Radio- Electroñic1s F O R M E N W I T H I D E a S I N ELECTRONICS

Radio- Electroñic1s F O R M E N W I T H I D E A S I N ELECTRONICS

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BUILD Multipurpose IC Digital Clock Customize to fit your needs Timer -alarm you set to the minute Stop watch Interval timer 12 or 24 hours

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VARIABLE BALANCE STEREO Outstanding performance on music HEAD PHONE and speech for the price. Low im- EXPERIMENTER'S CIRCUIT HOBBYIST'S SOLDERING AND pedance matches late model BOARD KIT Unique "Sound Level" control TOOL KIT solid on state recorders. Removable desk Contains a 33/4" x each earpiece permits adjustment. Diagonals, 4" perforated long nose pliers, solder- stand; 41/2' cord with dual plugs Frequency range: 20 to 20,000 board. 15 terminals (No. 14636) + ing iron and solder. solder aid tool, that fit most models. Freq. Re- and 4 mounting feet w /screws. cps. 61/2' cord with stereo plug. heat -sink, and screwdriver. An ideal sponse: I00 8k Hz. Output: 77 Build small Impedance 4 to 16 ohms. gift item. - circuits, hobby and dB Impedance 200 ohms science projects, etc. Cat. No. Q4-132 $17.95 Net Cat. No. H3.378 $7.95 Net. Cat. No. Q4 -146 $4.95 Net Cat. No. 14 -660 $.98 Net

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Grantham School of Engineering NE -6 -70 Three Big Steps 1505 N. Western Ave., Hollywood, Calif. 90027 Gentlemen: to Success... Please mail me your free Bulletin which explains how the Grantham educational program can prepare me for my FCC in license and Associate Degree in Electronics Engineering. I understand no salesman or counselor will call. Name ELECTRONICS Address City State Zip ENGINEERING I have been in electronics for years. L J There they are - three big steps that lead electronics technicians to greater success - three deliberate steps to greater recognition and more income. Your future is shaped by the moves you make - by the steps you take. Begin now with Step #1. 10:411111+:4111163K4MINIRKOIIIERKWtiIAKII STEP *1 is a simple request for full information on the iìaiyctm,tr`.tlrriíi. Grantham Electronics Degree Program. You take this first rEntsfLtt.ewffnr. 'HA-r.10. afnatrftito. coupon. Then, we mail aiMfuativón:stJtittiteNoJlw[oolim step by filling out and mailing the itsfojfo rlw.rirs.. our catalog to you; we do not send a salesman. STEP #2 is passing the examination for your first class FCC license. It is certainly true that an FCC license is important - sometimes essential - but it's not enough! Without fur- ill, ther education, you can't make it to the top. Get your FCC license without fail, but don't stop there. To prepare for the : _ best jobs, continue your electronics education and get your degree. STEP *3 is earning your Associate in Science Degree in j Electronics Engineering (the ASEE). If you have completed ...... 4e.,a-ä+Er:_s1M:é T-:ß3Z."ts rZi:Lf+,. at least one year of fulltime experience as a bona fide electronics technician, you may earn your ASEE Degree almost entirely by correspondence - including a minimum resident attendance of only two weeks. Accreditation, and G.I. Bill Approval by the Ac- Scijoot of engineering Grantham School of Engineering is accredited @rantfjam crediting Commission of the National Home Study Council, ryas toilful-to on is approved under the G.I. Bill, and is authorized under the laws of the State of California to grant academic degrees. joint pot Home Method thr orgrtc of The -Study

7lggoúatt in eitntt in electronicg tangineeríng Grantham School of Engineering is a specialized, college - level, educational institution - established in 1951 -which !hereunto In mmne.s Wrest INS sp... mnh all Ito rights ..e .rmecae. .awrmmna by the so- called "new approach." This eui. faure ent wen mure Or m, mwi ae.mrr.i,nn uc. n re..mmenruol r rk teaches engineering is the method (often referred to by names such as "inde- WWI? III TIN .b.M km. M/~'.1_i'. ' pendent study ") that has recently created great interest among college educators. Actually, this "new approach" is / .refkN new at all. Grantham and many other good schools have M11/rM-,.,4-1 not been using it for years, under such names as "home study" and "correspondence instruction." As a technician, you already know the "hardware" side of CRANTHAMENGINEERING electronics, and you can upgrade from technician to engi- "the college that comes to you" neer while you continue your employment as a technician. 1505 N. Western Av, Hollywood, CA 90027 Get complete details. Mail the coupon for our free bulletin. Grantham is an Accredited Member of the National Home Study Council.

ItCircle 1 on reader service card Circle 2 on reader service card NEW &TIMELY Volume 41 Number 8 RADIO -ELECTRONICS August 1970

AIRBORNE COMPUTER TO GUIDE SHUTTLE JETS DIODES USED IN HIGH -DENSITY IC MEMORY BOSTON LOGAN MURRAY HILL, N. .l.- rogation pulses. Bell predicts The tiny memory cell shown read speed rates to 50 bil- in the scanning- electron -mi- lionths of a second. LA GUARDIA AREA NAV. i WAYPOINT is a new IC A memory capacity of A NAV. croscope photo WAYPOINREA T type under development at 100,000 bits per square inch WHITMAN MADISON Bell Labs for future tele- may be possible, according to -- -____ `` NORWICH phone systems. PROVIDENCE switching Each .003 x .005 -inch cell Area navigation vs. conventional navigation (dashed line) from New York to Boston. Below, the display chart and (left to right) auto- in the IC array is a reverse - pilot controller, distance /time display, computer control and computer. biased Schottky diode connected in series with a diffused l á' pn junction diode. A large or small charge (1 or 0) is placed on the reverse- biased diode.

;,. . Each bit must be replenished every 1/20 sec as the charge dissipates. The design is called "charge transfer diode memory" since the charge is temporarily transferred to the other diode during read and Bell. The company is looking write operations. Cells are ar- for better memory systems to navi- NEW YORK- Eastern Air- radio stations (or other ranged in an x, y structure handle the information that inputs) and contin- lines' Air -Shuttle jets oper- gation using a metal beam for "x" must be stored for telephone Bos- ually plots the posi- ating into Washington. aircraft's and a silicon bar for "y." calls. Two 10 -digit phone a chart. Pilots ton and New York -area tion on moving Readout is accomplished by numbers (for the called and see hearing to airports this fall will use a can range and detecting the charge stored in calling subscribers) require at computerized navigation sys- points along the route by se- a cell by sensing the foward least temporary storage of tem to fly shorter, less con- lecting the geographical posi- charge flow through the x, y some 80 binary digits. tion on the computer control gested routes. leads in response to inter- (N & T continued on page 6) Pilots will not have to 12 -key turret switch. Each thread their way from one digital key defines preselected navigational radio station to points. The autopilot control the next. Traffic now must unit couples the computer - slow down when aircraft on based navigation signals into the same or intersecting the aircraft's autopilot. routes overfly radio stations. Eastern is buying the sys- The system, called Omni - tem from Decca Navigator trac, uses a 4096 -word, 50- Co.. a British firm. byte digital computer that accepts radio signals from FAA APOLLO 13 OVERLOAD HOUSTON -An overload of voltage applied to two heater switches in an Apollo 13 oxy- gen tank apparently caused the explosion aboard the spacecraft. The overload occurred during an attempt to drain the tank prior to the April 11 blastoff. Because of difficulty in draining the tank, 65 volts dc was applied to the thermostat A miniature electromechanical servo system attached to a camera in switches, which were designed a helicopter made the dramatic difference in these photos of the Jeffer- for 30 volts. This apparently son Monument in Washington, D.C. The shots were taken with a 400-mm Las Vegas -Some 300 radio -con- fused the switches, causing lens at 1/50 sec, but helicopter jiggling and vibration was sensed by trolled, scale -model aircraft will heaters to slowly bake away two tiny gyroscopes mounted in a bellow-like collar in front of the be matched in international com- camera lens. The cylindrical, fluid -filled bellows has glass discs at each wire insulation and cause a petition here September 4 -7. Race end. The bellows, therefore, is an optical element whose refraction officials predict world speed rec- short circuit. angle can be changed by bending the glass discs in response to signals ords will be broken as the R C transmitted from the gyros. Dynasciences Corp., a Los Angeles firm who models approach scale speeds of NEXT MONTH have aimed their sales at the military, movie and TV industries and 200 mph. Over $6,000 for prizes Build a computerized law enforcement agencies, is developing a less expensive version. is being offered by the Mint Hotel, IC music synthesizer. One of the image stabilizer systems is shown above mounted on a sponsor of the event. 35-mm Arriflex camera. 2 RADIO- ELECTRONICS Radio-Electronics

August 1970 Over 60 Years of Electronics Publishing Versatile IC Digital Clock offers variety of precise timing functions. Build 12- or 24 -hour version with a minute alarm. TELEVISION ... see page 46

Inside Portable Vtr's 9 G. McGinty Electronic photography in a shoulder pack

Color TV Cameras 30 , , , Walter G. Salm New designs bring the prices down

Kwik- FixTS1 Troubleshooting Charts, 33 ,Forest H. Belt Color difference amplifiers

In The Shop 64 Jack Darr Diddle adjustments for color Service Clinic 65 Jack Darr

ELECTRONIC TIMEPIECES

Electronic Watches 39 . . .Larry Steckler Ilo.r they work -including a 44 -IC wristwatch

Build: Multipurpose IC Digital Clock . 46 Leo Walker 12 or 24 hours with a timer alarm and more

Build: Superaccurate IC Digital Clock 54 .Lindsey G. Riddle Portable vtr's give you up to 1/2 -hour of l0 -\111 crystal time base "point- and -shoot" electronic photography. Find out how the latest models work. . . . see page 9 BUILD THIS ONE

Charger for Rechargeable Alkaline Batteries 52 H. R. Mallory Money -saving unit handles I to IO cells

GENERAL ELECTRONICS Looking Ahead 4 David Lachenbruch aoi ( in rent happenings with future overtones

R. 30 CA3018 IC Projects 22 . . . M. Marston Solar transistor device operates front dc to vhf -part I Color TV cameras used to carry five - figure price tags until this one -tube model hit the market. How long before under -$1,000 versions are available? DEPARTMENTS . . . see page 30

Noteworthy Circuits 70 CB Troubleshooter's Casebook 63 New & Timely 2

Service Card Coming Next Month 71 New literature 61 Reader 77 69 Correspondence 14 New Products 56 Try This One

ItAI)1O- ELEC'TRONIC'S. AUGUST 1074 Vol. 41. No. Radio -Electronics is indexed in Published monthly by Gernsback Publications. Inc., at Ferry St.. Concord. N. H. 03302 ^ó Applied Science & Technology and Executlre offices: 200 lark Ace. S.. New York. N.Y. 10003. Subscription Servies: Boulder, Colo. 80302. Editorial. Advertising, Index (formerly Industrial Second -class postage paid at Concord. N. il. Printed In C.S.A. One-year subscription rate: C.S. and possessions. Canada. $1. á reserved. os Pan- American countries. 27. Other countrie . 27.511. Single copies 60e. (t) 1070 by Gernsback Publications, Inc. All rights eaA Arts Index) POSTMASTER: Notices of undellcered copies (Form 3579) to Boulder. Colo. 80302 . LOOKING AHEAD Volume 41 Number 8 RADIO -ELECTRONICS August 1970

by DAVID LACHENBRUCH ner as standard vhf tuners now on the market. CONTRIBUTING EDITOR Philco -Ford attacks the problem of difficult uhf tuning with an electronic uhf tuner combined with mechanical The new color sets vhf tuning in two of its models. The new tuner may be preset to any six uhf channels, using buttons which merely As promised, the 1971 model year will be a year of have to be touched (not pushed) to tune the channels in more- than -usual innovation in U.S. -manufactured color any sequence. Philco also introduced a six -detent mechani- TV. Though nothing startlingly new has appeared yet, al- cal uhf tuner, as did RCA. most every television set manufacturer has adopted several advanced concepts in an attempt to get consumers back into the TV- buying mood. Toward automatic color Although not all TV set lines had been previewed at No -hands color control is obviously the goal of set our press time, it is now clear that several major trends are manufacturers, and most of them are using some form of sweeping the industry, including: (1) The new super -rec- flesh -tone corrector in combination with AFC and auto- tangular picture tube sizes. (2) All- electronic varactor tun- matic chroma control. Last year the flesh -tone corrector ing. (3) Flesh -tone correction systems (such as Magna- was a selling point for Philco -Ford and Magnavox. This vox's TAC) under a variety of proprietary names. (4) year, Zenith has its similar "Automatic Tint Guard," Ad- Heavier use of solid -state devices, including more all- solid- miral its "Color Monitor," RCA its "Accu- Color," and so state chassis. forth. Japanese manufacturers appear to be approaching the question in a different manner, through preset controls. Those new picture tubes Hitachi, for example, has a feature called "Automatic Pic- ture Setting." Color, tint, brightness and contrast are preset cornered tubes, measuring 19, 21 and The new square- at the factory (and can be reset by the service technician) viewable have an aspect ratio of 4- 25 inches in diagonal, for optimum picture. The viewer may override the factory as transmitted image. Their surface is by-3, the same the settings and adjust the picture manually. they present a more pleasing picture. Two flatter and Another new circuit has been added by Philco -Ford North American manufacturers have introduced lines us- to its "Cosmetic Color" tint adjustor. This is called "Auto- ing all three new sizes -Electrohome of Canada and Mag- matic Color Balance," which is controlled by the color Zenith is using both the 19- and the 25 -inch, and navox. burst signal and monitors the green -to -blue ratio. When a most of the others have the 25 -inch only but plan to in- color signal is being received, it automatically adds empha- the other sizes later. troduce sis to the green portion of the signal, eliminating bluish has made the most extensive switchover, Magnavox tinges to solid -green areas, such as football fields. almost completely replacing its 18- and 20 -inch models black-and -white signal is being received, the circuit steps 21 -inch sets and featuring 46 of the new 25- with 19- and the blue to avoid a sepia tone on the picture. inch sets as compared to only nine with 23 -inch screens. In most lines the 25 -inch tube takes over in the top -of-the -line area, replacing all 23 -inch models beginning in the area of Solid -state developments $600 to $700 list price. At least three new all- solid -state chassis will appear in The various black- matrix or black -surround phosphor the 1971 color models. Zenith hasn't yet announced details, techniques are becoming more widespread, particularly in but it will have one making extensive use of its "Dura- the 25 -inch tube. In addition to Admiral, RCA and Zenith, Module" connecting system and more advanced IC's. Zen- Sylvania has now added its own "black composite" system. ith's 19 -inch chassis is a new hybrid with only four tubes. It has four ICs and uses a solid -state, high -voltage tripler Electronic tuning rectifier system. Sylvania, which uses tripler rectifiers in most sets, em- begin ship- Sylvania is the first U.S. manufacturer to ploys its first all- solid -state chassis in its high -end 25 -inch ping sets with all- electronic varactor tuning for all chan- sets. It has four i.f. stages and uses plug -in transistors for system, nels, but others will follow closely. The Sylvania easy replacement. RCA has redesigned its solid-state uses 11 currently using many German -made components, chassis, which it now features in sets starting at $649.95; it vertically grouped pushbuttons, each of which can be pre- slides from the rear of the set for servicing. set to any vhf or uhf channel -in effect II individual all - channel tuners. Pushing any button immediately brings the corresponding channel into view -the tuner doesn't run New warranty war? successively through intermediate channels. Each set is Most TV manufacturer warranty plans seem to satisfy shipped with 82 die -cut channel indicators. When the tuner no one. RCA's new Purchaser Satisfaction (PS) policy for is set up for local conditions (generally by the dealer), the its 1971 lines is designed to make everyone happy, including proper channel numbers are inserted into a transparent both the consumer and the service technician. It extends sleeve alongside the pushbutton bank. Sylvania's elec- the guarantee on 23- and 25 -inch solid -state color sets to tronically -tuned sets, with 25 -inch tube and solid -state one full year's labor, providing 90 days' labor on all other chassis, will start at a suggested list of $725. products. The intriguing aspect of the plan is that it gives Zenith promised late summer delivery of its own va- the set owner freedom of choice in selecting his repair ractor -tuned set. This one uses a pushbar to bring in up to agency. The service dealer performing the work submits 14 vhf and uhf channels in any prearranged sequence, for this bill, at the regular rates, to any of 21 district warranty tuning either at the set or remotely. In other models, Zen- offices for payment. (Portable radios, phonos and record- ith also continues its mechanical uhf detent tuner which ers, which have a 90 -day, over -the -counter exchange war- clicks any six uhf channels into position in the same man- ranty, are excepted.) R -E 4 RADIO -ELECTRONICS INSTANT LOADING TAPE CARTRIDGE

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Just what you've been waiting for. The new Mallory They'll fit any cassette recorder, player, cassette - DURATAPE ' Cassette. radio. Even the new cassette changers. And you pick the You get the quality and performance of expensive tape recording time: 30, 60, 90, 120 minutes. cassettes at a nice, lots -less price. But not the poor Our DURATAPE ' Cassettes are tough but we put them performance or the problems of the special- discount in unbreakable, easy -to -stack containers just for extra cheapies. protection. Like in the rain or through the mail. And since they're from Mallory - a company long And we make a head cleaner that's perfect for Cassette known for quality electronic products -you can expect Recorders, too. high fidelity, smooth operation, and long reliability. And You'll find this great new thing in sound wherever get it ... every time! Mallory products are sold.

MALLORY DISTRIBUTOR PRODUCTS COMPANY MALLORY a division of P. R. MALLORY & CO. INC. Box 1668. Indianapolis. Indiana 40208; Telephone: 317.030.6363

Batteries Capacitors Cassette Tapes Controls Resistors Semiconductors Sonalert Switches Timers Vibrators ICs Circle 3 on reader Aerricc card AUGUST 1970 5 (Continued from page 2) New &Timely

battery- operated, 10 -watt sys- SYSTEM CONVERTS TEXT TO SYNTHETIC SPEECH tem will permit astronauts to communicate with earth - model vocal tract as the com- based stations without the sig- puter "reads" the passage. nals being relayed through Applications? Bell says the the Lunar Module. An um- system may someday be use- brella -like, 38 -inch diameter ful for automatic information antenna will eliminate the services with extensive vocab- need for one astronaut to re ularies. Doctors could have a main within sight of the LM. page recited from a medical The antenna can quickly be textbook, or a stock manager deployed as the astronauts could get information on a explore the lunar surface. company inventory. An aid for The system will be de- the blind and programmed in- MURRAY HILL, N. signed to be mounted on the J.- struction are other possibilities. "Hands- Free" phone, one of some Speech researchers and engi- Lunar Rover vehicle, slated 100 being installed in New York for use on Apollo 16. In ad- City, is put to use at Grand Cen- neers at Bell Labs have de- TRANSMITTER TO AID vised a computerized system dition to providing TV view- tral Station. A recessed micro- APOLLO EXPLORATION phone, protected by a grille, is for printed text into ers with scenes of the lunar converting used for speaking, while a loud- synthetic speech. The text -to- NEW YORK -A briefcase - exploration, the system may speaker in the ceiling of the booth talk conversion includes a sized transmitter /receiver is be used to send a colorcast of lets you hear the party you've computerized approximation being developed by RCA for the LM's blastoff from the called. A volume control s provided for the loudspeaker. rules of timing, use on the lunar surface. The moon's surface. The of the complex hand -free phone trial is an at- pitch and stress people use in tempt to eliminate vandalism. everyday conversation. sent to the com- A passage CARTRIDGE COLOR TV puter via a teletypewriter has timing and stress assigned to A home cartridge color each word by the computer, TV system for under $900 which then finds a phonetic will be marketed by Cart- description of each word from ridge Television Inc., an a dictionary stored in the com- Avco Corp. subsidiary. puter memory. Also stored The unit consists of a are mathematical approxima- cartridge video tape deck com- tions for the shapes and mo- bined with a color TV re- tions the human vocal tract Automated health screening system rapidly collects and records medical ceiver. Blank tapes will cost data while you recline in a special contour chair. Introduced recently by $8 for 30 mins. - makes. Mathematical descrip- the Chicago -based International Health Systems, the new Computa -Lab under Full tions of vocal -tract motions is designed to accurately measure basic parameters of the human body length movies for rental at $3 are computed and used to at low costs. Mobility for the module was achieved by using smaller are planned. (Avco owns Em- generate electrical speech sig- medical test components that are linked to a sequential switching bassy Pictures.) mechanism. A technician can screen two persons in 30 minutes, ob- oscilloscope displays Avco is reportedly ready- nals. An taining, with other data, a record of sight, pulmonary function, respira- the changes that occur in a tion, a phonocardiogram, electrocardiogram and electrocardioanalysis. ing a California plant. -R -E

RADIO -ELECTRONICS is published SUBSCRIPTION SERVICE: Send all subscription orders by Gernsback Publications, Inc. and correspondence to RADIO- ELECTRONICS, Subscrip- Radio -Electronics 200 Park Ave. South tion Department, Boulder, Colo. 80302. New York, N.Y. 10003 MOVING? For change of address, allow six weeks, fur- HUGO GERNSBACK (1884 -1967) (212) 777 -6400 nishing both the old and new addresses and if possible founder President: M. Harvey Gernsback attaching label from a recent issue below. Otherwise Secretary: Bet lina Baer please print clearly your name and address exactly as it appears on your label. M. HARVEY GERNSBACK, ADVERTISING SALES editor and publisher EAST 1- John J. Lamson, Eastern Sales Mgr. LARRY STECKLER, managing editor N.Y.C. (212) 777 -6400 MID WEST/Texas/Arkansas /Okla. Robert F. Scott, W2PWG senior technical editor Ralph Bergen, ATTACH LABEL HERE 6319 N. Central Ave. John R. Free, associate editor Chicago, Ill. 60646 (312) 792 -3646 lack Darr, service editor PACIFIC COAST/Mountain States I. Queen, editorial associate I. E. Publishers Representative Co., L Matthew Mandl, contributing editor 8560 Sunset Blvd., Suite 601 Los Angeles, Calif. 90069 David Lachenbruch, contributing editor 1213) 659 -3810 name (please print) 420 Market St. San Francisco, Calif. Vincent P. Cicenia, production manager 94111, (415) 981 -4527 address Barbara Rosefelt, production assistant SOUTHEAST E. Lucian Neff Associates circulation city state zip code H. Matysko, 25 Castle Harbor Isle Fort Lauderdale, Florida 33308 Mail to: RADIO -ELECTRONICS Cover by Harry Schlack (305) 566-5656 SUBSCRIPTION DEPT., BOULDER. COLO. 80302 6 RADIO- ELECTRONICS Now a Heathkit® Solid State Vectorscope /Color Generator Only $124.95* idlIZZEZEIS RITENSITI

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Accurately Performs All Of These Adjustments: 3.58 MHz Oscillator Raster Reactance Coil Static & Dynamic Convergence Phase Detector Transformer Purity Demodulator Angle Check Gray Scale Chroma Bandpass Touch -Up Kit 10 -101, 12 lbs. $124.95'

Fast switch selection of standard 9 x 9 display ... or exclusive Heath "3 x 3" display

J Color Dt Horizontal 3x3 3x3 3x3 /j Bars Ì P.rttrrn Bars Color Bars Clot Horizontal - -_ l Ì Shading Cross Vertical e a 3x3 3x3 3x3 Bars Hatch Bars R Shading Cross Hatch Vertical / C R --

10 -101 SPECIFICATIONS - PATTERNS - Purity: Produces o snow -free raster for purity adjustments. Dots': 9 x 9 produces a display of 110 small dots. 3 x 3 produces a display of nine HEATH COMPANY, Dept. 20 -5 dots for convergence a Schlumberger company adjustments. Crosshatch: 9 x 9 produces a display of 11 vertical and 10 Benton Harbor, Michigan 49022 horizontal lines. 3 x 3 produces a display of three vertical and three horizontal lines for con. vergence and linearity adjustments. Horizontal Lines': 9 x 9 produces a display of 10 horizontal L] Please send FREE Heathkit Catalog lines 3 x 3 produces a three display of horizontal lines for vertical linearity and pin -cushion Please send 10 -101 Specilication Sheet adjustments. Vertical Lines': 9 x 9 produces 11 vertical lines. 3 x 3 produces a display of 3 vertical lines for horizontal linearity and convergence adjustments. Color Sore: 9 x 9 produces a display Enclosed is $ plus shipping. of ten standard color bars. 3 x 3 produces a display of three standard color bars. A visual finger. Please send Model 10 -101 print (voltage pattern) of all ten color bars in the form of a petal pattern is displayed for color circuit servicing. Gray Scat*: Provides a wide bar crosshatch pattern with six shades of bright ness for color gun level adjustments. OUTPUT SIGNALS - Video: Greater than t1 volt peak - Name topeak composite signal for composite signal injection beyond the video detector. RF: Variable to approximately 25,000 uV output, channels 2 through 6, for composite signal injection into the Address TV receiver antenna input terminals. Sync: Greater than 3.5 volts peak -to -peak signal for servicing sync circuits without video, or sets having separate video and sync demodulator phase adjust. City State Zip ments. GENERAL - Power Requirements: 105 -125 or 210-250 VAC, 50/60 Hz, 20 Walls. Cabinet Dimensions: W x x 6?j' 9t.i' H 14' 2. D. Net Weight: 9,1 z lbs. Prices and specifications subject to change without notice. The number of dols, lines, and bars indicated for a 9 x 9 display is the number displayed if the =Mail Order Prices; F.O.B. Factory TE -222R receiver under test has no overscan. J Circle 4 ori reculer service card AUGUST 1970 7 Shortstop. 111

AsOkt 411, Our exclusive posted -filament design stops shorts in high- voltage rectifiers. And you know what shorts cause ... catastrophic failure, or weak- ened tubes and components. The result: unprofitable callbacks. Our 3CU3A, 3BM2A, 3BL2A, and 3DC3 high-voltage rectifiers all use the fail -safe posted -filament design. Put our shortstops on your team. You'll find that callbacks won't even get to first base. Sylvania Electronic Components, Electronic Tube Division, West Third St., Emporium, Pa. 15834. SYLVAN IA GENERAL TELEPHONE & ELECTRONICS

8 RADIO- ELECTRONICS ELECTRONIC PHOTOGRAPHY BECAME A REALITY A FEW years ago when some inventive engineering freed helical - Inside scan video tape recorders from their ties to the power line. These portables give nearly all the freedom of hand -held movie cameras with such extras as fully automatic audio recording, 20- minute (and now 1/2-hour) recording time, Portable fully automatic "point- and-shoot" operation, and no waiting for processing. The latest versions, now hitting the market, have such added features as powered rewind, fast -forward and playback with the picture appearing in the viewfinder. One portable now on the market is the Sony DVK- 2400. The shoulder pack contains the 1/2 -inch helical -scan vtr powered by sealed lead -acid storage batteries that provide a VTR's running time of about 1 hour. The tapes last 20 minutes, so there is plenty of energy for setting up operations and making two tapes. The deck contains the tape transport, automatic -video and audio- record circuits, the servo system that drives tht tape transport and the scanner (which contains the rotating video heads). The camera uses a small (% -inch) separate -mesh vidicon and is equipped with a 4 -to -1 zoom lens as standard equipment. It operates like a fully automatic "through- the -lens" camera, since the viewfinder is actually a 1 -inch TV screen that displays the video being sent down the connection cable to the recorder (see photo). Record- ings are started by pulling the trigger on the hand grip. Some operating signals to the camera man are: a red light in the eyepiece to show when recordings are in prog- ress (tape moving): low battery -voltage alarm (the viewfinder's raster goes out of focus) and tape run -out alarm (the viewfinder's raster goes out). The captive -camera idea In most video tape recorders the servo system times the rotating video heads in the scanner to start their swipe across the tape in synchronism with the start of a vertical field. The idea is to get the heads at the right place at the right time. To do this, the vtr locks on vertical sync pulses that are part of the incoming signal. These vtr's make use of the 60 -Hz power line to drive the tape transport at the right speed and to get the scanner (rotating heads) in the right ball park in terms of rotating speed. The servo system in the portables is much simpler. It simply makes the scanner rotate at the right speed and pays no attention to input signals. However, the scanner generates sync signals to drive the camera. In this way, when the rotating video heads come into position to start a swipe across the tape, a sync pulse is sent to the camera and the camera starts a vertical field. The term "captive camera" is used to describe this mode of operation. Its advantage is that the servo system in the vtr becomes a very simple speed regulator and nothing more. The basic concept of the speed -regulating servos used in helical -scan vtr's is in Fig. 1. A dc motor drives the scanner directly. The scanner contains the rotating video - head assembly. Most portables are two -head machines. Here each head is in contact with the tape for half a revo- by G. McGINTY lution. Since the head must traverse the tape in the time taken for one vertical field (1/60 sec), half a revolution takes 1/60 sec and a full revolution takes 1/30 sec. Thus Portable video tape recorders pack a lot of the correct rotating speed for the scanner is 30 rps, or 1800 rpm. An iron vane on the scanner assembly cuts the sophisticated electronics into small shoulder fields of a pair of pulse coils to generate 60 -Hz sync pulses for the camera. The pulse coils are positioned so that the packs. Here's how the latest models work pulses are generated when the video heads start their swipe across the tape. A tone generator connected to one end of the motor shaft generates feedback signals for the servo system and, as a byproduct, 15,750 -Hz sync signals for the camera. The tone generator is usually an iron wheel with 525 ridges AUGUST 1970 9 milled into its edge (see detail in Fig. 1). A pole piece, through which direct current Pulse mating From Supply Coils Reel flows, generates sinusoidal signals as follows. When the SCANNER ridges on the wheel line up with the ridges on the stationary pole piece, the magnetic reluctance of the system is minimum and the coil has maximum inductance. Similarly, Slip Rings Pulse Vane To Capstan inductance is minimum when the peaks on the wheel are opposite the valleys on the pole piece. Since the wheel ro- tates at 30 rps, the 525 -tooth arrangement produces a Path of Video Record Heod 30 x 525 = 15,750 -Hz signal (when the scanner is rotat- Video Head ing at the correct speed). Speed control is achieved by comparing the output frequency of the tone generator with some sort of frequency reference. The result of this comparison is used to control the rotation of the drive motor, a dc motor with a +12VDC permanent -magnet field. The way in which the comparator at the servo sys- 15,750 Hz Output works differs between units, so let's look tems in detail. Belt Drive to Capstan Sony DV -2400 system 2 the speed -regu- DRIVE PULLEY Fig. shows the block diagram of lating servo used in the Sony DV -2400. This unit employs Derail of a reference. is the slope the high Tone Gen,a, unique speed It actually of FIG. SIMPLIFIED VIEW of video scanner assembly. A 15,750 - end of a low -pass filter. Since the filter (a bridged -T ar- 1- the Hz signal is fed from tone generator as the 525 iron ridges on rangement) uses RC components, the frequency reference wheel rotate at 30 rps near the mating pole piece. is independent of variations in battery voltage, temperature or other environmental factors. Operating characteristics are shown in Fig. 3. The straight -line characteristic is the speed -vs- frequency graph of the tone generator. It's a simple ac generator, so output frequency is directly proportional to speed. This graph is superimposed on that of the frequency -vs- output curve of the low -pass filter. When the power is switched on, a capacitor charging into the input of the armature- switching circuit applies a burst of armature current for the motor and it accelerates TV SCREEN serves rapidly. At low speeds the amplified and limited output of as viewfinder in the tone generator produces maximum output from the Sony DV C -2400. showing the picture low -pass filter. being sent to the This results in maximum drive to the armature -cur- portable vtr. (Eye- piece removed from rent control circuit and the motor continues to accelerate. camera.) As speed approaches the correct value, output from the low -pass filter begins to fall and armature current follows 60 Ho 60142 Sena suit. Pulse Ceti 10 Comma A stable operating point is reached where the tone JET_ MR generator's graph crosses that of the low -pass filter. Here

