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PLUS: é Hobby Corner Service Clinic * State -Of -Solid State Communications Corner * Equipment Reports www.americanradiohistory.com THE NEW TRIPLETT DMM FAMILY

When you're shopping for digitals, MODEL 3400 be sure to check out these Triplett Multimeters. They're loaded $125 MODEL 3410 Digital with extras that extend multimeter $140 MODEL 3450 life and make your job a lot easier $150 and safer. MODEL 3400 ... Overload protected to 600 volts on ALL ranges, Typical DC accuracy 0.2%, Hi/ Low Power Ohms, Typical battery life 500 hours with low battery SAVE $10.00 indication. Price only $125. MODEL 3410 ... Overload protected to 1000 volts on Purchase one of the Model 3400 Series DMM volts and ohms with no fuse blow, Typical DC accuracy between March 15, 1982 and June 15, 1982 and 0.2%, other features similar to Model 3400. Price only receive a $10.00 rebate. $140. TO RECEIVE REBATE, YOU MUST MODEL 3450 ... Audible continuity plus actual reading, Overload protected to 1000 volts on 1. Distributor identified, dated sales resistance Typical DC accuracy receipt (Non -returnable) volts and ohms with no fuse blow, Power Ohms, Typical battery life 500 SEND 2. Warranty Card from back of Instruc- 0.15%, Hi/ Low $150. tion Manual. hours with low battery indication. Only 3. This completed form. Triplett's over 75 years experience is evident in the engineering firsts included in these digital testers. Plus a TO: Model 3400 Series Rebate Offer full ONE YEAR WARRANTY. For a free no -obligation Triplett Corporation demonstration, contact your Triplett distributor, Mod - Bluffton, OH 45817 Center or Representative. ADDITIONAL TERMS Rebate requests must be postmarked by July 1, 1982, or returned refused. Offer good only in U.S.A. and void where prohibited, taxed or TRIPLETT restricted by law. Distributors not eligible for rebate. Triplett Corporation, Bluffton, OH 45817 Allow 6-8 weeks for your rebate check. (419) 358-5015, TWX (810) 490-2400

NAME Triplett performance .. . COMPANY ADDRESS a tough act to follow CITY STATE ZIP CIRCLE 30 ON FREE INFORMATION CARD CIRCLE 31 FOR in -Plant Demonstration

www.americanradiohistory.com The satellites are there. And all you need is an earth The packages are priced very attractively. station to put the signals to work for you. It's a very real opportunity for you and your We have a complete new selection of packages- customers to make a good profit. dishes, electronics, associated MATV equipment, If it sounds good, call us toll -free for more and all-that you can sell and install wherever you've information. put in MATV systems. Hotels. Motels. Nursing homes. In New Jersey Hospitals. Condos. Apartments. 800-631-5491 20 679-4000

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www.americanradiohistory.com Why use their flexible discs: Athana, BASF, Control Data, Dysan, IBM, Maxell, Nashua, Scotch, Shugart, Syncom, 3M, Verbatim or Wabash when you could be using MEMOREX high quality error free discs? CE quant. 100 price Product Description Part # per disc ($) 8" SSSD IBM Compatible (128 B/S, 26 Sectors) 3062 2.09 8" SSSD Shugart Compatible, 32 Hard Sector 3015 2.09 8" SSDD IBM Compatible (128 B/S, 26 Sectors) 3090 2.74 8" DSDD Soft Sector (Unformatted) 3102 3.14 8" DSDD Soft Sector (128 B/S, 26 Sectors) 3115 3.34 8" DSDD Soft Sector (1024 B/S, 8 Sectors) 3104 3.34 8" DSDD Burroughs B-80 Comp., 32 Hard Sector 3092 3.34 51/4" SSSD Soft Sector (Unformatted) 3401 1.94 51/4" SSDD Soft Sector w/Hub Ring 3481 2.34 51/4" SSDD 10 Hard Sector w/Hub Ring 3483 2.34 51/4" SSDD 16 Hard Sector w/Hub Ring 3485 2.34 51/4" DSDD Soft Sector w/Hub Ring 3491 3.09 51/4" DSDD 10 Hard Sector w/Hub Ring 3493 3.09 51/4" DSDD 16 Hard Sector w/Hub Ring 3495 3.09 SSSD = Single Sided Single Density,. SSDD = Single Sided Double Density DSDD = Double Sided Double Density

Memorex Flexible Discs...The Ultimate in Memory Excellence Quality Quantity Discounts Available Memorex means quality products that you can depend High Quality Memorex Flexible Discs are packed 10 discs to a on. Quality control at Memorex means starting with the carton and 10 cartons to a case. Please order only in best materials available. Continual surveillance through- Increments of 100 units for quantity 100 pricing. We out the entire manufacturing process. The benefit of are also willing to accommodate your smaller orders. in media Error Memorex's years of experience magnetic pro- Free Quantities less than 100 units are available in incre- duction, resulting, for instance, in proprietary coating ments of 10 units at a 10% surcharge. Quantity formulations. The most sophisticated testing proce- discounts are also available. Order 500 or more discs dures you'll find anywhere in the business. at the same time and deduct 1%; 1,000 or more saves VISA 100 Percent Error Free you 2%; 2,000 or more saves you 3%; 5,000 or more t Each and every Memorex Flexible Disc Is certified to be saves you 4%; 10,000 or more saves you 5%; 25,000 or 100 percent error free. Each track of each flexible disc more saves you 6%; 50,000 or more saves you 7% and is tested, Individually, to Memorex's stringent standards 100,000 or more discs earns you an 8% discount off our Order Toll-Free! of excellence. They test signal amplitude, resolution, super low quantity 100 price. Almost all Memorex low-pass modulation, overwrite, missing pulse error Flexible Discs are Immediately available from CE. Our (800) 521-4414 In Michigan and extra pulse error. They are torque -tested, and warehouse facilities are equipped to help us get you 1313) 994-4444 competitively tested on drives available from almost the quality product you need, when you need It. If you every major drive manufacturer in the industry includ- need further assistance to find the flexible disc that's ing drives that Memorex manufacturers. Rigid quality right for you, call the Memorex compatibility hotline. audits are built Into every step of the man manufacturing Dial 800.538.8080 and ask for the flexible disc hotline process and stringent testing result in a standard of extension 0997. In California dial 800-672-3525 ex- excellence that assures you, our customer, of a quality tension 0997. Outside the U.S.A. dial 408-987-0997. product designed for Increased data reliability and Buy with Confidence consistent top performance. To get the fastest delivery from CE of your Memorex Flexible Customer-Oriented Packaging Discs, send or phone your order directly to our Computer Memorex's commitment to excellent does not stop Products Division, Be sure to calculate your price using the CE prices In this ad. Michigan residents please add 4% sales tax. with a quality product. They are proud of their flexible Written purchase orders are accepted from approved govern- discs and they package them with pride. Both their ment agencies and most well rated firms at a 30% surcharge packaging and their labeling have been designed with for net 30 billing. All sales are subject to availability, acceptance your ease of identification and use in mind. The desk- and verification. All sales are final. Prices, terms and speci- top box containing ten discs is convenient for filing and fications are subject to change without notice. Out of stock For Data Reliability-Memorex Flexible Discs storage. Both box labels and jacket labels provide full Items will be placed on backorder automatically unless CE Is information on compatibility, density, sectoring, and Instructed differently. Minimum order $50.00. International record length. Envelopes with multi -language care and orders are Invited with a $20.00 surcharge for special handling handling instructions and and color -coded removable In addition to shipping charges. All shipments are F.O.B. Ann Arbor, Michigan. No COD's please. Non -certified and foreign labels are included. A write-protect feature is available checks require bank clearance. to provide data security. Mall orders to: Communications Electronics, Box 1002, COMMUNICATIONS Full One Year Warranty- Your Assurance of Quality Ann Arbor, Michigan 48108 U.S.A. Add $8.00 per case or Memorex Flexible Discs will be replaced free of charge partlal-case of 100 8 -Inch discs or $8.00 per case or partial ELECTRON ICS' case of 100 51/4 -inch minl-discsfor U.P.S. ground shipping and by Memorex if they are found to be defective In materials handling In the continental U.S.A. If you have a MasterCard or or workmanship within one year of the date of purchase. Visa card. you may call anytime and place a credit card order. Other than replacement, Memorex will not be respon- Order toll -free In the U.S. Call anytime 800-521-4414. If you Computer Products Division sible for any damages or losses (including consequential If you are outside the U.S. or in Michigan, dial 313-994-4444. damages) caused by the use of Memorex Flexible Order your high quality, error free Memorex discs today. 854 Phoenix O Box 1002 D Ann Arbor, Michigan 48106 U.S.A. Discs. Copyright n1982 Communications Electronics" Call TOLL -FREE 18001521-4414 or outside U.S.A. 1313) 994-4444

2 CIRCLE 32 ON FREE INFORMATION CARD

www.americanradiohistory.com II I Radio- THE MAGAZINE FOR NEW Elecironici IDEAS IN ELECTRONICS Electronics publishers since 1908 MAY 1982 Vol. 53 No. 5

SPECIAL FEATURE 57 DESIGN ANALOG CIRCUITS A new 11 -part back -to -basics series. Each month we'll cover analog components and tell you how to apply them. This month, its thermistors and varistors. Mannie Horowitz ON THE COVER

BUILD THIS 49 SATELLITE TV RECEIVER Build this high -quality satellite TV A high quality receiver for under $500. Add an antenna and receiver for under $500. Add a an LNA for a complete satellite earth station. David Becker satellite TV antenna and LNA for 54 AUTOMATIC POWER SWITCHER a complete TV earth station. The An easy -to -build elegant solution to having to throw multiple kit comes with a pre -aligned IF power switches. Gary McClellan strip and LNA power supply. Get 64 UHF -TV PREAMP started building your satellite re- Part 2. Improve UHF reception with this 2 -stage amplifier. ceiver today. Turn to page 49. Ray Pichulo

71 VIDEO TITLER Part 2. Add titles to your home video movies with this alphanumeric character and graphics generator. Michel Champagne

TECHNOLOGY 4 VIDEO ELECTRONICS B1 Tomorrow's news and technology in the quickly changing industry. David Lachenbruch

22 SATELLITE TV NEWS 1 The latest happenings in Communications technology. HOW TO DESIGN analog circuits is a new 11 - Gary H. Arlen part series on analog components and how to apply them. This month, thermistors and varis- 91 STATE OF SOLID STATE tors are covered. The story starts on page 57. One IC voltage conversion. Robert F. Scott

CIRCUITS AND 67 DIGITAL FILTERS COMPONENTS Here's a look at how analog signals are filtered using digital techniques. Arthur Makosinski

80 HOBBY CORNER A new contest and notes from the mailbag. Earl "Doc" Savage, K4SDS

102 NEW IDEAS A word counter for your typewriter.

VIDEO 61 IMPROVE VIDEO SOUND A look at several methods to improve the sound quality of your home video movies. Len Feldman

94 SERVICE CLINIC Troubleshooting IC's. Jack Darr AUTOMATIC POWER SWITCHER solves the "" 96 SERVICE QUESTIONS problem of having to turn on multiple power R -E's Service Editor solves technicians' problems. switches in your hi-fi or computer system. Throw one switch and the power switcher does the rest automatically. Construction starts on TEST EQUIPMENT 77 TESTING FOR SAFETY page 54. Here's a look at how the Underwriters Laboratories check the safety of test equipment and what the UL label means. Jack Darr

Radio -Electronics, (ISSN 0033-7862) Published monthly COMPUTERS 88 COMPUTER CORNER by Gernsback Publications, Inc_ 200 Park Avenue South. Microcomputer memory devices. Les Spindle New York. NY 10003. Second -Class Postage Paid at New York. N.Y. and additional mailing offices. One-year subscription rate: U.S.A and U.S. possessions. $13.00. Canada. $16.00. Other countries. $20.50 (cash orders RADIO 84 COMMUNICATIONS CORNER only. payable in U.S.A. currency.) Single copies $1.25. Shortwave listening on a budget. Herb Friedman 1982 by Gernsback Publications. Inc. All Rights reserved Printed in U.S.A.

Subscription Service: Mail all subscription orders. EQUIPMENT 37 Radio Shack MG -1 Synthesizer changes. correspondence and Postmaster Notices of undelivered 35791 to Radio REPORTS 42 Microtek copies (Form -Electronics Bytewriter-1 Printer Subscription Service. Box 2520. Boulder. CO 80322.

A stamped self-addressed envelope must accompany all DEPARTMENTS 16 Advertising and Sales Offices 26 Letters submitted manuscripts and/or artwork or photographs if their return is desired should they be rejected. We 130 Advertising Index 108 Market Center disclaim any responsibility for the loss or damage of 106 Books 100 New Products manuscripts and/or artwork or photographs while in our possession or otherwise. 131 Free Information Card 6 What's News

As a service to readers, Radio -Electronics publishes available plans or information relating to newsworthy products, techniques and scientific and technological developments. Because of possible variances in the quality and condition of materials and workmanship used by readers, Radio-Electronics disclaims any responsibility for the safe and proper functioning of reader-built projects based upon or from plans or information published in this magazine.

www.americanradiohistory.com VIDEO ELECTRONICS

DAVID LACHENBRUCH CONTRIBUTING EDITOR

DISC Growing pains and early problems have caught up with the infant videodisc industry, resulting in some major changes and realignments. In the optical LaserVision camp, REALIGNMENT the two early prime movers-IBM and MCA-now are out of the action so far as manufacturing is concerned, and Pioneer is in the driver's seat, along with Philips. Plagued by slow deliveries and a high reject rate, DiscoVision Associates, a jointly owned IBM - MCA venture, closed its Carson, CA plant, and now exists only as a patent -licensing company. Pioneer Electronics (Japan) purchased DiscoVision's 50% interest in Universal - Pioneer, which masters and presses optical discs in Kofu, Japan. With the closing of the Carson plant, the only major source of optical videodiscs was Japan, where Pioneer is pressing consumer and industrial discs and Sony is pressing industrial discs only. However, a new U.S. facility for optical discs has just been opened by 3M in Menomonie, WI, and a new firm-Vidisco, headed by David Paul Gregg, an engineer who led the early development of the optical disc-at press time was bidding for the Carson facility. Another company, Quixote Corp., plans to press industrial optical discs using a new fast process. Philips expects to open a disc plant in Blackburn, England this year. North American Philips isn't giving upon the disc. Its Magnavox Magnavision player, which has come in second to Pioneer's unit in features, will be replaced temporarily by one made in Japan by Pioneer around midyear. Probably it wil be sold under Philips' Magnavox, Sylvania, and Philco brand names, until a completely new Philips -developed model is ready in 1983.

RCA DISC Meanwhile, RCA's CED system has also been having its share of troubles. Player sales last year simply failed to meet projections, and competitive compatible players have PRICE been for sale at extremely low prices. However, RCA was surprised by the almost in- SLASHED satiable demand for discs from people who did buy its players; those who owned them for eight months or more purchased an average of 23 discs. As a result, RCA's marketing philosophy seems to have changed to one of wooing disc sales by offering players at low prices. RCA introduced a new model of its basic (monophonic) player with a suggested list price of $349.95, down $150 from its original model (which is virtually the same as the new one), and offered the older model to dealers at an even sharper discount. RCA plans to introduce a stereo -sound model during this spring and a wireless remote version in the fall.

LOOKMAN Sony has introduced a sort of "video Walkman" in Japan, and probably will market it in the U.S. later this year. The 2 -inch picture is provided by the first flat TV tube to be sold on the consumer market. The "FD" (Flat Display) tube resembles a small table -tennis paddle, its electron gun being parallel to the screen rather than perpendicular. The tube itself is about 5/8 -inch thick, 2.17 inches wide, 5.24 inches deep; the TV set is smaller than a paperback book, and can be operated for 21/2 hours on four AA alkaline cells. Another flat TV, using a 3 -inch tube based on the same principle, has been developed by Sinclair Research of the U.K. and is to be built by Timex in Scotland for introduction here this year. Sony's Flat TV sells for about $240 in Japan. R -E

www.americanradiohistory.com "No We've got great news for people thermocouple, the D 804 delivers fully - one else who've been holding out for a high compensated readings in °C from gives you quality, high performance DMM at a -20°C to + 1265°C, for checking many moderate price: Fluke's new nine- heating and refrigeration systems. as function model D 804 is now available Peak hold feature captures functions in at select electronics supply stores. transients: A short-term memory in a handheld With a suggested U.S. price of only the D 804 captures and holds the peak $249 and features you won't find in any reading of a motor starting current. DMM. other handheld DMM, the D 804 is an And more: 0.1% basic dc accuracy, exceptional value. Here's why. conductance, 26 measurement ranges, Now you can Logic level and continuity battery, safety.designed test leads and a move to testing: A real time-saver for one year parts and labor warranty. A up troubleshooting passive circuits in pcb's, full line of accessories is also available Fluke:' cables, relay panels and the like. The to extend the measurement capabilities D804 has a switch -selectable audible of your DMM. tone and visual symbols to indicate Ask your dealer about the continuity or logic levels. powerful, versatile D 804 and the rest of Direct temperature readings in Fluke's new Series D line of low-cost °C: Used with any K -type digital multimeters.

f/1r3r

Sugg .ted U.S. list price If your dealer doesn't carry Series D technical data circle No. 24 Multimeters yet, call this number. We'll be FLUKE 1187-4/D804 happy to tell you who does. 1.800-426-9182 RE 5/82 www.americanradiohistory.com WHAT'S NEWS

U.S. semiconductors E-COM mail starts in a com- now equal Japan's puter, as does much of the other mail today. It is transferred The quality of American 16K to magnetic tape and trans- RAM semiconductors is now mitted by telephone line (or running neck -and -neck with other communications carrier) that of their Japanese counter- to one of the 25 "Serving Post parts, reports Richard W. Ander- Offices" of the system. From son, general manager of the there it is transmitted electroni- Hewlett-Packard Computer Sys- cally to any of the other 24 post tems division. "So far as 16K offices in the net. The electronic , memory parts are concerned, message is then printed out, the contest is now more nearly trimmed, folded, and placed in company -versus -company than envelopes with the address country -versus -country, though showing through a window in we have yet to find a U.S. sup- the front. Delivery is by first- plier who consistently matches class mail. the best of the Japanese," he Twenty-five post offices began says. the service. Others will be Failure rates among units added as expedient. from six suppliers-three of THE CASIO FX-9000P personal those Japanese and three were computer. The basic unit comes with a 4K RAM, a 5.5-inch built-in CRT, very extensive high -resolution graphics, and American-ran from 7 to 30 fail- Casio is powerful mathematical functions for scientific, engineering and statistical ures per 10,000 units, says An- now making operations. derson. Both the highest and a personal computer lowest failure rates were in Casio Inc. has added to its thus simplifying analysis of ex- from Japanese Five new semiconductors line a new sophisticated per- perimental results or business standards suppliers, he said. sonal desktop computer, which data. Hard copies can be ob- published by EIA can be expanded up to 32K bytes tained with an optional graphic The Engineering Department of Random -Access printer. of the Electronic Industries As- United States Mail Memory (RAM). A unique feature is the Powerful mathematical func- sociation announces five new goes electronic 4K CMOS (Complementary Met- tions include standard deviation, or updated standards. Electronic Computer-Origi- al Oxide Semiconductor) RAM regression analysis, and corre- RS -483, "Standard Method of nated Mail (E-COM) became cartridges, on which pro- lation coefficient. Test for Effective Series Resis- part of the postal technology grams can be sotred for quick The system uses a high-level, tance (ESR) and Capacitance of last January. It offers large access for up to three years. semi -compiled, problem -solving Multilayer Ceramic Capacitors mailers considerable economy A high -resolution graphic basic language, CBASIC. An at High Frequencies," is the first in distributing their computer - function can express various easily understood grammer and of its kind for such measure- originated mail. tables, patterns, and graphs, versatile command group make ments. A low-ESR transmission it easy to master. line has been constructed, and Suggested list price for the a mathematical system devised Casio FX9000P is $1,199. Nu- for using it in a resonant mode .."--..... merous options are also avail- to determine capacitor parame- able for the computer. ters, particularly ESR, up to microwave frequencies. Copies RCA videocassette of RS-483 are priced at $10.00. RS -311-A, "Measurement of now plays 8 hours Transistor Noise Figure and Ef- A new RCA long -play tape ex- fective Noise Temperature at pands the recording capability MF, HF and VHF" revises RS - of the "SelectaVision" video 311, adding information neces- cassette recorder to a full eight sary for "effective input noise hours. The new videotape per- temperature" measurements. mits packaging one-third more Copies of RS -311-A are priced tape in a standard VHS cassette, at $6.00 each. resulting in an extension of RS -381-A updates RS -381, playing time from six to eight clarifying the method used to hours in the SLP mode. measure "Q" of a voltage - The deluxe 8 -hour tape cas- variable -capacitance diode in sette, VK330, carries an optional the low VHF range, using an RF E-COM EQUIPMENT UNDER TEST at the RCA Government Communications retail price of $32.95. Two pre- admittance bridge. It is avail- Systems, Camden, NJ. (RCA supplied the equipment for the new system, on vious blank -tape cassettes, the able at $6.50 each. a $31 -million contract.) The system accepts inputs from a customer's computer -generated magnetic tape or from a computer via private telecommuni- VK125 and VK250, with record- RS -490, "Standard Test cations carriers and transmits it to the electronic center designated by the ing times of three and six hours Methods of Measurement for customer, where it is printed, trimmed, folded, placed in envelopes, and de- respectively, will remain in the Audio Amplifiers," replaces EIA livered by first-class mail. line. continued on page 12

www.americanradiohistory.com COMPARE HITACHI TO TEKTRONIX .. .

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No one can match the features or performance at our MARKET -SHATTERING PRICES! Buy with confidence from the nation's largest Hitachi distributor REHITV1050 100 MHz, List $2375.00 REHITV352 35 MHz, List $1150.00 Sale $1595.00 Sale $795.00 REHITV550B 50 MHz, List $1745.00 REHITV202 20 MHz, List $850.00 Sale $1250.00 Sale $595.00

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SPEC TEl Ene 1117110114 NIE/IM/ SPEC TER DEIS /MU CMS! "MUM NI10MI I UMW MIN? PRICE 814110 IIN1.N 411111.01 STUN N10.M CIT I 1I 11 II .N 1I 111n I.11 NI

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Until now, if you wanted a 50MHz or 100MHz dual trace oscilloscope of un- HITACHI Oscilloscopes are innovative oscilloscopes designed and manu- compromising quality, there was only one choice. Now there is a second...out- factured by Hitachi Denshi Ltd. The wide experience gained by HITACHI standing new delay sweep with an established name - the Hitachi V550B and electronic specialists in producing oscilloscopes has resulted in this line of the V1050. modern oscilloscopes featuring wider band width, more compact design and The HITACHI V550B (50MHz) and V1050 (100MHz) offer all the light weight. Through adopting circuitry with linear IC's and logic IC's capabilities you might demand from a lab grade oscilloscope. Cap- plus modern manufacturing techniques, including automatic com- abilities such as a max. sweep rate of 2ns/div (V1050) 5ns/div V5508). ponent -insertion machines. These oscilloscopes offer increased stabil- Also features you may not expect, like sensitivity of 1 mv/div (V550B) ity, improved reliability, excellent performance and enhanced operating .5mv/div (V1050) @ 10MHz, automatic focus correction, and a built-in ease. TV sync separator circuit. The panel layout is designed to create maximum operating ease by The cost? Remarkably reasonable, expecially when you considering measuring processes and operation frequency. The layout compare it to the other leading 50MHz or is divided into three blocks according to 100MHz Dual trace oscilloscopes. It's a price PRIORITY ELECTRONICS ° respective functions identified by dif- breakthrough made possible by using up -to- 9161R Deering Ave., Chatsworth, CA 91311 ferent colors. This convenience -orient- date production techniques and a design ed design for users improves daily Sacked up by over 20 years of ORDER TOLL FREE (800) 423-5922 controllability and drastically reduces oscilloscope experience. a CA, AK, HI CALL (213) 709-5464 operating errors.

TERMS U S VISA, MC. BAC, Check, Money Order. U.S. Funds Only. CA residents add 6% Sales Tax INCLUDE $10.00 FOIE EACH OSCILLOSCOPE for UPS Surface Shipping and Handling. Just in case, include your phone number. Pnces subject to change without notice. We will do our best to maintain these prices through April, 19132. For complete specifications, see our 60 page catalog in the November issue of BYTE or send $1.00 for your copy, today. Sale Prices are for prepaid orders only. CIRCLE 22 ON FREE INFORMATION CARD www.americanradiohistory.com Everjyjbody> making money seuuunselling microcomputers. Somebody s going to make money servicing them. New NRI Home -Study Course Shows You How to Make Money Servicing, Repairing, and Programming Personal and Small Business Computers

www.americanradiohistory.com partment of Labor projects over 100% Become the increase in job openings for the decade Complete Computer Person through 1985. Most of them new jobs You're also trained in writing and created by the expanding world of the debugging both BASIC and advanced computer. machine language programs... gain Learn at Home hands-on experience in the operation in Your Spare Time and application of computers to busi- NRI can train you for this excit- ness and personal jobs. You're trained ing, rewarding field. Train you at home to become the fully rounded, new breed to service not only microcomputers, but of technician who can interface with word processors and data terminals, too. the operational, programming, and Train you at your convenience, with service facets of today's computers. clearly written "bite -size" lessons that You're ready to take your place in the you do evenings or weekends, without new electronic age. going to classes or quitting your present Other Opportunities Training includes the new job. NRI has been giving ambitious TRS-80 Model Ill microcompu- Your training is built around the people new electronic skills since 1914. ter, 6 -function LCD Beckman multimeter, and latest model of the world's most popular Today's offerings also include TV/ the NRI Discovery Lab with hundreds of tests and experiments. computer. It's the amazing TRS-80TH Audio/Video Systems servicing with Model III, with capabilities and features training on our exclusive computer - Seems like every time you turn to perform a host of personal and busi- programmable 25" diagonal color around, somebody comes along with a ness functions. No other small computer TV... Communications Electronics for new computer for home or business has so much servicing and installing microwave, use. And what's made it all possi- software available broadcast, CB, radar, etc... and other ble is the amazing microprocessor, for it, no other is state-of-the-art courses. the tiny little chip that's a computer in itself. Using this new technology, the industry is offering compact, affordable computers that handle things like payrolls, billing, inventory, and other jobs for businesses of every size...perform household functions including budgeting, environmental systems control, indexing recipes. And thousands of hobbyists are already owners, experimenting and developing their used and relied on by so many people. Free Catalog... Mail Card own programs. And it's yours to keep for personal or No Salesman Will Call Growing business use. Send the postage -paid card for Demand You get plenty of practical experi- our 100 -page catalog showing all for Computer ence. Using the NRI Discovery Lab® that courses with equipment and complete Technicians also comes as part of your course, you lesson plans. There's no obligation other This is only one build and study circuits ranging from than to yourself. See how NRI can help of the growth factors in- the simplest to the most advanced. You you grow with the most exciting and fluencing the increasing analyze and troubleshoot using the pro- important new field of the 80's. If card opportunities for qualified fessional Beckman LCD digital mul- has been removed, please write to us. computer technicians. The U.S. De- timeter you keep to use later in your work. Then you use the lab and meter to actually access the interior of your com- NRI SCHOOLS McGraw-Hill Continuing puter...build special circuits and write NRI A I Education Center programs to control them. You "see" t a 3939 Wisconsin Ave. your computer at work and demonstrate I I Ï Washington, DC 20016 its power. We'll give you tomorrow.

(TRS-&i is a trademark of the Radio Shack division of Tandy Corp.)

www.americanradiohistory.com WHAT'S NEWS

continued from page 6

Interim Standard No. 2, which domestic satellites in orbit. Like replaced IHF-A-202 published in its predecessors, Satcoms, I, II, 1978 by the Institute of High and III -R, Satcom IV has 24 Fidelity. Copies are $8.00 each. channels, each of which can RS -475, "Generic Specifica- carry 1,400 voice circuits, one tions for Fiber Optic Connec- FM/color-TV transmission, or 64 tors," covers all fiber-optic con- megabits of computer data per nector types. Price is $7.00 second. The satellites, cover all each. 50 states and Puerto Rico. Copies of all the above are With Satcom IV, RCA Ameri- available from the Standard com has two satellites dedicated Sales Office, Electronic Indus- to cable TV. They have a com- tries Association, 2001 Eye St. bined programming capacity of N.W., DC 20006. A more than 1,000 hours per day. Washington, HEART OF GE'S NEW CIRCUIT for detecting radio signals through extreme free catalog of EIA and JEDEC There are now 22 million U.S. interference is a pair of 128 -point binary -analog computers in the central part standards and engineering pub- homes served by cable TV, and of the chip. That chip was developed by scientists at the GE Research and lications is also available. nearly all of them receive at Development Center at Schenectady, NY. least one satellite -relayed channel of programs. Domestic satellites of the IEEE in San Francisco, some to be an approach toward Interference cut General Electric scientists de- the automatic road control sys- now number fourteen scribed microelectronic device tem of the future. The Message With the launching of RCA's by new GE device that improves radio communi- Center is part of the standard in- Satcom IV on January 14, there At the recent International cations where there's extreme strument panel on the new Con- were the equivalent of 14 U.S. Solid State Circuits Conference noise or interference. tinental. Another version, the The device-called a surface - "Tripminder," is optional on the charge correlator-is intended Mercury -Marquis, Cougar XR-7, for military applications. It will and Ford LTD and Thunderbird. allow effective communication The optional "Trip Computer" under combat conditions where will be available on the European the frequencies are jammed by Ford Granada. the enemy. All three will show the day, The tiny (0.110 x 0.265 inch) date, elapsed trip time, distance NORTH circuit chip will recognize and travels, average speed, and in- amplify specially -coded signals stantaneous and average fuel RADIATOR e AREA IN&SI containing voice communica- consumption. The Continental's INCLINATION tions, while discarding jamming Message Center can also be CONTROL It by a the THRUSTERS noise. does that series of programmed to show esti- multiplying and adding opera- mated time of arrival and dis- PLUME SHIELDS tions-at the rate of over a bil- tance to destination. It also HORIZONTAL lion calculations a second. shows the distance that can be POLARIZATIO Through those calculations, the traveled on the fuel remaining HYDRAZINE REFLECTORS TANKS device can judge the degree of in the tank, as does the Trip gi NSFER ORBIT correlation between incoming sig- Computer.

I ANTENNA APOGEE nals and a special code pro- The systems are produced by MOTOR ^Ar NOZZLE grammed into its memory. Philco-Ford of Canada Ltd., use EARTH If the degree of correlation is National Semiconductor's 8050

LAUNCH VEHICLE high, the device concludes that microprocessors. MATING RING the radio signal contains the LONGITUDE FEEDHORNS IBI desired voice data. Signals with CONTROL 3M's videodisc plant THRUSTERS VERTICAL a low degree of correlation are is now in operation IEAWI POLARIZATION dismissed as noise. The desired $iv.REFLECTORS PLUME data, containing the voice ma- 3M has opened a complete SHIELDS videodisc mastering and repli- SOLAR ARRAY terial, is amplified and passed DEPLOYMENT & cation facility in Menomonie, DRIVE MECHANISM on to a decoder, which reas- PASSIVE sembles them into recognizable WI, (about 50 miles from the NUTATION company's St. Paul headquar- DAMPER words. ters.) The plant was in a modified start-up mode for several months BIFOLD before the opening, while SOLAR ARRAY Ford moving toward testing the sophisticated equip- SUN semiautomatic travel? ment used in 3M's proprietary This year selected car models replication process. in the Ford lineup will carry the The discs are compatible with company's second -generation Magnavox, Pioneer, Sony, and AN RCA SATCOM, with the various parts Identlfiéd. Message Center that seems to Discovision players. R -E

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www.americanradiohistory.com Radio - EDITORIAL Electronics Hugo Gernsback (1884-1967) founder M. Harvey Gernsback, editor -in -chief Larry Steckler, CET, publisher Cable -TV Interference Arthur Kleiman, editor Josef Bernard, K2HUF, technical editor Carl Laron, WB2SLR, assistant editor Jack Darr, CET, service editor Leonard Feldman contributing hi-fi/video editor Robert F. Scott, semiconductor editor Herb Friedman, communications editor You may feel that subscribing to a cable -TV service, will put an Gary H. Arlen, contributing editor end to your TV reception and inteference programs. Unfortunate- David Lachenbruch, contributing editor ly, that is not always true. As it turns out, midband cable -TV chan- Earl "Doc" Savage, K4SDS, hobby editor nels overlap VHF amateur radio bands and, among other sources, offending interference could be from your neighbor's ham rig. But Ruby M. Yee, production manager before you decide to expand your junk box with parts from your Robert A. W. Lowndes, production associate neighbor's rig, let's take a closer look at the problem. A. Mas, production assistant The cable -TV company transmits over shielded coaxial cable Stefanie lines. A "leaky" cable will not only "receive" interference, but will Joan Roman, circulation director also permit the cable signal to escape and be transmitted as inter- Arline R. Fishman, ference. If your cable turns out to be leaky, it's unusually the re- advertising coordinator sult of poor installation. Cover photo by Robert Lewis If you should track the source of your cable interference to your Radio -Electronics is indexed in Applied neighbor's rig, remember that at the same time you are probably Science & Technology Index and Readers Guide to Periodical Literature. interfering with his amateur transmissions. To control that sticky situation, the FCC has restricted the maximum allowable leakage level from the cable to 20 µV -per -meter measured at a distance of Gernsback Publications. Inc. 10 feet from the cable over a frequency range of 54 MHz to 216 200 Park Ave. S.. New York. NY 10003 MHz. Unfortunately, the FCC hasn't aggressively tracked down or President: M. Harvey Gernsback Vice President: Larry Steckler taken action against offending cable companies. If you find interference in your cable -TV reception, report it to the cable com- ADVERTISING SALES 212-777-6400 pany; they're responsible! Larry Steckler Recently, the FCC has proposed to increase the maximum al- Publisher lowable leakage level from 20 µV to 100 µV. In response, the EAST ARRL (American Radio Relay League) has filed a petition against Stanley Levitan the proposed change. In its petition, the ARRL argues that "the Radio -Electronics 200 Park Ave. South Committee's recommendation constitutes acceptance of poor New York. NY 10003 engineering practices of the cable industry and encourages ex- 212-777-6400 an problem." We pansion of existing fully agree and support the MID WEST/Texas/Arkansas/Okla. ARRL in its petition. We hope that the FCC decides against this Ralph Bergen latest proposal and acts to enforce the existing regulation. The Ralph Bergen Co. Inc 540 Frontage Road-Suite 325 Northfield. Illinois 60093 312-446-1444

PACIFIC COAST Mountain States Marvin Green Radio -Electronics 413 So. La Brea Ave. Los Angeles. Ca 90036 azg, 213-938-0166-7 SOUTHEAST ART KLEIMAN Paul McGinnis Paul McGinnis Company Editor 60 East 42nd Street New York. N.Y. 10017 212-490-1021

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Vertical Bandwidth 15 MHz Deflection Factor IOmV/div to 50V/div. ®®oo® 12 calibrated ranges

GuC3E]®® Input Impedance I megohm to pa-allel ocloc with 50 pF QtQ(OßC7 Time Base 0 lµ Sec/div to ib1 Pmil!9M !e 0 5 Sec/city. 21 calibrated ranges Horizontal Bandwidth 200 kHz Trigger Modes Automatic, Internal, External and Line Power Sources Interudi Rechargeable lead acid batteries An unbeatable combination. The all-purpose MS -215 mintscope (lee), and the remarkable External 115 VAC or 230 VAC Touch Test 20 DMM (right). which puts 20 key test functions at your fingertips Now take the lab 50 60 Hz via plug in to the problem. Or the problem to the lab. transformer Size 29"Hx64"Wx80"D Together, the remarkable Touch comes with test leads, temp (74mmx 163mmx 203 mm) Test 20 DMM and MS -215 mini - probe and resistor/capacitor test scope from Non -Linear Systems adapter. Features automatic Weight 31bs (136kg) give you one portable lab instead polarity and overload indications Price $596.00 of a cumbersome collection of plus in -circuit test capabilities. individual testers. They come Works wonders. On -site. In the field. Repairmen use it to trouble- with a trim price, too. Under Touch Test 20 at a glance. shoot DMMs, counters, power $1095. Whatever your trouble- Measurements shooting problems, chances are supplies and signal generators. AC Voltage 10µV to 750 VRMS, 6 ranges. Analyze calculators, microproces- the Touch Test 20 and MS -215 DC Voltage 10µV to 1000 VDC, 6 ranges. sors and electronic games. Test can supply the answer. AC Current 10 µA to 10 A, 4 ranges. DC Current 0 01 pA to 10 A, 7 ranges C-MOS, OP AMPS, oscillators, Touch Test 20. Small wonder. Resistance 10 milli n to 20 meg n, shift registers. And it simplifies The Touch Test 20 weighs barely 7 ranges. measurement of propagation 2 lbs., 4 oz. Yet it puts 20 key test Temperature -40°C to 150°C. -40°F to 302°F, 2 ranges. delays, phase shift and waveform functions at your fingertips. Plus Conductance 0.01 nS to 200 nS (equivalent testing. the ability to measure 10 electri- to 5 megohms to 100.000 2 ranges Both a full cal parameters and 44 ranges. megohms.) warranted year. If Operation's a snap. No dials. Now Capacitance 1 pF to 200µF 6 ranges your work demands test equip- a light touch chooses the function. Tests ment that handles virtually all Diode Diode and transistor junctions normal applications, at a price Large 0.55 LED numbers show in conducting and non- the reading. conducting directions. you can live with, road test the Continuity Audible signal. Touch Test 20 DMM and MS -215 Most innovative portable/bench- Size 2.9"Hx64"Wx75"D miniscope. Just two of the many type DMM available. The Touch (74 mm x 163 mm x 191 mm) exceptional electronic test prod- Test 20 performs a variety of Weight 2 lb 4 oz. (1.02 kg) ucts we've developed in the past mainline tests and measures, Price $495.00 with batteries 30 years. From the specialists in nimbly and accurately. From AC $537.00 without batteries the science of staying ahead. and DC voltage checks to diode and transistor tests and continu- MS -215. A whale of a miniscope. ity analysis. And dozens of tests With the MS -215, 15 -megahertz, Non -Ungar Systems, Inc. Originala of Irte agitar voltmeter. in between. battery/line-operated, dual -trace Box N. Del Mar, California 92014 A shop -proven, field -proven miniscope, versatility and porta- Telepnono (714) 755.1134 lyric 910-322.1132 performer, the Touch Test 20 bility come in a 3 lb. package.

CIRCLE 25 ON FREE INFORMATION CARD

www.americanradiohistory.com If you have put off learning more electronics for any of these reasons, act now! I don't have the time. High school was hard for me and electronics sounds like it may be hard to learn. I can't afford any more education. I have a family now. I'm here. You're there. I've never learned that way before. I'm not sure it will work for me.

2 Read the opposite page and see how you can get started today! 18

www.americanradiohistory.com Be honest with yourself. Are Find out more! the reasons really excuses? You Today. Now. already know There's a card with this ad. Fill it in enough about and return. If some other ambitious electronics to be interested in person has already removed it, use the reading this magazine. So why coupon. not learn more? If you need You'll get a copy of CIE's free encouragement, read on and school catalog, along with a complete package of personal home study see how excuses can be turned information. into results. For your convenience, we'll try to You don't have the time. Be realistic. arrange for a CIE representative to All you have in life is a period of time. contact you to answer any questions Use it. Try to know more tomorrow you may have. than you do today. That's the proven Step-by-step learning includes If you are serious about a rewarding way to success. CIE studies require just "hands-on" training. career, about learning electronics or about 12 hours of your time a week, two The kind of professional you want to be building on your present skills, your hours a day. You probably do have the needs more than theory. That's why best bet is to go with the electronics time. some of our courses include the specialists-CIE. Mail the card or Personal Training Laboratory, which Electronics sounds like it may be hard coupon today or write CIE (please helps you put lesson theory into actual mention the name and date of this to learn. You already know something practice. about Other courses train you to use magazine), 1776 East 17th Street, electronics or you wouldn't be tools of the trade such as a 5MHz reading this. Now, build on that. CIE Cleveland, Ohio 44114. triggered -sweep, solid-state oscilloscope This could be the best decision Auto -Programmed ® Lessons help you you build yourself-and use to practice you've made all year. learn. 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If you are not able to pay full learn it right:' tuition now, CIE will lend you funds on John Cunningham a monthly payment plan. Senior Technical Director You have a family now. All the more reason why you have the responsibility to advance yourself. For the sake of your family. Do you want them to have what you had or have more than you Your FCC License can impress had? The choice is yours. Electronics is employers. a rewarding career choice. CIE can help For some electronics jobs, you must you to get started on that career. have your FCC License. For others, You're there. We're here. How does employers usually consider it a mark in CIE help you learn? First, we want you your favor. Either way, your License is to succeed: You may study at home, but government -certified proof of your you are not alone. When you have a knowledge and skills. More than half question about a lesson, a postage of CIE's courses prepare you to pass stamp gets you your answer fast. You this exam. Surveys show that some may find this even better than having a 80% of CIE graduates who take the classroom teacher. CIE understands exam are successful. people need to learn at their own pace. When CIE receives your completed lesson before noon any day of the week, it will be graded and mailed back the 111111 M M I same day with appropriate instructional help. Your satisfaction with your Cleveland Institute progress comes by return mail. That's I CIE of Electronics, Inc. how CIE helps you learn. T776 East 17th Street, Cleveland, Ohio 44114 Accredited Member National Home Study Council NOW, IF YOU AGREE CIE YES...1 want to learn from the specialists in electronics-CIE. Send me my FREE TRAINING CAN WORK 'CIE school catalog...including details about the Associate Degree program...plus my FREE package of home study information. FOR YOU, HOW ELSE Print Name CAN CIE HELP YOU? 1 Address Apt Cleveland Institute of Electronics is the City largest independent home study school in the world that specializes exclusively State Zip in electronics. Although "big" does not Age Phone (area code) always mean "best;' it is evidence that CIE is a strong, successful institution Check box for G.I. Bill bulletin on Educational Benefits: D Veteran D Active Duty with the people and resources to help you succeed. is MAIL TODAY! RE -36

www.americanradiohistory.com SATELLITE/TELETEXT NEWS

GARY ARLEN CONTRIBUTING EDITOR

QUASI -TELETEXT A new hybrid teletext service that offers electronic listings of tonight's TV programs is now being delivered via the vertical blanking -interval of United Video's transponder 3 SERVICES On Satcom Ill, the circuit that carries superstation WGN. "Electronic Program Guide"-EPG-carries hour -by -hour listings of shows appearing on cable -TV channels of cable systems that subscribe to the service. The EPG line-up is formatted specifically for each cable system, then beamed down the vertical interval, addressed so that each cable system picks up only the listings for its own programming. That makes it possible for systems to tailor the directories-and the ads-to their local needs since each system carries different pay TV channels and other services. Another text service is available on the vertical interval of Satcom Ill Transponder 6, the circuit that carries superstation WTBS. Dow Jones Cable News, a continuous read-out of business and financial news, is the latest addition to the CableText package developed by Satellite Syndicated Systems.

NEW TVRO New home -satellite reception equipment seems to be stabilizing in the price range under $3,000, according to indications at the latest Consumer Electronics Show where EQUIPMENT dozens of devices were on display. Sizable new companies are also getting into the business which could lead to more research, industry clout, and innovation. For example, Boman Industries, a familiar name in the car -stereo market, has plunged into the home -satellite business, offering several packages of equipment that will retail for under $3,000. Its new 3.3 -meter antennas can be put on several new mounts, including a 4 -point AZ/EL mount that permits precision settings for azimuth and elevation positions. Bomar is offering three receivers, with its top -of -the -line model SR -1000 including automatic frequency control, pushbutton controls for satellite -search antenna motor drive, plus a maximum noise of 12 dB. (Boman, 9300 Hall Road, Downey, CA 90241.) Also at CES, the new Downlink 2001 home -satellite system made its debut. The system, being promoted by Interglobal Satellite Systems Inc. (ISSI), includes a motorized antenna, LNA, receiver, and remote control unit-with the package priced at nearly $5,000. (That is about half the price of other fully motorized systems.) ISSI is located at 30 Park Street, Putnam, CT 06260. There's also an increasing market for satellite accessories. For example, Arunta Engineering Corp. has introduced its first receiver intended to pick up the increasing number of stereo -sound programs being distributed via satellite. The Arunta DD -3000 stereo receiver and downconverter carries a $2995 list price, has a noise figure of about 9 -dB maximum, plus several audio metering indicators. (Arunta, PO Box 15082, Phoenix, AZ 85060.)

AROUND THE Video News Conferences: A popular new use of satellite teleconferencing is the "video press conference," which permits reporters around the country to take part in SATELLITE coverage of an event even if they are in a distant city. One of the first such applications CIRCUIT involved MGM/United Artists and their recent movie "Pennies from Heaven." Stars Steve Martin and Bernadette Peters, plus the film's director and screenwriter, were in New York answering questions from columnists and critics in 14 cities around the country. The feed, which was part of the new teleconferencing service of Hilton Hotels, may be the first of a number of similar satellite -fed press conferences run by movie studios. RCA Americom has requested FCC permission to launch Satcom VI. The RCA proposal calls for its sixth bird to go up in January 1985; it will cost $80 million and be the most advanced satellite design, with 24 transponders capable of handling digital audio and video, packet switching, and other services. Meanwhile the saga of Satcom IV, which was launched successfully in mid -January, continues. The FCC declared that RCA's auction to distribute Satcom IV transponders (R -E, March) was not permissible, thus forcing RCA into another plan to allocate the circuits. In other developments, RCA is planning to put up replacements for aging

Satcoms I and II during the next 18 months; the FCC has approved one of those launches. R -E

www.americanradiohistory.com Enter the new age of TV entertainment with the state-of-the-art Heathkit" HOME EARTH STATION SYSTEM The stars are now within your reach and within the reach of your budget. Priced as low as $6,995, the Heathkit SRS -8100 Home Earth Station System puts a wide variety of TV entertainment at your fingertips. Geo - synchronous satellites offer many channels programming movies, nightclub acts, concerts, musical specials, Broadway plays, news and more" most free of cuts, censorship and ccmmercial interruptions.

This home earth station system comes with the The Heathkit SRA-8100-3 Satellite Receiver Kit fea- Heathkit trademark of quality and reliability. tures a special Zenith Space Command Remote The specially -prepared, do-it-yourself SRA-8100-10 Control. It features 24 -channel electronic tuning, drift - Site Survey Kit helps find the correct location for the free reception, built-in memory, a built-in security circuit satellite receiving antenna. Step-by-step assembly (alarm not included) and an attractively -styled walnut - manuals and technical assistance from Heathkil Elec- finish cabinet. tronic Centers make our Earth Station System easy to View exciting satellite programs on the new, state- assemble and install. The SRA-8100-2 Integrated Low - of-the-art Heathkit GR -2500 Color Television. It fea- Noise Amplifier/Down-Coverter, SRA-8100-1 Three - tures maximum picture sharpness with 330 lines of res- Meter Satellite Receiving Antenna and satellite receiver olution, exceptional 112 -channel tuning capability (for electronics are made by Scientific-Atlanta, one of the cable signals), rich four-speaker sound, remote control, world's foremost manufacturers of satellite telecom- optional Space Phone, easy 15 -hour kitbuilding and a munications equipment. great low kit/cabinet system price.

'Federal Communications Commission equipment authorization relating SEE THE LATEST IN HIGH-TECHNOLOGY, to the sale of the Heathkit Earth Station requires the following disclosure: EASY-TO ELECTRONICS "Use of this device may violate Section 605 of the Communications Act -BUILD KIT -FORM of 1934, as amended, through the unauthorized interception and divulg- ence of radio communications for one's own benefit where there is no -It's all in our new, 104 -page Heathkit Catalog. entitlement to its receipt." For your FREE Catalog, write: Viewing of some satellite TV channels may require the customer to obtain Dept. MI permission from, or make payments to, the programming company. Some Heath Company, 020-896, Benton Harbor, 49022 programmers may not grant permission. Some local, state and foreign -or pick up your copy at any of the conveniently -located laws may now or in the future limit the use of this device.The customer is Heathkit Electronic Centers throughout the U.S. responsible for compliance with all applicable laws and regulations.

Heath and Heathkit are registered trademarks of Heath Company. Zenith is a registered trademark of Zenith Radio Corporation. Heath Company and Veritechnology Electronics Corporation are wholly -owned subsidiaries of Zenith Radio Corporation. Heathkit Electronic Centers are operated by Veritechnology Electronics Corporation.

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LOOKING FORWARD work when I had finished, and I had fol- careful, but I proceeded and installed all lowed the instructions religiously, with cer- components successfully, with the excep-

While looking through the February tain exceptions. I am not a novice at tions of those that were marked "not

1982 issue of Radio -Electronics, I found soldering, or at reading diagrams, and used, USA only" because they had not the "Computer Corner" department to accordingly must lay the blame on the kit been supplied, nor were their values men - have a very positive view of computer designer-or the packer. Since what hap- tioned anywhere. As a result, one wire of technology today. pened to me could happen to anyone else, the modulator was left adrift. Extra parts

Other people refer to the advances in I am writing this with the hope that you had been furnished, but there were no computer science as a threat to workers, will make this information available to instructions concerning them.

I thought that the advantages mentioned your subscribers. I thought that a telephone call to Nashua,

in that department show just how much I ordered the kit and received it within which is not far from me here, would clear

we need those machines. I do not think the 30-60 days purchasers were asked to things up in a jiffy. But when I asked the

that they could harm us very much, based allow. On reading the instructions, I saw operator for the number of Sinclair Re - on our economy. references to variations in wiring for the search, Ltd at their address there, she

Soon, I believe, people will be ready to UK, USA, and France, with the statement told me, without hesitation, that many accept computers as a part of their lives. "not used, USA only" applying to the RF people have asked for their number, but K. LYNN BELL, modulator. Apparently the instruction they do not have a telephone. Edwards, MS sheet was one for use in France and the My point in writing to you is to inform UK. Nevertheless, I proceeded to the any future buyers to examine their in - THE SINCLAIR ZX81 assembly. struction sheets; and if they find that cer- The PC board differed from the dia- tain parts are listed as "not used, USA

Recently, I purchased and assembled a gram of parts locations, and that should only"-specifically R32, R33, and D9- Sinclair ZX81 computer, but it wouldn't have cautioned me immediately to be continued on page 32

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www.americanradiohistory.com you that the kit that you received will The article that you are referring to is LETTERS operate in the United States if properly entitled "The Home Entertainment Cen- assembled. If you will return it to us, we ter" that appeared in the January 1982 continued from page 26 will be pleased to repair it free of charge. issue. The 8 -MHz bandwidth specifica- NIGEL H. SEARLE, tion, as pointed out in the article, was they will have little success in getting the Sinclair based on the assumption that since the computer to work, and they might as well Profeel monitor is capable of displaying THE PROFEEL send the whole package back. 80 characters -per-line as opposed to the 40 character-per -line capability of the JOHN K. MITCHELL, I enjoyed your articles on video enter- standard TV set, the bandwidth capability Westwood, MA tainment, but I think that you have misin- terpreted Sony's specs on the Profeel. Ac- of the Profeel monitor is twice that of a The following is a reply to Mr. Mitchell's cording to Bell Laboratories, 340-350 lines standard TV receiver-or 8 MHz. The letter from Sinclair. of resolution is not that great -175/ 8 -MHz bandwidth specification was con- 52.4 µsec => 3.3 MHz. Actually, that spec is firmed in a conversation with a Sony en- Dear Mr. Mitchell: for horizontal lines, not resolution; hori- gineer involved in the Profeel project. We regret any confusion that you may zontal lines make up vertical resolution, ART KLEIMAN have been caused by the assembly in- and 340-350 is a typical picture. Editor structions for our model ZX81 personal C.C. WHITNEY, computer kit. However, we can assure Miami, FL 000000PS! There are several errors in the schematic (Fig. 1) that appeared with my article "Telephone In -Use Monitor" in the March 1982 issue of Radio -Electronics. First, the values of resistors R1 and R3 should be 2.2 megohms, not kilohms (the values are correct in the parts list). Second, introduces capacitor Cl should have its positive end connected to pin 2 of IC1 and its other c7Vew e,Yllore Verf end to the line joining pin 1 of the IC and the cathode of LED1. The way it is shown, the LED will not light. Slit -N-Wrap® Tool Thank you for allowing me to bring those facts to the attention of your readers. for Wire - CHRISTOPHER M. DUNN

wrapping. An error crept into the theory -of -opera- Battery de- & Manual tion section of the "chug -chug" toy ount Wire Wraps Models scribed in our article entitled "4 Toys for Electronically Available the Holiday Season" in the December 1981 Radio-Electronics. et 3 to 9 Wraps It should have stated that "...the op -amp noise current (bias noise -current), if any, would not be converted to a voltage due Eliminate Hand - P184-7 to the low impedances chosen to eliminate Held Wire End $198.00 hum pickup. Thus, FET-input op -amp 110V A.C. types must be used, because they exhibit 'rat Wrap Start with New 60Hz voltage noise, whereas bipolar -transistor Wire Grip Housing! input op -amps exhibit more current than voltage noise...MOSFET op -amps have the highest input noise -voltages (higher 300 Foot than JFET's), but almost no input bias- current-hence, almost no input fluctua- Wire Spool tion current or 'current noise.' " with Tension Regulator Thank you for printing this correction. to Reduce Wire Breakage DAN & DIANE TALBOT Six Wire Colors available cAdvantan tages: POOR PICTURES Faster and Easier Wrapping I happen to be one of those misfortunate No Stripping Americans who live next to the local No Precutting power company's high-tension, distribu- No Premeasuring tion power-lines. After enjoying another evening of good old American AM -modu- No Loading lated television pictures, including car Daisy Chain Wraps ignitions, arcing insulators, overhead air- Quick Change Bits craft, and the like, I have to ask an important question: Why? View of wire ut Reliable Wraps Meet Why in this fast-moving end of bit being day of elec- wrapped on post. MIL -STD 1130A, par. 5.6 tronics technology are we still strapped to U.S. & Foreign noisy, degraded TV pictures? 11eClJ81ecem ceorrpany Patents The satellite industry has already CORPCR.ITED proven FM television far superior to AM,

and I for one would like to see it a reality. 12460 Gladstone Ave., P.O. Box 4336, Sylmar, CA 91342-0336, phone (213) 365-9661 Price Subject to Change Without Notice. 828108 With all of the new low -power UHF -AM See us at Electro Booth No. 1510 stations to start springing up all over the country, it seems that, as times goes on, CIRCLE 42 ON FREE INFORMATION CARD continued on page 36 32

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www.americanradiohistory.com LETTERS RCA's Newest See and Do continued from page 32 he harder the situation would be to VCR Video Tape Program... change. Let's see some of those "off -the -air Pay -TV" stations start experimenting with "Familiarization and Servicing FM modulation. For those who choose not to subscribe, the distorted, out -of - The VGP170/TGP1500 sync pictures would prove just as un- watchable as those you get from present Convertible VCR System" scrambling techniques. A simple FM-converter/AM-remodulator box could then be provided to subscribers. The only place AM interference could enter would be on the cable from the converter to the TV set. That could be a perfect way to test FM -TV in this country. Stations could forward their results to the FCC and, if successful, we could soon see FM -perfect stations popping up all over. "Bandwidth too broad," you say? Well, how about some form of frequency-corn- panding technique? Come on, all you electronics engineers: Show us what you can do! Remember when FM radio was only a dream on the part of E.H. Armstrong? Just think: People could say, "I subscribed to that new pay -TV station, and the picture is so great that it's worth the $18 a month." GARY N. SMITH, Sinking Spring, PA

Video Tape . . . 80 -Minutes, Full Color AUTOMOBILE IGNITION SUBSTITUTE With respect to the "New Ideas- column Workshop Manual . . . Fully Illustrated in the February 1982 Radio -Electronics, I Step -by -Step Servicing Procedures think that with a little close examination you will find that the author, Stan K. Training Workbook . . . Reinforces Your Stephenson II, knows very little about electronics, still less about gasoline Learning with "Hands -On" Exercises engines, and needs to go back to school for his math. The 2N6384 power darlington transistor Package only $89.95 has a collector-to -base breakdown volt- Complete age of 60 volts. The reason for the capacitor across the coil is to create a flywheel This full -color Technical Training Video Tape (VHS Format) is invaluable effect, causing a reverse emf of up to 450 volts; therefore, a power -transistor with a at the bench when the VCR or for technician training or for use breakdown rating of at least 400 -volts Tuner/Timer is being serviced. Includes visual instruction with audio should be used, then a Zener diode of narration on Tuner/Timer, IR Remote, Cylinder and Capstan Servo about 350 volts should be placed collec- servicing, plus Sound -on -Sound operation and much more. tor -to -base to clamp any spikes exceed- Systems and circuits are referenced to the VCR counter number so ing 350 volts. It is not good practice to use the voltage rating of a capacitor for a proceed to the related subject matter. that technicians can directly clamp, such as the .05/100 that he is using collector -to -emitter. The frequency at which he is running

his oscillator, 1 -kHz, is equivalent to Yes! 15,000 rpm, not 650 rpm. I think that is a RC/1 little too fast for a car engine to idle. Send the number of tapes I have indicated to address below: 1 kHz x 60 = 60,000 sparks per minute. fires 4 times per Enclosed is my check or money order payable to RCA Corp. An eight -cylinder engine revolution. Thus, 60,000 divided by 4 Quantity @ $89.95 Each equals 15,000 rpm. As for the neon lamp, who is going to Total Enclosed Allow 4-6 Weeks Delivery hold a small NE2 neon lamp, with 30,000 volts it, eighth of an inch away THIS IS YOUR SHIPPING LABEL - PLEASE PRINT across one from a pulley, fan, and a bunch of belts NAME turning at 15,000 rpm? In conclusion, it is my hope that any- STREET ADDRESS body who tries that gadget is lucky CITY STATE ZIP enough to have the .05/100-volt capacitor short the first time the coil fires, thereby MAIL TO: RCA Technical Training 1-450 eliminating all of the aforementioned problems. 600 N. Sherman Drive, Indianapolis, IN 46201 8204 -4 -RE L GORDON HENDRIX R -E

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lent graphic examples to acquaint the user with the wide variety of sounds Radio Shack RAD O SHACK MG -1 available. Some of those sounds include musical and sound effects. Model MG -1 Music OVERALL instruments PRICE The manual also includes a section on basic music theory for those with little ,, ( OFEASEE or no music background- 1 INSTRUCTION IVANUAL The 21/2 -octave full -chromatic key - PRICE/ board is used in combination with a wide . VALUE variety of tone -controlling features: a 1 2 3 4 5 6 7 8 914 2:1 sync selector, 3 position octave º Fe cpò selector, square or triangular wave- CIFCLE 101 ON FREE INFORMATION CARD shape selector and even a mixer that will let you mix two tones, a noise source, bell tone, or polyphony (which allows FOR YEARS. THE MOOG SYNTHESIZER HAS Now Radio Shack (One Tandy Cen- you to play chords). been synonomous with modern elec- ter, Ft. Worth, TX 76102) has entered Modulation capabilities include vi- tronic music and rock bands. Early ver- the market with their model MG-1 from brato, tremolo, random, and glide se- sions of that device, however, were Moog. quences. A separate filter permits cutoff very expensive and were regarded as The instruction manual that accom- and peak emphasis, while a contour sec - status symbols for the rock musicians. panies the instrument provides excel- tion adjust rise and fall times. continued on page 42 VIDEO DISCOUN W TEKNIKA WIRELESS COAXIIALSWITCHING FOR VHF/FM AMPLIFIERS REMOTE CONTROL TV VIDEO CASSETTE TV TUNER RECORDERS C Model 7002 $9.95 ea Model AB -370 $6.95 ea All solid state signal amplifier $110.00 ea 3 -position coaxial boosts weak signala For 2 seta Model 6301 push-button switch REMOTE TV Model 7004 $12.95 ea -'CONVERTER COAX AB SWITCHES For up to 4 sets Signal gain 3 dB Wireless Remote Control 40 Channels 4 or more Model AB -27 $2.95 ea DISTRIBUTION AMPLIFIER VHF/UHF FM Imput: 75 ohm. Output: 75 ohm. 139.95. 125.00 e Model CTC5R 25 $29.95. 36 CHANNEL UP Model AB -28 $2.95 ea Model AB -29 $2.95 Designed for TVNCR CONVERTER FOR TV Input: 75 ohm. Input: 75 & 300 ohm. multiple -set installations. & VTR Cable VHF to UHF Output 300 ohm. QUICK CONNECT "F" Model V5736 PLUG & BALUN 1-3 pieces$29.95ea ANTENNA/CABLE TV ModelV 400 $1 .50 ea SWITCH 10 for $12.50 4 pieces & up $24.95 ea QUICK CONNECT Model AB -400 $10.95 ea "F" PLUG RG 59U VIDEO SWITCHER ANTENNA/CABLE TV QUICK CONNECT ModelV 4036 SWITCH $9.95 "F" PLUG Model V 4801 $29.95 ea Model AB -410 ea ModelV 403.75 $2.50.. Flip a switch to watch a program on Switches from cable to antenna 10 for $6.00 any channel, while simultaneously system instantly. Accepts 75 or For 75 ohm cable. recording a program on any cable 300 ohm imputa No wiring necessary. or pay TV channel - or vice versa. Plus, you can use your recorder's programming feature to record W VHF/UHF MATCHING TRANSFORMERS programs while you're away. Model MT -1 $.75 ea VIDEO CONTROL CENTER 10 for $6.00 VHF/UHF 75-300 ohm ModelV 4802 $39.95 ea matching unit Miniature Model MT -2 $1.10ea. COAXIAL SWITCH size completely shielded Provides remote control access of TV GAME SWITCH 10 for $9.00 all your Video, TV or Cable imputs and balanced for reduction Model DCS-A/B $7.95 of direct pick-up. Completely plastic molded to your TV set or Big Screen TV ModelV 450 construction for weather- from one convenient location by $2.95 A versatile product, with a in and out with proofing. merely flipping a switch. 300 ohm range of consumer and Supplied with RCA plug. MATV applications rubber boot

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www.americanradiohistory.com EOUIPMENT AND TRAINING NO OTHER SCHOOL CAN MATCH. NTS HOME TRAINING INVITES YOU TO EXPLORE MICROCOMPUTERS, DIGITAL SYSTEMS AND MORE, WITH STATE-OF-THE-ART EQUIPMEN1 YOU ASSEMBLE AND KEEP Without question, microcomputers are the Send for the full color catalog in the elec- state of the art in electronics. And NTS is the tronics area of your choice-discover a// the only home study school that enables you to advantages of home study with NTS! train for this booming field by working with NTS also offers courses in Auto Mechanics, your own production -model microcomputer. Air Conditioning and Home Appliances. Check We'll explain the principles of trouble- card for more information. shooting and testing your microcomputer and, best of all, we'll show you how to program it to do what you want. 1 You'll use a digital multimeter, a digital logic probe and other sophisticated testing gear to learn how to localize problems and solve them.

We believe that training on production - model equipment, rather than home-made learning devices, makes home study more exciting and rele- vant. That's why you'll find such gear in most of NTS's electronics programs. For instance, to learn Color TV Servicing you'll build and keep the 25 -inch (diagonal) NTS/HEATH digital color TV. In Communications Electronics you'll be able to assemble and keep your own NTS/HEATH 2 -meter FM transceiver, plus test equipment. But no matter which program you choose, NTS's Project Method of instruction helps you quickly to acquire practical know-how.

