT CAN'T SLEEP, RELAX? Save your 40% wasted heat to warm a basement, garage or rec room at no extra cost! Instead of TRY THIS! going "up the chimney" it goes where you want it. Remove part of furnace exhaust pipe, slip Heat Electronic sound conditioner simulates 4 Exchanger in. At 125' fan automat. forces kinds of soothing sounds of ocean surf and rain. "White clean air through unit which heats to over 200 °F., can be ducted to 20 ft. from unit. 1/ sound" helps mask unwanted 110v AC. Instructions. noise, adds restful, intriguing background sound. Program the solid -state unit to No. 19,194V (s/e" DIA.) Shpg. 17 Ib $106.00 FOB your own need, 2 surf, 2 rain; or "white sound ", proven by medical tests to have No. 19,195AV (6" DIA.) Shpg. 17 Ib. $106.00 FOB analgesic effects. Great for meditation, restlessness, sleeplessness psychology. No. 19-198AV (7" DIA.) Shpg. 17 Ib. $106.00 FOB (A) -No. 71,997AV....(71/2 u 7 n 31/2") 110V AC $89.95 Ppd. (B) -AS ABOVE, BUT "WHITE SOUND" ONLY

No. 71,980AV . .. (6" Rd. 31/2- Hi) $28.00 Ppd. SUPER POWER FOR ANY RADIO KNOW YOUR ALPHA FROM THETA!

New antenna assist turns a tiny transistor into a For greater relaxation, concentration, listen to tiger, has pulled in stations up to 1000' miles your Alpha -Theta brainwaves. Ultra- sensitive away! Just set beside radio (no wires, clips, electrode headband slips on /off in seconds - eliminates need for messy creams, grounding) and fine etc. Atch'd -tune Select -A- Tenna's dial to amplifier, filters brainwaves, signals beep for to same frequency - "gangbusters "! ea. Alpha or Theta wave passed. Monitoring Great for clearing weak signals in radio depressed areas, off -coast islands. button stimulates Alpha sound; audio & visual crowded frequency stations. Solid state -uses no electricity, batts., tubes. (L. E.D.) feedback. Reliable, easy -to-use unit comparable to costlier models. Com- pletely safe. Comprehensive instruction booklet. Stock No. 72,095AV $15.95 Ppd. No. 1635AV (8 3 4 "; 24 oz.) $149.50 Ppd. ULTRA SELECT -A -TENNA DELUXE "ON" TIME MONITOR- Measures and records No. 72,147AV (OVER 1000 MI.) $22.95 Ppd. No. 1652AV (15 10 6 ") $299.50 Ppd. No. 71809AV LOW COST "STARTER" UNIT $55.00 Ppd. DO -IT- YOURSELF KIT No. 61,069AV $34.95 Ppd. 50- 150 -300 POWER MICROSCOPE LOW COST 7X AmazingValue- 3AchromaticObjectiveLenses INFRA -RED VIEWER on Revolving Turret! Color- corrected, cemented achromatic lenses in objectives give farsuperior For infra -red crime detection surveillance, se- I.R. laser results to single lenses usually found in this curity system alignment, detection, checking, nite wildlife study, any work req. I.R. microscope price range. Results are worth detection & cony. to visible spectrum. Self cont. the difference! Fine rack and pinion focusing. Imported, scope w /everything incl I.R. light source. 6v Stock No. 70,008AV or 12v power, 6032 I.R. converter tube, f/4.5 objective lens, adjust. triplet $45.00 Ppd. eyepiece. Focuses from 10' to infinity. MOUNTED 500 POWER OBJECTIVE: No. 1659AV (11 ' 141/4.31 $285.00 Ppd. Threaded achromatic lenses, 3mm F.L. WITHOUT LIGHT SOURCE Stock No. 30,197AV $9.75 Ppd. No. 1663AV $225.00 Ppd.

SEE MUSIC IN 41/4x' ASTRONOMICAL PULSATING COLOR TELESCOPE moon rings New See craters, of Saturn, double stars. 3- Channel Color Organ adds to music listen- New equatorial mount. f:10, 1i4 wave mirror ing pleasure, lets you modulate 3 independent (Pyrex "). Gives theoretical limit of resolution. strings of colored lamps with intensity of your Rack & pinion focusing. Aluminum tube, 6X music to create an audio "light show." They flash, finder. 1" F.L. 45X Kellner achromatic eyepiece vary in brightness related to music's rhythm, and Barlow lens to double & triple power up to pitch, volume-pulsating lighting performance to 135X. Free Star Chart plus 2 Books. music! Fully assembled & priced half that of others, the Edmund Sound To Light Control is a Stock No. 85,105AV (Shipping Wt. 42 lbs.) $159.50 FOB terrific value. Plug in, turn on! 41/2 WITH CLOCK DRIVE No. 85,107AV $199.50 FOB 6 REFLECTOR TELESCOPE (48X to 360X) No. 85,187AV $249.50 FOB No. 42,309AV..,(ASSEMBLED) $17.95 Ppd. 6' WITH CLOCK DRIVE No. 85,086AV $285.00 FOB No. 42,336AV...(UNASSEMBLED) $13.95 Ppd. 3 DELUXE REFLECTOR (30X to 90X) No. 80,162AV $ 89.95IPpd. STANDARD 3 REFLECTOR No. 85,240AV 5 59.95 Ppd. MAIL COUPON FOR GIANT FREE EDMUND SCIENTIFIC CO. 300 Edscorp Building, Barrington, N.1.08007 How Many Stock No. Description Price Each Total EDMUND CATALOG! PLEASE SEND GIANT 164 PAGES . MORE THAN FREE CATALOG "AV" UNUSUAL 4500 BARGAINS Charge my BankAmericard Completely new 1976 ed,fion. New atens, categor,es, dlustwelons Dozens Charge my Master Charge 'Add of electrical and electromagnetic ports, accessories. Enormous selection of Handling Chg $1 00, Orders Under $5.00, 50g, Orders Over $5.00 Astronomical Telescopes. Unique lighting and ecological items. Micro - Binoculors, Magnifiers, Magnets, Lenses, Prisms. Hard-to-get- Interbank No.{ surplusscopes, bargains. Ingenious scientific tools. 1000's al components. IWPAMERIDAPD astet cna,ge I enclose check D money order for TOTAL $ EDMUND SCIENTIFIC CO. My Card No. Is I 1 I ©tl® 300 ildml, Barrington, N. 1. 01007 Please rush Free Giant Catalog "AV" II Signature Card Expiration Date Name, 30 -DAY MONEY -BACK GUARANTEE. Name Address You must be satisfied or return Address L,fy Sute =,p any purchase in 30 days for full refund. *515.00 minimum City State Zip