Armature an increase in speed (that might result from installing Clamp PM 5,e,lcnin0 Mctor scanner freshly charged batteries) results in less output from the Tone low -pass filter. A drop in speed (caused by increased mechanical loading when tape begins to move) causes an in- WM f L r-Pass crease in filter output and a corresponding boost in arma- Limiters Amp f nMnn oFlirr__ ture current. scanner speed is held within narrow limits Emitter In this way, Foller.er 750 142 despite variations in battery voltage and mechanical load- to Coméra S,nc ing. Tape speed is also constant as the same motor that 2 SYSTEM used in the Sony DV -2400. System's FIG. -SERVO a speed reference utilizes the slope of a low -pass RC filter. drives the scanner directly, drives the capstan through rubber belt. , Low -Pass Filter The series of limiters ahead of the low -pass filter eliminates amplitude variations so that only frequency deter- Operating Point mines the output of the low -pass filter. In addition, the 15,750 -Hz square waves are tapped out of the limiters Tone Generator through an emitter follower to provide horizontal drive for Tone Gen the camera. Output switching and Armature current is controlled by the cir- Filter Output cuit shown in Fig. 4. This system converts the varying amplitude signal at the output of the filter to a varying pulse -width armature current. Fig. 5 -a shows the output signal at the low -pass filter; Fig. 5 -b's waveform shows the increase in amplitude that results from "thumbing" the mo- Frequency 15,750 Hz tor shaft. The signal is sinusoidal because almost all har- of servo. Tone gen- FIG. 3- OPERATING CHARACTERISTICS are removed by the low -pass filter. erator output is superimposed on frequency vs output curve. monics RADIO -ELECTRONICS 10 A diode clamp ties down the negative peaks of the 12V DC D209,210.211 waveform to about 0.6 volt, and the positive excursions Clamp Motor drive Q2I0 into conduction. The duration of the con- Armature ducting pulse (conduction angle) depends upon the ampli- Filter tude of the input signal. When Q210 saturates, Q211 is cut 0.6V off. This leaves Q212 with a 470 -ohm base resistor to B +, so Q212 saturates. Thus, Q212 follows the action of Q210. Armatura Curren! C220 9V Fig. 5 -c shows the waveform at the collector of Q210. 0211 Reg. 02 0 0212 waveform Sternaa The negative-going part of the represents the Capauto. time that Q210 is saturated and thus represents the dura- FIG. 4 -THREE -STAGE SWITCH controls armature tion of the armature current pulse. Note the effect on the current. width of this pulse as the motor shaft is "thumbed" (Fig. a 5 -d). Diodes D209 -D211 absorb energy produced by the motor when it is slowing down and acting like a generator. Starting capacitor C220 charges into the base circuit of Q210 when power is first applied. This gives the motor its starting kick. Shibaden SV -707J portable The servo in the Shibaden portable uses a monostable d multivibrator with a rigidly controlled pulse width as the frequency reference. The system is shown simplified in Fig. 6. Transistors Q201 and Q202 form a monostable multi - vibrator in which Q202 is normally conducting and Q201 is cut off. This puts the collector of Q201 at about the B+ level. emmammai A pulse from the amplified output of the tone generator turns off Q202 and this turns on Q201. This condition FIG. 5 -a- LOW -PASS FILTER OUTPUT. b -Same output is is maintained until the discharge of C203 through R -201 boosted when motor is restrained. c- Waveform at collector of Q210 in Fig. 4. d- "Thumbed" motor widens the pulse width. brings Q202's base voltage up to about 0.6 volt, at which time Q202 resumes conduction. Notice that R201 is not returned to B+ as in conventional multivibrators, but is returned to a steady reference voltage maintained by Zener diode D202. Pulse width is held within narrow limits. At low speeds the collector of Q201 remains at B+ for relatively long periods, and drops to zero for the fixed conducting interval, as the top waveform in Fig. 6 shows. This waveform is filtered by an RC network and applied through a diode to one side of differential amplifier Q204 -Q203. Because the low -speed waveform is positive most of the time, the dc voltage applied to Q204 is highly positive and drives Q204 heavily into conduction. As a result of differential -amplifier action the heavy current through Q204 starves Q203 and the latter's collector voltage rises. Two cascaded emitter followers apply Q203's collector voltage to the motor armature and the motor is made to accelerate. As motor acceleration continues, multivibrator Q201 and Q202 operates at higher frequencies and the duty cycle the of waveform at the collector of Q201 changes as INSIDE SONY DVC -2400 camera showing CRT and ma;;net. shown. The result of filtering this waveform is a lower dc voltage. Thus, less current is applied to the motor armature. A stable operating point is reached where the output voltage of the filter is about equal to the dc voltage applied to the Q203 -half of the differential amplifier. Note, too, that this base voltage is developed from Zener diode D202. Speed is adjusted by varying the pulse width of the monostable multivibrator with R201. It is adjusted to ob- Lo. tain a motor speed of 30 rps with tape loaded and correct Speed nominal battery voltage. It's quite easy to check speed. A SDtea u u u ll ll scope is used to monitor the 60 -Hz sync pulse developed by Rpegn the set of pickup coils mounted on the scanner assembly, Sea'ruuuuuutl- and the scope time base is synchronized by the power line. D+ R201 is then adjusted until the pulses are stationary on the Tom 5,750H, time base. Amp. 6tntrelor Control -track recording All vtr's record a series of control -track pulses on the tape. They serve the same function as sprocket holes in movie film. During record, a control pulse is recorded on FIG. 6 -SERVO CIRCUIT in the Shibaden vtr uses monostable the tape each time one of the rotating video heads starts its multivibrator's pulse width as the frequency reference. AUGUST 1970 11 swipe across the tape. (In playback, these pulses serve to tell the scanner's servo system that the recorded video track is in the correct position for the video head to start its pass Mono Emitter 60 Hz Mullí Follower Sync to Comers across the tape.) In vtr's with two video heads, a pulse is recorded once per revolution, at the start of the pass made by one of the video heads (usually designated the A head). The scheme used in Sony's DV-2400 is shown in Fig. 7. Here a set of Audio input pulse coils, 180° apart, is mounted above the rotating plat- A 30 Ho 30 Hz 30 Hz Control Trued form that mounts above the video -head assembly. small Pulse Cod Pulse Cod Pulsee A iron vane is fastened to the beam on which the A video B position 11-1_1.....11.1.14.1,. , head is mounted. As the head sweeps around into to begin its pass across the tape, the vane cuts the field of Audio /Contol Track the pulse coil and a pulse (a single sine wave) is generated Record Head in the coil. This pulse is shaped, amplified and applied to the control -track head. Here the pulse is recorded on the lower of the tape. (This audio -record head is mounted in PULSES are recorded on lower tape edge FIG. 7- CONTROL -TRACK -track head; audio is edge in DV -2400 every time the tape head starts its pass. the sane assembly with the control recorded on the top edge of the tape.) The same pulse used Emitter is applied to a monostable Ilow HI ena for control -track recording also s+I1 -ryl and Pre - Preomp Follower Filter emphasis multivibrator. This multivibrator is also triggered by the output of the second pulse coil shown in Fig. 7. Thus the Peak Slip n9s White FM Record multivibrator is triggered twice per revolution of the scan- Mod Amp _ Record Hoods ner to generate the 60 -Hz pulses that serve as sync for the

Clamp 11 p Level camera. White - FIG. 8 -VIDEO PROCESSING CIRCUITS in typical vtr. clip diode (waveform) prevents overloading of modulator. Video processing In those machines that provide record -only operation, the video processing circuits are quite simple. Fig. 8 is the basic block diagram. Input video is amplified to provide the level of signal needed to drive the modulator. A low -pass filter usually precedes the video preamp to take out those high video frequencies that are not normally passed by the system and to prevent beats that might result from excessive FM deviation. Pre -emphasis, to improve the signal - to -noise ratio (just as in broadcast FM), is also accomplished in the preamp. Following the preamp is a clamp to tie down the tips of sync to a set dc level. This level determines the sync -tip frequency at which the FM modulator operates. An emitter follower direct -couples the clamped signal to the modulator. The modulator is an astable multivibrator whose TRIPOD A R- connects to the output of the emitter follower. RANGEMENT in hase- return Sony's vtr camera A positive -going (white) signal raises the base voltage, (above) provides which brings the cut -off transistor back into conduction. stable base for some shots. Pana- In other words, a positive -going video signal increases sonic's NV -3080 the repetition rate of the multivibrator. In Sony's DV -2400 only (left) weighs is 1.9 MHz and the video level is 21 pounds with its the sync -tip frequency camera and bat- adjusted so that the peak -white part of the signal pushes teries, and uses 1/2- to 3.2 MHz. A white -clip diode shears inch tape. the modulator up off signals that might push the modulator past the maximum deviation value. (White compression is much less noticeable in the picture than overmodulation noise.) The multivibrator is special in one regard: great pains are taken to insure strict waveform symmetry. This is required so that the carrier (1.9 MHz) can be removed completely by frequency doubling in the detector (during playback). Unless the FM signal is really symmetrical, residual carrier survives the filter that follows the FM detector and appears in the picture just like ordinary FM interference. Following the FM modulator. a power amplifier drives the video recording head. Since the recorded signal is an FM square wave. saturation recording is used: record current is adjusted to drive the tape into saturation on both CONCORD'S VTR - polarities of signal swing. 400 (inside case) uses '. -inch tape running at 12 ips. Cameras It has two rotary The cameras used with portable vtr's require special heads on both record and playback, design since they must operate from 12 volts dc, serve the and has 14 -min re- (continued on page 62) cording time. Circle 5 on reader service card 12 CALMS TAPE TENSION. Headache? Take aspirin. Tape tension trouble? Take TEAC. For instance, take the A -6010U stereo tape deck here - with its unique tape tension control system: an inertial flywheel and compliance arm for precision record /playback running speeds and smooth, fast winding. This system helps reduce external factors contributing to wow and flutter, such as warped reels and splices. TEAC offers fast relief for other common complaints, reverse too: unique phase sensing auto operates electronically at any chosen point on the tape, or takes a sensing foil if you'd rather. Separate heads permit source- or off-the-tape monitoring while recording for easy A/B comparisons. And our exclusive symmetrical control system makes tape handling logical and easy - fast or slow, forward or back, at a flick of the finger. This tape deck can't cure everything that ails you, but you're bound to feel better once you own one. TEAC NMI ROHM TEAC Corporation of America 2000 Colorado Avenue Santa Monica, California 90404 Don't shoot till you see orrespondence the tenths of a volt. C The sure way to troubleshoot solid state TV is with a scope that measures DC. J Take Leader's five -inch LBO -53B: TUNE -UP TIPS It gives you a drift -free DC In the April issue the article, input, so you can see those "Tune Up Your Car With a VOM," tenths of a volt. It gives you a was very interesting. However, there bandwidth to 10 MHz. And it worth noting: gives you a sensitivity of are two points timing on 10 my /cm or better. (1) When setting the make certain that Now for the shocker. You can a four -cycle engine, to the have a Leader LBO -53B for the distributor rotor is pointing cylinder. since the just $229, about half the price contact for the one the flywheel or har- of any other scope with the timing mark on same capabilities. monic balancer is at its timing position for two different positions of the L8O-5I0 OSCILLOSCOPE Since the proof is in the seeing, we direct you to your distributor rotor. Leader distributor. Ask to see (2) An unmodified VOM can be our color bar generators too; used to measure the "dwell" by mea- you haven't seen the finest suring the voltage from the ignition until you've seen Leader's. switch terminal of the ignition coil to ground when the engine is running, Seeing is believing. and comparing this measurement with a measurement when the engine is Leader Instruments Corp. stopped with the points closed. The 37 -27 27th Street, Long Island City, N. Y. 11101, (212) 729 -7411 same type of calculation as set forth Circle 6 on reader service card in the article would be used to deter- mine the "dwell." This method is actually measuring the voltage drop we get thru where others fail across the ignition resistor, which is - not shown in the article. DANIEL E. SRAGOW OPERATES ANYWHERE -INDOORS, OUTDOORS..: STEEL BLDGS. 74 Westerloe Avenue SONARCOM Rochester, N. Y. 14620 LF- VHF -UHF JAPANESE ENGLISH FM TRANSCEIVERS Surely a problem for all tech - Professional performance! Perfectly designed to cive the nicians who have ever had the occa- ultimate in dependability for continuous heavy duty use. sion to perform repair work on for- Provides instant voce contact with base stations. eign equipment is the deciphering of mobile units and other portable transceivers the instruction manual from the man- Compatible with all 2 -way systems ufacturer. Full frequency range for all public safety, industrial recently purchased and land transportation services 1.6 watt output My company units and Receiver and transmitter can be operated on inde- several Japanese facsimile pendent frequencies placed them into operation. Our first Sensitive, noise immune squelch case of trouble on one of these units Plugs for antenna, earphone and battery charger occurred this past month and sent me 5, 00 running for the tech manual that Model 2301 :37500 model 2303A $47 132174 MHz 321.41 MHz 42.50 MN: came with the units for help. VHF -FM 1 CHANNEL LF -FM 2 CHANNELS' 1 pair of crystals and 1 set I pair of crystals. I set of Having fully concluded that of standard batteries. standard batteries less tone' something in this manual was lost Model 2301A Model 2302 $59500 translation, I thought you 131.174 MHz $47500 through VHFFM 2 CHANNELS UHF-FM 1 CHANNEL would enjoy hearing a couple of 1 1 set of 1 pair of crystals and 1 set pa of crystals. of standard batteries. standard batteries and Tone quotes from this manual. 'Model 2303A available wi h tone at additional charge. "Generally speaking, the transistors operated with high voltage tend RADIO CORP., 73 Worturan Ave., Bklyn, N.Y. 11207 SONAR be Please send information on the SONARCOM. Dept. 900 to broken." "(If such transistor trouble Name should be caused, a short circuiting Address phenomenon will develop between the very City stat. zip emitter and collector often.)" (continued on page 20) Circle 7 on reader service card RADIO -ELECTRONICS 14 the set choice is yours...

the antennaI1VGa choice is...

NEW '70 SERIES r °v ANTENNAS

Send for free Catalog 20-556 Of IN( SOILS ¡, THE FINNEY NAME >: r- COMPANY ADDRESS F/NC 34 WEST INTERSTATE STREET DEPT. CITY STATE ZIP a.nnnw J RE -8 BEDFORD, OHIO 44146 Circle 8 on recaler service curd AUGUST 1970 15 Discover the ease and excitement of learning Electronics with programmed equipment N When you trina a t home wRith N I, train with your hands as well as your headyou . You sends you learn the WHY of Electronics, Communica- than tions, TV -Radio the NRI pioneering "3- Dimensional" way. NRI training is the result of more half a century of simplifying, organizing, dramatizing subject matter, and providing personal services unique for a home study school. You get the kind of technical training that gives you priceless confidence as you gain experience equal to many, many months of training on the job. NRI-The 53 Year Leader in Electronics Training

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RADIO -ELECTRONICS 16 Earn $5 or more an hour There's money and Move ahead in America's spare or full time in success awaiting you in fast growing industry as TV- RADIO BROADCASTING - ELECTRONICS SERVICING COMMUNICATIONS TECHNICIAN Color Television has arrived. Sales The experience you gain from in- Electronics touches everyone's lives. are soaring, along with the continu- tensely practical NRI training in This vast field of opportunity is open ing popularity of other home enter- Complete Communications equals to you with NRI training. Industrial/ tainment equipment like portable as much as two years of training on Military Electronics training -like all radios, tape recorders, hi -fi sets, the job. With NRI, you can train fora NRI courses -prepares you quickly, phonographs and auto radios. TV- choice of careers ranging from mo- thoroughly the practical "hands on" Radio servicing is one of your best bile, marine and aviation radio to way. You build with, and learn to un- routes to spare -time earnings, a TV broadcasting and space commu- derstand the functions of, today's good paying job or a business of your nications. You learn how to install, miracle solid -state components like own. NRI not only trains you quickly maintain and operate today's re- printed circuits. diodes and transis- and expertly, but also shows you markable transmitting and receiving tors. You build and experiment with how to get started in Servicing soon equipment by actually doing it. You Electronic circuitry used in automa- after you enroll, earning as you build and experiment with test equip- tion, data processing, ultrasonics, learn. NRI trains you in today's ment, like a VTVM you keep. You telemetry. Whatever your interest in methods of installing and repairing build and operate amplifier circuits, Electronics, NRI training can fill your all Electronic equipment for the transmission line and antenna sys- needs. Prove to yourself what nearly home -including booming Color TV. tems, even build and use a phone -cw a million NRI students could tell you You even build, experiment with and transmitter suitable for transmission ... that you get more for your money keep to enjoy your own solid -state on the 80 -meter amateur band. from NRI. Check the postage -free radio and your choice of black -and- Whichever of five NRI Communica- card and mail it today for your FREE white or Color TV receiver. Like tions courses you choose, you pre- NRI Color Catalog. No salesman will thousands of others, you can be pare for your FCC License exams, call. NATIONAL RADIO INSTITUTE, earning $5 or more an hour extra in and you must pass your FCC exams Electronics Division, Washington, spare time starting soon. or NRI refunds your tuition in full. D.C. 20016.

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AUGUST 1970 19 CORRESPONDENCE Enjoy Relaxing Background (continued from page 14) ARTISAN Music at Home with . . . ALL "Check the existence of voltage TRANSISTOR or power. If there exist no voltage NO COMMERCIALS! If Well, on the case of trouble that I had, I decided to check and see what was to be said in the section "Elec- trical Trouble Shooting" which I discovered in the table of contents. Lo and behold it sure had plenty to say. I'm not too sure what it is, but it must explain my problem: "The electrical troubles which might be caused in the respective elec- Size: 61/2 x5x21 tronic circuits adopted in this equip-

CLASSICAL end THEATER styling for all CHURCH HOME - Our SCA -1 Decoder makes possible reception of ment may be corrected corresponding PROFESSIONAL applications this "private" musical programming, transmitted to the general electronic equipment." by nearly 400 FM stations around the country. ARTISAN tonal concepts consoles and related mechanics DAVID L. DOWNING are completely TRADITIONAL in design YOUR FM tuner or receiver can recover this "hid- den" music with a simple addition of an SCA -1. 4432 Pommore Drive Individually keyed osullatgss and independent sets of Hook -up in minutes -full instructions supplied. Mich. 48042 tone generators with separate amplifiers and speakers Milford, SCA -1 is self powered . . . uses all solid -state assure the finest sound circuitry (FET'S, IC's, NPN's). Works with any CAREER IN AVIONICS Distinctly voiced solo stops that blend in grand ensemble quality FM Tuner or receiver. Send check or m.o. Assemble your own organ and save 40 % -12 models in KIT or assembled form In addition, we custom build to SCA-1 (Wired, ready to use) $64.50 The article by Len Buckwalter on your specdicatuns SCA-1K (Kit, all needed parts) $49.95 careers in aviation electronics was Tailor your owl sound with PLUG IN adjustable voices Etched, drilled P.C. Board plus special IC interesting. I'd like to know if a variable VIBRATOS and TREMOLOS, sustain reverbera plus full construction plans $12.50 service technician would have any lion and REAL PERCUSSIONS. (New York State residents add Sales tax) difficulty entering the avionics field. For descriptive literature and address of your nearest One year parts guarantee dealer. JOHN MASON Free national SCA station list supplied with every order. SOLD FOR HOME USE ONLY New York City Write AN ORGANS SCA SERVICES CO., INC. 128 E. Wheeler Ave. Box 601 -RE Port Washington, N.Y. 11050 Any qualified service technician Arcadia, Calif. 91006 (516) 883 5694 213. 445.1707 wino knows how to troubleshoot color TV or stereo should easily make the Circle 9 un recider service card Circle 10 on reader service card transition into avionics. Many of the signals are similar, though put to unfamiliar use. Take signal phase, for example, which encodes hue information in a Greatest value in soun color TV receiver. In an aircraft receiver, signal phase constructs a :magnetic heading in compass degrees from for every PA a navigational ground station. Precision has led the application field in quality and de- Another similarity is in pulses; in pendability for 25 years. Most trouble -free line in the industry, Precision a TV receiver they provide picture offers a complete range of amplifiers in every sync and blanking-in an aircraft they provide radar power range including mobile, and a complete line of accessories. and the DME function described. So there's considerable From the smallest office to large auditorium or industrial installations, over- lap between the two fields. Precision gives maximum flexibility and performance. One avionics shop -owner believes the toughest part of the transition is simply learning how to operate aviation electronics gear. Before tackling a VOR receiver, for example, the man must know the meaning of the dial marked "OBS" (Omnibearing Selector) or that "CDI" is "Course Deviation Indicator ". On the transmitting end, S-30MAC tine equipment is mainly VHF -AM, S-25-30 and an FCC commercial ticket is good 60 -100 evidence of proficiency in this area. LEN BUCKWALTER DIVISION OF PRECISION ELECTRONICS, INC. Georgetown, Conn. NM KING STREET, MAIM PUn, IWINIS 10131 1 NAME COMING NEXT MONTH TV set owners today want * ADDRESS 1 clean reception for quality pictures. O CITY STATE ZIP Learn how to select antennas and lead -in. 47 *i ostrea m wellesimusBR Circle I1 on reader service card 20 RADIO -ELECTRONICS When you're young your ears are sharp your pocket book is flat And can you hear every dB of difference between The amp has 44 watts of IHF puvver, a front-panel what you can afford and what you'd Ike to. Aux input, high filter, tape monitor, speaker switching Sony understands. and a sexy, sliding balance control. So we brought out an inexpensive amplifier and And, they sell for one hundred twenty dollars tuner that look and sound almost as good as the each-complete with walnut cabinet. expensive ones. We call the tuner the ST-5600, and the amp the The FM stereo/FM-AM tuner has switchable AFC, TA'1U1O. You'll call them nicer names. solid-state Enjoy these i.f. fi|tero. FET'sand everything you need at your hi-fi dealer. Sony Corporation of America, to bring in all stations rioh|y, clearly, enjoyably. 47-47 Van Dam Street, Long Island City, N.Y. 11101. THE SONYs STEREO TWINS, $120 EACH Circle 12 on reader Aervice card 30 new IC circuits you can use

by R.M. MARSTON nections of the CA3018 are in Fig 1. internally connected to the metal case of The IC houses four silicon transistors. the IC, and should be grounded in most Versatile four -transistor IC oper- Transistors Q1 and Q2 are electrically applications. ates from do to vhf. Build basic isolated and can be used independently. Since all our transistors in the Transistors Q3 and Q4, on the CA3018 are etched on a single slab of amplifiers, hi -fi stereo preamps, other hand, share a common base -to- silicon, their characteristics are inevita- icing and temperature indicators, emitter terminal, so these units are con- bly very closely matched to one another, nected basically as a Darlington or Su- even though the characteristics of indi- light- operated switches, elec- per -Alpha pair. Each transistor of the vidual IC's may vary over fairly broad tronic locks, meter amplifiers, connected pair is, however, indepen- limits. Also, all four transistors inevita- Schmitt triggers and more dently accessible. A diode (shown dot- bly operate at almost identical tempera- ted) is effectively connected between the tures, so their characteristics remain collector of each transistor and the closely matched over a very wide tem- substrate (pin 10) of the IC. These perature range. Transistors Q1 and Q2 ONE OF THL SIMPLEST YET MOST VERSA - diodes occur as an incidental part of the have a near -perfect hrr: (dc current devised is the tile integrated circuits yet IC manufacturing technique, and have gain) match over the temperature range Its CA3018 by RCA. manufacturer de- no effect on circuit operation in most -55 °C to +125 °C. this modestly priced (under scribes $2) applications. The substrate (pin IO) is The general characteristics of the unit, which is housed in a 12 -lead TO-5 sized case, as an "Integrated- Circuit Tran- sistor Array." INTERNAL CIRCUIT OF THE CA3018 Characteristics of the CA3018 The device houses four indepen- NOTE: S ° SUBSTRATE V,.,,,, (max) [each transistor] ... 15V dently accessible silicon transistors in V. (max) [each transistor] ...20V the single package. The package offers a 12 VF,,,,) (max) [each transistor] 4V theoretical total current gain of roughly Max collector -to-substrate voltage [each 25 million times. 03 -t - - transistor] 20V I,. (max) [each The four transistors in the package 04 transistor] 50 mA are not "ordinary" transistors. They are I,.,,0 @ 25° [each vhf types, with typical fT transistor] 0 1µA (max) (gain /bandwidth product) figures of 400 1 f,. [each transistor, substrate MHz, and are tested to military stan- grounded] 400 MHz (typ) hey, @ ImA [each dards. They can be operated over a 5 -55 °C to +125 °C temperature range. transistor] 67 (typ), 30 (min) 5 h,.,, ImA [Q3 -Q4 Most important of all, they are all 0I - @ - 02 pair] 3500 (typ), 1500 (min) etched on the same slice of silicon, and thus have very closely matched charac- 3 Q1 -Q2 input -offset voltage @ le, = teristics. and operate at the same sub- I,.., - 1 mA ... 1 mV (typ), 5mV (max) strate temperature. Q1 -Q2 temperature coefficient of 10 4 These features enable this IC to input -offset voltage @ le, - lc_- out -perform normal transistors in most lmA 10µV / °C (typ) (max) [each mW circuits. In some instances use of the Pr transistor] ... 300 CA3018 permits devising circuits to do Pror (max) [total package] ... 300 mW jobs that would be economically impossible using normal transistors. An outstandingly versatile IC, the FIG. 1- TRANSISTORS Q1 AND Q2 are CA3018 can be used in hundreds of in- electrically isolated, although the common teresting applications. In this article, we substrate gives them an excellent hF, over will show you 30 of the many practical PIN CONNECTIONS OF THE CA3018 a wide temperature range. Transistors in Q3Q4 pair may be operated independent- projects you can build around it. NOTE: PIN 10 INTERNALLY CONNECTED TO CASE. ly. The internal circuit and pin con- 22 RADIO -ELECTRONICS DEPENDABLE LEADER IN 1 ELECTRONICS TRAINING 10 Reasons why RCA Home Training For over a half century, RCA Institutes, Inc._ has been a leader in technical training. is your best investment