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NATIONAL NTS Training Programs TECHNICAL Industrial ectonics

TECHNICAL-TRADE TRAINING SINCE 1905 ResIdent and Home -Study Schools 4000 SO. FIGUEROA ST.. LOS ANGELES, CA. 90037 w 1. The NTS/Rockwell AIM 65 tt NATIONAL TECHNICAL SCHOOL.S Microcomputer A single board unit Figueroa Street. 4000 South 20ír i82 with on -board 20 column alphanumeric Los Angeles, California 90037 Deptp printer and 20 character display. A 6502 -based Please rush FREE color catalog on course checked below unit 4K RAM, expandable. 2. The NTS/KIM-1 E Auto Mechanics Microcomputer A single board unit with 6 digit MicroComputers/MicroProcessors Electronics Air Conditioning LED display and on -board 24 key hexadecimal Communications Digital Electronics Home Appliances A based calculator -type keyboard. 6502 E Industrial Technology E Color TV Servicing microcomputer with 1K RAM, expandable. 3. The NTS/HEATH H-89 Microcomputer Name Age features floppy disk storage, "smart" video terminal, two Z80 micro- Address

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www.americanradiohistory.com EQUIPMENT REPORTS Microtek continued from page 37 Bytewriter- i 000000PS! Above the keyboard is a cluster of Matrix Printer If you had trouble following our re- switch controls that are used to "pro- port on Microtek's Bytewriter-1 last gram" the synthesizer. Two waveform t month, there was a good reason. It generators (sawtooth and square wave) seems gremlins played an April -Fool trick on us moved provide the basic sound source: the and around some type when we weren't looking. Here is modulation controls, filters, and mixers how it should have appeared. shape the final sound. The synthesizer has a low-level, high - CIRCLE 102 ON FREE INFORMATION CARD impedance output that is designed to be used with an existing amplifier, handy Microtek Bytewriter-1 has three individual internal connectors for home or "concert" use. In addition a for the three computer systems. It is OVERALL headphone jack permits the unit to be PRICE almost impossible to mix up the con- used in a noisy environment, or without EASE nections if you move the printer from disturbing others. The unit also includes OF USE one computer system to another be- INSTRUCTION a built-in AC power supply. MANUAL cause the required interface cable from Rear -panel jacks provide pitch and PRICE the computer to the printer will attach trigger interface ports for computer con- VALUE only to the appropriate connector. trol. Another rear-panel jack allows you The Bwetrriter-I prints both upper to input an external sound source, such and lower case-without lower-case as a tape recorder. descenders-at 10 characters -per -inch. The lightweight instrument has a pro- 6 lines to the inch. It accepts 95 of the fessional look: basic black vinyl with 96 standard ASCII printable character color accents grouping the controls by THE BYTEWRITER-1 MATRIX PRINTER. codes and three control codes. common function. The "feel" of the by Microtek Inc.. is a 7 x 5 dot-matrix In the ASCII "standard". the char- keys is quite conventional and the spac- printer for the TRS-80. Apple and acters start at decimal code 33 and run ing is standard. Apple 11. and Atari 400/800 com- through decimal 127. Code 127, how- The model MG -I provides an eco- puters that specifically answers the ever, is not really a character: it is the nomical alternative to more expensive need for an inexpensive printer ca- delete function. Some printers, on re- electronic sound generating equipment. pable of accommodating standard letter - ceiving a code 127 from the computer, It sells for $499.95. and is available size sheets and paper rolls. will do nothing. The Bvteu niter -I. how- from Radio Shack outlets. R -E Priced at only $299. the Bvtewriter-/ ever. translates code 127 into an open

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THE TEST EQUIPMENT SPECIALISTS v,sa TOLL FREE HOT LINE 800-223-0474 Prices subject to change without not,ce 54 WEST 45th STREET, NEW YORK, N.Y. 10036 212 ô87-2224

www.americanradiohistory.com Alarm The Burglar Midex 55 alarm system measures A computerized burglar alarm requires no only 4" x 10%" by 7" yet protects you installation and protects your home or like much larger and business. It is the first real alternative to a expensive security thousand dollar or more professional system. systems.

The concept is simple. Provide all electronic EXPANDABLE SYSTEM U.L. APPROVED SYSTEM functions of a professional wired together You can set up the Midex in your own home If you have owned a burglar alarm for more system. Put sensing and control into one in minutes. It looks like a stereo component. than a year, there's a good chance that it has easy -to -use device. Use large scale integration Just plug it into a wall socket, aim and adjust required service. The Midex, however, is of solid state components to achieve lower its protection pattern and connect two wires solid state and built with the same heavy cost and greater reliability. Here are some of to the powerful alarm blast horn SP -30. If duty components in industrial systems. The the exciting features: you wish, you can connect two alarm blast Midex is made by Solfan Systems, Inc., the Invisible Protection. The Midex 55 protects horns. If you connect 2 blast horns, we leader in the production of radar detectors your home using exactly the same technology recommend one outside and one inside. for commercial and industrial security sys- than half a that police radars use to catch speeding cars A test light allows you to easily determine tems. Solfan has made more over and trucks. When you are not at home, the the area of coverage of the protection million industrial radar sensors and A wheel lets you adjust it to 100,000 Midex 55. Will the Midex ever need Midex 55 generates a low energy radar field pattern. thumb needs. service? No product is perfect. If you ever that detects anyone who moves in a desig- your have a call us on our toll free nated area of your house. The protection As an extra security measure, you can con- problem, "help line" at 227-8167. The product pattern is an adjustable tear drop shape with nect one or more panic buttons to the Midex. (800) 1 parts and labor warranty. maximum dimensions of 50 x 20 feet. The panic buttons activate the alarm even has a limited year Loud Alarm. When the system detects an with the radar protection pattern turned off. STANDING BEHIND A PRODUCT But even if you don't use the expansion intruder, it turns on a loud police type The Midex protects more than 100,000 features, the Midex is complete, ready to electronic siren. The sound is loud enough American homes. But the true test of how it protect you, just as it arrives in its well - to cause pain. It is loud enough to drive a performs is in your home or office. That is protected carton. burglar away before he can steal or damage why we provide a one month trial period. your valuables. It is loud enough to alert We give you the opportunity to see how fail your neighbors and, more important, loud safe and easy to operate the Midex system is enough to warn you not to enter your home and how thoroughly it protects you and before the police arrive. your loved ones. Decide after one month Computerized Controls. To turn the system whether or not you want to keep it. If you on, you punch in your personalized 4 digit decide to keep it, you'll own the best. If access code. You now have 30 seconds to not, return your unit for a full and prompt leave your home or office. When you return, refund. There is no risk. you enter and disarm the system with your Purchase the Midex 55 now for $199.95 and access code. You have 30 seconds to do the SP -30 blast horn for $39.95. We recom- that also. mend the purchase of two blast horns. To When the Midex senses an intruder, it remains order, simply send your check to the address silent for 30 seconds. It then sounds the shown below. California residents add 6% alarm until 8 minutes after the burglar leaves. sales tax. Credit card buyers may call our The alarm then shuts off and resets, once toll free number below. There are no postage The adjustable pattern has a range up to again ready to do its job. This shut-off fea- or handling charges. The unit will be sent to 50 feet. ture, not found on many expensive systems, you complete with all instructions. means that your alarm won't go wailing all Midex gives you everything you could pos- NO MORE FALSE ALARMS night long while you're away. sibly expect from a burglar alarm: 1) a Compared with other burglar alarms like Standby Power. Should AC power fail or professional grade system at a very reason- ultrasonic systems, the Midex has almost no a smart burglar cut your AC power lines, able price, 2) toll free telephone assistance, chance of false alarms, since it is not affected the Midex 55 automatically switches to 3) the chance to buy a unit in complete by traffic noise, plane noise, air conditioner FAIL-SAFE operation using a built-in confidence, knowing that you may return turbulence, telephones or strong outside rechargeable battery pack. You are protected it if it's not exactly what you want. You winds. Only the motion of the burglar no matter what. can't lose. walking through the radar field can set it off. Computer technology has produced the COMPARED AGAINST OTHERS ultimate security system. Order your Midex The Midex compares with much more expen- 55 without obligation today. sive professionally installed systems. Yet it costs no more than do-it-yourself alarms purchased at retail. In a recent article, a leading consumer magazine rated the Midex tops in space protection, alarm siren power and immunity from false alarms. Don't be confused. There is no system under $1000 that provides you with the same protection. midex 665 Clyde Avenue Mountain View, CA 94043 The powerful blast horn has a 120d8 output (415) 964-7020 in Calif. and makes a sound so loud it causes pain. (800) 227-8167 CIRCLE 23 ON FREE INFORMATION CARD

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box of the type used on questionnaires. mainder are "wrapped around" on the code. A line feed is automatically If you were printing something where next line. accomplished as a result of the. carriage you might want to check off each step When the printer receives the SO return. If just a line feed is desired, it is with a pencil or pen, the open box code, all data that follows is printed out necessary to send a CR code to the would be an asset. in "bold" double-width characters. printer. While that provides a line The Bvteu rnter-I responds to three Reception of the SI code cancels the feed, it also moves the printhead to the ASCII control codes. Those are: CR "bold" characters and all printing that beginning of the next line; that makes it (carriage return), SO (shift out), and SI follows the SI code is normal width. somewhat difficult, if not impossible, (shift in). CR also provides an auto- The SO and SI codes can be inter- to line up columns. matic linefeed. When the printer re- mixed at will in the same line, per- Unlike earlier "budget" printers that ceives the CR code, all data stored in mitting individual characters, words, used rolls of narrow, adding -machine the print buffer is printed and the paper and phrases to be printed "bold." type paper that permitted lines of per- is advanced one line. If more than 80 The bold characters do not cancel at haps 16 or 30 characters, or that used a characters have been received and the end of a line, but will continue until somewhat difficult to obtain and ex- stored in the printer's buffer before the the SI code is received. pensive heat -sensitive or electrostatic CR is sent by the computer, the first 80 Like some other printers, the Byte - paper, the By'tew ricer -I uses standard are printed on one line and the re- writer -1 ignores the Line -Feed (LF) sheets-letter or legal size-or standard paper rolls up to 811 -inches wide. The paper feed is friction only; there are no IS PROUD TO INTRODUCE the tractor or pin -feed devices. Single ADVANCE sheets are inserted from the rear. Per- KEITH LEY Line of High Quality Digital Multimeters manent brackets and a removable Featuring The New 130 Hand -Held DMM spindle are provided for paper rolls. The bracket supports a standard 5 -inch diameter teletype paper roll off the table-the user is not limited to one of the new mini -size rolls of approximately 3 -inch diameter, which happen to cost more than the standard roll. The characters are printed by a 7 - wire printhead that plugs into a socket and is user -replaceable by simply loosening two screws and unplugging the connecting cable. Unlike most other printheads that are connected to their electronics by a flexible ribbon cable that "rolls" along with the print - head, the Bvtemriter-I uses discrete, highly flexible wires to connect the printhead to the circuit. The wires flop and twist considerably as the printhead travels. While it does not appear to the eye that the twisting wires would have the life expectancy of "rolling ribbon", there is no previous experience on which to make a judgment as to life expectancy of the wires. The printhead is driven by a grooved spindle, rather than a drive belt. Again, Rugged DMMs from Keithley - all feature large, bright that is an arrangement we have not LCD display, easy -to -use rotary switches, externally accessible seen used in a matrix printer before; battery and fuse, l0A current range, diode test capability, low but it does work. Again, we have no battery indicator, cushioned components. idea what the life expectancy or reliability might be; but after several Model 131. Similar Model 130. Our Model 135. First weeks of quite severe useage-likely to Model 130, with most popular model, 4' -digit DMM with more done by increased the price/perfor- hand-held than the average hobbyist-we have had not a single instance accuracy $139 mance champ . Convenience. 125 $235 of difficulty with any part of the printer's ACCURACY SENSITIVITY electrical or mechanical assembly. The MODEL DCV DCA ACV ACA SI DCV DCA ACV ACA SI printhead's bi-directional drive is the "full line" system commonly 130 0.5% 1% 1% 2% 0.5% 100µV 1µA 100µV 1µA 100mn found on many lower -cost printers; it is 131 0.25% 0.75% 1% 2% 0.2% 1000V 1µA 100µV 1µA 100mO2 not logic -seeking. That is, the head 135 0.05% 0.5% 1% 1.5% 0.2% 100µV 10µA 100µV 1µA 100m4 sweeps from full left to full right, even Case $10.00 Shipping $3.00 if it prints just a single letter on the left side. It then sweeps back from full THE TEST EQUIPMENT SPECIALISTS right to full left regardless how much it TOLL FREE HOT LINE has to print. The printer speed is 80 characters -per -second (per line). 60 800-223-0474 lines -per -minute. \5a WEST 45th STREET NEW YORK. N Y 10036 212.687 2224E There is no impression adjustment 44

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It's not the bible, but a lot of service technicians swear by it.

Behold! The Sylvania ECG transistors and linear [Cs by and usually exceed those of the Master Replacement Guide, tl application_ You will find clear, original parts and that they've most comprehensive publication concise descriptions and illustra- been tested using stringent proof its kind used by the industry. tions on each type from diodes cedures established by the U.S. Inside you wiL find more than to IC's with specifications, appli- Military. 170,000 industry part numbers cations and package dimensions. To find out more, seek your cross referenced to over 2,500 What's more, you also have nearest authorized Philips ECG ECG- numbers, including most Philips ECG technical resources distributor. of the hard -to -find foreign parts ready to help you with any ques- If you are not already a that are plaguing more and more tions you might have regarding believer, one look at our catalog repairmen every day. particular situations or applica- should convert you. If the part number is illegible, tions; and as always, all ECG there are also easy to use com- parts you will receive come with prehensive selection tables to the knowledge that they've met PhiipsECG help you identify and replace specifications which are equal to A North American Philips Company "For your nearest ECG distr&,utor, please call 1-800-225-8326.: in Mass., call 1-800-342-8736."

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www.americanradiohistory.com SIMPLE SIMON ELECTRONIC KITS, Inc. for the printhead; it is set at the factory INTRODUCING 7 + 11 SWD PARTS KITS and will print up to the original and three copies. Our experience showed a 0 MITSUMIde somewhat irregular impression impact - OUR VARACTOR ._ density where a substantial part of the _ character was reproduced by a string AMATEUR ETV UHF TUNER 1 MDS - - Model UES-A56F of dots, such as the small letter "e", or the parenthesis symbols [ (,) ]. While 32 ELEMENT YAGI ANTENNA $34.95 . the "top" (original) copy was legible, Freq. Range UHF470 - 889MHz Antenna Input 75 ohms the copies-particularly the third- Channels 14-83 Output Charnel 3 were somewhat difficult to read. Also, , UZZZZZIp11`»»»»»"" alr PART bear in mind that "copy does not mean 11»>»ï* No DESCRIPTION PRICE NO NOT A KIT 1 el -SW Veractar UHF Tuner, Model UES-A56F $34.95 carbon. Using sheets of letter -size ',9: 2 CB1-SW Printed Circuit Board, Pre -Drilled 16.95 paper, the original and two NCR (No 1.9-2.5 GHz 3 TP7-SW P.C.B. Potentiometers, 1-20K, 1-1K, end 5-10K ohms, 7 -pieces 5 95 Carbon Required) copies just barely 4 FR35-SW Resistor Kit, 'A Watt. 5% Carbon Film, 32 -pieces... 4.95 slipped through. The original and three 381/2" LENGTH 5 PT1-SW Power Transformer, PRI-117VAC, SEC-24VAC, 250me 6 95 NCR's required considerable care to 23 dB AVE RAGE GAIN 6 PP2-SW Panel Mount Potentiometers and Knobs, t-1KBT load. Unless a Mylar carbon film was and 1-5KAT w/Switch 5 95

7 SS14-SW 4-pcs, Regulators 2-pcs used it was somewhat difficult to make DIE CAST WATERPROOF HOUSING He atUriDpeces 2995 "carbon copies" using single sheets FOR 8 CE9-SW Electrolytic Capacitor Kit, 9 -pieces 595 ELECTRONIC CIRCUITRY 9 CC33-SW Ceramic Disk Capacitor Kit, 50 W.V., 33 -pieces.... 7.95 because it was difficult to load single D CT -SW 56 Ceramic6-f Trimmer Capacitor Kit, sheets interspersed with ordinary COMMERCIAL GRADE 5-8Sp5p1d. 6 -pieces 5 95 11 L4-SW Coil Kit, 18mhs 2-pieces..22µhs 1 -piece (prewound carbon paper. Paper rolls that con- and Ferrite TumidCore sisted of factory interleaved original, INCLUDES MOUNTING HARDWARE inducwith 1 T37-1 ire 500 12 ICS -SW I.C. Sockets, Tin inlay, 8 -pin 5 -pieces carbon and "second sheet" (copy) MODEL NO. ONLY and 14 -pm 2 -pieces 195 13 SR -SW Speaker, 448" Oval and Prepunched were more convenient because they MAE -1 Y 19.95 Wood Enclosure 14.95 fed through smoothly and without any 14 MISC-SW Misc. Parts Kit Includes Hardware, (8/32, 8/32

Nuts, 5 , Hookup Wire, Ant. Terms, SPOT bother. Actually, roll paper proves the Ant. Switch,tch, Fuse, Fussholder, etc 9 95 most convenient to use; and it's cer- VTR ACCESSORIES When Ordering All Items, I1 thru 14), Total Price 139.95 tainly inexpensive if you purchase the UHF ANTENNAS and ACCESSORIES SIMPLE SIMON VIDEO ordinary teletype -paper grade. 7."ZZX One nice feature is that the paper

STABILIZER can be rolled backwards or forwards t VHF-UHF WIDEBAND 1,2t-= whether the power is on or off. Typical ANTENNA AMPLIFIER matrix printers, line is low, V ANTENN of the print Model MODEL ALL -1 out of sight. If you print one line you 50 MHz - 900 MHz roll the paper forward VS -125 X12 dB GAIN ± 0.5dB can to check copy and then roll it back for additional Pore A Revolutionary New printing; it's not necessary to turn off Simple Simon Video Stabilizer, Model VS -125, - One Stage HYBRID the printer to roll the paper backwards. eliminates the vertical roll and jitter from "copy IC Broadband Amplifier The ribbon is supplied in a cartridge guard" video tapes when playing through large This unit is not available anywhere else in the world. One unit screen projectors or on another VTR. Simple to serves many purposes and is available in Kit or Assembled that spans almost the full length of the use, just adjust the lock control for a stable form. Ideal for outdoor or indoor use. Input-output impedance printer. It simply drops into place; s 75 ohms. Amplifier includes picture.Once the control is set, the tape will play separate co -ax feed power imbled in 25 minutes. No coils, capacitors there is no threading or positioning. It all the waythrough without further adjustments. 9 1 etc.supply.to tunEaselyorassej adust. is one of the easiest ribbons to install, Includes 12V power supply. ALL -1 Complete Kit with power supply $24.95 even for someone who is all thumbs. ALL -1 Wired and Tested with power supply $34.95 VS-125 Video Stabilizer wired $54.95 Replacements are priced at $7.95. The printer is rather small. Without Our New STVA 14.5 dB GAIN, SIMPLE SIMON VIDEO the paper-roll adapter, it measures 15 14 ELEMENTANTENNACORNER REFLECTOR SWITCHING BOX x 91/4 x 3 -inches. (You must allow YAGI some room at the rear for loading . Model VSB-300 il-. paper.) The power switch is located at the left rear outside the paper path. The _:.-, The interface cable comes out the right __ - Affordable - \\` STVA-3 YagiAntea,m rear, also outside the paper path. ,,.-'^' 14.5 dB, 75 ohm, Chan. 60-68 ... 516.95 (Even some of the best of other printers -vesrso Video S1VA-4 YagiAntenna. SIMON SIMPLE 14.5 dB, 75 ohm, Chan. 44-52... $16.95 are known to get their cables tangled Control Center! up with the paper because the cables Excellent in isolation and no loss routing system. are right in the feed path.) On the top Simple Simons VSB-300 Video Switching Box STVA-1 YagiAnterna, 11.5dB, 75ohn,Chan. 42-54....$9.95 right is a recessed, toothed knob for enables you to bring a variety of video components manual paper positioning. together for easy viewing/dubbing. Also you gain While the Bytewriter-I has some the ability to record one channel while viewing RG -59/U 75 ohn Low Loss Coax Cable $ .12 p/h another. Unit includes two F -type quick connector F-59 Coaxial Connectors, ea 39 obvious limitations, such as variable ended cables MT-1 Special UHF 75-300 ohm Transfoer.Transformer. ea 1 45 impact density and lack of direct line ALL -1 HYBRID IC Wldeband VHF -UHF -FM Antenna Amplifier Kt . 24 95

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www.americanradiohistory.com VID BE

HOME SATELLITE -TV RECEPTION. ONCE A dream, is now a reality. Thousands of enthusiasts have installed their own 'backyard" earth stations and the simple, inexpensive receiver that will ,:be described here will z.11ow you to do the same. To understard how satellite TV works, let's look at why and how it developed. In the early days of TV, transmissions the complete plans for a -TV receiver to go ere strictly local, using the standard Here are satellite HF -frequencies. Later, as networks with the 8 -Ball antenna we presented in 1981. Add an LNA ere formed, there came a need for na- for a complete satellite -TV earth station. ionwide video -distribution systems. oaxial-cable lines and multiple copies (HBO) and Cinemax, a 24 -hour news The satellite link of films or kinescopes (films taken from channel. daily live coverage of the We said earlier that a satellite -com- a video monitor) were used initially, House of Representatives, a channel munications link is made up of three but they were costly and were gradually devoted entirely to sports, "supersta- parts: the ground transmitting -station, replaced by microwave -relay links. tions" WOR-TV in New York and the satellite, and the ground receiving - By 1980. satellite communications WGN-TV in Chicago, and many others. station. They are shown in Fig. 3. Let's had progressed far enough to allow the And, if all of that programming isn't first study the ground sending -station, use of a single satellite as a relay point, enough, there are plenty of other satel- or uplink transmitter. broadcasting to TVRO (TV Receive - lites to choose from. Only) terminals across the U.S. Al- though TVRO terminals were expensive, the system was adopted quickly because its overall cost was less than that of a ground -link system. Communications satellites have geosynchronous orbits. A geosynchronous (or geostationary) orbit is one in which the satellite orbits directly above the equator and has an orbital velocity that precisely matches that of Earth's rotation. An observer on Earth sees the satellite as a stationary point in the sky (see Fig. 1). A satellite -communications link has three points: the signal source on the ground, the satellite relay in orbit, and any number of ground -based TVRO terminals. We will examine each of those three points in a moment, but first let's see what type of programming the satellites carry. Presently, as shown in Fig. 2, there are about a dozen U.S. and Canadian satellites within view from this country, with many more due to be launched in the near future. Each satellite carries 12 or 24 transponders (receiver/transmitters)-each one using a different frequency-pair-with programming that includes movies, sports, news, and almost anything else imaginable. The domestic satellites can provide up to 228 separate TV channels, or over 200,000 telephone voice -channels, simultaneously. The most popular satellite is RCA's Satcom FI (located at 135° west latitude) which is used by cable - 1'V companies to relay their programs. As an example of the diverse programming it carries, services available on Satcom FI include: Home Box Office

www.americanradiohistory.com The job of the uplink transmitter is to very accurately to insure that it reaches 40 MHz wide. send a frequency -modulated video sig- the "bird" with maximum strength. A That's fine for a 12 -transponder satel- nal (as opposed to the amplitude -modu- signal of at least 500 watts is fed to a lite, but how do you fit 24 channels in lated video signals used in broadcasting) parabolic -dish antenna. That antenna the same space? A combination of two and an FM -audio signal to the satellite provides gain by reflecting energy that systems is used. First, the channels are using a carrier in the 5.9-6.4 -GHz would normally be radiated away from staggered so that the center of one range. Since the satellite is over 22,000 the satellite and focusing it into a con- channel is at the upper and lower edges miles away, the signal must be aimed centrated beam toward it. of the adjacent ones, as shown in Fig. An uplink station can beam up more 4. The channels overlap, though, and than one video channel at a time by normally would interfere with one an- using special signal -combiners. The other. To avoid that interference, the 1 REVOLUTION/DAY most recent development in uplinks is signals are cross -polarized. At micro- GEOSYNCHRONOUS SATELLITE mobile transmitters; an antenna and wave frequencies such as those used transmitter mounted on a trailer and in for satellite transmissions, signals po- a van are transported from place to larized at right angles to one another place for on -location broadcasting. are isolated by about 30 dB. Odd -num- That allows live video -broadcasts to be bered channels are vertically polarized; beamed from and to virtually anywhere even -numbered ones horizontally po- in the world. larized. In that way, the channel being The next part of the communications received is 30 -dB stronger than its op- link is the satellite itself. It uses a positely polarized neighbors-more parabolic dish to receive the 6-GHz up- than enough to mask the undesired link signal, and then retransmits it back signals. to Earth on a lower 3.7 -4.2 -GHz carrier. The biggest problem with the down- Using two separate frequencies allows link signal transmitted by the satellite is it is weak. 1 ORBIT/DAY simultaneous reception and transmis- that quite Since the satellite sion. Both the uplink and the downlink is expected to perform without any (satellite -to -earth signal) paths have a maintenance during its expected life, it FIG. 1-THE ORBITAL VELOCITY of a geosynchronous satellite matches the rotational speed 500 -MHz wide frequency -range (5.9-6.4 must be solar powered. Even with the of Earth exactly, making it appear to be sta- GHz and 3.7-4.2 GHz) which means most efficient solar panels, it can only tionary in the sky. that there is room for 12 channels, each produce about 5 watts of output power

IV -A F6 per transponder. That means that after IV-A F3 INTELSAT the signal travels 22,000 miles to Earth, IV F5 INDIAN losing 1% dB of its initial strength CLUSTER (dropping to almost 5 x 10-20 watts), the ground receiving -station is not left with much to work with. 100° 90° 80° 70° 120° 110° The first component a TVRO EAST of ter- 140° 130° minal is a large parabolic or spherical - 150° PACIFIC X160° reflector antenna, typically 10 or 12 feet IV F8 170° in diameter. (Construction of a spherical 180° 170° antenna, the "8 -Ball," was described 160° in the August, September, and October 150° 1981 issues of Radio -Electronics.) The 120° so° /13tr 110° 100° antenna gathers all the signal that falls WEST on its surface area and reflects it to its SATCOM LONGITUDE IV -A F2 focal point where an LNA (Low Noise F1 ANIK COMSTAR 8 IV -A F4 Amplifier) is positioned. Using cascaded Di INTELSAT ATLANTIC WESTARSATCOM CONSTAR GaAsFET and bipolar transistors, the ANIK ANIK COTARMS WESTAR 3 CLUSTER 2 3 LNA amplifies the 4-GHz signal by F2 3 1 about 40 dB while adding only one or W ESTA R two dB of noise. It is important to intro- 1 duce as little noise at this stage as pos- FIG. 2-U.S. AND CANADIAN communications satellites lie between 80 and 140 west longitude. sible, since any that does creep in will be carried and amplified through the rest of the system. Once the signal leaves the LNA, it 00 travels down a heavy coaxial cable to the receiver, the heart of the TVRO terminal. -V e Receivers The receiver-the final part of the satellite -communications link-takes the 22,300 MILES 4 -GHz RF signal from the LNA and transforms it into standard composite - TVRO video and audio. Receivers can be de- RECEIVER UPLINK signed in a variety of ways and a dis- TRANSMITTER cussion of some of the features desirable in a receiver will demonstrate what a FIG. 3-THE UPLINK TRANSMITTER sends a 6 -GHz signal up to the satellite, which retransmits the quality unit should be capable of doing. video and audio information back to Earth on a frequency in the 4 -GHz band. A receiver should be fully frequency-

www.americanradiohistory.com agile; that is, it should be able to be How it works signals produces the sum and difference tuned over the entire 3.5 -4.5 -GHz Figure 5 shows a block diagram of of the two. The R2B mixes signals in band. That will allow 24 -channel use, the R2B receiver. Figure 6 is a schematic the 3.7 -4.2 -GHz range with 2.6 -3.1 - as well as the reception of transmis- of the mixer section of the receiver, and GHz signals from the local oscillator to sions from foreign satellites. Its sound- Fig. 7 is an overall schematic of the produce a difference frequency of 1100 subcarrier demodulator should be unit. MHz.) Small wire loops, L12 and L13, tunable over the full range of 5.5-7.5 The input to the receiver is the act as chokes and couple the 1100 -MHz MHz. The various transponders trans- amplified 4 -GHz signal from the LNA. signal -bearing intermediate frequency mit their audio information on sub - Circuits to handle signals in that fre- to the main receiver -board. carrier frequencies located. within that quency range are both critical and ex- The tunable local oscillator, IC10, is range and the receiver should, of pensive, so the 4 -GHz signal is im- a thin-film MIC (Microwave Integrated course, be able to demodulate any of mediately converted down to an 1100 - Circuit). It is difficult to build voltage - them. MHz intermediate frequency (IF) by tuned oscillators from discrete compo- Another important feature to con- the first -mixer stage of the receiver. nents that will operate reliably at micro- sider is dual conversion, where the in- wave frequencies and that IC does the coming signal is converted to a lower First mixer job nicely. frequency in two steps rather than one. This stage is probably the most exotic The advantage of dual -conversion re- part of the R2B receiver. Although it is 1100 -MHz first IF ceivers is that they do not interfere with simple in design, it is quite complex in The first -IF stage, which follows the one another, allowing multiple units to the way it works. first mixer, uses three stripline transis- be operated in the same vicinity. A A double -balanced design is used for tors, Q 1-Q3, to provide 5-10 dB of gain single -conversion receiver, on the other impedance matching and to provide at 1100 MHz. The primary function of hand, can cause (and suffer from) inter- good local-oscillator rejection char- that stage, though, is not to provide ference problems because of an oscilla- acteristics. The input signal from the gain, but to provide bandpass filtering. tor that would necessarily be operating LNA igsplit in phase by a quarter -wave Properly tuned, the first -IF stage gives within the 4-GHz band. A quality re- transmission -line balun, L11, and excellent image -rejection as well as ceiver should also incorporate an AFC coupled to the other side of the PC limiting the total power (both signal and (Automatic Frequency Control) circuit, board through capacitors C72 and C73, noise) of the signal for the second -IF and, of course, be easy to assemble and which are actually formed by the PC- stage. align. The R2B receiver presented here board material-the board itself acting Each stage is biased for class -A op- uses a dual -conversion design and pro- as a dielectric between the two tinned - eration at about 5 mA of collector -cur- vides the features just described. copper surfaces. The phase -split signal rent. Small (5 pF) capacitors couple the is then fed to a diode quad made up of inputs and outputs of the stages. Minia- 1 3 5 7 9 11 13 15 17 19 21 23 D10 -D13. ture resonators are formed by piston I I 000 1 1 I 1 1 1 1 1 1 1

I I 1 1 I I i I I 1 1 I EVEN 1 Similarly, the signal from the local capacitors. Proper impedance -matching 2 4 8 10 12 14 16 18 20 22 24 8 oscillator is split using another transis obtained by the placement of the 3700 MHz 4200 MHz mission -line balun, L10, and then fed to coupling capacitors on the lead -straps FIG. 4-HOW TO FIT 24 channels in a 12 -chan- the quad. The local -oscillator signal of the piston trimmers. Carefully con- nel bandwidth. Adjacent channels are over- switches the diode quad on and off, trolled spacing of the resonator sections lapped, and odd -numbered channels vertically polarized; even -numbered ones horizontally thus producing the mixer products. (In makes possible a composite, double - polarized. superhetrodyne receivers, mixing two tuned filter assembly. The 1100 MHz IF -stage is made up of two such assemblies; each one is isolated by a buf- FIRST SECOND VIDEO FIRST SECOND VIDEO OUT IF DEMOD PROCESSOR fer/gain stage. MIXER IF MIXER 4 -GHz INPUT 1100 70 PLL Second oscillator and mixer (FROM MHz INA) MHz The next stage encountered is the SOUND AUDIO OUT second mixer, which heterodynes the FIRST 1170 -MHz DEMOD ()LOCAL SECOND 1100 -MHz signal with an 1170 -MHz LOCAL OSCILLATOR one, giving an output at 70 MHz. Since OSCILLATOR the R2B receiver has an excellent AFC TUNING AFC range (greater than 20 MHz), a simple, fundamental -frequency, single -transis- FIG. 5-BLOCK DIAGRAM of R2B satellite -TV receiver. Function of each block is discussed in text. tor (Q6) oscillator can be used to make a base -tuned 1170 -MHz oscillator. Its output is buffered by Q5 before driving VTUNE L11' C72' the second mixer, ICI. Once again, the J10 piston capacitor/resonator arrangement is used. To provide a little more gain at the high end, resistor R51's lead in- +15v ductance (that resistor's lead inductance is represented as L7 in the schematic) is used for peaking. Transistor Q5 provides a signal having a level of about +7 dBm to mixer IC l's local -oscillator port; that level insures low conversion -loss as well as keeping TO D10-013: P5827. 'SEE TEXT MAIN the generation of spurious signals to a BOARD minimum. The mixer's output is filtered (THROUGH C11 through a pi -network to provide a clean FIG. 6-FIRST-MIXER stage uses a thin-film MIC (Microwave Integrated Circuit), IC10, for a stable 70 -MHz signal for processing by the tunable local -oscillator. See text for explanation of L10-L13, and C72 and C73. second -IF stage.

www.americanradiohistory.com C16 +12V 2,3,4,5, `'001 -7 NEC5121 1 +18v 6,8,9,10 7 IC2 ..L 62 C2 1 C7 1K R4 .001 1`.001 11 T 1K - R1 47K C4 C5 C9 1C10 a L1 10pF 10pF 1E. 10pF ICI -1( 10pF R5 .15µH C3 y 1 C6 C8 C11 SBL1X C1 47K 1 5pF = _ _ - 5pF 5pF _ _ = 5pF C15 .-.- MIXER 18pF 5pF BOARD +18V 01 IC8 C14 NECO2136 CHANNEL LM334 5pF T ._,v Q2 +12V Q3 CAL. R 1 C53 NECO2136 NECO2136 1 10/16V i(2D 1 R37 5052 I R36 C20 +12V R35 C17 r- 10K R11 001 = 10K 1 TUNING i.001 L 751 R10 33052 R47 = R7 C19 12052 10K 5K 10K 5pF C18 1(----- 10pF C21 2N4123 R 38 5pF 05 47052 R8 _ = 10K Q6 NECO2136 = NECO2136 +12V TP1 R33 10K +12V

+18V TP2 1, +5V Q4 13, C37 y' L2 C24 C25 L4 C28 C29 NEC5121 +5V 1 C36 R18 16 .01 TR19 2.5µH 30pF 15pF 2.5µH 15pF 30pF = 1K g 1/2 2.01 _I_10K ,. , , " MC10231 = 119 I3 0 8 2 L6 ' 6 R12 i 2N4123 - 2,3,4 Clz ÿ czE C26 C27E 2.5µH 14 5,6 7 C34 IC5 56pF 75pF T75pFL5 C30 }.C31 R17 T7SPF 12 5µH 2.5µH75pF 156pF = 8,9 01 ,K N E 564 = R20 1 1K 2 15 R16 7 12 1 4r0R13 47052 1 R15 C35 C38 C39 R50 40pF 470521K IC4-b .01 15pF 15K BIAS 4 = --iF R22 V1^ 6.BK +12V R14, 47052 1/2 MC10231 4.5,8,9,10,11,12 R48, 5K +12V R49 AUDIO C33 +12V 07 C47 3.3K 09 .01 150pF 2N4123 2N4123 )1 1M +12V C54 L9 C49 100pF 1c68J1_ C69 tl R25 L8 3.9pH 1 _ .001 10/16V = 12052 3.9µH Q8 all +5V R41 R23 2N4123 2194123 2K C55 R28 100pF C46 C48 1K +12V 05 C45 Ilk2 R27 T150pF 470pF 119914 1K C61 D6 C67 1K .001 MV2209 30pF 1R R29 C63 10K 12 001

R4 C50 R30 C51 R32 10 47/16V 10K 33052 +15V 16V C58 C59 R52 J4 I.01 18K R43 VIDEO +5V 10K J3 - OUT = I LNA POWER 1/2 1M358 C66 OUT 5 10/16V J2 7 C64 AUDIO OUT 'SEE TEXT T.01 R44 47052 1 C65) = 10/16V

FIG. 7-RECEIVER uses two PLL's (Phase -Locked Loops), IC5 and IC7, to demodulate FM video and stable and offer repeatable results. audio signals. Because those IC's can operate only up to about 50 MHz, IC4-a divides the 70 -MHz second -IF frequency by two, generating a 35-MHz signal that they can handle. Demodulator

Second -IF stage The bandpass-filter section of the After leaving the second -IF stage, The second -IF (or low IF) stage is re- second -IF stage is located between the the signal is at a low enough frequency sponsible for most of the selectivity two gain -block modules and is made up to be demodulated. The demodulator is and gain of the receiver. Prepackaged of a series of cascaded low-pass and designed to extract as much video and gain -block modules, IC2 and IC3, pro- high-pass networks. The 5 -pole filter audio information as possible from the vide about 60 dB of gain, and simplify has input and output impedances of 75 weak satellite -signal. the design and construction of the wide - ohms. Two test points, TP1 and TP2, The design uses a simple PLL (Phase - band (25 MHz) IF amplifier. The are provided for use in sweep -align- Locked Loop), but in a rather unusual second -IF stage sets the noise band- ment of the filter. Molded -plastic, slug - manner. Most PLL IC's have a difficult width of the receiver and is optimized tuned inductors are used as tuning ele- time tracking wide swings-especially for low -threshold performance. ments because they are temperature - at 70 MHz-and the satellite signal is

www.americanradiohistory.com PAR ES LIST

All resistors 1/4 -watt, 5% unless otherwise C42 -C44, C52, C53, C65, C66, C69 -C71- L11-1 inch length .141 -inch diameter specified 10 µF, 25 volts, electrolytic Teflon coaxial hardline (see next R1, R3, R5-47,000 ohms C45, C54, C55-100 pF, ceramic disc part) R2, R4, R6, R9, R12, R17, R20, R24, R27, C46, C47-150 pF, ceramic disc L12, L13 -single loop 28 -gauge enameled R28, R31, R39, R40, R46, R50-1000 C48-470 pF, ceramic disc wire ohms C49-.1 µF, Mylar F1 -3/6-amp slow -blow fuse R7, R8, R10, R19, R29, R30, R33 -R36, C50-47 µF, 16 volts, electrolytic J1 -RCA phono jack, panel -mount R41 -R43, R45-10,000 ohms C51-220 µF, 16 volts, electrolytic J2 -J4 -RCA phono jack, PC -mount R11, R32-330 ohms C72, C73-see text J5 -2 -pin molex plug, PC -mount R13-1000 ohms, trimmer potentiometer, J10-RG58U type "N," female PC -mount Semiconductors JU1-28-gauge wire with 1 -inch insulating R14 -R16, R38, R44-470 ohms IC1-SBL-1 X, 1 -GHz double -balanced sleeving R18-15,000 ohms mixer JU2-Berg jumper clip (for TP1) R21-1000 ohms, 1 watt IC2, IC3-MC5121 broadband amplifier TP1-3-pin Berg mini jack, PC -mount R22-6800 ohms (NEC or other) TP2-2-pin Berg mini jack, PC -mount R23, R26-2000 ohms IC4-MC10231 dual flip-flop S1-DPDT push -on, push -off, PC -mount

R25, R51-120 ohms IC5, IC7-NE564 phase -locked loop T1-18 volts, 1 amp R37-50 ohms, trimmer potentiometer, IC6-LM358 dual op -amp Miscellaneous: PC boards (Mixer board PC -mount IC8-LM334 constant -current source to be made from .062 -inch FR -4 material R47, R48-5000 ohms, potentiometer, IC9-not used with 2/2 -ounce copper and tin -lead linear taper IC10-V815 voltage-controlled oscillator plating not to exceed .0015 -inches in R49-3300 ohms (Watkins -Johnson or other) thickness. Dielectric constant must be R52-18,000 ohms IC11-7815 15 -volt positive regulator 4.83 +.15.), IC sockets, TO -220 heat IC12-7812 12 -volt positive regulator sink, wire, 28 -gauge sheet metal, enclo- Capacitors IC13-7805 5 -volt positive regulator sures, knobs, line cord, fuseholder, C1-18 pF, ceramic disc Q1-03, 05, 06-02136 microwave transis- hardware, etc. C2, C7, C12, C17, C20, C59, C60 -C63, tor INEC-do not substitute!) The following are available from Ramsey C68-.001 µF, ceramic disc Q4, 07-012-2N4123 NPN transistor or Electronics, 2575 Baird Rd., Penfield, NY C3, C6, C8, C11, C13 -C15, C19, C21-5 pF, equivalent 14526: Complete Sat-tec R2B satellite -TV ceramic disc LED1-Jumbo red LED receiver kit with pre -aligned 70 -MHz IF C4, C5, C9, C10, C18-10 pF, piston -type D1 -D4 -1N4004, 1 amp, 400 PIV and 1170 -MHz oscillator sections, trimmer (Stettner 120 -05 -do not sub- D5-1N914 $495.00; completely wired and tested Sat- stitute!) D6-MV2209 20-80 pF varactor diode tec R2B satellite -TV receiver, $749.95; C16, C32 -C37, C56-058, C64-.01 µ F, D7-2N4123 or 2N2222, modified (see text) RM3 RF modulator, $69.95; Watkins - ceramic disc L1-.33 µH choke Johnson V815 oscillator IC (IC10), C22, C31-56 pF, ceramic disc L2 -L6-2.5 µH 41/2 -turn variable slug - $125.00; Avantek 120°K, 50 -dB gain LNA, C23, C26, C27, C30-75 pF, ceramic disc tuned inductor with shield can (Coil - $595.00. C24, C29, C67-30 pF, ceramic disc craft 104-1 1/2T-3/8J-POS3 or equivalent) The above prices include shipping and C25, C28, C38-15 pF, ceramic disc L7 -see text insurance charges to points in the U.S. C39-4-40 pF, trimmer L8, L9-3.9 µH choke and Canada. Overseas orders please add C40 -not used L10-1 -inch length Teflon coaxial cable 15% to cover shipping. MC and Visa ac- C41-2200 µF, 25 volts, electrolytic (see next part) cepted.

wideband. the IC5, has a +18v Since PLL, R21 typical maximum working frequency of 1K OrJ/OF>0 only 50 MHz, a way has to be found around that limitation for 70 -MHz operation. 91 The solution is to use an ECL (Emit- ter -Coupled Logic) divider to divide the 01 03 frequency of the input signal by two. PL1 IC11 +15V That is done by IC4, a high-speed dual 7815 +I flip-flop. One half of that IC (IC4-a) is C42 D2 04 + C41 T10/25V used as a divider, and the other half 2200/ 1 (IC4-b) as a bias source. Pins 14 and 15 125V of the IC are complementary logic -level IC13 +5V outputs. Bias pot R13 is across those Ti 7605 outputs and can be adjusted to provide 18V, lA IC12 7812 C any voltage between the logic -high and = C43 + C44 logic -low levels. When correctly ad- 1C 10/25V T10/25V 117 ,{ T justed, it biases the input to the flip-flop VAC at a level that makes the 70-MHz signal F1 J1 3/8A fi cause the flip-flop to toggle, providing a 01- 134: 1N4004 35 -MHz output. Since both the bias source and the flip-flop are on the same FIG. 8 -POWER SUPPLY provides unregulated 1 8 -volts DC, and regulated 5, 12, and 15 -volts DC for chip, the bias source is temperature receiver. Transformer is physically isolated from receiver to avoid dritt due to component heating. compensated. The 35 -MHz output from IC4-a can frequency of 35 MHz (determined by Video processor be tracked easily by the PLL. The only C38 and C39) is built around IC5. The video output by the demodulator penalty is that the demodulated signal Transistor Q4, an emitter -follower is "raw" video and must be processed has only half its original deviation, but stage, buffers the video and audio -sub - before it can be viewed. The processing that can be compensated for later. A carrier information from the PLL for involves de -emphasis and de -dithering. simple FM demodulator with a center the next stages of the receiver. continued on page 104

www.americanradiohistory.com )/J AUTOMATIC Power Switches How many switches do you have to throw to get your computer or stereo system up and running? Build this power switcher and you'll need only one.

GARY McCLELLAN

ANY ELECTRONIC OR ELECTRICAL SYS- tern that uses a number of separately switched can be a nuisance components R1 D1 FI SO2 to power-up...all those switches to turn 2.2K, 1/2 W 1N4004 1AMP on. and then, having to remember to turn them all off! I had that problem with my Radio Shack TRS-80 computer C2 RY1 S03 system. TO "I` 20/250V 117 6-0-* As it grew. I quickly realized what a Cl O1 VAC WIDE SL OT MJE340 headache powering -up can be. and 0.1/600V %r SO4 tried all sorts of solutions, such as ex- R2 SO1 tension cords and outlet strips. They 1002 (TO TV) did the job, but lacked what I like to r, S05 call "elegance." for there is nothing D2 elegant about plugging in an extension 1N4004 cord! The solution is a power switcher. 03 SWITCHED It can be used with computers, on the 1N4004 OUTLETS test bench, and even with stereo equip- IH ment where there are many things to be C3 0.1µF powered up. Basically, the device is a B current -operated switch; when current - ~ flow through one of the computer devices is sensed, that turns on all the FIG. 1-IF POWER SWITCHER doesn't work with the Radio Shack video monitor, reverse the con- other equipment. nections to SO1. See text for details. In my computer application. I plug the video monitor into the power The power switcher is inexpensive want the monitor to do the power switcher. Then I plug each of the acces- and easy to build. I built my version switching. When it is turned on, it sories into the outlets on the unit. Now using junkbox parts, but I was careful draws current, causing the diodes to all I have to do to power -up my com- to use readily available components. conduct. That applies a 0.7 -volt P -P sig- puter is to turn on the monitor and And, even if you have to go out and nal to the transistor, causing it to con- everything springs to life! Not only is buy the parts, you should be able to duct, and close the relay. Don't be con- the arrangement "elegant." but I no keep the cost between $ 10 and $20 with cerned about the 0.7 -volt drop to the longer forget to turn off the computer reasonable effort and care in shopping. monitor-that value is negligible when after a late -night session. Other bonuses The switcher contains only a few parts. compared to the full 117 -volt line include the fact that no warranty - so construction should go quickly and voltage. voiding modifications have to be made easily. Building it should be a one -after- The rest of the circuit is used to to the computer or accessories, and noon project. power the relay, and for glitch suppres- that the power switch on each acces- sion. Diode DI and resistor RI make up sory still works. For example, the How it works the relay power -supply. Capacitor C2 printer isn't used all the time, so it is Figure 1 shows a schematic of the across the relay coil filters the voltage, simply shut off until it's needed. That's power switcher. Note that diodes D2 and prevents chatter. Capacitors CI great for saving wear and tear on ex- and D3 are in series with the line to the and C3 are included to keep power -line pensive mechanical components. monitor socket. That's because we glitches from the transistor, and to pre-

www.americanradiohistory.com MONITOR POWER SWITCHE4 SWITCHED OUTLETS a W 1.11 I.- 3'4 AMAX X

vent damage to the device. Finally, safety and longer component -life. Re- If any of your equipment has three - fuse F1 was included as a protective delays in the five- to ten -amp range are prong plugs, you will want to change vice for the video monitor, even though easy to find. SO2-S05 to 3 -pin receptacles as re- the monitor already has its own fuse. A Another part that many people will quired. That way you can avoid the little extra protection never hurt want to use a substitute for is transistor headaches that adaptor plugs tend to anyone. Q1. The original part is an NPN, 250 cause, and still have your equipment mA, 350 -volt -CE (Collector -to -Emitter) grounded properly. Parts substitutions breakdown -voltage devices, and is If you do make any substitutions. One of the nice things about this de- sometimes found in the audio output - make sure that all parts you use are in vice is that parts values are not critical stages of radios and TV's. Thus, you good condition for maximum safety and and a wide range of substitutions are may be able to scrounge a usable reliability. If there's any doubt, spend possible. That can reduce your cost transistor from such sources. Generally. the little extra cash necessary to get dramatically if you have a well -stocked the substitute transistor should have at parts that you know you can trust! junkbox. Of course, there are reason- least a 200 -volt CE breakdown -rating. able limits as to how far you can go: and be able to handle at least 100 mA of Construction those are dictated mainly by safety and current. The gain really isn't important, Caution: The switcher is connected di- reliability, which are the most important since the device is used only as a rectly to the power line and can present a factors. Let's look at some areas where switch. In fact, it might be possible to shock hazard if assembled incorrectly. It you may make substitutions-and then use an SCR, if you have one, in place of is suggested that you use extra care in a few where you shouldn't. the transistor. Just be sure to replace assembling it. Also, it is recommended The first thing that most people will C2 with a 1N4004 diode to suppress for safety reasons that you do not sub- probably want to find a substitute for is back-EMF, and make sure that the re- stitute for the three -wire power cord and relay RY1, a 117 -volt -AC relay with lay is an AC type. (Otherwise, the SCR metal cabinet. contacts rated at five amps. The original will latch up when a load is applied to Let's start construction. The layout. part used was designed for vacuum - SOI. and you'll have to unplug the which is not critical, will depend to a tube circuits, and is known as a "plate - switcher to turn off the computer!) large extent on the components you are circuit relay". Those devices are still in There are many substitutes for the using. The first step (after obtaining the use, and are sometimes available at MJE-340. though, if you don't have parts) is to lay them out in the box to surplus -electronics stores or by mail one. determine where they should be order. If you can't find a relay with a There are other components for mounted. In the prototype, the line 10,000 -ohm coil, you may substitute which substitutes are available. The cord and sockets were mounted on one one with a 5000, or even 2500-ohm coil. diodes may be replaced by devices with end of a box that measured 41/2 x 4 x If you happen to have a 117 -volt -DC re- a higher current -capacity or PIV rating. 21/2-4 inches. The relay and fuse were lay, and the coil resistance is 2000 ohms Diode D l should have at least a 200- attached to the bottom of the case. The or higher, it may also be used. In any PIV rating though. The ratings of the rest of the circuit, mounted on a long case, adjust the value of R1 so that the other two diodes, D2 and D3, aren't as terminal -strip, was then attached to the relay closes any time a load is connected important because neither diode will bottom of the box. Figures 2 and 3 to SO I. One thing you should make sure see more than 0.7 volts. show details of the layout. of when you select a relay is that its Some substitutions are permissable Drill the holes for the power cord and contacts are heavy enough to switch at for the capacitors, although it is sug- sockets. Then turn to the installation of least five amps of current. Although it gested that C 1 be a Mylar type: they the relay and circuitry. Generally. is doubtful that you will draw that much handle line -voltage glitches better than those components can be mounted on current with a TRS-80 computer and its ceramic discs. The other capacitors the bottom of the box, unless you have accessories, the extra capacity insures aren't critical. a plug-in type relay; in that case, mount 55

www.americanradiohistory.com Q1 C3 R2 C2 D2, 03 stranded wire). Do the same with the upper terminals. Then connect the line cord as shown in the schematic. Finally make the appropriate connections to the terminal strip and relay. Finish up by checking over your wiring for errors and correcting any that you find. Safety checks Naturally, you are in a hurry to try this power switcher-but check it out first. Since it connects directly to the AC power -line, it is a good idea to take the time to be sure that the unit is safe for use. First, inspect the wiring to be sure that there are no shorts to ground (the case) or between adjacent wiring. Correct any shorts that you may find. Then make sure that all connections are properly soldered; it's easy to miss a joint, especially on the terminal strip. While you're checking the wiring, make certain that the line -cord's ground wire (from the round prong on the plug) is in good contact with the case. Finish up by checking continuity between the case and the prongs of the line -cord plug. The resistance should be infinite on any ohmmeter range, except in the case of the round ground -prong, where you should see no resistance. If any of the readings are incorrect, recheck your solder connections, and look for SO2 S03 SO4 S05 any dirt or contamination between a FIG. 2-MAJORITY OF COMPONENTS can be mounted on an 8 -lug terminal strip. Be sure to use connection and ground. heavy -gauge wire to handle line voltage and current safely. Operation Assuming that you're using the PARTS LIST power switcher with a computer, plug it and its accessories into S02 -S05. Then All resistors 1/4 -watt, 5% unless otherwise plug the monitor into SO1 and the specified switcher's line cord into a wall outlet. R1-2200 ohms, 1/2 -watt, 10% Turn on the computer and accessory R2-100 ohms power switches, and then turn on the Capacitors monitor. C1-0.1 µF, 600 volts, Mylar The entire system should C2-20 µF, 250 volts, electrolytic spring to life, and you'll be all set to C3-0.1 µF, 25 volts, ceramic disc enjoy a computer system that's easier Semiconductors to use. To finish up, you may want to Q1-MJE-340 or equivalent (see text) install the switcher under your operat- D1 -D3 -1N4004 (1 amp, 400 PIV) ing table, as I did with the prototype, F1-1 amp fuse or conceal it way. FIG. 3-THIS PARTICULAR VERSION some other of power S01-polarized chassis -mount socket switcher did not require 3 -wire line cord, but If you have trouble getting the yours probably will. Make sure that the ground S02-S05-nonpolarized chassis -mount switcher to turn on with the monitor, wire makes good contact with case. socket simply reverse the connections to SOI. RY1-10,000-ohm plate -circuit type with The Radio Shack monitor has a half - the relay socket on an "L" bracket. SPST, 5 -amp contacts (see text) Miscellaneous: aluminum box, 3 -wire wave rectifier in it that draws current Locate the terminal strip near the relay. power cord with plug, strain relief for on half cycles of the line -current, and The fuseholder should go near SO1, to cord, clip -type fuse holder, 8 -lug termi- reversing the connections causes the which it will be connected. After com- nal strip, relay socket and bracket (if re- monitor to draw current on the same ponent locations have been determined. quired), wire, solder, etc. half cycle that is used to trigger the drill the mounting holes for them. If switcher. (That should not be a prob- you like, the outlets can be labelled is finished, mount it on the bottom of lem with the other accessories.) with press -on letters, which will make the enclosure. You can also use the power switcher them more convenient to use. The next step is the chassis wiring. to operate other devices. One applica- All the electronic components (resis- Remember that it will be carrying fairly tion that comes to mind is using a turn- tors. capacitors, diodes, etc.) can be high voltages and currents, so be sure table to control an entire sound -system. mounted on the terminal strip. Use to do the best job that you can. Mount Simply plug the turntable into SOI, and "spaghetti" insulating tubing to keep the line cord and strain -relief, sockets, the other components of the system component leads from shorting together. relay, and fuseholder. Then start the into the other sockets. That's all there Be sure to observe polarities, especially wiring by busing together the lower is to it! Once you've built it, I'm sure in the case of the transistor (see the terminals of S02 -S05 with a piece of you'll find many uses for this power inset in Fig. 1). When the terminal strip No. 18 solid wire (or tinned No. 18 switcher. R -E 56

www.americanradiohistory.com D

HOW TO DESIGN ANALOG CIRCUITS

If a circuit is not designed properly, the likely result will be a device that does not work, or a pile of charred components. Learn the right way to design analog circuits that use semiconductor components in this new series.

MANNIE HOROWITZ

AT ONE TIME OR ANOTHER, ANYONE only things we will assume is that you speak briefly about some of the num- interested in electronics (either as a have a basic knowledge of such things bers we will be using. Many of the num- hobby or on a professional basis) has as current and voltage, as well as some bers used in electronics are either very needed a circuit to perform some spe- familiarity with components such as re- large or very small. Writing numbers cial function. Most of us have found, sistors, capacitors, and inductors. (If such as 100,000 or 0.000001 con- however, that it is almost impossible to you do not have a background in those tinuously can get tedious. It is a lot design a circuit properly using hap- subjects, we suggest that you read a easier to write those numbers using hazard techniques. That is especially book on basic electronics first. Your scientific notation or exponents. In true of circuits that use semiconductors. local library is an excellent place to scientific notation, 1000 becomes 103 If proper techniques and procedures look for one.) and 0.001 becomes 10-3. are not followed, the end result is likely Only what you need to know to do Special prefixes are also used to de- to be either nothing or a bunch of actual designs will be covered here. note powers of 10. Some of the most charred components. Derivations of formulas will be avoided common are kilo (103), mega (106), giga In this series of articles our goal will except where they help make the design (IO9). milli (10-3), micro (10-6). nano be to teach you how to design analog procedure clear. When a formula is (10-9), and pico (10-12). As an example, circuits that use semiconductors. Each presented, an example showing you 0.001 volts would be written as 1 milli- article will cover one or more specific how to apply the formula will also be volt. semiconductors. As we will be starting provided. Do not try to memorize any from scratch, some of the things we'll of the formulas or derivations; simply Conductors, insulators, and be talking about may seem ridiculously make a note of where they are so that semiconductors simple to some of you. That material you can refer to them when you need When the electrical characteristics of will be presented for the sake of the them. different materials are considered, they novice, as well as for continuity. The Before we get much farther, let's can be divided into three not -so -exacting

www.americanradiohistory.com groups. Those are conductors, semiconductors. and insulators. Most of us are familiar with conductors and insulators-but what about semiconductors? A semiconductor is defined as a material whose conductivity falls some- where between that of an insulator and a conductor. Most semiconductors use either germanium or silicon as the base element. Because those elements are good insulators in their pure form, they are

mixed with another material to form the FIG. 1-A VARISTOR can be used as a current limiter. Opening the switch in the circuit shown in a useful semiconductor; that mixing is would cause a current surge (due to the presence of the inductor) that could damage the switch con- called doping. Doping the base material tacts. Placing a varistor in the circuit as shown in b would protect the contacts. has two consequences: The conductivity of the base material is increased and. rent through that inductor. Since that 250 ohms at 25°C. it is 250 x 0.96 = 240 depending on what is used for the high voltage is also across the switch, ohms at 26°C, 240 x 0.96 = 230.4 ohms doping, the base material picks up the switch contacts could be damaged at 27°C. 230.4 x 0.96 = 221.2 ohms at either an excess or shortage of negative if they are not protected. One way to 28°C. and so on. Another characteristic charge. A semiconductor with an protect the contacts would be to wire a of a thermistor is that there is a time excess of negative charge is called varistor across the switch as shown in delay from when heat is first applied to n -type; a semiconductor with a short- Fig. l -b. In that circuit, the resistance the device until it reaches its final tem- age of negative charge is called p -type. of the varistor is very small when the perature. again assuming that all of the Semiconductor materials have a wide switch is first opened, because the high - heat is supplied by an external source. variety of properties. Their resistance voltage developed by the inductor is That "thermal time constant" rating varies with the voltage across them, applied across the device. That low re- indicates the amount of time it takes for with changes of temperature, and with sistance keeps the instantaneous volt- the temperature of the thermistor to the amount of light that strikes them. In age across the switch low, protecting rise to about % of its final value. addition, any device made up of a semi- the switch contacts. The varistor has So far. we've assumed that all the conductor material is to some extent no effect on the circuit with the switch heat is supplied by an outside source sensitive to magnetic fields and can be closed, because the switch shorts out and none is developed by the thermis- considered to be a Hall -effect device. that device. tor itself. Of course, if you apply (We'll talk more about Hall -effect de- If you wish, the varistor could have enough voltage to a thermistor, some vices later.) been wired across the inductor instead. heat will be generated. Assuming this Despite the fact that it would be in the time that there is Varistors no external source of circuit even while the switch is closed. heat, the resistance of a thermistor will A semiconductor device whose re- it would not affect the circuit's opera- remain constant up until the applied sistance varies with the voltage across tion because the steady-state DC volt- voltage exceeds a certain critical point. it is called a varistor or voltage -de- age across the inductor is low. As that With no change in resistance, the cur- pendent resistor. Because of their low voltage would also be across the rent through the device increases structure, those devices are often called varistor, its resistance would be ex- linearly with increasing voltage. Once varistor diodes or current -limiting tremely high and thus negligible when the critical point is reached, however, diodes. compared to the resistance of the the device begins to heat up and the re- The difference between an ordinary inductor. sistance begins to drop. When that resistor and a varistor is that while the happens, the current will increase at a resistance of an ordinary resistor is Thermistors faster rate than the voltage. That critical constant, the resistance of a varistor A thermistor is a semiconductor de- point is called the self-heating voltage. changes with voltage. In that device. vice whose resistance changes with The last characteristic that we'll look the resistance is very low at high volt- changes in temperature. A thermistor at is the thermistor's dissipation constant. ages. As the voltage decreases, the re- whose resistance increases with increas- That constant indicates how much sistance increases. Ohm's law, of ing temperature is called a positive - power must be dissipated by the device course, applies herejust the resistance coefficient device; one whose resistance to increase its temperature by 1°C. If. of the device changes. In most varistors, decreases with increasing temperature for example, the constant is 0.6 mW- the polarity of the signal is unimportant. is called a negative -coefficient device. per-°C. the thermistor must dissipate although there are some devices where For the sake of simplicity, we will deal 0.6 x 20 = 12 mW if its body temperature it is. Just like a resistor, a varistor dis- exclusively with negative -coefficient ture is to rise by 20°C. sipates power and, as with any other thermistors in this discussion, although Sometimes you may find that you device, the maximum ratings of a varis- most of what we will say can also be need to alter the thermal characteristics tor should not be exceeded. applied to positive coefficient devices. of a thermistor you have on hand to Let's see how we can make use of How much the resistance decreases make it useful for some particular ap- the characteristics of a varistor. The with temperature is a function of the plication. That would not be necessary circuit shown in Fig. l -a consists of a particular device used. As a general if an infinite number of different types of power source, switch, resistor, and in- rule, however, the resistance decreases thermistors were available, but that is ductor. When the switch is closed, cur- by about 4% for each degree Celsius rarely the case. The circuit in Fig. 2 is rent flows through the resistor and in- that the temperature rises (above 25°C). used for that. Just determine the mini- ductor. Steady-state current is limited Once you know the resistance of 25°C, mum and maximum resistance that you to safe levels because of the presence it is a fairly simple matter to calculate require in your application and choose of the resistor. When the circuit is the resistance at any higher tempera- a device where the cold resistance is broken by opening the switch, a high ture-simply multiply the resistance by higher than the maximum resistance voltage is developed across the induc- 96% for each degree over that tempera- you require and the hot resistance is tor because of the rapid change in cur - ture. For example, if the resistance is lower than the minimum resistance you 58

www.americanradiohistory.com cidently, most photoresistors will respond to a wide variety of wavelengths. including wavelengths in the infrared u W and ultraviolet regions; those wavelengths are beyond the range of the human eye and are thus invisible. Without getting into the physics involved, there are two units commonly FIG. 2-THE RESISTANCE of a thermistor at dif- are FIG. 4-A SIMPLE LIGHTMETER can be made used for light intensity: those foot- ferent temperatures can be altered to fit the re- using a photoresistor. For such an application, candles and lux. The greater the num- quirements of a particular application by the photoresistor should be equally sensitive to lux properly choosing the values for R1 and R2. ber of foot-candles or hitting the all visible wavelengths of light. photoresistor, the greater the intensity need. Letting RTH be the hot resistance of the light source, and the lower the re- of the thermistor and RTc be its cold re- changes. Thus the current flowing sistance of the photoresistor. You sistance. R I and R2 in Fig. 2 can be through the circuit and the meter should also note that the intensity determined from the following relation- changes with temperature. It is a simple varies with the inverse square of the ship: matter to calibrate the meter's scale in distance from the light source. For a order to indicate the temperature at the fixed light source at 5 feet from a sur- (RTH + R2) R1 RH = thermistor. face. let us assume that the intensity of RTH +R2+R1 Another important application of the light at the surface is I. Now increase thermistor is in limiting current surges. that distance to 10 feet. Because the (RTH + R2) R1 The life of light bulbs, rectifiers, etc. distance from the source has doubled. would be shortened if a large current the intensity is now 1/22 = I/4. If the + R2 + R1 RTC flowed through any of those devices at distance were tripled to 15 feet. the rel- Where RH is the hot resistance re- the instant power was applied. If a ative intensity is I/32 = I/9. and so on. quired by the circuit and Rc is the thermistor were placed in series with Photoresistors are used in many dif- cold resistance required. any device, its high cold resistance ferent types of devices. The obvious As an example, let's assume that for a would limit that surge current. If the one is its application in measuring light particular application you need a therm- thermistor is properly chosen, its re- intensity when taking photographs. Be- istor with a resistance that is 440 ohms sistance will be large enough to limit the cause color is an important factor in at 25°C and 240 ohms at 50°C. You have surge to reasonable and safe currents that application, semiconductor de- a thermistor on hand with a resistance when it is cold, and be low enough not vices that respond to the entire visible specified as 600 ohms at 25°C and 210 to affect the circuit when it is hot. spectrum should be used. A circuit for ohms at 50°C. Substituting into equa- that application is shown in Fig. 4. In

tions 1 and 2, you end up with: the absence of light, the resistance of Photoresistors the photoresistor is high: thus very little 240=(210+R2) R1 As we noted earlier, not only is the current from the battery will reach the 210 + R2 + R1 resistance of semiconductor material meter. If the sensitivity of the meter is R2) R1 dependent upon temperature and low, the pointer will not be noticeably 440 = (600 + 600 + R2 + R1 applied voltage, but it also varies with deflected. With increasing light in- Solving for R1 and R2 we get: the amount of light that hits it. The tensity. the resistance of the photore- of the more R1 = 1218 ohms photoresistor takes advantage sistor drops. Now current can R2 = 89 ohms. fact that semiconductor materials are flow in the circuit: that will be indicated sensitive to light. The resistance of the by the meter. The higher the intensity. Because those values are not stan- device varies inversely with the inten- the greater the deflection of the pointer. dard, they will be expensive to buy, if sity of the light striking it. (The more Calibrating the meter is simple. you can find them at all. But using intense the light, the less resistance.) Another. more common use for the standard, readily available values such The wavelengths of visible light vary photoresistor is to control a relay, that as 1200 ohms for RI and 91 ohms for R2 from about 330 to 800 nanometers (3300 in turn is used to control some device will be acceptable for most applications. to 8000 angstroms). Different photore- or appliance. A circuit that can be used There are quite a number of practical sistors respond to different wave- to turn a lamp on at night is shown in applications for the thermistor. Among lengths-the wavelength to which a Fig. 5. Here the photoresistor is across the more common is in a temperature - particular device is most sensitive, de- the relay. The photoresistor and RI measuring circuit, as shown in Fig. 3. pends upon the basic material used for form a voltage divider. During daylight Here, the device is connected in series the semiconductor, and upon the per- hours, the resistance of the photoresis- with a milliammeter and a voltage centage of impurities added to the basic tor is low, and therefore most of volt- source. The current flowing through material. Because the device is made age is across RI. The voltage across the the meter is, by Ohm's law, equal to the from semiconductor particles, the relay coil is too low to establish the voltage divided by the resistance of the wavelength sensitivity also depends magnetic field necessary for the con- thermistor. As heat is applied, how- upon the size of those particles. In- tacts to close. As night falls, the re- ever. the resistance of the thermistor o

FIG. 3-A THERMISTOR can be used to measure temperatures. This simple circuit shows one FIG. 5-t PHOTORESISTOR and a relay can be used to turn a lamp on at nightfall. The circuit will turn way to do that. the lamp off at dawn.

www.americanradiohistory.com tions of the Hall effect is to measure the field strength of a magnet. In that application, a voltmeter is connected so it can measure the voltage generated. If the current is held constant, the voltage will be directly proportional to the magnitude of the magnetic field. (The higher the voltage, the greater magnitude.) Again, it is relatively easy to calibrate the meter to give a direct readout of the magnitude of the magnetic field. That application may seem unimportant, but its principles can be extended to give you a way to measure a DC current flowing in a conductor. As the magnitude of a magnetic field is related to the DC current in the conductor, if the voltage across the conductor is known (measured from end to end), the Hall effect lets yoU determine the current through it-without breaking the wire- simply by measuring the magnetic field. Note that the output voltage due to the Hall effect has a specific polarity. That polarity depends upon the directions of the magnetic field and the current. The polarity is also a function of the type of semiconductor material used. If it is n -type, the polarity will be opposite from the polarity when p-type THERMISTORS ARE HOUSED in a wide variety of enclosures for different applications. Among the material is used. Thus the Hall effect enclosures shown here are ones for air, water, and surface temperature measurement. can be used to determine the type of semiconductor material. The easiest The Hall effect way to apply that is to note first the Perhaps the easiest way to describe polarity of the voltage when a known the Hall effect is with an illustration. type of material is used. Next substitute such as the one in Fig. 6. In that figure. any unknown semiconductors. Com- the cube is a piece of semiconductor pare the polarity of the voltage. If it is material. If the cube were placed in a the same, the semiconductors are the magnetic field B. and a current I flowed same type; if it is different, the semi- through it. then a voltage V, perpendi- conductor is of the opposite type. cular to I and B would be generated. The devices we've looked at this The voltage that is generated is propor- month have been relatively simple, yet tional to the product of I and the magni- they are quite useful in analog circuits. tude of B. If either the current or the Be sure to include those devices in your FIG. 6-THE HALL EFFECT is shown here. With magnetic field are missing. no voltage arsenal. When we continue this series, a magnetic field B, and a current I as shown, a a that is used in a voltage V will be generated that is perpendicular will be generated. we'll look at device to both B and I. One of the most important applica- wide variety of applications-the diode. R -E

sistance of the photoresistor increases. as does the voltage across the relay's coil. Once the voltage across the coil is high enough, the contacts close, turning on the lamp. The procedure is reversed at dawn, turning the lamp off again. Of course, safety should be a prime con- i cern when building that, or any other. N ©l7 circuit. Wires should be rated high enough to handle the currents that they N will be carrying. The relay's contacts SvL óó should be capable of handling the switching that will be required without pitting. and be rated high enough so that there will be no breakdown or arcing. Just as with any other device, a photoresistor has certain ratings that should not be exceeded. Never exceed oC7 the specified limits of voltage, current, or power; doing so will destroy "These video war games sure are fun. Dad.... I'll bet you didn't hare this much fun the device. at the very least. in the real war!" 60

www.americanradiohistory.com I I I . .LI

o LJ IMPROVE VIDEO SOUND

Dissatisfied with the sound quality of the videotapes you make? Here are several ways to improve it.