120 CIRCLE NO. 20 ON FREE INFORMATION CARO POPULAR ELECTRONICS

www.americanradiohistory.com We'reWe're#1 and critics totally agree!

HIRSCH -HAUCK LABS ... Stereo Review 66 The Pickering XUV /4500 -Q is obviously one of the best phono cartridges presently available. There are few stereo cartridges that can out- perform it in any of its individual characteristics, and we know of none that could be said to be a better stereo /CD -4 pick -up."

B. V. PISHA ... Audio Magazine "The Pickering XUV /4500 -Q ranks among the top cartridges for stereo, SQ, QS and CD -4. The sonic clarity is exceptionally good with superb t-ansient and applause response, and good defirition, particularly in the low bass region." To sum up, we can recommend the Pickering XUV /4500 -Q cartridge without reservations, based upon our laboratory and listening tests"

MAURICE HOLTHAM ... Canadian Stereo Guide "In fact the reproduction of all material ... stereo, CD -4 and matrix ... was absolutely superb. Good recordings were reproduced with outstanding fidelity and clarity, and tracking was secure at one gram with even the most heavily modulated bands. Solo instruments and voice were rendered with exciting realism; large orchestral and choral works came through in all their magnificence."

Hi -Fi Stereo Buyers Guide In both stereo and CD -4 one of the most outstanding under any program conditions. Sound so clean and crisp it almost hurts." "This pickup is a perfect example of why measurements cannot truly express the sound quality from a transducer; though the measurements are good, the sound quality was rated by the entire listening panel as superb."

The specifications of the XUV/4500 -Q are so exciting that we hope you will write to Pickering and Company, Inc., Dept. PE,101 Sunnyside Blvd., Plainview, New York 11803 for further information. le PICKERING "for those who can hear] the difference"

Reprinted by permission of Audio, Canadian Stereo Guide, Hi -Fi Stereo Buyers Guide and Stereo Review Magazines.

CIRCLE NO 43 ON FREE INFORMATION CARD www.americanradiohistory.com The least you should require of a turntable is assurance that its tonearm can track flawlessly with the most sensitive cartridges, and that its drive system will introduce no audible rumble, wow, or flutter. To accept less means risking damage to your expensive records and producing sounds from your system which were never recorded. Dual precision Happily, the lowest- priced Dual, the 1225, is the erfect example of Dual's basic design concept: to build every turntable with more precision than you are ever starts automatically likely to need. The 1225 is a fully automatic, single -play turntable with multi -play facility. Its vernier-adjustable, at $139.95. And low -mass counterbalanced tonearm can track flawlessly at as low as one gram. Stylus pressure is applied exactly semi-automatically as in every Dual, around the vertical pivot and perpendicular to the groove, maintaining perfect balance in all planes. Anti- skating force is also applied exactly as at $199.9 in every Dual, with separate calibrations for conical, elliptical and CD -4 styli. Other features the 1225 shares with all other uals include pitch -control and cue- control damped in oth directions. The hi- torque motor maintains speed within 0.1% even when line voltage varies as much as 20 %, and the hefty 3% lb.,10 %" platter provides effective flywheel action to minimize the audible effect of any speed variation. The newest Dual, the 510, is a single-play turntable with a unique semi -automated tonearm. A mechanical sensor indicates when the tonearm is positioned precisely over the lead -in groove of a 12" or 7" record. The tonearm remains suspended over the record until lowered by the cue -control; it cannot be dropped accidentally. At the end of play, the tonearm is automatically lifted by the cue -control and the motor shuts off. In all other respects, the 510 is essentially the some as other full -sized Dual models. The 83/" tonearm is mounted in a newly deigned four -point gimbal suspension, and the dynamically -balanced cast platter is driven by an 8 -pole synchronous motor via a precision -ground belt. Pitch is variable over a 6% range (a semitone) and can be conveniently set to exact speed by means of a built -in illuminated strobe, read directly off the rim of the platter. Now all you need decide is which way you want Dual precision: automatically or semi -automatically. (And whether you will ever want to play two or more records in sequence.)

Dual 1225, less than $140, less base. Dual 1226, similar but with cast platter and rotating single -play spindle. Less than $170. Dual 1228 with gimballed tonearm, synchronous motor, illuminated strobe, variable tracking angle, less than $200. Dual 510, less than $200, less base. Full -size belt -drive models include: Dual 601, fully- automatic, less than $250. Dual CS601, with base and cover, less than $270.); Dual 1249, ully -automatic, single -play /multi -play, less than $280.

Dual ed Audio Products, 120 So. Columbus'Á' .; Mt. Vernon,'N.Y. 10553 Exc'usive U.S. Distribution Agency for Dual CIRCLE NO. 4 ON FREE INFORMATION CARO www.americanradiohistory.com