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Classroom training also available. Free catalog on request. Send coupon today for tree descriptive book L J AUGUST 1970 23 R2 as a CA3018 are tabulated in Fig. I. Note a collector current of 1 mA, so the IC RI acts as a collector load, and that all transistors have a typical fT can be used in high- current -gain and bias resistor that sets the quiescent col- (with pin IO grounded) of 400 MHz, so high- input- impedance applications. lector potential at roughly half the sup- the IC can be used in applications rang- Finally, note that Ql and Q2 have ply voltage. The bias currents are sub- ing from dc to vhf. Also note that the their forward base -to- emitter voltages ject to negative feedback, so good Q3 -Q4 pair has a typical hrE of 3500 at matched to a typical value of I mV. stability is obtained from this simple ar- with a typical temperature coefficient of rangement. +3 TO 15V only 10 µV / °C (compared to 2 mV / °C The circuit can be operated from of a single conventional transistor), so any dc supply in the range 3 to 15 volts. C2 the well suited to 9 -volt supply, the design gives a IOµF IC is outstandingly Using a high- performance dc differential am- voltage gain of about 43 dB, has an in- -71 plifier applications. put resistance of 1500 ohms and an out- R2 390K put resistance of 6800 ohms. The fre- Basic connections of the unit quency response of the circuit extends CI 30 Hz to several hundred kHz. IOpF The CA3018 is fairly easy to use, from since it can be regarded simply as a Similarly, Fig. 3 shows how the IC OUTPUT block housing a number of normal can be used as a simple emitter follower, T4 (more or less) and independent transis- using Q4 only. Here. R 1 is used as the INPUT tors. Transistors QI and Q2 can be re- emitter load, and R2 is the bias resistor, garded as totally independent and can again operating in the negative feedback be used either individually or simulta- mode. The circuit can be used with any neously, without restriction. Similarly, 3 -to 15 -volt dc power supply. Using a 9- each of the Q3 -Q4 pair is independently volt supply, the circuit has an input re- accessible, so either of these devices can sistance of 220,000 ohms, unity voltage USING A 9 -V SUPPLY be used as an independent transistor, so gain and a frequency response that ex- AV 43dB long as the other member of the pair is tends from 30 Hz to several hundred RIN 1.5K left unused. kHz. Note in both Fig. 2 and Fig. 3 that ROUT 6.8K For example, Fig. 2 shows how to connect the IC as a simple common - Q3's emitter is connected to Q4's base FR 30Hz- 700KHz as an +_3dB emitter amplifier, using Q4 only. Here, and does not restrict the use of Q4 independent transistor, so long as Q3 is FIG. 2- COMMON -EMITTER AMPLIFIER left unused. The IC can thus be used connections for using only Q4 in the Dar- +4.5 TO 15V three indepen- lington pair. The IC will operate over a simply as a block housing wide dc supply range, providing a 43 dB RI C2 dent transistors (with Q3 unused), if re- gain with 9 volts. 6.8K 10p quired. +3 TO 15V Such an approach would. of course, R2 be rather wasteful of circuit potential. MEG 10 since both transistors in the Q3 -Q4 pair 12 CI can be used simultaneously in a number .22 of ways. One way of doing this is to w OUTPUT ground pin 2 of the IC and then use Q3 as a common- emitter amplifier (with input to pin 9) and Q4 as a common -base INPUT amplifier (with input to pin 1). Alternatively, Q3 can be used as an emitter follower, with its output feeding directly into the base of common -emitter amplifier Q4. A number of other USING A 9-V SUPPLY: basic ways of using the Q3 -Q4 pair are AV 40d8 shown in Figs. 4 through 7. Fig. 4 shows how to connect the IC RIN 82K USING A 9 -V SUPPLY: so Q4 is used as a simple common -emit- RIN 220K ROUT 6.8K ter amplifier with built -in protection against damage by excessive input sig- FR 30Hz- 700KHz FR = 30Hz- 250KHz ±3dB +_3dB nals. Here, the base -emitter junction of as a reverse- biased silicon FIG. 3- EMITTER- FOLLOWER circuit FIG. 5- SUPER -ALPHA PAIR Q3 -Q4 used Q3 is used using only Q4 offers a voltage gain of as 40-dB gain common -emitter amplifier. diode between Q4 base and ground. unity. If excessively large input signals are connected to the circuit, this diode be- +9 TO 18V comes forward- biased on the negative - going parts of the signal. and insures that the emitter -to -base ratings of Q4 are not exceeded. With normal signal inputs, the diode is inoperative and the performance of the amplifier is identical to that of Fig. 2. Fig. 5 shows how Q3 -Q4 can be connected as a Super -Alpha pair for use as a common -emitter amplifier with a high input resistance. This particular circuit can he used with any supply in the 4.5- to 15 -volt range. Using a 9 -volt supply, it delivers 40 dB voltage gain, has an input resistance of 82,000 ohms, an output resistance of 6800 ohms. and a frequency response within 3 dB from 30 Hz to about 250 FIG. 4- PROTECTED COMMON -EMITTER FIG. 6- CONSTANT- CURRENT GENERA- amplifier uses Q3 as diode to limit signal TOR uses Q3 like Zener diode. Q4 is cur- kHz. to Q4. rent source. Fig. 6 shows how the Q3 -Q4 pair 24 RADIO- ELECTRONICS We guarantee the CRT... the rest is your business

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Circle 13 on reader service card AUGUST 1970 25 can be used as a constant- current gener- The collector current of Q4 is dictated forward base -emitter voltage drop of ator. Here, the base -emitter junction of almost entirely by the value of Zener Q4) over the supply -line range of 9 to Q3 is heavily reverse -biased from the 9- voltage on Q4's base and by the values 18 volts and over the output- current to 18- volt positive supply line via R I. of R2 and R3. It is substantially inde- range 0 to 20 mA. The circuit acts as a The reverse base- emitter breakdown pendent of the value of collector load constant -voltage source. voltages of the transistors in the resistance and supply -line voltage (so CA3018 are very sharply defined at long as Q4 does not run into satura- High- input -impedance amplifier about 6.5 volts, so Q3 acts as an ex- tion). Therefore, Q4's collector (pin 12) It has already been mentioned that. cellent Zener diode, and applies a fixed acts as a constant current source. because of the high available current potential of roughly 6.5 volts to Q4's The circuit can be used with any gain of the CA3018, the IC is suitable base almost irrespective of the actual supply in the 9- to 18 -volt range. With an for use in a variety of high- input -imped- supply -line voltage. Transistor Q4 is 18 -volt supply, the constant -current ance applications. In this section, we will wired as an emitter follower, with an ex- magnitude can be set (via R2) at any look at three amplifier projects that use ternal load connected in series with its value between 0.4 mA and 14 mA. these high- impedance techniques. collector, and with resistors R2 and R3 Finally, Fig. 7 shows how the We have already seen, in Fig. 5, wired between its emitter and ground. Q3 -Q4 pair can be used as a constant - how the Q3 -Q4 pair can be used as a voltage source. Here. Q3 is again used common- emitter amplifier with a high as a Zener diode, with its Zener voltage input resistance. One snag with this par- fed directly to the base of Q4. And Q4 ticular circuit, however, is that it has the is wired as an emitter follower. moderately high output resistance of In this circuit, however, Q4's collec- 6800 ohms. Consequently, appreciable tor is taken directly to the positive sup- resistive or capacitive loading of the ply line, and the output of the circuit is output inevitably causes a substantial taken from Q4's emitter. loss in either voltage gain or upper fre- Due to the emitter -follower action quency response of the circuit. This can R2 OUTPUT of Q4. the potential at the output of the be overcome by using the connections 4,7K ti_ circuit remains virtually constant at shown in Fig. 8. I6V about 6 volts (Zener voltage minus the Here. Q3 and Q4 are again used as a Super -Alpha pair and are connected in +4.5 T0 15V the common -emitter mode. But this time FIG. 7- CONSTANT -VOLTAGE SOURCE an extra transistor, Q2, is wired as a di- uses Q3-Q4, applying Q3's Zener voltage R2 rect- coupled emitter follower between to Q4. MEG 10 the Q3 -Q4 collector load and the circuit output at pin 4. . -+4.5T015V C3 The complete circuit thus has a RI 0.1 high input and low output resistance, 6.8K and its gain and frequency response are not greatly influenced by output loading R2 CI conditions. The circuit can be used with 10 MEG 0.1 7 any supply between 4.5 and 15 volts. C4 When used with a 9 -volt supply, it deliv- 10µF CI C2 C2 ers a voltage gain of 38 dB, has an input 10µF INPUT I .22 IOµF resistance of 82,000 ohms. an output re- C OUTPUT sistance of 270 ohms and a frequency INPUT 2 2 10 response within 3 dB from 30 Hz to 250 R3 kHz. OUTPUT I 6.8K INPUT OUTPUT When very high input impedances are required, the IC can be used as a R3 4.7K Super -Alpha connected emitter -follower FIG. 10- STEREO EMITTER -FOLLOWER mode (see Fig. 9). Transistors Q3 and circuit like Fig. 9, using all four transis- Q4 are used as the Super -Alpha pair. tors. The circuit works with any supply from 4.5 to 15 volts. and has an input SI USING A 9 -V SUPPLY: resistance of about 5 megohms. The fre- Av 38 dB quency response of the circuit extends from less than 10 Hz to several MHz. 82 K RIN The circuit works as a high -performance ROUT ' 27011 preamp for crystal or ceramic pickups. FR 30Hz- 250KHz ±3dB Finally, Fig. 10 shows a stereo ver- FIG. 8- COMMON- EMITTER AMPLIFIER sion of the Super -Alpha emitter fol- has high input and low output resistance. lower. Two complete circuits, each identical to Fig. 9, are built from one IC. One circuit is built around Q3 and Q4, and the other around QI and Q2. Since all four transistors in the CA3018 are closely matched, the two circuits give virtually identical perform- ances. This project is thus perfectly suited for use as a hi -fi stereo preamp for crystal or ceramic pickups. ÓµF Relay- driving projects NOTE: DI, D2 GENERAL PURPOSE The can be used in a num- OUTPUT SILICON DIODES. CA3018 ber of interesting relay- driving appli- RYI 12 ANY -V RELAY WITH example, Fig. 11 shows A COIL RESISTANCE cations. For how GREATER THAN 24011. to connect the IC so it instantly triggers a relay when pushbutton switch SI is FIG. 9- CERAMIC -CARTRIDGE amplifier FIG. 11 -RELAY DRIVER operates RY1 has 5- megohm input resistance using Q3, from Q3-Q4 pair, deenergizing relay after momentarily operated, and turns the re- Q4 and Q2. 12 sec. lay off again automatically after a fixed 26 RADIO -ELECTRONICS Discovery in the art of performance

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And, remember, for further professional needs, RCA also produces the renowned BK and SK microphone lines. RC,' Circle 14 on reader service card AUGUST 1970 27 delay of about 12 sec. Longer delay pe- 1S1 when SI is released. As soon as the sup- riods can be obtained by increasing the ply is connected to the circuit via SI, Cl value of Cl. starts to charge exponentially via RI. As Circuit operation is simple. Transis- Cl charges, the voltage at pin 2 and the tors Q3 and Q4 are wired as a Super - current into Q2's base start to fall slowly Alpha emitter follower, with the relay as +12V toward zero. Consequently, after a delay the emitter load, and the input of the of about 2 min, Q2's base current falls emitter follower (pin 9) is taken to the to such a low value that Q2 turns off junction of RI and C 1. and the relay is de- energized. The con- Circuit operation is initiated by mo- tacts open, breaking the supply to the mentarily closing SI. At the instant that circuit. CI then discharges rapidly via SI is closed, Cl is fully discharged, so D1 and R4. The circuit is then ready for pin 9 is effectively shorted to the posi- the next operation of SI. tive supply source at this time, and the The important point to note about relay is driven on by emitter -follower this circuit is that RI is not connected action. As the relay goes on, contacts directly between Q4's base and ground. RY1-1 close and keep the supply voltage Instead it is wired between Q4's base connected to the circuit when Si is then and emitter and then to ground via R2 released. and R3. As soon as the supply is connected Due to the emitter -follower action via Cl starts to charge of Q4. the voltage across R1 is constant to the circuit SI, NOTE: DI , D2 GENERAL PURPOSE exponentially via R1. As it does, the SILICON DIODES. at about 0.65 volt, and changes of volt- 2 voltages at pins 9 and 1 fall slowly to- RYI - ANY 12-V RELAY WITH A age on pin cause only negligible ward zero. After about 12 sec, the volt- COIL RESISTANCE GREATER changes in RI's current. R1 is thus THAN 2408. age at pin I falls to such a low value "bootstrapped" and appears, to varying that the relay turns off. As the relay FIG. 12- LONGER DELAY for relay is pin 2 signals, as an impedance of several in this configuration for RYI -1 open and achieved circuit megohms. turns off, contacts the IC. break the supply to the circuit. Then Cl To steady dc signals, on the other discharges rapidly via Dl and R2. The hand, R1 appears as a simple resistance circuit is then ready for the next oper- of only 120,000 ohms. Thus, R 1 appears SI. +12V as a very high resistance to the ex- ation of SI The circuit shown above is designed ponentially varying charging currents of around Q3 and Q4 only. It can be used Cl, but appears as a moderately low re- equally well with Q1 and Q2. Thus, two sistance to steady Cl leakage currents. complete circuits of this type can be The circuit, therefore, generates very made from a single IC. In the circuit, long time delays without problems from D2 ensures that the IC is not damaged CI leakage currents. by back emf from the relay coil as the Another way of connecting the IC relay switches on or off. The relay can as a relay -driving time -delay circuit is in be any 12 -volt type that draws an oper- Fig. 13. Here the circuit does not turn ating current of less than 50 mA-one the relay on until about 12 sec after SI that has a coil resistance greater than is closed. The circuit is similar to Fig. about 240 ohms. I I, with Q3 and Q4 connected as a Su- The time delay of the Fig. I1 cir- per -Alpha emitter follower that uses the cuit is controlled primarily by the time relay as its emitter load, and with pin 9 NOTE: DI , D2 GENERAL PURPOSE constant of R 1 and C 1. The larger the SILICON DIODES. connected to the C1 RI junction. This of these components, the time, the positions of CI and R1 are re- value of either RYI ANY 12V RELAY WITH A longer the available time delay. In prac- COIL RESISTANCE versed in the circuit. tice, however. the maximum usable GREATER THAN 24011, When SI is first closed, Cl is fully RI is to about discharged. so pin 9 is effectively value of restricted FIG. 13 -TIME -DELAY RELAY DRIVER 100,000 ohms. If larger RI values are energizes RY1 about 12 sec after SI is shorted to ground. Due to the emitter - used, the high leakage currents of elec- closed. follower action of Q3 and Q4. pin 1 is trolytic capacitor Cl may generate such also held at ground potential, and the voltage on pin 9 that the relay is relay is held off at this stage. a large +12V unable to turn off. Fig. 12 shows a cir- As soon as SI is closed, Cl starts to cuit that overcomes this snag, and gives charge exponentially via R1. As it a turn -off delay of about 2 min. from a charges, the potentials on pins 9 and I standard 100-AF electrolytic capacitor. start to rise slowly toward the positive This circuit uses only Q2 and Q4. C supply. After a delay of about 12 sec. Transistor 02 is wired as a common - METAL pin l's voltage reaches such a high value emitter amplifier, with the relay coil as PROBES that the relay turns on. The relay re- its collector load. Transistor Q4 is wired R2 mains on until SI is opened again. As 12 as an emitter follower. with its emitter 22K soon as SI is opened, Cl discharges ra- current feeding into Q2's base via limit- pidly via R2 and Dl. The circuit is ing resistor R2. and with its own base ready to operate again as soon as Si is (pin 2) connected to the junction of Cl closed once more. and RI. Resistor RI is the main time - Fig. 14 shows how to connect the constant unit. and is wired between Q4's IC as a sensitive water- operated switch, ground via Q4's emitter and RI 610 with a relay output. Circuit theory is base and IOOK R2 and R3. simple. Transistors Q3 and Q4 are con- Circuit action is initiated by briefly nected as a Super -Alpha pair, wired in 1 closing SI. At the instant SI first closes, the common- emitter mode, with the re- CI is fully discharged. Pin 2 is NOTE: DI GENERAL PURPOSE lay as the collector load and with input effectively shorted to the positive supply SILICON DIODE. applied to pin 9. This pin is connected and Q2 and the re- RYI ANY 12 -V RELAY WITH A to a metal probe via limiting resistor R2 line at this moment, COIL RESISTANCE lay are driven on by the emitter fol- GREATER THAN 24011. and to ground via RI. A second metal probe is connected to the positive sup- lower action of Q4. As the relay is ener- FIG. 14- WATER- OPERATED SWITCH gized its contact closes, keeping the uses Q3Q4 in common- emitter mode to ply for the IC. supply line connected to the circuit turn RY1 on. (continued on page 73) 28 RADIO- ELECTRONICS "Hard work's not enough ... you need more education to get ahead in

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AUGUST 1970 29 NEW COLOR Hobbyist -priced color TV cameras are only a few years off. Here's a look at new techniques that will make them possible TV CAMERAS

by WALTER G. SALM

'SCRAMBLER' made for ABC by Ampex uses field sequential scanning system.

THE MONOCHROME TV camera has become so firmly en- trademark both ingenious and logical, being derived from trenched as a closed-circuit and experimenter's item that we the Greek root word plumbos for "lead." no longer think of its presence as a curiosity. The reason: The sheer magnitude of the Plumbicon's development low -cost, made possible by production corner -cutting, sec- is revealed by the fact that RCA and GE were both quietly ond- quality Japanese vidicon pickups and the wide toler- using "lead -oxide mesh vidicons" (purchased from Phil- ance latitudes possible in "home" and low -cost commercial ips) in their advanced color cameras in 1968 and '69. By applications. A black- and -white vidicon camera can be had the end of 1969, GE proudly announced it had developed for as little as $200 today (in kit form from Conar) and its own lead -oxide mesh vidicon and planned to use it for somewhat more for transistorized ready -mades. broadcast TV cameras. The difficulty in setting up quality When it comes to color cameras, the story is vastly production of this tube is borne out by the fact that GE is more complicated. A color camera is basically three cam- still buying Plumbicons from Philips. eras in one, with lots of extra circuits. It must first break Color cameras settled into a fairly fixed -price mold for the image down into its three TV primary colors of red, a couple of years. Any broadcaster, school system or pri- blue and green. vate citizen who wanted one could go out and buy it for about $65,000 to $85,000- depending on options. Ob- Three or four pickups? viously. at such a price, color was out of the question for most schools, colleges, small TV stations, CATV operators This is done in three- pickup cameras through an op- doing local origination, and certainly the experimenter and tical system that generally consists of two semi -silvered TV ham. mirrors, two filters (red and blue), two more mirrors or But in 1967. things began to happen. One little -her- prisms and a series of field- correcting and compensating alded but significant development came out of Japan. Nip- lenses. pon Columbia succeeded in producing color TV images The only pickup that gets a fairly simple shot at the using a single vidicon tube. N.C. engineers were able to image is the green, since this is also the luminance (Y) produce a prototype camera that weighed substantially less channel in three- pickup cameras. The Y channel brightness than other color units and presumably, in production gets a straight- through shot from the camera's lens with no would also cost quite a bit less. intervening filters. The green color signal is derived later by The camera was tested by NHK -the Japanese na- subtracting R and B from Y. tional TV network -but never got much beyond this point. Optically and electronically, the three -pickup camera It has never been publicly demonstrated, and Nippon Co- is vastly simpler than the four -pickup cameras that are now going out of vogue in the broadcast industry. These latter cameras sought to compensate for overall poor pickup-tube PORTABLE CAMERA requires complex support gear. efficiency by having a separate image orthicon tube for the luminance channel and by providing a filtered green channel. This meant fewer electronic gymnastics but there was the added expense of a fourth imaging device and its associated backup circuitry. Three -pickup cameras were tried in the very early days of NTSC color, but they provided a poor luminance signal. A fourth image- orthicon was added, and the four - pickup camera became the industry standard. Some broadcasters still feel the separate luminance tube provides the best possible signal compatibility. Then along came the first successful commercial TV camera with three pickups -the Norelco PC -70. Until it was introduced at the 1966 National Association of Broad- casters Convention, four tubes was the chosen way. What really made this new camera possible was the development of the separate -mesh, lead -oxide vidicon tube by Norelco's parent company, N. V. Philips Gloeilampenfabrieken. Philips promptly dubbed this tube the Plumbicon -a 30 and is now in production with an approximate price tag of $100,000, in a wireless microwave version. IVC sticks with vidicons

While all this was going on, a small group of engineers calling themselves International Video Corp. -mostly ex -Ampex people -had just completed work on the infant company's compact helical color video recorder. They decided to take a crack at color cameras while they were at it and came up with a three -vidicon unit that really did the job and could be sold for an unbelievable $14,500! This was the IVC -I00 (now discontinued) and the low cost was made possible by using vidicons instead of Plubicons, a fixed, nonadjustable, sealed optical system that could be mass -produced at low cost, and a head largely devoid of the many bells and whistles usually associated with color broadcast cameras. To be sure, the IVC -100 had its drawbacks. Because of normal vidicon lag, the camera couldn't be used for lumbia is vcr tight- lipped about the final results. But the fast -moving sporting events. and it could only be panned camera's underlying principles showed up later in a single - slowly. But it was ideal for small- budget stations going for tube color camera by RCA and in two -tube cameras by color in newscasts and other studio productions: it was just Sony and Toshiba. the ticket for low- budget educational broadcasters and cer- In the meantime, the ABC network decided to push tainly well suited for medical, industrial and other CCTV uses. was for all -out sports coverage. To do this, a light, fully por- CATV also high on the list of interested parties, table color camera was needed. So ABC contributed sub- but there was no pressure from the FCC for local program origination stantial funding to a crash research and development pro- at the time. gram at Ampex for such a camera. The result was the The IVC -100 was soon followed by the IVC -300 -a Ampex BC -I00 (dubbed the "Scrambler ") which in late more expensive ($19,000) version with more bells and 1967 easily gave ABC a scoop on the other networks. whistles, then by the IVC -300, a three -Plumbicon camera It wasn't a cheap camera by any means, running priced at $29,000, and the IVC -90 priced at $7,300. It about $100,000 each with the needed support equipment. looked as though IVC had the low -cost camera market The big news was not so much its portability, but how it sewn up for a while, which indeed it did. IVC cameras were was achieved. For the first time, a color camera had been also private -labeled and sold by Bell & Howell and by made for regular broadcast use with just two pickup tubes. Singer's GPL Division. These two companies also private - As with all portable cameras that followed, the head labeled IVC's videotape recorder, as did RCA, which still itself was trimmed to the bone, with the needed electronics sells the little helical unit. B &H and GPL have both relegated to a backpack. This was done to keep the head weight down to FIG. 1- SINGLE -TUBE RCA PK -730 determines brightness values reasonable proportions for mobility and of each small area scanned, permitting two carriers to be pro- ease of handling. But the cameraman wouldn't win any duced in the decoder. Green is generated electronically. 100 -yard sprints with that 30- or 40 -pound backpack COLOR SCENE STRIPED FILTERS weighing him down. The head itself was something of a throwback. It used (and still uses) a spinning filter disc to separate the red Single Tube and blue color information into a field -sequential signal. A Color Camera straight- through signal feeds the Y pickup tube. Both tubes are Plumbicons. Getting that field -sequential information decoded and LENS into standard NTSC form is no mean feat. Early versions of the camera relied on a videodisc recorder in the camera control unit (at the base station) to provide the needed one -line delay. Later models eliminated the videodisc in favor of a delay line. LUMINANCE The camera got an immediate baptism of fire -first at SIGNAL college football games, then in the subzero cold of Cham- rousse while covering the 1968 Winter Olympics at Gre- noble. ABC scored one coup after another with this camera, and used it again at the Summer Olympics that year in COMPATIBLE VIDEO Mexico City. In the meantime. RCA and CBS Labs weren't sitting on their duffs. They both developed portable cameras that used three pickup tubes and met all the requirements for RF Modulator light head weight and NTSC color output. These entries were hurried to completion for use on the floor at both 1968 presidential nominating conventions. Both the CBS and RCA cameras were engineering prototypes. We can only guess what the CBS Minicam cost, but we understand that the four cameras provided by RCA for NBC cost a cool million dollars each to produce! The CBS Minicam has since been licensed to Philips, AUGUST 1970 NTSC COLOR TV COLOR MONITOR RECEIVER VTR dropped the IVC line in favor of cheaper Japanese equip- from 4.2 MHz to 5.6 Mhz. The green is derived from the ment on the market. combination luminance (Y) channel by subtracting the While all this was going on, RCA unveiled its coup- red and blue signals. the single -vidicon color camera (model PK -730). It was The camera produces surprisingly good color, al- priced (tentatively) at $7,000 or $8,000, but by the time it though the resolution is limited to 250 lines. This is some- finally got into production a year later (last November) what better than the 230 -line resolution of the average the price had risen to $9,000 plus, depending on options. home color receiver, so the two working together in a Light entering the RCA camera first goes through the simple CCTV system can produce excellent results. This lens and through two striped filters -one of cyan and white resolution is a limiting factor only where broadcast use is stripes and one of yellow and white- before reaching the involved. The camera simply can't meet broadcast require- train- pickup tube ( Fig. 1) . The tube target sees the cyan filter as ments, so it's billed as a unit for CCTV, education, a set of stripes, one half of which (the clear white) trans- ing, military, health sciences and research. It's also dandy mits all colors and the other half (red stop) transmits for industrial and other quality CCTV work where color is cyan. Red information won't pass through the cyan stripe, a benefit. but will pass the clear stripe, along with all other color information. The same is true of blue light reaching the More field -sequential types yellow /white filter. No blue is transmitted by the yellow First production units of the RCA PK -730 were de- stripes, but does pass through the white stripes along with livered last fall and full -scale manufacturing is now a real- all other colors. ity for the world's only available single -tube color camera. The pickup tube in effect works in reverse; instead of There are other single -tube color cameras -the field- sequen- detecting the presence of blue and white information, it tial type -mainly made by CBS Laboratories for medical detects its absence. use and by Westinghouse (under CBS license) for the The stripes dissect the image into very small segments, Apollo moon program. The CBS medical version is fairly which are encoded in the form of alternating brightness inexpensive as color cameras go, but backup equipment values. A given segment of the target is programed to read needed to convert field -sequential to standard NTSC type This is red information, another segment blue information. signals is ponderous and frightfully expensive. The only fundamentally an area-sharing system since the selected successful versions of these converters in operation do their areas of the target must not only produce picture detail, work in the Houston Space Flight Center. In the mean- content and brightness value signals, it must also handle time, CBS is working on the electronics for a more reason- color information. The tube is able to distinguish between ably priced converter. red and blue since they reach the target at different bright- If you want to use the field -sequential single -tube cam- red and ness values. The effective number of stripes for era in its medical version, you must also buy a monitor blue is different, so that this distinction can readily be similarly equipped with a spinning filter disc. But the moni- made. tor screen size is quite small -about 8 inches diagonal - The electron beam that scans these stripes generates because of the ponderous size of equipment needed to drive two carriers which contain the red and blue information the disc in larger- screen versions. One big advantage of the (Fig. 2). The luminance occupies the frequency band from CBS camera -its color rendering at extremely low light blue 0 to 2.8 MHz, the red signal 2.8 to 4.2 MHz and levels is quite good. Other special -purpose and low -cost cameras are on the FIG. 2- ELECTRICAL OUTPUT of the RCA one -tube camera. Green is obtained by subtracting red and blue from the full - market. One new unit aimed at the commercial and educa- color image. tional broadcaster is made by Commercial Electronics. Inc., a new California -based company. This camera uses Westinghouse secondary- electron- conduction (SEC) vidi- LUMINANCE CARRIER CARRIER cons -the same pickup tube used in the Apollo field- sequen- I II tial camera. The difference here is that CEI's camera uses RED BLUE of the SEC's in a rather conventional color- camera F three setup. Reason for the SEC's: they give the camera ex- 0 I 2 3 4 5 tremely high sensitivity and can provide a brilliant full - MHz picture at normal room lighting (about 10 foot -can- STRIPED -FILTER camera from RCA costs about 59,000. color dles) at a lens opening of /8. To operate at 10 foot -candles, conventional $80,000 TV cameras have to crank the lens wide open, losing depth of field and generating lots of picture noise in the dark areas. The camera is planned for medium- to low- budget operations such as educational and marginal uhf broadcasters who might opt for truly low -cost cameras. This one is tagged at $32,000. Justification for the somewhat higher price than the IVC cameras is the savings in new studio lighting that's not needed. The camera will work beau- tifully in studios lighted for monochrome; there's no need to add more lights, or more air -conditioning capacity to handle the extra heat, generated by added lights. Japan: still at three figures One of two production -model cameras from Japan to use a striped -filter arrangement is the Sony DXC -5000. Priced at about $5,000, this camera isn't simply a rehash of the Nippon Columbia and RCA cameras. Instead it uses other overlapping areas of technology. The striped filter (continued on page 62) RADIO -ELECTRONICS Color- difference amplifiers 6DM8 or equivalent in NEW R -E EXCLUSIVE tube or hybrid chassis KwÎkFîxT picture and waveform charts by Forest H. Belt & Associates

SCREEN SYMPTOMS AS GUIDES WHERE TO CHECK FIRST

SYMPTOM PIC DESCRIPTION VOLTAGE WAVEFORM PART

Red missing; plate pin 3 WF5 Any around green at both V1 -a sides; blue in middle

Colors smeared; grid pin 8 WF3 L3 green R4 BLUE MAGENTA GREE1:1 dominates; brightness control not correct

Green missing; not WF6 R4 BLUE no phase much change help

No color; raster all WF4 R14 out of focus plate VI and shrunk pins

Raster bars plate pin 3 WF3 R2 all blue grid pin 8 WF6 C4

Green missing; plate pin 2 WF6 Any from right -end BLUE around bars V1 -b

Blue missing; plate pin 1 WF7 Any more than usual RED GREEN around red and green vl -c

Blue very weak; plate pin 1 WF7 C2 RED CYAN GREEN center bars grid pin 9 R7 1 are cyan

'an Easy ReadTm feature by FOREST H. BELT & Associates) 1970 SCREEN SYMPTOMS AS GUIDES WHERE TO CHECK FIRST

SYMPTOM PIC DESCRIPTION VOLTAGE WAVEFORM PART

Colors weak not not R14 and faded, much much R15 even at high help help color setting 11111111

Blue dominates; grid pin 6 WF4 R14 MAGENTA green weak or grid pin 8 blanker missing. Retrace connection visible.