LEN FELDMAN CONTRIBUTING HI-FI/VIDEO EDITOR

HOME VIDEOCASSETTE RECORDERS. LIKE or portable VCR directly to your com- of VCR's take to "simplify" the audio ,V receivers, tend to place more ponent stereo -system, you know that sections of their products. emphasis on the quality of the picture the frequency response of the sound- than on that of the sound. While the track on a videotape is not all that bad. Live -taping situations color pictures reproduced from video- When VCR's are operated at their Most VCR's are equipped with a tape are often indistinguishable from fastest speeds (0.79 ips for Beta -format single microphone -input and, in some those obtained from good, off-the -air machines or 1.31 ips for VHS machines) cases, another high-level input. Home- TV reception. The sound portion of the audio response often extends to "ideo cameras usually have built-in those recordings, however, seem almost beyond 10 kHz, while the signal-to- omnidirectional microphones that are to have been tailored for reproduction noise ratio may be as high as 45 dB or connected to a VCR by the multi -pin by the small speakers and minimal - more if high-grade tape is used. While camera cable that has become fairly power amplifiers found in most table- those specifications are not outstanding standard on this type of equipment. In top TV receivers. in high-fidelity terms, they would be any case, there is no means of con- If, however, you have ever connected more than adequate for general use trolling audio gain at the camera, nor is the audio -output jack from your home were it not for some steps that makers there a master level -control at the

www.americanradiohistory.com VCR. The VCR is equipped with an ALC (Automatic Level Control) circuit that restricts the dynamic range of the audio severely. The ALC can cause problems when the built-in camera microphone is used as the sole sound -pickup device in a home -videotaping setup. The reason is that, more often than not, the camera and microphone are several feet away from the subject being taped, and the resulting soundtrack has an echo -laden, reverberant quality that is incongruous when heard together with close-up views of the subject (taken with the aid of a zoom lens). Background noise also increases, be- FIG. 1-A MIXER, such as the Shure M267, allows you to use several microphones or other audio sources. cause the ALC circuit is doing what it was intended to do (maintaining a con- m stant audio level-even if the only is 0 ..111M111. audio irrelevant background-noise), Lil and the effect is anything but natural - c sounding. In addition, if the camera is hand-held or shoulder -supported (rather than being mounted on a tripod), one CL can often hear the sound of "heavy 0 breathing" from the camera operator CC because of his proximity to the camera - w mounted microphone and the "wide open" gain that is provided by the ALC circuitry. -20 The solution to the problem, ob- Q viously, is to use an off-the -camera li 20 50 100 500 1 K microphone (or microphones), pref- cc erably of the directional or cardioid FREQUENCY-Hz type, It can be kept just out of camera FIG. 2-LOW-CUT FILTERS can reduce the annoying effects of wind noise turntable rumble, and range, but still be positioned close other low -frequency sounds by decreasing low -frequency response. enough to the subject or subjects being taped to give good solid audio. Whether you choose a dynamic on their tapes. (Shure also manufactures meter is illuminated for easy reading microphone or a condenser type, the a model M268 mixer that includes many when the mixer is AC -operated. plugs found on the higher quality, low - of the features of the model M267, but However, the model M267 will op- impedance microphones are not likely sells for $250.00.) erate either from AC or from an external to fit directly into the miniature jacks The model M267, shown in Fig. '1, battery pack. In case of an AC -line failure found on most portable and home has wide frequency -response (30 Hz to or power interruption, noiseless auto- VCR's. However, adaptors that con- 20 kHz, ±2 db) and low distortion up to matic switchover to the batteries takes vert from one type of plug to another +18-dBm output (less than 0.35% at place. Battery -charge condition can be are readily available from electronics - +15 dBm at any frequency within its checked at any time. A front -panel parts stores. passband), extremely low noise, and monitoring jack will drive just about very low susceptibility to RF inter- any mono or stereo headphones, and a Audio mixing ference-a problem that can often crop separate level control is provided for It's just one step from using a single up in an untested "field" environment. the phones. Finally, a built-in 1000 -Hz external microphone to using several Four switchable microphone or line - tone oscillator is incorporated for line microphones and even some line -level level balanced inputs with individual tests and level checks. program -sources (like music from gain controls and low -frequency rolloff The low-cut filters associated with records or tapes). Using multiple switches are provided, and the output each of the four LINE/MIC inputs pro- sources instead of the single -micro- is switchable for either line or micro- vide a low frequency roll -off that fol- phone approach is also preferable when phone levels. Thus, if your video lows the response curve shown in Fig. dubbing a new audio -track onto your camera is equipped with only an ex- 2. The filters can be used individually existing videotapes. ternal -microphone input (and there is with each input control to reduce wind Shure Bros. (222 Hartrey Ave., no line -level input on your VCR), you noise or undesirable low -frequency Evanston. IL 60204). a well known can still get the benefit of good signal- signals, such as turntable rumble, or manufacturer of phono pickups, micro- to-noise ratios. overly bassy voices caused by speakers phones, and professional audio equip- There's a built-in peak limiter-to- or singers holding microphones too ment and accessories, has introduced gether with an LED peak-indicator- close to their mouths. recently a small, 4-input audio mixer, that can cut distortion due to overload; the model M267. While it is intended it can be switched in or out. The sen- Better audio dubbing for use primarily in audio -recording ap- sitivity of a small VU meter can be set Most of the owner's manuals supplied plications. the versatile, relatively inex- for +4 or +8 dBm with a VU RANGE with VCR's suggest that the proper pensive ($395.00) mixer can also solve a switch (normally, 0 dB on the meter is way to do audio dubbing (the process lot of problems for serious videophiles equal to +4 dBm; the +8-dBm setting whereby a new soundtrack is substituted who want better -quality soundtracks is used to reduce sensitivity). The for the original one) on a videotape is 62

www.americanradiohistory.com MIXER TO MIC INPUT

TO MIC INPUT

LINE OUTPJT VCR FROM MIXER TO LINE INPUT ON AUDIO TAPE DECK

FROM AUDIO OUT TAPE DECK (TO LINE INPUT ON MIXER) FIG. 3-A MASTER AUDIO TAPE is prepared by using a mixer to combine the orginal video soundtrack with new material.

TO AUDIO IN FROM LINE OUT

TAPE DECK DUB BUTTON DEPRESSED FIG. 4-THE ORIGINAL SOUNDTRACK is replaced by the new one by transcribing the master audio tape to videotape using the VCR's "dub" function.

simply to plug a microphone (or a mixer VCR. The synchronization process is duces a still -frame picture on the such as the one we have been describ- not as difficult as you may think, at least screen), used in conjunction with the ing) into the external -microphone jack for scenes of relatively short duration. PAUSE button on your audio tape -deck, of the VCR, hit the AUDIO DUB button, After all, the final mixed tape contains should permit a close -to -perfect audio- and substitute new audio for the old. the original "live" soundtrack, which dubbing operation. (As for the VCR's There are several disadvantages to is already perfectly synchronized with speed stability, you don't have to that procedure. For one thing, it erases the video. Since the same audio -tape worry because its tape -transport sys- the original soundtrack, which you may deck is used both to record and play tem is synchronized to the standard want to include in the new sound mix. back the final mix, tape speed-even if NTSC 30 -frames -per -second picture Secondly, working in "real time" and not perfectly accurate-will be consis- rate.) getting all the musical and voice por- tent for the brief periods needed to Imaginative use of a microphone/line tions to fit together, on cue, during the transcribe the new audio mix back onto mixer, together with playback through very first "take" is a rarity-if you've the videotape via the audio -input jack your sound system rather than through ever tried it, you know that the task can on the VCR. your TV set, can give your home -video be extremely frustrating. With practice, the PAUSE control on productions near-professional audio A much better technique involves the VCR (which, in most cases, pro - quality. R -E transcribing the existing audio soundtrack from the videotape onto audio tape and, with the aid of a mixer, adding the additional microphone or line -level contributions, as shown in Fig. 3. If you don't get the "perfect" mix the first time, you have not destroyed the original videotape soundtrack and can try again-as many times as you need to get it right. Figure 4 shows the hookup for the final audio -dubbing process. In that step, of course, it is necessary to syn- chronize the newly mixed audio master -tape with the VCR program using "My Mom says it's a radio. ... Boy, it must take a lot of bat- the audio -dubbing feature on your teries to run one that size!"

www.americanradiohistory.com LJ UHF-TV PREAMPLIFIER

TV-Matchinn Trans former

This inexpensive UHF preamplifer can give you reception you never thought possible, especially if is used with a good antenna system and feedline. RAY PICHULO

LAST MONTH, WE tion" VHF/UHF antenna. While that transmission. Smaller antenna size, Part 2 looked at the pre- may seem at first to be a good solution, and therefore a smaller signal capture - amplifier that could improve your UHF the results are little different from area, is another factor contributing to reception. We'll finish up by showing those obtained by city dwellers with poor UHF reception. you a balun for use with coaxial cable, their "rabbit ears" and loops-while but first, let's look at other factors that the VHF quality may be good, that of Improving the antenna system can affect your reception. the UHF is, generally, fair or poor. A Let's take the advice of the FCC and Today we find that, in most urban look at combination-antenna specifica- industry committee and see how an an- areas, receiving antennas are dis- tions will usually show that the per- tenna system can be improved. The appearing from rooftops. Indeed, many formance of the antenna at UHF fre- July 1981 issue of Radio -Electronics viewers are getting satisfactory results quencies is poor, with little or no gain. contains an excellent article with a on VHF channels 2 through 13 using Let's take a moment to consider TV comprehensive rating of many antennas just built-in "rabbit ears." There may design -practices. Until recently, UHF with UHF capability that are now on be several reasons for that: better VHF tuners never even had an RF -amplifier the market. The first step is to get away tuners, higher transmitter powers, stage. Even with the addition of such a from the ineffective ones, so we'll for- better -located transmitting antennas, stage in most of the UHF varactor get about loop antennas and take a and-regrettably-the fact that many tuners, sensitivity is lower and the noise close look at the UHF gain-specifica- people just don't recognize poor pic- figure higher than with VHF tuners. In tions of the "combo" antennas. Unless ture -quality or know how to correct it. many parts of the world, most TV the gain of those antennas is in the Many of those viewers usually use a broadcasting takes place at UHF fre- neighborhood of 7 dB or better on the simple loop antenna attached to their quencies and the receivers sold must UHF channels we are interested in, we TV sets' antenna terminals for UHF meet certain UHF sensitivity and noise - should consider using separate UHF and don't care whether or not they get figure criteria. (In simple terms, `'noise and VHF receiving antennas in areas more than one or two channels-or figure" is the decrease in apparent sig- where signal strength is not classified even if they get anything at all. nal-to-noise ratio caused by inherent as "strong." As you travel out through the suburbs system-noise.) Such needs don't exist Probably the simplest effective UHF and into the near-fringe areas where an for TV sets sold in the U.S. receiving antennas are the corner re- external antenna is still a necessity, The reception problem is compounded flectors. Most of them will give at least you will probably notice that most of by the higher transmission -line and 7 dB of gain. If more gain is required, the installations use a single "combina - propagation losses inherent in UHF either a combination corner reflector/

www.americanradiohistory.com obvious, the effect of trees and foliage is not. Dense foliage can create a path loss of 20 dB or more. Sometimes it may be impossible to get a clear line -of-sight shot to the transmitting antenna. Reception may

6 still be possible using reflected or scattered signal. When that technique

5 is used, though, the actual physical placement of the antenna becomes ex- 0 tremely critical because the signal is 0 arriving via several different paths. Remember, we are dealing with wave-

ÿ 3 lengths measured in inches, so a lateral 300C2SHIELDED or vertical move of only six inches can TWIN LEAD (BELDEN 8290) result in a change in signal quality. Feedlines LOW LOSS RG6 TYPE The next item to consider is the feed - (WINEGARO CL -2800) line. Several types of feedline are available and most installers know that good quality, low -loss, feedline is important for UHF. Many, though, do not know what makes a feedline low -loss. For example, many installers insist that you should never use coaxial cable at UHF frequencies because it is lossier than twinlead. Few people are aware,

0.7 however, that the biggest contributor to 100 200 300 400 500 600 700 800 1000 coaxial cable's lossiness is its woven FREQUENCY -MHz 11 1 I I I braid. UHF signals travel most ef- 14 18 35 52 69 83 ficiently in a straight line, something UHF TV CHANNEL NO. they can't do in a woven -braid conduc- FIG. 12-LOSSES IN VARIOUS TYPES OF CABLE measured in dB/100 feet. Ordinary twinlead would tor. However, low -loss coaxial 'cable seem to be best, but has serious shortcomings (see text). using an aluminum foil or aluminized Mylar as a shield does permit the signal yagi or a stacked 4 -bay antenna can be antennas was optimized for the best to travel in a straight line and has a used. Either can provide gains ranging gain on the middle channels. significantly lower loss than the equiva- from 8 to 15 dB, depending on their size In many cases, that won't be a major lent conventional coaxial cable (RG - and number of elements. Examples of problem, but if you're interested in re- 59/U or RG -6/U). corner reflector/yagi antennas are the ceiving high -end channels, you may The other major factor contributing Radio Shack. U-100 or the Winegard want to look further into the catalogs. to coaxial cable's loss figure is dielectric CH-9085. A good stacked 4 -bay anten- You'll probably discover that there are loss. That can be reduced by using na that was recommended in the article antennas optimized for the high end as is the Winegard KU -420. Antennas well. They are usually called "T -band" A kit of all parts for the UHF preamp, in- having even higher gains-on the order or "translator band" antennas, and cluding power supply and balun (the of 15 to 20 dB-are also available. They should be suitable for high -end channels. balun will be discussed next month), is are of the parabolic -reflector type and available for $34.50 plus $2.00 for shipping are usually between 3 and 6 feet in Installation and handling. An assembled version is diameter. After you've chosen an antenna, the available for $57.50 plus $2.00 for ship- Before you buy any antenna, though, next step is its installation. There are ping and handling. Both are available you should check the manufacturer's several considerations unique to UHF. from: published gain -vs. -frequency data. The line -of-sight principle is the main RaySon Electronics Corp. the curves may surprise you. concern; if it is at all possible, try to Some of 1010 12th St., Suite 5 For example, most UHF antennas do select an antenna site where the anten- Sparks, NV 89431 not cover the full 70 channels (14 na has a clear shot at the horizon. through 83). Instead, you will probably Ideally, the elevation angle to the hori- Micromart find that their best performance is in zon should be 0 degrees; however, 508 Central Avenue the range of channels 20 to 55, with a satisfactory performance can still be Westfield, NJ 07090 gradual dropoff above and below them. obtained with an angle to the horizon of (201) 654-6008 The reason is that channels 70 through up to ten degrees. Close-by obstruc- Quest Electronics 83 are allocated as translator-band tions are to be avoided. Buildings, P.O. Box 4430 69 will channels, and channels 60 through trees, hills, or similar obstructions Santa Clara, CA 95054 were originally reserved for subscrip- seriously degrade the received signal. (800) 538-8196 (except CA) tion -TV use. At the low end of the In some cases a mast or tower can pro- (408) 988-1640 band, channels 14 through 20, in many vide the necessary extra height to clear areas, are shared with the land mobile obstructions. While the effects of steel - All suppliers accept MC and VISA. Please Ja radio service. So, the design of most frame structures and hills is pretty add sales tax where applicable. nv 65

www.americanradiohistory.com foamed rather than solid dielectric - least two inches separation should be material in the cable. The effects of maintained for coax; more in the case 000PS! both factors can be seen in Fig. 12. of twinlead. That precaution reduces the The parts placement diagram (Fig. 8) which shows a comparison of the losses possibility of hum or noise pickup. that appeared in Part I of this article of various types of feedline used for Where cables enter a building, feed - (March 1982) was inadvertently re- UHF. At 470 MHz (channel 14) con- through bushings should be used-the versed. The correct diagram appears ventional RG -59 coaxial cable has a cables should not be jammed under heloN. loss of 9 dB per 100 feet; the Belden windows or doors! 8211 foam -dielectric version of the If you are using twinlead, it is espe- same cable has a loss of 7 dB per 100 cially important to keep the cable at ft., while the Winegard CL -2700 low - least four inches away from all metallic loss cable (foam dielectric and solid surfaces-gutters, downspouts, alumi- shield) has a loss of 5.8 dB per 100 feet. num siding, the antenna mast, rotor Since a 3 -dB loss represents a 50% cable, power cables, etc. In many cases power loss, the low -loss cable has more that will prove to be a difficult or impos- than twice the power -transmission ef- sible task; that is when coax should be ficiency of RG -59 cable. Larger diam- used. eter cable such as RG -6 or RG -11 has Excess cable -lengths should be cut even greater efficiency because of the off, not wound into a coil or bunched greater conductor spacing and the re- up. That is particularly important in the sultant lower dielectric -loss. Low -loss case of twinlead, for you can end up un- RG -6 type cable (CL -2800) is more ef- wittingly creating an RF choke. (Run- FIG. 8-TRANSISTORS ARE MOUNTED from ficient than shielded twinlead (type ning twinlead down through a metal etched side of board. "F" connectors are mount- 8290). conduit, such as the mast, can have the ed from unetched side. So far, we've been talking about dry same effect.) cable or twinlead. While moisture doesn't affect coaxial cable, because the dielectric is sealed in by the outer jacket, it does affect twinlead greatly. To see just how much, consider some figures supplied by Channel Master. At the low end of the UHF band (500 MHz) their best twinlead, type 9555 is twice as lossy wet as it is dry. The feed - line has foam -clad conductors encased FIG. 13-BOARD FOUND INSIDE balun, showing addition of 10µH choke and power leads. in a polyethylene jacket. As you go down the list, the feedlines listed have with the pliers. That will prevent any progressively less foam around the con- Baluns possible damage to the threads of the ductors, until you get to type 9561, If you are using coaxial cable you will female "F" connector from taking which is more or less conventional need two impedance-matching trans- place. (You may want to purchase a twinlead with just a solid polyethylene formers, known as baluns. One must be male -to-male connector for the pur- web. The wet attenuation -factor of that of the outdoor type, because it is pose. since you will probably need it feedline is 100 times or more greater mounted between the outdoor preamp later when you connect the antenna than the dry attenuation -factors. and the antenna. The other is used in- balun to the preamp.) (Remember: -20 dB represents a doors, at the TV set. It must be mod- All the baluns have three DC block- power reduction of 99%!) ified slightly to form a "bias -T," which ing -capacitors already built into them, That data should convince you that will permit both the TV signal and the so all that is necessary is to add a small is wet twinlead to be avoided if at all current that powers the preamp to travel choke. The choke. L I in Fig. 11 (see last possible. You should also bear in mind along the coax, while providing sepa- month's issue). is the same as choke L4 that the figures are for new cable. Ex- rate terminations for both at the set -end used in the preamp-31/2 turns of No. 30 posure to the elements causes poly- of the cable. wire -wrap wire wound through a small ethylene to become contaminated, in- There are several baluns available ferrite bead. The bead is small enough creasing its dielectric loss and, there- that lend themselves very nicely to that to fit inside the transformer's housing. fore. the loss of the cable. application. Among the ones you might As shown in Fig. 13. one end of the No. On the other hand, coaxial cable is wish to use are the MCM Audio TVT-1, 30 wire is soldered directly to the center protected by an outer jacket, and de- the RMS Electronics MA 1000UV, the pin of the "F" connector, while the gradation of the cable occurs much Channel Master 0782 and the Arista other end is soldered to the rivet that more slowly. Before the dielectric can 267A. secures the twinlead pigtail to the become contaminated. the protection All the baluns mentioned have an "F" balun's circuit board. The rivet be- provided by the outer jacket has to fail. connector pressed into a short length of comes the +V terminal and the positive So although. at first, the lower losses of aluminum tubing with a pigtail of 300 - lead from the power supply is soldered twinlead would seem to favor it use ohm twinlead sticking out the other to it. The body of the "F" connector over coaxial cable, when you consider end. The aluminum tubing is covered becomes the ground terminal and the the life of an installation. coaxial cable with shrink tubing. To open a balun for ground lead from the power supply is gives better results. modification, cut away the shoulder of connected to the connector by being sol- the shrink tubing at the base of the dered to the ground foil on the small Installing feedline "F" connector and then remove the circuit board. Many an otherwise good installation connector, and the board attached to it, The UHF preamp is easy to build is ruined by poor feedline-installation. by pulling it out of the aluminum tubing. and, when used with the type of anten- No matter which type of feedline you It may be necessary to use pliers for na installation described, will do a lot to use, care must be taken to keep it away that operation; if so, thread a male improve the quality of your UHF -TV from power and telephone cables. At connector on temporarily and grasp it reception. R -E

www.americanradiohistory.com L J

WHAT'S INSIDE

ANALOG ANALOG DIGITAL FILTER OUTPUT INPUT

DIGITAL DIGITAL CONTROL FILTERS SIGNALS

Filtering an analog signal using digital techniques is becoming more and more commonplace. Here is a look at digital filters and how they work.

ARTHUR MAKOSINSKI

TRADITIONALLY, ACTIVE AUDIO -FILTER If a signal at the commutating fre- tor therefore charges to a fixed voltage, designs have used either L -C or R -C quency, fc, is now applied to the filter. and as the individual capacitors are networks in combination with phase- or each individual capacitor sees a par- switched in, or commutated, the origi- gain -compensating amplifiers. While ticular-and fixed-average voltage nal signal is reproduced as a series of such filters are relatively simple and (the voltage is dependent on the phase discrete values or steps. economical when designed for one or of the input frequency) each time it is The commutating filter is often called two frequencies, they become complex switched into the circuit. Each capaci - a comb filter because it will only pass and expensive if required in large num- signals with a frequency of fc-the bers, as, for instance, in a 1/2 octave resonant frequency of the filter-and audio -spectrum analyzer. A device its harmonics. That response is shown with a 20 -Hz to 20 -kHz range would re- in the graph of Fig. 3. If, however, only quire over 30 separate bandpass filters, the resonant frequency is desired, low- or 360 precision capacitors and resis- pass filters can precede or follow the tors for filter -tuning alone. That is in commutating filter, attenuating the addition to the problems of achieving other "teeth" of the comb. adequate temperature and amplitude In modern commutating filters, the stability, as well as maintaining accept- commutating is done by shift registers able reliability. or counters. Standard transistors, or With the development of digital IC's FET's, can be used to switch the in the late 60's, designing digitally con- capacitors. Figure 4 shows an eight - trolled audio filters became possible. section commutating filter in which the FIG. 1-A MECHANICAL commutating filter. If the first designs was is One of considered, the input signal is equal to the switching fre- necessary sequential switching done the digitization of the old mechanical quency, the filter would reproduce the input by a combination of a CD4040 BCD commutating -filter; that filter is shown signal at the output as a series of steps. ripple counter and a CD4051 BCD -to - in Fig. 1. decimal decoder. The CD4040 counter is triggered by a squarewave clock sig- Commutating filter -3dB nal. As the counter advances, on the How the commutating filter works negative -going clock transitions, the can best be understood by considering RELATIVE first 3 bits of its 12 -bit BCD output are the simple low-pass section of Fig. 2 as AMPLITUDE -dB connected to the BCD input -lines of the an integrator with a time constant T = CD4051 decoder. That IC translates the RC. If n such sections are cascaded and BCD code into sequential decimal steps sequentially switched at a rate off times that switch the internal CMOS transis- per second, the net time -constant in- tors on and off; those transistors, in creases by n, so that the new time -con- f LOW PASS - t switch the connected capacitors. FREQUENCY -Hz 27rRC turn, stant ? = nRC. That will yield a 3 dB In the frequency is a FIG. 2-THE RESPONSE of a simple low-pass that circuit, filter's low-pass response at fLow PASS filter is shown here. The time constant of the function of the clock rate, and the num- = l /(2nRC ). curve is determined by the values of R and C. ber of poles, or sections, in the filter. In

www.americanradiohistory.com and its bandwidth becomes sharper. To cuit the input resistor has been replaced minimize the filter's step non -linearity. by a switched capacitor. For those of the capacitors that are used should you that are unfamiliar with integrators, have a tolerance of less than 10%. An and as a review for the others, let's take R -C low-pass filter at the output of the a brief look at how that circuit is used commutating filter can attenuate sub- as a low-pass filter. stantially any of the clock signal at the Due to the action of the capacitor in output and improve linearity. Precau- the feedback loop, if the input signal to tions should also be taken so not to the circuit has a relatively low fre- overload the input of the filter; that quency, the output will be the integral 0 fc 2fc happens if the peak -to -peak input volt- of the input-hence the name integrator. FREQUENCY-Hz age exceeds the positive supply voltage But if the input frequency is high FIG. 3-A COMMUTATING FILTER can also be to the decoder. enough, the feedback capacitor does called a comb filter since, at resonance, it not have time to charge, and the op - passes the fundamental frequency and its Switched -capacitor filters amp's output remains constant (i.e. harmonics. Although this sounds suspiciously DC). The filter's cut-off frequency is like the commutating filter, the switched - determined by the values of the resistor +10V capacitor filter works in quite a dif- and capacitor. ?16 ferent way. Since the resistor in Fig. 6 has been

11 In its simplest form, it is an R -C low- replaced by switched capacitors, that R 1.1- C D4040 CLOCK C, 8 pass filter where the capacitve elements filter can be tuned by simply altering 10 Q Q2 Q3 -*(112 are fixed, and the resistive elements are the frequency at which the capacitors

9 substituted by "switched -capacitor" are switched (clocked). As an additional resistors. Later on, we will see how the precaution against internal parasitic +10V 11 switched -capacitor circuit can even capacitances, the configuration shown

A B C 6 simulate an L -C filter, but first, to un- in Fig. 7 is used. If that circuit is 16 1NH CD4051 derstand this odd resistor substitution. clocked properly, it can also be used to let's take a look at Fig. 5. In Fig. 5-a. simulate the inductor currents and 0 1 2 3 4 5 6 7 is in position A, the capacitor voltages a 14115 1211 5 12 4 = when the switch of passive L -C cir- capacitor charges up to voltage V1. cuit. Here is what happens: 1I 11.1 When the switch is flipped to position The d) clock signal is '80° out of o 1wv 11 Ti T l o B. the capacitor will discharge to volt- phase with respect to the clock sig- VIN (LESS THAN 10V P-PI VOUT age V,. The amount of charge flowing nal. Let's feed the d, clock signal to Ql 0 o into (or from) V2 therefore equals and Q3. and the signal to Q2 and Q4. C(V, -V1) During the first half cycle of the clock Now, let's replace the analog switch pulse, only QI and Q3 will be "on" and FIG. 4 -USING A BCD COUNTER and 8 -channel the cir- capacitor will up value decoder IC's to control a commutating filter. with a pair of FET's, and drive Cl charge to the The filter is tuned by changing the clocking fre- cuit with a clock pulse. as shown in Fig. of VIN. Assuming VIN to be positive. Cl quency. 5-b. If the capacitors are switched at a will charge up so that point b will be clock rate, fc. then the average current positive with respect to point a. During Fig. 4, since there are 8 poles, the filter's flow I from V, to V2 will be I = C(V, - the second half cycle, only Q2 and Q4 primary response frequency, in Hz, will V1)fc. Since R = V/I, a resistor that will be "on" and the voltage across be: woud give the same average current I capacitor Cl is applied to the inverting fc = clock frequency - number of poles as a switched capacitor could be cal- input of the integrater. However, since culated from R = I/Cfc. point a is negative with respect to point The filter will also pass the harmonics Therefore, it would seem that any re- h. the overall affect is that of a non -in- offc. and its bandwidth will be 2 divided sistor in an R -C filter could be replaced verting integrator. The output will have by the number of poles. times the band- by a switched -capacitor. That, how- some phase lag, in addition to the 90° width of the single, original low-pass ever. turn out not to be a practical ap- phase lag of an ideal integrator, caused section. If the resistor's value is 10.000 proach when working with IC's because by internal delays. ohms, and the capacitors are .01 uF of the internal cross -coupling that is Now, let's change the clock inputs to each, the filter in Fig. 4 will have a caused by self- and parasitic -capaci- the filter. The 0 clock signal is now fed practical, continuous turning range of tances. to Q2 and Q3 and is fed to Q1 and from IO kHz to over I MHz. and a Q of The most widely used type of IC low- Q4. During one half of the clock cycle. 80. pass filter is an op -amp integrator. If the only Ql and Q4 will be "on" and One problem is that the CD4051 is switched -capacitor filter shown in Fig. capacitor Cl is shorted through ground not exactly an ideal switch. Its typical 6 seems to resemble an integrator, there and discharges to zero. During the "on" resistance, with a supply voltage is a good reason: It is-but in that cir- other half of the clock cycle, Q2 and Q3 of 10 volts, is 180 ohms, and it increases as the supply voltage is lowered. While that will rarely affect performance, G G since the other resistances in the filter V1 V2 are generally much greater (consider Q1 Q2 the 10,000 -ohm resistor we just mentioned), in some cases individual v1 V2 transistors would be better. If you wish, additional decoders can be added to the other BCD outputs of the CD4040 ripple counter-al- a together the CD4040 can drive five de- b coders. As more decoders are added. FIG. S-THE SWITCHED -CAPACITOR technique shown in a is realized in an IC by using the circuit the filter's output becomes smoother shown in b. In b, the two FET's replace the mechanical switch.

www.americanradiohistory.com TABLE 1

Digital Filter Commutating Switched - Transversal Type Capacitor

Filter response comb bandpass bandpass high pass !ow pass low pass chirp Notch Frequency range <.5 Hz - 10 MHz .5 Hz -25 kHz 1 kHz -1 MHz higher with ECL FIG. 6-AN INTEGRATOR is often used as a dB low-pass filter in IC's. In the circuit shown here, Dynamic range >80 dB >40 the input resistor has been replaced by a Distortion depending on <.1% <.1% switched capacitor. types of Clock residue switching elements, etc. 6 mV not specified are "on" and since the capacitor is dis- Input signal maximum 10 V p -p 3 V p -p charged, it appears as a short and VIN is Input impedance high >100 kilohms 200 kilohms applied directly to the inverting input of Output impedance high <1 kilohms <1 kilohms the integrator. The circuit shown in Stopband depending on 80dB >40 dB Fig. 7 now behaves just like an inverting number of sections integrator whose output has slightly Skirt steepness} switching elements 60 dB/octave 150 dB/octave Insertion loss z20 dB ?15 dB less lag than 90°. <±.2dB Center Frequency absolute better than better than It is a simple matter to connect the .1% so accuracy .5% integrators in series and clock them Technology used any: TTL, CMOS, MOS MOS that every other integrator is of the ECL, transistors same type. If that is done, the slight Parts cost/filter $3.00 > $28.00 $40.00

variations in phase angle will be can- (quantities of 1 - 9) celled. The resulting circuit will behave just like a low selectivity L -C network. As the differences in phase will be can- nique is still relatively new, several filter. Each IC is housed in a 16 pin DIP celled regardless of the clocking fre- manufacturers are beginning to use it. and requires minimum of +5 volts for quency. that switched -capacitor filter Among the IC's using that technique are operation. Reticon is extending their can be tuned by simply changing the American Microsystem's (3800 Home- high -end usable frequency to 20 kHz. clocking frequency. stead Road. Santa Clara, CA 95051) and the low end to .5 Hz. The clock to By using the techniques we've dis- S3505 and Mostek's (1215 W. Crosby center -frequency ratio of the R560x cussed. it is possible to simulate com- Road. Carrollton. TX 75006) MK5912. family is approximately 108:1, and the plete networks of various types of Those IC's are telephone -system coder - insertion loss is typically 0 dB. An on - single- and multi -pole filters. What's decoders: both make extensive use of chip flip-flop divides the clock fre- important from a manufacturing view- switched -capacitor filters. quency by two so that the switched - point is that switched -capacitor resis- EG&G Reticon (345 Potero Ave.. capacitor is switched at 1 the clock fre- tors require very little silicon area-in Sunnyvale. CA 94086) uses switched - quency. fact the area decreases as the value of capacitors in three general purpose. One problem with most sampled data the resistor increases. In practice, a 10- digital -filter IC's-the R5604. R5605, systems is that input frequencies at megohm resistor is needed if the filter's and R5606. The R5604 contains three 6 - rates about I/z of the switching fre- capacitor is to be kept to a reasonable pole Chebyshev 1/2 -octave ANSI Class quency may be mistaken for the filter's 10 picofarads. A resistance of 10 III filters that together cover an entire center frequency (aliased) and may megohms is obtained if a 1-picofarad octave with one external input -clock appear at the filter's output. Reticon capacitor is switched at a frequency of trigger. The R5605 contains two 6 -pole recommends using an external R -C net- 100 kHz. If, in place of the switched ca- Chebyshev 1/2 -octave ANSI class Ill fil- work at the IC's input. if input signals pacitor. a 10-megohm resistor were ters that, like the R5604. cover a full greater than 27 times the center fre- actually used in the IC. it would require octave with one external input -clock quency are expected. 100 times more space. trigger. The R5606 contains one 6 -pole Another small drawback with those Though the switched -capacitor tech - Chebvshev full -octave ANSI class II IC's-at least at present-is cost. Reti - con sells the R560x series IC's at prices

C2 that range from $28.00 to $48.00 each. in small quantities. Dl a Transversal filters S D Another monolithic digital -filter that 1 VO UT is beginning to be used in some applications uses a novel combination of a 03 0- o 64 simulated multi -tap delay line and synchronized periodic sampling. Like the previously discussed filters, the o transversal filter uses a trigger clock to S VI N "tune it" to the desired frequency. While its exact operation is quite complex, and beyond the scope of this article (if you are interested in a more FIG. 7-PARASITIC CAPACITANCES can be reduced further by using this circuit. If clocked properly, co several of them could also be combined to simulate a passive L -C filter. complete discussion, see Reticon's ro 69

www.americanradiohistory.com o o CLOCK FREQ. = 100 kHz -10 ANALYZER BW 1 kHz -10 10 = 1000 Hz =

10 = 109 kHz -20 EXT AMP GAIN = 15 dB -20 co a -30 N -30 ó -40 o - -40 z -50 á -7:3 -70 -60 < -80 -70 -90 DEVICE NOISE FLOOR -80 100 02 03 04 06 08 1.0 20 30 40 50 o 10 15 20 25 30 35 40 45 50

NORMALIZED FREOUENCY-f!10 FREQUENCY -kHz

THE BANDPASS CHARACTERISTICS of a Reticon R5604 switched -capacitor filter is shown in a. Con- trast that to the frequency response of the Reticon R5602-3 transversal filter, shown in b.

grammed characteristics. Texas Instru- ments (PO Box 225474, Dallas, TX 75265) has also developed an advanced 1024 -stage transversal filter with an 8 - amm. ,..K .111.11111/ ,®. .111110 .._ .., ...... 810 v ._. v .eremos bit programmable response -characteristic and Q. in addition to a 60 -dB dynamic range, 50 -dB stopband at-

tenuation, and a 1 -MHz maximum filter frequency. No mention was made of the low -frequency capability. At the time of writing, neither the Reticon nor the Texas Instruments filters were com- mercially available. Applications With features like broad frequency - capability, digitally programmable cen- THE CLOCK INPUT to a commutating filter, and the resulting output is shown here. The signal input ter frequency, and, in the near future, to the device is a sine wave. programmable response characteristics, digital audio filters-and especially the switched -capacitor and transversal R5602 Transversal Filter Family Data and skirts, with a 150 dB -per-octave types-are a natural for use in com- Sheet for details), let's take a brief look roll -off rate. The same aliasing prob- puter -controlled networks. With those at how it works. lems found in switched -capacitor filters devices, a t/3 -octave spectrum analyzer Basically, the IC uses a new MOS can impair the transversal filter's per- could be built using only one filter IC to charge transfer technique to form a formance if input circuitry is not care- cover the whole range from 20 Hz to monolithic bucket brigade. The bucket fully designed. The Reticon R5602 20 kHz. If proper anti-aliasing measures brigade is a chain of N -channel MOS family requires more outboard circuitry are taken at the filter's input, switching transistors connected to small monolithic than their switched -capacitor counter- the clock frequency will be all that's storage capacitors. The input signal is parts, as well as a +15 -volt power needed to sweep the filter through the sampled, and the sampled charge is source. They cost $40.00 each in quan- entire range. Some other applications transferred from one capacitor to the tities of less than 10. could include harmonic analyzers, pro- next by alternately switching the MOS Presently, a general limitation with grammable noise analyzers, modems, transistors. the transversal filters is their poor low - and any kind of audio or sub-audio As the sampled charge is transferred, frequency response, which, in turn, is a filter. R -E it is simultaneously summed with a function of the minimum sampling fixed analog reference. Thus, at every (clock) frequency required to shift the clock transition an alternate pattern of capacitor voltage levels along the signal samples and reference charges bucket brigade. That "refresh" rate are shifted forward. By multiplying the must be fast enough not to allow loss of sampled and reference values by pre- charge in the capacitors due to leakage. programmed weighting factors and Currently, those filters can be used combining them at the output, various down to input frequencies of at least responses can be simulated. l kHz. The Reticon transversal filters con- Recently, Reticon reported work on tain a 64 -section bucket brigade, as well a transversal filter IC that uses double as timing and output circuitry. Like the polysilicon low -loss capacitors, extend- switched -capacitor filters, transversal ing the low -frequency response down filters are available in several configura- to 50 Hz; the high -frequency limit is 125 tions including low-pass and bandpass kHz. The IC has a dynamic range of "Oh! You mean you wanted nre to filters. over 65 dB and, what is perhaps most clean the videodiscs with the disc- The filters have linear phase response remarkable, it offers digitally pro - n'asher?

www.americanradiohistory.com FIRST PART (M Keypad Determining the status of a key Part 2 thiE,s article, in the The program, located in an EPROM (pressed or unpressed) is done by scan- April 1982 i,sue of Radio -Electronics, (Erasable Programmable Read -Only ning the keypad. That is done in two described the theory of operation and Memory). that controls -he video titler steps. First, a bit -pattern is written to the construction of a 6802 microprocessor - has three sections that deal with the output port to select a specific row. A based video t tier for your VCR. This keypad: recognizing when a key has logic -0 represents a selected row. A part will discuss, in general terms. been depressed, recognizing which key logic -1 a non -selected one. Then, the some of the programming techniques has been depressed, and debouncing status of every key in the rpw selected that are used to make the device operate. (turning into a clean poise) the "key - is read through the input port. A logic -0 The purpose of any computer pro- pressed" signal. indicates that a key has been depressed. gram is to accept data, process it. and The 40 -key keypad is arranged as Since there are eight columns in each produce an ot_tput based on the results five rows of eight columns each. It uses row, and since each column is repre- of processing that data. two microprocessor ports-one for in- sented by a bit, a column with no keys In the case 3f the video tiller. the input to the microprocessor located at depressed will be read as FF (hex). put comes from the keypad. The pro- lO (hex) and one for output at 800 which represents a bit -pattern consisting cessing consists of recognizing which (hex). Note that only five of the eight entirely of logic -1's. Any column that keys have been pressed, and the output bits available at the output port are has a value less than FF (hex) has a key is a series of instructions to the VDG used for keypad control (one for each depressed. and the position of the logic - ( Video Display Generator) that results. row of the keypad): the others are for 0 within the bit pattern tells which key ultimately, in a video signal. VDG mode -selection. in the column it is.

FOR HOME VIDEO MOV

Last month we showed you how to build and use a video titler for your VCR. Now we'll take a look at how it works.

www.americanradiohistory.com xI- LL, VALID N SIGNAL C:J (\ .-L rL r2 v M N B J ¡' Q Q Q Q Q Q I O U I= ILL I¢ IQ IQ U Z Iz (.7 U' } DEPRESS RELEASE n40 n39 n38 n37 1136 [13517341-1331-13217311-1301129 n281127 n261125 (124n231122n21 NOISE NOISE FIG. 12-KEY BOUNCE generates noise that MC6847 can confuse the microprocessor when a key is pressed and released. The text explains how the valid signal is extracted. U1 U2 U3 U4 U5 U6 U7 118 U9 U1011111112U131114U15U16U17111811191120 üQ CO m M m (O U 9 ÿ ^ O Q > p O O O 2 S 6 > Q Q Q1 Mechanical switches, such as the U keys of the keypad, present a problem for logic circuits. Even though you may FIG. 13-MOTOROLA'S MC6847 video -display generator IC is the heart of the video titler. have pressed the key only once, its contacts can continue to bounce against BIT 7 6 5 4 3 2 0 each other after you press it and after

you release it (see Fig. 12). That X PAGE CSS R4 R3 R2 RI RO bounce is confusing to the microproces- since it sees each one as a separate sor, ,1 KEYBOARD ROW SELECTION key closure-not what you intended at NOT USED MEMORY VDG the keys, it is all. To "debounce" FIG. 14-A DATA BYTE contains information describing the character to be displayed, which page it necessary to wait until the contacts are is to be taken from, and what its background color (CSS) will be. stable, and then read their status. That is done by making the assumption that typically a key will be depressed for blocks of color (a full screen would create the display. If both sections try about 300 milliseconds and that the consist of a 64 x 32 array of colored to access the memory simultaneously, maximum bounce duration is about 20 display elements, each one made up of the VDG will miss some data, and the milliseconds. The sequence of instruc- an 8 X 12 array of dots). display will be incomplete. tions the microprocessor follows in de - The VDG receives its instructions To keep that from happening, a syn- bouncing and in determining which key from the display memory (located from chronizing signal is provided through has been pressed is as follows: 2000 (hex) to 23FF (hex)). Each an input port located at 1800 (hex). Bit 1. Select a row. memory address contains a byte repre- 6 of that port, when cleared, means that 2. Read the input port. senting the information to be displayed. the microprocessor can access the 3. If the value equals FF (hex) then If the most significant bit (bit 7) of the memory; when it is set, the VDG is read the value of the next row byte is a logic -0. then a graphics char- using it. A routine that guarantees a (and so on, until finished). acter will be displayed; if it is a logic -1, period of 2 milliseconds during which 4. If the value is not FF (hex), then will char- can access the wait 100 milliseconds (that is a the result be an alphanumeric the microprocessor check for key bounce). acter. The memory is divided into two memory is shown in Table 1. 5. Select the same row. sections (2000 (hex) through 21FF (hex) 6. Read the input port. and 2200 (hex) through 23FF (hex)), to Programming 7. If the value equals FF (hex) then provide two separate "pages," or dis- This section will describe, in general it was key bounce, so go back to plays. Page selection is made by setting terms, how the video titler is pro- step one and start again. or clearing the page bit (bit 6), as shown grammed. 8. the other rows to Check all in Fig. 14. The "CSS" bit (bit 5) is used First, two tables relating specific make certain that there is only select the background color-red or keys to specific characters have to be one key depressed (value less to an alphanumeric character. One table is for the alphanu- than FF (hex)). green-for created. 9. Read the input port. Note: Each byte presented to the meric mode; the other for the graphics 10. If the value is not equal to FF VDG must contain the keypad -scan in- mode. The values for the tables are de- (hex), then more than one key is formation, the page bit, and the CSS bit. rived by multiplying the row number depressed. Go back to step one It is important to remember that the (0-4) by eight and adding it to a column and start over. display memory is accessed by both the number (0-7). Each value corresponds 11 Execute the function determined microprocessor for inputing data and to a particular alphanumeric or graphic by the value of the depressed by the VDG for retrieving data to continued on page 76 key. 12. Wait for the key to be released. TABLE 1 Check all lines until only FF (hex) is read. 13. Delay about 30 milliseconds. WAITS FOR THE END OF CURRENT MEMORY ACCESSIBLE PERIOD 14. Go back to step one and start again. WAITLO LDA A $1800 READS VDG FS SIGNAL Display AND A $40 TEST BIT 6 BNE WAITLO The video display is generated by an MC6847 video -display generator IC. Its WAITS FOR THE END OF VDG SCAN. pinout is shown in Fig. 13. It can operate in 12 different modes, but the WAITHI LDA A $1800 video titler uses only two of them-the AND A $40 "internal alphanumerics" mode and BEQ WAITHI what's called the "semigraphics-4" NOW YOU ARE SURE THAT YOU HAVE A MAXIMUM PERIOD FOR USING mode. The alphanumeric mode is used DISPLAY MEMORY. to display characters, while the semi - graphics mode is used to generate 72

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CIRCLE 14 ON FREE INFORMATION CARD

www.americanradiohistory.com HERE ARE TWO DIFFERENT DISPLAYS that can be created using the video titler. The one on the right uses both the graphic and alphanumeric modes.

The cursor takes the form of a rect- angular cyan picture-element. Every time a data key is depressed, the key number is computed and given a value between 0 and 39 if the shift lock is not set, and between 40 and 79 if it is. (The shift lock is used only in the CHARACTER mode.) That value represents a memory location in the character table or graphics table stored in the EPROM. The contents of that memory location are moved into the display memory at the cursor position after waiting for VDG synchronization. The cursor is then advanced one position (in the HORIZONTAL mode) or 64 positions (one entire line, so it is directly above or below the previous position) in the VERTICAL mode. THE PROGRAM that controls the video titler is located in an EPROM. That IC is easy to spot here-It If the cursor is to be displayed, the con- Is the one with a round quartz window. tents of the display memory at the new position are saved, but not seen until the cursor moves on. continued from page 72 lowing information: [f a function key is depressed, things character and is written into memory Cursor position (two bytes repre- get a bit more complicated. The pro- when the appropriate key is depressed. senting an address in the display gram has to test the key number and, memory). (The correspondence between the keys depending on the key, jump to the sec- Contents of memory at the cursor and the values assigned them is stored tion of the program that contains in- in the EPROM.) position (one byte). Page number (one structions for performing its function. Second, two blocks of variables, byte equal to 40 (hex) or 00 (hex)-see Fig. 14). That portion of the program has to be each containing the current status of CSS (one byte equal to 20 (hex) or executed before the keyboard scan can one of the two display pages, are re- 00 (hex)-see Fig. 14.) be resumed. quired. Each block contains the fol - Row number (one byte). The video-titler program has a starting Column number. location of F800 (hex) and memory lo- Flag indicating ORDERING INFORMATION "cursor on" or cations FFFE and FFFF, which are the "cursor off." reset interrupt -vector, must contain the The following are available from Flag indicating alphanumeric or Scripto- address of the first instruction that the vision, Inc.. P.O. Box 535, Slowdown grahic mode. Sta- program will tion, Montreal, Quebec, CANADA H3X 3T7 Flag indicating whether shift lock execute on reset. (all prices shown are in U.S. dollars); as- is on or off. One last thing. don't forget that the sembled and tested titter, $168.00; partial Flag indicating direction of cursor stack pointer has to be initialized, and kit (PC board, programmed EPROM, key- movement (vertical or horizontal) the screen cleared (by writing 80 (hex)) board, enclosure, keyboard label), $69.00; There are two types of keys on the into each address of the display PC board and programmed EPROM, video titler's keypad: those are the data memory. $49.00; programmed EPROM only, $35.00. keys and function keys. The data keys That should give you some idea of U.S. residents must add 4.7% to those are used to select the characters that what makes the video titler tick. Much prices for Import duty. Please add $3.85 will be displayed: the function keys are to each order for shipping handling. more information can be found in and used to move the Allow 4-6 weeks for delivery. cursor. erase. select Motorola's data sheet on the MC6847 modes. etc. video -display generator IC. R -E

www.americanradiohistory.com L L L J D J _ L_ L- L

Have you ever wondered how a manufacturer gets the right to use the Underwriters Laboratories' symbol, and what that symbol means to you? In this article we'll look at some of the provisions of UL's electronic test equipment standard, and see what they do to find out if a piece of equipment meets it. JACK DARR SERVICE EDITOR

MOST OF US KNOW ABOUT UNDERWRITERS connected to the metal case of the in- chassis for some time now. An AC -cur- Laboratories, and the product -testing strument. All line cords must have a rent meter is placed in series with a 1500- that that non-profit organization does. strain -relief clamp at the point where it ohm resistor that is bypassed by a 0.15 They test all kinds of products that, if enters the case. One of the tests UL µF capacitor as shown in Fig. 1. Using poorly designed, could cause injury. performs is to apply a 35 -pound pull to that setup, the leakage current between Among the kinds of products they look that cord: The case must not cut the the case and the AC hot-line must not at is electronic test equipment. Recent- cord, and the cord must not come loose read more than 0.5 mA AC, or 3.5 mA ly, we received a copy of their Standard or break. for equipment with RFI filters in their for Electrical and Electronic Measuring Another provision is that the fuse de- AC inputs. ,,,.. and Testing Equipment (UL -1244), and vice used must not break the "safety - Another thing they look for is whether we thought you might like to know ground" circuit. It should be placed so any user -accessible parts could possibly about some of its provisions. that it opens the black wire-the hot give an electric shock. They define a The purpose of the Standard is to side of the line. "user -accessible part" as anything an op- make sure that each unit is as safe as Testing for leakage current is also erator might touch accidently while he possible for the user. Samples of each done. If you've done TV service work, is using or adjusting the device. Figure instrument are tested, under operating the test should be familiar to you- 2 shows a UL technician checking an conditions, in one of the four UL labs. we've had to use it on line -connected oscilloscope for just such a hazard. They look for more than just shock hazard, and some of the tests may sur- r Drop tests I prise you; they did surprise me! SHIELD (IF IDEAL I The "drop test" has long been an REQUIRED) CURRENT- electronics joke-but that is a test that METER Shock hazard 150052 L UL takes seriously. The equipment Of course, one of the things they do T they test is "dropped" a few times to T look for is potential shock hazards. For f ° see if it can withstand "reasonable 0.15 abuse." In fact, each of three samples all AC -power instruments in metal I cases, the AC line -cord must be of the 3 - of a piece of hand-held equipment is conductor type; black (hot), white L J dropped three separate times from a (grounded side of the AC line) and green FIG. 1-SCHEMATIC DIAGRAM of the test setup distance of three feet. Each time, it is (earth ground). The green wire must be used by the UL to test for leakage current. turned so that a different part of the in-

www.americanradiohistory.com strument is faced down, and the result of each fall is examined. For bench, portable, and floor - mounted equipment, each unit is tilted up until the bottom is 315/16 inches from the floor/bench, then let go. It must fall back upright, and not fall Over "oh its next face." That is done for each of the four edges of the bottom. Impact tests Providing that the unit survives the drop test, an impact test is done on all equipment except hand-held units. The test involves hitting the instrurrtent with a steel ball weighing 1.2 pounds. For the top, the ball is dropped from whatever height is needed to,produce an impact of 2 newton -meters ,,(1.5 foot- pounds). For the sides, the ball is suspended on a cable, and sà'urig down like a pendulum to give the same impact -force on each side. The meter -face doesn:t get away, either. It must be subjected to an impact -force of 0.226 newton-tñeters. A special ball is used and it is dropped onto the meter face from whatever height is required to give the specified impact. In addition to the drop and impact tests done on their cases, oscilloscope CRT's are also checked. For CRT's with a diameter of 6 inches or less, a special device called an impáct-hammer is used. That has a spring -loaded cylinder with a ball -shaped end. The device is cocked, then tripped so that the FIG. 2-A PIECE OF EQUIPMENT will not meet the UL Standard if any part that could give an electric end of the cylinder delivers an impact shock is accessible to the user. Here, a UL technician is examining an oscilloscope for a potential of 0.5 newton -meters (0.37 foot-pounds) shock hazard. to the CRT's screen. For larger scopes, the screen must withstand an impact of 2 newton -meters (1.5 foot-pounds). To perform the test, the scope is turned screen up, and a steel ball is dropped on 117 - TO FILTER VAC } CAPACITORS it from the required height. Implosion protection +117v CRT's, of course, should provide -sav CHASSIS GßOUND adequate protection from the effects of ` an implosion. To test that, UL breaks , ^ 60V -- the CRT and looks closely at the results. The implosion is caused in one of two WITH A "HOT" CHASSIS, the chassis ground is always about 60 volts above or below true ways. The "thermal -shock" method in- ground, depending on which side of the AC line is "hot" volves scratching the neck or funnel of the tube with a glass cutter in one of SHOCK PREVENTION three prescribed patterns. The scratched areas are then either heated by applying HERE'S SOMETHING THAT THE UL STANDARD outl) Reversing the line plug does no repeatedly a glass rod that has been does not cover-and it's not intended good at all. warmed almost to its melting point, or to-but that I though I should mention I recommend using a 1:1 isolation because we are talking about safety. A transformer at all times. The trans- cooled by applying liquid nitrogen re- great rrny of the newer TV sets use a former should have a high enough peatedly. full -wave bridge rectifier connected rating to handle the highest load you The other way is called the "impact" directly across the AC line (see above) might expect; usually something like method: A hole is made in the top of the for the primary DC supply. That means 200. watts is ample. I've had one of case, and the end of a 1 -inch metal rod that the chassis ground is ALWAYS at those on my own bench for years; it is rested at the junction of the funnel least at 60 volts above or below true feeds a separate AC receptable that and the screen. An 11 -pound weight is ground! If your test equipment uses I've labeled ISOLATED. (On my bench it then dropped through a five-foot guide the line ground as a common, you can also goes through a true wattmeter, tube and hits the top end of the rod. (If cause carnage just by hooking up the which I've found helpful in dealing with power-supply problems, but such the CRT doesn't break, they add more ground lead of the instrument. (You weight!) do not have to ask me how I found a set-up is not required.) R -E The scattering of glass from the im-

www.americanradiohistory.com LEAD

INSULATING CONTACT TIP COLLARS HANDLE (REMOTE TERMINAL) -rJ UNACTUATED RETRACTED e INSULATING BODY LEAD a

COLLARS PUSHED SHIELD OR TOGETHER PROTECTIVE COLLAR CONTACT TIP (REMOTE TERMINAL) EXPOSED

REMOTE TERMINAL FIG. 5-THE REMOTE TERMINAL is completely insulated in the probe (a) until the handle's collars are pushed together as shown in (b). FIG. 3-TO PREVENT YOUR fingers from accidently slipping down to the uninsulated part of beams must be on, and they must be accidently slip down to the remote the probe, the handle should have a collar such so they generate the terminal, with rather nasty conse- as the one shown here. positioned that maximum amount of X-rays. quences. While, strictly speaking, the After the equipment is set up as collar is required only on probes used a to measure peak voltages of 1000 volts LEAD described, X-ray levels are checked at distance of 2 inches from the surface of or more, it is a good thing to have on the unit. The X-ray levels are averaged any probe-even a few hundred volts over an area of 1.55 square inches and can smart! Alligator clips must also be FLEXIBLE must not exceed 0.5 milliroentgens-per- properly insulated; one method for that INSULATING hour. The test is performed with any is shown in Fig. 4. BOOT ALLIGATOR CLIP doors or covers that would be open Another type of probe that meets the (REMOTE is the spring -loaded type TERMINAL) during normal use open or removed; a UL Standard second test is performed with any shown in Fig. 5. In that type of probe, doors or covers that would be open or the remote terminal is not exposed until removed when servicing the instrument the two collars on the handle are pushed open or removed. together. The remote terminal can either FIG. 4-A FLEXIBLE INSULATING BOOT located be bent, as shown, or straight. over an alligator clip will not make the clip any Test probes All probes and test leads, of course, harder to use, but will protect against accidental shocks. One thing that is common to many must be adequately insulated. The types and brands of test equipment is lead's insulation must have a rating at plosion is observed. The equipment un- test probes. The UL Standard calls for least as high as any voltage that it might der test is placed in its normal operating insulating all types of probes to minimize be connected to. That is checked by in- position, on a support that is about 30 any possibility of shock. In addition, all spection. In addition, a high voltage is inches high (equipment that normally connectors and terminals should be de- applied to the probe assembly to see if stands on the floor is tested standing on signed so that no area that could give an the insulation might break down under the floor). Two barriers, each 91/2 inches electrical shock is exposed when they those conditions. high, are placed on the floor at 11/2 and are fully mated. That is one standard The mechanical strength of the probes 6 feet from the front of the CRT. The that has been met in most instruments is also tested. That is done with a floor is covered with non-skid material. for quite some time. Instead of the old- machine. The probe is hung by the end, The Standard requires that no piece of style banana jacks, most instruments and an arm on the machine pulls it up glass heavier than 0.007 ounces pass use recessed jacks. The plugs on the and then releases it. The probe hits a the first barrier, and no glass at all pass test leads are insulated with soft rubber hardwood surface at the end of the the second. The total mass of all glass or plastic. (Remember the old banana drop, which simulates what happens particles between the two barriers must plugs with a set -screw on the side to when you drop a probe against a bench - not weigh more than 1.5 ounces. Two hold the wire? Those could, and did, leg or the floor. The test is repeated 50 samples of each piece of equipment are "bite" you if you touched the end of times! tested. the screw!) No metal is exposed when There you have some of the things the leads are plugged into the device. that the UL does to make sure our test X-ray emissions One fringe -benefit from that setup is equipment is not just useful, but safe. All devices are tested for excessive that the rubber or plastic acts as a Of course, there is a lot more to it (the X-ray emissions. That is done by setting strain -relief for the test leads, making it Standard itself is a 60 -page document), up the equipment for normal use and considerably harder to break them right but that should give you some idea of adjusting the line voltage to the highest at the plug. what a piece of equipment must go permissible value (for a device rated at The test -probes have always been in- through before the manufacturer has 105-130 volts AC, the line -voltage is set sulated, at least to some extent. The the right to use the UL label. Incidentally at 130 volts AC). For the test, the unit Standard requires, however, that the there is a difference between the state- is set up in such a way so that the maxi- construction of the probe minimize the ments "UL listed," and "meets UL mum possible amount of X-rays are possibility of accidently touching the specifications." Only equipment that produced. In the case of oscilloscopes, remote terminal (the part of the probe has been tested by UL can be called the beam pattern must not exceed that touches the circuit). That means UL listed. The statement "meets UL 13/16 X 13/16 inches, or the smallest pos- using a protective "collar" at the lower specifications" does not necessarily sible display, whichever is larger. In end of a probe as shown in Fig. 3. The mean that UL has tested a piece of addition, for dual -track scopes, both collar is there so that your fingers can't equipment. R -E

www.americanradiohistory.com HOBBY CORNER

A new "contest," and notes from the mailbag EARL "DOC" SAVAGE, K4SDS, HOBBY EDITOR

THE OTHER DAY. I WAS ASKED HOW TO to me about problems, answers, or items from Thailand. Just as we do, the build the smallest possible audio oscil- whatever. Your letters are appreciated, Thais use newspapers as packing ma- lator. It seems that my neighbor was especially when you come up with a terial. Noel sent along a couple of pages trying to squeeze an oscillator into a solution to another reader's problem. from a Thai newspaper. case that was already overcrowded. There are a couple of things, how- Now, I don't read a word of Thai. In My first thought was that a transistor ever, that will make things better for fact, it might as well be written in is smaller than an IC, so the oscillator both of us. Send your letters to me at Greek. To be accurate, Greek would be should use one. Well, the smallest cir- the New York office. Use this address: better-I might be able to recognize cuit I could come up with is the simple Radio -Electronics something. In this case, I could only device shown in Fig. 1. Of course, it 200 Park Avenue South read occasional things like "30K," turned out that the output transformer New York, NY 10003 "BACK E.M.F.," and some digits. is larger than the rest of the compo- If you mail anything except subscrip- Nevertheless, I was fascinated by the nents. Perhaps using an IC would not tion information to the Subscription Thai newspaper because when I turned be such a bad idea after all. Department in Colorado, it is not only the page, I found that I could read part That brought me to the circuit shown delayed but it may be misdirected. In of it! There at the bottom of the page in Fig. 2. Excluding the speaker, the addition, please take special care to was a schematic with the same symbols circuit still requires four components. identify each sheet of your correspon- and numbers that we all know. In its favor, however, is the fact that no dence. Perhaps the easiest way to do That Thai writer was communicating output transformer is required. that is to stick a return address label on with me halfway around the world, and each page. Unless the pages are marked in his own language. As Noel pointed tsv in some way, they may become sepa- out, the schematic was unmistakably a 21%13904, rated, never to be rejoined. There are capacitance -operated switch. Any of us 21,122.22, two reasons why that may happen: have built that circuit from RS 200 could the First, your letter may go to/through article. several people before it gets to me. In SPKR spite of our best efforts, things some- Adjustable LED indicator times get separated-especially en- In the December Hobby Corner, velopes from their contents. Second, Leonard Eisner asked for help in de- and perhaps more important, is the fact signing a circuit that would turn on an FIG. 1 that my filing system leaves a great deal LED at selectable voltage levels. +v to be desired. Well, the system itself is Leonard Dennis of Atchison, KS sent not so bad-it's just that I forget to use a very good circuit that uses one-fourth it until things begin to fall off the stacks of an LM3900. It can be adjusted over a that I toss them onto. Repeated New very wide range and turns on an LED Years' resolutions have not resulted in when the voltage exceeds the selected any lasting improvement. level. The little problem was brought to mind by a package I received recently-without envelope, of course. Some- TE ST one named Bob sent me three issues of a magazine from the 1930's. The ac- FIG. 2 companying note thanked me for I fooled around a bit with the design sending him something (What?), indi- and managed to come up with a circuit cated that the unwanted magazines that used just three parts, but the results could be returned (Where?), and that were not satisfactory. those I kept would be deducted from We have not given up. Sooner or the amount(????). later we'll stuff a tiny oscillator into Well, I am completely in the dark. that case. In the meantime, let's have a It's like starting to read a book in the contest-we'll see who can come up middle. So, Bob, write again and let me with a design that takes up the least know what to do with the magazines. amount of space. In a later column, I'll They must have some special value, publish the smallest that I receive and it would be a shame for them to (schematic only, please) before mid- hang around here until they get lost. FIG. 3 night June 1, 1982. Universal language I want to show you a circuit (Fig.3) When writing The most interesting things turn up in that was sent to me by Ronald Holder Certainly, I want to do nothing to the mail. Noel Nyman of Seattle, WA of Bridgman, MI. It is unusual because make it more difficult for you to write works for a company that receives the voltage that is measured is also

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CIRCLE 21 CN FREE INFORMATION CARD

www.americanradiohistory.com used to power the circuit. rain in the gauge. Several sensors are setting his digital clocks. He wants a. The measured voltage (from 5 to 36 attached to the inside of the gauge's battery circuit that will take over, at volts) is applied to the point marked tube, at appropriate levels, and the least for a short period of time, when TEST. The LED is turned on if the volt- leads from them are run into the house the AC power fails. age exceeds the level set by adjusting using a multi -conductor telephone I agree that the situation is annoying. the 50.000-ohm pot. Of course, the cir- cable. Inside the house, each sensor especially when the power is off for just cuit will also drive a small relay or (one at a time) is connected by a switch a second or so. After all, even the old audio buzzer, if desired. to the alarm circuit. Mark the switch so electric clocks had to be reset after they that you know which sensor is con- were off for a few minutes. But to have More on the rain gauge nected by each position; when the to reset it after a few flickers?-that is Kent McSwain of Albemarle. NC, alarm sounds you will know the water exasperating! sent a great improvement on the rain level in the gauge. Thanks for sharing Let's help Clifford out. What kind of gauge discussed in the November issue. that idea with us. Kent. a battery circuit can you come up with He did not like the idea of having the to run your clock for short periods of weight of the water turn a potentiometer. It is "time" again time? Remember, that your circuit has Kent suggests using a regular water- L.V. Clifford of New Port Richey. to be small enough to fit into the clock's alarm circuit to measure the amount of FL wrote in to say that he is tired of re- case. R -E

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82 CIRCLE 37 ON FREE INFORMATION CARD CIRCLE 55 ON FREE INFORMATION CARD

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CIRCLE 18 ON FREE INFORMATION CARD

www.americanradiohistory.com COMMUNICATIONS CORNER

Shortwave listening on a budget HERB FRIEDMAN, COMMUNICATIONS EDITOR

I HE WAY IT LOOKS THESE DAYS. WE ARE the radio's tuned antenna -input circuit. FROM TO living in the age of two computers in Unfortunately, frequency converters ANTENNA 01 RECEIVER 40601 OR every garage and a microprocessor in are subject to image -frequency inter- 40673 everything else. Communications de- ference. The best way to explain image - GI vices are not any different. Just brows- frequency interference is with an ex- ing through any of the magazines de- ample. In Fig. 1, we beat the desired voted to our hobby would lead one to 7.05 -MHz signal against an 8.05 -MHz

believe that nearly all communications oscillator to get the desired 1 -MHz out- receivers use at least some digital cir- put. But if there is a signal at 9.05 Mhz,

cuitry, if not a microprocessor. (the image frequency), it will also beat r 120K .01 SHORT FOR In fact, that is just about right. But against the oscillator, producing a 1 - COAX FEEDER OR 01 there are still some of us around that MHz output from the mixer. That is LONG WIRE T don't have the means, or the desire, to image -frequency interference. The only XTAL 10 02 spend the equivalent of a couple of way to eliminate the problem is to 2N2222( C3 months salary for the latest "break- select an oscillator frequency so that through." There are still some hams there is no signal on the image fre- LI/C1 = DESIRED FRED 9-12 L2/C2= CONVERTER VDC who haven't traded in their old gear just quency. (Keep in mind that the output OUTPUT FRED 100- so they can listen to the new amateur can be anywhere in the broadcast band.) L3/C3 = XTAL FRED 15052 bands. And there are many newcomers to our country who might like to listen TO RECEIVER to a shortwave broadcast from their old homeland, but can't afford even the FIG. 2

least expensive non -digital receiver. 1 MHz ceive a 14.9 -MHz signal. Are you con- For those hobbyists, there's little fused about why tuning the receiver to value in the new-and expensive- a higher frequency would let you re- "computerized" receivers. In fact, ceive signals that are lower in fre- they would probably get more out of an quency? It is because the frequency of old but reliable device called a crystal - the converter's crystal oscillator is controlled converter. To bring it up to higher than the frequency of the desired date, we'll simply substitute solid-state signal. Thus, the output of the mixer is FIG. 1 technology for the old tube -design. 25 MHz -14.9 MHz, or 10.1 MHz. If A crystal -controlled converter is a Let's take a closer look at how a con- the oscillator's frequency were below rather unsophisticated, low-cost device verter works. For this example, assume the SW-signal's frequency, tuning the that converts SW signals to the tuning you've reworked a surplus Navy re- receiver to a higher frequency would let range of any available receiver. Figure ceiver that has a tuning range of 1.5-12 you receive signals that were also higher 1 shows how it works. Assume that the MHz, but you want to monitor 15 MHz in frequency. desired signal is on 7.05 MHz, and all with a minimum of image interference. The preceding examples are the that's available to the listener is a broad- We'll use a 25 -MHz crystal oscillator in primary uses for crystal -controlled con- cast -band radio with a tuning range of our converter. The 15 -MHz signal is verters. While it's difficult to locate a 550 to 1600 kHz. The signal from the beat against the oscillator to produce a shortwave converter these day, if you antenna is fed into the mixer through a mixer output of 10 MHz. That output is have had any experience with winding tank circuit that is resonant at 7.05 fed into the receiver, letting you hear your own coils, and you own or can MHz. The output of an 8.05 -MHz the 15 -MHz signal when you tune to 10 borrow some form of dip meter (that de- crystal oscillator is also fed into the MHz. As for the image, it's at 35 Mhz, vice is used to determine the resonant mixer. The output of the mixer consists a little -used frequency that's sharply at- frequency of a tuned circuit), you can of the original 7.05 -MHz signal, the tenuated by the converter's tuned in- probably use "junk -box" parts to sum of the signal and the output of the put -circuit. throw together a converter for the fre- crystal oscillator (7.05 MHz + 8.05 While this is essentially a fixed -frequencies below 30 MHz, such as the MHz = 15.1 MHz), and the difference quency device that is tuned by changing one shown in Fig. 2. between the signal and output of the the oscillator's frequency, depending That circuit has not been optimized crystal oscillator (8.05 MHz - 7.05 MHz on the "Q" of the converter's tuned for performance; it's strictly an experi- = 1 MHz); the output of the mixer is circuits, you should be able to tune mental project whose values have been fed to the broadcast -band radio. If the through a narrow range of approxi- selected to provide some level of opera- radio is tuned to 1 MHz (1000 kHz) it mately 500 kHz by simply adjusting the tion using, within reason, almost any will actually receive the 1 -MHz compo- receiver's tuning control. For example, components. For instance, you can nent of the mixer's output-the 7.05 - if the receiver is tuned to 10.0 MHz it trim the performance for the specific MHz signal. The other components of will receive a 15 -MHz signal; but if it transistors you use. Don't hesitate to the mixer's output will be attenuated by were tuned to 10.1 MHz, it would re - make changes; it's almost impossible to

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A formula race car and A/S's new Model M-710 Formula -1 are more alike than you'd guess. The engineering strategy is identical: continually refine a proven basic design, within a set of strict operating parameters such as electromagnetic propagation and transmitter power, with one objective: MAXIMUM POSSIBLE PERFORMANCE. That's Formula -1, the direct descendant of A/S's original classic base - loaded low -band mobile police antennas, and the culmination of over 25 years of continuous design development. Born for performance, built to last. Formula -1 is today's new state-of-the-art in mobile CB antennas.