NOTES: Most helpful clues to the fault are found at key test points indicated in Voltage or Waveform column. Use this guide to help you find which key voltage or wave- Make the voltage or waveform check indicated for symp- form to check first. toms you see on the screen. Study the screen colors, with color -bar generator fed into Use Voltage Guide or Waveform Guide to analyze results. antenna terminals. the receiver's lute control set at center, For a quick check, test or substitute the parts listed as the and the color control about two -thirds up. most likely cause of the symptoms.

THE STAGES ponent is not part of the demodulated color signal) are almost SOME CHROMA DEMODULATORS HAVE LOW OUTPUT. THE RECOV- always tubes rather than transistors. ered color signals need amplification before being applied to These color-difference amplifiers are fed from X and Z the color CRT. In hybrid color TV's, the color- difference am- demodulators (see last month's Kwik- FixTm). An R -Y signal plifiers (as they are called when the Y or brightness corn- comes from the X demodulator, and a B -Y from the Z (copy continues on page 38)

C5 .01/IKV

VI-a K R-Y AMPL TO CRT RED GRID 170V RII R8 IOOK 27K LI CI 3W .01 R-Y 620µH 1511 FROM 'pb f X DEMOD R5 330V WF -5 IMEG ?v 210V-P-P R2 C6 .OI/IKV 270K VI-b G-Y AMPL ,T:)'1 TO CRT GREEN GRID C3 R12 .01 R9 IOOK 27K 8 3W vo Ne

L3 MEG 404611 620µH 330V . , r\' R4 3.3K C7 .01/IKV

20V R3 VI-c 270K B-Y AMPL TO CRT BLUE GRID =F. R13 , L2 C2 RIO 620µH\ .01 IOOK B-Y t4 V 27K FROM 3W Z DEMOD 9 R7 I MEG 330V wl- r Dvl,-í' 47011 410" yam' v." R14 20V 250S2 CRT BIAS FROM BLANKER DC VOLTAGES AS GUIDES

Voltage change to zero very low low slightly low slightly high high Plate pin 1 R10 open R3 low C2 shorted R14 open Normal 170 V R7 shorted R7 low V1 dead C2 open L2 open

Plate pin 2 R9 open R4 high R2 low R4 open R14 open Normal 170 V R6 low, shorted R4 high L2 open V1 dead R14 open L3 open at blanker C3 leaky C4 leaky

Plate pin 3 RI low RI low R2 low L2 open R14 open Normal 170 V R5 low, shorted C4 leaky V1 dead R8 open C1 open, leaky L1 open

Grid pin 6 R8 open R5 low, Normal 15 V shorter' R14 open at blanker C1 open, leaky L1 open

Cathode pin 7 L2 open R14 Normal 22 V open

Grid pin 8 R4 open R2 low R6 low, Normal 16 V L3 open shorted R4 high R14 open C3 leaky, shorted at blanker C4 leaky C3 open

Gride pin 9 R9 open R3 low R7 low, shorted Normal 14 V R10 open C3 leaky R14 open C3 shorted at blanker C2 open L2 open

NOTES: Use this guide to help you pinpoint the faulty part. Finally, notice which parts are repeated in whatever All voltages taken: combi- with signal from color -bar generator fed nation of voltage changes you find. into antenna terminals of receiver. Test those parts individually for the fault described. Measure the seven key voltages with a vtvrn. Look for additional chues in the Waveform Guide. For each, move across to the column that describes the change you find. AUGUST 1970 35 WAVEFORMS AS GUIDES

WF1 Normal 15V p-p dr 14 K Ill ilL?u Ij ,I,) t This is the input waveform from the X demodulator. It is red video, but minus the Y portion M1 (R -Y). It is mostly a reference waveform, yet it offers some clues of malfunctions in V1 -A. (r4 1,41 That's because of the small feedback through R1. When phase is right, the third negative bar is longest. Natural blanking is short, and stays near the zero base line.

V p-p low V p-p high V p-p zero ..r liro, e % Cl open f r -. rr ti /. i r'* I ' i i 1 '. 1 '' 1 .1 V 1 . y r' 8V p -p 7V p -p 8V p-p 8V p-p 24V p-p L1 open R1 low R5 low R5 shorted R14 open C1 leaky

WF2 Normal 15V p-p

This is the input waveform from the Z demodulator. It is blue video, but minus the Y portion (B -Y). It, too, gives some pretty good clues to malfunctions in the amplifier it feeds, because of the feedback connection through R3. The first two bars go positive. When 141040 phase is right, the sixth bar is the longest negative one. Blanking is normally short, staying around the zero base.

V p-p low V p -p high V p -p zero y 11 44 1 Iry 11 /0 iMr !., R14 ( I 1 --/ i open'rifl!'r ,rr, r C2 e t open ,r 'rr ' . 1 9V p -p 15V p-p 10V p -p 9V p -p R3 low R7 low R7 shorted L2 open C2 shorted

WF3 Normal 3V p-p

This is the waveform that is made into green video, also minus the Y portion (G -Y). It t' comes from the amplified (and inverted) R -Y signal. The amplitude is small because It IIl of the tiny value of phase-shifting capacitor C4, which is also the only coupling capacitance. in V1 -A. The ninth bar should be the longest negative 1 Blanking is tall, having been added 0 e one. Most of the other bars in this waveform are positive, producing no output when they get to the crt grid.

V zero V p -p low V p-p high p-p pN 1 h R4 high ^ 71 ¡^ , 1! . R6 low R6 shorted 30V p-p 2V p -p 15V p 3V p -p C3 leaky -p R4 open R1 low R2 low R14 open C3 shorted jL3 open R8 open C4 leaky

är111 11 1 i, y ply/ ' .411 1ri

1.2V p -p 3V p-p 1.5V p -p R2 open C1 leaky R14 open C1 open L1 open

WF4 Normal 7V p-p

.W This is a combination waveform, taken at cathode pin 7. The blanking pulse dominates it. ' +',, +,'e The cathode is where blanking is fed in. The color -signal portion of the waveform is com- paratively small. R -Y seems to dominate that -the third bar is furthest negative. Clues to which tube section is in trouble are found in the polarity and amplitudes of bars in this waveform, if you study them carefully.

RADIO -ELECTRONICS 36 WAVEFORMS AS GUIDES

V p -p low V p -p high V p -p zero t iiiiNe a 6r R14 open ,-- i , al 01 R15 open . 0 f i "' 10V p -p 10V p -p 2V p -p 4V p-p R2 low L3 open R14 open R14 open R8 open Cl open C4 leaky L1 open

WF5 Normal 210V p-p / 'i/ '¡"f Taken at plate pin 3, this is the red output waveform, minus Y of course. Blanking pulses 1l pli point negative; they cut off the CRT gun during retrace. The third bar is tallest in the , positive direction, when phase is right. You can see from the waveform which bars on the L screen have some red in them and which have none. The ratio of color-bar signal amplitude to blanking amplitude is important.

V p-p low V p-p high zero ,,fir Rl 4 pen VSO 1 V1 dead f i .t ..tl i

18V p -p 8V p -p 15V p -p 100V p -p 225V p -p R5 shorted R1 low R8 open R5 low fill open L1 open C1 open Cl leaky R14 open R15 open wN

150V p-p 200V p -p 65V p -p R14 open L2 open C5 open at blanker

WF6 Normal 120V p -p ;,;V tI Mile Taken at plate pin 2, this is the green output waveform, minus Y of course. The ninth bar is furthest positive, when phase is correct. It drives the green gun to highest output in that bar on the CRT screen. Amplitude of the color signal is small, relative to blanking. The green gun of the CRT doesn't need much drive. The green phosphor is the most efficient one, and less of green is needed anyway to make white.

V p-p low V p-p high V p -p zero y / ...*NI R6 low R14 open V1 dead ! it l e {i'r q, iii r r r f I j 1i. R9 open R15 open r ,w ;' t,;; ,;,' \r 1nr '. C3 leaky 250V p -p 180V p-p 90V p -p 9V p-p C3 shorted 200V fi R4 open R4 high R2 low R14 open L2 open L3 open C4 leaky

104 1,'",1101I ..... r.,-- r.,.. rigor, /y iiy

+i ,t J1 P 50V p -p 200V p -p 100V p -p 10V p -p 60V p-p 20V p-p C6 open R8 open R1 low R6 shorted R14 open R12 open Cl open C3 open at blanker L1 open

WF7 Normal 210V p -p rill, Oh ,)III ,iIll4 Taken at plate pin 1, this is the blue waveform, 11lwit output minus Y. Blanking is negative, as 1 i in the other output waveforms. The sixth positive bar is tallest, and drives the blue gun i the hardest for i that bar on the CRT screen. You can judge the relative amounts of blue in 6 ¡, other bars on the screen from how tall the other positive bars are in the waveform.

AUGUST 1970 37 WAVEFORMS AS GUIDES

V p -p low V p-p high V p-p zero1 ,1f nt 4n, K,¡.lih l' JI, ....1, R3 low V1 dead ! i"' i ; :

1OV p -p 180V p -p 5V p -p 180V p -p 20V p -p R7 shorted R7 low R14 operi R14 open L2 open C2 open C2 shorted

NaVill! % ß °1/8411 i

240V p -p 12V p p 18V p -p 60V p -p R8 open R10 open R13 open C7 open R9 open

NOTES: about 5 kHz, to show three cycles of the waveform. Use this guide and the Voltages Guide to help you pin Note amplitude. If it's missing, low or high, check the down fault possibilities. parts indicated under those columns. Waveforms are taken with keyed -rain how color -bar gen- Note waveshape. Pay special attention to which bars are erator fed into antenna terminals of receiver. Hue control positive and which negative. Note which is the furthest is centered, color control two -thirds up. negative. With the direct probe of the scope, check the waveforms If there's a change in waveshape from normal, despite at the six points shown. Set the scope sweep at H or amplitude, check the parts indicated.

demodulator. Those are, respectively, red and blue, both The grids are returned to cathode through three 1 -meg- minus the Y signal. which is video or brightness. They are ohm resistors: R5, R6 and R7. Grid bias is largely contact amplified and coupled to the red and blue CRT grids. (Video bias. is fed from other stages to the CRT cathodes). The cathode, common to all three tube sections, isn't re- That leaves green unaccounted for. The G -Y signal is turned to ground directly. It connects to the slider of R14. developed from a phase- shifted version of the R -Y. mixed One end of that potiometer goes to the 20-volt line. The other against the R -Y /B -Y by a common cathode inside the tube. goes directly (or through a decoupling choke) to a blanker Output levels of the color -difference amplifiers aren't all transistor stage. Either end of R14 is thus a form of ground the same. Green is least. because the CRT's green phosphor return. doesn't need as much excitation as do the red and blue. Some All three plates are dc- connected to the CRT grids. The chassis have drive controls between the color- difference ampli- voltage on them therefore partially determines the operating fiers and the CRT grids. They let a technician adjust best gray - point of the CRT guns. So, potentiometer Rl4 can. by setting scale tracking at high brightness levels. average operation of the three tubes, control CRT bias to a The R -Y signal comes through LI from the X demo- limited degree. The dc voltage at cathode pin 7 comes mainly dulator. It is applied by CI to the grid of V1-a. Resistor R5 is from the blanker transistor stage (not shown). the input load. The B -Y signal comes through L2 from the Z demodula- SIGNAL AND CONTROL EFFECTS tor. Capacitor C2 applies it to the grid of V 1 -c. Resistor R7 is Changes in the level of station signal have very little effect the input load for that tube section. on these amplifiers. There are slight variances in dc voltages After amplification in V1-a, some of the R -Y signal is when chroma levels change. fed through a phase -shift network to V I -b. The phase shifthg Varying the color control (back in the chroma section of is done by C4 -L3. Resistor R2 is not meant to be part of the the receiver) does alter the level of color signal in the wave- phase network; it's an impedance -balancing resistor. to match forms. It doesn't affect the overall amplitude of waveforms feedback resistors RI and R3. However, it does have some that have the blanking pulse. That's because blanking has effect on phase. more peak -to -peak amplitude than the color -difference signals. This phase- shifted R -Y sample is fed by C3 to the grid The hue or tint control can change the relative phase in of V1-b. The cathode in V I -b is the same cathode as in V 1 -a color -signal waveforms. Phase is shown by which bars are and VI -c (they're only drawn separate on the schematic). A positive -going and which negative, and which bar in a group is direct mixture of the R -Y and B -Y signals is thus applied to tallest. V I -b by the common -cathode arrangement. They beat against Dc operation of the stages is changed by adjusting the the phase- shifted grid signal and produce a G -Y or green CRT BIAS control (R 14) in the cathode circuit. It also slightly color- difference signal that is amplified by VI-b. changes the overall amplitude of the blanking pulse in wave- Capacitors C5, C6 and C7 couple the red, green and blue forms that include blanking. For troubleshooting, it's best to color -difference signals to the red, green and blue grids of the have the CRT BIAS at midrange. color CRT. However, resistors R11, R12 and R13 maintain dc continuity to the CRT grids from the plates of the tube sec- QUICK TROUBLESHOOTING tions. The values of these resistors and capacitors were chosen Be sure color control is turned about two- thirds up, and carefully, because they exert an equalizer influence on the out- hue is set at midrange. Always use a keyed- rainbow generator put signals. and scope. Dc measurements are helpful in some cases, but A blanking signal is fed to the common cathode through the best clues are in the waveforms. R 14. Amplitude of the blanking pulses depends only slightly In studying the waveforms, watch for several things: (1) on the setting of R14. Note the relative amplitude of color signal vs blanking pulse. The supply connections for plate voltages are simple in (2) Note overall amplitude. (3) Note the shape of the color - these stages. Resistors R8, R9 and RIO are wirewound 3 -watt signal portion of the waveform; it's very important. O Note resistors. They bring dc from the 330 -volt line to the plates. the shape of the blanking pulse, whether it's the natural blank- There is a dc connection from the plates of V 1 -a and V 1- ing that comes with the signal from the demodulators or the c back to the demodulators, through R I and R3. But they added tall pulse you see in the cathode and output waveforms. have little effect on the dc operation of the color- difference Keep in mind that the input of the G -Y amplifier amplifiers. Likewise, the connection to the 20 -volt line is just a (WF3) comes from V1-a. That's why troubles you think handy ground return for phase -shift network C4 -L3 and load should affect only red may also affect green. You track the resistor R4. trouble back to its actual source with your scope. R -E 38 RADIOELECTRONICS 44 MOS IC's make a wristwatch digital clock

A REVOLUTION IN TIMEKEEPING HAS OCCURRED IN THE display of the hours and minutes digits, which is set at past few years. We've seen the appearance of the elec- 1'4 seconds, on command, when the push button on tric watch; then the electronic watch and digital the face of the timepiece is depressed. The same logic clocks -and now a digital wristwatch. circuit supplies a signal that causes the seconds display The newest timepiece is the Hamilton Pulsar, a to light following the minutes display if the pushbutton solid- state, time -indicating wrist computer. It's an all - is held down. A third function of this circuit is to con- electronic timepiece that has no moving parts. Instead trol the setting of the minutes display. Setting the min- it is made up of three major electronic sections: utes, in turn, generates a signal to reset the seconds to 1. A rechargeable 3-cell 4.5-volt battery. zero. thus stopping the display circuits until the time- 2. A high- frequency quartz crystal. piece is restarted. This does not interrupt the accurate 3. A computer module with microminiature logic timekeeping capability of the logic circuits, since the and display circuits. oscillator keeps running. The high -energy main battery, which takes up Another logic substrate, the seconds counter cir- 80% of the total volume of the case, excites a quartz cuit, counts the seconds and allows for zeroing the sec- crystal, which oscillates at 32,768 Hz. This battery also onds display. It also generates the signal that makes the maintains the charge in a similar, but much smaller, minutes display change from 59 to 00 at the proper sustaining battery that continuously drives the logic cir- times. cuitry. The main battery measures a mere 1.035 x 1.4 The minutes counter counts the minutes and gen- x 0.196 inches. erates a signal that causes the hours display to change The computer's integrated circuits, hybrid- circuit from 12 to 1 in a 12- numeral sequence. logic substrates, display substrates and all wiring are The hours circuit counts the hours from 1 to 12. ultrasonically bonded and mounted on separate gold - An automatic light -level control supplies signals plated shim plates of 0.015 -inch thick beryllium cop- to three light sensors that are mounted on the display per. The shim plates with their circuitry are screwed assembly. These sensors measure ambient light levels. together, back -to -back, and form a fixed -program com- As ambient light gets brighter, the sensors lengthen the puter about a tenth of an inch thick. The assembly is duty cycle of the light emitting diodes (LED's) that potted in epoxy for physical protection and cannot be form the numerals, thus giving the effect of increased jarred out of order. brightness to make the numbers easier to read in day- The logic circuitry consists of seven individual hy- light. brid circuits that contain 44 complementary- symmetry The last of the logic circuits is the power switching metal -oxide semiconductor (MOS) integrated circuits. circuit. It supplies power to six display decoders. These They are equivalent to 3,474 npn and pnp transistors. units, one for each digit, are fed the BCD (binary The oscillator and countdown circuit generates the coded decimal) information from the counter circuits primary frequency and divides it down by a factor of and convert these pulses into numbers. two. The 14 -stage divider provides five different fre- The LBD's, measuring 0.021 -inch square, are ar- quencies for various functions, which are fed to other ranged in 27 -dot matrices, one for each numeral. One circuits. of these matrices, however -the tens digit of the hours The operational control circuit times the length of display-needs only seven diodes to form the numeral 1. electronic timepiece on your wrist by LARRY STECKLER MANAGING EDITOR Ifl n n n p sRq, 0111 11 ne n e IIII n

a a.

SEVEN INDIVIDUAL HYBRID CIRCUITS on alumina -oxide substrates (left) make up the logic circuitry inside the Pulsar watch. THE READOUT SUBSTRATES (above) are on a separate module and consist of arrays of gallium- arsenide light- emitting diodes. Also located on this substrate is an automatic light -level circuit that varies the brightness of the readouts according to ambient light conditions. This timepiece has extremely high accuracy, since There is a second battery permanently located inside its basic operating frequency is four times greater than the electronic module that will provide power while the that used in electromechanical quartz- crystal watches. main battery is replaced. This makes it possible to keep time deviation to less One of the most important features of Pulsar is than 3 seconds per month. In addition, since there is that since it has no moving parts, nothing can fail be- no mechanical gear train, the electronic timepiece is not cause of friction or wear. As a further assurance of affected by its physical position. This does have a great durability, all components, including wires, are potted. effect on the accuracy of standard electronic watches. Since there is no conventional stem for winding or set- The three -cell rechargeable battery was specially ting, the stem -sealing problem is totally eliminated, designed and built for this application. Under normal making it relatively easy to waterproof the timepiece. use it will power the Pulsar timepiece for up to six Should it be necessary to reset the time, all the months. The timepiece comes with a spare battery and owner need do is depress one of two marked recesses on recharger. The spent battery is removed by unscrewing the rear of the case. One recess rapidly advances the the back of the case and the fully charged spare is in- hours without disturbing either the minutes or seconds. serted. No accuracy is lost when batteries are changed. The other recess automatically sets the seconds reading

BASIC ELECTRIC WATCH BASIC TRANSISTOR WATCH Power is provided by a miniature battery and is Power is provided by a miniature battery and is transmitted to the balance wheel by electromagnetic transmitted to the balance wheel by electro- impulses initiated by make -and -break contacts, oper- magnetic impulses regulated by a transistor dr- ated by the balance wheel. Accuracy is controlled cuit. Accuracy is regulated by the oscillating rate by the oscillating rate of the balance wheel. Watch of the balance wheel. Watch hands are turned by hands are turned by a gear train which is driven by a gear train driven by oscillation of the balance the oscillation of the balance wheel. The watch will wheel. This differs from the basic electric in that run for the life of the battery. a transistor replaces the mechanical contacts.

HOUR WHEEL

PAWL FINGER FIXED

ACTUATOR INDEX ARM FINGER

ELECTRICAL CONTACTS

HAIRSPRING ELECTRONIC CIRCUIT

BALANCE WHEEL'

40 RADIO-ELECTRONICS SET / RESET FILTER DISPLAY WATCH CASE 2" DIVIDER LOGIC BUTTON

DEMAND SWITCH DISPLAY, OSCILLATOR LIGHT EMITTING DISPLAY SHIM DIODE / TIME RECHARGE- DO LOGIC SHIM ABLE LOGIC CIRCUIT BATTERY D AY/ SCREW, SHIM BATTERY PIN QUARTZ CRYSTAL RESET PIN ELECTRON IC SEAL COVER BLOCK DIAGRAM OF WATCH CIRCUITRY )above) gives a basic picture of how the Pulsar works. The quartz -crystal oscil- CRYSTAL lator delivers a high -frequency signal to the divider. This signal BACK COVER is then processed by the logic circuits, fed through the driver and when the demand switch is depressed, activates the readout. EXPLODED VIEW OF THE WATCH (right) shows how it is put together. Note that the battery takes up the largest amount of the total size of the unit. Then there is a seal over the battery, BATTERY the two IC shims and the case. The total package is about the same size as a modern man's wristwatch. Hamilton reports that a ladies version is not yet available. The smaller size of a ladies watch presents, what are at this time, impossible problems, SCREW, BACK COVER at zero while advancing the minutes. forerunners of the hourglass were being devised. For those readers interested in a brief history of During the Crusades, mechanical time con- telling time, the first recorded instance of time -telling trivances, operated by weights were brought to Europe by measured flow occurred in China over 4,000 years from the East. In 1480, Peter Henlein, a Nuremberg ago. The Emperor, Hwangti, invented a water clock locksmith built a portable, mechanical spring- driven consisting of a pierced brass bowl floating in a basin of timepiece. It had a single hand to tell the hours. The water. Hours were calculated by the amount of time it first wristwatch appeared in 1571. In 1670 a minute took the bowl to submerge. hand was added and in 1685, the balance wheel, a must Later, the Greeks developed and refined the in an accurate watch. Clepsydra (water clock). In other parts of the world, By contrast today we have the Pisar. R -1:

BULOVA ACCUTRON SYSTEM QUARTZ CRYSTAL WATCH Power is provided by a miniature mercury battery Power is provided by a miniature battery. An and is transmitted to the tuning fork by electro- electronic quartz -crystal oscillator delivers high - magnetic impulses, initiated by a sensing coil and frequency electronic impulses to a frequency di- controlled by an electronic circuit. Accuracy is in- vider. Its output drives a motor that drives the herent in the natural vibrating frequency of the watch hands. Accuracy is dependent upon the tuning fork. The watch hands are turned by a gear crystal oscillator's frequency, which is controlled train driven by the tuning fork vibrations. The by the inherent frequency of the quartz crystal. watch will run for the life of the battery. The watch will run for the life of the battery. \v

QUARTZ CRYSTAL PERMANENT MAGNET STANDARD SINGLE -CELL BATTERY

FREQUENCY DIVIDER

TRIGGER PULSE B DRIVE PULSE MAGNET (PHASE SENSITIVE COIL) ELECTRONIC CIRCUIT I OSCILLATOR CIRCUIT 747 AUGUST 1970 41 "CIE training helped pay says Eugene Frost form new of Columbus Ohio

Gene Frost was "stuck" in low -pay TV repair work. Then two co- workers suggested he take a CIE home study course in electronics. Today he's living in a new house, owns two cars and a color TV set, and holds an important technical job at North American Avia- tion. If you'd like to get ahead the way he did, read his inspiring story here.

FYOU LIKE ELECTRONICS-and are paring for better jobs by studying elec- Currently, Mr. Frost reports, he's I trapped in a dull, low- paying job- tronics at home in their spare time. an inspector of major electronic sys- the story of Eugene Frost's success "They were so well satisfied," Mr. tems, checking the work of as many can open your eyes to a good way to Frost relates, "that I decided to try as 18 men. "I don't lift anything get ahead. the course myself." heavier than a pencil," he says. "It's Back in 1957, Gene Frost was He was not disappointed. "The pleasant work and work that I feel is stalled in a low -pay TV repair job. lessons," he declares, "were wonder- important." Before that, he'd driven a cab, re- ful -well presented and easy to under- Changes Standard of Living paired washers, rebuilt electric mo- stand. And I liked the relationship Gene Frost's wife shares his enthusi- tors, and been a furnace salesman. with my instructor. He made notes on asm. "CIE training has changed our He'd turned to TV service work in the work I sent in, giving me a clear standard of living completely," she hopes of a better future -but soon explanation of the areas where I had says. found he was stymied there too. problems. It was even better than tak- "Our new house is just one exam- "I'd had lots of TV training," Frost ing a course in person because I had ple," chimes in Mr. Frost. "We also recalls today, "including numerous plenty of time to read over his com- have a color TV and two good cars schools and a semester of ad- ments." factory Now we Studies at Night instead of one old one. can vanced TV at a college in Dayton. But get out and enjoy life. Last summer even so, I was stuck at $1.50 an hour." "While taking the course from CIE," we took a 5,000 mile trip through the Gene Frost's wife recalls those days Mr. Frost continues, "I kept right on West in our new air -conditioned all too well. "We were living in a with my regular job and studied at Pontiac." rented double," she says, "at $25 a night. After graduating, I went on "No doubt about it," Gene Frost month. And there were no modern with my TV repair work while look- concludes. "My CIE electronics conveniences." ing for an opening where I could put course has really paid off. Every min- "We were driving a six -year -old my new training to use." ute and every dollar I spent on it was car," adds Mr. Frost, "but w'e had no His opportunity wasn't long in worth it." choice. No matter what I did, there coming. With his CIE training, he Why Training is Important seemed to be no way to get ahead." qualified for his 2nd Class FCC Li- cense, and soon afterward passed the Gene Frost has discovered what many Learns of CIE entrance examination at North Amer- others never learn until it is too late: Then one day at the shop, Frost got ican Aviation. "You can imagine how that to get ahead in electronics today, to talking with two fellow workers I felt," says Mr. Frost. "My new job you need to know more than solder- who were taking CIE courses ... pre- paid $228 a month more!" ing connections, testing circuits, and 42 RADIO -ELECTRONICS replacing components. You need to Send for Free Book it we'll include our other helpful really know the fundamentals. Thousands who are advancing their book, "How To Get A Commer- Without such knowledge, you're electronics careers started by reading cial FCC License." Just fill out limited to "thinking with your hands" our famous book, "How To Succeed and mail the attached card. ...learning by taking things apart and In Electronics." It tells of the many If the card is missing, use the putting them back together. You can electronics careers open to men with coupon below. never hope to be anything more than the proper training. And it tells which a serviceman. And in this kind of ENROLL UNDER G.I. BILL courses of study best prepare you for All CIE courses are available under work, your pay will stay low because the work you wart. the new G.I. Bill. If you served on ac- you're competing with every home If you'd like to get ahead the tive duty since January 31, 1955, or handyman and part -time basement way Gene Frost did, let us send are in service now, check box on tinkerer. you this 44 -page book free. With reply card for G.I. Bill information. But for men with training in the fundamentals of electronics, there are Cleveland Institute of Electronics such no limitations. They think with CIE 1776 East 17th Street, Cleveland, Ohio 44114 their heads, not their hands. They're qualified r for assignments that are far Cleveland Institute of Electronics beyond the capacity of the "screw- HEW 1776 East 17th Street, Cleveland, Ohio 44114 driver and pliers" repairman. COLLEGELEVELCAREER Please send me without cost or obligation: The future for trained technicians COURSE FOR MEN WITH 1. Your 44 -page book "How To Succeed In Electronics" PRIOR EXPERIENCE describing the job opportunities in Electrorics today, is bright indeed. Thousands of men and how your courses can prepare me for them. IN ELECTRONICS are desperately needed in virtually 2. Your book on "How To Get A Commercial FCC License." ELECTRONICS ENGI- every field of electronics, from 2 -way I am especially interested in: NEERING ... covers mobile radio to computer testing and steady -state and Electronics Broadcast First Class troubleshooting. And with demands transient network Technology Engineering FCC License theory, solid state Electronic Industrial Electronics like this, salaries have skyrocketed. physics and circuitry Communications Electronics Engineering Many technicians earn $8,000, $10; pulse techniques, 000, $12,000 or more a year. computer logic and Name mathematics through (Please Print) How can get Address you the training you calculus. A college - need to cash in on this booming de- level course for men City State Zip mand? Gene Frost found the answer already working in Electronics. Check here for G.I. Bill information. RE-81 in CIE. And so can you. L Circle 15 on re:uder .cc niee card AUGUST 1970 45 SIMPLICITY AND LOW -COST IC'S MAKE THE cost of constructing a purely all electronic clock quite attractive. The clocks described here have been designed with flexibility in mind. so the reader can select features and price. Electronic clocks are quiet and can be repaired relatively easily. The clocks described in this article use basically the same scheme in the seconds and minutes sections (see Fig. 1). BCD (binary coded decimal) readout is also available. Twelve- and 24 -hour clocks differ in the setting of the time after the first 12 hours. The decoding for a 12 -hour clock requires a few more components since a "one" must be generated so that the clock reads 1:00:00 a.m. or p.m. (See Figs. 2 and 3). The 24 -hour unit resets to zero on the next clock pulse after 23:59:59 while the 12 -hour version resets to I :00:00 on the next clock pulse after 12:59:59. The clock -pulse generator (See Fig. 4) divides the line frequency by 60 or 50 so that the clock will work on 50 or 60 Hz power lines. Five optional features are also provided: 1. Alarm circuit (Fig. 5) 2. Start and stop (Fig. 4) 3. BCD outputs for driving recorders or timed control circuits (Fig. 2) 4. Stopwatch (Fig. 4) 5. Ten minute tone for amateur use (Fig. 7) The alarm circuit functions as in a regular clock; four switches are used to program the alarm. It can be set to the minute. The clock can be zeroed and used as an elasped -time meter. The true BCD outputs are available for driving recorders or printers, or as a master clock to control a series of readouts at other locations.

SOME USES FOR A 24 -HOUR CLOCK

24 hour clocks with BCD outputs BUILD are useful for a number of jobs which in the past have been done by motor driven cams and the like. Some of these uses require additional logic. However, the BCD output provides the Information to control the function shown in the list below. m ultipurpose 1. Used to turn lights on and off at periodic intervals such as: a. When you are away on va- cation to make the prowl- ers think you are home b. To control a Christmas Tree lamp display 1[ [lock 2. Water the lawn Digital 3. Open doors and windows for pets or call them 4. Drive electronic calanders by LEO WALKER 5. Cuckoo clock driver 6. Automatic burglar alarm starter Build the version that fits your needs and budget. 7. Crank up the car in cold weather 8. Feeding periods 12- or 2.1 -hour readout with alarm and 10- minute tinier. 9. Sun lamp timer 10. Sick room medicine caller 11. Control remote readouts Economy clock costs tinder 5100 A digital clock can be used to control a lot of the routine functions at home. In fact, it's quite possible that an electronically controlled job manager could help a lot in some house- holds.

RADIO- ELECTRONICS 46 The clock can be used as a stop- I PPS watch with a maximum time of 12 or 24 minutes. The 60 Hz is applied to the sec- o, SECONDS a MINUTES HOURS o Loa onds input so that readings to ?ítu of a L01 second are available. RESET CIRCUIT I Operation & double boards r-° I hese clock, use Motorola MC780P decade counters, MC97601' decoder drivers, and the Burroughs B5750 readout o6N b tubes. =12

: y The 24 -hour reset operates when - 60 -60 OR RESET the MC724 decoder circuit sees the num- +24 BCD ber "24," pins 8 and 5 go high causing FIG.2 the trigger circuit, a µL914, to reset the J_ SEC MIN FIG.3 hours section to zero. 1BCD The I2 -hour reset is a little more Q > 1 1 2.5PPS RESET 1N914 sophisticated. When the decoder sees the I 914 number a IPPS "13," one -shot multivibrator o o causes the hours section to reset to zero. TIME BASE SWITCH When the hours return to zero. a second 3.9 VCC UNREG 8 3.9V 6.0 one -shot sets "1" in the hours section. =I0 The clock now reads 1:00:00. FIG. 4 i f Even though a full readout is POWER ALARM shown the cost can be reduced by not SUPPLY CIRCUIT reading out the seconds. The approxi- FIG. 4 FIG. 5 mate cost of this version is $95 to $100, 46 ....etRESET CIRCUIT depending on what you have in the junk FIG. 4 box. o -Wr-- 3,9V Double -sided boards are used in 4 -M/r- 3.9V this clock to reduce the number of jumpers required to a minimum. If you plan SHAPER FIG. 4 to make your own boards, I suggest that you make a sample run first. The START ESTOP trick is to make a sandwich out of the two negatives. 60 HZ INPUT FROM P.S. The top and bottom negatives have to register (that is, holes on the top (a) piece must match those on the bottom). The two pieces are then attached to the 85750 B5750 support piece. The material is held in VI V2 place by a piece of tape. The board is /0 9 0 exposed on both sides and then developed as usual. / I READ 2 OUT 2 Registration is most important so TUBE check your sandwich closely while mak- 3 4 5 4 ing the jig. Check the IC pads to make sure that they register. A few practice runs should be made before the final board is made. Double - 9 5 10 4 II 3 12 2 13 I OE 9 5 10 4 II OF sided boards are tricky, but with some practice a first class job is possible. 16 16 MC 9760 P 3.9V 3.9V There are a few precautions for MC9760P those unfamiliar with the double -sided 6 7 15 14 _113 6 15 14 hoards used in this unit. Double check µL9I4's ° o i the board for shorts that may have got- 7 6 7 6 7 6 7 ten through inspection. Use a sharp ra- 810C 13.9V r 0 8 , zor -blade knife to clean the board be- nn, 3.9V tween the circuits. Use a scriber on the a n I+3.9V I area between the lines. Some of the La - 2 2 2 3 2 = leads to the packages must be soldered [0 3 14 on the top and bottom. Only those leads oA D--. which are "active" should be soldered. A o OB BCD small sharp-tipped, 25 -watt (1/2-inch or o BCD OC smaller tip) iron and low -melting -point 13 10 8 13 10 E solder, preferably the smaller wire -size B C CLOCK 3 T A I 1 type. should be used. If boards are pre - INPUT MC780P MC780P tinned they solder easily. Mount the zL914's (do not cut the leads) first, 12 QA OB 12 6 7_1_ 620 MC780P's and other IC's next and fi- RESET nally the Nixie tubes. Leave about 1/2 inch between the board and the tube base. 60 STAGE USED FOR MINUTES AND SECONDS SECTIONS. Circuit description (b) Fig. 1 -a shows the block diagram FIG. 1-a- DIVIDE -BY -60 STAGE is and Fig. 1 -b wiring diagram of the di- shown in the block diagram. b is a vide -by -sixty stage used -This detailed in the seconds wiring diagram of the divtde -by -60 stage. AUGUST 1970 47 12 HOUR RESET PLUS 1 ABE F MC9760P and minutes portion of the clock. 0 1 1 1 0 3.9 V Counter QA is a divide -by -ten stage 1 0 1 1 O and its output is connected to a divide - 2 1 0 1 0 +170V by -six stage, QB. The MC780P will func- 3 0 0 0 - WHEN 13 IS REACHED tion as divide -by -six stage when set "C" 7 lead (pin 6) is tied to V ( +3.9V) 10 LINES 18K through a 620 -ohm resistor. The two READOUT 15 TO Vcc ATEI units will count for 0 to 59 and the re- 14 3,9 V set. QE and QF are MC9760P decoder drivers and drive readout tubes VI and _L8 V2. 2N3567 Fig. 2 shows the =12 stage. A =10 MC78oP stage (MC780P) drives a MC723P flip - 3.9 V OR 82Oá 2N555I flop. At the end of a 9 count, pin 10 of 11 µL914 (2) ? f 560R the ff goes high and turns on the digit o - "1." The =10 resets to zero (10:00:00). 3 MC723P When the count of 13 is reached, point CLOCK "F" goes high, driving the reset one -shot, 5 which causes the hours +10 and ff to set R 0 zero. When pin 5 of the ff goes high due 9 to the reset action, the second one -shot multivibrator fires and drives the "set 1" input of the =10. The clock now reads MC724P 1:00:00. The time -constant of the second one -shot is approximately twice as long as the reset one shot. This assures that 14 13 reset zero and vet 1 functions occur in 13 14 order. Diodes D1 and D2 direct the re- A 12 set pulses when the clock is being used as a -interval meter L¡. E time or stopwatch. } The 24-hour output section is 12 DI ND2 shown in Fig. 3. Two flip -flops are used 3.9V to indicate "1" and "2" (Example IN914 IN914 I.2K 10:00:00 and 20:00:00). When the MC780 4-10 stage reads "4" and the "2" 1/2µL914 2.2K 1/244 L9I4 flip -flop is on, pin 8 and 5 of the decoder go high, driving the one shot circuit which causes the hours section to reset 2r to zero. (The action is so fast that FIG. 2- DIVIDE -BY -12 STAGE (above) sets clock to "1" when count of "13" is reached. 24:00:00 is not seen). The two IN914 diodes direct the reset pulse when the FIG. 3-24 -HOUR OUTPUT SECTION resets "24" to "00" so quickly it isn't seen. clock is being used as a stopwatch or 170V interval 'timer. The power supply and clock pulse generator are shown in Fig. 4. One -half of a MC724 is used as a shaper. Its output is controlled by the remaining half MC9760P of the package which is wired as a reset 6 flip -flop. This ff is used for the stopwatch 7 function. This ff and the set switch at 60 10 LINES TO READOUT Is pps, makes the clock a time interval me- 2N5551 la ter or stopwatch. capable of measuring 520a time intervals to 1/ of a second. Two MC780P's function as a stage; vari- I/2 -60 MC790P ous outputs from 60 pps to 1 pps are MC78oP o 3.9V ; 520a available for driving the clock. Two re- 3.9V D3 95 o mote connnections are provided for con- _L C5 ° A5 vL914(2) a 11 a B6 trolling the clock as stopwatch. The 13 power supply is adjusted for 3.9 volts by ° °ID1 2 D T MC780P varying R5 a small amount. 5 -3 ID1 - The alarm circuit is shown in Fig. CLOCK L_J 5. Three M C770P decade decoders drive 3 a detector circuit made up of two

B MC724P packages. The input to the ° I 4 alarm circuit are the BCD outputs from A IDI the minutes and hour section of the 1N914 clock. R12 L_J 14 The four switches select the time 1N914 that the alarm is to be energized. When TO RESET the correct count is reached all inputs LINE 2 MC724P from the switches are high. The QD 14 7 6 5 14 3 2K and QF 8 pins drive the reset flip -flop from 2µF pin 8 to ground allowing pulses the tone generator to drive the output 4 transistor and speaker. The time -con- -C- -D- stants of the tone generator have been 9 IO II 12 _ 13 14 48 3.9V 2 selected to give a ragged tone to help RADIO -ELECTRONICS 3.9V 1 /2µL 914 dig you out of the deep slumber! A DI manual reset is available, to turn the T 170 VDC alarm off. If the 24-hour version of this clock RI I50V q S20/C1 is used, the alarm will trigger every 24 FI 50mA = hours so there is no need to turn the 250V alarm power switch off if you get up at D2 the same time or need a timed output. A 1 H - UNREGULATED 6.0 VOLTS TO test lead is available to check all the cir- C =D3 2N5296 ALARM CKT cuitry after the selector switch. F2 p6.3V 01 © 3.9 VOLTS The digital clocks shown here have o REG many possibilities. A complete clock with °'=D4 alarm circuit or a basic clock for R3 R4 15011 around the house viewing or as a pro- 04 02 68n FI AND F2 IN D5 + C4 grammer. Only a few of the uses are LINE PLUG 100µF C2 2N5183 shown. As the price of the IC's used in 117 VAC 5001AF = lov this clock drop (further we hope). this R6 Z IK project should appeal to those of you 60 Hz who would rather wait. The MC780P is currently priced at $3.40 and the MC9760 decoder at $5.55. The B5750 is 1/2 MC724 R7 $6.50 in small quantities. I 3. )l+ The remainder of this article, con- 16 sisting of t.escriptions of some of the Ì 2 C6 add -on circuits and parts -placement draw- ings will appear next month in RADIO - ELECTRONICS. More circuitry appears on SI the next two pages. 60 30 1/2 JUMPER o o PARTS LIST MC724 *PPS START 12 12- and 24 -Hour Digital Clocks 14 14 14 -Z 5 3OPPS 3 13 3 24 No. 12 No. STOP 13 13-5 - 12 Hour Seconds Hour Seconds 12 -a- o R8 65750 6 4 5 3 4 II 4 -101 I 3.9V MC9760P 5 3 5 3 62012 - SECTION 5 +6 --0 5 10 MC780P 5 5 5 5 3.9V 2.5 ML914 11 7 I1 7 6 --o 6 9 1 None I PFS MC79OP _E- 7 o None 1 *OMIT IF STOPWATCH MC723P - ' Q MC724P 1 1 FUNCTION IS ADDED o None 2 MC780P MC780P 20 ,,F R9 2 NF 1 1 ON CHASSIS 62011 IN914 2 2 3.9V 2N5551 2 1 Colons 4 4 4 2 FIG. 4 -POWER SUPPLY and clock -pulse (Neons) generator section, which uses 60 Hz from

Digit "1" None 1 ac line. 620 -2 4 3

2000 ohms 1 1

1000 ohms None 1 FIG. S -ALARM CIRCUIT uses decoded

Circuit board 1 1 hours and minutes signals fed through St-S4 to trigger alarm. Power Supply and 2 µF MC770P Clock Pulse Generator 100K/2W 0A o SI MC780 2 Alarm Circuit I MC724 1 Power transformer 1 MC770P 3 MC724P 2N5296 1 MC724P 3 AS 2N5183 2 2N5551 1 0 3.9V Diodes 5 4 102 Switches 7 `C3 Zener 1 Momentary switch 2 a PLUG 3.9V I e.0 Switches 1 2 µF 1 ON 13 r-^REAR Circuit board 1 10 µF 2 xI) 500 0/25 Vdc 1 2.0K 2 MIN EXTERNAL 20µF /250 Vdc 1 Audio Trans 1 SPEAKER 100 µF 1 Speaker 1 .01 1 Circuit board 1 62oa IN914 SUMMARY OF PRICES -_. .- - --, TEST POINT Circuit MC724P Kit Boards 0202, 3.9V 12 -Hour $145.00 $13.50 14 9 12 2:0 rf) 9270A `1 2N706 12 -Hour Less Seconds 125.00 13.50 OC p53 24 -Hour 145.00 13.50

24 -Hour Less Seconds 125.00 13.50 13 Power and 3.9V Supply Clock MC724P 111>1 Generator (Separate) 35.00 3.00 95 2 Alarm Circuit 38.00 3.00 A5 Walnut Cabinet 30.00 3.9V 12 -Hour Economy $100.00 03 $12.50 CS 12 -Hour Economy 110 Less Seconds 95.00 HOURS 24 -Hour Economy 100.00 12.50 9 24 -Hour Economy Less Seconds 95.00 A6 Kit includes semiconductors IC's Power Trans- FKN3 ee former. etc. No resistors or capacitors 9200 B5750-$6.50 ea. MC780P -$3.50 ea. TEST RESET Order all above parts from Safford Electronics, 1 3.9V SPOT Inc., 427 S. Benbow Rd., Greensboro, N.C. ONOr CENTER OFF MORE CIRCUITRY í1.9V 27401 ALARM SW ON NEXT PAGE AUGUST 1970 49 3.9V /0 /PS RI R2 56K 56K 1. oo0 CI 30pF 12

14 13 OA C2 = 1/4 4 -35pF CAW& MC724P 00o 9

1/4 MC724P 10 QA (e _L MC780P(2) 3.9V 3.9V y q q o l t 1 I °- 1t11` 13 II 10 9 8 13 II 1098 Óó9qó _ 10 =10 4 4 00 1=`14 3.9 VDC 6 VOLTS í-H01 3.9V µL914 1 t 1 1 D 5 100Hz 13 II 10 9 8 OUTPUT R2 R3 _ 3.3K 3.3K 10 3.9V 4 = I/4 CI MC724P 1µF 1/2 OB it L923

MC780P OF FIG. 6- 100 -kHz TIME -BASE GENERATOR PIN 8 provides greater clock y (above). ^ FIG. 7- 10- MINUTE TIMER can be added _L- to basic clock circuits (right). FIG. 8- RESET ECONOMY VERSION of the 12- and 24. OE hour clocks is shown in the circuit below. FIG. I FOIL PATTERN above is the top side of the double -sided board used for the power 8 SEC USE PIN 14 supply and clock -pulse generator. 4 SEC 7 2 SEC 15 I SEC 6

2700 2 3 4 5 2700 2700 2 3 4 5 6 7 8 2700 o

1 1 1 1 2700 2700 2700 1111 TT TT I ° T

8 1 SECONDS J Q MC770P oB ( MC770P OD (SAME SAME T 10 II 12 14 15 16 MC790 AS 9 10 I I 12 131415 16. 9 13 AS MINUTES OA 0 14-1 AND 3.9V 3.9V OB o o 3.9V BCD A BCD o Z Z 6200 3.9V 39V 3.9V 1 A 3.9V

Ñ 13 12 I I K) 9 8 1 4 1 3 1 2 1 1 8 62On 13 )MC780P OA MC780P QC 12 6200 6200 IO 3 34 5 6 7 9 C 3 3 9 J1 1

SET SW RESET PPS V TO MINUTES READ OUT LAMPS 3.9V IPPS 0 I 3.9V 3.9V REG r12 VOLT 3 12 460 PPS MC780P SUPPLY t I SUPPLY 4 1 12 3.9V 13 14 Mr000 13 T_ 10.000MF 7 5 MC724P 9 5 IK 8 9 450 n s ' -RECT+ 8 3.W 6pP` 3.9V 2K 220 AC AC L MC724P - 9 Y QI -- { 620 MC780P e TI 15 n = + ~F ) 6 3 6 2N706 27 11 _1_111 Nth

50 RADIO -ELECTRONICS POWER SUPPLY and clock -pulse generator foil pattern on the left is for bottom side of double -sided board. Printed circuit patterns for 24 -hour clock are below (left). The component side is shown above the interconnection pattern for the bottom of the double -sided board. Directly below are patterns for the alarm circuit. The component side is on top and the bottom side of the board is below. All patterns are actual size. Diagrams for parts locations cannot be shown until next month due to space limitations.

CT 0 o 0ó ó0 0_°1 ó 0 0 0 0

a AUGUST 1970 51 FOR NEW RECHARGEABLE niversal Manganese- Fully charges manganese -alkaline batteries in 16 to 20 hours. CELLS by H. R. MALLORY*

BATTERY CHARGERS DESIGNED SPECIFI- voltage or dc output voltage of the char- During that part of the charge cycle cally to recharge alkaline batteries prop- ger when it is in operation. when the battery voltage is substantially erly may handle only two or four indi- The current -limiting network consists lower than the voltage set on S2, the vidual cells of the three sizes in any pair Of CELL SIZE switch S3, connected to current flowing into the battery through combination -four D's. two C's and two cell -size resistor R8. R9 or RIO and cur- one of the cell -size resistors (R8, R9 or AA's. or two D's, etc. Chargers may not rent- limiting transistor 03. With a fully RIO) develops a voltage which forward - charge three, five or more cells, and re- charged battery, whose voltage is ap- biases Q3. As Q3 conducts, it takes over quire 30-36 hours for a full recharge. proximately equivalent to the voltage set control of biasing Q1 from Q4, thereby This article presents a charger de- on S2, this network will have little or no limiting the current of the charge as designed to charge rechargeable manganese effect on the biasing of Ql. termined by S3's setting. alkaline batteries in 16 -20 hours. Parts are readily available and add up to less than PARTS LIST $20. This universal charger will accom- Cl -2- section. 1,0000, 15V electrolytic ca- R12 -100 ohms pacitor (Mallory WP200.1B or equiv) Semiconductors modate batteries of 1 -10 series cells of C2- 1,000 -aF, 1V electrolytic capacitor (Mal- D1- silicon rectifier (Mallory A50) the three available sizes: D, C and AA lory MTAl000F1 or equiv) D2 -20V Zener diode, 10% (Mallory ZA20A (penlight). The charger is adjusted for a Resistors 1W, 10% unless noted or equiv) transistor specific battery by setting the number of RI- 100 -ohm, 1W resistor (or No. 1813 bulb) Q1-2N5035 (RCA) or 40513 R2 -100 -ohm linear potentiometer (Mallory Q2, Q3, Q4- 2N3704 (TI) (or equiv) cells on one switch and the cell size on MR100T or equiv) Other parts another switch. The charger is both volt- R3, R11-22-ohm resistors, 5% (10 required Sl -spst switch age- limiting for the number of cells and for R3) S2 -1 -pole, 10- position shorting switch (Mal- R4 ohms lory 4M11111 or equiv) size cell. -39 current -limiting for the of the R5 -180 ohms S3 -1 -pole, 3- position nonshorting switch R6-470 ohms (Mallory 3243J or equiv) How the circuit works R7 -6800 ohms T1-25.2V, IA transformer (Chicago Stancor R8 -2 ohms (Mallory 3AE2 wirewound) P6469 or equiv) Referring to Fig. 1, the ac power -line R9 -5 ohms (Mallory 3AE5 wirewound) MISC -6 x 2 x 4 -inch chassis, pilot lamp, ac input is reduced by TI to 25.2 volts, rec- R10-15 ohms (Mallory 3AE15 wirewound) cord, knobs tified by D1 and passed on to the bat- RB SIZE tery by series -pass or regulator transistor _- ,CEL S Ql. This transistor is insulated from, and heat -sinked to, the chassis. Cell -size DI R9 oD Qt resistors R8. R9 and RIO are also in A50 551 C series with the battery. Their function S3 will be described later. RIO °AA The voltage -limiting network consists --MVV-1551 of 20 -volt Zener diode D2, resistor R1 SIOFF 03 (or 1813 bulb), variable resistor R2 and ON S2. which is attached to voltage divider +IE Ó04 C2 R3 (10 resistors). Resistors R4 and R5. I 2W 1000µF in parallel with single -cell resistor R3, 117 RII VAC R12 2251, IV compensate the single -cell position of R3 R2 for the base -emitter drop of Q4. 1004 04 -Cl-a Potentiometer R2 is used to adjust the I000µF network for 17.0 -17.5 volts in the 10- 25.2V I5V cell position. Darlington-connected tran- IA - sistor Q2 amplifies the base- current NO. OF CELLS °S2 drive requirements of Q1, and because of R7 would normally bias Q1 to satura- 10 9 8 °7 tion. Voltage -limiting transistor Q4 is al- CI=b ways in saturation and limits the biasing 1000µ v I5V of Q1, and consequently, the output D2 R3 voltage to whatever voltage (less the 20V 22011 emitter -base drop) its emitter is receiv- TB ZENER (TEN 224,1/2W, 5%) ing from NUMBER OF CELLS switch S2. ZA20A The base of Q4 is connected to the positive terminal of the battery through 01- 2N5035 OR 40513 R12, so it is always sensing the battery ON HEATSINK 02,3,4-2N3704 OR EQUAL Labora- Manager. Battery- Powered Equipment while 52 sets voltage on cells. tory. Mallory Battery Co. FIG. 1- SWITCH 53 SETS CURRENT -LIMITING action, 52 RADIO-ELECTRONICS Alkaline Battery Charger Takes 1 to 10 -cell batteries ... rnlla:4e and current lin)itin,

Electrolytic capacitors CI and C2 1.70 -1.75 volts per cell and the charge chassis. Transistors Q2, Q3 and Q4 and provide proper circuit filtering so that current is limited to approximately 160 their associated resistors are connected the voltage- and current -limiting action mA for the D cell, 80 mA for the C cell to the unused terminals of SI. This can covers the voltage range of 1 -IO cells and 27 mA for the AA penlight cell. be done only if SI is a nonshorting type. and the three cell sizes. The volt- One of the mounting ears of R2 is used age- current characteristics of this char- Assembly and use to anchor this part to the pilot-light ger are plotted for one cell and 10 cells The underside of the charger is socket by soldering. Capacitor CI is in- in Fig. 2. shown in the photos. Transistor Q1 is sulated from the chassis with a bakelite For this 16 -20 -hour overnight char- heat -sinked to, and insulated from, the mounting plate. ger, the charger voltage is limited to chassis by bolting it to the back of the After the charger has been assembled, place S2 in the 10 -cell position, S3 in D position, and connect an accurate dc voltmeter 1.8 18 to the output leads. Poten- tiometer R2 is adjusted slowly until a mommum...... voltage of 17.2 to 17.3 is obtained. The 1.7 17 charger is turned off after each test operation, and the voltage at the various 1.6 16 3111 LIIII S2 1 . positions is checked on the voltmeter. C The voltages should be approximate 1.5 J 15 N J % y multiples of 1.70 -1.75 volts per cell. Q1 Substitute a good partially discharged cWi . V 1.4 14 N Z ND1D G battery of either D- or C -size cells for DID the voltmeter. With S2 set for the 1.3 IW- 13 in proper number of cells in the battery, the current -limiting action can be 12 I 1.2 checked with an accurate dc milliamme- ter in series with one of the battery 1.1 II FIG. 2- CHARG- leads. The ER'S voltage -cur- current should be within rent characteristics 20-40 mA in the AA position. 60-100 1.0 IO for various bat- mA in the C position and 120 -200 mA 20 40 60 80 100 120 140 I60160 180 200 is shown for in the D position. If the above perform- DC mA 1 and 10 cells. ance is not obtained. recheck the wiring and the value of all components. especially the connections to all transistors. Although the circuit is short- circuit- proof. to protect the transistors from ab- normal current surges. make connections to the battery and adjust both switches with the charger turned off. The charger will fully charge any rechargeable manganese alkaline battery in 16 -20 hours and will protect the battery from over- charge. Remove the battery from the charger when the charge cycle is completed since there is an approximately 60 -mA discharge path through R I2. Q4 TOP VIEW OF CHASSIS shows layout of and R3. switches, Cl and Tl on the prototype. To obtain maximum battery cycle life. do not overly discharge the battery. Remove the battery from the load and charge it when the battery voltage ap- BOTTOM VIEW (above) shows positioning proaches 1.1 volts per cell. or when the of QI on chassis back for good heatsinking. flashlight starts to dim, the motor starts to slow down. etc. Properly used and charged, rechargeable manganese alkaline batteries will provide many useful SWITCH SI is used to mount Q2 -Q0. 52 discharge -charge cycles. R -E has 10 resistors for R10 (view on left). AUGUST 1970 53 any electric clock and has some disadvantages such as higher cost, difficulty of setting, and most seriously the com- DIGITAL plete loss of all time with even the slightest interruption of power. This problem can be overcome by using rechargeable batteries to operate the clock, and a CLOCK charger floating to keep the batteries charged. The unit draws a total of approximately 500 mA at 5 volts for the counters and the clock, and approximately 20 mA at 170 volts for the UPDATE readout. It is not necessary to furnish 170 volts on the readout as any power by LINDSEY G. RIDDLE* different readout tubes this section of interruption would not change the tim- the board will have to be modified. ing of the clock. The tubes would not SINCE THE ARTICLE BY ED LORD ON IC DI- Readout tubes are beginning to show up light during the interruption. gital clocks was published in the Sep- in the bargain ads, so with this type of It would be an easy matter to con- tember. 1969, issue of RADIO -ELEC- arrangement it will be possible to use struct an inverter from 5 volts to 170 TRONICS I have been building and any type that draws about 3 mA. The volts if one wanted the readouts on dur- rebuilding from his idea. This article seven -segment type will not work in this ing power interruptions. The Inter- passes on some of my experience and circuit. as they require a different national Crystal 0E -10 has an accuracy additions that have been made to his switching configuration to make the in- of .0005 %. If one wanted even more ac- construction article. dividual numbers. Nixie -type readouts curacy a type 0E -30 of .0002: is avail- Much effort has been made to sim- require only one switch to close to make able at a higher price. A chart comes plify the construction and lessen the any number. with each crystal showing the change of chances of error. Two printed circuit The one big change that has been frequency versus temperature changes. boards have been designed to accom- made is that the pulses are derived from For example, from +60° to -10° Cen- plish this. On one. the leads from the a 10 -MHz crystal instead of the 60 -Hz tigrade the frequency changes from readout drivers (SN7441N) are termi- line. A digital clock operating from a seven cycles low to nine cycles high. At nated with numbers so they can be eas- line source is not more accurate than normal room temperatures the fre- ily connected to the proper leads of any readout tubes. This flexibility .111-1 gives in I Op 2N3646 designing and mounting the display tubes 0.--. 170 VOLTS + in different mechanical setups. The tubes .. -IK.0- o come in sizes ranging from th" to 2 ". z iáÇ OO x D 2N3440 The readouts are mounted on the 0 other board. The tubes used are the Na- g o O tional or Burroughs 5750. If you use 00000 -00 O 2N3440 000000 President Engineering. WDSU O O -TV, New Or- sl O - o leans, La. 70130. A,-K-..8040 ° 000000 00° ---27K-- PARTS LIST ,;Or-o (2,-0 Oo, Power Supply 0z- - .' 0--o 000*0 C1- 20 -pF, 250V electrolytic capacitor 42-0 000000 C2- 3,000 -pF, 15V electrolytic capacitor O e Nu'O,nv C3-200-AF, 6V electrolytic capacitor O POTO I O---o C4- 250 -pF, 15V electrolytic capacitor o 00 00 R1- 470,000 -ohm, 1W resistor 0 00 00 N R2, R3- 330 -ohm, 7/2 W resistor D1, D2 -amp, 600V diode (Motorola 1N4005) -1 u< D3 -1.5 -amp, 100V rectifier (Motorola FW100 or equiv) D4 -1 -amp, 50V rectifier (Motorola HEP175 or ---27K-- equiv) o o 1- 2N4910 transistor (with Motorola mount- 00000 ing kit MK25) o00p00 Z1 -5.6 -volt, 1W Zener diode 0 2,, Z2 -9.1 -volt, 1W Zener diode (HEP104) T1- transformer (Stancor PS8416, see text) MISC-Elmenco fuse plug, 1 -amp fuse (2). 6 -lug terminal strip, No. 32 enameled óti Ose o wire, line cord 000000 TWO -SECTION PC BOARD is actual size. Power supply can be into built Mini -box. ° 17SV. > < 1 o