Precision -wound, water-proof Big Momma" type coil. Cool running -x100 reserve power factor. Lifetime burnout guarantee. Factory tuned for general use: set -screw ultra -fine tuning. Longer whip for more "reach' 17-7 PH stainless steel whip. Taper -ground to minimize range-robbing wind deflection at highway speeds. Anti -static whip ball -tip for less noise, better safety. New quarter -turn quick -disconnect. Lite tested over 2,500 times. 17' pre -assembled cable, miniature in -line connector for easy installation. Contour -forming protective mounting gasket for finished appearance. Complete hardware for both roof -top or trunk -lip mounting. 5 -year limited warranty. Formula -1 performs like a formula should ...and overtakes anything else on the roads. Available now from your CB dealer.

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www.americanradiohistory.com "blow" anything. true for the other tank circuits.) A mental or overtone type. If it is an over- Transistor Ql is a diode -protected second tank circuit, made up of C2 and tone type, the output frequency will be dual -gate FET. A 4060 is suggested be- L2, is tuned to be resonant at the con- slightly different from the marked or cause it's specifically intended for use verter's output frequency (for example, calculated value; again, you can com- in a mixer circuit. But if all you have 1000 kHz). A third tank circuit, made pensate for that by adjusting either C3 around is an RF amplifier such as a up of C3 and L3, is tuned to be resonant or L3. 40673, give it a try. Transistor Q2 is a at the crystal's frequency; tune that Please keep in mind that the con- small -signal high -frequency NPN tank circuit so that the oscillator verter we've described is intended as a transistor. Any general -replacement "starts" reliably each time power is "junk box" or "experimental" project. type (such as a 2N2222, etc.) should applied to the converter. The adjust- Even so, while it won't perform mir- work. ment of C3 (or L3, if you chose to make acles, it will do a creditable job. R -E The tank circuit made up of Cl and it adjustable) will have a slight affect on LI is tuned to be resonant at the de- the crystal's operating frequency; you sired frequency; CI can be a variable can "zero" the crystal frequency to unit as shown; or, if you wish, a slug - within a few hundred Hz by fudging the DIRPRIRGI= COGr1sELLOR tuned unit can be used for LI. (As we adjustment of C3 (or L3). said nothing is critical; that also holds The crystal can be either a funda-

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Microcomputer memory devices LES SPINDLE*

AN IMPORTANT CONSIDERATION IN only one time and, if a programming to refresh them have been considerably planning your computer system is error is made, a new PROM has to be improved and simplified: those are now making sure that it has enough memory "burned." An EPROM (Erasable Pro- widely used. capacity to meet your needs-present grammable Read -Only Memory), how- Static RAM's, on the other hand, re- and future. The amount of data that can ever, can be erased if an error is made, quire no refreshing. They will keep be stored, and the speed with which it and the program reloaded. Even more their contents intact until the computer can be accessed, will play an important valuable is the fact that, if the program is shut off. Static memories are more role in the efficiency of the system in contained by an EPROM is no longer complex and expensive than their handling your home or business appli- needed, the IC can be erased and re- dynamic counterparts, and-generally cations. You should not only have used for a completely different purpose. -consume more power. Still, many enough memory to take care of your im- RAM, on the other hand, is designed computerists feel more comfortable mediate requirements, but also have for temporary data storage. Its contents with them than with dynamic memories. provision for expanding that memory as can be changed or read at any time and your use of the computer increases. without it a computer would be useless. Adding memory Memory comes in two basic forms. RAM is used to hold programs and data. There are several things to bear in The first is resident memory-the It is important to know that there are mind when selecting add-on memory to memory that is usually located inside two types of RAM-static and dynamic. extend your computer's capabilities. the computer and that is used to hold Dynamic RAM's are easier to design The first, of course, is whether it is programs and variables when they are and manufacture, and new large -capac- compatible with the computer. If the in use. The other form, external ity RAM IC's first appear in dynamic computer uses memory boards or memory, is used for storing programs form: the static versions follow later. cartridges, they must fit. That sounds and data. Those programs and data. Among the advantages of dynamic obvious, but is still something to watch. however, cannot be used by the com- RAM is its low power-consumption and Also, if your memory is expandable puter until they are loaded into the lower price, when compared to static simply by adding more RAM IC's, resident (or working) memory. memory. The disadvantage of dynamic make sure that they are the proper RAM is that it is "leaky," and quickly type. Finally, make sure that the new Resident memory loses its contents unless it is frequently memory does not take up physical Let's take a look at the memory refreshed. In the early days, refresh cir- space that may be needed for peripheral options available to you, beginning cuitry was quite complicated, and boards that may be added later, and that with the internal memory capacities of dynamic -memory systems were re- your computer's power supply can han- your computer. All microcomputers garded as somewhat unreliable. Cur- dle the memory plus whatever else it have a certain amount of resident rent dynamic RAM's and the IC's used may be called upon to run. memory in the form of integrated circuits, classified either as ROM (Read - Only Memory) or RAM (Random Access, or Read -And -write, Memory). Both allow the microprocessor virtually instantaneous access to the data they contain. ROM can be compared to a phonograph record-the data is fixed, and cannot be added to or subtracted from. It is used to store such things as the computer's operating system or a language (like BASIC) that will be used over and over, and which should be available to the user as soon as the computer is turned on. The ROM's that are supplied with a computer are usually designed from the ground up to contain specific data; it is, literally, built in. There are several types of ROM, though, that a computer user-with the appropriate equipment -can program himself. The first is called PROM (Programmable Read - Only Memory). It can be programmed

'Managing Editor. Interface Age magazine. FIG. 1

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The 20 MHz, dual trace oscilloscope lects lire/field triggerirg as tie time - FREE TRIAL. Return in 15 days speed s adjuslec. that would normally cost $1,000 from base for a complete refund if not someone else, now costs just $695 Service and warranty from Gould. So it's like getting part The OS300 is covered by Gould's one entirely satisfied. of it free. year warranty on parts and labor ex- 0S300 OSCILLOSCOPE How can we do it? With a special clusive of fuses, minor maintenance factory sale from us direct to you. and calibration. And can be serviced PRICE $695.00 ea.* No catches either. The 0S300 at any of Gould's more than 20 ser- provides everything you need in a vice centers across the country. QTY quality oscilloscope. Order before June 3G, 1982 and Check these features get two sets of x10 probes at no AMOUNT 20 MHz bandwidth 2 mV sensi- extra cost add applicable tivity Active TV trigger DC What could De better? Order 10 or sales tax trigger Channel sum or difference more 0S300's and you can get an INSURANCE 12 lbs. overall weight X -Y Mode even lower price of $643 per unit. Z axis input Color grouped con- How to order SHIPPING trols Triggers on frequencies up To order, simply call our toll free $6.95 ea.* to 50 MHz number, and use your MasterCard, U.S. Dollars The Gould 0S300 is a compact, VISA or American Express card. TOTAL portable 20 MHz dual trace oscillo- To order by mail, please use the scope weighing only 12 lbs. The coupon. And send your check, money scope is enclosed in a rugged metal order or purchase order. We regret housing that has a convenient carry- that we cannot accept C.O.D.'s. Name ing handle. The case size is only Call 800.321-3035 and ask for 51/2 "x 12"x 18", yet the display area operator #300 is a large, bright 8 x 10 cm rectan- Phones open Monday through Friday, Address gular CRT. 8:30 a.m. to 4:30 p.m., EST. Have your This instrument offers features MasterCard, VISA or American City usually found in more expensive Express card ready. This number is oscilloscopes including channel sum for orders only. For information, you State and difference, switched X -Y and must write to Gould Inc., Instruments across 2mV/cm sensitivity the full Division, 35129 Curtis Blvd., Eastlake, Zip bandwidth. A 2 -volt DC coupled OH 44094. Z -mod input facilitates use with logic analyzer outputs. MAIL TO: Gould Inc., Triggering facilities include AC, DC Instruments Division coupling plus an active TV synch -> G OULD 35129 Curtis Blvd. separator which automatically se- Electronics & Electrical Products Eastlake, OH 44094 CIRCLE 20 ON FREE INFORMATION CARD

www.americanradiohistory.com External storage -devices is that all the data on them is recorded first, since it is more widely used. Once you've decided about memory. serially. Just as one byte follows another Floppy disks are a sort of cross be- it's time to decide what external storage onto the tape, so do whole files. Just tween phonograph records and magnetic device you're going to use to hold your trying to locate a particular file can be a recording -tape. They come in two languages, programs, and data when time-consuming task, and updating út diameters: 51/4 inches and 8 inches and they are not resident in the computer. can be a nightmare. Cassettes are also are enclosed in a square cardboard or Audio-cassette type is the medium slow-it can take several minutes to plastic jacket to protect them (the disk that seems to be most popular (and load in a file after you've managed to surfaces are very delicate). Data is affordable) for home and hobby appli- find it! recorded as magnetic pulses on the sur- cations. Its storage capacity is high, In a business environment, you can't face of the disk. and its cost is low. A reasonably priced afford to spend time searching through The beautiful thing about disks, as ($50-$100) cassette recorder and several cassettes and waiting for them to load compared to cassettes, is that it is pos- cassettes will start you on your way. their contents into the computer's sible to find and load anything that's on Problems will quiickly arise, however, memory; you need something faster. a disk in a matter of seconds. A directory when you start trying to use cassettes The answer is a disk system. There is automatically maintained on each for larger -scale applications. are two types of disk systems: floppy disk, indicating where everything is The major disadvantage of cassettes and hard. Let's look at the floppy disk stored, and the disk drive's read/write head can position itself anywhere on the disk in milliseconds. The speed, plus the conveniences offered by the software-known as the DOS (Disk Operating System)-that controls the comings and goings of data to and from Take a good the disk, make floppy disks ideal for the kind of situations encountered in small and medium-sized business-or even in serious personal computing. It is possible to increase the storage look VACO. capacity of a disk system. Initially, it at will be probably "single -sided, single - density," which means that a 51/4 -inch disk will be able to hold approximately 90 kilobytes (the figure will vary depending on the design of the circuit that continued on page 99 Power Line Filters

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www.americanradiohistory.com STATE OF SOLID STATE

One IC voltage conversion

ROBERT F. SCOTT, SEMICONDUCTOR EDITOR

WHILE EXPERIMENTING WITH SOLID - state circuits, have you ever wished _ Ì t'B that you could power analog circuits I 1 1 - 1 from the supply you are using for digital circuits? Well, it's not impossible. In LCD DISPLAY DISPLAY use the In- LINES fact, it's simple when you 1+1 5V) tersil CMOS ICL7660 voltage converter 81y 400µA 220µA 60µA 50µA connected as shown in Fig. 1. Apply a 730µA 27K 8 3 36 positive voltage between pins and +;0µF ICI 10µF and you'll get a negative voltage of the t I4 ICL- 4.72 1.5V 7660 5 IC2 same value between pins 5 and 3. Both 4.7 100K BATTERY. -- ICL 1MEG voltages are measured with respect to IC3 31 7660 5 IC L- WN. (0V) pin 3, which is ground or the negative '4'D2 7126 terminal of the battery or driving power ICL 30.1%0.01 8069 supply. 32 \ -1.5V) D1 .1.10µF 1N4148 26 (-4.5V) +5V VIN IN

FIG. 3 2 -5V OUT 10µF ICL7660 , is useful when the load on a single 7660 5 is four times the battery voltage, or 6 11OUT 40mA 4 > causes an excessive voltage drop. volts. That is high enough to supply the 10µF* Normally, simple power supplies 7176 A/D converter and the 8069 volt- 1 cannot be paralleled with any degree of age reference. The external voltage ref- efficiency because the output voltages erence is needed because the A/D con-

FIG. 1 and internal impedances of the inverter's internal reference works best dividual sources are never precisely with a power supply of over 6.5 volts. +5V IN equal. Thus, when two such supplies The 1.2 -volt external reference insures are paralleled, the one with the higher that the A/D converter will work cor- output will carry most of the load. In rectly even when the battery voltage is Fig. 2, device sees the same input low. ICL 7660 each 10µF 1 3 voltage and, since conversion efficiency Total battery drain is typically only .71 4 is nearly ideal, the devices share the 750 MA. Battery voltages up to 3.5 may 1/4 CD4077 load equally. be used. Diode D1 should be used 1K Each device has a separate "pump" whenever battery voltage can be ex- capacitor (10 F in this application). pected to exceed 3 volts. The CD4077 exclusive NOR gate com- The ICL7660 is an inexpensive solu- pares the device outputs at pin 2 and tion to many voltage -conversion prob- ICL 7660 7 -5V clocks one to maintain sync with the lems. It's only $1.95 in lots of 100. Your OUT oscillator in the other. The scheme can Intersil distributor or favorite mail- be extended to deliver around 160 mA order supply house should have it in 20µF by paralleling four devices and using an stock. extra logic gate. In an interesting circuit innovation VMOS power devices FIG. 2 described by Intersil. a 1.5 -volt cell and Field-effect transistors (FET's) have Thus, in the 7660, we have a unique a pair of 7660's were used as cascaded been around as practical devices since device that converts a positive -input voltage doublers to deliver 6 -volts DC about 1952. But for the next twenty voltage to a negative -output voltage to a 7126 31/2 -digit micropower analog/ years or so. they were strictly low - with a conversion efficiency of 98cvc digital converter driving a liquid -crystal power devices capable of handling only less 1 watt. Thus, they when RL = x . Power -conversion ef- display. The circuit is shown in Fig. 3. loads of than ficiency is 989 when RL is 5000 ohms. With 1.5 volts applied to the input of were not able to compete with bipolar Output current is greater than 40 mA ICI, the first voltage converter, a nega- transistors and SCR's in power -han- into a 55 -ohm load. tive 1.5 volts is developed at pin 5. dling applications. The reason for that If you need a higher supply voltage Converter IC2 sees a total of 3 volts at is that in a typical FET, the current for a portion of your circuitry, simply its input (1.5 volts from the battery and travels horizontally, just below the sur- cascade two or more 7660's. Need 1.5 volts from ICI) and produces -3 face of the chip, and the maximum cur- more current? Connect two 7660's in volts with respect to the output of ICI. rent density is much lower than that of parallel as shown in Fig. 2. That circuit The total voltage across IC2 pins 8 and continued on page 97

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VERSATILE LABORATORY POWER SUP- AMATEUR MICROWAVE RECEIVER SYS- PLY delivers a fully regulated output from TEM 36" Parabolic antenna, receives 2.1- 0 to 30 VDC at 0 to 2A. Ripple and noise is 2.5 GHz with over 55 db system gain, YES, 300 Watts RMS... build this "BRUTE" less than 250 uV RMS. Model 3002A fea- $199.95. REPAIR, we repair all makes of amp easily with our special HEATSINK tures continuously adjustable current communications equipment, including and PCB kit ... complete with instructions limiting and precision constant voltage/ amateur microwave. Large line of elec- ... only $24.95 US/PPD. For fast delivery, constant current operation with -auto- tronic kits and parts. Send $2.00 for cata- send a cashier's check or money order only matic crossover." Unit can also be used log, refundable on first purchase. VISA & NO COD PLEASE, to: DACOR LIMITED, as a current regulated power source. Only MASTERCARD ACCEPTED. SRS PO BOX P.O. Box 683, Station Q, Toronto, CANADA $119.95. Electro Industries, 4201 W. Irving 50, East Detroit, IMI 48021 (313) 791-5551. M4T 2N5. Park Rd., Chicago. IL 60641, (312) 736-0999. CIRCLE 12 ON FREE INFORMATION CARD CIRCLE 8 ON FREE INFORMATION CARD CIRCLE 13 ON FREE INFORMATION CARD

www.americanradiohistory.com Troubleshooting IC circuits JACK DARR, SERVICE EDITOR

INTEGRATED CIRCUITS ARE STRANGE components before condemning the IC, results and the trouble is still present. and mysterious things to many of us. though! Some sets use the audio- look for pins with only a bypass capaci- However, as times change, so must we; preamp driver IC as a volume control- tor, or something else, on them. If you and because IC's appear to be with us its output level is determined by a see a signal on ahy pin with a bypass to stay, we're going to have to learn to variable control -voltage. Make sure capacitor, the capacitor is very likely troubleshoot the circuits they appear that the control voltage is normal, and open. Also, the 3.58 -MHz reference - in. The question is: How do you trouble- varies as it should when the volume oscillator signal is often brought out to shoot something that looks like a black control is turned. an external tint -control; check all the bug with 24 legs? components in that circuit, too. Open The answer is to determine what the or leaky capacitors can cause feedback function of the IC is supposed to be, and some very strange symptoms! and then to see whether it is doing what Troubleshooting circuits containing it's supposed to. Check the inputs and IC's is really very simple: Any circuit J .0% vel the outputs. If it's a demodulator, is it has an input and an output. If signal is demodulating? If it's an amplifier, is it OK on the input, but not on the output. amplifying? And so on... and all the external parts are good, then Taking a comparatively simple de- there's nothing left between those two vice, an audio-preamp driver IC, we FIG. points but the IC. should see low-level audio signals at the input, and the same signals, at a much higher level, at the output. The output drives the base of the audio -output transistor. (Some IC's have the output transistor built in, in which case they drive the -\ BLANKING speaker directly.) To test PULSE the IC, feed a low-level-about one - a b volt peak-to-peak-audio signal to the input. Then, check for the normal FIG 2 signal -level at the output. That can be We can still use the same basic tests If the problem is intermittent, don't as simple as listening for it. If you don't with a much more complex but basically ignore the IC's when you're hunting for hear anything, scope the output of the similar type of IC, such as a color de- it! IC's can develop thermal intermittents IC. If there's a signal there, the output modulator. Feed a known input -signal just like other components. In one transistor isn't working; check it. Input to the IC and check its three outputs (in situation that came up some time ago and output pins of an IC, as well as this case) to see whether or not there's (and has cropped up several times since) normal signal -levels, can usually be a signal present at each. The input signal the 3.58 -MHz reference signal of a well- found on the schematic of the device can be the video output of a color -bar known riiake of receiver dropped out giving you trouble. generator, and will show a "comb" intermittently. The oscillator was made If there's no output from the IC, pattern (see Fig. 1). Use your scope to up of a simple op -amp and a crystal. check the DC voltages around it, starting set the input level indicated on the The IC would get hot, and the signal with the DC -supply pin. It is connected schematic. The three outputs should would disappear. (By the way, the best to the DC power -supply, usually through bear the familiar "lazy -S", or "rocker" cure we fóund for that was to use an IC a dropping resistor. If the voltage is off, shape shown in Fig. 2. Each output of a different make from the original! check the resistor, and any bypass feeds the input of one of the three color - Sylvania. bE, and RCA all had exact capacitors that may be connected to the amplifier transistors. Your schematic substitute§ for it.) power -supply pin. If the resistor shows should indicate the correct peak -to - Audio distortion showed up in a signs of overheating, you may have peak voltage for each IC output. small black -and -white set that had an found the problem. The chances are Normally, the red and blue outputs will audio IC with a built-in output transis- that the IC is internally shorted, or a be stronger than the green one. tor. Codlihk the IC cleared up the dis- bypass capacitor is bad. If the supply If you see an input but no output, tortion, so the IC was replaced. Unfor- voltage is present but incorrect, check read all of the DC voltages developed tunately, the same symptoms showed all the other pins of the IC. Some may on the IC pins. If one pin is supposed to up with the new one! The final "fix" have no connection, or go directly to have +3.6 -volts DC, for example, with was to cement a small heat sink, made another IC, but others may have small a small resistor to ground, and the re- of a shallow U-shaped piece of thin resistors to ground, or capacitors, on sistor is OK but the voltage is missing, aluminum, to the IC case. That kept it them; check them out, and make sure the IC may be bad. Check DC voltages cool enough so that it didn't act up. that the DC voltages are correct. They at other pins; you may find more of Replacements for some "unknown" are produced by the IC and, if one or them off, and if that's the case, it's a IC's are hard to find, especially in the more is not there, the IC is probably good sign that the IC is bad. case of some of the imports. Sometimes bad. Be sure to check all the external If the DC -voltage tests don't produce we have been able to find a substitute

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Design of Digital Systems - six volumes Thanks very much Douglas! That's the kind feedback a us ADVANCED COURSE BASIC COURSE NO RISK GUARANTEE of field lot of DESIGN OF DIGITAL SYSTEMS There's absolutely no risk to you. If you're need. not completely satisfied with your courses, Six largolarmaf volumes - esoh 11'/. a 81/4". Digital Computer Logic and simply return them to CLI within 30 days. CONTENTS Ekctrortics We'll send you a full refund, plus return post- The contents of Design of Digital Sys- age. NO HIGH -VOLTAGE tems include: Book 1: Octal, hexadecimal and binary TAX DEDUCTIBLE number representation of nega - This RCA CTC-81 has no raster and systems; In most the lull cost of CLI live numbers; complementary systems; cases, courses be a tax deductible expense. binary multiplication and division. can noise in the sound. I've got DC voltage on Book 2: OR and AND functions; logic 8i gates; NOT, exclusive-OR, NAND. NOR and PHONE ORDERS - FREE T402 (the driver transformer for the trace exclusive - NOR functions; multiple input To order by phone, call (617) 664-3857 gates; truth tables; DeMorgan's Laws: Digital Computer Digital Computa with your credit card information. It won't switch) and there is a gate pulse on the canonical forms; logic conventions; Kar- Logic and cost you a dime, because we'll deduct the mapping; -state and wired Lie are naugh three Mectrorics cost of your call from the price of the courses retrace switch, but no waveforms on the log lc: you order. Book 3: Half adders and full adders; sub - transformer! Sometimes the set will kick tractors; serial and parallel adders; processors and arithmetic logic units (ALUs); TO ORDER BY MAIL on and play; when that happens, every- multiplication and division systems. You may use the order form below If yo. Book 4: Flip-flops: shift registers; o wish, but you don't need to. Just send your thing tests out normal! I need advice!- asynchronous counters; ring, Johnson and check or money order (payable to Cam- exclusive -OR feedback counter; random bridge Learning Inc. to the address below. If G.K., Massillion, OH access memories (RAMS); read-only you don't use the order form, make sure your memories (ROMs). Digital Computer Logic 8 Electronics address is on your check or the envelope, From the reaction when the fault is Book 5: Structure of calculators; key- and write "DOS" (Design of Digital Sys- board encoding; decoding display data; tems). "DOLE" (Digital Computer Logic 8 present, it sounds as if the retrace register systems; control unit: program CONTENTS Electronics), or "both" (both courses) on ROM; address decoding; instruction sets; Digital Computer Logic and Electronics your check. switch isn't doing anything-it could be instruction decoding; control program is designed for the beginner. No mathe- Mass. Residents add 5% sales tax. We pay structure. matical knowledge other than simple arith- all shipping costs. open, and also apparently intermittent! Book 6: Central processing unit (CPU); metic is assumed, though you should have We also accept company purchase or- memory organization; character represen- an aptitude for logical thought. It consists ders. Try checking it. or changing it. If it tation; program storage; address modes; of 4 volumes - each 11W" x 81/4" - and input/output systems; program interrupts; serves as an introduction to the subject of AIR MAIL were shorting, it would blow the fuse: interrupt priorities programming; assem- digital electronics. blers; executive programs, operating Contents include: Binary, octal and The prices shown include surface mail but if In Air mall post- it's open, you'd get exactly what systems, and time-sharing. decimal number systems; conversion be- postage anywhere the world. age costs en extra for both courses (10 tween number systems; AND. OR, NOR $10 you see. volumes) . OUR CUSTOMERS and NAND gates and inverters; Boolean Design of Digital Systems has been algebra and truth tables; DeMorgan's (Feedback: You were right-the re- bought by more than half the 50 largest Laws; design of logical circuits using NOR DISCOUNTS corporations in America, and by Motorola, gates; R -S and J -K flip-flops; binary Call or write for details of educational and trace switch was open. Thanks.) Intel, DEC, National Semiconductor, Fair- counters, shift registers and half -adders. quantity discounts, and for dealer costs. child, General Instrument, Hewlett- Packard, Heath Co.. M.IT. NASA, Smith- sonian Institute, Bell Telephone Labs. And SAVE $5 NO HORIZONTAL SWEEP many, many more, as well as corporations If you order both courses, you save $5. Order individuals in over 50 countries. al no obligation today. and A Sony TV -740 came in with just a verti- Tee CembfMga Looming Inc., 1 Judith Drioo, North Raedtrrg, MA 01804 cal line in the center of the screen. The CAMBRIDGE Please send me - Order free by phone LEARNING Inc. sets of Design of Digital Systems $19.95 solution seemed easy-find the break in ' Mastercharge/VISA sets of Digital Computer Logic 8 Electronics $14.95 1 Judith Drive the yoke circuit. It turns out that C810, North Reading, sets of both courses $29.90 No MA 01864 shipping charges Enrior 4 m rbmir many Order (payabro to Cambridge Learning inc.) for total 3.5 µF, was open. Since I didn't have an Money -back guarantee NAME exact replacement, I used a 3.0µF, 500 - Call (617) 664-3657 to ' Tax deductible order by phone-free. ADDRESS ... volt -DC capacitor and a 0.47µF, 100 - ' Save S5 CITY/STATE/ZIP RIO 7 days. 24 hours continued on page 98

96 CIRCLE 40 ON FREE INFORMATION CARD

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STATE OF SOLID STATE 15MHz DUAL TRACE PORTABLE OSCILLOSCOPE continued from page 9/ GETTO THE a bipolar device that uses vertical cur- PORTABLE rent flow. CORE OF Soar Corp's new Model MS -3015 Around 5 years ago, a new FET technology was developed to increase the YOUR APPLE® small scope (4% x 8% x 1 13/4) comes current density of the devices. That in complete with FOUR operating power turn, led to the development of high - Sams wants to introduce choices built-in! power FET's that feature both high - you to the syntax and 1. Internal NiCad batteries and auto voltage and high -current capability. programming techniques of re -charge system. The technological improvement on the Applesoft with APPLESOFT LANGUAGE, a complete, 2. AC 90 to 130V, basic MOSFET, Vertical MOS or VMOS (also called V -groove MOS) easy -to -understand handbook written in a self -teaching 3. AC 180V to 260V all at 48 to owes its greatly improved characteristics 440 Hz and format. Several ready -to -use and high -power capability to a "V" programs are included which 4. external DC 11V to 30V (runs on groove channel that promotes vertical demonstrate most of the your car/boat battery). current flow. concepts covered. APPLES INTERFACING from the popular Bla ksburg group SOURCE GATE SOURCE helps you ui derstand the Si02 important tásk of successfully interfacing ,our Apple to a variety of peripheral devices. Experiments are included to pew Y//i:' %í11,i%i. I illustrate Apple interfacing fundamentals. Order both from Sams today and save more than 15%! N+ SUBSTRATE//

MODEL 3015 DRAIN

FIG. 4

Figure 4 shows a cross section of a VMOS channel. The device is fabricated VERSATILE on an n+ substrate that becomes the drain and provides a low -resistance

Dual Trace DC to 1 5MHz with sen- current path. An n- epitaxial layer is sitivity of 2mV to 10V/Div on 12 added to increase the drain -to-source ranges, your choice of 5 operating breakdown voltage and to reduce feed- modes, plus X -Y, add, subtract. 19 back capacitance. Lightly doped p- bodies are diffused sweep ranges from 0.5 µ sec thru into the epitaxial layer to form channel 0.5 sec. with X5 mag. choice of four regions. Smaller n+ regions are dif- - trigger modes plus Auto Free run fused into the p- island to form source -- and preset TV/H. 3.7" rect. CRT regions. The n- epitaxial layer and with internal graticle. Comes com- substrate now become drain regions. SAMS plete with two 10:1 probes, detach- The V-shaped groove is etched i BOOKS able 3 conductor AC cord. FULL through the source and channel regions TM ONE YEAR LTD. WARRANTY. into the epitaxial layer. A silicon oxide APPLESOFT LANGUAGE, No. 21811, $10.95 layer is then grown on the surface and in APPLE" INTERFACING No. 21862, $10.95 Set of both books. No. 21962 $17.95 the groove and then aluminum metalliza- Amount of Order $ tion is added to form source and gate Add local salts tax where applicable $ AFFORDABLE connections. Finally, the entire chip is Add Handling Costs $ 2.00 passivated (coated with an inert protec- Total Amount of Order $ tive material) to keep contaminants Check Money Order VISA Quantities of: MasterCard (InterFank No from entering the gate material. Account No Expiration Date 1-9 $749.00 each The vertical design of the VMOS Full payment by check, money order, or charge card 10 £t up 675.00 each technology gives it the following ad- must accompany your order. vantages over the conventional MOS Name (print) Available at selected distributors or structure: Signature Address write/phone: 1. The length of the current channel City State Zip is determined by the depth of the Call 800-428-3696 317-298-5566 for the I diffusion-a much more easily toll-free, or NORTH /r SOAR name of your local Sams Book outlet or to order by controlled factor than mask phone (give Sams Operator the code number in the `l.Urporation I AMERI(:ANi spacings used to define channel box below). Offer good in USA only and expires 8/31/82. Prices subject to change without notice. 1 126 Cornell Avenue Cherry Hill, NJ 08002 lengths in conventional MOS. AD 1841 Tel. 16091 488-1060 That makes it possible to obtain a better width/length ratio and al -

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www.americanradiohistory.com Electronic Troubleshooting lows higher current densities to be obtained. 2. Each groove creates two parallel channels so the current density is FREE WINNER inherently doubled. 3. The substrate forms the drain contact so that there is no need to provide space for a metal drain contact on top of the chip. That reduces chip area and thus keeps saturation resistance low. 4. The high -current density results in low gate -to -drain (feedback) capacitance because the portion of the gate nearest the drain L.E.D.s (called the overlap) is in the bottom of the V groove. In a conven- A $2.00 VALUE tional MOSFET, extra drain -gate You can now receive ten prime T-13/4 or overlap must be provided to T-1 red LEDs absolutely free. ltis our way of allow for possible mask misalign- introducing you to the quality parts we of- ment. Tht increases the gate -to - fer. drain and gate -to -source capacitances. IOing°1 5. The epitaxial layer of the VFET is lightly doped so it absorbs the Hickok's MX333 with 14803 NE 40th Dept. RE052 depletion area from the reverse - Redmond, WA 98052 VARI -PITCH® and LOG l-TRAK" biased drain -to -body PN diode. That greatly increases the break- Yes, Please send me 10 Free LEDs, plus down voltage while having little your brochures on additional products available. I prefer T-1 T-13/4. Instantaneous VARI -PITCH speeds: or no effect on other device parameters. Various designs of VMOS transistors NAME Voltage tracing have been developed by different ADDRESS Troubleshooting in hard -to - manufacturers to increase such param- CITY- __. ST ZIP_. reach locations eters as speed, power -handling capacity. Please Include $1.00 to help cover postage and and voltage and current ratings. Names handling. Tuning type adjustments given those technologies include DMOS. VDMOS. TMOS, ZMOS. CIRCLE 54 ON FREE INFORMATION CARD Resistance checks HEXFET and SuperFet. We'll get to them in a future column. R -E Put Professional Knowledge and a Digital logic troubleshooting COLLEGE DEGREE And . . . Detects signal charac- SERVICE QUESTIONS in your Electronics Career through teristics and abnormalities not pos- contiimed from page 96 sible with digital or analog meters.

volt -DC one in parallel. That caused LO G I -T R A K replaces the best more problems! Now the sweep stops 100MHz logic probes and offers: about 11/2 inches from the right, with bad foldover. Everything around the yoke Eyes on probe the tip, HI/LO checks out OK. Any ideas?-G.H., indication Alplaus, NY You had the right idea, Instant identification of margi- but the wrong part! Since that capacitor is in the nal states and fault conditions horizontal circuit, the original must have DEGREE 100MHz response been a special type, with a special No commuting to class. Study at your dielectric made to withstand the high - own pace, while continuing frequency pulses (like the familiar 4- your present 5n sec pulse detection legged capacitors). job. Learn from easy -to -understand lessons, You'll probably have to get an exact with help from your home -study instructors LISTEN to what the MX333 can duplicate. Sony's address is Sony whenever you need it. do for you. Ask about our NO Corp. of America. 8281 N.W. 107th In the Grantham electronics program, RISK 30 day Free Trial. Terrace, Kansas City, MO 64195. Look you first earn your A.S.E.T. degree, and up the New York State distributor and then your B.S.E.T. These degrees are ac- try him, too. credited by the Accrediting Commission of the National Home Study Council. HICKOK HIGH -VOLTAGE PROBLEM the value innovator Our free bulletin gives full details of I wrote you recently about a HV the home -study program, the degrees problem in an RCA CTC-68. One of the awarded, and the requirements for each things you suggested was the HV -regu- degree. Write for Bulletin R-82. THE HICKOK ELECTRICAL INSTRUMENT CO. lator transformer. That was it! The 10514 Dupont Avenue Cleveland, Ohio 44108 Grantham College of Engineering [216] 541-8060 solder joints were bad. Thanks. Thanks to Jim L. Webb, Fox, OK, for 2500 So. LaCienega Blvd. the feedback. R -E Los Angeles, California 90034 98 CIRCLE 48 ON FREE INFORMATION CARD

www.americanradiohistory.com disks are usually found in elaborate Get A GNOME COMPUTER CORNER business systems. the original micro -synthesizer A recent-and more affordable- continued from page 90 Every day more people discover that PAIA's hard-disk system appeared several GNOME is the most versatile, cost effective years ago and is rapidly finding popu- special effects cevice on the market today. controls the disk drive) and an eight - in the microcomputer market. John Simonton's time -proven design larity provides two envelope generators, VCA, VCO inch one about 250 kilobytes. The Winchester -technology disk and VCF in a l w cost, easy to use package. Changing the disk -controller board ("Winchester" was its code name Use alone with it's built in ribbon controller or can allow you to have twice the capacity when it was under development) typi- modify to use with guitar, electronic piano, polytonic keyboards, etc. on the same disk and drive you have cally uses 8- or 51/4 -inch platters to give The perfect in soduction to electronic music been using by going to a double density capacities starting with several mega- and best of all, the Gnome is only $69.95 in format. In that format, the amount of bytes and going up. Winchester drives easy to assembi kit form. Is it any wonder why we've sold thousands'? data that can be stored on one side of a are now available that can fit in the single disk is doubled. same space previously occupied by a The latest in floppy -disk technology standard 51/4 -inch floppy -disk drive, but is quad density, or double -sided, provide many times more storage ca- double -density. There, two read/write pacity. (A representative Winchester - heads are used, one for each side of the technology system with floppy -disk disk. and a single eight -inch disk can backup is shown to the left of the com- hold up to a megabyte of data. puter in Fig. I.) Prices start out around Most disk systems can be expanded $3000.00, but, when all the factors are by adding extra drives. They usually considered, that is not a big price to pay extensive use come set for single -sided, single density if you are going to make CHARGE TO \ lSA OR MC TOLL- FREE but many can be reconfigured the system. operation, of 1-800-654-8"057 9AM to 5PM CST MON-FRI to take advantage of the more advanced The memory market-both resident DIRECT INQUIRIES recording techniques. and external-offers a staggering variety Tt) Beyond floppy disks are hard disks. of choices. Those choices involve not RNA Electronics, Inc. They are usually aluminum platters only the medium, but also the quality of Deo1.5R.1020 W. Wilshire 6v. Oklahoma City. 06 73116 (405)843-9626 coated with a metallic oxide and they the product. It's a good idea to consult Send GNOME MICRO- SYNTHESIZER rotate at very high speeds. Because of other computer users and to search Kit ($69.95 plus $3.00 postage/ the high speeds involved, the read/write through the ads, catalogs, and com- Send FREE CATALOG head, unlike that of floppy -disk sys- puter stores before making a decision. name tems, does not touch the disk, but floats A computer cannot perform efficiently address very close to its surface on a cushion of if it doesn't have sufficient memory. Lcity state zip air. Hard -disk capacities start at 5 What it doesn't need, though, is pre- J megabytes and go on from there. Hard mature senility. R -E CIRCLE 52 ON FREE INFORMATION CARD

H A M E PRESENTS NEW HM 203 High performance at low cost. $580 (PROBES INCLUDED)

A quality scope, made in the U.S.A., by a company with over 23 years experiience.

Hameg introduces high performance at low cost in the HM 203, a full featured, highly reliable, dual trace HA MEG 20 MHz oscilloscope. For only 8580, the HM 203 has specifications normally associated with higher priced 88-90 Harbor Rd.

scopes. Bandwidth - DC -+20 MHz Risetime 17.5 ns Overshoot 1% max. Y amp range 5 my/cm to Port Washington, N.Y 11050 20 v/cm Max. input voltage 500V Timebase .5 s/cm to .2s /cm Sweep mag. x5 Trigger 5 Hz to Tek (516) 883-3837 MHz X:Y plot Built-in probe more. Its lbs.) 30 calibrator and sturdy construction and light weight 113.2 D make the HM 203 equally at home in the field and on the test bench. c0 Nm CIRCLE 38 ON FREE INFORMATION CARD 99

www.americanradiohistory.com

For more details use the free information card inside the back cover. Digital DESKTOP COMPUTER, the Advantage, is reduction of distortion over a conven- Multimeter the first completely integrated desktop tional bi -radial (elliptical) stylus. Its low stand-alone system to offer minicomputer - mass allows the stylus assembly to follow The Drake DM2350 Digital Multimeter is a grade graphics capabilities. It includes a the record groove not only up to, but convenient, small handheld liquid crystal 12 -inch display, two 51/4 -inch high -capacity beyond, the theoretical cutting velocities display meter ideal for the serviceman or hobbyist. This 31/2 digit meter is auto -ranging, of today's recordings. The "HE" stylus as- auto -zeroing, has polarity indication, and an sembly also incorporates a telescoped over -range warning signal. Battery life is stylus -shank structure for reduced effec- greater than 300 hours with a "low battery" tive mass, without sacrificing stiffness. indicator. A continuity test sounds a signal when circuit resistance is less than 20 ohms. Installation of the model MV3OHE simply Dc accuracy is a basic 0.8%. requires plugging the carrier arm into the Batteries, probes, 20 amp current shunt, spare tone -arm pivot of a turntable. The inte- fuse and soft carrying case all included at $95.95 grated design eliminates the nuts, screws, Add $2.50 shipping and handling per order. and terminal -pin wires usually needed to Send check with order and provide street address mount phono cartridges. The model for UPS shipment. Ohio residents add Sales Tax. CIRCLE 131 ON FREE INFORMATION CARD MV3OHE has a suggested retail price of Charge card buyers may call toll free: $230.00.-Shure Brothers Incorporated, 1.800.543.5612 floppy -disk drives, an 87 -key Selectric- 222 Hartrey Avenue, Evanston, IL 60624. for In Ohio, or style keyboard, and a choice of optional DRAle information call: 45) 1-513-866-2421 broad -ranging operations and applications software. MICROPHONE, model PL88, is a dynamic R. L. DRAKE COMPANY The Advantage is built around a 4 -MHz cardioid vocal microphone, featuring 540 Richard Street, Miamisburg, Ohio 45342 Z80A and includes 64 kilobytes of random- voice -tailored frequency -response char- INSTITUTIONAL AND DEALER INDUIRIES INVITED. access memory (RAM). It features a 12 - CIRCLE 51 ON FREE INFORMATION CARD inch bit -mapped CRT display to produce bar charts, pie diagrams, plotted graphics, and 3 -dimensional visuals, driven by an additional 20 kilobytes of RAM that support the bit -mapping feature. With the Ad- vantage, small-business computer owners will be able to integrate graphics into their everyday business without paying a premium. The Advantage is priced at $3999.00.-North Star Computers, Inc., 14440 Catalina Street, San Leandro, CA 94577.

In general, spring reverbs don't have the PHONO CARTRIDGE, model MV3OHE, is best reputation in the world. Their bassy designed excusively for model SME 3009 "twang" is only a rough approximation of Series and model SME ll/S CIRCLE 133 ON FREE INFORMATION CARD natural room acoustics. That's a pity because Ill 3009 Series it means that many people will dismiss this tone arms. It is a high-performance, minia- exceptional product as "just another spring ture cartridge that is integrated with an acteristics; it is resistant to handling - reverb". And it's not. In this extraordinary SME carrier -arm. The integrated design noise. Designed for the vocalist on a tight design Craig Anderton uses double springs, results in significantly reduced effective budget who is unwilling to compromise but much more importantly "hot rod's" the mass; it virtually eliminates headshell his or her standards of quality, the model transducers so that the muddy sound typical resonances, and provides easy -to -mount PL88 features an on/off switch and, for most of springs is replaced with the bright convenience. additional flexibility, is available in both clarity associated with expensive studio model MV3OHE plate systems. The features a distor- high- and low -impedance models. The model PL88 is Kit consists of circuit board. instructions. tion -reducing hyperelliptical stylus, the priced at under $70.00.- all electronic parts and two reverb spring tip of which provides as much as a 25% Electro-Voice, Inc., 600 Cecil Street, units. User must provide power lf9to15v) Buchanan, MI 49107. and mounting (reverb units are typically mounted away from the consolel. CHARGE TO VISA OR MC TOLL-FREE STEREO CASSETTE DECK, model KX-70, 1-800-654-8657 9AM to 5PM CST MON-FRI uses metal tape and has an exclusive memory that V) DIRECT INQUIRIES TO computerized provides fast, automatic program access, as well as re- Z MA Electronics, Inc. peat operation. 0801.5 AR 1020 W. Wilshire 8v. Oklahoma City. OK 7311614051843-9626 cc Called the Direct Program Search Sys- x tem (DPSS), the microprocessor -con- Ú 1 I I Send the 6740 REVERB KIT $59.95 plus -I w shipping (s3) enclosed or charged. trolled memory expands the deck's nor- to w I I I Send Free Catalog mal functions include fast -forward and Q I name I rewind search of up to 15 music selec- CIRCLE 132 ON FREE INFORMATION CARD tions on each side, as well as single-selec- I address cc 1city state zip J 100 CIRCLE 53 ON FREE INFORMATION CARD www.americanradiohistory.com channels, also delayed by .03 seconds. In most recordings, the extreme low - ®3LW Audio frequency signals are cut in mono; thus the difference signal tends to be bass-shy. To fill in the missing bass, a mono signal made up of the sum of the left and right Modules front is CIRCLE 134 ON FREE INFORMATION CARD channels added to the rear speaker at frequencies below 60 Hz. High fre- tion and full -side repeat and re-record/ quencies are contoured for the side and MOSFET standby. The DPSS is easy to operate and rear speakers as they would be in the concert hall. A remote -control unit with a - features a multicolored LED display and 25 Power lighted arrows as mode indicators. foot cord permits sound levels for the Electronic full -logic controls give in- front, side. and rear speakers to be ad- from a Amplifiers stant response at the touch of a button, justed distance. and allow the listener to change modes BUILT-IN HEATSINKS ONLY 5 CONNECTIONS without an intervening "stop" action, and REQUIRED 5 YEAR WARRANTY without tape stretch. Operation is simpli- Choose ILP MOSFET power amps when you need the ur fied further by smooth -action pocket most in performance without spending big money. They 1111 provide the fastest possible slew rale, low distortion at loading, and the pocket is removable for high frequencies, + better thermal stability. MOSFET power amps work with complex loads without difficulty easy head -cleaning and demagnetizing. A and without crossover distortion. Three models are available. with integral heatsink to mount on your own dual -motor system insures minimal wow chassis (optional rack mount cabinet available). Con- and flutter, and provides fast handling of CIRCLE 136 ON FREE INFORMATION CARD nection is simple - via 5 pins. MOSFET5 can be com. bined with other ILP modules to create almost any audio the tape. system, whatever your age or experience. Ulira.fi specifications. Slew rate 20Vus. Rise time 3 us. Other features include Dolby noise -re- The model ARU allows the user to take SIN ratio 100 db. Frequency response (-3 db) 15 Hz - 100 kHz. THD (Typical at 1kHz) C 0.005%. IMD (50Hzl7kHz duction; a newly developed amorphous - charge of his total music system far more 4,1) <0.006%. alloy magnetic head for optimum metal - easily than any other system of its kind MOS12080W14-8a(re uires ± 45V) $79.95 MOS2001213W/4-8í1(r quires ± 55V) $129.95 tape performance; three tape -selector because all key functions are available MOS400240W1411 (requires ±55V) $199.95 positions with automatic equalization and through the remote -control section. It will WRITE FOR FREE CATALOGUE LISTING; bias -matching; seven -LED peak -level function with any stereo system the user BIPOLAR POWE AMPLIFIERS' HIFI PREAMPS MIXERS 'POW =R SUPPLY UNITS 'CABINETS meters; a timer/standby switch; single - now has, and with any kind of music, as GUITA- PREAMP and more operation recording; MIC mixing; auto- well as interface with virtually anything the matic jacks, and a headphone jack. The user might acquire in the future. The model KX-70 has a suggested retail price model ARU is priced at $829.00.-Bench- GLaDSTOIRE of $349.00.-Kenwood Electronics, mark Electronics 901 Fuhrmann Blvd., Buffalo, NY, 14203 Dept. Acoustics, 201 West 89th Street, CALL (716) 849.0735 to order. Have your P., 1315 E. Watsoncenter Road. Carson, New York. NY 10024. VISA or MasterCard ready. For information CA 90745. call (416) 787-1448 or circle reader number. Dealer/OEM erquiries (416) 787-1488. In Canada. Gladstone Electronics. Toronto. CORDLESS TELEPHONE, model FF-4000, is microprocessor -based; the user can SPEAKERS, model Micro 10, are 131/2 x CIRCLE 59 ON FREE INFORMATION CARD 91 x 91/2 inches, and have cabinets made from American black walnut. They feature Z/\8I $159.

CIRCLE 135 ON FREE INFORMATION CARD new 61/2 -inch modified polypropylene woofers with 11/4 -inch high -temperature aluminum voice -coils; leaf tweeters, cases lined with lead, and hand -rubbed oiled walnut cabinets. The model Micro 10 is G priced at $500.00 a pair.-Soundmates, Memotech 64K Memopak 796 29th Avenue S.E., Minneapolis, MN The Memopak is a e4K RAM pack which extends the memory of the 2X81 by a further 56K. Design- 55414. JPVGß CB ed to be in the price range expected by Sinclair owners. Plugs directly into the back of the ZX81 tC,)eG . CB standard and does not inhibit the use of the printer or other 2 meter add-on boards. There is no need for additional power supply or cables. The Memopack together AMBIENCE ACCESS SYSTEM, model Scanners with the ZX81 gives a full 64K. which is neither ARU, offers a unique time Amateur Bands switched nor paged. and is directly addressable. -delay system The unit is user transparent, and accepts such that adds nothing of its own to sound re- e General Communication basic commands such as 10DIM A(9000). . With the Memopak extension the ZX81 is production. The listener receives the am- Industry transformed into a powerful computer, suitable for bience that is present in the recording; Marine VHF business, leisure and educational use, at a frac- tion of the cost of comparable systems. there is no extra reverberation, and the Micro processor crystals effect is that of being in the concert hall. Send 10, for our latest catalog. Write or The original signal is transmitted without phone for more details. modification to the front speakers, while maDsronE easy Electronics, 901 Fuhrmann Blvd.. Buffalo. NY the same signal is fed to the side speakers, to 14203. JAN charge Call 849.0735 to order. Have with a time delay of .03 seconds. In addi- 1716) your VISA or MASTERCARD ready. $3.00 shipping and D tion, a pair of rear speakers receives an P.O. Box 06017 handling. { In Canada. call (416) 787-1448. Ft. Myers, F uncorrelated signal that consists of the orlda 33906 Mail orders send check or money order. Sorry between all phones (813) 936.2397 no CODs. Circle reader service card for w difference left and right front Sinclair software catalogue. Iv

CIRCLE 57 ON FREE INFORMATION CARD CIRCLE 60 ON FREE INFORMATION CARD 101

www.americanradiohistory.com choose rotary pulse or pure tone -activated hours. There is also a re -dial button, which dialing, making this the first cordless tele- permits one -button re -dialing of the last phone capable of full central -telephone - number called: a "battery -low' light, equipment interface. Features offered by which indicates when the handset is in the phone company such as call waiting, need of recharging: a "charge" light on call forwarding, three-way calling, and the base, which indicates that the hand- speed calling can be used, via a special set's batteries are being recharged, and a "hook" key. "power" light on the base to indicate that The model FF-4000 has automatic dial- power to the base station is on. Other fea- ing capability, which means that the user tures include volume control on the hand- can store up to three numbers in memory set and double modular external jacks on and dial any one of them by just pushing the base station (one for regular phone - a button. The auto -dial feature is protect- line hookup, the other for any telephone ed against power outages by an easily CIRCLE 137 ON FREE INFORMATION CARD accessories, such as phone -answering changeable 9 -volt battery. There is also a devices, etc.) security system, programmable by the longer performance from a single charge The model FF -4000 has a suggested re- owner, to prevent unauthorized use of the than possible with any other cordless tele- tail price of $349.95.-Electra Company, system. phone. Special circuitry permits the hand- 300 E. Country Line Road, Cumberland, Very low power -level operation allows set to be recharged fully in under four IN 46229.

model 800T and model 805T, are ruggedly constructed injection molded cases, made of high -impact polypropyl- If you're looking for trouble, ene, combined with molded polyurethane you came to the right place. pal lets. ia a Cc: CI a

U11411p1thì ,,,4,,,,va CIRCLE 138 ON FREE INFORMATION CARD CI CI Model 800T (shown) measures 18 x 1312 x 6 inches, and has two pallets: it is priced at $107.00. The slightly smaller model 805T measures 18 x 131/2 x 5 inches, and has one pallet: its price is $87.00.-Platt Luggage, Inc., 2301 S. When you're testing circuitry, compatible models in 11 sizes. Prairie Avenue, Chicago, IL 60616. you need the best trouble- (They're also available with shooter around: The AP long, headless test lead pins for Test Clip. 411111bt attachment to AP The P/C Desk Console, has jumper been introduced for the Sharp PC -1211 It's made with a narrow cable Itit.1/ assemblies.) and the Radio Shack TRS-80 pocket com- nose shape that allows is of black for easy attachment on And every one puters with printer. Constructed high density boards. made with highest plastic and measuring 8.5 x 16 x 2.75 Nailhead pins that quality engineer- inches, it has room for three cassette ing -and industrial - keep probe hooks grade materials from sliding off ends. for long life and Open nose design that permits probe tip access reliability. to DIP leads. And a contact So don't go looking for trouble comb that fits between DIP until you've contacted your AP leads, eliminating any possi- PRODUCTS distributor and bility of shorts. All these little ordered AP Test Clips-the best design differences add up to the little troubleshooters around. DIP ultra -reliable, safe, quick Call TOLL FREE, 800-321-9668, troubleshooting you need. for the name of the distributor CIRCLE 139 ON FREE INFORMATION CARD You can buy AP Test Clips in nearest you. (In Ohio, call col- 22 standard or connector - lect: (216) 354-2101.) boxes, a full set of 3 x 5 -inch cards, two AP PRODUCTS paper rolls, a spare print ribbon. and the INCORPORATED interface cable. The P/C Desk Console is 9450 Pineneedle Drive priced at $19.95, plus $2.50 shipping, and P.O. Box 603 6% tax for CA residents.-Fox/Walker, Mentor, Ohio 44060 4650 Arrow Hwy., Bldg. G-17. Montclair. [216] 354-2101 CA 91763. R -E In Europe, contact A P PRODUCTS GmbH Baeumlesweg 21 0-7031 Weil 1 W. Germany

CIRCLE 36 ON FREE INFORMATION CARD www.americanradiohistory.com NEW IDEAS

Typewriter word counter

HERE'S A PROJECT THAT CAN SAVE YOU effect switch, which in turn resets the some time when you need a manuscript RS flip-flop. Subsequent spaces are NEW IDEAS of a specific length, such as for a school ignored until the next keystroke is project, a classified advertisement, etc. entered, and the entire cycle is repeated. This column is devoted to new ideas, It will keep track of how many words If the space bar and a key are struck at circuits, device applications, construc- you've typed, and display the total. The the tion techniques, helpful hints, etc. same time, the flip-flop's output is All published entries, upon publica- circuit uses Hall -effect switches (Sprague logic 1, and the next keystroke incre- tion, will earn $25. In addition, Panavise UGN-3020T, or equivalent) to detect ments the counter. will donate their model 333-The Rapid keystrokes and spaces. When the count reaches 999, the next Assembly Circuit Board Holder, having a It features eight - The Hall -effect switches negative will retail price of $39.95. an are sensitive transition clear the counter position rotating adjustment, indexing at to the presence of a magnetic field. In but set its overflow high. That overflow 45 -degree increments, and six positive this project, permanent magnets are output is latched by a second flip-flop, lock positions in the vertical plane, giving used to turn the switches on and off. I/4 of the 4043, driving the display's you a full ten -inch height adjustment for comfortable working. (See photo below.) When the magnet is near the switch, most significant digit (the 1 on the dis- the output from the switch is logic 0; play) on. The procedure then repeats, when the magnet moves away, the for a maximum count of 1999 words. switch opens and, because of the For this circuit to work, the Hall - 10,000-ohm pull-up resistor, the output effect switches and the magnets must goes to logic 1. be mounted inside the typewriter itself. The switches are connected to 1/4 of One switch and magnet should be a 4043 RS flip-flop. After the circuit has mounted so that they are close together been reset, the output from that flip- normally, but move apart when any key flop is at logic 1. At the first keystroke, is struck. The second switch and mag- the output from the Hall -effect switch net should be mounted so that they goes to logic 0, pulling the flip-flop's move apart when the space bar is hit. output to logic 0. The output from the The switches and magnets are mounted flip-flop drives the MC14553 three - using epoxy glue. Both sets of switches decade counter. That counter is nega- and magnets should be positioned so tive -edge triggered, so the transition of that the thick side of the switch (the the flip-flop's output from logic l to side opposite the dot) is normally near I agree to the above terms, and grant logic 0 increments the counter. The the magnet's south pole. Radio -Electronics Magazine the right counter's BCD output is then fed to the You can power the circuit any way to publish my idea and to subsequently 4511, a BCD -to -7 -segment display de- you wish. One good way would be to republish my idea in collections or com- pilations of reprints of similar articles. I coder/driver, which in turn controls the use a wall -plug transformer with a 9 - declare that the attached idea is my 31/2 -digit LED display. volt output. You could also use a 9-volt own original material and that its publi- Each subsequent key stroke is ignored battery. If you do that, you may want cation does not violate any other copy- until the space bar is hit. Hitting the to devise a display blanking circuit to right. I also declare that this material had not been previously published. space bar opens the space -bar Hall- extend battery life.-Larry Dighera

PRRMA1.I EL)T MAGNETS (SEE TEXT) tqV Title of Idea

r.l N V V Signature 31I2- KEY 1K C.C.llT 51RIGE is MC. e 44v 4511 MULTI - Print Name Date 14553 c PLExED MA 14 6 LED

1 0 K DISPLAY Street MSP

Zip I City State ^NN1. ALL I HALL- EFFECT 12 SWITCHES Mail your idea along with this coupon (SPRAGUE U&N-30.20T) k 144043 Q ---VMr to: New Ideas Radio -Electronics, 200 Park Ave. South, New York, NY 10003

FIG. 1

www.americanradiohistory.com SATELLITE TV RECEIVER o1e Pana CUl1(illlic'cl,ll'Ulil /rrl,'c' 5 3 Ottletir Scopes The Original... A First in the industry, with from SOLTEC (At the uplink transmitter, the video is over thirty years of use by pre -emphasized to reduce degradation satisfied customers. CORPORATION Spray Pack Mark II in quality during transmission and is gets into places of dithered-or dispersed-at a 30 -Hz rate close tolerance and to prevent interference to ground-based washes out the dirt, leaving a thin film of microwave links. The two processes -' lubricant which lasts must be "undone" to recover the , indefinitely, with zero UIETR original video information.) L effect upon current capacity and A de -emphasis network after Q4 Màhs4u resistance. made qp of R22, R23 and C45 removes SPRAY -PACK. Spray Pack Mark II LURRI-CLEANER has been tested and the pre -emphasis that was added at the IS TUNERS, SWITCHES, proven in the Space ROLS, POTS., RELAYS. uplink source. Transistor Q7 isolates Age and is still the n EiSIL'.[M1C, s',. SU the de -emphasis network from the OR AND MACK finest lubri-cleaner ,'M°...* w/probe 15MHz, Single Trace, video low-pass filter formed by C46 - a..ioxc. .ro..ou^ available. It is quick, N.,cK. ,.a., , safe, effective - a 1mV/Div to 2V/Div., w wwcn. A uut,, C48 and L8. That filter is needed to re- MUST for every tool 11 Ranges. Auto Fix CAUTION Triggering move the audio-subcarrier components caddy. Spray Pack Mark II from the video; sometimes they can NET WT 6O.' wreak havoc with devices like is the best -priced external lubri-cleaner. I kt e+ RF -modulators. It should be noted that Available at Leading Distributors all stages so far have been direct - Vtll+ry coupled to allow frequency response down to DC-an important factor for Product of good video. Transistors Q8 and Q9 form a x2 -gain amplifier/buffer stage QUIETROLE that drives C49 and D5, a simple clamp - stage that removes the 30 -Hz dither 455 Montgomery Budding 5595 that would otherwise cause the picture Spartanburg. SC 29301 w/probes 15MHz, Dual Trace, to flicker. Following the clamp stage, 803-582-4837 1mV/Div to 2V/Div, emitter -followers Q10 and Q11 provide CIRCLE 58 ON FREE INFORMATION CARD 11 Ranges. Auto Fix Triggering enough gain to produce a one -volt peak -to -peak video signal into a 75 -ohm load. COMPUTERS

Audio demodulator Complete Microprocessors line, peripherals 8 Terminals. FM audio from the satellites is trans- Green 12" Monitor ..$129.00 SOROC 10 135 795.00 B/W 12" Monitor ....109.00 TI -99/4 379.00 mitted on subcarriers in the 5.5 -7.5 - Visicalc 200.00 Epson MX -80 call us MHz range (with 6.8 MHz being typi- Microsoft Z/80 320.00 Color Monitor call us IDS PRISM 80 . .. .call us TI -810 1395.00 cal). making a tunable audio -demodula- TI -745 1440.00 80 Column Board ....299.00 tor a must. A high-pass filter consisting of C54, C55, and L9 couples the audio Texas Instruments

subcarrier to a second stage, IC7, Anal $ 20MHz, Dual Trace, PLL Invest. 42.00 TI -59 $175.00 Accessories Call us TI -55 II 3995 1mV/ Div to 2V/Div, similar to that used in the video section TI -58C 8000 Speak & Spell 4995 11 Ranges. Auto Fix Triggering with the exception that it operates only PC100C 155.00 TI Programmer LCD .54.95 over a 5 -8 -MHz range. Its center fre- TI BAIT 39 00 MBA ...49.95 quency is determined by the capacitance HEWLETT-PACKARD across pins 12 and 13. That capacitance HP/125 Computer ... ,call us HP -11C NEW call us is formed by a varactor diode (D6) and HP/37E ...... 72.00 HP -12C NEW call us C67. The bias on the varactor is ad- HP -33C 8500 HP -41C Mem Module ..26.00 HP -34C 115.00 HP-41CV 243.00 justed by the front -panel AUDIO potenti- HP -38C 114.99 HP -67 295.00 the voltage HP -41C Prog 188.00 HP-97 570.00 ometer; increasing increases HP -41C Printer 285.00 Quad Ram call us the frequency of the PLL. The PLL fol- HP -41C CRD RDR 16900 Application Pac call us lows the FM subcarrier and outputs de- HP/85 1995.00 HP/83 1670.00 modulated audio at pin 14. That audio is low-pass filtered by R43 and C64, SCM TYPEWRITER SPECIALS 30MHz, Dual Trace, and applied to a x 20 gain stage made up SCM 2200 ...... $284.00 INTREPID $274.00 1mV/Div to 2V/Div, of half of IC6, a dual op -amp. The out- SCM 2500 294.00 CLASSIC 12 .. .. 164.00 11 Ranges, Auto Fix Triggering put of 106 is 1 -volt peak -to -peak and is All units shipped in original cartons with accessories of driving a 600 -ohm load. according to manufacturer's specification. Send in stock now at your local capable money orders, personal check 2 weeks to clear. In Illinois add 6% sales tax. Add $6.95 minimum ship- SOLTEC®DISTRIBUTOR ping & handling charges per unit. We ship UPS. AFC Subject to availability. Written warranty for specific The AFC (Automatic Frequency products can be obtained free upon request. Above SOLTEC c prices are for mail order and prepaid only. Prices and Control) stage performs the important specifications subject to change without notice. Send CORPORATION function of keeping the 4 -GHz signal mail orders.. 11684 Pendleton St.. Sun Valley. CA 91352 in 25 wide 70 Toll Free: 1-800-423-2344 centered the -MHz -MHz that task sounds compli- rzóiiir s, 9,ic. or. in Calif. 1-213-767-0044 IF. Although 519 DAVIS EVANSTON, ILL. 60201 TEL 312-869-6144 cated, the AFC circuit is really quite

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www.americanradiohistory.com simple. Its heart is the TUNING potenti- from IC8, causing the Voltage drop ometer. R47, and a constant -current across the tuning potentiometer to de- source, IC8. That IC provides a current crease and pulling the receiver back on to the potentiometer, where a voltage frequency. drop takes place. The output of the is constant -current source is modified by Power supply a current mirror formed by D7 (a A simple full -wave bridge rectifier - 2N4123 transistor with its base and col- type power supply, shown in Fig. 8. RECIPES lector leads tied together) and Q12. By provides unregulated 18-volts DC for 11, 13 varying the current applied to that cur- the receiver, and IC 1C12, and IC Author Doi Lancaster takes a rent mirror, we can vary the current provide regulated 15. 12. and 5 -volts. unique ana innovative approach through the front -panel tuning potenti- respectively. The 18 -volt. 1 -amp. to CMOS and TTL with these two ometer, and thus the voltage drop power transformer is housed in a great books from Sams! across it. separate enclosure to reduce heat drift In CMOS COOKBOOK, he In effect, we "steal" some of IC8's in the receiver. outlines the differences between constant current; that tends to linearize In the next part of this article we'll CMOS and other MOS designs the tuning characteristics of the first present foil patterns and parts -place- and describes CMOS' many local -oscillator. Integrated circuit IC6-a ment diagrams for the receiver, along advantages. An actual mini - lists pinouts and is used to drive the current mirror and with assembly instructions. R -E catalog for more than the circuit performs a voltage -to -cur- applications 100 different devices. rent translation. The output voltage from the demodu- Support the In TTL COOKBOOK, Don takes a look at TTL logic circuits and lator (taken from the emitter of Q4) is demonstrates many kinds of filtered by R33 and C52 to remove any March of Dimes for this BIRTH DEFECTS FOUNDATION practical applications trace of video signal, so that all that's most inexpensive and most left is a control voltage representing a widely applicable form of frequency. That voltage is applied to electronic logic. the non -inverting input of IC6-a and Help satisfy your basic electronics controls the voltage to the current appetite with these easy-reading, translator, causing an AFC action to information -packed Sams take place. If the signal drifts higher. cookbooks! Order both of them the AFC circuit steals more current THIS SPACE CONTRIBUTED BY THE PUBLISHER today and save over 15%!

U CONVENIENCE iß --SPRING LOADED Model 324 TENSION BAR T THE ELECTRONIC WORK CENTER TM SAMS BOOKS SUGGESTED Qua.., . RETAIL PRICE Maimeime- CMOS COOKBOOK, No. 21398 812.95 TTL COOKBOOK, No. 21035 $11.95 Set of both books, No. 21958 $19.95 $49.95 PRECISION Amount of Order $_ ADJUSTMENT Add local sales tax where applicable 8 Add Handling Costs 8- KNOBS Total Amount of Order - TILTS, TURNS Check Money Order VISA & ROTATES MasterCard Interbank No SOLDER Account No SOLDER _ IRON Expiration Date HOLDER HOLDER Full payment by check, money order, or charge card must - accompany your orde' Name (Print) SIX INDIVIDUAL COMPARTMENTS Signature Address PANAVISE City State Zip Contact your local dealer today. Call 800-428-3696 tor I -free, or 317-298-5566 for the name of your local Sams Book outlet or to order by phone (give Sams Operator the code number in the box below). Offer PANAVISE PRODUCTS, INC. 2850 E. 29th St., Long Beach, Ca. (213) 595-7621 good in USA only and expires 8/31/82 Prices subject to change without notice. AD167

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INSIDE BASIC GAMES, by Richard Mateosian. Sybex, 2344 Sixth Street, Berkeley, CA 94710. 325 pp including appendix and in- TOOLS FOR dex; 7 x 9 inches; softcover; $13.95. Assuming that the reader has some knowledge of BASIC programming, TOMORROW'S this book teaches him or her how to design error - free interactive BASIC programs, including games and other "real time" situations. Eight different kinds of computer games TECHNOLOGY (a total of 14 games) are described in detail, then completely analyzed to illustrate how the games were designed and developed in BASIC. All aspects of game -program design, including program structuring, cursor positioning, randomization, and other concepts are discussed. Programs for games such as SLANT Hangman, Ten -Key Flicker, and Taxman are coded in Microsoft EDGECUTTERS BASIC, and versions are provided for the PET/CBM, APPLE II, and TRS-80. CIRCLE 121 ON FREE INFORMATION CARD

EXPERIMENTS IN TELECOMMUNICATIONS, by Morris Tischler. Gregg Division, McGraw-Hill Book Company, 1221 Avenue of the Americas; New York, NY 10020; 186 pp; 81/2 x 11 inches; softcover; $7.95. EXPERIMENTS IN GENERAL AND BIOMEDICAL INSTRUMENTATION, by Morris Tischler; same publisher and format; 201 pp; $8.95. These two books are part of a series presenting linear IC's in a DIAGONAL variety of circuit applications, and are written for use by elec- EDGECUTTERS tronics technicians who have a basic knowledge of transistors and test instruments. Each volume covers theory and application through laboratory experiments and tracks with standard electronics -course coverage. Step-by-step lab procedures re- inforce learning with hands-on activities using common lab equipment and devices presently used in industry. CIRCLE 122 ON FREE INFORMATION CARD

HANDBOOK OF OSCILLOSCOPES: Theory and Application, by John D. Lenk. Prentice -Hall, Inc., Englewood Cliffs, NJ 07632. 340 pp including index; 61/4 x 91/4 inches; cloth; $19.95. This new and revised edition carries through all the features CURVED of the first edition, bridging the gap between oscilloscope theory ROUND NOSE and practical applications. It is designed as a basic textbook for student technicians, hobbyists, and experimenters, and as a guidebook for experienced working technicians and engineers. Each chapter has been expanded to include new material, and existing information has been updated to reflect present-day trends, especially in the extensive use of curve tracers. The revision also simplifies much of the material in the first edition. Assuming that readers are not familiar with the operating principles of oscilloscopes, the opening chapters present simplified details. Chapter one through four cover oscilloscope basics-typical operating controls and characteristics, specifications and performance-as well as a brief description of oscilloscope accessories. Throughout, the descriptions are kept to the block -diagram or simplified level; unnecessary and elaborate circuit descriptions are avoided. CIRCLE 123 ON FREE INFORMATION CARD

HANDBOOK OF MICROPROCESSOR APPLICATIONS, by John A. Kuecken. TAB Books, Inc., Blue Ridge Summit, PA 17214. 308 pp including index; 51/4 x 8+ inches; softcover; $8.95. "What can a microprocessor not be used for? It will not mend a : broken heart. It will not It AVAILABLE AT YOUR DISTRIBUTOR ensure justice among all men. will not bring happiness to the lonely. It will not perform its functions ADVANCED instantaneously. Outside of those constraints, there is very little TOOL that it cannot do or assist in doing."... So starts this book, whose object is to show the principles of TECHNOLOGY inc microcomputers and to demonstrate some of the nearly infinite numbers of ways in which the microcompressor can be applied 18217 PARTHENIA ST NORTHRIDGE, CA 91325 to measurement, process sequencing, "smart" instruments, and (213) 993-1202 some of the more traditional computer applications.

CIRCLE 39 ON FREE INFORMATION CARD www.americanradiohistory.com The book is written with the assumption that the reader has no ANNOUNCING TWO familiarity with binary arithmetic, BCD, hexadecimal or octal notation: because of that. those subjects are all treated early in the discussion. NEW TERMINALS Emphasis is placed upon the use of the microprocessor in the Smart Fast Graphics Matching Modem and $295 Printer control, sequencing, and measurement functions and the mani- Netronics announces a state of the art breakthrough in terminals, now at prices you pulations of bits and bytes at the machine or assembly -language can afford, you can go on-line with data -bank and computer phone -line services. It's all level in which most of the simple evaluation kits operate. It is not yours: "electronic newspapers," educational assumed that any of the extensive "development systems" are services, Dow -Jones stock reports, games, recipes, personal computing with any level available to the reader. language, program exchanges, electronic bulletin boards .. and more every day!!! is to render the use of microproces- The basic aim of the text Netronics offers two new terminals. both sors are simple as possible in the widest span of applications. The feature a full 56 key/128 character typewriter - style keyboard, baud rates to 19.2 kilobaud, a same subjects have been treated in different locations in the text rugged steel cabinet and power supply. The simplest one, FASTERM-64, is a 16 line by 64 or 32 character per line unit, with a serial from different viewpoints, so that a second and perhaps third printer port for making hard copy of all incoming data, and optional provisions for block and with the same topic will generate greater familiarity special character graphics. The "smart" version, SMARTERM-80. features either 24 line by 80 encounter characters per line or 16 by 40 characters per line, it offers on -screen editing with page -at -a - and understanding of the less -familiar concepts. time printing, 12,000 pixel graphics, line graphics, absolve cursor addressing, underlining, reverse video, one-half intensity and much more ... simpy plug them into your computer or CIRCLE 124 ON FREE INFORMATION CARD our phone modem and be on-line instantly. Use your TV set (RF modulator required) or our delay green -phosphor monitor pictured above. For hard copy just add our matched printer. Price breakthrough!!! Own the FASTERM-64, a complete terminal kit. ready to plug in for HANDBOOK OF SIMPLIFIED RADIO, PHONO, AND TAPE RE- just $199.95 or order the SMARTERM-BO kit for just $299.05, (both available wired and tested.) Be online with the million -dollar computers and data services today ... we even supply the CORDER REPAIRS, An Illustrated Troubleshooting Guide, by necessary subscription forms. James Edward Keogh and Ben Suntag. Parker Publiishing Com- More good news: All the components in our terminals are available separately (see what need!!! pany, Inc., West Nyack, New York 10994. 236 pp including coupon), so you buy only you x FASTERM64 ... DISPLAY FORMAT: 64 or 32 charactersll:ne by 16 lines ... 96 displayable appendices and index; 6 9 inches; softcover, spiral binding; ASCII characters (upper & lower case)... 8 baud rates: 150, 300, 600, 1200, 2400, 4800, 9600, $16.95. 19, 200, (switch sel.) ... LINE OUTPUT: RS232/C or 20 ma current loop ... VIDEO OUTPUT: IV P/P (EIA RS -170) ... CURSOR MODES: home & clear screen, erase to end of line, erase cursor The car radio keeps fading in and out...the tape -recorder play- line, cursor up & down, auto carriage return/line feed at end of line & auto scrolling REVERSE VIDEO... BLINKING CURSOR ... PARITY: oft, even or odd ... STOP BITS: 1, 1.5, back is on the blink...the pickup arm on the stereo refuses to lift. 2 ... DATA BITS PER CHARACTER: 5, 6, 7 or 8 ... CHARACTER OUTPUT: 5 by 7 dot matrix in a 7 by 12 cell ... PRINTER OUTPUT: prints all Incoming data 1K ON BOARD RAM ... For most people, repairs on three items like those would come 2K ON BOARD ROM ... CRYSTAL CONTROLLED ... COMPLETE WITH POWER SUPPLY ... OPTIONAL GRAPHICS MODE: includes 34 Greek & math characters plus 30 special graphics to considerable expense at a repair shop. characters ... ASCII ENCODED KEYBOARD: 56 key/128 characters. This book is a simplified, time -saving guide that shows you SMARTERM.60 . DISPLAY FORMAT: 80 characters by 24 lines or 40 characters by 16 lines 128 displayable ASCII characters (upper & lower case) 8 fraud rates: 110, 300, 600, 1200, 2400. how to troubleshoot radios, phonographs, and tape recorders 4800, 9600, 19, 200 .. LINE OUTPUT. RS232/C or 20 ma current loop ... VIDEO OUTPUT: IV pp (EIA RS -170) ... EDITING FEATURES: insert/delete line, insert/delete character, for- quickly. Through step-by-step troubleshooting charts, you will ward/back tab ... LINE OR PAGE TRANSMIT ... PAGE PRINT FUNCTION ... CURSOR POSI- TIONING: up, down, right, left, plus absolute cursor positioning with read back ... VISUAL find the source of the problem. Locate the symptom in the ATTRIBUTES: underline, blink, reverse video, half intensity, & blank .. GRAPHICS: 12,000 appropriate chapter and simply follow the troubleshooting pixel resolution block plus line graphics ... ON -SCREEN 'PARITY INDICATOR ... PARITY: off, even or odd... STOP BITS: 110 baud 2. all others 1 ... CHAR. OUTPUT: 7 by 11 character in chart. The malfunctions are listed according to the most likely a 9 by 12 block ... PRINTER OUTPUT . . 60 OR 50 Hz VERTICAL REFRESH ... BLINKING BLOCK CURSOR... CRYSTAL CONTROLLED ... 2K ON BOARD RAM ... ASCII ENCODED occurrences. Not only are you told what component to check, KEYBOARD: 56 key/128 character . 4K ON BOARD ROM ... COMPLETE WITH POWER SUPPLY but also how to make the necessary tests so that you can narrow TELEPHONE MODEM 103 OIA ... FULL DUPLEX, FCC APPROVED DATA RATE. 300 baud to its cause. steps are INTERFACES. RS232/C and TTY .. CONTROLS: talk/data switch (no need to connect and the problem down primary Succeeding disconnect phone), originate/answer switch on rear panel ... NO POWER SUPPLY RE- then outlined. QUIRED ASCII KEYBOARD ASCII.3 ... 56 KEY/128 CHARACTER ASCII

Once you know what the trouble is, it's a matter either of re- ENCODED UPPER & LOWER CASE . FULLY DEBOUNCED ... 2 KEY ROLLOVER POS OR NEG LOGIC WITH POS STROBE pairing or replacing the component. This book shows you how REQUIRES +5 & -12V DC (SUPPLIED FROM VIDEO BOARDS) to make simple repairs, when that is possible, as well as indicat- PRINTER COMET I ... SERIAL 110 TO 9600 BAUD ... 80 CHARACTER COLUMN (132 COMPRESSED) . 10" TRACTOR FEED ing at what point a replacement is the only solution to the prob- UPPER/LOWER CASE ... INDUSTRY STANDARD RIBBONS 4 CHARACTER SIZES ... 9 BY 7 DOT MATRIX ... BI-DIRECTIONAL lem. PRINTING CIRCLE 125 ON FREE INFORMATION CARD Continental U.S.A. Credit Card Buyers Outside Connecticut TELECOMMUNICATION TRANSMISSION HANDBOOK, 2nd Edi- CALL TOLL FREE 800-243-7428 tion, by Roger L. Freeman. John Wiley & Sons, Inc., One Wiley To Order From Connecticut Or For Tech. Assist. Call (203) 354-9375 Drive, Somerset, NJ 08873. 707 pp including appendices and NETRONICS R&D LTD. Dept. RE index; 61/2 x 91/2 inches; hardcover; $49.50. 333 Litchfield Road, New Milford, CT 06776 For practicing telecommunications engineers and advanced students, this standard handbook-now fully revised and up- Please send the items checked below: dated -provides the practical and real -world information needed COMPLETE FASTERM-64 TERMINAL (includes FASTVID-64 video board for telecommunication design for single links or for complete ASCII -3 keyboard, steel cabinet and power supply) ... kit $199.95 plus $3 P&I wired & tested $249.95 plus $3 P&I ... graphics option: add $19.95 to networks. It treats the technical expertise of 14 transmission each of above disciplines with a unified telecommunications -system approach. COMPLETE SMARTERM-80 TERMINAL (includes SMARTVID-80 video board, ASCII -3 keyboard, steel cabinet and power supply) ... kit $299.95 plus Because many engineers are unfamiliar with some aspects of $3 P&I ... wired and tested $369.95 plus $3 P&I transmission technology, each chapter begins with an examina- ï7 FASTVID-64 VIDEO BOARD (requires +5 & -12V DC) ... kit $99.95 plus $3 P&I ... graphics option add $19.95 ... wired & tested $129.95 plus $3 P&1 ... tion of key concepts, which are then applied to the specific en- graphics option add $19.95 gineering situations. That integrative approach makes available SMARTVID-80 VIDEO BOARD (requires +5 & +/-12V DC) ... kit $199.95 plus $3 P&I ... wired & tested $249.95 plus $3 P&1 a wealth of on-the-job techniques that can be used in any area of ill DELUXE STEEL TERMINAL CABINET ... $19.1t5 plus $3 P&I transmission -problem solving, whatever the engineer's specialty. ASCII.3 KEYBOARD (requires +5 & -12VDC) ... kit $69.95 plus $3 P&I .. . wired and tested $89.95 plus $3 P&I Many tables, nomograms, and curves illustrate basic principles L POWER SUPPLY (powers ASCII -3 keyboard & video boards) ... kit only and suggest additional applications. $19.95 plus $2 P&I ZENITH VIDEO MONITOR (high resolution green phosphor) ... wired & CIRCLE 126 ON FREE INFORMATION CARD tested $149.95 plus $6 P&I L TELEPHONE MODEM MODEL 103 O/A ... wired & tested $189.95 plus $3 INTERFERENCE HANDBOOK, by William R. Nelson, WA6FOG. P&I L. DOT MATRIX PRINTER Comet I ... wired & tested $299.95 plus $10 P&I Radio Publications, Inc., Box 149, Wilton CT 06897. 247 pp in- Li RF MODULATOR MOD RF -1 ... kit only $8.95 plus $1 P&I cluding index and data on other recommended handbooks; 51/2 [ : 3FT-25 LEAD MODEM/TERMINAL OR PRINTER/TERMINAL CONNECTOR CABLE ... $14.95 ea plus $2 P&I x 81/e inches; softcover; $8.95 plus $1.00 for postage and handling.

This book tells how to locate and cure RFI (Radio Frequency For Canadian orders, double the postage . Conn. res. add sales tax. Interference) relating to TV, stereo, radio, power lines, and tele- Total Enclosed $ phones. Problems in all of those areas are analyzed and solved. E Personal Check E Cashier's Check/Money Order There are many photos, diagrams, and charts. Suppression cir- VISA E MasterCard (Bank No. cuits for interfering devices are discussed in detail, as well as Acct. No. Exp. Date protection techniques for home -entertainment equipment. Signature Interference is a fast-growing problem, and there will be more Print Name tomorrow than there is today. This handbook is designed to be Address D of service to those confronting that world-wide obstacle to clear, City State Zip reliable electronic communication. R -E Nco CIRCLE 127 ON FREE INFORMATION CARD CIRCLE 41 ON FREE INFORMATION CARD 107

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www.americanradiohistory.com r TTL 7400 SERIES MICRO COMPUTER THE SIMPLE SOLUTION 7400N .23 74389 42 741009 1.34 741545 1.25 741939 75 TO I.C. 74019 .25 74409 .25 7410414 .64 74155N .58 74194N 75 SELECTInN 740214 .24 744214 .52 74107AN .40 741579 .58 74195N 55 SUPPORT CENTRE 74039 .24 74459 .89 741099 .40 741599 1.52 741969 79 1982 IC MASTER 74049 .26 74469 .79 74110N .52 7416014 .80 741979 .79 74059 .26 7447AN .79 74111N .72 74161AN .69 741989 1.39 7406N .36 74509 .25 74116N 1.38 741629 .89 741999 1.39 UNBEATABLE! 740714 .41 7451N .29 741209 1.38 741634.11 .69 74221N .68 74089 .26 74539 .29 74121N .38 741649 .69 742469 1.70 MEMORY RAM SPECIALS 74099 28 74549 .29 741229 .48 74165N .69 742479 1.50 Deluxe 3500 Page 2 -Volume Set .69 74251N 89 7410N .26 74729 .34 741239 .48 74166N 55,000 I.C. Devices 74129 .35 74739 .35 741259 .48 74170N 1.75 742599 1.89 2114-30 4K STATIC 8117.95 74139 .42 74749 .35 74126AN .48 74172N 3.95 742739 1.99 150 Manufacturers . 74149 .44 74759 .47 74128N .84 7417314 .79 742769 1.19 2400 Complete Data Sheets 7416N .36 7476N .35 741329 .48 741749 .66 742789 2.38 4116-30 16K DYNAMIC 8 / 14.95 741714 .36 748369 .48 74136N .52 74175N .66 7427921 .76 from 62 Manufacturers 1.99 .95 741769 .77 742839 1.10 74209 .25 748469 74141N WITH SHUNTS AND INSTRUCTION FOR TRS 80 UPGRADE. Quarterly I.C. Updates 74229 .45 7485N .88 741429 2.95 741789 1.17 742939 .95 74239 .29 7486N .35 741439 3.41 741799 1.35 742989 .84 Included in Price 74259 .32 7490AN .38 741449 3.44 741809 .75 743519 2.20 74269 .32 7491AN .50 741459 .67 741828 .52 7436569 .59 STATIC RAM'S Regularly $82.50 74279 .32 7492AN .42 741479 1.50 74184N 239 743669 .59 2101.35 1K (256 o 4) 350NS 22 PIN 2.95 ACTIVE'S PRICE 74289 .48 7493AN .38 741489 .99 741659 236 74367AN .58 $69.95 7430N .23 7494AN .65 7415014 1.25 741909 .75 7436865 .59 2102.25 1K (1K x 1) 250NS 16 PIN 1.75 74329 .38 7495AN .54 741519 .54 74191N .75 743909 .96 2.65 74339 .42 749614 .59 74153N .48 741929 .75 743939 1.49 P2111-45 1K (256 X 4) 450NS 18 PIN 1.89 74379 .38 7497N P2112-35 1K (256 x 4) 350NS 16 PIN 3.25 P2016.10 16K (2K x 8) 'MONS 24 PIN 29.95 MICRO CCi11PUTEFIS TTL 74LS SERIES ROCKWELL SYNERTEK SYM-1 7415147N 1.96 74152215 .89 741532154 3.95 P2016-15 16K (2K x 8) 150NS 24 PIN 15.95 74LSOON 21 741,5739 35 AIM 65 M. Microcomputer Development 741501N .22 742.57461 35 741_5148N 1.43 741_5240N 1.25 74153229 4.95 13.95 7415029 .24 741,5759 45 741_5151N .43 741524121 1.25 74LS323N 4.95 P2016-20 16K (2K x 8) 200NS 24 PIN The Professional Computer Board 7410039 .24 741.5769 44 74151535 42 74152429 1.25 741.53249 325 (4K o 8) 450NS 28 PIN 36.95 4K VERSION 1 K Version $239.00 7410049 25 741_5789 38 74151558 .97 74152439 1.25 741.534814 1.65 Z6132.6PS 32K 74150554 .25 741_58314 N 741515614 87 741.5244N 125 74153529 1211 Super $489.99 4K Version $259.00 74150814 25 7415859 .M 741515714 .48 741_5245N 1.95 74103539 1.26 Special 7415099 .25 741.58614 38 741515814 .48 741524714 .84 74L5362N 6.59 DYNAMIC RAM'S 7415109 .24 7415909 42 741.516021 .79 741.524814 1.09 74153659 ; 28 741_5919 99 741_5161N .75 74152499 1.10 74L5366N .59 TEXAS 74151121 P4060-30 4K (4K o 1) 300NS 22 PIN 2.65 Complete documentation 741.51214 .25 74LS92N 54 741_5162N .84 741_5251N .69 74L5367N .59 INSTRUMENTS 7410139 .36 7415939 54 7415163N .89 7415253N .69 74L5368N .59 P4116.20 16K (16K x 1) 200NS 16 PIN 2.65 suppliedhed -write or call 74151414 .48 741.59551 52 741_5164N .58 741_5257N .69 74LS373N 1.95 TM990/1.189 7415209 .24 7415969 72 741_5165N 89 741_5258N .89 74153749 1.95 P4164-25 64K (64K x 1) 250NS 16 PIN 19.95 University Module 42 741.016614 1.64 741_5259N 1.19 74103759 for a free brochure 741.5219 .27 741.510721 Complete Microcomputer 7415269 .25 741010921 38 74151709 1.59 741_5260N 1.25 74L5377N 1 P4164-20 64K (64K x 1) 200NS 16 PIN 17.95 741.52714 .29 74151129 36 741517314 .72 741.3266N .12 74LS378N Learning Aid.'' $299.00 74LS30N .24 74151229 45 7415174N .M 741_52739 1.19 74L5379N 1.09 7415329 .27 741512314 69 74151759 .44 74152759 3.39 74153909 1.44 KEYBOARD SPECIAL 7415379 .29 741_5125N 49 741_5181N 1.99 74152799 .44 741539314 1.44 EPROM'S BRAND NEWT 7410389 .29 74151269 49 741_5189N 4.45 741528014 1.96 74L5395N 1.19 C2708-45 8K (1K x 8) 450NS 24 PIN 4.50 7410429 .44 7415132N 58 741519014 .85 74152839 .88 741,044714 Prime industrial quality full 83 key 7415479 .72 7418133N 49 74151919 85 74LS2909 .79 74154909 1.89 16K (2K x 8) 45ONS 24 PIN C2716/ keyboard with numeric keypad. 7415489 76 741,513614 42 741_5192N .74 74102939 .79 741063061 64 00 Single 5 Volt Supply, Intel Pin Out 4.95 741,5519 .24 741_5138N 55 74151939 .74 741_0298N .99 74L5669N .84 TMS2516 Latest ferrite core switches for superb 2.75 74156709 1.99 7415549 .24 741.01399 55 741,5194N .74 741_5320N TMS2716 16K (2K x 8) 450NS 24 PIN 1LL reliability and long life. 7413559 .24 741_5145N 109 74151979 .88 Gp 3 Power Supply, T I Pin Out 12.95 iGQ" Serial output is in epsidic format. C2532 32K (2K x 8) 450NS 24 PIN Easily changeable to ASCII output. US eull Ideal for micro CMOS T I Pin Out 13.95 -computers. terminal C04001BE 25 CD4024BE .53 C04052BE .85 CD4520BE .70 CD4085BE .75 C ects and word rocessors. C04002BE .25 CD4025BE 25 C04053BE .75 CD4522BE .99 CD4086BE .75 C2732 32K (4K x 8) 450NS 24 PIN New Price Over $150.00 NOW ONLY 69.95 CD4006BE .79 CD4026BE 1.95 C040608E .99 CD4526BE .99 CD4093BE .56 Intel Pin Out 13.95 5/O CD4007BE 24 CD4027BE .45 CD40668E .49 CD45278E 1.47 CD4099BE 1.25 Ql)01 Modification Kit (Specs and Parts C04008BE .75 CD40288E .54 CD4068BE .35 CD4528BE .85 CD4104BE 2.34 C2564 64K (8K x 8) 450NS 24 PIN to convert to ASCII) 9.95 .99 40097PC .83 CD4009BE .39 C040298! .75 CD4069BE .25 CD4531BE T I Pin Out VERY SPECIAL 29.95 CD4010BE .39 CD40308E .38 CD4070BE .35 C04532BE .99 40098PC .97 CD4011BE 1.87 .99 74C00N .34 A 64K (8K x 8) 300NS 28 PIN 25 CD4033BE CD4071BE 25 CD4539BE C2764 ACTIVE ELECTRONICS IS A DIVISION OF FUTURE CD4012BE .25 CD40348E 1.99 CD40728E 25 CD4543BE 1.21 74C14N .65 Intel Pin Out 29.95 CD4013BE .39 CD4035BE .75 CD40738E .35 CD4553BE 3.19 74C20N .34 ELECTRONICS, ONE OF THE WORLD'S LARGEST CD4014BE .75 CD4040BE .84 CD4075BE .28 CD4555BE .75 74C76N .41 FRANCHISED DISTRIBUTORS. WE ARE THE CD4015BE .75 C04041BE .79 CD40768E .59 CD4556BE .75 74C85N .79 SOURCE, THE UNIQUE SUPPLIER OF FACTORY CD4016BE .39 CD40428E .58 CD4078BE .28 CD45818E 1.89 74C107N .53 BI -PROMS CD4017BE .70 CD4043BE .65 CD4510BE .64 CD4582BE .89 74C161N .99 FRESH, TOP QUALITY CURRENT PRODUCTION x 8 16 PIN 1.98 CD4018BE .75 CD4044BE .55 CD4511BE .99 CD4584BE .42 74C163N .99 74S188N 32 MATERIAL. OVER $40 MILLION IN STOCK. CD4019BE .39 CD4046BE .78 CD4512BE .99 CD4585BE .79 74C173N 1.15 748288N 32 x 8 16 PIN 1.98 CD4020BE .70 C04047BE .85 CD4514BE ISO CD4702BE 15.95 74C175N .75 CD4021BE .75 CD40498E .38 CD4515BE 1.88 CD4081BE .25 74C192N 1.03 93417/82S126 256 x 4 16 PIN 2.45 CD4022BE .79 CD40508E .38 CD4516BE .75 CD4082BE .25 74C193N .99 256 x 4 16 PIN 2.45 CERAMIC CAPACITORS C04023BE .25 CD405113E .79 C045198E .45 93427/82S129 100 AND 500 VOLT. MIN 10 PIECE PER VALUE. 93436/7620 512 x 4 16 PIN 4.95 ALOE 1-99 100. VALU: 1-99 100. VALUE 1-99 100. 30Pí .077 .065 33074 077 .965 00331AF 077 095 PLASTIC POWER 93446/7621 512 x 4 16 PIN 4.60 .077 065 and TRIAC'S 73Pí .077 .045 470P .077 0047MF SCR'S .077 065 TRANSISTORS x 47Pí .077 .065 560P' .077 .055 00501AF 93448/7641 512 8 24 PIN 7.95 .077 965 TIC106D SCR 5 amp 400V TO -202 .39 68Pí 0n .065 0010PF 677 0068145 TIP29B .48 TIP41C .89 TIP125 .74 93453/7643 1024 x 4 18 PIN 6.95 5/Pc .077 .065 0012Pf .065 0100MF .10 08 TIC116B SCR 8 amp 200V TO -220 1.06 965 .11 08 TIP29C .50 TIP428 .89 TIP126 .82 I2oPs 077 .065 0015PF .ói 0150Mf TIC116D SCR 8 amp 400V TO -220 1.19 93451/82S181 1024 x 8 24 PIN 17.95 150PF .077 .085 022GPF 077 085 0200MF 13 n 11P308 .48 TIP42C .74 TIP127 .89 12 T1C1268 SCR 12 amp 200V T0-220 1.18 ieaPs .077 .065 0027PF 077 065 0330MF .14 TIP30C .48 TIP110 .58 TIP140 1.54 82S185/7128 2048 x 4 18 PIN 14.95 210PF 9N .077 1000MF 15 13 TIC1260 SCR 12 amp 400V T0-220 1.48 TIP31A .49 TIP111 .84 TIP141 1.84 82S191/7138 2048 x 8 24 PIN 78.00 TIP318 .49 TIP112 .72 TIP142 2.05 TIC2168 Triac 6 amp 200V T0-220 1.12 TIP31C .52 TIP115 .56 TIP145 1.99 TIC2160 Triac 6 amp 400V TO -220 .94 EPROM, PROM and PAL Programming Services Available. ALUMINUM ELECTROLYTICS TIP32A .46 TIP116 .84 TIP146 1.99 TIC226D Triac 8 amp 400V TO -220 1.10 Guaranteed 24 Hour Turnaround Time. Please include Truth muAL TIP328 .50 TIP117 .75 TIP147 2.45 TIC236D Triac 12 amp 400V TO -220 1.30 Table or Master PROM with your order. 631.047 .13 7033 .37 35/330 .36 TIP32C .56 TIP120 .74 TIP2955 .93 TIC246D Triac 16 amp 400V TO -220 1.60 100/.17 100133 .39 50/330 160/0.47 7 637330 TIP41A .85 TIP121 .84 TIP3055 .75 1 291595 SCR amp 50V TO -220 .65 100/1 A8 63147 .30 6/170 18 TIP41B .85 TIP122 .74 294442 SCR 8 amp 200V 10-127 1.29 Microprocessor 63/22 .3r 25/47 .31 101470 25 1001?.2 .48 70147 .30 161470 47 35/33 .16 100/17 30 100/470 1.4s 50/3.3 15 2550 24 6/1000 25 LINEAR IC'S OPTOELECTRONICS Chip Sets 40/47 .26 400175 1.45 16/1000 1.36 63147 28 10100 .14 4011000 2.eo LM309K 1.35 LM741CH .59 L.E.D. 6800 6500 8080 25/6.8 .90 25/1000 salvo LED 209 T-1 3mm Red .10 25/10 26 63/100 10k200 LM323K 4.50 LM741CN .29 63110 30 1®1100 1.11 LED 211 T-1 3mm Green .19 FAMILY FAMILY FAMILY 1612200 LM324CN .48 LM747CN .50 100110 .28 10'220 1.95 LED 212 T-1 3mm Yellow .14 6502 CPU 7.45 8035 CPU 5.45 10/15 18 40220 1.45 6800 CPU 4.95 .ss LM339CN .48 LM1488CN .64 LED 220 T-1 5mm Red .11 25/22 27 63220 50/2200 2.95 3/4 6802 CPU 7.95 8039 CPU 7.95 100/22 .23 100/220 120 LM348CN .99 LM1489CN .64 LED 222 T-1 3/4 5mm Green .24 6504 CPU 7.65 11114700 162 6808 CPU 8.45 080A4.95 6/33 .15 2®/220 2.25 1614700 1.99 18 LM555N-8 .29 LM2240CN 1.80 LED 224 T-1 3/4 5mm Yellow .16 6505 CPU 7.65 8085 CPU 7.95 35/33 .25 6330 25/4700 2.85 6809 CPU 19.95 63/33 .35 2m1330 35 LM556CN .68 LM3403CN 1.19 7 SEGMENT DISPLAYS 6810 2.65 6520 5,95 8155 9.00 LM567N-8 .99 LM4136CN .88 .99 6821 2.65 8748 27.95 FND500/TIL322 7.95 6522 RESISTORS .45 LM4558CN .44 FND507!TIL321A, .99 6840 7'95 8755 32.00 5% 6845 16.50 1/4 AND 1/2 WATT RESISTORS - ULN2003AN .79 MAN 71A I DL 707R 1.25 6532 10.85 8212 2.25 6850 2.95 AVAILABLE VALUES FROM 1 OHM TO 9.1 MEG MAN 72A I DL 707 1.25 8214 4.25 6852 3.45 6551 11.10 1/4 WATT 100 PIECES OF ANY VALUE ONLY 4.59 `ili { 8216 1.98 - 112 WATT 100 PIECES OF ANY VALUE ONLY 4.99 3.44 CALL US FOR BULK QUANTITY DISCOUNTS * * * BONUS * * * 1 AMP VOLTAGE Z80 FAMILY 2.34 Any order received over 82246 REGULATORS NEW LOW PRICES 8228 4.95 TRANSISTOR $ 100 - we will send you 180-S10/0 19.95 8251 6.95 DUAL -IN -LINE 78XXUC POSITIVE .69 9.95 SPECIALS at no extra charge Z80 -CPU 6.50 180-510/1 19.95 8253 2N404A 1.48 LOW PROFILE Zilog Software Manual 79XXUC NEGATIVE .79 1808 -CPU 7.15 180A -S10/1 22.95 8255 5.05 I.C. SOCKETS 190-P10 5.25 180-S10/2 22.95 8257 9.95 2N2222A .24 Unitrode Data book VOLTAGES 5, 6, 8, 12, 15, 18, 24. 180A -PIO 6.25 Z80A-SIO/2 22.95 8259 9.95 CONTACTS PRICE CONTACTS PRICE Low Power Schottky Z90-CTC 5.25 Z80 -S10/9 14.00 8P79 10.95 2N2907A .23 8PIN 13 22 PIN 35 78XXKC POSITIVE 1.57 15.00 14 PIN .22 24 PIN 38 Data book 190A-CTC 6.25 Z80A-S10/9 2N3055 .85 g -t. 79XXKC NEGATIVE 1.79 Z80 -DMA 13.50 Z80 -DART 10.20 .15 16 PIN .25 28 PIN 44 MOS Memory Data book 1808 -DMA 16.50 2808 -DART 11.20 2N3904 18 PIN 28. 40 PIN 63 VOLTAGES 5, 8, 12, 15, 18, 24. `TOTAL VALUE OVER $30 2N3906 .15 20 PIN 31

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ELECTRO SPACE PRINTED ELECTRO SPACE PRINTED CIRCUIT Pin Straightening Tool puts devices on CIRCUIT CARD EJECTORS CARD INJECTOR/EJECTORS FOR 1/16 then -true row to row spacing. One side Is for .300 For 1/16 thick cards (.072 slot) THICK CARDS center devices, flip tool over for devices on .000 Stock No. Color 1.24 24.49 511p 11452 While centers Put device in tool. squeeze. bowed leads 0.27 923 8-20 come back to proper spacing. 11450 White S 25 921 5.19 11453 Red 27 23 .20 11451 Red 25 21 .19 BelonTh II Aner \ Stock No. 11059 $12.95

Texas Instruments Low Profile ELPAC POWER SUPPLIES Sockets, Im plated phosphor bronze contact SOLV SERIES FULLY REGULATED pIns with gas -tight seat. ARIES Output ZERO Stock No. No. Pins 1-24 25-99 100 -Up Stock Output CurrentDimensions(HaWeD) INSERTION FORCE SOCKETS 11201 a 5.15 813 0.12 No, Voltage Rating In Inches Price - Cam actuated. true zero insertion force 11202 14 18 .15 .14 13802 5 3.04 4.7/164402 $38.00 HEX-WIK SUPERIOR SOLDER - lin plated solder tail pins 11203 16 21 18 .16 13803 12 1.54 4.7/1130442 38.00 REMOVAL BRAID capable of being plugged into DIP sockets 11204 18 24 .21 19 13804 15 1.2A 4.7/15444 38.00 Stock No. No Pins 1.24 25-49 50Up 41205 20 27 24 .21 13806 24 0.754 47/1130402 38.00 Braid 11055 24 54.06 93.60 53.25 11208 22 30 26 23 13808 5 13.04 5'5/e04.7/803.3/18 57.00 Stock No. Size Ft/Spool Price 11056 28 4.25 3.77 3.40 11207 24 33 .30 .25 13809 12 4.04 5.5/804'7/843.3/18 57.00 50041 1/18 6 52.10 11057 40 4.90 4.34 3.91 11208 28 38 34 .29 13810 15 3.3A 5.5/844.7/843.3/16 57.00 50042 5/64 6 2.25 11058 64 9.89 8.78 7.90 11209 40 .53 45 .40 13812 24 2.04 55/804-7/883.3/16 57.00

RCA C/MOS RCA POWER ELPAC POWER SUPPLIES DC/DC CONVERTERS Stock SINTEC RCA No. 1-24 25-49 SINTEC RCA No. 1-24 25-49 No RCA No. 1-24 25 -Up 40122 C1220 $1.22 91.16 44037 2N4037 f .88 5 .82 Stock Input ut 44001 CD400115E S .36 S .33 42322 723220 1.46 1.38 .76 Dimensions 45294 2N5294 .80 No, Voltagye VoltOta e Outputurrent 44002 004001UBE .36 .33 42700 T27000 2.07 1.98 45296 2N5296 .80 -78 44007 C04007U6E 300 MW Type iVDCI IHIncIn hes Price .36 .33 428001 T280013 1.58 1 50 45320 2145320 1.25 1 19 44011 004011BE 13825 3,07.0 12506 Ó 25 .40,51 x3.05 57.00 .36 .33 428002 T28000 1.90 1.79 45321 295321 1.02 .96 13828 44012 CD4011UBE 36 .33 3.07.0 1220.8 Oß5 .480.5103.05 7.00 42850 T28500 2.06 1.95 45322 295322 1.61 1.53 13827 3.0.7.0 1520.7 7.00 44013 CD40138E 56 .52 40029.1 TIP29 .60 57 45415 295415 1.80 1.52 0.20 A8, 51,3.05 44015 13828 3.0-7.0 1530.7 0-20 .484,5103.05 7.00 CD40158E 1.07 1.01 40029.2 TIP29A .64 51 45418 295418 2.17 2.06 13829 44016 CD4018BE .59 .55 40031 TIP31A .74 70 3.0.7.0 2850.7 0-10 .480.5103,05 7.00 45784 265784 1,37 1.29 13830 3.07.0 2820.7 .48x.5103.05 7,00 44017 C040178E 1.07 1.01 40121 TIP121 1.43 1.35 48044 2106044 2.04 1.93 alo 44019 00401913E .59 55 40125 TIP125 1.37 1.29 48101 296101 1.25 1.19 44020 C040205E 1.18 1 12 42955 MJ2955 1.18 1.10 413103 2518103 1.25 1.19 1.5 W TYPE 44023 CD4023BE .36 .33 43055 RCA3055 1.03 .97 46107 296107 .82 .73 13831 4.0.7,0 1220.6 125 .65101.201.77 23,00 44024 0040246E .92 .87 42102 292102 1.28 1.22 46109 2146109 .82 .78 13832 4,07.0 1220.8 125 .65141,201.77 23.00 44025 CD40258E 38 .33 42270 2N2270 .82 .78 46111 296111 .80 ,78 13833 4.07.0 1520.7 100 .85101,201.77 23.00 44027 CD4027BE 68 .64 43053 293053 .61 .58 46254 296254 2.16 2.05 13834 4.07.0 -1500.7 100 .65141.201.77 23,00 44030 C040308E .59 55 43054 2N3054 1.37 1,29 46290 296290 .80 .76 13835 4.07,8 2821.4 50 .65141.241_77 23.00 44040 C D40408 E 1.18 1.12 43055.1 293055 1.03 .97 46292 296292 .80 .78 13836 4.07.0 2821.4 50 .65141.241.77 23.00 44048 C040465E 1.56 1.48 43055-2 2 3055110 1.82 1.54 46388 296386 1.05 .99 44049 C04049BE .57 54 43439 2613439 1,73 1.85 1.15 1.09 46387 298387 "Floppy Disc" power supply for 8 drive. as built by Shugart, CDC, Wang°, 44050 00405013E.4 43440 2N3440 1.25 1.19 46388 296388 1.28 1.22 44051 CD4051BE 1.1B 1.12 etc.. three outputs +5V, +24V. 5V1. Output current max (2.54, 3.0A/3.4A 43771 293771 2.92 2.78 46474 296474 1.03 .97 PK, O.SA). No. 13801 5109,00 44052 0040528E 1,18 1.12 43772 293772 3.18 3.00 48887 2N8667 1.49 1.44 Stock 44053 CD40538E 1.18 1.12 43773 293773 3.22 3.04 46668 298888 1.60 1:52 44054 CD4054BE 1.96 1.85 44036 294036 1.08 1.02 40347 40347 1.22 1.18 44056 00405813E 1.96 1.85 44060 C040606E 1,48 1.40 Stock No. O,.cnptlon MODUTEC 44066 0040868E .78 .74 Price - VOLT/OHM M4ham meter ¡Stock No. 13725) 534.75 47555 2706 56 E PROM 5 4.75 44089 C04069U6E 36 .33 - Battery Tesleriorsmall batteries from 1 35V to 4.5V (Stock No. 13733) 513.95 41630 2516 tee E PROM 44070 C040706E .44 .41 755 - Mlniclamp AC Volt -Ammeter 471132 271e Ise E PROM 44071 CD40718E 36 .33 MEMORIES 7.95 47635 2532 32o E PROM 15.75 AC Amperes Bow Rosin Core Solder 1.213 44078 0040768E 1.20 (RAMS, E PROMS) 471137 2734 ]211 E PROY Stock No. Ranges Price 44081 0040818E .36 .33 47tH 15.7s 160/40 Alloy) 2164 eke E PROM 37.º5 13730 0.254 $39.50 44093 C040935E ,78 .74 47046 21144.-3 1K a 4 Length Weight STATIC RAM 4.75 13731 0.504 44098 C040985E .1.56 1.48 47045 4044 414 STATIC RAM 39.50 01 440 13732 0.1004 39,50 Stock No. Dia. (feet) 100 Price 44502 C04502eE 1.72 1.84 47550 4116-3 RIK DYNAMIC RAM 3.50 50075 .082 9 1,5 03.28 44511 CD4511 BE 1.26 1.20 - LINE SPLITTER allows last & accurate 50076 .062 25 4 4.36 44522 CD4520BE 1.18 1.12 adinge of AC power consumption 50077 062 50 8 8.02 44590 CD22100E 2.49 2.35 IC Insertion/Extraction Kit includes DIP IC sotnn°n mart.n (Stock 013727) 5 9.95 50078 .032 33 1.5 4.08 tO from 44591 CD401038E 1.96 1.85 accomodste all IC's 14 to 40 pine, C/MOS safe. and OM-MULTITESTES Versatile Volt -Oh,, 50079 .032 89 4 5.16 44592 C040106BE .ee .80 Stock No. 13309 534.95 Milliammter (Stock 013729) $13.95 50080 .032 175 8 6.82

110 CIRCLE 74 ON FREE INFORMATION CARD

www.americanradiohistory.com Radio Shack Parts Bring Your Ideas to Life! No Waiting! No Minimum Order! Low Prices!

Solar Power Demo Kit Here's a Fast, Easy Way Engineer's Notebook II To Design and Build! 4404.4 NEW! Design and Debug Your Circuit On a NEW! Socket, Transfer It to the PC Board Only 995 1i1H11Í11111111I1[IIIÍill1(lllîit1i11111111111: :11HH!#NilllïlfflilillllllllllllHHIIHIHI_ 249

-I Ready to Use Ideal for Models a By Forrest Mims III I A top-quality solar cell pre -wired to a precision DC motor- ready for your creative ideas! Great for building into model Gives you practical circuits for most analog and digital windmills, boats, radiometers and more. Includes minia- ICs. information, presented\ in easy -read A wealth of an -to ture propeller, color wheels, illustrated booklet. format. 128 pages. Punched for three-ring binder. 277-1201 9 95 276-5002 2 49 Now That It's Working ... Computer Connectors Solderless, Reusable Type a ' J 0

p Pre -Drilled PC Board. Holes match sockets (® and ` 1j for easy transfer Vim, x 57/,e x 1,6", with 0.3" DIP center. 550 connection points. 276.170 ... 3.29 C7 Modular IC Breadboard Socket. DIP center El 995 NEW! © 695 These boards snap together for larger projects and accept 30 to 22 -gauge solid wire. Two busses, 550 Dress project! Both of deluxe up that special these enclo- indexed connection points. 2Ve x 6". 276-174 ... 10.95 feature vented top, -to -work sures steel easy aluminum © Modular IC Breadboard Socket. As above, but chassis, removable rubber feet and great -looking with 270 indexed connection points. 2'/e x 35a". Fig. Description Cat. No. Each 'TRS-80 gray" styling. 276-175 6 49 A D -Sub Male for RS -232 276-1559 4.99 Fig. Size Cat. No. Each o Accessory Panel. Snaps into interlock groove of B 25 -Pin D -Sub Female 276-1565 4.99 A 3'/e x 7,12x 57/e" 270-229 9.95 B. Allows you to mount controls, switches and read- C 40 -Position Card -Edge 276-1558 4.95 x 2r/s". 1 B 21/2 x SV,e x 45/2" 270-228 6.95 outs. 5% 276-171 99 D 34 -Position Card -Edge 276-1564 4.95 TV Horizontal Joystick Pot SPDT_ DIP Relay Photo Bargains! Output Transistor - NEW! 495 \111299 Includes Contacts Rated

795 Mounting I 1 Amp at 125VAC TO -3 Case Template 2SC1308. Top-quality NPN replaces 5 DC, 56-Ohm Coil. Sensitive. Sub- ECG -238, GE -38, SK -3115 in many 19" Great for video games, computers, radio mini size and ideal for PC board or color sets. With insulator, bushings. Why control and more! Twin 100,000 -ohm lin- DIP socket mounting. 3/e x 5/8x 1,6". pay more? 276-2055 7 95 ear pots. 1" -long control. 271-1705... 4.95 275-216 2 99

Mercury Switch Micronta® Test Equipment Values i51 Xenon Strebe Flashtube. Bright, long - life. Great for projects or replacement use. Trigger voltage: 4kV. Anode: 300V maxi- 89° mum. 200V min. With specs. 272-1145 2 99 Cé; 4kV Trigger Coil. Use with ftashtube (above). Requires 200.300VDC primary source. With wiring diagrams. This submini gravity -actuated switch is ideal 272-1146 1 49 for tamper alarms, position detecting and more. Rated 100 milliamps at 24VDC. LASCR Photo Detector. Fast response ideal 275-025 89C makes it Vor "slave" photoflash units. 1995 3495 TO -92 case. 276-1095 1 99 Micro Test Clips 5 -Volt Reed Relay Digital Logic Probe. Simplifies digital troubleshooting by indicating high, low or pulsed logic states - 149 with LEDs. Powered by circuit under test. Only 22-301 19.95 Mile a Pkg. of 2 O 27 -Range VOM. Measures AC/DC volts, ohms, DC milliamps, decibels. Big 4" mirrored scale. 30,000 996 Insulated ohms per volt DC sensitivity. With leads, manual. Re- Spnng-action-ideal for testing on hi -den- quires and 9V batteries. 22-203 "AA" 34.95 DPST contacts rated 0.5 amp at 125VAC. sity PC boards. 1 42" long. type. Solder 5 -volt, 180 -ohm coil. PC board red, mountable. One one black. 275-228 99C 270-370 Pkg. of 2/1.49 IC Protector Mat 'Phone Adapters DC Microammeter Binding Post Set NEW!

pmnay ¡Cut 33% 1 Only , Reg. 8.95 39 e f O V." Stereo Phone Jack to l/a" Stereo Phone Plug. Use standard -. Pkg. of 2 896 stereo headphones with the new mini 595 5 x 5" conductive foam mat protects sen- portables. 274-366 2 59 Secure contact with push to release. Ac- sitive ICs from static charges. Pays for B Vs" Stereo Jack to V." Stereo 0 to 50 Microamps DC. Precision Jeweled cept up to 14-gauge wire. Includes one itself with the first chip it saves! Plug. Use "mini" headphones with movement and easy -to -read face. red, one black. 274-660.. Pkg. of 2/1.39 276-2400 896 std. jacks. 274-367 2 39 270-1751 ... Sale 5.95 ftadue IhaeK A DIVISION OF TANDY CORPORATION OVER 8200 LOCATIONS IN 76 COUNTRIES Retail prices may vary at individual stores and dealers

CIRCLE 66 ON FREE INFORMATION CARD

www.americanradiohistory.com C/MOS TRANSISTOR SPECIALS CPU'S & SUPPORT CHIPS 2NI307 PNP 0E70 5 IN404APNPGE10.5 1 03 Ern 917 .%1 A RVREP - PNP GE ] ®N 379 8251 oez 4081 n 4C84 - 50 GP 408i r5 2034 % 62% 4086 2N62n- NPR SWITCHING POWERK % 40% 130 AMD2%1 8.% 6269 - 6.% 4083 MRS aD39 C8 RF TRANSISTOR NPN 75 4Re1 4501 40% 140 2N3172NPNS,TO3 1W MICROWAVE 8202 %.% 8252IAM86171 - 4510 85 KIT 4009 4CÁ9 - 50 8112 8X3n - 25.03 2a 4010 4C% 2NIJeBJ NPN SiR 3 8214 CPU 6.75 }3919 3.% MA - NPR SoTOIRF 1 93 4216 2.% 2604 510 - 12% 4515 2N1011NPN I00 CONVERTS 8224 325 230P10 - 5% 60 2N21IINVNSoT018 5 100 4519 30 2N2307PNPS17019 95 IRS 9927NL - 9% 5. 1 00 $8995 MICROWAVE TO IN3055NPNS,T0 3 822678ï 288 8260 4L 16 15 2113904 NON SoT0 92 8228 4.% 6945 4561 fi, VHF TELEVISION 81% 116 6810 -23232% 15 N625 84C% 26NPNSTOIlO 4019 30 2N5109PNP S, I0 220 RAM' ROM's 7¢42 20 TIP 319NPN5iT0230 HC% 30 v3211PNPS,TO2n COMPLETE INSTRUCTIONS, 8284141.11 10.% 2793 4022 2114.3 2718 r 6V 14C14 6 60 TIP III PNP 41193 3 1.46 51384._.. 00 HARDWARE, POWER 2132 4024 GP PNSoLM SUPPLY 41162 2.25 ..IS MJE30% 0080 }1L%J .% 16% ]4G7 & YAGI ANTENNA. 7916 340B 1.% 2732 11 7 74163 60 K4018.3 3.% 925Z1 1.60 TTLIC SERIES 14164 % M8409611 3.% 925112 2.% 00 80 81163 3% 625115 3.% 7400 17 CLEAR -VUE ELECTRONICS - 7472 - 35 74166 JO M54%01 L 3.% 825123 1.% 7401 - .17 7473 35 74167 1.25 MM6230 1.76 9251% SPECIALS 7402 - 17 7474 -- .40 74170 1.60 Box 600, Rochester, MI 48063, 2101.1 2.46 825130 1.1,30 1403 .. 17 7475 40 74173 .104-44LLNP 2.% 82513, 1.60% mac 74.81.11 -

7404 .- 24 7476 - 74174 65 1.93 62181 300 Nam 6 *P.O. 313-375-9730 IMl%1 4.% 3619A 2.% 74903 1 AI 7405 24 7480 45 74175 00 ram 14.5111 Hain .40 74176 5101E 2% AM92,4C 2% 7406 - 33 7463 - 50 75 4656 1 1p

2111AL 3 4fi 8256511411091 7407 7485 - 74171 75 a 74905 144.797 - 35 65 74.575 Mae 7408 27 7486 .42 74180 75 24911 lam 110 745.210 7409 - 28 7490 - 05 74181 1.90 7.2110 UART's 50 7410 - 17 7491 - 45 74182 AS AVS1013 - 3.25 WK. 2 25 Tan - 22 7492 - 45 74190 70 TRlm2s - 3.59 COM2017 74. 144157 125 /412 - .30 7493 45 74191 75 MICROWAVE television "downconverters" PT 1492.9 - 3.25 AY3B700 7413 - 42 7494 - 00 74192 70 under $50.00. Highest quality, easily 7414 assembled. INTERFACE SHIFT DOUBLE SIDED DIP RIBBON - .50 7495 . 60 74193 79 7416 33 7496 00 741% .65 Catalogue: $2.00 (refundable). NDS, Box 12652- ft DRIVERS REGISTERS CABLE JUMPER ASSEMBLIES 7417 -. - 37 74107 35 771195 - 45 R, Dallas, TX 75225. F01791 34.% re.. 7420 - 17 74121 - 35 74196 - 75 16 PIN 4"LONG $ 2.00 14% % MM14% 7425 30 74122 --39 74197 .- 75 488 1 10 MMH04 7426 33 74273 66 HOW to 14 PIN 12"LONG $ 2.50 - 74123 - .42 - build data splitter, wye cable, line driver, 6130 2.% MM%13 zw 7427 - Al 74125 - e5 74279. 60 ®0 2.30 MMb55 250 ASCII character generator, and their 7430 17 74126 74365. 65 power sup- 9831 2.% MM%% 2.% RS 232 CABLE - 45 7432 27 74145 743 plies. - Schematics, 4844 200 MM%68 2.% 75 1166 ASCII waveform chart. EIA 10 0 7437 27 74148 1.25 74367 - .65% 9837 2 CO 7.5068 2.% Conductor, 22 color coded wire, - specs. $14.95. JOHN MUIR, P.O. 7438 27 74150 - 74390 - _90 Box 1274, Vic- 88% 200 M%% 2.% gray PVC outer cover, diameter 1.10 MSLt 950 %" 7440 U 74151 - 50 75324 - 1.75 torville, CA 92392. 0404530 2% .40 per ft. - 1009530.00 7441 - .75 74153 40 76325 - 1.50 7642 - 45 75154 1.10 75492 1.05 SUBSCRIPTION Television Add 20% postage for orders under 100' 7445 80 70155 - 50 ST31 Microwave Down - 74 PIN HEADERS 3/51.00 - 2.00 1446 15 74157 .50 8T32 - 2.75 converters; UHF Sinewave Systems 16 PIN HEADERS .40 Add 10% postage for orders over 100'. using Ad- 7447 65 74160 - .85 9601 - 75 vanced Circuitry and Technology. 24 PIN HEADERS .75 2114L-4 - 1.65 4116-2 1448 - 65 74161 65 9602 - 75 External TV 40 PIN HEADERS 1.10 81380A - 3.75 TMS9927NL - '050 II 74162 80 D59056. - 1.56 connections. Fifty other complete kits available. OVA CPU 600 50 PIN EDGEBOARD CONN 3.95 - CRT CONTROLLER - 9.95 6264147662164K RAM 8275 CRT CONTROLLER FULL WAVE BRIDGE 12V DC RELAYS Send $10.00 for All Plans And Prices to: BETA 26 PIN EDGEBOARD CONN 2.50 10.95 ITL SIZE - - 16.95 PRY 271 ELECTRONICS, 2081-G 50 PIN ANGLE 3.95 6A 25A 3rd Street, Riverside, RIGHT CONN. 2732-32K ROM - 14.95 F01791 SP. 12110 anm ca I - 346 00 0 20 PIN RIGHT ANGLE CONN 2.25 2764-25 - 39.95 6845 - 16.95 CA 92507. 200 60 1 30 2 20 D.v 2500 o5m 50 PIN RIBBON CONNECTORS 93.25 400 100' i.651330 SPECIALS GOOD THRU 1982 T2! 00 PIN RIBBON CABLE CONN 62 75 MAY ELECTRONIC items and kits, for free 600-1 30 i 1 90 i 4 40 catalog 20 PIN RIBBON CABLE CONN 12.25 10 write: DAC INDUSTRIES, 6005 Musket Road, PIN RIBBON CABLE CONN $1.50 DIP SOCKETS PRINTED CIRCUIT BOARD MINIATURE MULTI TURN TRIMMING POTS Fort Washington, PA 19034. SPIN 17 22PIN 30 - 6' DOUBLE SIDED EPDXY BOARD THICK 50, 100.500, 10, 505.250K ..575 each 3/92.00 5.60 ee. 5.82 60 14 PIN 20 24 P1N 35 16 PIN 22 28 PIN 40 HUNDREDS of telephone, surveillance, transmit- EPDXY GLASS VECTOR BOARD DIP SWITCHES 18 PIN 25 40 PIN 60 ter, receiver, and other products, kits, and plans. NO. 30 WIRE WRAP WIRE CTS 206 4 4 POSITION 125 Catalog $1.00. INTERTECH, P.O. Box 54853, At- 1116" 7510k with 1110 Spacing SINGLE STRAND 100'..61.40 CTS 206 7 7POSITION '40 74L I lanta, GA 30308. 41A" x 6'h" $1.95 CTS206 8 8POSITION 150 CTS 206 IO 10 POSITION 195 DAC-013EO PRINTED circuit handbook, sixty pages. Nine DATEL'S SPOT - 110 TOGGLE SWITCHES 200 DPOT tse diy methods. Send $12.00 plus $1.75 shipping. 8 bit DAC -$ 4.95 DPDT - CENTER OFF 41 CRYSTALS ZOWTIAK, 750 Little Matterhorn, Salt Lake City, taro 3.000 5.000 8.000 SCR's TRIAC's UT 84107. 18.432 M.2549.9. I 3,579 6.000 10.000 13.25 a_ 20.000 4 000 6.144 18.000 1.5A BA 35A 110A PRV lA 10A 25A SUBSCRIPTION television education manual. R E DICON SAD 1024 ANALOG DELAY LINE ..110.% 100 45 60 1.40 100 45 .60 155 200 70 so 1 90 9.ºD 200 84 :äó 2.10 Complete theory and circuits $9.95. Parts and 1.20 7 WATT LD 66 LASER 400 1.40 2.60 12.00 400 130 1 90 j 10 kits available. D & S ENTERPRISES, P.O. Box DIODE(IR)$8.96 r00 1.80 3.60 15.00 E]00 200 2.75 4.30 110901 RE, Nashville, TN 37211.