°TO °..0 ñ a 0 o 00000 - 000000 o ---27K- L,_1 o a Ov o 0 0 060 5P 000000 j O..0 o-e - P dXV-oO OwoO o INO C

54 RADIO -ELECTRONICS PARTS LIST Clcck Unit 1- 0.1 -pF, 100V capacitor 1- .02 -pF, 100V capacitor 1- .02µF, 600V capacitor All resistors 1/z W, 10% 1 -5,100 ohms 2- 20.000 ohms 2 -1,000 ohms 1- 10,000 ohms 1 -2,200 ohms 6- 27,000 ohms 5- SN744IN integrated circuit. National Semi- conductor (NS) or Texas Instruments 12-SN7490N (NS or TI) 1-SN7470N (TI) 1 -7402N (TI) 'BUILT -IN' line -cord power supply Ileft). 2 -40346 (RCA) or 2N3440 transistor Above view shows neat layout using decal. 1- 2N3646 transistor 3 -1N191 diode 1 -10 -MHz crystal (International OE-10) quency varies very little. To calculate ahead of the actual time and then 6 -Nixie tubes with sockets (Burroughs) or accuracy. figure stopped, using switch position #1. There National 5750. Or Raytheon socket No. the that it takes 10.000,- so CK1829 and tube CK8754 000 cycles to produce I pulse per sec- is no pulse on this position the clock 1-1-to-5-position switch (Alto MRA- 1 -10S) ond. Then if the crystal were off one stops. 1 -spdt miniature pushbutton switch (Littel way by one cycle all the time. it would A few seconds before the actual time Switch No. 203 or Switchcraft 953SW) has arrived the reset button should be MISC -12 14 -pin in -line IC sockets, 5 16 -pin take 10.000,000 seconds or approxi- in -line IC sockets, 3 transistor sockets mately four months for the time to he pressed and held down. This will cause Note: National Semiconductor IC's can be off one second. the first "Seconds" readout to reset to purchased from Hall -Mark Electronics RUN zero. and the clock will not run when Corp., 8000 Westglen, P.O. Box 36739, The purpose of the switch is to Houston, Texas 77042 or Sterling Elec- enable the clock to be speeded up for the reset is depressed. The switch is tronics, 537 S. Claiborne, New Orleans. easy setting. Changing the switch from #2 moved to #2 or RUN. and as the exact La. Texas Instrument IC's from Allied position or RUN to #3 position will make time arrives the reset button is released, Electronics, 100 N. Western Ave., Chi- cago, III. 60680 or Newark Electronics the unit count ten times as fast as nor- permitting the clock to run. Corp.. 500 N. Pulaski Road, Chicago, III. mal. etc. Mechanical switches do not Because of its accuracy. WWV should For 60624. crystal prices write Interna- make a definite contact when first closed he used for the setting. They broadcast tional Crystal Mfg. Co.. Inc., 10 North twenty -four hours daily on 2.5, 5, 10. Lee, Oklahoma City, Okla. 73102. and produce spikes or transients. These Note: A kit (minus the 10 -MHz crystal) is transients cause the readouts to advance 15. and 20 MHz, giving the exact time available from Stafford Electronics, 427 and give false readings. To overcome each five minutes. plus pulses each sec- Benbow Rd.. Greensboro, N. C. 27401 for this, a reset button is included. The ond. With the clock operating in the $245. Circuit board $9.75. Power supply board $2.50. clock should be advanced a few seconds same room as the WWV receiver it is easy to hear the crystal beating against WWV. It is possible to get them exactly together by slowly adjusting the gadder capacitor on the crystal oscillator. Be- fore the clock is set the ac plug should be plugged and unplugged until the readouts are changing exactly with WWV seconds. If this is not done it will be impossible to get the clock counting exactly with WWV. The 10 -MHz crystal puts out a sine wave. This sine wave must be squared some before it will trigger the first decade counter. This is accomplished by using an IC (SN7402) connected in a Schmitt trigger circuit. The SN7409N (continued on page 68) 0 SN7441N SN744IN SN7441N SN744IN SN744IN nZ

i i DIAGRAM above shows divider and counter IC's used. The cut -out decal at left is placed on IC -side of CUT OUT the PC board to aid in i the installation of com- i ponents.

SN7490N SN7490N SN7490N SN7490N SN7490N S N 7470 N

CUT OUT

2 Z á 8 ti Z z z AUGUST 1970 55 NEW PRODUCTS

More information on new products is available from the manufacturers KNIGHT -KIT DEPTH METER, model of items identified by a Reader KG -711, and fish locator has Service number. Use the Reader Service electronic transducer that attaches to Card on page 77 and circle the numbers of the new products on which transom, side or bottom of boat. Sends down cone of ultrasonic waves which return you would like further information. Detach and mail the postage -paid card. as echoes appearing as flashes of light on meter dial. Operates on either 8 "C" batteries or from boat battery. Range up to 200' AM -FM /FM STEREO RECEIVER on hard bot- KIT, AR -29, features all solid -state circuitry with 65 transistors, 42 diodes, and 4 IC's. Frequency response: from 5 to 30,000 Hz with less than 0.25% hanno- nic & IM distortion at any power level. Regulated power supply, Output transistors protected against short -circuit conditions by dissipation -limiting circuit. Pre- built, prealigned FET FM tuner has 1.8 µV sensitivity. Computer- designed, 9-

pole L -C filter gives bandpass selectivity of 70 dB or better, and eliminates i.f. alignment. Features plug -in circuit toms and up to 100' on soft bottoms. hoards. Simplifies checking of circuits vibration in the wind. Improved gamma Frequency: 200 kHz. Rate: 1440 during assembly and after without exten- matching system includes molded gamma soundings per minute. Scope: 5 x 55 sive dismantling. Built-in test circuitry base and connector for greater conven- x 5 ". Transducer: 6h x 2h ". Brass and plastic construction. Plastic ( probes & meter) permit checks at any ience and durability. $46.65. Mosley sun time without external test equipment. Electronics, Inc., Bridgeton, Mo. shade, brass mounting bracket for Button activates "noise muters" to elimi- Circle 33 on reader service card transducer, gimbal mounting bracket nate on- station FM background noise for scope, cables and instructions. and noise bursts that occur between sta- MULTIMETER, Model TE-235, taut - $69.95. Allied Radio Corp., Chicago, tions. Stereo headphone jack provided on band meter suspension. Pushbutton Ill. front panel. $285.00 Heath Co., Benton range and function switches. Expanded Circle 35 on reader service card Harbor, Mich. 49022. scale meter with built -in mirror for par- Circle 31 on reader service card allax correction. Sensitivity: 30K ohms /volt. Ranges: dcV -0-1, 2.5, 10, MINIATURE WELDER, three sapphire welding tips and torch. Torch can solder wires of 1 mil or less up to 16 -gauge steel. Joins steel, platinum, gold, silver, copper,

BATTERY CHARGER, Model BC -16 recharges alkaline rechargable batteries. Accepts pairs of AA, C and /or D cells only. Uses 120 Vac. $8.95 -RCA Elec- tronic Components, Commercial Engi- and other metals. Flame up to 6300 °F. neering, Harrison, New Jersey. at 2 to 4 psi, rate of gas is .23 to 2.54 cfh. Circle 36 on reader service card Tips in 5 sizes.- Instrument Div. Tescom Corp. 2633 S.E. 4th St. Minneapolis, 50, 250, 1000; acV- 0 -2.5, 10, 50, 250. SOLID STATE OSCILLOSCOPE, Minn. DB: -10 to +36. Resistance: 0- 5,000, LBO -501, 5" scope with bandwidth of Circle 32 on reader service card 50K, 500K ohms, 5 meg. Dc current: dc to 10 MHz, triggered sweep range 0-50 AA, 100 mA, 250 mA, 500 mA, 10 from 0.2 µsec /cm to over 0.2 sec /cm, THREE -ELEMENT BEAM ANTENNA A. Size: 83i" x 5'é x 21: é'. Batteries calibrated vertical input, sharp rise -time for CB, the Paragon Beam, m«Icl PA -311, and test leads included. $39.98. Olson calibration square waves, calibrated time features 3 -piece boom and balanced ele- Electronics, Inc., Akron, Ohio. base, special sweep positions for viewing ments with swaged tubing to reduce Circle 34 on reader service card horizontal and vertical TV, vertical sen- 56 RADIO- ELECTRONICS don't miss this opportunity

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' I am interested in: Classroom Study Home Study Facts on GI BTU

Circle 61 on reader service curl AUGUST 1970 57 SPECTRUM PRODUCTS minimal battery drain using only 200 mA. Safety Circuit guards against antenna PRESENTS mismatch, incorrect polarity and overload. $139.95. \Ir. Steve Kappel, Sales HIGH QUALITY POWER AMPLIFIERS Mgr., Courier Communications, 100 Hoffman Place, Hillside, N. J. 07205. AT MANUFACTURERS Circle 38 on reader service card PRICES NEW LINE OF MIKES includes car - dioid and omni -directional models. Both - types. . Mil . dynamic and crystal Available with variable impedance which can be switched from high to low. Equipped --r-..._...- . . _ .!.-,;ür attf FznE Mil Mit , .__ __ UM UPI -t>tt . sitivity of 20 mV p -p /cm. Tilt stand for , . easier viewing. Uses semiconductors, [1e high voltage power supply and dc cou- xi L- -tA Z- Z. , pling. $339.50. Leader Instruments, Long Island City, N.Y. ONE FET AND 7 SILICON TRANSISTORS. Circle 37 on reader service card POWER OUTPUT. 25 watts RMS at 8 ohm load. (35 watts IHF music power) RADIO, Traveller FREQUENCY RESPONSE. --1 DB from 10Hz to 50,- SMALLEST CB II, 000Hz at full RMS output. features illuminated S- meter, greater sen- DISTORTION. Less than one (1) percent. sitivity, public- address capability with THREE INPUT CHANNELS. One megohm FET high volume control, greater image rejection, impedance input, and two (2) low impedance inputs. and plug -in dynamic microphone, true INPUT SENSITIVITY. High impedance .5 volt for full automatic i.f. noise blanker which reduces RMS output. Low impedance .25 volt for full ignition noise from strong incoming sig- RMS output. Low impedance 1.5 volt for full RMS output. TRANSISTORIZED TEMPERATURE SENSOR. Holds idle current at a constant 10 ma. preventing thermal with built -in volume control. Some have damage. DC OPERATING VOLTAGE. 45 Volts. meshed wind screens to suppress feed- DC OPERATING CURRENT. 10 ma. idle. 1 ampere back "pop," booming and breathing at full IHF output. noise. Fanon Electronics, 100 Hoffman OVERALL DIMENSIONS. 4x4x2 inches. Place, Hillside, N. J. 07205. PRICE. $16.50 Circle 39 on reader service card

MINIATURE ELECTROLYTIC CA- o+ -s !'AiL+ PACITOR, Type HNLH, all- welded, polarized, and etched foil construction. Temperature range -80 °C to +110 °C. nals. Built -in noise limiter reduces igni- Voltages from 3 to 150 V. For appli- tion noise during reception of weak cations in communications equipment, signals. Full talk power, instant operation, computers, telemetry, timing circuits,

nil I, CATE YOU CAN Z r ( LA1S1Et í NOW... _. j: (--) ===_ -1=;;ï

243 ZIP CRTS1Al $4,s, AMATEUR FT ORDER CEBIFICATi RURCRAZE II' QI%+ z 9i) -ì, CB HI .cor tA- Z e Amateur, Monitor and 6 TRANSISTOR POWER AMPLIFIER. THE LATEST IN HIGH FIDELITY CIRCUITRY. CRYSTALS POWER OUTPUT. 5 watts at 8 ohm load. 21 CR2211142 FREQUENCY RESPONSE. 20Hz to 25,000Hz. TEURrT-iu Your dealer has a new, - DISTORTION. Less than one (1) percent. W CERTIFICATE fast, direct TWO INPUT CHANNELS. High impedance 250k, and factory ZIP Crystal Purchase Certificate low impedance. .-..- hat enables you to get the Amateur INPUT SENSITIVITY. High impedance .25 volt for full output. Low impedance .5 volt for full out- Controlled Quality Crystals you want put. II mailed direct to you promptly. Ask DC OPERATING VOLTAGE. 12 volts. DC OPERATING CURRENT. 10 ma. idle. 500 nia. at about it. full output. DIMENSIONS. 4x4x1 inches. OVERALL DIVISION OF PRICE. $11.00 two (2) for $20.00 WHITEHALL :. ELECTRONICS CORPORATION SATISFACTION GUARANTEED Texas Crystals PRODUCTS P.O. BOX 2562 SPECTRUM 1000 Crystal Drive Fort Myers, Florida 33901 CULVER CITY, CALIFORNIA 90230 4117 W. Jefferson Blvd. Los Angeles, California 90016 Circle 62 on reader service curd Circle 63 on reader service curd 58 RADIO -ELECTRONICS cessing. Simple arithmetic required. In- cluded are elementary and advanced - ---- stages of play. $6.95- Edmund Scien- FOR THE FINEST - tific Co. 380 Edseorp Bldg. Barrington, AVAILABLE New Jersey. RECEPTION --. Circle 41 on reader service card tt NEW SUPER "T" VHF -FM -COLOR TARGET ANTENNA SERIES

and power supplies. All aluminum construction for minimum capacitor weight. Use where requirements include com- MUSIC AMPLIFIER, UPB WT. Low pactness, light weight, moderate cost, a high or low mike input, separ- high order of dependability, and high distortion, level tone capacitance per unit volume. -CD Elec- ate mike and program controls, V and 70 V voltage tronics, 50 Paris St. Newark, N.J. control. 25 constant output, for paging, 07101. output plus direct background music, business systems. Circle 40 on reader service card University Sound Dept. 72 -19 Box 26105 SUPER ' t',) fVTE4MV5 Oklahoma City, Oklahoma 73126. "COMPUT -A- TUTOR" 71 -259. Fam- - f7iVGCT Circle 42 on reader service card ily game of skill and chance centered ELIMINATE THE NEED around the world of electronic data pro- FOR TWO ANTENNAS. MULTIMETER, model 2795, solid state, has 68 switch- selectable functions The best features of Log -Periodic and Yagi type arrays are combined for measuring 13 ac and dc voltage for outstanding performance in ranges as low as 1 mV full scale, 14 ac Super Target Antennas. New, and dc current ranges as low as 1 AA used for all full scale, 6 low power (IC compatible) tougher aluminum alloy resistance ranges (.9 mW dissipation), 6 elements. Rugged square boom con- capacitance ranges from 1µF to 100 µF, struction. Unique construction fea- 2 temperature ranges, plus 12 output tures reduce installation time. ranges (dB ). Temperature compensated over range of 0° to 50 °C, with rated ac- S & A ELECTRONICS INC. curacy of ±1.0q for both ac and dc. 210 W. Florence Street Toledo, Ohio 43605 Battery operated, transistor amplifier and MOSFET chopper. Features 10 megohm Circle 64 on reader service card

famous DeltAlert Anti -Theft System Adds High-Intensity Sountl To Lìgt!

When you have an intrusion detection system that already SPECIFICATIONS: cuts theft potential 95% by automatically switching on lights, Ultrasonic Frequency: 35 KHZ t] Area Coverage: 15 -30 feet (de- why add sound? Environmental Variance. EV is another way of pending on shape of area) !, saying that Controls: On -Off Switch; Built in Timer; numerous individual and business premises are sub- Variable Sensitivity Control A Output: 110- ject to varying levels of background noise, including cars, trucks, 130V at 5 Amp. A Power Requirements: 110- 130. 60 HzAC A Dimensions: 103/41N x 3Y4í1 x 31/41) A Complete trains and industrial activity... as well as varying levels of out- with 110-130V Drop Cord A Walnut designer finish. side people- traffic. This is why DeltAlert's new audio capability Unit and all parts manufactured in U.S.A. is the answer to Environmental Variance, and why it's your r------answer to total intrusion detection. DPP! DQ11111IPTO lililt Horn sound is high- intensity, and the horn itself can be located away from the sensing unit. There is a ten second delay P.O. Box 1147 RE /Grand Junction, Colo. 81501 to allow authorized entry and access to the horn's on /off switch. Please send me literature immediately. Order your DeltAlert system, complete with horn. You'll see Enclosed is S Ship ppd. Ship C.O.D. how DeltAlert's variable sensitivity control and adjustable timing Please send . _ DeltAlert(s) @ 69.95 ppd. Please send __ DeltHorn(s) @ 24.95 ppd. provides the most advanced sentry Delt. , complete system on the market. unit. ready to 50995 Name Completely use One ppd. monitor and blanket areas fifteen DeltaHorn, to thirty feet. Easy to Complete with Address connect. No built -in delay Only '2495 rewiring necessary. PM- 1 City /State Zip 1 DP 70-a L---_ mows - _--_-- MEE - Circle 65 on reader service card CHEMICAL TOOLS include Blue Stu$, Blue Shower, Tape and Head Spray, Anti - new miniature Static Record Spray, Lemon Oil, Plastic Polish & Cleaner, plus many others. All electronic tillers

HOLD, BEND, CUT ALL FINE WIRES

WITH EASE

CHAIN NOSE AND DIAGONAL CLOSE CUTTING PLIERS are especially designed for use by the service technician and cover all of his input impedance on ac and do ranges chemical needs. -Tech Spray, P.O. Box above 10 volts. Voltage drop of 7 mV at 949, Amarillo, Tex. 79105 101.4A. Overload protected on all ranges Circle 44 on reader service card through a reset-type front panel circuit breaker. Varistor prevents meter move- Write direct to the manufacturers for in- ment overloads. Taut -band suspension formation on items listed below: movement. Has anti -parallax mirror. Single linear scale for all ac /dc voltage and New address for Precision Tuner Service - current measurements. Complete with Precision Tuner Service is adding a fifth Ideal for electronic, radio /TV, elec- to its four established trical service and assembly. Forged test leads, batteries and instruction man- tuner repair plant alloy steel construction. Precision ual, $230.00. Simpson Electric Co., locations. With executive offices on the machined. All have polished heads 5200 W. Kinzie St., Chicago, Ill. 60644. premises, the plant provides a large area and shoulders. Comfortable "Cushion Circle 43 on reader service card for shipping and receiving, and half the Grip" handles and coil spring openers floor is for storage of speed work, reduce hand fatigue. space designated Miniature round and flat nose pliers spare tuners and parts to speed service. is 5233 South Highway also available. POWER The new address 37, Bloomington, Indiana. SUPPLIES SINGLE: PS -61C CAPACITIVE DISCHARGE IGNI- TION, Ramfire, model CD -21, operates a complete Hoe 01 regular DOUBLE: PS -62C TRIPLE: PS -63C with stock coil and breaker point dis- plug and point life -Economical, contin- tributor. Increases pliers and snips, loo uously variable power and delivers hotter spark across larger supplies by BLULYNE. è gap to racing speeds in excess of 10,000 -Modern walnut finished sqr cabinets with beige panels.. -Excellent regulation and ripple characteristics. -Single, dual. and triple units available. -Short circuit protected -electronic current limiting. Short circuit cannot harm unit. -Grounding cord for added safety. -Floating outputs on all units-ground either plus or minus. -Uses include life testing, production line testing, schools, labs, experimentors use, instructors, technicians, engineers, troubleshooting. battery elim- ination, and many more valuable uses. PS-61C Single Unit

Plus or Minus 1 -15 VDC, 0-700 mA. Usable to 1000 mA. --AN, .0"1"-"ft- Ripple: less than 0.005Vrms max. PS -62C Double Unit rpm. Primary voltage rise time less than Same characteristics as Single unit above for EACH Uses silicon of two outputs. one millionth of a second. in Includes long nose pliers with and Two completely independent supplies to be used semiconductors. Offers anti -point bounce any combination. and secondary arcing protection. $49.95. without cutters; diagonal, needle Up to 30 VDC-Up to 2 Amps. nose, chain nose, side cutting, and ARE, P. O. Box 9562, San Jose, PS -63C Triple Unit Inc., other pliers; electronic snips. Variety Calif. 95117. of sizes. All available with "Cushion Same characteristics as Single unit above for EACH Grip" handles. Professional quality. of three outputs. Three completely independent supplies to be used in PROGRAMMED DOOR ALARM any combination. Up to 45 VDC -Up to 3 Amps. SYSTEM, PDAS 450. May be used in All supplies are fully safety designed. single -zone system with one or more de- PS-61C 549.95 tectors and alarm device or in elaborate PS-62C 74.95 PS -63C 99.95 multiple systems using remote annuncia- Write for illustrated literature on this and tors, closed -circuit TV, etc. Features: other BLULYNE products. disconnects any existing alarm system to Blulyne Electronics Corporation enable legitimate entry, predetermines Dept. R. 3 Sand Springs Road entry time. Plessner Electronics Co., 81 Bloomingdale Rd., Hickeville, N. Y. XCELITE, INC., 10 Bank St., Orchard Park, N. Y. 14127 Williamstown, Mass. 01267 In Canada contact Charles W. Pointon, Ltd. 11801. R-E Circle 66 on reader service card Circle 67 on reader service card 60 RADIO -ELECTRONICS NEW NOW LITERATURE - All booklets, catalogs, charts, data CHECK sheets and other literature listed here with a Reader's Service number are free for the asking. Turn to the TRANSISTORS Reader's Service Card facing page 79 and circle the numbers of the items IN OR OUT OF CIRCUIT .. . you want. Then detach and mail the card. No postage required! Flick function Flick function switch to left switch to right to check all to check any CATALOG -.V- ber E -71, Chassis Punches and regular tran- FET. Knockout Punches. Includes various tools for cutting holes in metal, rubber, plastic, etc. All sistors. punches use ordinary hand wrench. Geared toward amateurs and professional craftsmen, these tools save both time and labor.- Greenlee Tool Co., 2136 12th St., Rockford, III. 61101 Circle 45 on reader service card

ELECTRONICS PARTS CATALOG -No. N -71, includes hundreds of products for engineers, technicians, and hobbyists. Lists capacitors (fixed and variable), chemicals, resistors and potenti- ometers, transformers, switches, lamps, fuse holders, test equipment, lab supplies, mikes, speakers, and many other most- wanted supplies. -North American Electronics, 1111 Seminary St., Rockford, Ill. 61108 Circle 46 on reader service card

PANEL METER CATALOG No. D-70. Twenty pages packed with panel meter data. 11/2". 21/ ", 31/2", 41/2", 5',_ ", 61 2 ", 7'-2", & 81/2" models are described. Special units, including edgewise meters, wattmeters, and suspension meters are also included. -Triplett Corporation, Bluffton, Ohio, 45817. R -E Circle 47 on reader service card

Build this magnificent Schober Theatre Organ for only 1730! Includes ewe finished walnut plus console. Amplifer, speaker system, the new Optional accessories LARGE 6" METER extra. Only FIELD EFFECT $1256 If you build your own TRANSISTORS console. too!

You couldn't touch an organ like this In a store for less than 13500 -and there hasn't been a musical Instrument with this vast variety of genuine Theatre You won't be stopped when you run into the new FETs that are wired Organ voices since the days of the silent movies! If into the latest hi -fi, newest TV receivers and nearly new you've dreamed of the grandeur of authentic big -or- every other device gan sound in your own home, you won't find a more coming on the market. For the very first time, you can check them all, satisfying Instrument anywhere -kit or no kit. You can learn to play It. And you can build it, from in or out of circuit. The TF151 works every time using tried and proven Schober Kits, world famous for ease of assembly without the slightest knowledge of electronics or signal injection techniques. New, improved tests en special RF transistors music, for design and parts quality from the ground and the latest high power transistors, mean that the TF151 is the up, and -above all -for the highest praise from only musicians everywhere. up -to -date transistor tester on the market. A new, exclusive setup book Send right now for your copy of the full -color Schober catalog, containing specifications of the five in rear compartment guides you to every test for over 12,000 transistors Schober Organ models, beginning at $499.50, No FETs. is charge, no obligation - but lots of food kit a healthy and The book not needed for general service troubleshooting. musical appetite! Regular transistors are checked for beta gain and Icbo leakage. FETs are checked for transconductance and Igss leakage. only $12950

NEW SENCORE TF17 compact in and out of circuit

Them ZOrgan Corp., Dept. RE -81 transistor FET tester. Same as TF151 except in new 43 West 61st Street, New York, N.Y. 10023 Sencore Handl case and with 4 -1/2' meter. ..$109,50 Please send me Schober Organ Catalog and free 7-inch "sample" record. Enclosed O please find $1.00 for 12-inch LP record of Schober Organ music. NAME ADDRESS ENCORE CITY STATE ZIP NO I MANUFACTURER OF ELECTRONIC MAINTENANCE (OU/PM(N7

426 SOUTH WESTGATE DRIVE, ADDISON, ILLINOIS 60101 Circle 68 on reader service card Circle 69 on reader service card AUGUST 1970 61 COLOR TV CAMERAS fairly compact and features fast setup time -eliminating (continued from page 32) one major drawback of the majority of TV cameras: hours of warmup time and setup adjustments. low -cost color is there once again, but this time working for all three It all adds up to one thing: a truly primary colors. Another major difference: the Sony camera has a separate luminance pickup tube. Some of the special features of the camera include ultra -compactness. The camera head weights 271/2 pounds and horizontal resolution is stated as 450 lines at the center ANOTHER color camera illustrat- in the latest spec sheets. Overall resolution and edge resolu- ing trend toward tion aren't stated, but in eyeball tests, the cameras picture lower cost and complexity is the looks good indeed. VF -7001 by GBC. Another compact entry, this one by Toshiba, is a featherweight at just 10 pounds (without the lens). Like the Sony, this camera has two pickup tubes -one for color and one for luminance. The camera's resolution is stated at 300 lines, and it is designed for the usual noncommercial TV categories. The camera head contains a built -in control unit and rf generator so monitor connection can be made directly via a standard color receiver's antenna terminals.

Other Japanese models camera priced for the hobbyist, experimenter and TV ham Panasonic's newest compact camera uses the standard is still a couple of years away. Bottom of the line right now three pickup tubes with an uncomplicated optical system. is about $5,000, but with developments coming as fast as The tubes are 2/3-inch separate -mesh vidicons and the they are, and the new two -tube Japanese format, two or camera head weighs in at 28 pounds without the lens. Hori- three years may see color cameras breaking the thousand - zontal resolution is given at 400 lines (center of picture) and dollar barrier. After that, prices will continue to tumble; the rack -mountable control unit is minuscule as such units someone will introduce a kit at $500 (less lens), stripped - go. Again, this camera is primarily for CCTV and other down versions without sync boards and viewfinders will hit less- than -broadcast critical performance. the market, and color will at last be here at a bargain price. Other cameras are vying for the low -price champion- But its not here yet. Not quite. R -E ship, but all have three pickup tubes. A Japanese entry distributed by GBC Closed Circuit TV Corporation is PORTABLE VTR'S (continued from page 12

needs of the pickup device (vidicon) and the viewfinder (CRT). Most cameras also mount the microphone; however, only wire connections are provided for the mike and It's yours all audio processing is accomplished in the shoulder pack. Fig. 9 shows a simplified block diagram of the Sony FRE E DVC -2400. Output of the vidicon is amplified to about 2 for the asking!