L14 1 -IR DETECTOR. .. 25 watt Infra Red Pulse 1.00 (SG 2006 equiv.) FP 100 PHOTO TRANS.. Laser Diode (Spec sheet included) 824.95 RED. YELLOW. GREEN or AMBER LARGE LED 2" 100 RED, GREEN BIPOLAR LED's. 55 REPAIRS 2N3820 P FET ...... 8 .45 MLED92IR LED 2N 5457 N FET 5 .45 MRDI4B PHOTO SARI_ %TOR 50 ATARI games repaired within 48 hours. Mail in 2N2646 UJT 8 .45 TIL 119OPTO ISOLATOR 60 ILSOPTO ISOLATOR 45 with your check for $34.95. Return postage in- ER 900 TRIGGER DIODES.. .. , 4151.00 1 WATT 2N 6028 PROG. UJT 9 .65 ZENERS: 3.3. 4.7. 5.1, 5.6. 6.8, 8.2, 9.1, 10, V.G.M. REPAIRS, 2558 12.15,18, ar22V I.OU cluded. Hempstead DISC Tpke., East Meadow, NY 11554 CAPACITORS SFC 3301 50 PRV 30A 1UF 16V 10 51 00 .100/58.00 - .0111F 35V 16 51.00 100/65.00 FAST RECOVERY DIODE (35ns) . $2.25 FOR IN414811N9141 15/1.00 20KV 250MA DIODE $1.90 SALE MICROWAVE receiver TANTALUM CAPACITORS h:114tíTePM1o11YI1 7:1xei11ylM:i system. Write: "Dealers Wanted," Dept. RE, POB 4181, Scottsdale, IOUF 35V 8 .40 AZ .47UF35V 5.51.00 - 22UF 10V - 8 .30 PRV 1A 3A 12A 50A 125A 240A 85258 (602) 941-9395 .68UF35V 5/51.00 15UF 16V 3/01,00 100 .06 .14 .35 .90 4.25 8.00 1UF35V 5/81.00 30UF6V 5/51.00 SCANNER/monitor accessories-kits and fac- 2.2UF20V 5/51.00 200 .07 .20 .40 1,30 5.25 9.00 33UF20V $ .60 tory assembled. Free catalog. CAPRI ELEC- 3.3UF20V 4/51.00 400 .09 .25 .65 1.50 6.50 12.00 47UF20V 8.85 TRONICS, Route 1 R, Canon, GA 30520 4.7UF35V 4/81.00 600 .11 .30 .80 2.00 8.50 15.00 68UF 10V 81.00 LINEAR 6.8UF35V 3/51.00 800 .15 .35 1.00 2.50 10.50 18.00 CIRCUITS 120UF6V 6 .75 POLICE/fire scanners, scanner crystals, anten- 1000 .20 .45 1.25 LM3M 200U 20V 51.75 3.00 12.50 26.00 301 718 30 00358 50 10 45 nas, radar detectors. HPR, Box 19224, Denver, c 25 M%1 I49 - 456 LM3n CO 80219 CLOCK CHIPS % I% 40 SANKEN 747 LM380 - .% LM=L'64 F606" - r60 MM5314 LM382 b LA11 AUDIO POWER AMPS 94.75 MM5316 54 95 LM. - - TEST equipment, new and used. Catalog $1.00. MM5387AA.... 5.95 e1% % B A3U18 'ry% L397 - 1. ó cAn3e - 1 % PTI, 110118756, White Bear Lake, MN 55110. (612) Si 1020 G 20 WATTS .$12.50 LMnI 1.141363 - CA3M0- % LM553-2 25 CA30%- % 429-2975 LM300 45 193940 t 20 Si 1050 G 50 WATTS .$27.50 .5V at BOOma SOLAR CELLS - 113339 LM666 6 19a01 - 95 60 5643 - 3% 11351 %IBCC - 3 % THE Intelligence Library. Restricted technical 200 PRV 1A LASCR .95 3" diameter $4.35 LF3% 1 25 N55994 9% 1. 6. 1% i1 062 CP - % secrets -books on electronic surveillance; lock- % Lf3%355 % `A Tl%4CN 1 % I.7% investigation, etc. Free 7 SEGMENT DISPLAYS LM311 picking, demolitions, RS232 LM]18 1 % FSC8024-4 brochures: MENTOR, Dept. Z, 135-53 No. digit DL -707 C.A..3". 5 .75 REGULATORS Blvd., CONNECTORS C.C. 8" display ..55.95 DL 747 C.A..6" .. , .01.50 175 Flushing. NY 11354 78105 5 .45 FND503 C.0 ..5" $ .85 FND810.8"CA ....81.95 LM337 52.50 DB 25P male 02.75 LM305G 9 75 FND510 C.A. 5" .5 .85 FND803.8"CC ....51.95 79HGKC 5V et 54 S6.95 MICROWAVE 2 GHz. Best in the West! Down - DB 25S female 3.75 723 5% 340T-5, 6. 6 9. 12, DL -704 .3" C.0 5 .85 MAN 5 C.C. Green 5 .75 32075.12,157124 9 15, 180124V S .85 converter kits $39.00. Complete with antenna HOODS 125 90 MAN 82 C.A. Yellow .5 .75 78.05 9 35 LA51412.12V3A93.95 and control box $99.00. Factory assembled - 90 -day warranty $159.00. POSTAGE ADD 10% FOR ORDERS UNDER 825.00 TERMS:FOB CAMBRIDGE. MASS. SEND CHECK SENO $25 FOR WR CATALOG GALAXY ELECTRON- OR MONEY ORDER. MINIMUM TELEPHONE, FEATURING TRANSISTORS e RATES ADD 5% FOR ORDERS BETWEEN 825.00 050.00 ICS, 6007 N. 61st Ave.. Glendale AZ 85301 (602) AND C.OD PURCHASE ORDER OR CHARGE 620.00 RECTIFIERS. 146 HAMPSHIRE ADD 3% FOR ORDERS ABOVE 850.00 MINIMUM MAIL ORDER 1500 ST.. CAMBRIDGE. MASS. 02138 247-1151 CHEMICALS, apparatus, project books, wide TEL. (617) 547-7053 selection. Catalog $1.00 send to: PIONEER LTD. IND, 14a Hughey St.. Nashua, NH 03060 drSOLID STATE SALES WE SHIP OVER OVER 95% P.O. BOX 74D OF OUR ORDERS WITHIN RESISTORS Y4W,1/2W 5% carbon films 3e ea. NO 24 HOURS SOMERVILLE, OF RECEIPT MINIMUMS. Cabinet assortments, 1% metal 4if MASS. 02143 films. Request details. Bulk pricing TOLL FREE 1-800-343-5230 available. JR INDUSTRIES 5834-C Swancreek, Toledo, OH FOR ORDERS ONLY 43614

112 CIRCLE 72 ON FREE INFORMATION CARD

www.americanradiohistory.com One -Stop Component Center TIVI This is a partial listing of over 600 items available Belrtaont, California 94002 from 600 authorized Jim-pak Distributors: TTL ',fee geffl LS Schottky MT 7400 2/ 85 7490 85 74LS00 55 74L5109 75 7402 2/ 85 7493 85 74L502 55 74L5123 . . . . 1.49 7404 2/ 85 74100 2 25 74 LSO4 69 74 LS138 . . . . 1.29 7406 2/1 19 74109 2/1 19 DIP JUMPERS AND CABLE ASSEMBLIES 74 LS06 55 74L$139. . . . 1.29 74LS10 74L5154 . . . . 1.95 7407 2/1 19 74121 69 DJ -14-1 14-Pin 1 -Foot Single -End (Dip Jumper) $2.95 55 7408 2/ 89 74123 99 74LS14 1 09 74LS157 . . . . 1.19 DJ -16-1 16-Pin 1 -Foot Single -End (Dip Jumper) 3.25 7410 2/ 85 74150 1 95 74 LS30 55 74 LS 161 . . . . 1.29 7414 99 74154 1 95 DJ -24-1 24-Pin 1 -Foot Single -End (Dip Jumper) 3.95 74 LS32 69 74 L5174 . . . . 1.19 . . . 7417...... 2/1 10. 74157 99 DJ -40-1 40 -Pin 1 -Foot Single -End (Dip Jumper) 7.95 74 LS38 69 74 LS175 . 1.19 7420 2/ 85 74161 1 19 74LS42 129 74LS192 . . . 1.49 DJ -14-1-14 14-Pin 1 -Foot Double -End (Dip Jumper) 4.25 7447 119 74164 159 74 LS47 1 29 74 L5193 . . . . 1.49 7474 69 74174 1 59 DJ -16-1-16 16-Pin 1 -Foot Double -End (Dip Jumper) 4.95 74 LS48 1 79 74 LS221 . . . . 1.49 7475 79 74175 1 49 DJ -24-1-24 24 -Pin 1 -Foot Double -End (Dip Jumper) 5.95 74 LS73 75 74 LS244 . . . . 1.89 7476 69 74192 1 19 74 LS74 69 74 LS245 . . . . 3.49 DJ -40-1-40 40 -Pin 1 -Foot Double-End (Dip Jumper) 11.95 7485 1 19 74193 1 19 74 L575 75 74 LS367 . . . . .89 7486 2/1 19 74367 99 DJ -14-3-14 14-Pin 3 -Foot Double-End (Dip Jumper) 5.49 74 LS85 1 49 74 LS374 . . . . 1.95 7489 2 99 74393 1 95 DJ -16-3-16 16 -Pin 3 -Foot Double -End (Dip Jumper) 5.95 74LS90 89 81LS97 2 29

DB25P-4-P DB25P - 4 Foot - DB25P (Cable Assembly) 16.95 POTENTI DB25P-4-S 0B25P - 4 Foot - DB25S (Cable Assembly) 17.95 SOCKETS I,( DB25S-4-S DB25S - 4 Foot - DB25S (Cable Assembly) 18.95 ele JE215 Adjustable Low Profile Wire Wrap 8 pin LP . . . 2/.59 14 pin WW tin .75 14 pin LP . . . 2/.69 14 pin WW gold 1.09 Dual Power Supply 16 pin LP . . . 2/.79 16 pin WW tin .79 18 pin LP . . . 2/.89 16 pin WW gold 1.19 3/4 Watt @ 70°C General Description: The JE215 is a Dual Power 20 pin LP . 2/.99 24 pin WW gold 1.69 2 Watt ce70°C 15 Turn Pot. Supply with independent adjustable positive and nega- 22 pin LP . . .2/1.09 40 pin WW gold 2.75 7/8" Slotted Shaft Linear Taper 24 pin LP... .79 14 p. plug/cover 1.29 tive voltages. each Linear Taper 100 Ohm, 500 Ohm, output A separate adjustment for 28 pin LP. . . .82 16 p. plug/cover 1.39 1K, 5K, 10K, 25K, 50K, 1K, 5K, 10K, 50K, of the supplies provides the user unlimited applications 36 pin LP... .99 24 p. plug/cover 1.95 100K, 1 Meg 100K, 500K, 1Meg for IC current voltage requirements. The supply can 40 pin LP... 1.19 Also, The Molex Line CMU $2.95 830P $1.79 also be used as a general all-purpose variable power supply. DIODES & TRANSISTORS FEATURES: N751 . . DATA BOOKS JPTTL Im-Pak7400/74LS TTL 53.95 2/ 59 2N2219A. .2/1.19 Adjustable regulated power supplies, N757 2/ 59 2N2222A. . . . 2/.89 JPCML im -Pak CMOS/Linear 4.49 pos. and neg. 1.2VDC to 15VDC. JPMPD im -Pak Micro./Display 3.95 N1188 2 69 2N2907A. . . . 2/ 89 Power Output (each supply): N3600 99 30001 National CMOS 6.95 e 5/ 99 2N3055 5VDC @ 500mA, 10VDC@750mA, 2 30003 National Linear 9.95 N4001 4/ 59 2N3772 25 12VDC@500mA, and N4004 4/ 69 2N3904 2/ 69 30005 National TTL Logic 9.95 15VDC@ 175mA. 30009 Intersil 7.95 N4007 4/ 79 2N3906 2/ 69 Two, 3 IC regulators 79 10400 Intel Component 10.95 -terminal adj. N4148 10/ 99 2N4401 2/ with thermal overload protection. N4733 2/ 69 2N4403 2/ 79 Heat sink regulator cooling N4734 2/ 69 2N5129 2/ 69 /me, CMOS ImoP LED "on" indicator N4735 2/ 69 2N5139 2/ 69 Printed Board Construction N5401 3/1 19 TI P29A . . . . 89 4000 55 4030 75 120VAC input N5408 3/199 TIP31A . . . . 99 55 4040 1 79 4001 Size: 3-1/2"w x 5-1/16"L x 2"H 4002 59 4044 1 39 4006 1 49 4046 1 95 JE215 Adj. Dual Power Supply Kit (asshown) .. $24.95 CAPACITORS 4009 79 4047 2 75 Dipped Tantalum ELECTROLYTIC 4010 79 4049 79 lmfd @35V 2/.89 lmfd @50V 3/.66 4011 55 4050 89 47mfd @35V 2/.89 4.7mfd@50V 2/.59 4013 79 4051 59 lmfd @35V 2/.89 lOmfd @50V 2/.69 4016 79 4066 1 95 JIM-PAK 2.2mfd@25V 2/1.09 22mfd@50V 2/.79 4017 1 39 4069 69 3.3mfd@25V 2/1.19 47mfd@SOV 2/.89 4018 1 39 4070 75 KITS 4.7mfd@25V 2/1.39 100mfd @50V .59 4020 1 4071 69 Mr 39 10mfd@25V 1.19 220mfd@50V .69 4023 49 4081 59 33mfd@25V 3.95 1000mfd @25V 1.19 4024 1 19 4093 1 19 JE730 JE701 100V MYLAR 2200mfd@16V 1.39 4027 79 4511 1 95 JE200 5V 1 Amp Regulated Power Supply Kit $14.95 .001-.01mfd 4/.79 50V CERAMIC JE205 Multi -Voltage Board Kit (Adapts to JE200) 12.95 .022mfd 4/.89 lOpf-.022mfd 4/.59 4/.99 .047mfd 4/.69 JE210 5-15V / .5-1.5 Amp Regulated Power Supply Kit 19.95 .047mfd CONNECTORS 4/1.19 4/.79 (for JE610) 9.95 .1mfd .1mfd JE212 Neg. 12VDC Adapter Board Kit .22mfd 4/1.29 JE215 Adjustable Power Supply Kit (Pictured above center) 24.95 JE300 Digital Thermometer Kit 39.95 39.95 MICROPROCESSORS JE305 Solar Cell Panel Kit Z80A CPU (4MHz) 13.95 3E600 Hexadecimal Encoder Kit 59.95 1173AN-1 3OTune Musical MPU Chip 8.95 JE610 ASCII Encoded Keyboard Kit 79.95 CPU 6.95 JE701 6-Digit (.300") Clock Kit (Pictured above right) 19.95 8212A8 8 Bit I/O Port 3.95 DB25P D -Subminiature Plug 3.95 4 Clock Kit (Pictured above left) 14.95 8216 BI Bus Driver 4.49 4.95 JE730 -Digit (.357") -Directional DB25S D -Subminiature Socket 29.95 2513/2140 Character Generator 12.95 DB51226 Cover for DB25P/S 2.25 JE747 6-Digit (.630") Clock Kit Function Generator Kit (Pictured below right) 19.95 8T97 Trl-State Hex Buffer 2.25 22/44SE P.C. Edge 2.95 JE2206B AY -5-1013 30K Baud UART 6.95 UG88/U BNC Plug 2.19 AY -5-2376 88 -Key Keyboard Encoder 11.95 Jack 3.95 UG89/U BNC GRAB BAGS 2114-2 4K Static RAM (200ns) 3.95 UG 175/U UHF Adapter .59 MK4116 16K Dynamic RAM (25ons) 3.95 GB100 Ceramic Disc. Capacitors (100) $2.95 S0239 UHF Panel Recp. 1.49 5.95 G6101 Mylar Capacitors 60) 4.95 2708 8K EPROM P L258 UHF Adapter 1.95 2716 16K EPROM (+5V) 9.95 P L259 UHF Plug 1.95 GB102 Electrolytic Capacitors )60) 4.95 UG260/U BNC Plug 2.39 GB103 Tantalum Capacitors (40) 4.95 ÚG1094/U BNC Bulkhead Recp. 1.49 GB107 Silicon Diodes (1N914/1N4148) (100) 2.95 G8108 TTL Series Integrated Circuits (50) 4.95 Function Generator Kit G8109 Lines, Integrated Circuits (30) 4.95 Provides 3 basic Illem LINEAR lee G8110 Assorted LEDs (100) 5.95 waveforms: sine, GB113 Miniature Trimmer Pots. (30) 4.95 LM301N. .59 LM7805T . . 1.75 triangle and square GB116 1/4 Watt Resistor Assortment (200) 2.95 LM305H. 1.39 LM7812T . . 1.75 wave. Freq. range 2.95 .75 LM7815T . . L75 GB117 112 Watt Resistor Assortment (200) LM307N. from 1 Hz to 100K LM308N. 1.19 LM380N. 1.49 GB120 Miniature Slide Switches (25) 3.95 Heat 3.95 Hz. Output ampli- LM309K. 2.25 LM384N. . . 2.49 GB123 Sinks Assortment (30 Transistors Plastic/Power (100` 3.95 from 0 LM310N. 2.69 LM555N. . . .69 GB127 tude volts GB137 Chokes, Coils and Inductors (50) 3.95 LM311N. 1.49 LM556N. . . 1.49 to over 6 volts GB139 3-8 Terminal Solder/Screw Type (40) 3.95 LM317T . 2.29 LM565N. . . 1.95 (peak to peak). GB140 Spacers, Standoffs, Insulators (150) 2.95 LM318N. 2.95 LM566N. . . 1.95 Uses a 12V supply GB141 Washers and Spacers (200) 2.95 LM319N. 2.95 LM567N. . . 1.79 On (100) 2.95 or a ±6V split sup- LM320K-5 , . 2.25 LM723N. . . .79 GB145 Lugs, Crimp GB147 Hardware etc. ply. Includes chip, LM7905T 1.75 LM741N. . . .65 Mk - Nuts, Screws, (500)5.95 1 Assortment (100 2.95 LM7912T 1.75 LM1310N . . 2.95 GB154 & 2 Watt Resistor P.C. Board, com- 6.95 LM7915T 1.75 LM1458N . . .99 GB162 7 -Segment Displays (50) ponents & instruc- 10.95 LM323K. 5.95 LM1488N . . L59 GB165 Toggle, Rocker, Push Button Switches (40) tions. LM324 N. 1.29 LM1489N . . 1.59 GB173 U Teat & Sort 3/8" Potentiometers (100) 5.95 1 3 (Diodes) (100) 3.95 LM 337T . 2.29 LM1800N . . 4.49 GB175 & Amp Silicon Rectifiers LM339N. . . 1.29 76477N 3 95 08177 Shrink Tubing - Assorted 1" pieces (200) 3.95 JE2206B ....$19.95

CIRCLE 71 ON FREE INFORMATION CARO

www.americanradiohistory.com SUBSCRIPTION TV KITS SUPER SALE Govt. SURPLUS UHF Gated Pulse Kit.$39.00 ELECTRONIC UHF Sinewave Kit... $37.00 EPROM Kits include parts, manual 1-7 8 up 50 up EQUIPMENT and etched pc board. 2716 4.15 3.90 CALL 2732 9.70 8.85 CALL CATALOG Informative Catalog.. .$2.00 16K RAM EXPANSION KIT New ITEMS ... New BARGAINS! For TRS-80 Model III UPON REQUEST! J &W ELECTRONICS Set of 8 pieces U PD416-2 (200nS) FREE Send today for FREE copy of P. 0. BOX 61-B Data furnished with purchase on request. $13.95 NEW CATALOG WS -82 Address: Dept. RE CUMBERLAND, RI. FAIR RADIO SALES 02864 WRITE FOR FREE CATALOG 1016 E. EUREKA Box 1105 LIMA, OHIO 45802 = SUNTRONICS CO., INC. 12621 CRENSHAW BOULEVARD LONG -PLAY cassette recorder, 11/2 pounds, with WRITE FOR HAWTHORNE, CALIFORNIA 90250 -.A ,LOCATED NEXT To LOMA/ A INTERNATIONAL, two slow speeds for recording up to 15 hours on V STORE HOURS: Non At, tOem to 830,-5.f 10an,f .r. IN a single standard C-180 tape! ,_MCGEE'S CALIFORNIA OUTSIDE CALIFORNIA TOLL FREE Unbelievable sen- (213) 644-1149 1-800-421-5775 sitivity and voice fidelity. Takes telephone re- Mail Order-M,nimum Order. $10 Send Money Order or Check to' cording and voice activator accessories. Perfect SPEAKER & ELECTRONICS CATALOG P.O. BOX 1957 -Dept. R. HAWTHORNE, CA 90250. Use your for professionals, students. security personnel. VISA or Mastercard {please Include expiration date). Add 52.00 Excellent for radio and TV, security monitoring. 1001 BARGAINS IN SPEAKERS postage and handling to order. Carlfornia resIdents add 6% sales tax home surveillance, lectures. Free brochure. EX - TENDO Tel.: 1 (816) 842 5092 -TAPE SYSTEMS, Box 16000LC. Temple Terrace. FL 33687 1901 MCGEE STREET KANSAS CITY, MO. 64108 ADVANCED technological devices. Computer to FREE Flyer! Electronic IC's. REVERBERATION for organs and keyboards components. LED's, human brain interfaces, talking watches, satel- - etc. Send SASE to SYSTECH, Box 18905, San Simply connected to any electronic organ, even lite home earth stations, lasers and many more Jose. CA 95158 those with multiple outlet channels. Room size amazing products. Send $2.00 for catalog to and reverberation time adjustable. Nothing com- MICROWAVE TV units complete-1 year warran- TECHNOTRONICS, PO Box 2643, Winter Park, parable in this price range is offered on the ty. $150.00. MEC, Box 3123. Tempe. AZ 85281. FL 32790 market. for free Send brochure. DEVTRONIX OR- Dealers Wanted. CAR stereo graphic equalizer amplifier. 110 GANS, INC., Dept. 60.6101 Warehouse Way. Sac- watt. 7-band equalizer. with LED power meters. ramento. CA 95826 POLICE scanner owners attention: Police 10 code, fire department code. Send $4.00. ROBERT Factory fresh and pretested, $45.00. Free ac- SATELLITE Buffs: used 6. 10. and 16 ft. parabolic TURRIN, P.O. Box 1562. Clifton. NJ 07011 knowledgment of delivery. Send money order to antennas for sale. Muchmisc. Call days: (216) J. COOK, 1381 North Sereno Circle, Bountiful. 871-5552; evenings (2161779-8539. FOR sale -TV -VCR shop test equipment and in- UT 84010. Plus $2.70 shipping. ventory. RCA. Zenith. GE. Philco modules and MICROWAVE and other TV equipment. Catalog parts. Bargain price. Send SASE for complete BOB'S TV does it again! Six hour VHS taps only 20c. manual $1. TROJAN ENTERPRISES, 2920 list. DON DEMARCO 5687 Billmyer. Tecumseh. $130 for a box of ten. BOB'S TV, 93-15 86 Drive, Shelby. Indianapolis. IN 46203 M149286. Woodhaven, NY 11421 TERMINALS 8'2 COMPUTERS COMPONENTS 74 S00 74500 39 745138 75 74502 45 745140 *ADDS* CSOROC ATARI° 800' 5117400N 18 54574625 30 oc .c. 74503 5N7402N 22 SN749211 49 38 745158 75 74504 745174 - 5//74049 21 45 39 35 VIEWPOINT - MASTER 55719345 74506 5N7108N 22 SN 7495N 50 39 745175 1 35 COMPUTER SYSTEM 74510 SN 14106 16 597/98N eo 39 74S182 75 74515 45 745189 $ 58.85 55741 210 20 SN741225 39 4 25 74520 400w/16K $350.00 5457413N 22 SN 741365 95 55 745201 6 75 74522 CARDS SH 7414N 29 5N74141N 69 55 745240 2 75 74530 75 745244 NICROSOF7 800w/16K $699.00 S974166 27 5H74151N 65 2 95 74537 55 745251 511741 71.1 29 S974153N 56 2 75 280 SN74209 17 SN74154N 25 74550 65 745287 295 - *800 Computer w/48K 74551 49 74S288 IQ $29500 SN7425N 20 54474155N 75 296 SN7430N 17 5974157N 58 74564 55 745299 5 75 and 16K 74574 745470 Cfr) RAM *Bg21v 59743711 28 5974160N 89 65 9 25 U x U $825.00 74586 96 745471 120 11.cur app 5N7438N 24 SN7/161N 155 950 Arm, * - - - SN7440H 18 5N74163N % 745112 95 745473 950 010E R w.eeee....eee...a SN74429 45 55741649 97 745132 145 745474 950 VIDEOTERM SN7443N 42 5N74165N 55 EPROM 00 ATARI PERIPHERALS: SN7445N 84 5974174N 88 $6:9.00 lk2O500 59745114 19 511741759 79 2708 3.25.. 8 NN 2.96.. Printer -825-- 65000 Asteroids 597454N 19 5N74180N 75 Disk Dr-810- 48500 MissleCom> 32.50 56747411 27 54574191 N 1 15 2718 5.50.. 8 94 5.00.. REAL-TIME CLOCK 59747511 35 5974393N 165 Record. -410- 8200 Sup Brk.Out DISKETTE CALENDAR (MSM5832) 2732 12.86.. 4 94 11.00.. Paddle (Pr) Assem. Edit.- 4900 74LS00 16.96 ..40( 4116 200ns. 8/ Meres.. I «SALE» Mono Metal D.t. CMOS C Joystick WO' Star Raiders -4500 741.500 28 741.5158 M1.502 28 741.5181 6.3 $1.85ea. $1420 Wabash: Nature 32k RAM- 17595 Basketball- 2800 741503 26 7415162 89 21141. 300148 275..41N 1.90 Tem. 160115, Dale. Year. .. 6 741.504 28 74L515.3 9e 200119 245e4 Moe 2.00.. 'Day of weak Basic Cart.- 4990 Chess -3200 51/4-810/ )41506 22 74 L5164 e5 'tw. 01,«ltw 741508 29 74 L5185 86 2111 450140 2.50..1094 2.00.. 741_509 741.5109 1 56 $24.90 'l at Dal. 898 * MONITORS* 741510 26 74L5170 175 MISC. centtl 8inch '1&1 Adora.. $745 741514 88 741.5174 85 2102 6/ SPEC 7 741520 22 7415175 85 /SONS .96 . R/w Hola 1103A .75 Sol« ZENITH1 1. Green Phos 74L521 26 74L5190 S S I SD :More Avail. as 8038 296 LF0765 teas 'Inter Signal XTAL 12in.15MHz. Hi -Res. $I18.50 74L526 40 74 L5191 1 25 NE566 27 rlgpe NM w,,, - 741.527 27 741.5196 96 AY5-1013A 4.25 59.47054 32 7681193 2.Hi- 741528 37 74L5197 78 1468 -86 QTY. PRICE AVAI .tai Contra $ 2.85 J.C.S. 2 s L8.111001 1.95 741530 29 74 LS221 1 1489 '5y Pow Sup 12in.18MH2. Hi-RRs. 168.50 -z 25 .95 TM54400 1.40 e; 74L532 31 74 L5240 1 65 8r26 130 Non glare 14C4006P 1.50 'Low Power AMDEKI] 741538 31 74 L5241 165 8726 130 DI.0p.tan Screen 6ep02e 1.56 SPECIALS 12in.12MHz. 741542 63 74 L5243 156 8212 1.96 00824 196 ZENITH ZVM 121 3.GreenPhos-8155.50 - 741543 77 74 L5244 156 6216 196 03001 196 13in Color Hi -Res 74L574 38 74 L5245 245 184106CR .85 0700? 1.96

I I 741575 111111 ModR Green "GLOBA s®® 3a Lo -Res -8375,50* 55 74 LS251 125 IT410TRMC .85 74L585 45 7415253 85 7906 .a6 1 Y /CI I.C. LPK-1: s®® 741590 59 7415257 a5 7906 .e6 IS 2,?»10112 74L593 85 74 LS259 196 7915 .e6 SOCKETS Logic Probe 741590 80 7415250 55 7918 .56 le SUM n 11QItlmlt41l 7415107 43 74 LS273 155 7806 .e6 i« p et $ 118.50 Kit - complete CONCORD 7415113 45 74 LS279 45 7806 .a5 8 10/1.20 nothing extra THE MPD 117 741.5122 45 74 L5290 1 25 7806 .86 10/5.30 14 10/1.30 8255 -i-$5.95 to buy. Min turns an ordinary 7419123 99 74 L5293 I e6 7812 .85 10/570 16 1011.40 pulse width outlet Into a cont- 7415125 89 74 LS366 85 MC1330A1P 1.60 10/1.70 18' 101190 8748-8 --$3 rolled power source COMPUTER 7ßL5126 79 74 LS367 75 MC1350P 1.15 1009.70 20 1012.10 300nsec. 74L5136 64 7415373 1 45 11C13558P 1.50 10112.0 22 142.70 7415139 59 74 LS374 1 45 LM360 1.10 10/13.70 24 10/2.0 3341Pc --$2.00 $18.95 179.50 14 L51S1 49 741.5377 1 25 14156685 .96 1X/4.0 28 10/3.00 74L5153 49 7415069 1 56 115741 .25 10/17.0 40 10/3.90 PRODUCTS 74LS157 69 7415670 1 es MC14581. .56 winynap *older MM5060 -ix 35e 1971 SO. STATE COLLEGE ANAHEIM, CALIF. 92806 Six

CIRCLE 73 ON FREE INFORMATION CARD

www.americanradiohistory.com ramMU the Erst name in Counters ! 9 DIGITS 600 MHz $129 WIRED SPECIFICATIONS: Range: 20 Hz to 600 MHz most versatile, feature packed counter available for less The CT -90 is the Sensitivity. Less than 10 MV to 150 MHz than $300.00! Advanced design features include; three selectable gate times, Less than 50 MV to 500 MHz CRICES nine digits, gate indicator and a unique display hold function which holds the Resolution 0.1 Hz (10 MHz range) CT-90 wire9I year warranty 5129.95 CT-90 Km 90daYWnawv- displayed count after the input signal is removed Also, a 10mHz TCXO time 1.0 Hz (60 MHz range) Amy 109.95 V. 10.0 Hz (600 MHz range) SCI ACis doper 3.95 base is used which enables easy zero beat calibration checks against W W Ad. Nkd pact +AC base input and Micro- Display 9 digits 0.4" LED OA.I svpo 12.95 Optionally; an internal nicad battery pack, external time Time base: Standard-10.000 mHz, 1.0 ppm 20-40°C. Orne 1. A1,cm power Oven power high stability crystal oven time base are available. The CT -90, me box 49 Optional Micro-power oven -0.1 ppm 20-40°C External urne bue input 14 .95 performance you can count on! Power. 8-15 VAC @ 250 ma

7 DIGITS 525 MHz $99 WIRED

SPECIFICATIONS PRICES: Range: 20 Hz to 525 MHz The CT -70 breaks the price barrier on lab quality frequency counters. CT-70 wired, 1 yearwarranty $99.95 to 150 MHz Deluxe features such as; three frequency ranges - each with pro- amplification, Sensitivity. Less than 50 MV CT-70 Kit 90 day parts war- Less than 150 MV to 500 MHz dual selectable gate times, and gate activity indication make measurements a ranty 84.95 Resolution: 1.0 Hz (5 MHz range) snap. The wide frequency range enables you to accurately measure signals AC -I AC adapter 3.95 10.0 Hz (50 MHz range) from audio thru UHF with 1.0 ppm accuracy- that's .0001%! The CT-70 is BP -1 Nicad pack + AC 100.0 Hz (500 MHz range) adapter/charger 12.95 the answer to all your measurement needs, in the field, lab or ham shack. Display. 7 digits 0.4" LED Time base 1.0 ppm TCXO 20-40°C Power. 12 VAC @ 250 ma 7 DIGITS 500 MHz $7995IRED

s provides most PRICES; Here a handy, general purpose counter that counter functions at an unbelievable price. The MINI -100 doesn't have the full SPECIFICATIONS: MINI -100 wired, 1 year warranty $79.95 frequency range or input impedance qualities found in higher price units, but Range I MHz to 500 MHz AC -Z Ac adapter for MINI - for basic RF signal measurements, it can't be bead Accurate measurements Sensitivity; Less than 25 MV Resolution 100 Hz (slow gate) 100 3.95 can be made from I MHz all the way up to 500 MHz with excellent sensitivity and AC 1.0 KHz (fast gate) BP -Z Nicad pack throughout the range, and the two gate times let you select the resolution adapter/charger 12.95 Display. 7 digits, 0.4" LED desired Add the nicad pack option and the MINI -100 makes an ideal addition Time base 2.0 ppm 20-40°C to your tool box for "in -the-field" frequency checks and repairs. Power. 5 VDC @ 200 ma

8 DIGITS 600 MHz $159 WIRED

SPECIFICATIONS PRICES: Range: 20 Hz to 600 MHz The CT-50 is a versatile lab bench counter that will measure up to600 MHz CT-50 wired, 1 year warranty $159.95 Sensitivity. Less than25 mv to 150 MHz with 8 digit precision. And, one of its best features is the Receive Frequency Less MHz CT-50 Kit, 90 day pails than 150 mv to 600 Adapter, which turns the CT -50 into a digital readout for any receiver. The Resolution 1.0 Hz (60 MHz range) warranty 119.95 adapter is easily programmed for any receiver and a simple connection to the 10.0 Hz (600 MHz range) RA -1, receiver adapter kit 14.95 receiver's VFO is all that is required for use. Adding the receiver adapter in no Display. 8 digits 0.4" LED RA-I wired and pre-programpre-program- Time base: 2.0 ppm 20-40°C way limits the operation of the CT-50, the adapter can be conveniently med (send copy of receiver Power. 110 VAC or 12 VDC switched on or oft The CT-50, a counter that can work double. duty schematic) 29.95

DIGITAL MULTIMETER $99 WIRED

The DM -700 offers professional quality performance at a hobbyist price. Features include; 26 different ranges and 5 functions, all arranged in a SPECIFICATIONS volts: 100uV to I KV, 5 ranges PRICES: convenient, easy to use format. Measurements are displayed on a large 31 DC/AC 1 $99.95 DC/AC DM -700 wired, year warranty digit, 1 inch LED readout with automatic decimal placement, automatic DM -700 Kit, 90 day parts current 0.1 uA to 2.0 Amps, 5 ranges polarity, overrange indication and overload protection up to 1250 volts on all warranty 79.95 Resistance 0.1 ohms to 20 Megohms, 6 ranges ranges, virtually The DM -700 looks great, a handsome, AC-I, AC adaptor 3.95 making it goof-proof! Input BP-3, Nicad pack +AC jet black, rugged ABS case with convenient retractable tilt bail makes it an impedance 10 Megohms, DC/AC volts adapter/charger 19.95 ideal addition to any shop. Accuracy. 0.1% basic DC volts MP-1, Probe kit 2.95 Power. 4 'C' cells AUDIO SCALER ACCESSORIES COUNTER PREAMP Telescopic whip antenna - BNC plug S 7.95 15.95 For high resolution audio measurements, multiplies High impedance probe, light loading For measuring extremely weak signals from 10 to 1,000 15.95 UP in frequency. Low pass probe, for audio measurements MHz. Small size, powered by plug transformer -included. 12.95 Great for PL tones Direct probe, general purpose usage Flat 25 db gain 3.95 Multiplies by 10 or 100 Tilt bail, for CT 70, 90, MINI -100 BNC Connectors 0.01 Hz resolution! Color burst calibration unit, calibrates counter Great for sniffing RF with pick-up loop 14.95 $29.95 Kit $39 95 Wired against color TV signal $34.95 Kit $44.95. Wired

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CIRCLE 69 ON FREE INFORMATION CARD 115

www.americanradiohistory.com Model A501 Power Amp Pure Class A 25W + 25W SAVE up to 50% on name brand test equipment. Switchable to Class AB 100W + 100W Free catalog and price list. SALEN ELECTRON- FUJITECH AUDIO KITS Switchable to Bridge Class A 100W mono ICS, Box 82-G, Skokie. IL 60077 Switchable to Bridge Class AB 300W mono Frequency Response 5-200KHz (-1dB) TELEVISION cable converters -video acces- Signal -to -Noise Ratio 120dB sories, discount electronic products and parts. LATEST AUDIO TECHNOLOGY Non-magnetic Chassis $1.00. ELECTRONICS ETCETERA, P.O. Box 826. "Out -board" comprehensive protection Solvang, CA 93463 FROM JAPAN circuitry DC circuitry with limited use of NFB POWER supply -12v @ 1 amp +12v @ 2 amps High Efficiency Fluid Convection Cooling Sv @ 1.5 amps +24v @ 3 amps. All fused. Used THD under 0.007% 16 X 7 X 51/2 encased, molded plug. ppd. Amplifier $21.95 Model A1033 Integrated Tube Perfect for disc drives. F. P.O. Design G. STEVPENS CO., Latest Japanese Box 781. Norwalk, Distortionless Output Transformer using CT 06856 special winding techniques TEKTRONIX 585, three plug -ins. cart, 105 gen- Most circuitry on PCB for easy assembly erator, $695.00 lot. (813) 494-3118, P.O.B. 1823, and bumf ree performance Arcadia, FL 33821 Output 30W x 2 Ultra Linear (Switchable to Triode) BOOTLEGGERS Bible for CB modifications 15W x 2 Triode Output $12.95. CB Radio Repair Manual. $8.95. Linear (near class A performance) Planbook $11.95. Also kits. complete units, and THD under 0.4% more! Catalog $1.00 at: A.P. SYSTEMS, POB 263 Frequency Response 30^30,000 Hz (-1dB) RE, Newport, RI 02840 Separate Pre -Out and Main -In KIT ONLY SYNTHESIZER module. PLL, 100 continuous di- $499.00 rect binary coded channels at 10 KHz steps. 38 MHz out; with schematic, specs, application notes. Send $9.98 ppus to PRESTON, 7 Doris Place, East Islip, NY 11730 SPEAKERS by Electro -Voice and others. Build your own speaker system and save. Also micro- Model A502 DC Stereo Control Center phones. mixers. amps. etc. Free list. SONIX CO., Direct DC coupling from Input to Output Box 58-RE, Indian Head, MD 20640. Phone (301) DC servo circuitry 753-6432. Cascade FET Input in all stages ENJOY commercial free television. Separate Moving Coil RIAA amplifier Experi- Distortion below 0.005% (3V) mental frequency control module is the finest Max Output 15V available today. Sine wave or gated pulse in kit or Frequency Response 20Hz-20KHz ±0.2 dB factory built. Information package $2.00, refund- Maximum Phono Input able on first order. LEE-TRONICS, P.O. Box 253. MC = 16mv RMS (1KHz) Taylor. MI 48180 MM = 270mv RMS (1KHz) $499.00 Built-in Headphone amplifier ATARI, Commodore computers, accessories. Relay Output Muting KIT ONLY software, lowest prices, information $1.00. (714) Send $5.00 for each assembly manual, $349.00 783-0556. SPORT 'N' SOUND, 21999 Van Buren. refundable with order. Grand Terrace, CA 92324 Monarchy Engineering, Inc. - - ew. UHF sinewave converters: complete kits 380 Swift Avenue, Unit 21 A A $175.00. etched/drilled PCB $25.00, UHF varac- . _ - . South San Francisco, CA 94080 "?'.1 tor tuner $40.00, toroid kit $7.50. MC/VISA -IA . . . . . accepted. Information $1.00. (714) 783-0556 Visa or Mastercharge acceptable. SPORT 'N' SOUND, 21999 Van Buren, Grand Ter- $349.00 race, CA 92324 SATELLITE system, $1950.00. Complete receiver P.O. BOX T0.2 kits available. WESTCOM, 715 Washington. Ayden, NC 28513. Dealers welcome. GARLAND, TX. 75050 40 LULLET ELECTRONICS (214) 278-3553 THE Tranny Caddy-tough, roomy lightweight carrying case for tools. components. PCB's. SEE SPECIAL WINTER Sound Effects Kit $18.50 Doorbells etc, -full details: MHP Co., Room 1042. 485 Fifth PRICES BELOW Avenue. New York, NY 10017. The Super Music P.O. Board Material. Free Info. BOYD 1 genera. Designed around ELEC- the new T.r Instrumente Maker TRONICS, 1998 Southgate Way, Grants Pass, Sound CherCherSN76472 board provisos banks of MINI REVISION 2 OR 97526 DIP swathes and Sots to program he rn $Z495 h,nal Ionsvlt the SLF Osclllaalor (Basic Kit) ' C . 0 uSO. Noise. One Shot an a \ Car Horn. not lncrutle speaker Envelope Controls A OuadOp Does / Toys 30 CHANNEL ample rs used io enant swathes or 2708 ROM an Adwstable Pulseo Gene,. CABLE TV tor LevelCompare., ana Now you can play hundreds of songs using the Bullet Super Music Maker. The unit features a u ltiple Dscalator for even single factory CONVERTER 3 . 5' programmed microprocessor IC that comes with 20 pre- 0 Pc eoaroaeatures a prototype programmed short tunes. By adding the additional PROMS area I tor added (2708's) the system can be expanded to play up to 1000 ...try Ease notes per PROM. Just think a compact electronic ORDER No. 171AE047 to dupnca,e Explosions. instrument that will play dozens, hundreds or even 0 Chasm Guns, Steam Tnlns, or Thousands of selections of music. The kit comes with all `!I ROUTE 9N, r of electronic component. (leas the PROM), and a drilled, PLATTSBURGH, N.Y. 12901 elh., ast vine me until has a plated and screened PC Board which measures 4" x 43/4". multIPle of CPpnans The Tel.: (518) 561-8700. low once in u parts The 7 watt amplifier section is on the same PC board and drives an 8 ohm speaker (not included). from a whisper to assembly man programming charts ana detailed 76477 ch,p ear splitting volume. Since the unit works on 12 VDC or 12 specllicahons It runs on a 9V batter), (not in di On hoard VAC , vehicle or portable operation is possible. Whet do 100MW amp will drive a sins i speaker Bile e unit can b; EDUCATION & INSTRUCTION connect. to you, stereo crediblecresuls' (Speaker n you gel for $24.957 Everything but a speaker, tran.lonner, 0 Included) 76477 Is IncludedWAvertable separately for 43.15 each cue switches and PROM. Additional 27 a albums containingprrpopularwn are available for rmati each uded UNIVERSITY degrees by mall, Bachelors. Mas- can programyour own PROMS avngbleor OMalbums are Ì ters, Ph'D's .. Free revealing with the kit instructions LetsniavertablecROM albums are details. COUNSEL- 7 Watt Audio Amp Kit $6.95 availableot n. tpos:iblenit playaelectronic r ING, Box 317-RE5. Tustin. CA 92680 SMALL, SINGLE HYBRID IC AND COMPONENTS FIT ON A2" note at a time.y, It is not possible f0 play cho/dschords o/ a melody with harmony ºrtr esDe/ca x 3" PC BOARD (INCLUDED). RUNS ON 12VDC. GREAT FOR 0 ANY PROJECT THAT NEEDS AN INEXPENSIVE AMP. LESS Envelopeoar control gives sing to notes. On board inverter allows single voltage ! 012) operation. d THAN 3% THD @ 5 WATTS. COMPATIBLE WITH SE -01 OPTIONAL ACCESSORIES Be an FCC LICENSED SOUND KIT. DIP Switches (One One 5 dpos.)to ucos) 1 Electronic Technician 0 (Can w soldered to PC Bd. to access tunes) RaoiorPH E4 Doomsday Alarm Rotary Sr Two n on 2) lest Earn up to $600 a Week & More! Kit $9.95 (For remote wiring to PC Bd. to access tunes) No costly School - The Original FCC Tests. It you have trouble sleeping and you would like the rest of Anracthe Tan Caw 6.50 Answers exam manual that prepares you al WMlplug oetonneoatior 3.00 home for FCC General Radiotelephone License. the neighborhood to share your misery then this little kit 117VAC (For operation on house voltage) Newly revised multiple-choice exams corer all `- will be for you! There is no way to accurately describe the 3--- ': ...- SPECIAL WINTER PRICES areas tested on the actual FCC Govt exam! howls. tones that Unearthly screams and come out of this t Super Music Maker with case and two 5-poarrion rotary revious ex ulred 512.95 postMIODUCTIORSCOMMARD+ kit Four separate tone oscillators are mixed, cancelled swrrcnes $32.00 paid Moneybacperiencek Guarantee and stepped at a varying rate. 10 Watts of crazy sounds. A 2. Super Music with one 2718 20 X e PROM filled with Dept. E _P -O- Box 26348, San Francisco, CA 94126 over 50 selections of additional music notes) great fun kit or a practical burglar alarm. Complete with ( 1500 $32,00 3. The Whole Ball 01 Wax! 02 PC board and all necessary components less speaker. For case and switches. $39,95 ATTENTION 6-t2 VDC. ORDER DA -02. ELECTRONIC TECHNICIANS ORDERING INFORMATION: 0. seat 3TZ Time Zone Clock Kit Call or Write For Free Catalog Highly Effective Home Study BSEE Degree Pro- gram for Experienced Electronic Technicians Microprocessor/ROM clock kit keeps local tinte (12 hour COD MINIMUM lu0.00 ADD 52.50 FOR COD'S Our New Advanced Placement Program grants UPS DELIVERY ADDRESS MUST ACCOMPANY ALL format), 2 world time COD and zones (24 hour format); Large ORDERS Credit for previous Schooling & Professional Ex- 6" ORANGE readouts 10 min. ID timer for HAMS. Comes $1.00 HANDLING ON ORDERS UNDER Stete perience. Advance Rapidly! Our 36th Year! complete with attractive plastic case and wallplug XFMR. VISA, MC CARDS OR CHECK ADD 5%FOR SHIPPING FREE DESCRIPTIVE LITERATURE! 6 Digit (hrs.. min . sec.) Ouant XTAL Timebase TEXAS RESIDENTS ADD 5, STATE SALES TAX 3 Time Zones (Selectable) Bauery backup Institute of Electronics Engineering ALL FOREIGN ORDERS ADD 25Y, FOR SHIPPING Cook's Feathertouch Iront panel Quality solder masked and (CANADA 15x,) NO FOREIGN COD'S DESK 15 . P.O. BOX 20345, JACKSON, MS 39209 swiiches plated PC boards CALL (214) 275-3553 TO PLACE CREDIT CARD OR COD Seconds Reset/Hold feature $54.40 ORDER 4.

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www.americanradiohistory.com (Wiz) Lbb-:1/btS (602) 266-:J/5tS EDUCATIONAL HITECH KITS FUN TO BUILD AND USE E

ELECrRO LCD Multimeter 0-3511 1.5A Quality The affordable LCD Multimeter. High accu- Power Supply CB RADIO patios" racy 19 range large 30 digit DMM with Provides 4 ranges of current range! Frequency diode test, auto polarity and LO Batt. limdmgupto1.5A.Usespre- GET more CB channels and elk SURPLUS -/e indicator. cislon regulator and power Expanders. boosters. speech processors. FM Model 101 Fully Assembled $89.95 vansistor booster. converters, ignition noise blankers, how-to 6835 North 16th Street , HKlT-83A Kit $19.50 books, plans, modifications. Catalog $2. CB CITY, Box 31500RE. Phoenix, AZ 85046 Phoenix, Arizona 85016 0-50V 3A Regulated Adjustable Power Supply With overload protection and LED **TV BOX BUILDERS** power on indicator. Assam $28.50 COMPUTER ACCESSORIES HKIT-503 Kit 024.50 LM 7812 . . . 51 .35 LM 301 $ 90 LEMON -AID Loader. Plug in. Ends touchy cas- 30W Single Channel Power Amp. sette loading TRS-80. Guaranteed. $12.99 post- LM 7815 ... $1.15 LM 1458 51.00 Lcmpact power amp with volume, treble and base control. Excellent for boosting the paid. WAYNE LEMONS TECH SERVICES, PO 78L15 $1.05 LM 380 $1.90 power of your portable radio, o cassette Box 429. Buffalo, MO 65622 1417) 345-7643. Connect to your TV audio and experience the LM1800 . . . . $2.45 NE 565 $1.90 real sound of your TV program. HKIT-300 Kit 016.95 LM 1889 . . . . 52.75 MC1330 . . . . $2.40 MC1350 $1.90 Programmable Music Door-bell CABLE Electronic door -bell that has 9 programmable tones. POLYETHYLENE DIELECTRIC 74123 $1.80 MC1358.... $2.10 Uses CMOS for low power consumption and has auto'shut-off feature. RG213 noncontam inat ing 95% shield mil spec .. 36c/ft. HKIT-47A Kit $14.50 RG58AU stranded MIL -SPEC 12c/ft. RG8U 95% shield MIL SPEC.. Sic/ft. CH3/CH4 Modulator LOW LOSS FOAM DIELECTRIC 5 Function LCD Pen Watch RG8X (mini 8) 95% shield 17c/ft. High Quality ball point pen with built-in 5 RG8U 97%shield 30c/ft. function LCD watch. Comes es finished RG58U 95% shield 10c/ft. product only with gin box. 09.99 RG58AU stranded center 80% shield 11c/ft. RG59/U 100% foil shield TV type 10c/ft. Rotor Cable 2.18 ga 6-22 ga 19c/ft. 7 DI R C 8 K Style Toggle Switches Cable -shipping 53.00 1sí 100 ft., $2.00 each add"' 100 ft. H Universal Counter DPDT ON -OFF -ON $2.00 DPDT 0N -OFF $1.60 CONNECTORS Universal Counter counts up -ON PL.259 to 60 MHz and 10 million SPOT ON -OFF $1.40 & SO -239 10/15.89 ants. 7 large 0.5" digits. SPOT ON-OFF $1.10 Reducer UG-175 or 176 10/$1.99 Crystal time base. High per. UG-255 IPL.259 to BNCI 53.50 formance. Connectors -shipping 10%add'I. 51.50 minimum HKIT-B5A Kit $49.50 32.768 Wiz Xtal $2.50 FREE CATALOG Function Generator We also specialize in high quality COD add 51.50- FLA. Res. add 4% Sales Tax Generates triangle. square or sine custom PCB manufacturing. 9 V. BATTERY CLIPS wave. 1 Hz to 100 KHz. Ideal for Please send inquiry. testing audio amps. MENIAL ELECTRONICS n HKIT-55 Kit $35.50 Kits do not include xfermer/batt./case Dept 42 .Y 5685 SW To Order, send check or money order to' 80th Street, Miami, FL 33143 W/9"LEADS 1,1111114 Call (305) 661-5534 Hitech Electronics 8/$100 4425 W. Sepulveda Blvd.. Torrance CA 90505 Phone Orders: (213) 371-2160 VISA and M/C welcomed. Minimum Order $9.00 UHF VARACTOR Shipping and Handling $2.00. CA resident add 6% tax. PLEASE VISIT OUR STORE. open 10.00.6:00 Mon. thru Sat. TUNER Special discounts available to educational institutions. Dealer inquiries invited. 51795 CIRCLE 85 ON FREE INFORMATION CARD 15-24 V. 0001201:0200200200000000000000000000 0 0 e INTERTELL Minimum Order $9.00 0 O CHANEY Please include 51.50 for shipping (UPS) PHONES We accept VISA and MASTERCHARGE 0 Itronicss inc.1 EXTRA FAST SERVICE 0 Model 2160 0 eiec 21 Button 0 P.O. BOX 21038, DENVER, COLO. 80227 PHONE ORDERS: 303-781-5750 0 W/Intercom 0 0 O TEACHERS AND HOBBYISTS - 0 jp cnanweu..liái,voéérnimo°..rióy«°."'="wrewn'a'me na enea Q tñaosaease.cc.tea wu. ocore sou,:esatoe ºnos5n. e l cu s .ex,r meta ºa^alp" CMMy Dec ".:%,aDullaan giofwruncontun.awiayetcheden°,,3 wºlas.po aeceuse,aeyan,no,ou na eeepnw w,he1 ar.oper aaeembh,neY wars Ina ell eiwlronlc 10 $2e 0 nweery pans Ie.cept es roled on a Nw tint ana eeaY unaennna 1nt I,me it veu nave anyh0uew owl pieew cut or wore. caw Mre to aural you eeeemPly inetruclens. ou pro.gee s.neryfor the senryooenlwscsena lla.e,.a you may 4 SEND FOR OUR COMPLETE CATALOG OF KITS AND PARTS. 0 MULTI -VOLTAGE 120VAC VARIABLE STROBE UGHT KIT ELECTRONIC WHEEL OF FORTUNE KIT s 0 complete variable rate strobe light kit produces bril- (, Push the start button and a bright red ball (LEDS) rowA O SWITCHING giant flashes of light, Operates from standard 'J appear to spin around ten numbers. When you release B 8 0 0 120VAC. Reliable design -thousands of these are the butt on the electronic ball appears to slow down -e- ?aa4 POWER SUPPLY in use throughout the world. Overall size of corn- and finally comes to a stop on one number. As the ball ' 0 pleted board: x 2"W x 3"H. 0 31 spins a small speaker emits a ticking sound in synchronization. Unit 834% 0 C3071 $7.50 operates from 9V battery. Size of board: 2.9" t 2.6". C3806 59.99 0 3VDC ELECTRONIC WARNING FLASHER KIT AC FAILURE ALARM KIT V.A.C. +5 +12 +24, & +46 INPUT 110 OUTPUT -5, -12, 0 This portable battery operated device continuouslyJ.-Arr.. -t. Have you ever been late because the AC went off and your clock radio 0 emits bursts of intense light at a fixed repetition didn't work? Well, that need not happen again! Sim - 0 rate. Can be seen for great distances making it a " ply plug this unit into the wall outlet and if the AC great safety device. Features xenon flashtube.Oppeerates -. a tone. Features HMR II* goes off the and emits green ....--...7,,.. 0 on 3VDC (two t.5V Batteries). Size of board: 21/21 x 2"W. ready light and piezoelectric tone device. Oper - 0 C3207 $7.95 ' ates on 9V battery. Size of board: 2.8" x 2.3". C4483 $4.75 0 0 STROBOSCOPE KIT 6 MO. WARRANTY 10 WATT SIREN KIT 9enable IC design kit for use in physics experiments or -- G Kit provides a loud alternatingtone output. Uses two IC's and a power troubleshooting. Optically stops motion of fans, , - ri transistorontrl o a Ceopea performance.n.Requires Features variable sound 0 wheels, pullys, flywheels, etc. The stroboscope 0 control and 6 to 12VDC operation. Requires 8 ohm HAM MICROWAVE RECEIVER operates from standard 120VAC and features bright speaker. Size of board: 3.5" x 1.5". 0 xenon flash tube and IC design. Size of board: 3.5" x 4.75". 0 w/Cable & Power Supply C4068 $5.00 O C4070 $29.95 " 9- PHOTO SLAVE TRIGGER KIT SOUND EFFECTS GENERATOR KIT 0 Probably the most sensitive slave trigger kit on o ,e Exciting sound effects kit uses the popular TI76477r p S the market. Simply connect to the strobe that will `. chip to develop phasor, locomotive. siren. tweeting 0 be used as the slave. When the master strobe bird, organ, Model T. etc. sounds. Uses dip switch - --'w 0 is fired the slave strobe also flash. r for simple programming $149x5 will Size of I: 15 of the generator. Operates r4,( 0 board: 1.5" x 1" '-- from 9V battery Size of board: 3.25" o 2". y-jg, - 0 ORDERING 0 C4630 $6.00 1 - C4422 $12.95 0 FASCINATION STAR KIT PHASOR GUN SOUND AND LIGHT KIT INSTRUCTIONS Produces "exploding Minimum order $10.00 an visual effect using [ a O star" 25 .: . 4 Here's simple kit which makes an excellect first project. Uses special 0 Payment money and IC circuitry.The center LED lights first then .111-,..:e .¡ IC. dadington transistor and LED to produce C.O.D. by cash or order, the next company check. LEDS group of LEDS light and then another set of ' "outer space phasor gun" sound and flashing i e until the outer edge of the star lights up. The _ red light. Operates from 9V battery. Size of D eslightsprocess then reverses itself. Operates 9V bat- 1.2". C.O.D. - $2.25 + $2.35 shipping. from el board: 1" x áx CREDIT CARDS - Master Charge & Visa. 0 tery. C4432 $10.95 C4484 54.00 0 SHIPPING MINIMUM $2.35 + 35C per $100.00 SEQUENTIAL LED FLASHER KIT [4911461:::423 EL COLOR ORGAN for insurance. This kit combines IC circuitry and 10 jumbo red Very popular 3 channel color organ causes lights of your choice to LEDS to produce a unique visual display. LEDS flash to beat of music. Features level controland 3 .% e *We do not sell these items for the use of continuously light sequentially from right to left. Easy to separate AC outlets to connect Christmas lights, kit.Operates from 9V battery. Size of board: 5.25" o 1.5". lamps,etc. Operates from Size of board: e+M..I receiving type TV transmissions. build \- subscription ó 120VAC.

CIRCLE 78 ON FREE INFORMATION CARD 1200000000191212 000000000° 00° ° 2LICIL19 LI 118 CIRCLE 76 ON FREE INFORMATION CARD

www.americanradiohistory.com SURPLUS ELECTRONICS CORP. ii... WHOLESALE/RETAIL EQUIPMENT/COMPONENTS/WIRE & CABLE/ACCESSORIES r_ dr-Lgl 7294 N.W. 54th Street We accept MasterCard and Visa. Phone: (305) 887-8228 Miami, Florida 33166 TWX: 810-848-6085 "TANK BATTLE" TV GAME C.B. SPECIAL

t a # In just a short time and with a few minor parts, the most CONVERT THESE TO 10 METER FM , novice hobbiest can complete this exciting Tank Battle New HYGAIN printed circuit board assembly with PLL02A Create a fun -filled evening for the whole family. => chip and 3 crystals. (Squelch pot, volume control and Two independent tanks rumble thru land mine fields, channel switch not included.) Boards sold as is, the way we gameshoot shells and fragment when hit. Four distinct engine bought them from the manufacturer. Board dimensions sounds are produced for the different speeds. Sounds of Ç r 6"x 61(' gunfire, shell bursts and tank explosions are realistic. att gip. A Automatic -screen scoring. Supplied schematic on with 1-9 $7.50 50-99 $6.00 drawing. s 10.49 $6.50 100 -UP $5.50 SOLD AS IS $9.95 ea. '

COPPER 9 VOLT NiCd WHISTLE 1, - _ COMPUTER GRADE ELECTROLYTICS CLAD BOARD RECHARGEABLE ACTIVATED VOLTS DIAM-/LOTH. PRICE SWITCH . .4 CLADVALUE/MFD(Double Side) ' 1 BATTERY : III 63,000 @ 15V 3" x 51/2" $4.00 ea. Size 9.25 x10.75 $2.50 ea. 10,000 @ 20V 11/2" x 53/4" $3.00 ea. Thickness .062 NEW. Replaces 2,700 @ 25V 11/4" X 21/4" $2.00 ea. thepopularaV Your whistle from a distance of 30' max. is $2.00 ea. TransistortorrB Battery. pickedpu b y an FET condenser mic. which 2,900 @ 25V 11/4" x 2" $2.00 ea. turns on the switch. (Sensitivity can be 100,000 @ 30V 3" x 51/2" $6.00 ea. ERIE TRIMMER CAP adjusted.) Match your whistle again and $4.75 ea. turns off. 39,000 @ 30V 1" x 53/4" $4.00 ea. 513-002 Schematic Diagram Supplied @ 30V 3" x 5 /2" $3.00 ea. .196" Din. .080" High MAHOGANY34,000 3.5.2Opf PROJECT BOX 450 75V 11/4" x 21/4" $2.00 ea. a¡ Scec1POWER @ Yf' 500 100V 11/2" x 31/4" $2.00 ea. $.75 ea. $1.50 ea. TRANSFORMER @ i - ea. SMALL ENOUGH TO FIT 50 @ 450V 11/4' x 2" $2.00 ti , $14.95 ea. I IN YOUR WATCH j -- >I 14 ,1Ì 1 Primary 115 vac 0 AXIAL LEAD SPEAKER AMP METERS Secondary -32 v with ,! ELECTROLYTIC-- 4s/a"wx7/'Ix3'4"to1/z"h 24 v tap at 15 amps CAPACITORS 3" Diam., - Has a lip for recessed face Dim. 41h" h X 33/4" w X 4" deep 8 OHM, / 2 uF @ 15V 12/$1.00 plate and a felt bottom 5 Watts. I 10 uF @ 15V 12/41.00 $2.50 ea. SCREW DRIVER KIT SOLID GEL BATTERY ['.'L 6 volt @ 8 a.h. with Charger 20uF@ 15V12/$1.00 50 uF @ 15V 12/$1.00 $2.00 ea. $14.95 2.2 uF @ 25V 12/$1.00 21/4' square, no shunt required. Handle stores four blades 3.3 uF @ 25V 12/$1.00 POWER SUPPLY 1 uF @ 35V 12/$1.00 Easy -to -read dial. 2 single slot 5/32" Si 3/32" Elpower EP 680 may be charged con- 2 uF @ 150V 12/$1.00 $3.95 ea. Movements: 0-6, 0-10, 0-17 1 Phillips 1 scratch awl stant voltage or constant current. Bat- 6" long with one blade tery.ia self-contained and requires no 25 uF @ 25V 15/$2.00 + 12 Vitt .1 amps maintenance. Connections made 3 50V - + 5 vdc .4 amps COAX CONNECTORS inserted $1 with uF @ 15/52.00 v 00 ea- quick connect lugs. All plastic case size 5 uF @ 50V 15/52.00 51/2 h x 23/4 w x 41/2 I, weight 4 lbs. UG-273/U BNC-F/UHF-M $2.50 SUPER SMALL 10 uF @ 50V15/$2.00 r. UG-255/U BNC-M/UHF-F $3.00 uF @ 25V 10/$2.00 PHOTO FLASH TELEPHONE 8. TTY 250 UG-146A/U N-M/UHF-F $4.50 170 MFD 330 VOLT INTERFACE MODEM $4.50 MFG by Anderson Jacobson SUBMINI 10K POT 11/4"x z/e" DM Modem Model DC 230 with A-36 UG-175 RG -58 Adapt $ .20 I i.'.--,,-'rte E. F JOHNSON Telephone Coupler with On -Off UG-176 RG -59 Adapt $ .20 2 for $1.50 w 1/4" hole mount, "S ' METER UG-1094 BNC-F/Panel $1.00 10 for $7.00 ' 9 95 1/e" D shaft, 750 MFD 330V 5/$1.00 3/4" thread section. '` PLS0259 600cc PHOTO FLASH ® 24 -Volt ' CABLE + 4r_,i, COAXIAL 2" HIGH 11/4" x DIA. Rated ' ., POWER SUPPLY l 50 OHM -RG 174 300 Baud, half or full duplex. DAA level \ adjustable 0 to -3, to 6. to TTY $1.25 each -4 - -7 -10. ` and DM outputs brought out to 15 pin Molex __ 5.4 AMPS Edge Meter 250 UA, $4.95/100' $3.00/50' 10 for $11.00 F connectors. SK oscillator sends 1070 Hz space `' fits in 3'e"x 13/4" hole. MFG by and 1270 Hz mark. Receives 2025 Hz space and -- Black background. TEXAS INSTRUMENT MUFFIN FANS 2225 Hz mark Telephone coupler has 4 -ft. core p) )gi ACDC Electronics Inc. KEYBOARD and plug. Size 41/4" W x 15 L x 37 Dp. designed to Model Scale 1-20 Top, be recessed in desk or panel.Electronics in case. OEM 24N5.4-1 10" I x 5" h e 5" w 0-5 Bottom. 6!e W x 12 x 23.7 Op. with B -ft , 3 -wire U -ground $1.95 ea. cord and plug. Operates on 115 vac. 50/60 Hz. Ye Input 105-125 vac 50/60 Hz. Has - ., 1 - -, Amp. Supplied with connection sheet. Removed volt adj and 0.1. adj. Output $45.00 $1.25 ea. 5/$5.00 efetfelflon°ft" 5/$8.00 \ I rum equipment excellent condition, guaran- terminals contain + out, + sen, to *wee ;a: teed - sen, - out, ac newt, ac line and GND.13 LBS. TRIMMER CAP Has 3 slide switches 26 different 3d !\ DB CONNECTORS SAME AS ABOVE EXCEPT keys, key pad removable by 4 screws 25 P 2.50 24 VOLT 7AMP $65.00 1.5-20pF MODEM CABLE 25 S 3.50 T MFG By Rotron Inc. REMOTE 40 CH. C.B. SPECIAL ASSEMBLIES 3 Blades 43/4" Square (AR CO PC -402) ea. COVER FOR DB2 SP/S (PLASTIC) 1.25 NEW HYGAIN 16 MODEL 2716 ( 50e USED $5.50 ea HANDSET HAS DIGITAL CLOCK. 110 VAC $5.95 ea. C &KSWITCHES DIP SOLDER a`., PLASTIC CASE FOR REMOTE IC SOCKETS NEW ' NOT INCLUDED. SOLD AS IS $29.95 Conn 110 VAC Model MU2A1 14 pin 4.14 22 AWG EDGE CONNECTORS 16 pin .16 $12.00 ea. 4,fir ' 18 pin .18 Cond Length 1 " Hood # 20 0 25 P 14 15' pin .24 DIP SWITCH L 3 J-3 25 S 10 Double Row/ Wire Wrap .100 40 pin .40 17'J-60Part # Movement 7' POWER CORD ó..bo% 22 pins$3.4910/$30.00 IC SOCKETS J-60 7101 SPDT 30 pins $3.96 10/$32.00 HEWLETT PACKARD TYPE -= GOLD-PLATED 50 pins $5.4310/545.00 Molded 3 Prong L-3 7108 SPOT WIRE WRAP Plug with molded (momentary) Double Row/ Solder Eyelet .156 POSITION J-3 7201 DPDT (special 6 pins $1.1010/5 9.00 \\\ receptacle g $1.50 ea. 14 pin 40c ea Belden 16 AWG POSITION large rocker) 15 pins $1.6510/$12.50 10 POSITION $2.00 ea. 22 pins $2.08 10/$17.00 16 pin 45c ea $3.00 ea. 12 POSITION $2.50 ea. $1.00 ea. 6/55.00 43 pins $3.66 10/$30.00 TERMS: All material guaranteed unless otherwise stated. 0 you are not satisfied with our product, it may be returned within 10 days for a refund (less shipping). Please add $4.00 for shipping and handling on all orders. COD's accepted for orders totaling $50 or more. All orders shipped UPS unless otherwise specified. Florida residents please add 4% sales tax. Minimum order, $15.00. Foreign orders- US funds only, add 20% for shipping and handling.

CIRCLE 68 ON FREE INFORMATION CARD 119

www.americanradiohistory.com geeee7400 Bulova Quartz Ladies Watches O % Od effe ONE YEAR FACTORY WARRANTY Part No. Function Price SN7400N .20 5N7472N .29 SN71156N .79 70451PI CMOS Precision Timer 14.% SN791N .20 5N7473N .35 SN74157N .69 7015EV/Kit Stopwatch Chip. XTL 24.95 5N7402N .25 SN7474N .35 5N74160N .89 7106CPL 374 Digit A/D (LCD Drive) 16.95 SN7403N .25 SN7475N .49 SN71161N .89 s 7106EV/Kit IC, Circuit Board. Display 34.95 SN7404N .25 SN7476N .S SN74162N .89 7107CPL 3a 01818 A/O (LED Drive) 15.95 SN7405N .29 SN7179N 5.00 5N74163N .89 7107EV/Kite IC, Circuit Board, Display 29.95 SN7406N .35 5N7/80N .50 5N74161N .89 7II6CPL 31/+ Digit A/O LCD DIO. HLD. 18.95 SN7407N .35 SN1482N .99 5N74165N .89 7117CPL 374 Digit A/D LED Dis. HLD. 17.95 5N7408N .29 SN7483N .69 5N74166N 1.25 72011DR Low Battery Volt Indicator 2.25 SN7409N .29 SN745N .89 SN74167N 2.79 72051PG CMOS LED Stopwatch/Timer 12.95 SN71I0N .25 SN7486N .35 5N7/170N 1.95 7205EV/Kit Stopwatch Chip, XTL 19.95 SNIIIIN .3 SN7489N 1.75 SN74172N 1.95 7206CJPE Tone Generator 5.15 SN7412N .35 SN7490N ./9 5N74173N 1.39 MM65Tsö;'á«:lïl,6m mxe5waº;,9;"ñt.us,som e1xó]r"`«,;;°ñilts+nm .2x]3Ts,;':,JïP,mm 7206CEV/Kit Tone Generator Chip, XTL 12.95 SN7413N .40 SN7491N .59 SN74174N .99 7207A IPD Oscillator Controller 6,50 SN1414N .69 SN7492N .45 5N74175N .69 7207AEV/Kit Flea. Counter Chip, XTL 13.95 SN7116N .29 SN7493N .45 5N74176N .79 72081P1 Seven Decade Counter 17.95 SN7417N .29 Your Choice $69.95 ea. any Model 72091PA 5N794N .69 SN74177N .79 - Clock Generator 3.95 SN7420N .3 SN7195N .69 SN71179N 1.9 721SIPO 4 Func. CMOS Stopwatch CKT 13.95 CALL OR SEND ORDER IN REFERENCING TO THIS AD FOR SPECIAL PRICE SN7421N .29 SN7496N ,69 SN7/180N .79 7215EV/Kit 4 Func. Stopwatch Chip. XTL 19.95 Because of Limited a SN7422N .45 SN797N 3.00 SN7/181N 2.25 Supply, please provide second and third choice 7216A1J1 8 -Digit Univ. Counter C.A. 32.00 SN7423N .29 SN74100N 1.9 5N74182N .79 7216CIJ1 -Digit8 Freq. Counter C.A. 26.95 SN7475N .29 SN74104N .89 SN741MN 2.49 LITRONIX Stick Display Sale 721601PI 6.02818 Freq. Counter C.C. 21.95 SN7/26N .29 SN74105N .89 5N7413N 2.49 gag 7217IJI 4 -Digit LEO Up/Down Counter 12.95 W1,1131611 RE F LECTOR RRA FOR C OCRs SN7427N .25 SN74107N .35 SN7/190N 1.25 7218CIJI 8 -Digit Univ. LED Drive 10.95 SN7428N .49 SN74109N .P 5N74191N 1.25 ,r, 7224IPL LCD 444 Digit Up Counter DRI 11.25 .rrrr,.m a FOR SN7/30N .25 SN74116N 1.95 SN74I92N .89 0r °_ .@ r.o , 7226AIJL 1 -Digit Unit. Counter 31.95 , SALE SN7/32N .29 SN7412IN .39 SN74193N .89 ...... o 723AEV/Kite 5 Function Counter Chip, XTL 74.95 SN7437N .25 SN74122N .55 SN7419N .89 .. r. a2a.eE 7251JE CMOS Bin Prog. Timer/Counter 4.95 ,. - , 32034ó SN74311N .40 SN74123N .59 5N74195N .69 A ..,.ri 72421JA CMOS Divide-by -256 RC Timer 805 044 Vim 5N7439N .3 SN7413N SN74196N .89 L 725011E CMOS BCD Prog. Timer/Counter 6.00 .....n1.811,canr ' 1r 21256 SN745N .20 SN74126N .9 5N71197N .89 726011E CMOS BCD Prog. Timer/Counter 6.3 SN7441N .89 SN74132N .75 5N71198N 1.49 2)M 7555IPA CMOS 555 Timer (8 pin) 1.46 SN7442N .59 SN74136N .75 SN74199N 1.49 911.16 75561PO CMOS 556 Timer (N pin) 2.20 SN7443N 1.10 SN7/1/1N .99 SN7422IN 1.25 t/)M 7SIIBCPA CMOS Op Amp Comparator SMV 2.25 ...AI u c..r. 1.11111.1. n u u 1 21 SN7444N 1.10 SN74142N 3.25 SN74251N .99 u 7612BCPA CMOS Op Amp Ext. Cmvr. 51MV 2.95 7621BCPA CMOS Dual Op Amp 3.95 SN7445N .89 SN7419N 3.49 5N74276N 1.95 NATIONAL Display Comp. SMV SN745N .79 SN74144N 3.49 SN74279N .79 Stick Sale 7631CCPE CMOS Trl Op Amp Comp. IOMV 5.35 lap 805000 p AMRAYB 1 M 764ICCPD CMOS Quad Op Amp Comp. IOMV 7.50 SN7447N .69 SN7415N .79 SN74283N 1.49 SN74/8N .79 SN74147N 1.95 5N74284N 3.95 039rt 01.121161 A.» C16.10. 7642CCPD CMOS Quad Op Amp Comp. 10MV 7.50 7660CPA SN750N .20 SN7/15N 1.29 5N7/265N 3.95 MAIM 0y1.,ra 21 M Voltage Converter 2.95 8016CCPD Waveform Generator 1.95 SN745IN .20 SN74150N 1.3 'SN74365N .69 erawi cc eeyNVMI. aR.+gi-o 2a7..s9a8 N1433. NO a+r4w 8 .88.888 1.1111 665CCPE Monolithic Logarithmic Amp 21.60 5N753N .20 SN74151N .69 SN74356N .69 . Ile 1 14.161 88 8 x.1a 8069CCQ Sop pm Band -GAP Volt Ref. Diode 2.50 uali 1 SN7154N .20 SN74152N .69 .69 5N7/367N +.]rae2311 .1. iIReNMe+e f 821ICPA Volt Ref/Indicator 2.95 SN7/59A .25 SN74153N .79 SN74366N .69 1l0 IRNAre4, 8.1.8.11.6 RAMUMe 1mL..m1SRO N º 1118a 8212CPA Volt Ref/Indicator 2.95 SN7460N ,20 SN74154N 1.25 SN74390N 1.49 e.MIAtLplerr LEO NUMERO pMMYa SN7470N .29 SN71155N .79 SN74393N 1.9 +OMo,s, alai 74C00 .39 74C 74C221 1.95 00 w MEN 74CO2 .39 1.59 74C240 2.25 14L50o 74L5192 1.15 OyOr .. VIM1M 74C04 .39 74C107 1.89 74C244 2.25 74LS .7111111 404 74C08 74C373 2.49 74LSo1 : 71L5193 1.15 C..2Nse 74C151 2.% 74L502 .29 71LS92 .75 74LS194 1.15 10.y..s. 911.» 74C10 74C154 3.% 74C374 71L503 74L593 .6 IIL5195 1.15 10P61n ... JO 211.79 74C14 74Cä7 2.3 74C9012.3 74LSM 74LS% .99 11L5197 1.19 10.,AMu. 221M 74C20 .39 74C560 1.69 74C903 aer 71L586 .5 74LS96 1,15 7/LS221 1.19 eeM4ersea cc 404100 46.1 2M 74C30 .39 74C161 1.60 74C911 10-9 1.3611 3 8318 7/LS08 .35 71LS107 .45 74L525 1.49 .. 40.41.0.44.4r Xi 22M 74C42 1.39 740162 1.49 71C912 1096 01 Py 11r1.e 71C915 74L509 .35 74L5109 .45 74LS241 1.49 211.* 74C48 1.95 71C163 1.69 1.69 0 I4L510 .35 74L5112 74L5242 e0 rN,.r.,. 2/a1.19}1.-.1.MOM 74C73 .79 74C164 1.59 74C917 10.95 .5 1.49 is ee e 74LSI1 .33 74L5113 .9 74LS243 1.49 74C74 .79 740173 1.39 14C922 5.9 CA. e 0y 74LSI2 .35 74L511/ .49 74LS241 wrr 2 74C88 71C174 1.39 74C923 5.75 3.9 0009 CC uy1Lr.1. 74LS13 .59 71LS245 74C86 1.99 74C175 1.19 7/C93 7.50 2.95 1.61.121 .3 4E188 CA oenAry 74L514 7171L5112222L5123 74C89 6.95 74C192 74C93 7.50 .99 1..389 74L5247 1.19 14161361. 1.69 74L515 911/á 74C90 1.29 740193 1.69 80C96 .79 .35 71L513 .59 74L525 1.19 , .Or1-110i1.u,s,e 2/166 74L521 74LS15 .59 74L529 1.19 74C93 1.3 74C1% 1.59 80C97 .79 74L521 ^la 201A /Ayr 6394 7/L5132 .99 74L531 .99 oryrurr 26.E6 7aL522 .S 71LSI33 .89 74L5253 .99 110.1...1r1. 92.8 LH0002CN 6.55 LM702H .79 74L53 .35 74LS1ß .49 71L537 .89 e 0y N,r I116 LMIOCLH 4.50 LINEAR LM703CN .89 74LS27 .35 74LSIS .89 74L5258 .69 ..40y4.AYrr 1s1.10+,mo..r.. 1N 2/aas LMIICLH 4.75 LM310Ti 1.3 LM709N .3 7474LS30 74LS139 89 74L530 .69 erNw er Io -.+, 110.1. r,r , LH00700H 4.95 LM310T-12 1.3 .79 .3S 74L5151 .89 74L5266 .69 LM710N TL071CP .79 LM310T-15 1.3 LM711N .79 74L532 .35 74L5153 .89 74L5273 1.95 COMPUTER GRADE CAPACITORS 74L533' ,5946 71L5151 1.75 71L5279 r TL072CP 1.39 LM311P4 3 LM723N .69 .89 MFO WVoC PRICE ur0 WVDC PRICE MFD WVOC PRICE 74L537- 74L51% .99 14L5283 .89 TL011CN 2.9 LM311P-12 .75 LM733N LOO 250 IM 15 74L538 .ß 74L5156 .89 74L5290 190 10,086 2.05 00.000 20 .99 500 22A 2..0 10844 16 LHO032CD 5.80 LM311P-15 .75 LM739N 1.19 7/LS/0 74L5157 .89 744.5293 95 21,110 10 .5 .99 1.250 ] 95 11.000 iS 4.95 33, TL082CP 74LS42 23 95 1.19 LM3I2P-5 .69 LM741CN .3 .89 74L5188 .89 74LS298 1.25 1.500 1.N.; 4,074 5 n 519 00 25 T LONG N 2.19 LM3/2P-12 .69 MC17415CG 3.00 74LS47 .89 71L5160 1.15 74LS352 1.500 0 2.95 11.009 60 5 5 p'10EME 1.29 LH0091CD 74LS48 1.15 7/L5161 1.15 71L5353 1.29 2.074 0 2.95 113.000 6 ri M. ] 95 35.3 LM39P-15 .69 LM747N .79 74L5/9 74L5162 2,250 10 3.95 tW !ri S+.On LM300H .99 LM35N 1.25 .59 1.15 71Lß365 .69 2.300 LM75N 71L551 1.% 74L5163 74LS366 11.000 25 n.OM 5.95 LM301CN 1.15 .69 2.00 41 11.144 10 ].98 9.440 .5 LM350K 5.75 LM1014N 2.75 71LSM 71L5161 74 .3 1.15 LSß7 .69 3,9r U 055 24.144 1 n 55.00 NI LM302H l.% LFSIN .60 LM1310N 1.95 74L555 741..5165 1.15 74L5368 .69 0e ].n 20.000 55 ] 90 13.100 0 90 LM304H 1.95 LFS3N LOO LM158CN .M 74L573 71LS168 1.19 4100 M ] 95 21.000 3 95 96 á 74L5373 1.95 LM305H .99 74L57/ .5 74L5169 1.19 74LS374 LF356N 1.10 LMIS6N 1.3 1.95 40 01 74L575 .59 74L5170 1.95 22:000001 B0,0á0 2 95 LM307CN 5 LFS6N 1.10 LM14MN 1.25 74L5375 .89 i0p 4.95 íJ.00 100.00 1295 74L576 .45 74L5173 .99 71L5386 .69 LM308CN 1.00 LM3MN 1.00 LMI4%N 1.% OVER 200 OTHER VALUES AVAILABLE CALL OR WRITE FOR TOUR 74L578 .49 74L5174 .99 711_5393 cí - REQUIREMENT LM309H 1.% LM59N 1.79 2.19 LMI556V 1.3 74Lß83 .89 74L513 .99 74LS399 2.49 LM309K 1.3 LM37ON 1.9 LM1800N 2.96 74L55 1.3 741_5181 1.95 74L5670 2.49 LOW PROFILE SO LD E R TAIL LM310CN 1.75 LM373N 3.3 LMI871N 5.9 7/LS86 .49 74L5190 1.3 81L595 1.% (TIN) SOCKETS LM3II/CN .90 LM377N 2.95 LM1872N 5.9 71LS90 .69 74L-5191 1.3 81 L597 l.% STANDARD (TIN) LM312H 2.9 LM300N 1.25 LM1877N9 1.24 2599 50.100 3.3 LM317MP 1.15 1.95 74590 .5 745243 3.25 I24 3-09 50.100 LMSIN LM1899N 3.20 74S 8 pin LP .17 .16 .15 LM317T 1.75 LM302N 1.79 1.75 74502 .5 745244 3.25 14 pin ST .27 25 .24 LM1896N 14 pin LP .20 .19 .18 LM3I7K 3% LM384N 1.95 LM2002T 74503 .45 745124 3.95 74531 1.45 16 pin ST .30 27 .25 1.9 16 pin LP .22 .21 .3 LM318CN 1.95 LM386N-3 1.3 74504 .55 745133 -55 745253 1.45 18 pin ST .35 32 .30 LM2877P 2.05 18 pin LP' 29 .3 .27 LM319N 1.% LM57N 1.5 71505 .55 715134 .69 74537 1.35 24 pin ST .49 45 .42 LM376P 2.3 20 pin LP .34 .32 .30 LM331K4 1.3 LM359N 1.5 74508 74515 1.19 745258 1.35 3pin ST .99 90 .81 LM2896P-1 2.8 22 pin LP .37 .36 .ß LM320K-12 LM392N .69 74509 .50 745136 1.75 74530 .79 36 pin 5T 1.39 1.26 1.15 1.5 LM3189N 2.95 24 pin LP .38 .37 .ß LM320K-15 1.35 LF398N 4.00 74510 .45 74513 1.35 745280 2.95 Spin ST 1.59 1.45 1.30 LM3900N .69 28 pin LP .45 .44 .13 LM320T4 LM309H 5.00 74511 .45 745139 1-S 74537 3.25 1.3 LM3905CN 1.3 S pin LP .60 .59 .58 LM321T-12 1.25 TL494CN 1.9 71515 715110 745288 2.75 WIRE WRAP SOCKETS LM393N 1.18 40 pin LP .63 .62 .61 LM321T-15 1.25 TL196CP 1.75 74520 :ú 745151 lss. 7/5373 3 49 LM3918N 3.95 (GOLD) LEVEL #3 LM323K 5.95 NE510A 6.00 74522 .45 745153 1.35 745374 3.49 LM39I5N 3.95 LM324N .99 NE529A 4.95 74530 .5 745157 1.35 715387 2.95 SOLDERTAIL (GOLD) 1-24 25-9 50100 LM3916N 3.95 LM33DZ .65 NE531H 3.96 RC41ßN 1.25 74532 $ 715158 1.35 745471 10.95 STANDARD 8 pin WW .59 .54 .49 LM33IN 395 NE536H 6.00 RCI151NB 7455 1.3 145180 2.95 745472 10,95 10 pin WW .69 .63 .58 3.95 LM331Z 1.30 NESSH 6.00 6.95 74540 .50 745171 1.59 745413 10.% 1-21 319 50-100 14 pin WW .79 .73 RC4194TK .67 LM35Z 1.9 NES44N 4.95 74551 .45 745175 1.59 715474 12.95 8 pin SG .39 .35 .31 16 pin WW .8s .77 .70 RC/l%TK 5.49 LM3S2 1.75 NE550A 1.5 LMISOUA 3.3 74564 50 745188 2.95 745475 12% 14 pin SG .9 .45 .41 U pin WW .99 .90 .81 LM337T 1.95 NE556V .5 ICL8038B 4.95 74565 745191 1.95 745570 5.95 16 pin SG .54 .49 .44 20 pin WW 1.19 1.08 .99 LM337MP 1.15 LM556N .99 LM13060N 1.29 74574 .75 745195 1-% 745571 5.95 18 pin SG .59 .9 22 pin WW 1.49 2.35 1.23 LM338K 6.95 NESMN 3.95 LM13600N 1.9 74586 .79 7451% 1.% 745572 9-% 24 pin SG .79 .3 .69 24 pin WW 1.39 1.26 1.14 LM139N .99 LM566N 1.3 751SN 1.95 745112 .79 745240 L% 745573 9.95 28 pin SG 1.10 1.00 .90 XI pin WW 1.69 1.53 1.38 LM340K4 1.5 LM566CN 1.96 75/50N .89 745113 .79 745211 2.95 745940 3.15 36 pin SG 1.65 1.9 1.26 36 WW 2.19 1.99 pin 1.79 LM340K.12 1.5 LM567V 1.3 75/SICN .39 745111 .79 745242 33 715911 3.15 40 pin SG 1.75 1.59 1.45 40 pin WW 2.29 2.09 1.89 LM340K-15 1.35 NE570N 4.95 75492 .89 CA3010H .99 CA -LINEAR CA30e9N 3.75 CA30I3H 2.15 C A30%N 3.95 CA3060N 3.25 CA3023M 3.25 CA3130H 1.39 1/4 WATT RESISTOR ASSORTMENTS -5% CAPACITOR CORNER CA3035H 2.49 CA308OH 1.3 CA308IN 2.00 CA315H 1.25 10 Ohm 12 Ohm 15 Ohm 18 Ohm 22 Ohm 50 VOLT CERAMIC DISC CAPACITORS CA3039H 1.35 CA3160H CA3m2N 2.00 1_3 ASST. 1 Sea. 27 Ohm 33 Ohm 39 Ohm 47 Ohm 56 Ohm SOppa. value 19 10-99 100+ Value 1-9 CA305N 1.30 $1.95 10-99 1104 CA8088N 1.60 CA3401N .59 !0 Pf .36 .O6 .% Á0114F .96 .O6 .06 'CA3059N 3.25 CA3086N .85 M Ohm 82 Ohm 100 Ohm 120 Ohm 150 Ohm CA3600N 3.50 .1047µF .08 .06 .05 ASST. 2 5e4 180 Ohm 220 Ohm 270 Ohm 330 Ohm 390 Ohm 50pce. $1.95 4722 of .08 .06 .06 O1r4 .00 -06 .OS C134030 39 4098 .08 .06 .% 002µF .09 .07 .06 CD 2.49 470 Ohm 560 Ohm 644 Ohm 820 Ohm IK C0/001 39 C 04506 ZIP; Á174F .09 .07 .06 CD-CMOS ASST. 3 5aa. 12K 1.5K 1.8K 2.2K 2.7K 4770 .08 ,06 .05 .1µF .1) .12 .10 C 04002 39 C 04507 .9º 50pc1 $1.95 Pf CD4g96 1 19 CD4al 1.49 C 04508 3.95 3.3K 3.9K 4.7K 5.6K 6.8K 100 VOLT MYLAR FILM CAPACITORS .001m1 .12 .10 .07 .072mí 13 .11 .06 C04007 25 C04042 .99 C134510 1.39 ASST.4 5ea. 8.2K 10K 12K ISK 18K SOpc1 $1.95 .0022m1 .12 .10 .07 .047mí .21 .17 -13 C04009 9 C134043 CDIS11 1.29 22K 27K 33K SK 47K .0047m/ .12 .10 .07 .Imf .27 .23 .17 C04010 09 C04044 .89 C04512 1.49 ,Olmf .12 -10 -01 .22m/ .33 .27 .22 C04011 39 ASST. 5 Sea. 56K 68K 82K 100K 121K 5opca, $1.95 C 04046 1.79 C04514 3.95 +20% DIPPED TANTALUMS (Solid) CAPACITORS C04012 25 C04047 2.50 C134515 2.95 150K 180K 220K 270K 35K .1/35V .39 .31 .3 1.5/ßV Al .37 .3 C04013 C13403 1.5 C04516 1.49 ASST. 6 5aa. 390K 420K 560K 680K 620K 50pe.. $1.95 .15/35V .39 .34 .29 2.2/35V .51 .5 .34 C 04014 lß C 04599 .19 C D4518 1.79 .29 C01015 1 19 C04050 .69 C04519 .89 IM 1.2M 1.5M 1.8M 2.2M .33.3/ßV .33 .34 4.7/6 V .6 .56 .5 .47/35V .S .34 .29 6.8/25V .79 .69 .56 C 04016 59 C04051 1.19 C04520 1.29 ASST. 7 5m. 2.7M 3.3M 3.9M 4,7M 5.6M SOpes. $1.95 M/36V .39 .34 .29 15/25V 1.S 1.3 .% C01017 1 19 C 04052 1.19 V) C0453 1.79 1.0/35V .38 34 .3 22/6V .79 .69 55 C04018 99 CD1063 1.19 ASST. 8R Includes Resistor Assts. 1-7 (350 pcs.) $10.95 ea. U_ C 00528 1.79 MINI. ALUMINUM ELECTROLYTIC CAPACITORS CD1019 49 C04056 2-% C 04529 1.95 510.00 Minimum U.S. z C04020 1 19 C04059 9.95 C04543 2.79 Order - Funds Only Spec Sheets - 25e Axial 199 100.499 500+ Radial 199 103.199 500+ C 04021 1 39 C 04060 1.19 C 04562 11-% California Residents Add 6% Sales Tax Send 884 Postage for your í7/50V .16 .14 .10 o .47/50V .16 .14 .13 C04022 1 19 C 01066 .79 C04566 2.79 Postage - Add 5% plus $1.50 Insurance FREE 1982 JAMECO cc CATALOG .17 .15 .11 1.0/16V .15 .13 .12 C 04023 29 C 04068 .39 C 04563 2.49 3 Send S.A.S.E. for Monthly Sale Flyer! Prices Subject to Change 4.7/25V .18 .15 .11 1.0/25V50 .16 F C 04024 79 C 04069 .45 C D45B1 .75 .18 .15 .14 C D4005 23 C 04010 U .S C04723 1.95 Mail Or., Eleclonics 10V .16 .12 w C04026 2% C 04071 .49 C04724 1.95 22/25V .19 .16 .12 1.7 /V .16 .14 .13 J C04027 C04072 .49 MC14109 17.95 22/50V .24 W C0403 w C04073 .39 MC11110 .21 .19 .12 18-% 4100/!ßV .16 C D4029 149 C04075 .39 MC14111 15.95 lameco .28 .N 1Ó7/5500V . 5 .1 C 04030 49 C04076 0 1.39 MC14412 15,95 ELECTRONICS 103/50V .41 .37 .34 C D4034 39 C04078 .55 MC14119 7.95 .39 34 126/1óV .21 17 14 o 04035 C 99 C04081 .39 MC14433 1595 2220V . 9 . 5 .41 100/25V .3 .23 .21 `C 01040 1 49 C04082 MC14538 2.49 1355 SHOREWAY ROAD, BELMONT, CA 94002 470/75v ..54 .49 .45 100016 V .21 .19 cc C04093 .99 MC14541 1.95 7O .3 5/82 PHONE .889 ORDERS WELCOME - (415) 592.8097 22110//16V .799 .69 470/25V .3 .31 .27 120

www.americanradiohistory.com UTIC BOOKS MICROPROCESSOR COMPONENTS National Semiconductor - Intersll - Intel SUPPORT DEVICES DATA ACQUISITION (CONTINUED)- MINI STEREO -8080A/8080A 30001 N4tioalCMO6000 Booty 16.% . CPU ADCOSI9CCN well A/O Converter 03-Cn. Multi.) 5.3 1840 74Cerf CDseta eonA/D Converter's Pelt A/D Converter lleCti. Multi.) 10.% FM RECEIVER DM212 aBit Input/OG.7s Aocal,cC5 30002 National Data Book %.% AC103LCN IDBit D/A Conv. Micro. Comp.10.06%I. II.% DP4214 Prlorlly Interrupt Control D mealLi DP,Oa, Dat D53B00, 0676000, alp. WITH HEADPHONES 8.9S DWIº Bl.Olrecllonal Bus Driver DADIONLCN 10-elt D/A Cone MIcro.000e. (e.2ee) 30061 (137ope .riser Data Converter Lm.l SAt Book.%.% OPIM Clock Daneridor/Orlyet OACISOLC5 Melt 0/A 10145 11310 nageai ADC. SAC. LH Swim For Joggers, Cyclists, 5.98 Bus Driver OACepLCN lese D/A'Conwrter (0.205 Ile) 30001 Ndonal TO.ceBD- amrd Level Comoutsr U2lpegnel M.% and Skaters! DPI= System Controller/Bus Driver D AC1282LCN 12-5110/A CPnvetUt (0.2. Lln.) 9.% 30006 Netional Logic Dam Book M.% DPW. System Controller CDI%IN a -Channel Multiplexer 1.11 I6M pages' ]4W,L5,L,X,S, and DM8p00 Swim I/O Expander for Series Av -5.1011 3K BAUD UART 6.96 FEATURES: Lightweight headphones. Left/right INSTN3 4 30006 Buyabove13130001,3,5meet 111.16/lot INeeSo Asynchronous Comm. Element RAM'S balance control. Full fidelity stereo sound. Addi- Interaal Data Book 11071 popes) M.% 12.8251 Prise Comm. I/O (USART) 1.» X809 tional black soft carrying case & shoulder strap. Belt 20101 Static 010100 Intel Component Data Catalog 110.00 0PI153 Proa Interval Timer 0003 05400 % Dynamic Fun data Meets for Inters product incl. memory devfoes, clip (hands free). Operates on 3 AA cell batteries (not p 15S Proº. Peripheral I/O IPPII 3.96 2101 (81011 25.4 Stain microproc., peripherals B indus./mil. product. 11328 pages) x x 1". Wt. OPUS/ Pros. DMA Control 1.75 incl.). Compact size: 3%" 4%" 6 oz. 2102 ION01 Static 205510 Intel Peripheral Design Handbook 17.50 DPIa9 Moe Interrupt Control 21L02 102 x1 Static 195 devin Centro... Full data sheets, epd not.. Intel petiptwrel Model 1810 List Price $89.95 $29.95 OW% Pros. CRT 211118110 21504 Static % components 1644 pages, OW» Prod Keyboard/Display Interface 3182 29644 Static MOs 496 DP9301 m TIInIrIi Element 2114 W24545101 490n1 201 SPEAKERS D WG see el -Directional Receiver 2114E IO.Nxl Static Cons Low Power 2.49 0.307 dell 01-OlrerTlonel Receiver 2114-2 102 x1 Stat lc 20Onr 2.9 AC and DC Wall Transformers DP831 salt 91-Dlreceone Receiver 1114La IRIM stator 23n0 Low Power 2.95 With Unlverasl Plug and OPIUM Octal Latched Prelpheral Driver 75200 29601 Static 6.% 99 gallery Snap O 17630 Octal Lacned Peripheral Or., 4116rv4(UPD416) 1619 Oynamlc50ns(NI h13290/941 l.% voltages: Dynamic icons Selective 8,9,12VDC. SUPPORT DEVICES 415rv.3 6. 14.96 Polarity seleCtIon Six-foot -6800/6800 MM2147N 409601 Fast Tons (4i'). MCM00 MPU line from adapter 10 plugs - six. 5101 25604 State 7.% MC5102CP PU Clock and RAM 14.% rich line (rem adapter to battery MM5261 10201 Dynamic Fully MC6110API psx1 Static RAM 4.% Dcodeo .% snap. 1200160412. 300lnA. 1.01 MMS261 21901 Dynamic _4 I IAMBIAMBipheralPerwn Inter. Adapt 1 S _1-3P_ MS3IO 40%x1 dynamic 4.% Pan No. Input Output Prim MC431 Priority Interrupt Controllerells, 4.% pana 1.25 MM5a0N-tNt114171 HK Dynamic I50m,IO0t M6C531 2.95 AC 250 117VI60H2 12VAC 250nrA $3.95 pane A0201 1.25 .99 SF25016 1.39 MC693U 1024x1-511 ROM (MCMA3da1 1.% MMOIIO.4 A /K Glyn. 2Ma(towerw of MM529011 1.96 AC 600 1170/6002 12VAC 500mA $4.95 204" Round 8'Ohm 21/2" Square 16 Ohm MC6460 AsyncnrOPOW Comm. Adapter s.% - AC1000 117V/80Hz 12VAC 1 amp $5.95 - 125061163 16012K1 Static icons I4.% (4 holes) MC6853 Synchronous UAW Date Adapter a% .25 Watt (4" Leads) .25 Watt mount. Ra Gy 511 RAM (160400) 3.4 AC1700 117V/60Hz 9VAC 1.7 amp $3.95 MCUSO 0631spt Olgltal MODEM IC% Large Ceramic Magnet UPDa1 1 4K Dynamic epin 4.% DC 800 1200/8010 8VDC 400mÁ (bait. charger) S2Á9 Size: 2%" x %" MC6451 MONK Medubtor 2.% TMS IK Stalkatic 9.% 006912 (above) 120V/60Hz 8,9,12VDC 300mA 59.95 Size: 2%" x 2%" x %" MCM3A Ouad}State eu}Tranl(MCSTS) la O 117VI6OH2 53.25 396 1021x4 Static 9.95 09200 9VDC 2000A MICROPROCESSOR CHIPS DC900 t20V/80H2 9VDC500mA $3.95 PROMS/EPROMS 12VDC 53.95 CPU 00111810,11 (2Mez) 11.% DC1200 1200/60Hz 300m1$ 210 ltWCl IERA SK UV Era.. PROM 5% CPU Il% 2 National Semiconductor MA (11011 IMKUM.%..13lo) 2108 aK EPROM CPU 19.% COPLO2 210 EPROM V, 201 9.95 g.% TMSaü (4V, 6 2660 U 27180.11aB)TI 00 EPROM (5 ngle SV7 1.95 CONNECTORS I DM EOIADC -1 . Te Drede) 19.% CPU-Blt Si. (Corn.ma 2772Int1 TI 32% EPROM 1795 13056502 MPU so/Cock(MK Bytes memory/ 11% 210 aK EPROM (45.1) (Single 0501 7.6 _, RAM SALE 001.%N4 (6NNe 2700 GK EPROM (Hitch) HN627611 C.% CPU-Sg1.CllloCPU Belt(IMPytes RAM) 9.% 1553954 5203 M1/PROM lei.% CPU RAM) a.% 15501 N4 (ä6 Bytes 11523174S181) 3201 PROM (Open Collector) 195 STATIC RAMS IN53135 CPU -61 Bytes RAM 0.% 8251115 4096 Blpoler PROM 14.5 eguismem 15 1Nlcro Inter/5 5.96 MM2114N24K (200NSI $2.49 each 53 735 CPU w/Banc 8251231745281) I7.1 Trl-Stm elpolar PROM 3.96 Plneó CPU DB25P D Plug $2.95 (E EACH 518.95/I0t) 100 EA 5195.95/Iot) 825116 sK PROM 16.95 -Subminiature PROMS In Our Catalog MM2114N2L 4Ki2200NSl Low Power . $2.95 each - 0.r 30 More List. - D825S D -Subminiature Socket $3.50 8% ( (E EACH $19.95/1o0 (WO EACH 225.00/100 (117817-1 30 Tune Medal IOU Chip ROM'S D20418-2 Screw Lock Hdwr.121 DB25S/P 2/S.99 MM2147N 4K(7ONS) $4.95 each SHIFT REGISTERS 51312141 character oeneraor (upper Cal. 995 DB51226 Cover for DB25P/S $1.75 (100 EACH $419.957101) 51311820 Cnaradr Osnoaor (Lower cam) 9.95 (8 EACH 534.9511ot) MM5001.1 Dual Wait Dynamlc 22/44SE P.C. Edge (22/44 Pin) $2.95 16K (2200NS) $14.95 each MM33N Dual Men Oynamlc READ ONLY MEMORIES MM6116P4 ...... -NMOS BNC Plug $1.79 (8 EACH $99.95/lot) (1 EACH 51195.00/1ot) M.O. 00.110131 static MCMM710P 15x901 ASCII 51,11154 0/Qr55k 13.50 UG88/U MMSION Dual Galt Accumulator MCM6670P Meal Math Symbol S Pleuras -13.50 UG89/U BNC Jack $3.79 DYNAMIC RAMS MM14217.7 55 -MI Dynamic MCM66750P I2M9 Al Mu. Control Car. Clan. 13.50 UG175/U UHF Adapter $ .49 MM4164N2064K(200NS) $14.95 each MM313N 18215121 Dynamic/Accumulator MICROPROCESSOR MANUALS $0239 UHF Panel Recp $1.29 (E EACH $9095/100 (100 EACH $1195.001101) MMMMN 500/612.0111it-a °yarn. M-282 Me, Manua 700 Adapter $1.60 M M5290N2 16K 5ONS) 4116 $2.95 each 10.03.1 Octal den M-CDP1882 um. seenW1 7.90 PL258 UHF (E EACH 519.951101) (100EACH $225.00/1011 543350 Octal eBn m.2660 pier Manuel PL259 UHF Plug $1.60 IOlaall Dynamlc MM5290N-4 16K 50NS) 4116 $1.95 each 250v14GA) SPECIL UNCTION 5 20 UG260/U BNC Plug $1.79 5117 Hex 0a811 Static (E EACH 514 951101) (100each 175.101101) 0500505 Dual MOS Cloc6 Dryer 551112) 3.3 UG1094/U BNC Bulkhead Recp. $1.29 2592V Owe 132 -ait Static 053505 DWI MOS Clock Orlvel (5MZ1 Zee Bean ['yearnsris INSI77IN-1 Floppy DISK Controller aav 1025.811 Dynamic INS166IN cetIOn Chip 19.% TRS-80 EPROM Erasing Lamp á21V Dual Beall seam MSMI67N RealMI %me Clock e.% 555V Duel Meg 55atm MM521GN Mr Clock Il.R 16K Conversion Kit 55 0 D ual »Malt 5%110 001.25 Mlcroconloller with G-01º11 RAM 6.% Expand your 4K TRS-80 System to 16K BUN Quad pelt Static and Octet' LED D'I^ Kit comes complete with: 3311PC Fllo (0.110) COMM. t 640NIt RAM 7.» DATA ACQUISITION Dlract LED Orls0Ow/N lids Mt. 8 ea. MM5290 (UPD4/6/4116) 16K Dyn. Ram (na) AF10bICN U 0í Filter 15% COWAN 3156a6.0Á0 Fluor. Dever (Mein ww.) 15 Documentation for conversion ÁF121.101 Tonens Low Band Filter TELEPHONE/KEYBOARD CHIPS 2716, 1702A, 52030, 52040, etc. /kneelC1 Touch Ton Bane Filter TRS-16K2 150ns 19.95 Erases 2708, A0441M Push Button Tetpnon Dialer 14.% Oeln OP0, Amp 16.95 Erases up to 4 chips within 20 minutes. LM3MCH Super -1005 TRS-16K3 200ns AV+5433 ceno.y Dialer Constant Currant Source exposure distance of one inch. U.S. gV44x0 CMOS Clock Generator TRS-16K4 250ns - 14.95 Maintains constant 19M1166 Temperature Transducer VS576 .000.14 Encolo Be keys) 11.% Special conductive foam liner eliminates static build-up. JFET Input OP Amp LF356N 1005144 ICeyeoard Encoder 18 keys) LF39114 Semple a Hole Amallt.ers Built -In safety lock to prevent UV exposure. 7.922 Keyboard Encoder key0 5.09 LM39.1 Tern Comp, Prec. Ref. (900m/ó 196 Compact - only 7-5/8" a 2-718" x 2" 740123 Keyboard Encoder (20 keys) 5.21 C nraner LL5191S A003101LCN I-SII A/O Push Bettors Put., Dialer Complete with holding tray for 4 chips. DACOMIC 4911 0/40 Consenter M Lind 01057143N Keyboard 8.95 UVS-11EL Replacement Bulb $16.95 96//140Key Serlal Encoder EECO Rocker DIP Switch - "MInI-DIpTM" 2400 Series UVS-11E $79.95 THE MOST UNIQUE D P SWITCH AVAILABLE! MINI -DIP Is designed to relrofl all major brands of Dip SM1018, Unique Iealures include locking Datanectics 74 -Key Keyboard i rod design to prevent acciattic]tal actuation and gold sell'wlpng eon1001. One-piece koutIng and Uses EA 20134 Chip (Electronic Arrays). Size. 167/"L k 5%.'W k press -Ill terminals prevent ntaminatlen. 2.10 station Form "4" and 1.5 0121101 Form 1.3/8"5 While, black, blue, grey key cape. (No Data Sheet) - JOYSTICKS Tureen .100 x molars or e nlpsabY Psalm 2400.10 cleaning/wiping action en l I2.54oM mead TOW seal and teal Part No. KB354 $29.95 ea. Pan No. Pas. Conligurnlel Socket Prim lin Mo. lis. ConOgurdion Stoke Prim 2400-2 2 12 8 pin .79 - 10/ 0.05 2400-6 6 123456 /4 pin 1.09 . 10/ 095 1100-3 3 123 8 pin 89 - 10/ 7.95 2000.7 7 1234567 14 pin 1.19 - 10/10.95 i 24001 4 1231 8 pin 99 - 10/ 9.95 2400-8 5 11345578 18 pM 1.29 - 10/11.95 "asi43>r:} 2400-6800 4 6000 8 pin 99 10/ 8.95 24009 9 123456789 18 pin 1.39 - 10/12.95 2400-5C 5 054321 14 Pin 1.09 - 10/ 9.95 240010 10 0123458789 20 pin 1.49 10/13.95 Micro Switch 69 -Key Keyboard Uses AMI SW2035014 Chip. Size: 163/ß"L x 5`40"W x 1518"H Metei Frame. Light 5 dark gray key ceps (NO Date Sheet) J VC -00 GRAB BAG Part No. KB69SD12-2 $19.95 ea. JS -5K 5K Linear Taper Pots $5.25 Above) JS -100K 100K Linear Taper Pots $4.95 GB180 (Pictured Boschert Multi -Voltage Power Supply SPECIALS 5VDC, 12VDC and 24VDC JVCd0 40K (2) Video Controller in case $4,95 CAPACITORS RESISTORS 111,1. 112.00 8814 2o0ä7N nun norm. -sl.wl 82 MUFFIN® FAN 0000, 013.ssneasss 480 011111 21:1011.0 1/2 wan miner Mpg dependable low 00eí, lergssl e.0lsR lot tan commercial cooling sppllmtlone INTEGRATED CIRCUITS 10501m free air delivery O 0100 401 SWITCHES FEATURES: Voltages.: 5VDC 60 25amps,12VDC fry 4ampe a 24VDC 4amps. Reg. Losd: 450 out 1%, 12 5 24V out 5% (26100% 4.68' sq. x 1.50" depth. Weight - 17 oz. 30ear.Lna.-rmrlu2 4.00 protection. 116 or 230VAC Input. Wt. 1 lbs. acoustical rating as low as No-38 load). Overvoll a overcurt. .003 Size: 4.95" t 2.50" x 15.00" cont.ed dory at 10c O 0,4111 cali 'N°ei `','',",r average output shall not exceed 200 watts. Impede 210100c 'Total t MOO General Descnp

Dual Power Supply 600 JE600

General Description: The JE215 is a Dual Power POTENTIOMETERS - Hexadecimal 0000 Supply with independent adjustable positive and nega- 3 00 Encoder Kit tive output voltages. A separate adjustment lar each 0111.26 000 FULL 8 -BIT of the supplies provides the user unlimited applications 0.1128 3.00 LATCHED OUTPUT for IC current voltage requirements. The supply can 19-KEY KEYBOARD 7...y-Ine,..1 Mar 300 as a also be used general all-purpose variable power DIODES e,"hm,rv,e supply. FEATURES: 0.111 The JE600 Encoder Keyboard Kit provides two se hexadecimal digit. produced from sequential key entriee Adjustable regulated power supplies, 011101 to allow direct programming for 8 -bit microprocessor Poe and neg. 1.2VDC to 15VOC. keys pro- Power Output (each supply): or 8 -bit memory circuit.. Three additional are vided for uaer operations with one having a bisteble 6V DC @ 500mA, 10V DC CO 750mA, 25c $10.00 Minimum Orde, - U.S. Funds Only Spec Sheets - output avalleble The outputs era latched and monitored 12VDC@500mA, and Resldenla Add 6% Sales Tax Send 886 Postage for your 16VDC@ 175mA. California with 9 LED readouts. Also Included Is key entry strobe. Add 5% plus $1.50 Insurance FREE 1982 JAMECO CATALOG 8 latched output for mlproprocassor Two, 3 -terminal odl. IC regulators Postage - Features: Full -bit Flyer! Prices Subject to Change use. Three user-defIns keys with one being bletable tp with thermal overload protection. Send S.A.S.E. for Monthly Sale Heat sink regulator cooling Operation. Debounce circuit provided for ell 19 keys. Mail Order Electronics - W ondwide 9 LED readouts to verify entries. Easy interfacing with LEO "on" Indicator 45VDC Printed Board Construction standard 16-pin IC connector. Only required 120VAC Input for operation. Size : 39"1-10 86"W x 899"0 Size: 3-1/2"w x 5.1/16"L x 2"H $99.95 ameco JE600/DTE-HK asvf Ctuiáá áóglg) .... JE215 Adj. Dual Power Supply Kit (as shown).. $24.95 ELECTRONICS JE600 Kit Lirkie rái,cralárñilnóëá >.-$59.95 ( FMB/ re not shown but elm liar in construction to above) JE200 Reg. Power Supply Kit 15VDC, 1 amp) .. $14.95 94002 K19 I9 -Key Keyboard (Keyboard only).... $14.95 JE205 Adapter Brd. Ito JE200) 05,0921 s12V. $12.95 1355 SHOREWAY ROAD, BELMONT, CA DTE-HK (case only -373"Hxe1/4"Wx83/4"0) $44.95/ JE210 Var. Pwr. Sply. Kit, 5-15VDC,to1.5emp. $19.95 5/82 PHONE ORDERS WELCOME - (415) 592.8097 CIRCLE 63 ON FREE INFORMATION CARD

www.americanradiohistory.com ELECTRONIC KITS FROM HAL-TRONIX QUALITY at parts 2304 MHZ DOWN CONVERTERS. TUNES IN ON DISCOUNT PRICES! CHANNELS 2 TO 7 ON YOUR OWN HOME T.V. AMAZING HAS FREQUENCY RANGE FROM 2000 MHZ TO 4 CHANNEL 8 TRACK 2500 MHZ. EASY TO CONSTRUCT AND COMES 1. HOME UNIT COMPLETE WITH ALL PARTS INCLUDING A ALUM CASE AND COAX FITTINGS, (-de, BRAND NEW UNITS... DIE-CAST ASSEMBLY INCLUDES; REQUIRE A VARIABLE POWER SUPPLY AND a dish type TAPE HEAD, MOTOR BEL , DEVICE ANTENNA (Antenna can be 411! 110VAC on the `r01,, MOTOR, PRE -AMI', PHASORSISHOCKWAVE or coffee can type depending ..,á ,il LIGHTS, SWITCHES, PPF-1. PHASOR PAIN FIELD - Is being tested by Gov't for riot control. Soon signal strength in your area.) SOLENOID AND OTHER to come under weapons restnctlons as an Infernal machine. Easily hand-held Hazardous- Use with discretion SOLD ONLY FOR ANIMAL CONTROL. Kit) $49.95 USEFUL PARTS.... 2304 MOD 1 (Basic PPF-1. PLANS... 815.00 a fittings) AN EXCEPTIONAL BUY! (LAM CAM IPG-3 INVISIBLE PAIN FIELD GENERATOR - Produces dlrectionat held 2 (Basic / Pre -amp) $59.95 57.25 PER ASSEMBLY of moderately intense pain to lower back of head up to 50 It. Clgaretle pack sized 2304 MOD Preludes caw a 11111ng01 enclosure Is easily hidden. PLANS KIT 3 -Gain Pre -amp) $69.95 BLACK 1Pß3 $7.00 1P41 -3K 839.50 2304 MOD (Hi PLASTIC . 4PDT RELAY IP3-30 . ASSEMBLED FOR ANIMAL CONTROL. 849.50 (Include. CAM 4 mango I. pi style HUG -1. HIGH POWERED ULTRASONIC GUN - Produces directional 130 POWER SUPPLY FOR EITHER MODEL ABOVE IS 3 amp contacts CASE dbs of sound energy at 20.24 kHz. Hand-held. intended for lab use. ALL PARTS, 24yotdc or pressure AVAILABLE. COMES COMPLETE WITH r*z PAC -TEC HUO.1 PLANS .. 510.00 120 yoilc -° ... .. CASE, TRANSFORMER, ANTENNA SWITCH AND Used but fully lasted QWI Ì0 SERIES C LASERS CONNECTORS (Kit) $24.95 EACH PARTICLE BEAM WEAPON . PLANS 815.00 $34.95 $1.70 BEGINNER VISIBLE RED NON -HAZARDOUS OPTICAL Assembled specify coil voltage LHP-2. Slotted Microwave Antenna For Above LARGE QUANTITIES AVAILABLE DEVICE. Adjustable pulse BLACK PLASTIC ENCLOSURE PLANS KIT. Downverters $39.95 PFI AY Sop each LHP2 $7.00 LHP-2K $39.50 ADJUSTABLE HEIGHT FROM LP-3/LRG-3 LASER PISTOL AND RIFLE COMBINATION - 7-24 watts MINI SIZE 1.63" TO 2.93"; WIDTH of infrared energy. PREAMPLIFIERS 6.85"; DEPTH 8". BUILT- LP-3ILRG-3 .. PLANS .. $10.00 HAL PA -19-1.5 mhz to 150 mhz. 19db gain operates BUZZERS IN STAND OFFS FOR P.C. LGU-1. VISIBLE RED LASER GUN for holography, special effects. cloud on 8 to 18 volts at 10ma. Complete unit $8.95. 3 volta th to 7548- BOARDS -FRONT AND BACK writing. etc. HAL PA -1.4-3 mhz to 1.4 ghz. 10 to 12 db gain oper- fl LEADS LGU-1 ... PLANS . 810.00 H WIRE PANELS NOT INCLUDED.. ates on 8 to 18 volts at lOma. Complete unit $12.95. LC -1. BURNING/CUTTING CO2 LASER 10-40 watts continuous. $5.25 PER CASE - (The above units are ideal for receivers, counters, etc.) 15.4.-oh t WTvolts3 75tea LC -1 . PLANS ...... 515.00 .0 WITH PIN TERMINALS JOYSTICK RUB -1. WELDING/DRILLING RUBY/YAG LASER, Intense red. RUB -1 PLANS . .. $15.00 16 LINE TOUCH TONE DECODER KITIitl PRECISION 3 to 7 volts 1195-t HIGH POWERED PORTABLE ENERGY SOURCE FOR P,C. BOARD AND PARTS $6w9.95 ITH PIN TERMINALS DEVICE... LASERS & MAGNETIC WEAPONS exploding wires. shock waves. etc HPS-1. PLANS $8.00 HPS1K.... KIT $49.50 KIT WITH --el 75ceach CONTAINS 4 LINE TOUCH TONE DECODER 50K CENTER SECURITYIPERSONAL PROTECTION e. C. BOARD AND PARTS $39.95 TAPPED ALPS tNF-1. INFINITY TRANSMITTER - Uses telephone lines for selecllve home MITSUMI POTS or office listening while away on busIness or vacation 16 LINE ENCODER KIT, COMPLETE wiT MODEL UES-A55F INF-1 PLANS . ... $15.00 PAD AND COMPONENTS $59,95 VARACTOR UHF TUNER $ 4.75 each 50.4. SEE IN THE DARK - Device, long range SD -4... PLANS. $10.00 CASE, VWPM-5 WIRELESS TELEPHONE TRANSMITTER Long range FRED RANGE - ENCODER KIT, COMPLETE WIT FLAT LEVER VWPM-5 PLANS $10.00 VWPM-5K KIT $34.50 12 LINE 470 - 889 MHZ CASE, PAD AND COMPONENTS ....$29.95 ANA MINI -TOGGLE FBT-7. WIRELESS MICROPHONE - Extended range. ANTENNA INPUT S.P.DT (ON -ON) PET -7.. . PLANS $7.00 FBT7K KIT, $34.50 300 OMAS 5 M1P 'i 120 VAC HOD-1/TT-6 ELECTRONIC TRACKING AND HOMING DEVICE - C & K 7101 KIT MANY, MANY OTHER KITS AVAILABLE $25.00 each HOD-NNTT-8 ... PLANS ... $8.00 HOD-1K/TT8K $39.50 $1.00 EACH TAT -2 ANDND TELL Device records telephone when In use. 10 for - S se Newman i S 8.50 TAT -2.. PLANS. $5.00 TAT-2K ...... $14.50 iw:»máxNALiñóaizwá phone 10 for $220.00 100 for $75.00 PSW-3. PHASOR STUN WAND - Produces energy capable of burning flesh. a Intended as a last resort personnel defense weapon. p SEND FOR NEW 1982 PSW-3 PLANS $8.00 PSW-3K KIT $59.50 HAL-TRONIX ree: 40 PAGE CATALOG fries Send for tree catalog descriptions of above items. kits and pans. plus hundreds P.O. Box 1101 more. We accept. Master Charge and VISA or when ordering send check or money Southgate. MI 48195 COMPUTER order to, w.:,N L.E. D.'s SCIENTIFIC SYSTEMS OROERS OVER 535.00 WILL BE SHIPPED POSTPAID EXCEPT CHARGES GRADE DEPT. 88 BOX 716, AMHERST N.H. 03031 SNIPPING ITEMS STANDARD JUMBO OONN ORDERS ILLESS THAN 5AS.00L PLEASE INCLUDE ADDITION.T CAPACITOR DIFFUSED INFORMATION, AL 12.00 FOR HANDLING AND MAILIND CHARGES. 1700 VDC CIRCLE 87 ON FREE INFORMATION CARD CIRCLE 91 ON FREE INFORMATION mfd.150 $2.0 RED FOR $1.50 CARD 2 1/2" DIA X 4 3/4" HIGH i 3,600mfd. GREEN 10 FOR $2.00 1 40VDC _UK':'8" YELLOW 10 FOR $2.00 30 TUNE DIA. X 3" HI FLASHER tepecy 6,400 mfd. LED P'M 5 VOLT OPERATION MELODY 44 60VDC $2.50 JUMBO SIZE. 1 38 `Dlw X 4 I/4' 2 FOR $1.70 12,000mfd. 40 VDC $3.00 MICROPROCESSOR 2" DIA X 4 1/4" HIGH BI POLAR L E D 18,000 mfd. 75 VDC $4.00 2 FOR $1.70 FEATURES APPLICATIONS 2 1/2" DIA X 4 1/2" HIGH SUB MINI LED 30 Melodies Eleclronlc Doorchlmes 20,000 mfd. 25VDC ------4N------Variable Tune Speed Musical Car -horn FREE " DIA. X 21" HIGH $2.00 Variable Volume Entrance Warning VDC .079" .0980 Direct Output To Speaker Music Box 22,000 mfd.15 20mA at 1,75v Auto or Manual Tune Change etc... ,,A X Z II2`,.Ic., $2.00 10 FOR $1.00 Low Power Spec Sheet & Typical Circuit CATALOG 22,000 mfd.4OVDC 200 FOR $18.00 Operated By Two 9V Batterlea Schematic Included X HIGH ."' DIA. 6" $3.00 QUANTITY PRICES AVAILAGL, 5.000 mfd.75 VDC $4.50 Pomp A ckE.nrlanom 11 L...arMllat 2l vin... XLRA-3-13 Auld Lang eye. ,2 Happy &mwy a Wedding Maly 3" DIA X 4 3/8" HIGH ANNON BurglarlFire Alarms 45.000mfd. Uses aN1. a Salk« Hpmwe 25 VDC CONNECTOR Rur ar..MnY 1. ardrn cnau IF.u.O M Maw and Namwe LIA. X 4" HIGH $350 3 PRONG Watmn..- GTURae IB Gem E,raun.Ms Th.nt ä correogy Much Security Products 72,000 mfd. 15 VDC CRASS I5 MOUNT a.aMArrMw ISO C.n.d.' as T-,w,ld T Win.» un. NM 71 A. x 4" HIGH $3.50 CONNECTOR elwnelwwe It »mean u., Dance at Willem Tan Own« $2.00 EACH Star Se.new d eonsW 1/ God saw The Ouen a Eye of Team CLAMPS To FIT CAPACITORS SO. es. 10 for $19.00 Mozart anela le dare.. a Wirt 21 Bach Tprc.t In D alma SUPER SMALL Beemo M' Son 9ymp on. 70 ghee Dem. W.0 xl W.I. BLACK LIGHT PHOTO -FLASH (ULTRAVIOLET) Two For $13.00 170 MFD 3301f Special Offer $6.95 I'" X i 7/8" G.E. I F6T5BL $2.50 each Ca. Res. Add 6°/e Tax Postage & Handling Add 2 FOR $1.50 10 FOR $7.00 TRANSFORMER LIMITED QUANTITY 750 MFD 330 V aälk 120 volt CLEARANCE PHOTO FLASH ,m°,,w,, '115H X 1 1/4" DIA. ,,,L ;. primaries Electronic Door -Tunes $1.25 EACH -.- FOR $11.00 .:24-..29 10 6 VOLTS at 150 mA 51.25 These units are Alarm Controls Remote Stations 500K LINEAR 12 V. C.T. at 500 mA $2.50 complete with all 16.5 V. at 3 AMPS $6.50 Infrared Motion Detectors Sirens SLIDE POT 18 VOLTS at 350 MA $2.00 parts including 2 7/8" LENGTH Microwave CCTV Fire Detectors 18 VOLTS at 1 AMP $4.50 microprocessor 1 3/4" TRAVEL 25.2 AMP 3V VCT at 2.8 $5.50 Vehicle Alarms Phone Dialers 75S EACH described above. Minor problems Key Locks Wireless Components 2" ALLIGATOR CLIPS MRF 901 70lipp for 12.00 5P E.1F require trouble- Magnetic Contacts Glass Protection G.- TRANSISTOR 100 clips for 512.00 shooting. Lights System Parts Tools Books ' ° $2.50 clips for $50.00 EA. Bells Ionization Smoke Detectors ALL ELECTROAICS CORP. Schematic included, as is... only $14.95 & Handling... S 3.00 905 S. Vermont Ave. TERMS Shipping P O. BOX 20406 OuanHries Llm,ted 500K Lin. Pots: 65'ea. or 4/$2.00 west Los Angeles, Min. Order 1,000 Ornountain Calif. 90006 Add $2.50 6Ft. Coax with RCA plugs: 3/82.00 (213) 380-8000 snlppIng OSA Ca. Res. Add 6% Tax Postage 50" 4215 N. 16th Street Dept. RE -5 ColII. Res. Add 6"i" Check or M.O. Visa & Master Card Accepted Mon. Fri. Saturday Prompt Shipping Phoenix, AZ 85016 9AM5PM 10 AM-3PM SRJ INTERNATIONAL CORP. ISO 1936 Hillman Avenue 1-800-528-6169 Belmont, Calif. 94002 J CIRCLE 75 ON FREE INFORMATION CARD CIRCLE 89 ON FREE INFORMATION CARD CIRCLE 86 ON FREE INFORMATION CARD

www.americanradiohistory.com PAT./14,259,705 ES HOBBYISTS & EDUCATORS WARNING! FREE! 1982 Electric Power Pollution, DISCOUNT Spikes, ELECTRONICS Interference CATALOG & Lightning HAZARDOUS to& ISO -3 JOIN THE PAK! HIGH TECH EQUIPMENT!! Send for our Free catalog and become a ELECTRONICS CO., INC MicroComputers, VTR, Hi-Fi, Lasers, member Spectrometers are often damaged or dis- of our exclusive Pak. Our SEND OR CALL rupted due to Power Pollution. members receive Poly Pak s' for your FREE 1982 High Tech components may interact! exciting catalog several PPG Electronics Projects Our patented ISOLATORS eliminate times a year. We of fer: A equipment interaction, curb damaging Penny Sales. Free 48 page Handbook/ Power Line Spikes, Tame Lightning bursts Handbook with \ catalog. & clean up interference. Premiums and Low, 48 SUPER exciting, Isolated 3 -prong sockets; integral Spike/ Low Prices on a wide variety of Lightning Suppressor. 125 V, 15 A, 1875 W low cost, electronic Electronic Products such as Computer Periph- Total, 1 KW per socket. projects. (Some projects erals. Integrated Circuits, Speakers. Audio as low as $2.50). ISO-1 ISOLATOR. 3 Isolated Sockets; Quality Spike Suppression; Basic Equipment. Rechargeable Batteries, Solar Prod- EACH PROJECT Protection $69.95 ucts, Semiconductors, and much, much more! is shown with: ISO-3 -ISOLATOR. 3 DUAL Iso- - Complete schematic SUPER Take advantage of our 25 years as America's Suppressor; Com- Complete parts list lated Sockets; RECEIVE - mercial Protection $104.95 foremost Supplier of discount electronics. Project description full information - RUSH] Kit prices ISO-17MAGNUM ISOLATOR. 4 QUAD ME YOUR FREEDISCOUNTCATALOG! on projects Isolated Skts; Suppressor; Labora- NAME - such as: tory Grade Protection .. - . $181.95 MasterCharge, Visa, American Express ADDRESS TOLL FREE ORDER DESK 1-800-225-4876 CITY- (except AK, HI, MA, PR & Canada) DUAL BURGLAR ALARM STATE: ZIP SATISFACTION GUARANTEED! TELEPHONE HOLD BUTTON CLIP AND MAIL COUPON TODAY TO: Electronic Specialists, Inc. POLY PAKS, INC. P.O. 171 South Main Street. Natick, MA 01760 Box 942RA-5 S. LYP4NFIELD, MA. 01940 (617) 245- 3828 Technical & Non -800 1.617.655.1532 CIRCLE 90 ON FREE INFORMATION CARD CIRCLE 88 ON FREE INFORMATION CARD STROBE LIGHT NERVE TESTER