Si,

GIANT 260 PAGE 1971 RADIO -TV ELECTRON ICS CATALOG YOUR BUYING GUIDE FOR EVERYTHING IN ELECTRONICS! RESERVE YOUR COPY NOW FOR DELIVERY IN LATE AUGUST Write to: BURSTEIN- APPLEBEE CO., DEPT. RE-8, 3199 MERCIER ST., KANSAS CITY, MO. 64111 FIG. 9- SIMPLIFIED BLOCK DIAGRAM for the DVC -2000. [Nam.. volts through a series of low- noise, wide -band amplifiers Address that also compensate for the frequency rolloff that occurs the to the first amplifier. Part City in the coupling from vidicon of the output video is clamped and rectified in the auto- Stale Zip Code matic sensitivity control (ASC) detector to provide a dc voltage proportional to average white level. This dc voltage ( continued on page 71) Circle 70 on reader service card 62 RADIO -ELECTRONICS /ílehow- Yee PIONEERING SOUND IDEAS THRU ELECTRONICS CB Troubleshooter's proudly introduces their new CENTRAL SECURITY CONTROL system Compiled by Casebook Andrew J. Mueller*

Case 1: Radio does not receive. Transmits ok.

Common to: Johnson Messenger 100

-I0V

RI, 2 7K OPEN! RECEIVE I6.8pF OSC

TO MIXER 39 p F ¡--

I I -- I ¡ T° ° T° 4700 6800 .01 ¡ b_-j --180 L____., For economical and secure operation in business, industry or government, IK our remarkable new closed circuit television system offers automatic step to 12 TPF by step picture viewing and selective fixed picture monitor of up video cameras. In addition, we also offer TwoWay voice intercom, door surveillance and monitoring of regular and emergency exits and electric door lock control and release. Write, wire or call today for the answer to your security problems - 1602) 264-1348. Remedy: Replace R1. NELSON -HERSHFIELD ELECTRONICS 1848 WEST CAMPBELL AVENUE PHOENIX, ARIZONA 85015 INVITED) Reasoning: R1 is the bias resistor in the local receive (DEALER INQUIRES oscillator. It has opened, preventing the os- Circle 71 on reader service card cillator from starting when the set is turned restores the radio to normal on. Replacement Designed and manufactured in U.S.A. operation. NEVER Case 2: Radio does not transmit. Receive is ok. A BURNOUT Common to: Lafayette HB -525A IN 6 EMC DIODE- PROTECTED VOMS b i._.-.....-....._ .005 NOBODY ELSE BUT EMC DESIGNS IN SO MUCH VALUE! 2SC55 TO RF Professional quality and versatility Lifetime TRANSMIT (`` DRIVER prote :tion against electrical abuse No meter burn- OSC out, needle damage, or fuse replacement VOLOMETER TO CHANNEL I6pF Mode 109A Factory Wired & Tested $28.95 SW Mode 109AK Easy -to-Assemble Kit $21.15 20,000 t: v DC sens. 10,000 f1 /v AC sens. 41/2 ", 40µa meter. High impact bakelite case. 5 DC 20 voltage ranges: 0 -6 -60- 300 -600- 3000v. 5 AC volt- 6.8 K pF 47 age ranges: 0.12.120.600.1200.3000v. 3 DC current ranges 0- 6.60.600ma. 3 AC current ranges: 680a 100 0- 30- 300ma; 0 -3A. 3 resistance ranges: 0.20K, - pF - 200K,- 20 megs. 5 db ranges: -4 to +67db. With carrying strap. 51/4" W x 63/4" H x 2v/a" D. RFC VOLOMETER Model 103A Factory Wired & Tested $20.75. CB Model 103AK Easy-to- Assemble Kit $16.80 10.2 V 41/2 ", 2% accurate, 800µa D'Arsonval e/É type meter. One zero adjustment for .02 .02 both resistance ranges. High impact PA bakelite case. 5 AC voltage ranges: EMC, 625 Broadway, New York 12, N.Y. 0 -12- 120 -600.1200- 3000v. 5 CC voltage SW STUCK ranges: 0. 6.60. 300 -600- 3000v. 5 db Send me FREE catalog of the complete value -packed EMC line, and name of I * CB /PA SWITCH ON IN PA ranges: -4 to -64db. 5 AC current POSITION ranges: 0- 30.150.600ma. 4 DC current local distributor. SQUELCH CONTROL RE ranges: 0- 6.30- 120ma; 0.1.2A. 2 resist- -8 ance ranges: 0 -1K, 0 -1 meg. 51'a W x NAME 63/4" H s 21a" D. squelch control and switch. Remedy: Replace the POCKET SIZE VOLOMETER ADDRESS Model 102A Reasoning: The PA switch is on the rear of the SQUELCH Factory Wired & Tested $16.95 CITY 20NE_STATE- I control. The switch is defective and stuck open, Model 102ÁK Easy -to- Assemble Kit $14.40 can reach the transmit oscilla- 31/2", 2% accurate 800µa D'Arsonval and no voltage type meter. One zero adj. for both res. tor. As this is all one part, the entire control ranges. High impact bakelite case. 5 AC must be replaced. R -E voltage ranges: 0.12.120- 600.1200-3000v. 5 DC voltage ranges: 0.6.60- 300 -600- EMC 3000v. 3 AC current ranges: 0.30-150 - ELECTRONIC MEASUREMENTS CORP. 625 Broadway, New 12, Service Manager, Tel -Air Communications, Inc.. Pewaukee, Wis. 600ma. 4 DC current ranges: 0-6-30- York New York 130-na; 0 -1.2A. Resistance : 0 -1K, 0-1 Export Pan -Mar Corp , 1270 B'way, N.Y. I !leg. 33/4" W x 61/4" H x 2" D. In the Shop ... With Jack By JACK DARR SERVICE EDITOR

Diddle Adjustments For Color A scope pattern also showed a very plain 60 -Hz bending in the video WE HAD A GE KC COLOR CHASSIS WITH waveforms. So, back to the power some very unusual symptoms. Un- supply. Bridging filter capacitors usual at least according to the diag- didn't help a lot. I remembered a hint nosis made by another technician - I'd made a note of quite a while back. namely, "bad power transformer." It Why not check for an open rectifier had a bright picture, but the reds in the full -wave bridge circuit used were weak. Greens and blues looked here? o.k., or not too bad anyhow. The Checking the rectifiers showed color -bar pattern had a distinct weave that this was indeed the case. The in it. It was supposed to have had a clod who had "worked" on this first past history of circuit- breaker trouble, had replaced a rectifier, but forgot too. But the wattmeter didn't show one minor detail: one end wasn't sol- anything unusual -in fact, it was dered. This cleaned up the hum prob- drawing a little less than the rated lem, and I got back the 50 volts I'd wattage. lost in my 400 volts B+. If you can't and you don't Well, let's see. Take the easy one The color bars still looked funny. see the hear the first. Ripple in the power supply? Yes, Reds still weak, smearing still present. difference difference- indeed. The scope showed about We had dc voltages all around the 15 -18 volts p-p ripple on the 400 - demodulators, and the color difference volt B+ line. Hmmm. While I was at amplifiers, etc. were balanced. A Vec- it, I probed around the CRT grids. torscope pattern looked quite a bit The rocker patterns there were very healthier, but was still a little bug -ea- badly smeared. I couldn't even see the ten on the red side. The petals were vertical lines of the color bars. The cleaner, though, since the ripple had screen showed the same kind of been removed. smearing. The Vectorscope pattern Well, if he makes bad solder had to be seen to be believed. It joints, maybe he's also a "diddle stick looked like a dwarf chrysanthemum artist ". Using the Vectorscope pattern with the Dutch Elm disease or some- to touch up the alignment of the thing equally gruesome. demodulator transformers helped a

VIDICON TELEVISION the long- lasting CAMERA FAIRCHILD/ DUMONT TV Ultra compact quality will CAMERA HEAD head. Approx. Self- contained 23/e dia. x 12" L tell you- Video Amplifier. Make your own (Requires separate surveillance, pipe camera control) liSits;" /t inspection, portable closed IT'S A Stock #6560 system QUAM! Less Vidicon & Lens circuit around this head. Use any std. Model TC 200 1" Vidicon and With schematic. The Quality line "C" mount lens ONLY $49.95 plus postage & insurance Wt. 4 lbs. for every speaker need Terrific bargains in TV cameras, lenses, monitors, tripods & all CCTV Accessories in our Giant 25th Anniversary Catalog QUAM 970S1 (Available Sept.) Write for free copy. Quam -Nichols Company DENSON ELECTRONICS CORPORATION 234 East Marquette Road 203/875-5198 Chicago, Illinois 60637 Phone: (312) HU -8 -5800 Box 85, Longview Street Rockville, Connecticut 06066

ircle 72 on reader .+orrice carel Circle 73 un reader .u'rrice Card 64 RADIO -ELECTRONICS lot. My flower now shaped up a lot fairly straight. -J. B., Flint, Mich. better, but it was too small. Did he From the picture, this looks very get the bandpass transformers, too? much like "top pincushion" trouble. He did. Touching up the bandpass Service In this chassis, there is a corrector transformers for maximum length tube, V 11 on the Zenith diagram, a (amplitude) of the petals brought the 6KT8. I'd try a new tube first. If this color up on the CRT. Clinic does not correct it, run the pincushion Now, there was only one little adjustment. thing left. The whole thing, color -bar by JACK DARR Put a crosshatch pattern on the SERVICE EDITOR pattern or color picture, had that screen, and adjust the "roP PIN indefinable "I -just- don't- look -quite- Top Droop PHASE" control until the line straight- right" look to it. So, I hooked up the I've got a decided curve in the ens out. If this control has no effect, sweep generator and scope and took a horizontal lines at the top of the check the waveforms in the pin -cor- look at the i.f. alignment curve. I screen in a Zenith 20X/C38 color TV rector circuit. Look for the character- knew he couldn't keep his cotton - chassis. Rolling the blanking bar istic "bow -tie" waveform on the triode pickin' hands out of the i.f., too. The down the picture shores something plate of the 6KT8. There will be no dc curve looked something like Fig. 1 -a. like the sketch. The bottom part is oltage on the cathode, but the red-

45 MHz Try these installations with

42.17 MHz 47MH any other five watt unit!

O Notice the sharp peak at 45 MHz. and the low amplitude of the color subcarrier at 42.17 MHz. This was making the color a little bit weak! Touching up the appropriate i.f. transformers helped the shape of the curve a lot, but I couldn't get the color subcarrier marker up off the floor. After a good hit of head scratching, I uncovered the reason. The 41.25-MHz sound trap does not belong over in that part of the curve! If its mistuned that much, it will suck the color carrier right out of the curve. Moving it back where it be- longs left the curve looking more like Fig. I -h.

42.75 MHz 85% 215% 45MH14 2% 85% _lo MAX SAG i 42.17 MHz 60 %210% 4575 MHz 41.65 MHz SET TO 50% At $9995 the Messenger 125 fits anywhere MIN 25% 47 25 MHz 41.25 MHz 3V PP ...including your budget. RESPONSE "5" Best of all, even with its mini -size and price, the Messenger b 125 is big on performance. Its 5 -watt transmitter, with high Correct tuning of this trap will level class B modulation and speech compression, gives it all do a lot to keep the worms out of the the "talk power" you'd expect from a full -size radio. Half -a- Dimensions: 1'/,s" H igh x 4'% Wide x 7" Deep color in an otherwise fairly good microvolt receiver sensitivity pulls in the weak ones. Auto- 4 -watts output at 13.8 VDCFCC color picture. If the set tunes all right. matic threshold noise limiting, IF clipping, and special AGC type accepted, but the color drops out as soon as circuitry means less noise -better quieting. Full 2 -watt audio DOC approved All solid state lets you hear even in noisy vehicles. And the Messenger 125 draws just 0.2 amperes on you tune it out of the worms, look at looks great, too. Not a single knob -pushbuttons select up to squelched stand -by Optional this sound trap. If it is only a tiny bit 5 channels, slide -levers adjust squelch and volume. Installs portable pack available with re- mistuned, it can get over into the 42- between bucket seats, in door pockets, on trail bikes -or chargeable battery, charger, an- MHz region and chew the heck out your with its optional rechargeable battery pack. tenna, and leather carrying case of the color carrier. over shoulder A careful, scientific diddler can make this adjustment in the home with the well -calibrated eyeball, if the E. F. JOHNSON CO. only trouble symptom is too many WASECA, MINN. 56093 worms in the color areas. R -E Circle 74 00 reader service card AUGUST 1970 65 green wire goes back to the vertical got the same trouble. However, I ouput transformer and should have rather doubt it. Voice coils in the tre- a 90 -volt p -p vertical spike on it. If mendously high powered speakers used on modern guitar amplifiers very likely have a heavy aluminum ribbon voice coil which wouldn't be apt to make this kind of "whish" noise. In- VERT BLANKING BAR cidentally, you're not about to dissolve that cement on these speakers. It's probably epoxy or something equally durable! Take the speakers out of the enclosures to eliminate the chance of loose pieces in there. Set them on the J bench and feed an audio signal gener- these waveforms are missing or dis- ator into the input. Now, start at a torted, check the pin- transformer and very low frequency and vary the fre- the capacitors and resistors. There are quency upward until you hear the only a few parts in this circuit, so it noise. A single tone signal will often shouldn't take long. show up this type of noise if it is Fill in coupon for a FREE One Year Sul1 really a loose part. etc. If you hear the scription to OLSON ELECTRONICS Fantas- tic Value Packed Catalog - Unheard of Noises In Guitar Amplifier same noise now, it is definitely in the LOW, LOW PRICES on Brand Name Speak- speakers. ers, Changers, Tubes, Tools, Stereo Amps, Speakers Tuners, CB, Hi -Fi's, and thousands of other There is a funny noise in the Due to the construction of these Electronic Values. Credit plan available. speakers of this high -pottered guitar heavy -duty speakers, you'll probably NAME amplifier. It sounds something like a have to send them back to the factory ADDRESS_- rattlesnake or a high- pitched hiss. I for repair. They're the only ones who CITY STATE suspected the voice coils, and tried to can get them apart and put them back GIVE ZIP CODE take o$ the aluminum dust -corer to together properly!

If you have a friend interested in electronics check, but I couldn't find anything send his name and address for a FREE sub- would dissolve it. What do you scription also. that Blue Cellophane Picture think ? -D. K., Lompoc, Calif. Whets this RCA CTC38 is first OLSON ELECTRONICS We used to have this kind of turned on, the picture is normal, but Dept. LH 260 S. Forge Street in small speakers, when the has a bluish cast as if you were look- Akron, Ohio 44308 noise last couple of turns on the voice -coils ing at it through blue cellophane. If Circle 75 can reader service tarsi came loose. It is possible that you've you fiddle with the fine tuning, you OUTSTANDING VALUES FREE $1 BUY WITH EVERY 10 YOU ORDER tt °0 "'5,`'°B;;5 FREE GIFT WITH EVERY ORDER 12- MINIATURE ELECTROLYTIC 300 - ASST. V2 W RESISTORS KNOB SPECIAL CONDENSERS For r r K S1 SARKES TARZIAN TUNER Top Ilrand. Short Leads, Excellent Si miniature .Durk Selection - ASSORTED RADIO 100KNOBS All ,tnnda,.l types Si 10 - MINIATURE 456KC IF 41mc 100 -ASST 1/4 WATT RESISTORS S1 82(1 value o TRANSFORMERS Exeepti.'nal Value S1 stand. chulee ohmage., same In V -pc -t:, x tî. 50 - TV KNOBS - POPULAR Si Latest Compact 100 -ASST 1/2 WATT RESISTORS Sl F.'r most Sets FOCUS stand. choice olin,agea. sume in 5r- TYPES HEAVY DUTY COLOR Model good for 25 VERTICAL LINEARITY RECTIFIER 14.001) rn' ( 1 ma S1 - 1 Long .h,lnk Front all 41 me TV's. 70 - ASST WATT RESISTORS 51 KNOBS 51 50 OIL IMPREGNATED stand. choice ohmage,. some in 5,, 111tInt . . miniature a.,,,rlmer - rocs TUBULAR CAPACITORS BRAND NEW- 35 - ASST 2 WATT RESISTORS S1 30 - VERTICAL LINEARITY ecIain. .Axing Lead, -Most 53.25 stand. choice ..hn)ages. some In 5, L. KNOBS Side Im,unt Si popular Value. Sumd:n.l .12es 50 - PRECISION RESISTORS 51 COLOR -TV RECTIFIER - asst. list price 850 less 95C' 25ñKNURLED RADIO .KNOBS Si most color Sets- _I:SO" 51.95 U-1,1 in 20 ASSORTED WIREWOUND kV 3 101. - Si 25 ASSORTED CLOCK -RADIO RESISTORS, 5. 111. 20 swan 15 ASST. ROTARY SWITCHES KNOBS "" n Si - $1 Best - S - TOGGLE SWITCHES S1 aI popular type, Ken do, TUNER " SARKES TAR SeST. srl-r. Drsr. DPDT ZIAN" ever made -last word for 6 KITS FOR SS 15 - G.E. #NE -2 TUBES S1 ASSORTED SLIDE SWITCHES ANY 71 Neon Glow Lamp for tat stability. definition A smoothness 10- Si of operation. An opportunity -to 1_1 SPST. SPIT. IPIT, etc. 150' - BUSS WIRE , ' " ^' S1 II,,f type . improve STEREO HEADPHONES fo hookup.. .pt/..,.. and bring your TV Re- RADIO 51.50 . . . m p 111 FI quality CompleteC o 55.95 ceiver up -t -date. $795 Li go,sl.good. bad. to okell. as -Is. potluck sw ell Stereo plug 50 .0033 DISC CERAMIC S1 - COMPLETE with Tubes TAPE RECORDER-..''''.."'d Iyl. CAPACITORS C.H I 54 TUBE CARTONS (colored) I. u, had. Kruken. 11.-1,. potluck 50 - S1 2 assorted .Ire, fur Popular rune, . 3- ELECTROLYTIC CONDENSERS S1 - COLORBURST QUARTZ - most popular m,mrl'l' 511 ,31) -150, CRYSTAL REPLACEMENT Fr $20 - SHURE M7D DIAMOND 53 4 36" Hi -Fi CABLES 1c Á most Color TV Sel,..3370.545 NEEDLE e ael reldaeemem - une end 7 - TV ELECTROLYTIC CON- Si 51.49 Monied /hune plut; at EC SHUREM44SERIESDIAMOND stripped and tinned leads on other Si DENSERS SÁ.69 asst. all new NEEDLE exact nepineea,ent . Li end 5 - 6' LINE CORDS S1 TV TUNER - Si IJ #18 I ..i ,er Wire standalxl makes. Less lutes COLOR POWER TRANSFORMER `lare IICA 51.19 JUMPER CABLES MOTOROLA PWR TRANSFORM - Cool for m ".t .et. 21111150 SC.95 Type Mug un Iluth Ends. 2 For Si G.E. STANDARD TUNER List Price-536.75 v 3' 110v, Model rota- sax2u2, . . . (Er- 56.95 50 - ASST. TERMINAL STRIPS $1 sux2lr3 all type,. 1.11.1g to 6lux 25 - #130 WESTINGHOUSE PI- 6 - TRANSISTOR RADIO EAR- 51 nom.. ...,Imo 51 PIECES ,Vire. elete with plug OF EQUIPMENT 11/ LOT BULBS WESTINGHOUSE STANDARD 2 -G.E. PIECES . shekel with over 200 useful parts S1 as #.17 TUNER tir..., . m . k 5. 100' - FINEST NYLON DIAL 51 n4C81 l,55 - . . 25- WESTINGHOUSE PILOT CORD best slae. .028 gauge MOTOROLA HEP KIT -INTE- your choice or #154 BULBS #24I. 51 UHF TUNER - TRANSISTOR 53.95 10 SETS PHONO PLUGS L GRATED CIRCUITS INCLUDES #19t23 .,u - Si -une J-K nip flop. une Dual TYPE C.t,l TV sets PIN JACKS WA tspe Two ul,ner. One .1 -input Gate. 53.95 3- ELECTROLYTIC CONDENSERS S1 50 - ASSORTED PRINTED CIR- $1, 3- PRINTED CIRCUIT IF TRANS- 51 ('.ales. All taire C.D. 500 mfd -2011 volts Dual 2.111put CUIT SOCKETS ' 'type, FORMERS 4-Lug. 450 KC Cost of DELIVERY . . . Scientific light packing for safe delivery at minimum cost. IMMEDIATE goods HANDY WAY TO ORDER: Pencil mark or write amounts wanted in each box, place letter A,LIre., shipping add esti,natel F in box for Free $1 BUY. Enclose with check or money order, extra for shipping. TOTAL Tearsheets will be returned as packing slips in your order, plus lists of new offers. Minimum Order $3.00 Please specify refund on shipping overpayment desired: CHECK POSTAGE STAMPS MERCHANDISE (our choice) with advantage to customer BROOKS RADIO & TV CORP., 487 Columbus Ave., New York, N. Y. 10024 2TELÉPH 5600 Now, industry's most effective cleaning can get the color to flash in mid out. terminal strip on the upper back part tool is available to you, too. Precision - After about 30 minutes it starts to of the chassis. You may have a bro- cleans hundreds of things you couldn't work and keeps on. What is causing ken wire here, or an intermittent sol- clean before. High frequency sound this? -F.B., Livingston, Mont. der joint, etc., due to pulling the waves scrub tiny grooves, threads, joints, I've heard of slow -starting os- chassis in and out. If the grids open, etched surfaces, enclosures, crevices. cillators, but this is ridiculous! From this will let the CRT flash to a high Solid state, automatic tuning, portable, the symptoms, your 3.58 -MHz os- brightness. engineered for continuous duty. cillator is not working. This will generally make the picture have a bluish Calibration Voltage In Eico cast, although there is really no 460 Scope "color" present. I'd like to install a voltage regu- NEW Check the 6GH8 color oscillator lator that will keep the calibration tube and all dc voltages around that voltage constant in my Eico 460 stage. Don't overlook the filament scope. It varies when the ac line volt- ULTRASONIC connections either. In some cases, age varies. Do you have a circuit that poor grounding of the heater circuit will do this ? -D. W., Fontana, Calif. 1 has left this tube with a very low fila- Actually, if your ac line voltage 1.] ment voltage, which would make the varies enough to upset the calibration DEEP i; oscillator slow- starting. As a last re- voltage, it will vary the gain of your sort, try a new crystal. vertical amplifier stages in the same ratio, so you don't really have too Intermittent Flashing, Motorola much to worry about! They will both HANDY TS -915 rise or fall by the SONIC same percentage. Tank sire: 5 "x5 ",i3" deep. At odd intervals, the screen of If you do have severe ac line i [sails. 115 volts AC. this Motorola TS -915 flashes brightly, voltage variations in your area, the Heavy Duty Steel Housing. Guaranteed and I lose the picture. 90 days. Heavy retrace first thing to do is chew out the power 569.95 delivered U.S. lines at the same time. Can't pin it company. If this fails, a better way to Order ,,.,.r Mend, Son K, down. -R. G., New Iberia, La. deal with the problem would be to use or more information, from Check the control -grid con- a primary voltage regulator, plugging ÿ BRANSON INSTRUMENTS COMPANY PARROTT DRIVE, SHELTON, nections on the picture tube. In this the whole thing CONN. 06484 into it. There are sev- Send Handy Sonic Ultrasonic Cleaners et S69.95. 1 enclose chassis, they are all tied together and eral of these available. R -E check ['money order D. Send_Handy Sonic information to fed voltage through a voltage divider NAM(

I . network to B+. (Color and video sig- DID YOU MISS ADDRESS I 30 useful projects built around nals are all fed to the CRT cathodes CITY STATE ZIP I RCA the I in this circuit.) CA3018 IC start this month I on page 22. Don't miss them. These resistors are mounted a on L i Circle 76 on reader service card