P. 0. Box 280298 Dallas, Texas 75228 B. G. MICRO (214) 271-5546 Visa MasterCard American Express

STATIC RAM SOCKETS 74LS

-21 L02-1KX1 250 n.s. LS00 .24 LS125 95 L5243 1.49 Low Power 95 Low Profile LSO2 .24 LS138 .79 LS244 .99 2114L-3 1KX4 300 n.s. Solder Tail LSO4 .24 LS139 .79 LS245 1.95 Low Power .... 2.75 8/17.95 LS05 .24 L5151 .79 LS257 .79 14 Pin 10/1.00 ROBOT -1M6116P4-2KX8 + 5v-200 n.s. LSO8 .24 LS153 .79 LS266 .59 BLINKER 3 -CHARNEL COLOR ORGAN CMOS Low Power 2716 16 Pin LS10 .24 LS154 1.75 LS283 .99 Style Pin Out 13.50 8/1.00 LS14 .89 LS157 .79 LS290 .99 8/95.00 18 Pin 8/1.00 LS20 .24 LS161 .99 LS293 1.75 TMM20/6-2KX8 + 5v-NMOS LS27 .24 LS164 .99 LS298 .89 200 n.s. - 2716 Style Pin 20 Pin 7/1.00 Out 13.50 8/95.00 LS30 .24 LS166 .99 LS367 .79 LS32 .36 L5175 .89 LS368 .79 DIGITAL SLOT MACHINE COMBINATION LOCK MK4104J-4 25ONS 24 Pin 6/1.00 4K 1 LS42 .49 LS181 1.99 LS373 .99 x STATIC 18 PIN CERAMIC Also available, Computer Mfg. Surplus. PRIME. Fully 40 Pin 5/1.0D LS74 .44 LS192 .89 LS374 1.49 complete Static. Easy to Use. Has Same Pin Out LS85 .95 LS193 .89 L5375 1.19 Basic Electronics Course as TMS4044, but slightly different LS86 .39 LS221 1.10 LS377 1.49 timing. With Specs. (Mostek) Buy $10 Get $1.00, LS90 .69 LS240 .99 L5390 1.19 DEALERS 8 for 12.00 Cash in on the electronics revolution now 32 for 39.95 FREE CHOICE LS109 .39 LS241 .99 LS393 1.19 VERY LOW POWER' PPG has sold hundreds of thousands of these LS123 .99 CS242 1 49 LS399 99 Q' electronic kits to. schools and training DYNAMIC RAM MISCELLANEOUS EPROM institutions. We are offering these excitlli: kits through electronics TR1602-UART same as -Aslerk Denotes Super Specials stores across thr 2107B-4 (MM5280N-5) nä11011 AY5-1013 199 '1702A 256X8 1 us .. 2.50 4KX1 22 Pin 1.59 IM6402-+5v High speed 2708 1KX8 450 n.s. 2.95 Contact us immediately for your Dealer's UART-AY5-1013 27A08 1 KXB 350 n.s. 3.95 Free Information Package. 4027-4KX1-250 n.s 1.75 pin out 2..00 '2716 2KX8+5v 450 n.s 5.95 Find out how you MC1488-1489-R5232 Receiver 2716-1 2KX8+5v 350 n.s...... 9.95 can get started in this exciting '4116-16KX1-300 n.s. ... 8/12.95 and fast and drive H.# 1-19 '2732 4K08 450 n.s. growing retail market. -4116-16KX1-200 n.s. .... 8/15.95 AY3-8910-Sound Chip with 60 Intel Pin Out .... 9.95 page data manual 12.95 2532 4KX8 450 n.s. CALL THIS TOLL -FREE HM4164- +5v 64K Dynamic 82S123 -32X8 Tri State Bi polar T.I. Pin Out 9.95 o NUMBER FOR YOUR FREE 12.95 8/95.00 PROM 3.99 2732A-3 4K a 8 350 n.s. HANDBOOK AND THE NAME 4.916MHZ Baud Rate Intel Pin Out Low Power 12.95 OF THE DEALER NEAREST YOU. Crystal 1.99 VOLTAGE REGULATOR 1771 Single bensity Floppy Z80 Toll -Free 1 (800) 453-1708 7905 .99 7805 ü9 Disc Controller 22.50 Z80A-4MHZ CPU 8.95 7912 .99 7812 .99 1791 Double Density FDC 29.95 Z80P10 - Parallel 5.95 7915 .99 7815 .99 DM8131 6 Bit Unified Bus 2B0SI0/0 Chan. Ser. 24.95 Utah residents 1 (8011 628-3627 7924 .99 7824 .99 Comparator 2.99 Z80A 510/0 29.95 LM317T - To 220 1.75 8 Pin Dip Jumpers 3/1.00 Z80DMA-13MA PPG Electronics Co., Inc. 'LM323K-5v-3A. To -3 3.95 3/10.00 825129 Tri State Bi Polar Controller 9.95 791 Red Rock Road, 1 -A5'1412-12v -3A To -3 3.95 3/10.00 Prom SPECIAL 2.59 280 2.5 MHZ CPU 6.99 m St. George, Utah, 84770 CALL OR WRITE FOR PRICES ON CMOS-8080 - BIT SLICE - TTL - 74S TERMS: Add 51.50 postage, we pay balance. Ord rs over 550.00 add 850 for insurance. No C.O.O. Texas Res. add 5% Tao. 90 Day Money Back Guarantee on Special Prices For all items. All items subject to prior sale. Prices s bject to change without notice. Foreign order ''U.S. funds only. We cannot ship to Mexico. Countries other Educators than Canada, add $3.50 shipping and handling. CIRCLE 81 ON FREE INFORMATION CARD

www.americanradiohistory.com LOW TIM DC STEREO PROFESSIONAL REGULATED VARIABLE PRE -AMP KIT TA -10 20 NEW MARK III D.C. 9 Steps 4 Colors POWER SUPPLY KIT Incorporates brand-new D.C. design that gives a frequency All solid state LED circuitry with high efficiency power transistor response from 0Hz-100KHz ± 0.5dB! Added features VU 2SD388 and I.C. voltage regulator MC1733. Output Stereo level indicator kit with arc -shape display panel!!! like tone defeat and loudness control let you tailor your voltage can be adjusted from 0.30V at 1 amp current This Mark III LED level indicator is a new design PC board own frequency supplies to eliminate power fluctuation! limited or 0-15V at 2 amp current limited. Internal with an arc -shape 4 colors LED display (change colorfrom Specifications: T.H.D. less than .005% T.I.M. less resistance is less than 0.005 ohm; ripple and noise less red, yellow, green and the peak output indicated by rose). than .005% Frequency response: DC to 100KHz ± than 1 MV, dual on panel meter for voltage and amp The power range is very large from -30dB to +5dB. The 0.5dB RIM deviation: ± 0.2dB S/N ratio: better reading, also with on board LED and audible over load Mark Ill indicator is applicable to 1 watt - 200 watts than 70dB Sensitivity: Phono 2MV 47K/Aux. 100MV indicator. Kit comes with predrilled P.C. board, instructions, amplifier operating voltage is 3V -9V DC at max 400 MA. 100K Output level: 1.3V Max output: 15V Tone all necessary electronic components, transformer and a The circuit uses 10 LEDs per channel. It is very easy to control: bass ± 10dB @ 50Hz/treble ± 10dB @ 15Hz professional look metal cabinet. The best project for connect to the amplifier. Just hook up with the speaker Power supply: ± 24 D.C. @ 0.5A school and the most useful Instrument for repairman. output! Kit comes with regulated power supply all you need is a Build one today! (1. r'A IN KIT FORM 48V C.T. transformer @ $18.50 MODEL TR 88A 0 ~15V D.C. 2 amp MODEL TR 88B 0^30V D.C. 1 amp ONLY $44.50 MARK IV 15 STEPS LED X'former POWER LEVEL INDICATOR KIT $4.50 ea. This new stereo level indicator kit consists of 36 4 -color LED (15 per channel) to indicate the sound level output of your amplifier from -36dB +3dB. Comes with a well - 100W CLASS A POWER AMP KIT designed silk screen printed plastic panel and has a Dynamic Bias Class "A" circuit design makes this unit selector switch to allow floating or gradual output indicating. unique in its class. Crystal clear, 100 watts power output Power supply is 6 12V D.C. with THG on board input will satisfy the most picky fans, A perfect combination with sensitivity controls. This unit can work with any amplifier the TA -1020 low T.I.M. stereo pre -amp. from 1W to 200W! PER Specifications: Kit includes 70 pcs. driver transistors, 38 pcs. matched 4 - $59.50 KIT Output power: 100W RMS into 8 -ohm color LED, all other electronic components. PC board and REGULATED DUAL VOLTAGE 125W RMS into 4 -ohm front panel. SUPPLY KIT Frequency response: 10Hz-100KHz ± 4 ~ 30V DC 800 MA adjustable, fully regulated by T.H.D.: less than 0.008% MARK IV KIT Fairchild 78MG and 79MG voltage regulator I.C. Kit S/N ratio: better than 80dB $31.50 includes all electronic parts, Input sensitivity: IV max. filter capacitors, I.C.. heat Power supply: ± 40V @ 5 amp sinks and P C board. One channel, needs two for stereo MARK V 15 STEPS LED $12.50 PER KIT TA-1000KIT POWER OUTPUT INDICATOR KIT $51.95 All functions same as Mark IV but this is with POWER SUPPLY KIT Power heavy duty aluminum front plate and case. 0-30V D.C. REGULATED transformer Can be easily slot into the front panel of your Uses UA723 and ZN3055 Power TR $24.00 each auto, truck or boat. Operates on 12V DC. output can be adjusted from 0-30y. 2 AMP. Complete with PC board and all electronic parts. Tranformer for Power 50 WATTS AUTO STEREO BOOSTER Supply. 2 AMP 24V x 2 $9.50 BY VERTRONIX 0-30 Power Supply Specifications: 50 watts RMS total (25W + 25W) $10.50 each Frequency Response: ± TA -323 6 WATTS TOTAL 0.5dB. 20Hz ~ 20KHz T.H.D.: 0.2% at full rated 30W + 30W STEREO AMP KIT $41.50 EACH KIT This is a solid state all transistor circuitry with on board output stereo pre -amp for most microphone or phone input. Input Impedance: 20K ohms SOLID STATE STEREO GRAPHIC Power output employs 2 pairs matching Darlington Transis- Crosstalk: Better than 90dB EQUALIZER PRE AMP KIT TA -2500 tors. Driven by the popular 2N3053 Driver Transistors. Model V -Amp 500 Sensitivity: 1.5V for full Specifications: Four built on board controls for; volume, balance, treble REG. PRICE rated output Total Harmonic Distortion: Less than 0.05% and bass. Power supplies requires 48 VET 2.5 amp trans- $119.00 EACH S/N Ratio: Greater than 95dB Intermodulation Distortion: (70Hz:7KHz = 4:1SMPTE former. T.H.D. of less than 0.1% between 100 Hz and OURSPECIALPRICE Speaker Load: 2 ~8 ohms Method) Less than 0.03% 10KHz at full power. (30 Watts + 30 Watts loaded by $55.00 EACH Voltage Supply: D.C. 9~18V Frequency Response: Overall 10Hz N 100KHz +0.5dB. -1dB. * SPECIAL * "FISHER" 30 WATT STEREO AMP RIAA Curve Deviation: (Phono) +0.2dB. -0.2dB MAIN AMP (15W x 2) (30Hz ~ 15KHz) EXCELLENT Kit includes 2 pcs. Fisher PA 301 Channel separation (at rated output 1KHz) Hybrid IC all electronic parts with PC PRICE! Phono. Tuner. Aux and Tape Monitor better than 70dB. Board. Power supply ± 16V DC (not Input sensitivity and impedance (1KHz for rated output) MODEL 001-0034 Included). Power band with (KF 1% ± tie Phono: 2MV 47K ohms Aux: 130MV 50K ohms Transformer (Optional( Super Buy 3dB). Voltage gain 33dB. 20Hz-20KHz. Tuner: 130MV 50K ohms Tape: 130MV 50K ohms $29.50 PER KIT''' Only $18.50 Graphic Equalizer control: 10 Band Slide Control $10.50 EACH 5W AUDIO AMP KIT Frequency Bands: 31.5Hz: G3Hz; 125Hz: 250Hz; 500Hz: 1KHz: 2KHz: 4KHz: 8KHz: 16KHz with LM 380 with Volume Control also on panel selector for Phono. Tuner. Aux 1 and Aux 2. Power Supply 6 I8V DC 200 WATTS CLASS 'A' STEREO POWER ail ONLY Power Supply: 117 VAC Kit comes with all electronic components, transformer. AMP KIT TA -2600 (WITH LED POWER $6.00 EACH instructions and a 19" rack mount type metal cabinet. LEVEL DISPLAY AND RACK MOUNT TYPE CABINET) 2 WATT AUDIO AMP TA -2600 is a kit that combines two sets of TA 1000 class A Pre assembled units. All you need is to hook up the power amplifiers that can give you 100 watts of true power speaker and the volume control. Supply voltage from 9N per channel. The kit also has the latest "V" shape LED 15V D.C. measures only 2" x 31/2 r, making it good for power level display with memory Peak Hold on the front portable or discrete MODEL TA2500 panel. For speaker protection it also has separate electronic speaker protection circuits. Kit comes with the applications. Comes 19" rack $119.00 PER KIT mount type metal cabinet with a professional quality black with hook up data. anodized front panel: all electronic parts and components: ELECTRONIC DUAL PC. boards: filter capacitors and a heavy duty transformer. BUY 2 FOR SPEAKER PROTECTOR Specifications: Power Level Display: Electronic LED type. 12 LED per Curt off when circuit is shorted $4.99 channel from - 18 dB to 0 dB with Peak Hold memory or over load to protect your Power Amplifier: Output power 100 Watts per channel amplifier as well as your speak- into 8 Ohm load: 125 Watts into 4 Ohm load. Total 1 WATT AUDIO AMP ers. A must for OCL circuits. Music power output 250 Watts Max Frequency Response: 10 to All parts are pre -assembled on a mini PC Hz 100 KHz Total Harmonic Distortion: Less than 0.008% Board. Supply Voltage at full power 6~9V D.C. KIT FORM $8.75 EA. Signal/Noise Ratio: better than 80 dB SPECIAL PRICE $1.95 ea. Input Sensitivity: 1V Max. e4 FORMULA INTERNATIONAL INC. SNIPPING ANO NANOUNG CNAROES Urher 55000 purcnane Over MOOD purcruae Send $1.00 i11; Insee Caldornra lo. For Detailed Outsiee Cael 4rciueeexic 3 canaaél 15`. t0, Catalogue Overseas ID'. Oe/ce CANLe1Soleater elkp@,l.00reercocnene Oreers P.cceo 0/ on Vaa or ,, ONLV Nx COD /Slorp lours t0 1 Mw+ tnu Sal VISA' 12603 CRENSHAW BLVD.. HAWTHORNE. CA 90250 MODEL TA -2600 $285.00 FULLY PHONE: (213) 973-1921 (213) 679-5162 $ 225.00 KIT FORM ASSEMBLED

124

www.americanradiohistory.com DIGITAL FOR COMMERCIAL FREE TIMER/CLOCK No FCC license CRYSTAL 24 Hour preset time to turn on or off TV BOX BUILDERS required. CONTROLLED 12 Hour green 0.5" display for time MC 1358 $2.50 LM 7815 $1.20 OUR PRICE WIRELESS. operated on 12^' 16V A.C. MC 1350 $2.00 NE 565 $2.00 MICROPHONE The whole timer is self $49.50 MC 1330 $3.00 Connectors Set $1.00 contained in a compact ADDITIONAL SYSTEM LM 1458 $1.00 I.C. Socket Set $2.00 plastic case (as seen in MICROPHONE Transmitter: FET mic for flat 30 Úv1380 i $2.00 Matching Transformer $1.40 photo). Designed for VTR (TRANSMITTER) Sanyo UHF Tuner $35.00 Tolriod Coils ..'18 KHz response extra con- with push button switch AVAILABLE trolled 49MHz AM Band for drift - Capacitors Set $12.50 (Set of 4) $3.00 for easy setting. Limited AT $28.00 EACH free 100 MW Resistors Set $2.00 Speaker Cabinet $12.95 performance. quantity available. Trim Pots: Transformer output (range approx. t'A mile) MODEL VEQ 0143 for reliable long range Trim Caps Set $13.50 18V 800MA $3.00 NOW ONLY $12.94 Pots and Knobs $2.00 transmission. Powered by SANYO ANTENNA SIGNAL BOOSTER a 9V radio battery (in- We sell you all the above components in a package for This Booster is specially designed for UHF Channels cluded). $125.00 and you will receive a free predrilled P.C. board (14-83). After installed this unit (between the antenna Input Receiver: Extra controlled and instructions at no charge! cable and the UHF tuner) will have a minimum of 10dB locks on 49MHz trans- gain. that is approximately 2 times better than what you are mitter signal. SANYO UHF VARACTOR TUNER seeing now. Ideal for those who live in apartments that can- With on panel not put up an outdoor antenna. Size is small; only 2" x For UHF CH 14 83 so MURA WMS-49 VU meter It/z" x 1". Supply voltage Is 15 VDC. Tuning voltage +1V^'+28V D.C. Input impedance 75 monitors the signal strength from the microphone. Stan- OHM. I.F. band width 7 r 16 MHz. Noise figure 11.5dB * NEW ITEM * dard phone jack outlet connection to a P.A. or other phone MAX. Size 25/8' x l'/s" x 3/4" Supply voltage 15V D.C. input. 9V battery included. This professional set is ideal for Sound I.F. = 58.0 MHz. MODEL 001-0076 on stage, in field, church, in house or outdoor use. Video I.F. = 62.5 MHz. ...nw . SUPER FM WIRELESS MIC KIT - $12.50 EACH MARK III te7s-40`' All units are brand new This new designed circuit uses high from Sanyo. 13 FUNCTIONS LCD TIME MODULE FEQ. FET transistors with 2 stages MODEL 115 -B -405A Displays month, date and pre amp. Transmits FM Range (88- $35.00 EACH day of the week 120 MHz) up to 2 blocks away and Displays hour, minute and with the ultra sensitive condensor second microphone that comes with the AM, PM Indicator Tuner is the most important part for the circuit. Don't let kit, allows you to pickup any sound Alarm 1 and Alarm 2 (Inde- those $19.00 tuners fool you! pendent) within 15 ft. away! Kit includes all 10 Hours Stop Watch electronic parts. OSC coils, and TV GAME BOARD 12 Hours presettable count P.C. Board. Power supply 9V D.C. down time PLAYS 4 GAMES: TENNIS; HOCKEY. HANDBALL MODEL 001-0062 FMC -105 $11.50 PER KIT AND JAI -ALAI. Hour Charm Indicator Back light by touch of the All boards complete with all parts ready to play. Requires $7.94 EACH switch WEM -36 FM WIRELESS MICROPHONE 6C size batteries and a small speaker for sound effects. These modules are brand new and made by LITRONIX. TEET MODEL WEM -36 is a factory assembled FM The boards were surplus from a famous game manufac- Designed for a man's watch. Can be used for many applica- wireless microphone powered by two AA size batteries. turer. They will play on all US standard black and white or tions. Comes with 2 silver batteries and the ceramic round Transmits in the range of 88-108 MHz with 3 transistor transducer. color TV sets. (Regular price for these games were $39.50 circuits to meet with F.C.C. part 15 regulations. Element is each) OUR PRICE ONLY $6.50 EACH MATCHED PAIR POWER TRANSISTORS built in a plastic tube type case with an omni-directional BY MOTOROLA electret condenser microphone unit. By using a standard TENNIS JAI -ALAI FM radio. signal can be heard anywhere on a one -acre lot. MJ2955 PNP150 Watts BV=60 V $3.50 Sound quality was judged "very good." 2N3055 NPN I.0 =15 A per pair

MJE2955 PNP90 Watts BV=60 V $3.00 MODEL WEM-36 EACH MJE3055 NPN ' I.C.=10 A per pair $16.50

MJ15003 NPN250 Watts BV=140 V $12.00 WHISTLE ACTIVATED SWITCH BOARD PART #57456 MJ15004 PNP l.C.=20 A per pair All boards are pre -assembled and tested. Your whistle to its FET condenser microphone from a distance. as far as HOCKEY HANDBALL All above parts guaranteed to be prime and come with 30 feet away (sensitivity can be easily adjusted) will turn data sheets. the switch on. then match your whistle to it again. then it turns off. Ideal for remote control toys. electrical appliance ELECTRONIC PIN BALL MACHINE MUFFIN FANS FOR EQUIPMENT COOLING such as lights. coffee pots. TV. Hi -Fie radio or other These fans are pulled out from projects. Unit works on 9V D.C. used computers. But carefully That sounds and plays like the cleaned by ultrasonic cleaner. real thing. All units are brand All in "like -new" condition. new but without the case. Func- Size 4 11/16" x 1-1/2" x tions of the game include 4 11/16". double flipper control- kicker MODEL MF505 MODEL 968 control. 1-4 players. 3 speed $9.50 EACH ball control, tilt switch. auto- $4.50 EACH matic score. extra bonus cave and many more. All solid state FLUORESCENT LIGHT DRIVER KIT ULTRASONIC with LED panel, no moving 12V DC POWERED SWITCH KIT parts. Requires 9V battery to Lights up 8^'15 Watt Fluo- operate. speaker not included. rescent Light Tubes. Ideal for camper, outdoor, auto or boat. Kit includes high voltage coil. power transistor. A perfect gift for yourself or friends. heat sink all other electronic Kit includes the Ultra Sonic Transducers. 2 PC Boards for SPECIAL $8.99 EACH SPEAKER $1.25 EACH parts and PC Board. light transmitter and receiver. Alt electronic parts and instruc- $6.50 Per Kit tube not included! tions. Easy to build and a lot of uses such as remote control ELECTRONIC MUSICAL TELEPHONE for TV, garage door. alarm system or counter. Unit REST KIT PRESS -A -LIGHT SELF operates by 9.12 DC. $15.50 I his telephone rest can he used as a door charm. an GENERATED FLASHLIGHT audible indicator and for many other sound projects. The Never worry about battery. EXCLUSIVE!$3.95 ea. special custom made I.C. is pre programmed with 4 ELECTRONIC SWITCH KIT because it has none! Easy to musical tunes. Kit comes with a nice looking plastic case. carry in pocket and handy to pre -drilled P.C. board. volume control. special sound I.C. CONDENSER TYPE use. Ideal for emergency light. speakers and all electronic components and instructions. Touch On Touch Off Ideal for home or school projects. It generates its own electricity uses 7473 I.C. and by squeezing grip lever. Put 12V relay BUY one in your car. boat. camper or home. You may need it $5.50 each NOW! some time! Model F-179 SPECIAL 4le FORMULA INTERNATIONAL INC. SHIPPING AND HANDLING CHANGES Send $1 .00 ume 550 oo purchase Over 550m purchase PRICE! For Detailed mill orcloaasn

ONLY - ,: orner sroaorearn Resroenb Aa0 G. Sabº ra. . árors AccaPlea on v:ºa a me oNLv. No e o D.isbra warº Ior n+o" Iw sal VISA' $15.50 PER KIT 12603 CRENSHAW BLVD.. HAWTHORNE. CA 90250 PHONE: (213) 973-1921 (213) 679-5162

CIRCLE 64 ON FREE INFORMATION CARD

www.americanradiohistory.com Lione O CAPACITANCE METER .1pFto999KuF THE SYSTEM 20 in o FREQUENCY COUNTER 35MHz MICROWAVE TV RECEPTION kit O SQUARE WAVE GEN. 1Hz to 99KHz- AT IT'S BEST!! O OHMMETER-3.58MHz Xtal - Regulated PS- Five RX-2300 Assembled Down Converter .8" Readouts -Low Cost TTL Circuits -Automatic Power Supply / Antenna Switch Decimal Placement -Be AMAZED -Build it for 25" Parabolic Antenna All Coaxial Cables :28.15+ $60 or less. I Purchase the plans,drilled P.C. Full Year Warranty board 4-3/4" by 6-3/4" and front panel decal $5.00 shipping for $2'.791 BAGNALL ELECTRONICS, Refund_ M hAvNATIM abte 22551618 97th Avenue North 179 May Street, Fairfield, Conn. 06430 TEM Corcoran, Minnesota 55374 LEARN ABOUT taSv V a adz S-100 computers are the next logical step up after personal' computers, whether for business, professional, or scientific applications. These three books are a must for technicians, students, systems integrators, or anyone who wants to know more about S-100 computers. 'Interfacing to 5-100/ IEEE 696 Microcomputers', by Sol Libes and Mark Garetz. Spells out operating requirements and characteristics with clarity and precision. 17 chapters cover busing techniques, parallel and serial interfacing, handshaking, bus signals and timing relationships, I/O ports, interrupts, A/D and D/A conversion, much more. Osborne/McGraw-hill; softcover; 321 pages. $15.00 `Product User Manuals 1975-1980, Volume 1', by CompuPro. With schematics, test routines, operating information for 29 CompuPro products (RAM and ROM memories, motherboards, CPU 8085/8088 dual processor board, CPU -2, interfacers, etc.). Also defines and explains the S-100 bus. Excellent reference on memories and CPU boards. Softcover; 8.5in x l lin. format; 256 pages; $20. 'Product User Manuals, Volume 2', by CompuPro. Similar to above, but covers System Support 1, Disk 1, RAM 17 CMOS memory, Interfacer 3, STD RAM, STD CPU, STD motherboard, and and more. Softcover; 8.5in. x 1 lin. format; 307 pages; $25.

division om u ProTM ELECTRONICS TERMS: Cal res add tax. Allow 10% shipping; excess refunded. VISA. end Mastercard® orders ($25 minimum) call (415) 562-0636, 24 hrs. Include street edress for UPS. Prices OAKLAND AIRPORT, CA 94614-0355 (415)562-0636 subject to change without notice. CIRCLE 77 ON FREE INFORMATION CARD ------a-stl------sue Electronics Paperback Books Quality Books on Computers and Other Subjects Check Off The Ones You Want!

y95 ci tCts O ' PpO,Ncuo1 O°wel

puss ELECTRONIC TECHNOLOGY TODAY INC. 5/82 P.O. Box 83. Massapequa Park. NY 11762

Number of books ordered Total Price of Books Sales Tax INY Slate Residents only) Shipping and Handling

160c 1 or 2 books 25c each addl bdakl TOTAL ENCLOSED Name Address Slate Lip PRICES GOOD UNTIL JULY 30, 1982 City t am' moo Ram taum-mi lie 8lImam mi81tm ism 8181en 126

www.americanradiohistory.com MICROWAVE EQUIPMENT and KITS ANTENNA parabolic fiberglea antenna e Hobbyists, "Users", 20", approx. 20db gain $49.95: HANTENT II hi -gain 4 transistor 2.1-2.4 OSCILLOSCOPE Small System Houses... CH: to VHF TV ch. 2-6, down : converter w/metal case. KIT 39.95: We offer top line, pro qualitÿ off lease, used ASSEMBLED 6 TESTED 59.95: POWER II precision 8-15VDC power supply 8 refurbished equipment formerly available for down converters.. KIT 24.95: only to giant corporations... ASSEMBLED 6 TESTED 39.95: MICROWAVE RECEIVING SYSTEM - ALL High Speed Chain. Drum. Band & Matrix Line THREE - ASSEMBLED AND TESTED 124.95: Printers & Terminals Duality Mini -Diskette. Diskette. Disk & Storage Module Drives 1/4 to 300 mbytes SUPER LED's CRT Terminals. Printing Terminals. CRT 2anp. rotin w/heat sink Monitors ME2 IR a 25A pulse Small & Medium Site Minicomputer. Word 6-3 Processors & Peripherals MES IR stud W p R 4.95 e dl t RESISTOR SALE THIS MONTH'S SPECIALS! per100 (one value) 2 .25W 5% carbon film- $1.50 HITACHI Reg. Sale all standard values from $12 per 1000 V-1518 Single 15MHz/ImV ... 570 -480- 2.7to4.7Mohms V-1528 Dual 15MHz/lmV ... 735 -699- Complete WANG PCS-IIA V-202 Dual 20MHz/ImV ... 850 x697 MINICOMPUTER SYSTEM! SPECIALS V-3028 Dual 30MHz/lmV ... 995 -81-5- 8085 NEC CERAMIC 40 PIN CPU CHIP $6.95 V-352 Dual 35MHz/lmV ... 1150 Ob0 Off -lease refurbished 8 1015290.1 NSC 16K/1 DYNAMIC RAM(4116) V-5508 Dual 50MHz/lmV 1745 1490- eligible for Mfr's mainten- e. 2.95 ... 82758 INTEL EPROM 1K/8 8.95 V-1050 Quad 100MHz/0.5mV .2390 1A95- ance. Many, many exciting TRIAC 8A -600V T0220 RCA .75 features and capabilities SIDLTEC include VOX- MICROPHONE,AMP,2A SCR,PC BD .95 515-1 Single 15MHz/lmV 495 Call 401(24 U/L Display H11A2 G.E. OPTO ISOLATOR 6 PIN DIP .25 515-2 Dual 15MHz/ImV 595 Call 5101 256X4 CMOS RAM 22 PIN DIP 4.95 32 Special Function Keys 520 Dual 2OMHz/lmV 695 Coll 48K Basic in Roms. 16K Ram TRIAC 25AMP 400V ON 3X6" HEAT SINK 2.95 530 Dual 30MHz/lmV 895 Call Dual Shugart Mini Floppy's 7402 TTL QUAD 2 IN NOR GATE DIP .10 Cºmpacl. Sell -Contained 7430 TTL 8 IN NAND GATE DIP .10 LEADER Basic "keyword. Keyboard Wang "Basic" Operating 7440 TTL DUAL 4 IN NAND BUFFER DIP .10 L80-513 Single 10MHz/lmV.. , . 550 Call List Over $6000. System TO -92 PNP TRANSISTOR PAK 100 PRIME L80-514 Dual 10MHz/lmV 695 Call 110 VAC.60 Hz 5.00 .... Dual Printer Ports 747 DUAL 741 OP -AMP 14 PIN DIP .50 L60 -508A Dual 2OMHz/10mV ... 880 Call 'Centronics 1/01 LH0021 NSC 1 AMP OP -AMP 8 PIN TO -3 5.00 LBO -520A Dual 35MHz/5mV.... 1250 Call 2504T 1024 BIT DYN. SHIFT REG.TO-5 1.00 LBO -515B Dual 30MHz/5mV .... 1580 Call WANG PCS IIA $2790 ea. 2416 INTEL 256X64 CCD SERIAL MEN. 2.50 Add S20 00 for Stripping Crate Pay Shipping on Delivol y 5244 INTEL CCD DRIVER 3.00 FREE FREIGHT for order paid with cashier's check or money order. Above prices are for prepaid order WANG/DIABLO "WP" `rd< 'r sta r m r only. VISA/MC accepted. Allow 2 weeks to clear b< 1e U.S. funds {r personal checks. California residents, odd 6% soles ' ,cl.d BAC 6 MC a BOX 41778 ode.sm I° DAISY PRINTER °

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CRYSTALS EPROMS Each 8 pca 6502 32.768 KHZ 3.95 1702 256 x 8 (1ns) 4.95 4.50 6502 6.95 1.0 MHZ 4.95 r.1FIY 2708 1024 x 8 (450ns) 2.99 2.75 SPECifiLS 6502-A 12.95 1.8432 4.95 2758 1024 x 8 (5V) (450ns) 9.95 8.95 6504 6.95 2.0 3.95 16K APPLE* TMS2516 2048 x 8 (5V) (450ns) 6.95 5.95 RAM CARD 6505 8.95 2.097152 3.95 2716 2048 x 8 (5V) (45ons) 5.50 4.95 6507 9.95 2.4576 3.95 * Upgrade your 48K Apple II to full 2716-1 2048 x 8 (5V) (3500s) 9.00 8.50 6520 4.35 3.2768 3.95 64K. TMS2716 2048 x 8 (450ns) 9.95 8.95 6522 9.95 3.579545 3.95 TMS2532 4096 x 8 (5V) (450ns) 12.95 11.95 * Fully software and hardware com- 6532 14.95 4.0 3.95 2732 4096 x 8 (5V) (450ns) (200ns) CALL 6551 11.85 5.0 3.95 patible with Apple language card 2764 8192 x 8 (5V) (4500s) CALL 5.0688 3.95 and microsoft 280 card. DYNAMIC RAMS 100 pca 5.185 3.95 * Eliminates the need for Applesoft 5.7143 3.95 Z80 or Integer Basic ROM card when 4027 4096 n 1 (250ns) 2.50 2.00 6.5536 3.95 used in Z80 4116-120 16,384 x 1 (120ns) 8/29.95 CALL 8.0 3.95 conjunction with DOS 3.3. -CPU 8.95 Z80A-CPU 6.00 4116-150 16,384 x 1 (15Ons) 8/18.95 1.95 10.0 3.95 Allows you to run Apple Fortran * or Z80-P10 6.50 4116-200 16,384 x 1 (200ns) 8/15.95 1.80 14.31818 3.95 Pascal. 4116-300 16,384 x 1 (300ns) 8/14.95 1.75 18.0 3.95 Z80A-P10 6.00 Z80-CTC 5.95 4164 64,536 x 1 (200ns) CALL 18.432 3.95 * Available as bare board, kit, or com- Z80A-CTC 8.65 20.0 3.95 pleted and tested board. STATIC RAMS 100 pea 22.1184 3.95 Z80-DART 15.25 32.0 3.95 Z80A-DART 18.75 x 4 BARE BOARD $ 40.00 2101 256 (450ns) 1.95 1.85 Z80-DMA 17.50 2102-1 1024 x 1 (450ns) .89 .85 KIT 89.95 Z80A-DMA 27.50 21 L02-4 1024 x 1 (LP) (450ns) 1.29 1.15 Z80-S10/0 23.95 21 L02-2 1024 x 1 (LP) (250ns) 1.69 1.55 ASSEMBLED & Z80A-S10/0 28.95 2111 256 x 4 (450ns) 2.99 2.49 MISC. AY5-2376 TESTED 109.95 Z80-S10/1 23.95 2112 256 x 4 (450ns) 2.99 2.79 12.50 Z80A-S10/1 28.95 2114 1024 x 4 (450ns) 8/16.95 1.95 11C90 13.95 6883 SAM 24.95 Z80-510/2 23.95 2114L-2 1024 x 4 (LP) (200ns) 8/19.95 2.35 XR2206 4.95 Z80A-S10/2 28.95 2114L-3 1024 x 4 (LP) (300ns) 8/18.95 2.25 3242 7.95 RS232 FEMALE 3.49 3480 9.00 Z80 -S10/09 17.95 2114L-4 1024 x 4 (LP) (450ns) 8/17.95. 2.10 MC4024 3.95 RS232 RIGHT ANGLE Z80A-510/9 22.95 2147 4096 x 1 (55ns) 9.95 CALL MC4044 4.50 FEMALE TMS4044-4 4096 x 1 (450ns) 3.49 3.25 4.95 7103 9.50 Z80B-CPU 18.95 TMS4044-3 4096 x 1 (3000s) 3.99 3.75 RS232 7106 9.95 MALE 2.99 Z80B-CTC 17.95 TMS40L44-2 4096 x 1 (LP) (2000s) 4.49 4.25 7107 12.95 ZBOB-P10 17.95 TM M2016 2048 x 8 (200ns) (15Ons) CALL RS232 HOOD .99 76477 HM6116 2048 x 8 (20005) (15Ons) (120ns) CALL 3.95 Specials end May 31, 1982. Please state Z8671 39.95 8038 3.95 "May Specials" when ordering. LP = LOW POWER 95H90 7.99 26132 34.95 9602 1.50 CMOS 74LS00 SERIES DISC CON- 74C00 .35 74C374 2.75 4019 .45 4098 2.49 74LS166 2.40 74LS293 1.85 TROLLERS 74CO2 .35 74C901 .80 4020 .95 4099 1.95 74LS00 25 74LS85 1.15 74LS168 1.75 74LS295 1.05 1771 24.95 74C04 .35 74C902 .85 4021 .95 14409 12.95 74LSO1 25 74LS86 .40 74LS169 1.75 74LS298 1.20 1791 36.95 74C08 .35 74C903 .85 4022 1.15 14410 12.95 74LS02 .25 74LS90 .65 74LS170 1.75 74LS324 1.75 1793 44.95 74C10 .35 74C905 10.95 4023 35 14411 11.95 74C14 1.50 74C906 4024 .75 14412 12.95 74LS03 .25 74LS91 .89 74LS173 .80 74LS352 1.55 1797 54.95 .95 74LSO4 .25 74C20 .35 74C907 1.00 4025 .35 14419 4.95 74LS92 .70 74LS174 .95 74LS353 1.55 UPD765 39.95 74LS05 .25 74LS93 .65 74LS175 .95 74LS363 1.35 74C30 .35 74C908 2.00 4026 1.65 4502 .95 74LS08 .35 74LS95 .85 74LS181 2.15 74LS364 1.95 UARTS 74C32 .50 74C909 2.75 4027 .65 4503 .65 74LS10 .25 74LS96 .95 74LS189 9.95 74LS365 .95 74C42 1.75 74C910 9.95 4028 .80 4508 1.95 74LS11 .35 74LS107 .40 74LS190 1.00 74LS366 .95 AY3-1014 6.95 74C48 2.10 74C911 10.00 4029 .95 4510 .95 74LS12 .35 74LS109 .40 74LS191 1.00 74LS367 .70 AY5-1013 3.95 74C73 .65 74C912 10.00 4030 .45 4511 .95 74LS13 .45 74LS112 .45 74LS192 .85 74LS368 .70 TR1602 4.95 74C74 .85 74C914 1.95 4034 2.95 4512 .95 74LS14 1.00 74LS113 .45 74LS193 .95 74LS373 .99 1M6402 7.95 74C76 .80 74C915 2.00 4035 .85 4514 1.25 74LS15 .35 74LS114 .50 74LS194 1.00 74LS374 1.75 74C83 1.95 74C918 2.75 4040 .95 4515 2.25 74LS20 .25 74LS122 .45 74LS195 .95 74LS377 1.45 INTERFACE 74C85 1.95 74C920 17.95 4041 1.25 4516 1.55 74LS21 .35 74LS123 .95 74LS196 .85 74LS378 1.18 74C86 .95 74C921 15.95 4042 75 4518 1.25 74LS22 .25 74LS124 2.99 74LS197 .85 74LS379 1.35 8726 1.69 74C89 4.50 74C922 5.95 4043 .85 4519 1.25 74LS26 .35 74LS125 .95 74LS221 1.20 74LS385 1.90 8728 2.49 74C90 1.75 74C923 5.95 4044 .85 4520 1.25 74LS27 .35 74LS126 .85 74LS240 .99 74LS386 .65 8795 .99 74C93 1.75 74C925 6.75 4046 .95 4522 1.25 74LS28 .35 74LS132 .75 74LS241 .99 74LS390 1.90 8796 .99 74C95 1.75 74C926 7.95 4047 95 4526 1.25 74LS30 .25 74LS136 .55 74LS242 1.85 74LS393 1.90 8T97 .99 740107 1.00 74C927 7.95 4049 55 4527 1.95 74LS32 .35 74LS137 .99 74LS243 1.85 74LS395 1.65 8798 .99 74C150 5.75 74C928 7.95 4050 .55 4528 1.25 74LS33 .55 74LS138 .75 74LS244 .99 74LS399 1.70 DM8131 2.95 74C151 2.25 74C929 19.95 4051 .95 4531 .95 74LS37 .55 74LS139 .75 74LS245 1.90 74LS424 2.95 DS8836 1.29 74C154 3.25 74C930 19.95 4053 .95 4532 1.95 74LS38 .35 74LS145 1.20 74LS247 .76 74LS447 .37 74C157 1.75 4000 .35 4060 1.45 4538 1.95 74LS40 .35 74LS147 2.49 74LS248 1.25 74LS490 1.95 CLOCK 74C160 2.00 4001 .35 4066 .75 4539 1.95 74LS42 .55 74LS148 1.35 74LS249 .99 74LS668 1.69 CIRCUITS 74C161 2.00 4002 .25 4068 .40 4543 2.70 74LS47 .75 74LS151 .75 74LS251 1.30 74LS669 1.89 740162 2.00 4006 .95 4069 .35 4555 .95 74LS48 .75 74LS153 .75 74LS253 .85 74LS670 2.20 M M 5369 3.95 760163 2.00 4007 .29 4070 .35 4556 .95 74LS49 .75 74LS154 2.35 74LS257 .85 74LS674 9.65 MM5375 3.95 74C164 2.00 4008 .95 4071 .30 4581 1.95 74LS51 .25 74LS155 1.15 74LS258 .85 74LS682 3.20 MSM5832 7.45 740165 2.00 4009 .45 4072 .30 4582 1.95 74LS54 .35 74LS156 .95 74LS259 2.85 74LS683 2.30 7207 7.50 74C173 2.00 4010 .45 4073 .30 4584 .95 74LS55 .35 74LS157 .75 74LS260 .65 74LS684 2.40 7208 15.95 74C174 2.25 4011 .35 4075 .30 4585 .95 74LS63 1.25 74LS158 .75 74LS266 .55 74LS685 2.40 74C175 2.25 4012 .25 4076 .95 4702 12.95 74LS73 .40 74LS160 .90 74LS273 1.65 74LS688 2.40 74C192 2.25 4013 .45 4078 .30 4724 1.50 74LS74 .45 74LS161 .95 74LS275 3.35 74LS689 2.40 CONVERTERS 740193 2.25 4014 .95 4081 .30 80007 .95 74LS75 .50 74LS162 .95 74LS279 .55 81LS95 1.69 74C195 2.25 4015 .95 4082 30 80095 .85 74LS76 .40 74LS163 .95 74LS280 1.98 81LS96 1.69 MC1408 L8 4.95 74C200 5.75 4016 .45 4085 .95 80C96 .95 74LS78 .50 74LS164 .95 74LS283 1.00 81LS97 1.69 DAC-0800 4.95 74C221 2.25 4017 1.15 4086 .95 80097 .95 74LS83 .75 74LS165 .95 74LS290 1.25 81LS98 1.69 ADC -0804 4.95 74C373 2.75 4018 .95 4093 95 80098 1.20

HOURS: Mon. - Fri., 9 to 5; Sat., 11 to 3 VISIT OUR RETAIL STORE!

JDR MICRODEVICES, INC. TERMS' For shipping include $2.00 for UPS ground, $3.00 1224 So. Bascom Ave. for UPS Blue Label air. $10.00 minimum order. Bay Area VISA residents add 61/2% sales tax. California residents add 6% San Jose, CA 95128 sales tax. We reserve the right to limit quantities and sub- 800-538-5000 800-662-6279 (CA) stitute manufacturer. Prices subject to change without notice. Send SASE for complete list. (408) 995-5430 Telex 171-110

128

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2716 EPROMS 450NS (5V) 81`t.95 ea.

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r r IC SOCKETS 8000 8200 TV APPLE* FAN $69.00 1.99 100 CIRCUITS EXTRA PLUG-IN CARDS CAN 16.95 45.00 8035 8202 CAUSE YOUR APPLE TO 8 pin ST .13 .11 MC1330 1.89 8039 19.95 8205 3.50 OVERHEAT 14 pin ST .15 .12 8080A 3.95 8212 1.85 MC1350 1.29 16 pin ST .17 .13 MC1358 1.79 ULTRA -QUIET APPLE FAN 8085 12.95 8214 3.85 18 pin ST .20 .18 8085A-2 16.95 8216 1.80 LM380 1.29 DRAWS COOL AIR THROUGH YOUR COMPUTER 20 pin ST .29 .27 8086 99.95 8224 2.50 LM386 1.50 22 pin ST .30 .27 8088 39.95 8226 1.80 LM565 .99 ELIMINATES DOWN TIME 24 pin ST .30 .27 8155 11.95 8228 4.90 LM741 .29 SAVES REPAIR CHARGES 28 pin ST .40 .32 LM1310 8156 11.95 8237 19.95 2.90 40 pin ST .49 .39 8185 29.95 8238 4.95 LM1800 2.99 INCREASES RELIABILITY ST = SOLDERTAIL 8185-2 39.95 8239 4.85 LM1889 2.49 CLIPS ON - NO HOLES OR 8741 39.95 8243 4.45 SCREWS 8 pin WW .59 .49 8748 29.95 8250 14.95 COLOR MATCHES APPLE 14 pin WW .69 .52 8755 44.9 8251 4.75 16 pin WW .69 .58 LONG LIFE. LOW NOISE 8253 9.25 r 18 pin WW .99 .90 EPROM ERASERS MOTOR 8253-5 9.85 20 pin WW 1.09 .98 8255 4.75 PE -14 78.50 22 pin WW 1.39 1.28 8255-5 5.25 24 pin WW 1.49 1.35 PE -14T (with timen 108.50 r 6800 8257 8.75 28 pin WW 1.69 1.49 8259 6.90 PE -24T (with timen 154.50 40 pin WW 1.99 1.80 6800 5.70 8272 39.95 WW = WIREWRAP 6802 10.95 8275 29.95 ALL ARE HIGH QUALITY UNI -S ENCLOSED IN `APPLE IS A TRADEMARK BLACK ANODIZED ALUNINJM ENCLOSURE.) 6808 9.95 8279 9.50 LA OF APPLE COMPUTER INC. CONNECTORS 6809 24.95 8279-5 10.50 6809E 29.95 8282 6.65 RS232 MALE 3.25 6810 4.60 8283 6.65 RS232 FEMALE 3.75 RS232 HOOD 1.25 6820 4.95 8284 5.70 800-538-5000 TRANSISTORS 6821 4.95 8286 6.65 r S-100 ST 3.95 6828 14.95 8287 6.50 S-100 WW 4.95 PN2222 10/1.00 100/ 8.99 6834 16.95 8288 25.00 800-662-6279 6840 14.95 `8289 49.95) (CALIFORNIA RESIDENTS) 2N2222 .25 50/10.99 DIP SWITCHES 2N2907 .25 50/10.99 6843 42.95 2N3055 .79 10/ 6.99 4 POSITION .85 6844 44.95 CALL JDR BEFORE 10U BUY! 2N3904 10/1.00 100/ 8.99 5 POSITION .90 6845 16.95 WE WILL BEAT ANY CON1PE-ITORS' PRICES 10/1.00 100/ 8.99 6 POSITION 90 6847 15.95 2N3906 1N4148 (1N914) 25/ 1.00 L7 POSITION 95 6850 4.75 11N4004 10/ 1±32.4 8 POSITION 95 6852 5.75 r VOLTAGE REG's 6860 10.95 r LINEAR, 6862 11.95 LM301 V .34 7805T .79 7905T .89 LM308V 98 6875 6.95 7808T .99 7912T .89 6880 2.95 LM309K 1.49 r- 7400 SERIES 7812T .79 7915T 1.19 LM311 .64 78151 .99 7924T 1.19 7400 .19 7451 .23 74136 .50 74186 18.50 68B00 10.95 LM 317T 1.95 7824T .99 7401 .19 7453 23 74141 .65 74190 1.15 68B21 12.95 LM317K 3.95 7402 7454 .23 74142 2.95 74191 1.15 68B50 12.95,, LM318 1.49 .19 7805K 1.39 7905K 1.49 LM323K 4.95 7403 .19 7460 .23 74143 2.95 74192 .79 7812K 1.39 7912K 1.49 LM324 .59 7404 .19 7470 .35 74144- 2.95 74193 .79 7815K 1.39 79LO5 .79 LEDS LM337K 3.95 7405 .22 7472 .29 74145 .60 74194 .85 78L05 .69 79L12 .79 LM339 .99 7406 .22 7473 .34 74147 1.75 74195 .85 78L12 .69 79L15 .79 LM377 2.29 7407 .22 7474 .35 74148 1.20 74196 .79 Jumbo Red 10/1.00 78L15 .69 LM380 1.29 7408 .24 7475 .49 74150 1.35 74197 .75 Jumbo Green 6/1.00 LM317K 3.95 LM386V 1.50 7409 .19 7476 .35 74151 .65 74198 1.35 Jumbo Yellow 6/1.00 LM309K 1.49 LM323K 4.95 LM555V .39 7410 .19 7480 .59 74152 .65 74199 1.35 5082-7760.43'CC .79 LM317T 1.95 LM337K 3.95 LM556 .69 7411 .25 7481 1.10 74153 .55 74221 1.35 MAN74.3'CC .99 LM565 .99 7412 .30 7482 .95 74154 1.40 74246 1.35 MAN72.3'CA .99 LT= TO -220 K = TO -3 L = TO 92 LM566V 1.49 7413 .35 7483 .50 74155 .75 74247 1.25 LM567V 1.29 7414 .55 7485 .65 74156 .65 74248 1.85 L M 723 .49 7416 .25 7486 .35 74157 .55 74249 1.95 74SÓ0 SERIES LM 733 .98 7417 .25 7489 4.95 74159 1.65 74251 .75 r LM741V .29 7420 .19 7490 .35 74160 .85 74259 2.25 LM747 .79 7421 35 7491 .40 74161 .70 74265 1.35 74S00 .44 74S74 .69 74S163 3.75 74S257 1.39 LM748V .59 7422 29 7492 .50 74162 .85 74273 1.95 74S02 .48 74S168 4.65 74S258 1.49 74S85 2.39 LM 1310 2.90 7423 29 7493 .49 74163 .85 74276 1.25 74503 .48 74S169 74S260 1.83 74S86 1.44 5.44 MC1330)/ 1.89 7425 .29 7494 .65 74164 .85 74279 .75 74SO4 .79 1.59 74S174 1.09 74S274 19.95 74S112 MC1350V 1.29 7426 29 7495 .55 74165 .85 74283 2.00 74S05 .79 745175 74S113 1.98 1.09 74S275 19.95 MC1358 1.79 7427 .29 7496 .70 74166 1.00 74284 3.75 74S08 .48 74S181 4.47 74S280 74S114 1.50 2.90 LM1414 1.59 7428 .45 7497 2.75 74167 2.95 74285 3.75 74S09 .98 745182 2.95 74S287 4.75 74S124 2.77 LM 1458V .69 7430 .19 74100 1.00 74170 1.65 74290 .95 74S10 .69 745188 3.95 74S288 4.45 74S132 1.24 LM 1488 .99 7432 .29 74107 .30 74172 5.95 74293 .75 74511 .88 74S189 14.95 74S289 6.98 745133 .98 LM1489 .99 7433 .45 74109 .45 74173 .75 74298 .85 74S15 .70 .69 745194 2.95 74S301 6.95 74S134 LM 1800 2.99 7437 .29 74110 .45 74174 .89 74351 2.25 74S20 .68 745135 1.48 74S195 1.89 74S373 3.45 LM 2.49 7438 .29 74111 .55 74175 .89 74385 .65 74S22 .98 74S196 4.90 74S374 3.45 74S138 1.08 LM3900 .59 7440 .19 74116 1.55 74176 .89 74366 .65 74S30 .48 74S197 4.25 74S381 7.95 74S139 1.25 LM3909V .98 7442 .49 74120 1.20 74177 .75 74367 .65 74S32 .98 745201 14.95 74S387 5.75 74S140 1.45 LM3914 3.95 7443 .65 74121 .29 74178 1.15 74368 .65 74S37 1.87 74S225 8.95 74S412 2.98 74S151 1.19 LM3915 3.95 7444 .69 74122 .45 74179 1.75 74376 2.20 74S38 1.68 745240 3.98 74S471 9.95 74S153 1.19 LM3916 3.95 7445 69 74123 .55 74180 .75 74390 1.75 74S40 .44 1.19 74S241 3.75 74S472 16.85 745157 75451V .39 7446 .59 74125 .45 74181 2.25 74393 1.35 74S51 .78 74S244 3.98 74S474 17.85 74S158 1.45 75452V .39 7447 .69 74126 .45 74182 .75 74425 3.15 74564 .79 74S251 1.90 74S482 15.60 74S161 2.85 75453V .3.9j 7448 .69 74128 .55 74184 2.00 74426 .85 74S65 1.25 745162 3.70 74S253 7.45 745570 7.80 .19 ' 74185 2.00 74490 2 55 74S571 7.80411 `7450 74132 .45

HOURS: Mon. - Fri., 9 to 5; Sat. 11 to 3 VISIT OUR RETAIL STORE! JDR MICRODEVICES, INC. TERMS: For shipping include $2.00 for UPS Ground, $3.00 for UPS Blue Label Air. $10.00 minimum order. Bay Area 1224 S. Bascom Ave. residents add 61/2% sales tax. California residents add 6% 111861@f charge San Jos3, CA 95128 sales tax. We reserve the right to limit quantities and substitute manufacturer. Prices subject to change without 3. 800-538-5000 800-662-6279 (CA) notice. Send SASE for complete list. (408) 995-54.30 Telex 171-110

CIRCLE 65 ON FREE INFORMATION CARD

www.americanradiohistory.com ADVERTISING INDEX 41 Netronics 107 C 0 25 Non Linear Systems 17 45 North American Soar 97 CABLE TV RADIO -ELECTRONICS does not assume 39 ORA Electronics 106 any responsibility for errors that may 81 P.P.G. Electronics 123 CONVERTERS appear in the index beiów. 43 Pac-Tec Corp 26 AND OTHER 52,53 Paia Electronics 99,100 GOOD STUFF! 21 Panasonic 81 SMASHING ALL SALES RECORDS - OUR NEW 49 Panavise 105 TV Free Information Number Page 30 CHANNEL CABLE CONVERTER' 19 N.A. Philips 45 Converts mid & super 55 90 Poly Paks 123 band channels 95 AMC Sales 82 tor vie w neg on your 36 AP Products, Inc 102 22 Priority One Electronics 7 TV set, I .4 N. 3490E047 3 Aaron Gavin 26 27 Protecto Enterprises 87 5 Abex 92 58 Quietrole 104 HOT NEW IMPORT! REMOTE CONTROL 30 CHANNEL CABLE TV CONVERTER! 70 Active Electronics 109 - RCA 36 10,11 Advance Analog 92 92 R.D. Unlimited 93 95 Includes remote TV !oft switch end Advance 66 Radio Shack Ill e /5 fine tuning control, Electronics 13,24-25,42,44,47,86 69 Ramsey Electronics 115 4.95 No. 349V0275 8 ea /10 75 All Electronics 122 84 SCR Electronics, Inc. 130 ETCOMKII WIRELESS - 34 Antenna Specialists 85 2 SMP, Inc. 92 THE ULTIMATE CABLE TV CONVERTER, 78 Arizona Electronics 118 86 SRJ International 122 Set TV to channel 3 - B.G. Micro 123 13 SRS 93 he handhd 26 B&K Precision Dynascan Corp. Sabadia Exports 110 IIBIaiM:;i- oiec ....48 - '' 'No: 3492A0011 83 Babylon Electronics 127 46,47 H.W. Sams 97.105 Bagnall Electronics 126 - Satellite TV 108 VIDCOR 2000 CONVERTER ELIMINATES PROBLEMS WHEN VIDEOTAPING FROM CABLE TV Karel Barta 108 - Sencore 28-31 risslores your VCRs cape 33 Beckman Instruments CIV -,17 Shure Bros. 14-15 oeprprogramming. Re- 95 store channelinn ann VIDCOR 28 Blonder Tongue 1 - Simple Simon Electronics 46 Enables adeovmr5 2000 of one table orogrem Bullet Electronics 116 - Sinewaze Mktg. Corp 127 while watching another d 'PONS, cgweKrsa G 62 Burton Products 96 74 Sintec Co. 110 8 No. 349V09611 UNUSUAL FACTORY SURPLUS CIE, Cleveland Institute of 72 Solid State Sales 112 TV TUNER MID -BAND - SUPER -BAND CABLE Electronics 18-21 44 Soltec 104 Converts cable channels toa common IF frequency. Experi- 95 40 Cambridge Learning 96 - Spacecoast Research 108 menters - build cable convert 76 118 Suntronics Co., Inc. 114 s. decoders, etc. With Chaney Electronics - a. ! 10 schematic. No. 348VÁ342 37 Channellock 82 68 Surplus Electronics 119 1349V4,369. Derailed schematic & spec sheet 61.501 - Clear -Vue Electronics 112 93 Symmetric Sound Systems 93 FACTORY SURPLUS UHF TUNERS - Command Productions 116 - Tektronix 27 2 Testek 127 Brand new production surplus 32 Communications Electronics -

495 - All solid state. Ideal for weer - Components Express 33 30,31 Triplett Corp. CI1 work building, cable TV 53.95 mental 4 93 converters, . No. 34900099 80 Computer Peripherals Unlimited ...127 Ungar 73 Concord Electronics 114 35 Vaco 90 MINIATURE FM WIRELESS MICROPHONE - Cook's Institute 116 42 Vector Electronics Co. 32 57 Jan Crystal 10I - Wersi Electronics 110 okl he palm of your 12 Dacor Limited 93 t ands Reception on any standard FM radio or receiver. - Dage Scientific 110 No. 349VÁ482 - Data Services Co. 126 67 Digi Key Corp. 117 SCR QUARTER-MILE WIRELESS MICROPHONE 50,51 RL Drake Company 90.100 SUPER -BUYS & RECEIVER SYSTEM 8 Electro Industries 93 S FCC approved crystal controller, UHF -VHF CONVERSION KIT. wireless mikee& receiver. All 88 Electronic Specialists, Inc. 123 éeWire operated. Complete with PC board, all required com- Our 5 response VU meter Electronic Technology Today 126 No. ponents: cabinet with speaker: and compre- Own 349.4093 - ,79 Etco Electronics 116.130 Famous hensive brochure Incl. schematic, board lay- 54 Etronix 98 Klt FACTORY SURPLUS VHF i UHF out mounting and hoot -up diagrams, parts "TWIN" VARACTOR TUNERS, - Fair Radio Sales 114 IM and assembly and set-up Instructions. $119.00 AdmirdT1 . NC 24 Fluke Mfg. Co., Inc. 5 ARAN° EWl Ideal tar bu.Idm!I NI parts are Industrial prime quality.

NOnrwlly 9 rt FRONT caned - Fordham Radio 34-35.37 TV "FRONT ENDS" A naia rn NEW ZENITH ZVM121 HIGH ime loam at e sensational n.... 64 Formula International 124-125 Our Na LEGIBILITY CRT MONITOR. Features 12" preen 349vc306 18 Fox 83 Factory 16. phosphor CRT, wiTh 15 MHz Bandwidth. 40 Direct DUMPING! NORELCO ENDLESS LOOP CASSETTES' 59,60 Gladstone Electronics 101 or 80 character widths are operator switch - Price 29 Global Specialties Corp. 95 95 mpoasible to find at any selectable. Fully compatible with 80 -column price! 108 $117.00 - Global TV Electronics Apple cords, sic. 3 minutes - No 349VÁ605 6 minutes No 77 Godbout Electronics 126 - , 54 10 349..606 EN MITSUMI - MODEL UES-A55F 20 Gould, Inc. 89 VARACTOR UHF TUNER IN STOCK - THE MURA - Grantham College Of Engineering 98 FRED RANGE CORDLESS TELEPHONE SYSTEM! 470. 889 MHz $25.00 90 - Grove Enterprises, Inc 110 ANTENNA INPUT 10 for $220.03 91 Hal-Tronix 122 300 OHMS 38 Hameg, Inc. 99 -,-,14 Heath CII1,23,73-75 No. 349,4274 48 Hickok Electrical Instruments 98 SALE OF QUARTZ BATTERY 85 Hitech Electronics 118 OPERATED CLOCK MOVEMENTS! yearns 3 Huntron Instruments 92 SPECIAL on l dike 122 2200 MFD 40 VT CAP-9- 10 tat $13.50 d Imported bon, 87 Information Unlimited :.95 Flo/ e,mcarlr.No. 349VÁ561 61 International Crystal 86 5 349VA565 Matching ban*. 52.49/set. I.C. SPECIAL LM 565 to tor $16.ao 9 S1.95/set/5 65 JDR, Microdevices 128-129 J&W Electronics 114 20 AMP REGULATED 12VDC POWER SUPPLY! - H.D. TRANSISTORS 63 Electronics 120-121 Jameco SPECIALS 2 N 3055 lorar$10. 'pad_ Easily 71 113 handles ham staeo JimPak 2SA 745 manne radio. SSO lineors $4.00 an 7 Lakeside Industries 92 400, P E P Brand revv,factor, 2SA 747B $4.50 ea. sealed 110 VAC No. 349VÁ3, 94 ea' 6 Lour Sales 93 2S C 11188 $3.25 ea. 10 amps -554.95. 549.95 ea./5. I 349VA395-es above, , 114 ea - McGee's Radio 2SC 1403B $3.00 9 Masco Electronics 93 OUR LATEST 98 PAGE OUTSIDE CAL. 800-854-8660 FASCINATING CATALOG - Marsailes Horan 110 lampacked with unique items, INSIDE CAL (714) 527-2554 eleclrond bargeil, and unusual - Microtenna Associates 110 niters Write or circle tM info, or (213) 803-9385 23 Midex 43 - Monarchy Engineering, Inc. 116 SCR ELECTRONICS INC. ETCO ELECTRONICS 89 Mountain West 122 VISIT OUR NEW SUPER CENTER NORTH COUNTRY SHOPPING CENTER M 5303 Lincoln Ave., CA. I L7©0 PLATTSBURGH. N.Y. 12901 - NRI Schools 8-11 Cypress, 90630 Pay by CHECK MO, VISA M/C 11,esk odis order, please Von & Mastercard OK. (Sorry. no C.O.D.'s. Add 15% - NTS Schools 38-41 nrUPS [:Handling (Eames refunded!. N State residents add 7.4 sales sea. S10.00 MIN. ORDER HA$DUNG/SHIPPING...S2.50 Jedler & deport invited Our telephone order desk never close,. Nabih's, Inc. 104 roqulha, - UPS »W HERE N! CONTINENTN. U.S. Cal, 1 518 561 8700. - Nemal Electronics 118 CIRCLE 79 ON FREE INFORMATION CARD CIRCLE 84 ON FREE INFORMATION CARD

www.americanradiohistory.com HEATH/ZENITH &YOU, INC. ONE STRONG PARTNERSHIP

A computer purchase is the beginning of a long-term partner- OPERATING SYSTEMS - Three versatile systems give you ship between you and the people you buy from. Your ongoing the capability to perform your specific tasks. CP/M by Digital need for software, peripherals and accessories requires a Research makes your system compatible with thousands of partner who will stand by you with a growing line of products popular CP/M programs. UCSD P-System with Pascal is a to meet your needs. Heath/Zenith will be that strong partner complete program development and execution environment. for you. Look what we have to offer. HDOS, Heath Disk Operating System gives you a sophisticated flexible environment for program construction, storage, THE ALL -IN -ONE COMPUTER -The heart of the Heath/ and editing. Zenith line is the stand-alone 89 Computer. It's a complete system with built-in 5.25 -inch floppy disk drive, professional DISK SYSTEMS -The new Heath! keyboard and keypad, smart video terminal, two Z-80 micro- Zenith 67 Winchester Disk System, processors and three RS -232C Serial I/O Ports. It comes for commercial use, adds nearly with 48K bytes of RAM, expandable to 64K. 11 megabytes of storage to your 89 computer. It includes an 8 -inch PERIPHERALS AND ACCESSORIES - These include the floppy disk drive for data portability. The popular Heath/Zenith 19 Smart Video new 5.25 -inch 37 disk system, available Terminal, loaded with professional features. with 1 or 2 drives, adds up to 1.28 mega- We also offer color and black and white bytes of storage. Both plug-in systems monitors, modems, computer lan- have write protection. guage courses, and high-speed typewriter -quality, SERVICE AND SUPPORT- Prompt and professional serv- printers. ice and assistance is available nationally through Heathkit Electronics Centers, Zenith Data Systems for commercial SOFTWARE - New software, in- users or through Heath factory servicing and phone-in tech- cludes the SuperCalc Spread- nical assistance. sheet and Condor Data Base Complete, integrated computer hardware and software, de- Management System. Word processing, including signed to serve and grow with you - that's what to look for in three different programs. Small Business Programs, feature a strong partner. And with Heath/Zenith you get it all. Peachtree's Series 5, Softstuff's General Ledger and Inven- tory HUG, Heath Users' Group, offers members a Control. Heath/Zenith computer products are library of over 500 low-cost programs for home, work or play. sold nationwide through Heathkit white PROGRAMMING LANGUAGES- Electronic Centers (check your For a FREE For your own custom programs, pages for locations). mail service, write: Microsoft languages are available in catalog and order Heath Co., Dept. 020-894, BASIC (compiler and interpreter), MI 49022. FORTRAN and COBOL. Benton Harbor, APPLICATIONS SOFTWARE - Expand the performance HEATH/ZENITH range of your computer with a broad selection of software, including the best of Digital Research and Micropro - as well as the complete line of SoftstuffTM products. Your strong partner

Product specifications are subject to change without notice. 'Heathkit Electronic Centers are operated by Veritechnology Electronics Corporation, a wholly -owned subsidiary of Zenith Radio Corporation.

www.americanradiohistory.com Ops

Now there's a ination, and packed with overload More meter for hand-held DMM roofprotection. You won't find a more the money rugged tough enough to withstand acciden- meter inside or out. For starters you get 2000 hours tal drops, destructive environments, Drop -proof of continuous use off a common 9V and input overloads -and still give Constructed of double -thick transistor battery. You can run you superior Beckman performance. thermoplastics, the HD -100 resists in -circuit diode tests and check con- The HD -100 from Beckman damage even after repeated falls. tinuity. You even get a one year is drop -proof, sealed against contam- All components are heavy duty and warranty. shock mounted. The 0.25% basic volt dc accu- Water- and racy HD -100 serves you with 7 func- contamination -proof tions and 29 ranges. With one simple The HD -100 is designed to keep turn of the single select& switch, working even around dirt, heavy you can go directly to the function and grime and moisture. range you need. There's less chance The special o -ring seals, of error. ultrasonically-welded display window Feature for feature you can't and sealed input jacks protect the find a more dependable meter priced internal electronics of the HD 100 at just $169 (U.S. only). from any source of contamination. To locate your nearest distrib- The HD -100 is sealed so tightly, it's utor write Beckman Instruments, Inc., even waterproof. Instrumentation Products, 2500 Accidental overload Harbor Boulevard, Fullerton, CA protection 92634 or call (714) 993-8803. All voltage inputs are protected up to 1500 Vdc or 1000 Vrms. Cur- rent ranges are protected to 2A/250V with resistance ranges protected to 600 Vdc. Transient protection extends up to 6KV for 10 micro- seconds. BECKMAN

CIRCLE 33 ON FREE INFORMATION CARD