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4 TV ALIGNMENT - TOOLS S1 110' FLYBACK TRANSFORMER WESTINGHOUSE t intent FM TUNER MARKET SCOOP #t # I n.v.uuauV COLUMN we .e.,o1,01 th Market : l .. n 2tiTS $2.99 4 - TV ALIGNMENT TOOLS 51.49 Latent , l t n 12 UNIVERSAL SPEAKER. I S4 type dart , L J ,I For I t' #2 for all tln.- TVa TV V- 0151101 . . . Tran.l.. 6 - TV COLOR ALIGNMENT S2.79 ItCA, design of large #4 S 3.99 10" PHILCO SPEAKER 5269 Coil postures 18KV -1, tut ' I..Pla I TOOLS '.1_ ur Top quality . maw " assuring adegllale width 5 PNP TRANSISTOR UNIVERSAL SPEAKER $2.49 - S1 Inri Schematic Diagram 300 - ASSORTED HEX NUTS S1 - 1 . 1 . . . . . em.:.I t . arpnrauon r..r TV LargeLar Magnet- ..W pee.al Huy 5 - NPN TRANSISTORS . List pelee UTAH 8" -HEAVY DUTY 10 OZ. Sl 250 - ASST. SOLDERING LUGS SPEAKER corn mle Tvpe -- $3.69 100' TV TWIN LEAD -IN WIRE S2 Your price '3 51 8 Ohm. IV1nse he :o'y duly, clear ,err I , v.. n. f Et 250 -- ASST WOOD 6 "- ECONOMY SPEAKER Top $2.94 UNIVERSAL TV SCREWS $1 quality 2.15 Slag. ANTENNA , o r C 51.98 S" UNIVERSAL TWEETER $1.29 110 TV DEFLECTION YOKE . 250 - ASST. SELF TAPPING 1--J 1 Oz. Magnet $1 SO - ASSORTED TRANSISTORS all SCREWS #,i #8. ele. et 3I UNIVERSAL S1/2" PM SPEAKER $1 Alnico 5 magnet. quality tune 0 TO 200 MICRO AMP MINIA- "COMBINATION SPECIAL" 150 - ASST. 6/32 SCREWS $1 UNIVERSAL 4" PM SPEAKER RCA 110 FLYBACK and 150 6/32 HEX NUTS TURE METER . l'e 'Vt. 51I With 80t,: II.'I, r Transformer $1 plus 110 DEFLECTION YOKE 150 - ASST. 8/32 SCREWS 21/4" x 4" SPEAKER STANDARD. and Si Special 69r 10 - STANDARD TRANSISTORS S1 90 FLYBACK TRANSFORMER 150 -8/32 HEX NUTS NI'N ..,1, 2N31.1, etc. for :.n tspc t', S2 150 ASST. 2/56 SCREWS 31/2" - ROUND SPEAKER 10- ASSORTED DIODE CRYSTALS - S1 $1' and 150 -2/56 HEX NUTS 59` 1N31, IN. In, \d. IN(1.1. etc. . 90° TV DEFLECTION YOKE S2 for all type 'rVs ii. .n.matir .. - 3900OHM -7w RESISTOR S1 3 - TOP BRAND SILICON REC- S1I 150 - ASST. 4/40 SCREWS S1 5e TIFIERS I snip. 1000 I'IS and 150 -4/40 HEX NUTS 20 .47.600v 70° FLYBACK TRANSORMER S - CONDENSERS S1 20 - ASST. PILOT LIGHTS 51 for all type FVo in,l schematic .. W I, ite l'erantic C.I i.- Ameriratt # -t4. 40. .17. 51. elc. 150 - ASST. 5/40 SCREWS S1 3CH6, 7ÚT1ì, 49, and 150 -5/40 HEX NUTS SPECIAL TUBE BUY 50 - ASSampORereTED 1i13AG FUSES S1 70° TV DEFLECTION YOKE S2 4CS0. R 507, 1211117. r:ach p.q,ular rnlh lga vor nil type 'r V', roil schematic .. S00 - ASSORTED RIVETS must 10 ASST. RADIO ti T TUBES S 4 HANKS -UP u.col ..elected sizes $1 - -50' HOOK WIRE $1 2 _ Ty CIRCUIT .BREAKERSBREAKERS Every Tube o glssl number 1 assorted colors 51.19 RAI N 4.2 etc. 500 - ASSORTED WASHERS S1 UTAH 8 " -3 WAY CO-AX 100' -SPOOL SPEAKER WIRE $1.50 m,,.l useful .eltrit,t sizes SPEAKER 30 watt. s Ohm $29.95 2 cond. min i sip. clear. 1 " 1 use. 70° COLOR YOKE 510.95 Special 2 For s7 For all round color C'ItT'e 100 ASST. RUBBER BUMPERS 5 - I.F. COIL TRANSFORMERS 5 - 51 456 -kc for Transistor Radon. for cabinet tot loins a:.dhtt .I , UTAH 12"-3 WAY CO -AX 1 90° COLOR YOKE For all 45 Natta. 8 Ohm SPEAKER 540.95 5 AUDIO OUTPUT TRANS Rectangular 19 to 25" Color S S special 2 For - $i 95 100- ASSORTED RUBBER GROM- .J FORM Sul -min for Trans Radios Am CRT's to METS best tine, Circle 77 on reader service card J UPDATE DIGITAL CLOCK only enough to keep it lighted. !continued front page .55) Sockets are recommended but not There's no substitute necessary. They pay for themselves in decade counter is a transistor- transistor- case of trouble. If sockets are not used for SUCCESS... logic and will operate to 15 MHz. Resis- for the 5750 tubes the wires are long tor- transistor -logic decade counters were enough to reach the terminals. Alpha tried, but we found only a few of them teflon sleeving #TFT 200 for size 22 would operate at 10 MHz. wire should be slipped over the wires. The SN7490 decade counter has been The circuit boards are drilled with a #60 designed so it is possible to effectively drill for mounting the IC and transistor jump the first flip -flop and use the re- sockets and readouts. A size #50 drill is maining flip -flop to count up to six and used for the crystal oscillator. Pliers or reset to O. This makes it possible for the heat absorbers should be used when sol- second "seconds" readout (V5) to dis- dering in the 1N191. Also, do not mount play 1 to 5 (for 10 to 59 seconds) and the resistors too close to the chassis as the second "minutes" readout (V4) to they could cover up the printing. display 1 to 5 (for 10 to 59 minutes) All jumpers and parts are mounted on and reset to zero when it tries to go to a the underside of the board. Also. re- six. The remaining SN7490's are oper- member that the copper on the printed ated as decade counters. All of this is board can he pulled off easily. Solid in- explained in the September. 1969. issue tercom cable makes good hook -up wire; of RADIO -ELECTRONICS. In the fre- and old telephone cable with size 24 JAMES WONG- -Research Engineer quency- dividing chain the input to the wire is ideal. has Heald Eng nee.ing Co e e Graduate It many colors and is first decade counter is 10,000.000 Hz easy to use. As it is necessary to use and the output is 1.000.000. The second some jumpers. letters are shown for this. or IN -CLASS INSTRUCTION! output is 100.000. the third 10.000. 1.- An A goes to an A, B to B. etc. All 000. 100. 10 and finally 1 pulse each grounds go to G and all 5+ points In electronics, it's the training that go to second. These frequencies are so accu- the 5 -volt line. Numbers were used makes the difference. for Employers rate that they can be used for testing. the readouts: IC2 goes to V2. IC3 to require well -trained men and the markers. or "poor man's" secondary V3. etc. Since V2 is wired so it will reset first thing checked is where you standards. to 1 instead of 0. it does not follow the gained your knowledge. Since the clock will never be un- same pattern as the others. Of course, plugged HEALD GRADUATES have many job it is important that all safety VI is used with the 2N3440 transistors. offers with starting salaries often in ex- regulations are observed. An ac fuse Transformers were used for all volt- cess of S10,000 per year. AND advance- type plug (ELMENCO with 1 -amp 3AG ages so the unit would not be of the ac- ment is rapid. fuses) should be used. and if possible the dc variety. unit should be mounted in a well- venti- The complete unit takes 500 mA at 5 GET STARTED NOW. Be a lated metal box. One suggestion is that volts for the decade counter clock unit, DRAT -- TSMAN -12 months the power supply be built in the line 9.5 volts at 3 mA for the crystal os- TECHNICIAN --15 months cord so the clock unit itself can be made cillator and 20 mA at 170 volts. ENGINEER (B.S. A trans- Deg.) -36 months smaller and more variable in design. A former that ARCHITECT (B.S. Deg.) -42 months had these voltages could not size 51/4 X 3 X 21/2" box is about the be found. so a Stancor PS -8416 was YOU are eligible for HEALD ENGI- correct size. If the power supply is on used. It has two windings, 250 volts Cr NEERING COLLEGE if you have a high the same chassis as the clock board. it is and 6.3 volts 1 school education or the equivalent. at amp. For the 9.5 volts possible to use a 7 X 10" printed circuit the transformer can be easily dis- Increased income starts with success- - board and expose the clock section on assembled and 60 turns of No. 32 enam- success starts with your move to Heald. one side or on the front. This will leave eled wire added over the other windings. Send now for FREE brochures with enough unetched copper for the power The transformer can be taken apart more information on Heald in San Fran- supply. quite easily and cisco and your future in Engineering. reassembled without too The printed circuit board is made so much effort. that no other instructions are necessary It took 30 FREE LIFETIME PLACEMENT SERVICE minutes to complete one on do complete this part of the clock. A a trial basis. The windings are held tight VETERAN APPROVED 01'4d cut -out decal is shown that can be put by a small wooden wedge that must be on top of the board with rubber cement. removed before the laminations can be 0 it 0 WRITE TODAY FOR DETAILS This gives the location of the IC transis- taken apart. They should be taken apart -...0 ifr tors, etc., and also the arrows point to one at a time without bending any. The 41.LC$ the direction of the marker on the IC. voltage for the oscillator is not critical. The #1 pin goes toward the direction of Any voltage from 3 to 9.5 worked well. HEALD Engineering College the arrow. Oftentimes, an IC can be in- It is important that the voltage remain 1215 Van Ness Ave. San Francisco. California 94109 stalled in a socket incorrectly without constant so the frequency does not vary. damage. If it is taken out quickly no A Zener is used for the purpose. Anyone Please send me information about: damage will result. but the slightest leak- who does not want to add the turns can ARCHITECTURE age or discharge from the 170-volt line use another transformer of the smallest ENGINEERING: Civil Electrical will completely destroy the IC at once. type available, (12 volts). and a 1200 -ohm Electronic Mechanical So be especially careful with the 170- resistor before the Zener instead of the TECHNOLOGY: Electronic Engineering volt line. 300 -ohm. The 5 -volt power supply Technician (FCC) sup- Generally, a 10 15.000 -ohm, plies Radio.Television Technician (FCC) to t2- the 10 -MHz countdown unit as well DRAFTING: Mechanical Electrical watt dropping resistor is placed in each as the clock unit. They have been sepa- Structural 170 -V lead to the readout tube. A 27.000 - rated so it would be possible to make a I am interested in Day Evening courses ohm resistor should be used to lengthen printed circuit board of the counter or Also send an application.Q the life of the tube. We found that the clock section separately. The clock unit tube has enough brightness and would can he used as a slave so that it does not strike each time. The purpose of this re- need the countdown section. R -E AYE 116E sistor is that when no current flows there ACstest is no voltage drop. and the full 170 volts

CITY is on the tube. When the switch is closed COMING IN OCTOBER in the readout driver, IC current flows Don't miss R -E's special hi -fi issue. STATE and the current drops to a safe oper- Learn all about the latest stereo and the tube has \IP PHONE ating value. After fired it 4- channel equipment. r no longer needs this high voltage, but Circle 78 on reader service card 68 RADIOELECTRONICS ANOTHER COMPUTER TRY THIS ONE BOARD SPECIAL BOOST YOUR EYE POWER DON'T LOSE THOSE If you are one of the thousands SOLDERING TIPS who wear glasses and work in the field Various size soldering tips won't of electronics, you probably have been get lost if you clip them into a multi - faced with the problem of trying to fuse block attached to your bench sol- read some schematics and when re- dering iron control box. A two -inch pairing or replacing some of today's Honeywell Power Board contains 4 2N1137B miniaturized components. At such 80 watt PNP power transistors, 8 Top Hat diodes, 8 precision resistors and 41N642 diodes times you have probably wished for stock No. B9093 1.25 ea. another pair of hands to hold a magnifying glass. Well, you don't have to Stock No. B9082. feeling Honeywell Computer boards. 41'2" x 12 ". Tran- have that frustrated anymore. sistors, diodes, zeners, capacitors, precision resistors, heat sinks, trimmers etc. 3 Different 6X5 MM MAGNIFYING CHIP boards $1.00.

Integrated Circuits Stk. No. Type Case Function Price B3000 907 T0.5 Four input gate 75

63001 914 T0.5 Dual 2 input gate .. . .90 B3008 914 FP Dual 2 input gate 90 Just go to your optometrist and have B3002 915 TO-5 Dual 3 input gate .. .90 B3003 923 TO-5 11( Flip Flop 1.00

him cement a magnifying chip (7 to 83007 3M4 -923 FP JK Flip Flop .... . 1.00 12 in B3005 1M4 -925 FP Dual 2 input gate exp. .75 power) the corner of your 83004 926 T0.5 Buffered JK Flip Flop ...1.00 lens -left or right depending upon 03006 926 FP Buffered JR Flip Flop ... 1.00 B3009 927 TO-5 quad inverter 85 personal choice. The chip will end up 83010 903 T0 -5 3 input gate 75 15 6 when ce- B3011 902 T0.5 RS Flip Flop 90 about mm x mm, and B3012 904 TO-5 Half adder 90 mented to the back side of your lens, 63013 900 T0.5 Buffer 75 you will find that it will not interfere Lots of other items-send for free flier; all mer- with normal vision. When you have to pipe cap, filled with steel wool, at- chandise fully guaranteed. Please include postage; excess will be refunded. take a close look at a printed circuit tached to either your bench or solder- board, you have both hands free to ing iron case allows a one handed hold components and inspect for dam- "dunking" operation to clean the sol- DELTA ELECTRONICS CO. age, etc. The cost will generally be dering iron tip. John F. Agee. BOX 1, LYNN, MASSACHUSETTS 01903 less than $10.- Edward F. Xiques K5ODN R -E ( ircle 79 on reader service card no other heat gun... otters all these attachments

Attachments to speed your job ... For shri4ing attachments that tailor Master heat gun airflow precisely to your needs thermoplastic ... attachments that fit any existing tubing and Film, Master flameless heat gun. No other Forming, line offers so many choices ... curing, including the exclusive patented melting, drying, cone for 1/4 " concentrated heat, optional adjustable base, convenient carrying soldering. case, and the only U.L. listed gun available. Send for free 12 page catalog.

MASTER Racine, WI 53403 Circle 80 on reader service card AUGUST 1970 69 Save Time NOTEWORTHY on PC Board Repairs! CIRCUITS LOW -LEVEL CURRENT -REGULATED the interims, it is kept busy as a re- POWER SUPPLY juvenator and trickle charger for MODEL IUOA flashlight batteries! The current-regulated power sup- When the instrument is initially ply shown in the photo and schematic put into service, a voltmeter is con- r is simple to build and occupies little nected temporarily across capacitor space on the test bench. Nevertheless, CI, and potentiometer RI is adjusted

Melted solder disappears up hollow tip 25mA into tube CURRENT LEVEL RI R2 R3 The ENDECO Desoldering Iron 50051 22011 I5Wn T 5W IW Removes Soldered Components 01 in seconds...without damage! 40321 NEG Endeco melts solder; removes last trace OUTPUT by vacuum. Leaves SI terminals and POS. mounting holes clean. Resolders PC S2 PUSH boards better than regular iron. One - T SET hand operation. Temperature controlled 117 VAC OUTPUT for continuous use. Standard tip furn- INPUT CURRENT ished, 5 other tip sizes. Pays for itself. $20.65 net. Smaller size available. See FI your distributor or write: Note: R2 is 4K, 5W 1 /2A NO 47 ENTERPRISE PILOT DEVELOPMENT it comes in eery handy indeed for for a meter reading of 125 to 130 CORPORATION those frequent little jobs such as test- volts. The output current will then be 5127 E. 65th Indianapolis, Ind. 46220 ing neon lamps and Zener diodes. In continuously variable from I mA Circle 81 on reader service card (with the resistance of R2 entirely in

Protect and Preserve Your Copies of Radio -Electronics An elegant, durable Li- brary Case will protect an entire year's copies from . %p dust and wear. \ecOC At the some Modules, s, time, it will Y\ Speakers. \J \ Stereo, Hi -Fi. enable you to v Photo Cells and valuable space thousands of conserve and reduce book- a other case clutter. Electronic Parts. Send for With Maroon simulated leather back, and FREE black sides, the attractive case should be e catalog a handsome addition to your library. (16 -k r: . rrs gold lettering is used to give maximum legibility.) Each Library Case also includes the circuit) to 25 mA (when the re- gold transfer so you can print the year on sistance of R2 is zero). In any init. To order, send your check with the order dividual instrument, it may he neces- form, below: sary to alter the value of R3 slightly, 1 one way or the other, to obtain Clip 8 Mail with your check to: ex- JESSE JONES BOX CORP. actly 25 mA output when R3 is set in 111 1111 1111 M M II NI M MI1 1111 Box 5120, Philadelphia, Pa. 19141 its fully clockwise position. -Frank H. ELECTRONIC DISTRIBUTORS INC. Tooker R -E Dept. TA -2, 4900 Elston name Chicago, III. 60630 address RUSH CATALOG COMING NEXT MONTH city Build an anti -sleep alarm for your Name state zip car -it's a life saver. Address Please send me RADIO -ELECTRONICS Find out how to make a printed cir- Library Cases at $3 50 per Case. (Payment cuit without messy etching. City State Zip Code must accompany order.) Interference in TV reception can be stopped if you follow Jack Darr's tips. es Orders outside U.S.A. not accepted IlmCircle 82 on readerm service card 70 RADIO -ELECTRONICS PORTABLE VTR'S (continued from page 62)

drives a voltage regulator that controls the vidicon's target voltage. In this way a constant video level is assured over a wide range of lighting conditions. COMING Output video is also routed to a signal processor where the signal is clamped and applied to an output emitter follower. Vertical and horizontal sync are added to the NEXT signal at the input to the emitter follower. One output of the emitter follower drives a voltage amplifier through the contrast control to supply about 40 volts p-p for the viewfinder CRT. The remaining output lead of the emitter fol- MONTH lower is routed through the connecting cable to the vtr. The camera uses two deflection oscillators (vertical and horizontal) that are driven by V &H drive sent up from the vtr. Each deflection oscillator drives a pair of SEPTEMBER 1970 deflection- output systems. One deflection system drives the yoke on the vidicon; the other drives the yoke on the f- inch CRT. Retrace pulses produced in the oscillators and flyback transformers are used as byproducts to generate H and V sync. A pulse- stretching blanking amplifier also uses these pulses to generate blanking signals. TV Antennas is the special topic The photo shows the guts of the DVC -2400. Note this month. We've got three hot that the viewfinder CRT uses a small doughnut- shaped PM magnet to adjust focus. antenna articles for you. Most vtr manufacturers are now taking the wraps off a new family of 1/2-inch vtr's built to the EIAJ standards (EIAJ = EIA of Japan). Included in these families are All About UHF Antennas brand -new portables. The photos show some of the newest. The Sony AV -3400 has a sophisticated two -motor servo Tells about the different kinds system that permits the servo to lock up to externally supplied video as well as the video supplied by the captive of antenna designs. Details ad- camera. It also can rewind and play back the tape with the vantages and disadvantages. picture appearing in the viewfinder. An optional modulator permits the operator to see the video on any TV set. R -1 Antenna Secrets rJ COAX All antenna needs are not alike. Each installation has its own problems. See how to set up WALL TAPS your antenna to deliver maximum performance. For UHF VHF Color B &W TV Antenna Installers Manual A complete guide to antenna installation techniques presented in R-Es Reference Manual Designed for ease of Format. installation ... Mosley provides the new MC Series of solderless Wall Taps to ALSO: meet all your 75 ohm coax lead -in requirements - from Kwik -Fix Troubleshooting Charts the single lead -in outlet to Jack Darrs Service Clinic the more complex multi- Anti -Sleep Alarm To Build unit distribution For Your Car system. Build Computerized Electronic Music Synthesizer Write Dept. for FREE detailed brochure. `158A N. Lindbergh Blvd., M Dkfcf on Br dgeon Missouri 63042 Circle 83 on reader service care! A U G U S T 1 4 7 0 71 ADVERTISING MARKET INDEX RADIO- ELECTRONICS does not assume responsibility for any errors which may CENTER appear in the index below.

JAPANESE NEW PRODUCTS MONTHLY! $1.00. READER SERVICE CARD NO. PAGE Refundable. DEERE, 10639 Riverside, North ELECTRONICS Hollywood, Calif. 9 Artisan Organs 20

67 Blulyne Electronic Corp. 60 RADIO AND TV TUBES 330 each. One year RECEIVING & INDUSTRIAL TUBES, TRANSIS- TORS, All Brands Discounts. Techni- 76 Branson Instruments Co. 67 guaranteed. Plus many unusual electronic bar- -Biggest 77 Brooks gains. cians, Hobbyists, Experimenters- Request FREE Radio & TV Corp. 66-7 Free catalog. CORNELL 4217 -E Univer- 70 Burstein -Applebee Company 62 sity, San Diego, Cal. 92105. Giant Catalog and SAVE! 2ALYTRON, 469 Jeri- cho Turnpike, Mineola, N.Y. 11501. TECHNICIANS & ENGINEERS. Teach yourself 13 Channel Master 25 89 Computer Logic and advance professionally. 6- TRANSISTOR ALTERNATOR Voltage Regu- Chemtronics Cover III COMP -U -KIT Logic Lab with modern type 74 lator. Fits most cars. Free literature. YUENGER 15 Cleveland Institute of Electronics ..... 42 -5 microcircuits, a quality patch system, and our ENGINEERING CO., 13381 Wheeler Pl., Santa CREI. Home Study Division of McGraw - outstanding logic handbook is only $39 post- Ana, Calif. 92705. Hill Book Co. 29 paid. Free literature. SCIENTIFIC MEASURE- 63 Crystek, Division of Whitehall MENTS, C125, 9701 Kenton, Skokie. III. 60076. Electronics 58 EXCITING LISTENING! Police- Fire -Emergency BUILD: TRANSFORMERS, INDUCTORS your- calls on your broadcast radio. $19.95 up! Re- self. Save. Free estimates and information. tail- Wholesale. Also crystals- receivers, Scan- 79 Delta Electronics Co. 69 100. 65 Delta Products, MAGNETIC CIRCUITS, 386 Deborah Ct., Dept. ners, dualband High /Low. Brochures Inc. 59 B, Upland, Calif. 91786. SALCH COMPANY, Woodsboro 43, Texas 73 Denson Electronic Corp. 64 78393. CONVERT any television to sensitive Big- Screen 82 Electronic Distributors, Inc. 70 Oscilloscope. Only minor changes required. No Discharge IGNITION, PHOTOFLASH. Free cata- EMC Electronic log parts, kits. TRANSPARK, Carlisle, Mass. Measurement Corp. - 63 electronic experience necessary. Illustrated 81 Enterprise Development Corp. 70 plans $2.00. RELCO -A25, Box 10563, Houston, 01741 Texas 77018 8 Finney Co. 15 COLOR ORGAN KITS $3.25 to $7.50. Power Sensing unit for construction of ELECTRONIC Supplies $2.75. Catalog. MURPHY, 204 Roslyn AC MICROAMMETER. Sine, distorted etc., Ave., with instructions. CHRONAGRAPH SPE- I G- CElectronics Cover II Carle Place, N.Y, 11514. $14.95 2 CIALISTS, P.O. Box 132, Stanton, Calif. 90680. Grantham School of Electronics 1 Ultra- sensitive and powerful METAL DETEC- TORS join the many who are finding buried 78 Heald Engineering Philco model G8002. College 68 coins, minerals, relics and artifacts. Don't buy UHF SIGNAL GENERATOR 4 Heath Co 7 till you see our free catalog of new models. Never used, in factory carton. Original net Write JETCO -Box 132 -RE. Huntsville, Texas $289.50. Sell $45.00 shipping collect. EARL 77340 SHEETS, 352 Mound Street, Logan, Ohio 43138. 88 International Crystal Mfg. Co. 76

74 Johnson Co., E.F. 65

Independent News Company, Inc. is announce a Retail Display Plan which in- pleased to 6 Leader Instrument Co. 14 cludes Radio -Electronics as part of a group of magazines available for the earning of a Display Allowance. 80 Master Appliance Corp. 69 To obtain details and a copy write to Marketing Depart- 3 of the formal contract please Mallory Distributor Products Co. 5 ment, Independent News Co., Inc., 909 Third Avenue, New York 10022 (Attention Mr. 83 Mosley Electronics Inc. Paul Hendershott). Under the Retail Display Plan in consideration of your acceptance and 71 fulfillment of the terms of formal contract to be sent to you upon request, you will receive a Display Allowance of 10% of the cover price per copy of each magazine in the group sold National Radio Institute 16-19 by you. This plan will become effective with all issues of the magazine group delivered to 71 Nelson- Hershfield Electronics 63 you subsequent to the date your written acceptance is received and accepted by our Company. 75 Olson Electronics. Inc. 66 11 Precision Electronics 20

72 Quam Nichols Co. 64 CLASSIFIED ADVERTISING ORDER FORM RCA Electronic Components 14 Microphones 27 Tubes Cover IV RCA Institutes 23 1 2 3 4 5 64 S & A Electronics 59 l0 SCA Services Corp. 20 68 Schober Organ Co. 61 7 8 9 10 69 Sencore 61 7 Sonar Radio Corp. 14 I2 Sony 21 62 12 13 14 15 Spectrum Products Co. 58 Sylvania 8

12 TEAC Corp. of 16 1 18 19 20 America 13 61 United Technical Institute. Division of Career Academy 57 23 2 25 66 Xcelite, Inc. 60 27 28 29 30 - MARKET CENTER 72-75 Bele Electronics 31 32 33 34 35 84 Edmund Scientific Co. Fair Radio Sales

J @ .30 Non -Commercial Retest Houle Mfg. Co. Lakeside Industries No. of Words l @ .70 Commercial Rate No. of Words in bold caps RAW Monogram Publications, Inc. @ .10 Music Associated ADDRESS 85 Park Electronic Products letal Enclosed $ 86 Polypaks 87 Payment must ac- CITY STATE ZIP Solid State Sales times) company order un- Surplus Center Insert less placed SIGNATURE through accred - SCHOOL DIRECTORY 75 Starting with Issue ited advertising MAIL TO: RADIO -ELECTRONICS, CLASSIFIED AD DEPT., agency 28 200 PARK AVE. SOUTH, NEW YORK. N.Y. 10003 Tri -State College Valparaiso Technical Institute 72 RADIO- ELECTRONICS 30 I.C. Projects N átt 1000's OF UNUSUAL SCIENTIFIC BARGAINS,ei2C'liring binder. tation. salt water. snow or lee. Instant signal on widevlew $3.( Ppd. outer and headset lone when object detected. Rugged. Using closely spaced wire probes, it lightweight (3t, lbs.). trouble -free unit uses inexpensive LONG WAVE BLACK LIGHT FIXTURE q volt battery (included -130 hour life). can be used to sound an alarm or turn Extremely versatile. rom - Stock No. 80.190EH 5163.50 Ppd. when . pae'tly deIgned, lung wave ROTATING MULTI- COLORED off electrical supplies steam im- I black LIGHT : :tun -401011 angstrom: Dazzling colors stream end - pinges on both probes simultaneously :Ma (ultraviolet) Oxlure- le -sly from constantly rota- ultra oleo rat shorter ting light. Facetted. trans- (to automatically turn off an electric r ultraviolet rays. l'sr to parent cicnthfy minerals. fungi. globe has louvered as soon as the water reaches the drum inside with red. green, kettle bacteria check for surface blue & yellnnc stars. Bulb and gas leakage- boiling point). flaws. oil heal rotor- drum which pro- - displays with perfect for tir jects flickering star points ore -rent tutee. paints. Chalk. on walls, ceilings. etc. while .... r I. lu. adjustable aluminum reflector. imlinidual globe fairs pre- mur, I ing plug. Mount vert.. horiz.. sent constant ly hanging ar- 1... It, W., It"," II. ray of brilliant colors. ,tai. Stuck N.. i4EH Ppd. Iii -i $12.50 star-- approx. 12" high on ben -shaped base. Surprisingly No. 00.124EH REPLACEMENT BULB 54.50 Ppd. TO ... Ilght. F :eel ly Placed on table. TV, fireplace, or Xmas tree top. o Stook No. 71.000E II Ppd. PARKING NEW. LOW -COST GEM TUMBLER 36.00 o LIGHT PLUG -IN ULTRASONIC ALARM /LIGHTER a Easel R3 .i' SWITCH Become ruekhoundI Silent. ravnomiral. easy lo .. noting hubby . loads of IOOK - in -tall. No special attach- fun. inexpensive. vast'. Make ments or electrician needed. Jew cloy of all kinds-- derora- .lust plug in -nrket- -then tire look -ends. table lop, plug lights and /or alarm et e. Simply tumble-OM dl Into It. .\rl bole- when it readily available or'lntonca "hears" -nunr'oor. ((,et then polish to high automatically. titre-sensi- 111.1re . brings out beau- tive up 10 310 ft. Sensitivity tiful colors. (tugged 3 -hr. 'a- control call adjust out pet ' Pariy tumbler nv /root inuous noise. Convenient for night ,any r .r. l' w -u r., limts. light- eliminates fumbling Stock No. 70.874EH $10.75 Ppd. or injuy in darkness. Ideal for :aaarttnla1. home. uniri', 6 -Ib. ROCK ASSORTMENT (10 TYPES) Plant. 'Walnut ttti.II with built-lit riwrr, an - IT sat itch. Stock No. 70.868EH S 9.00 Ppd. 'í'.K7.11 frittannco: I10-130v. 610 M.SC. Stock No. 71.283EH (IOxë X 3!

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ARKAY MAND, Dept. 102, Box 238, New Baltimore, Michigan ELECTRONICS, 1028E Commonwealth Avenue, Box 26348 -E, San Francisco 94126. 48047 Boston, Mass. 02215 FCC FIRST CLASS LICENSE in three -four weeks. School in Nashville, Jacksonville, ENJOY THE ULTIMATE in stereophonic sound, Philadelphia. and using stereo headphones, $20.00 per pair. Write AMERICAN INSTITUTE OF -FI RADIO, 2622 Old Lebanon Road, Nashville, AUDIO - HI LASSITER, Box 474, Port Hueneme, Calif. Tenn. 93041. 37214. WRI fE for highest discounts on components, TV TUBE TUNER REPAIRS- Complete Course De- recorders, tapes, from franchised distributors. & STEREO Needle Sale. Up to 90% off tails, 12 Repair Tricks, FREE all brands. Serviceman, Hobbyist, Stereo Own- Many Plans. Two Les- Send for monthly specials. CARSTON, sons, all for $1. Refundable. FRANK RFD #3, Route 7, Brookfield, Conn. 06804 ers, Free List. J. KNIGHT TV, 612 Gaines Ave.. BOCEK, Box 3236 (Enterprise), Redding, Calif. 96001. FM BACKGROUND MUSIC ADAPTER. Compact Hot Springs, Ark. 71901. ELECTRONICS ENGINEERING. line -powered Musicon MX -7 plugs into an FM RENT 4 -TRACK OPEN REEL TAPES major Day or evening -all classes. Bachelor of Science Program Tuner or Receiver. Optimized design guaran- labels -3.000 different. Free brochure. nings. Associate eve- tees 5 years of commercial -free music without in Science Program day or STEREO -PARTI, 55 St. James Drive, Santa night. If you are adjustments! Works with your equipment or Rosa, Cal. 95401 married or if you must work we Send for a living while obtaining your education, refund. stamped self- addressed enve- this is lope for SCA stations in your area. Lowest NEW BSR RECORD CHANGERS: $13.00. the college for you. Approved for Veter- McDonald 300 400 ans. WESTERN STATES COLLEGE price ever -$35 postpaid from K -LAB, Box -$18.00; -$20.00; 500- NEERING, OF ENGI- 572R. S. Norwalk, Conn. 06856. $25.00: AM /FM component system -$50.00 970 West Manchester Avenue, In- DAVIS, Dept. RE, 2737 Third Ave., Bronx, N.Y. glewood, California 90301 10451. IS? OOV:T FREE Catalog Tapemates makes available to you ALL 4- SURPLUS ELECTRONIC BARGAINS TRACK STEREO TAPES. All Labels- postpaid to PEP'$ Dollar Sale your door -at tremendous savings. For free bro- Now B I G G E R a n d chure write: TAPEMATES CLUB, 5280 RE West Money Back guarantee BETTER Pico Blvd., Los Angeles, Calif. 90019. si $i Than Ever! 1 Amp Silicon Rectifier' 7 AMP choice of package SCR - -MAIL THIS COUPON NOW- Bullet- Miniature Glass- n 4 -50V units $1.00 Metal n 2200V units $1.00 GENERAL -so0V units n 5.800v units $1.00 n $1.00 (1 41000V units n 1 -500V unit $1.00 PRINTED $1.00 CIRCUITS custom built to your de- 3.1200V units $1.00 n 1.800V unit $1.50 sign. Ever have a circuit that would be great 20 AMP SCR ADDRESS- on printed board but the cost was prohibitive? 3 AMP Epoxy Package n 2.50V units $1.00 We will build you a 3 by 5 board for $2.00 [1 10-100V units $1.00 n 1-300v unit $1.50 postpaid! You design a negative using our 5 -400V CITY: STATE: ZIP- units $1.00 Gen Purpose PNP easy format system, we'll do the rest. Send n 2.1000V units $1.001 $1.00 for complete details and materials to Germ Transistor Similar For your FREE copy, out coupon and moil. Dept. RE to 20404 fill make circuit negatives. L. L. STEVENS SUP- S AMP Epoxy Package For $1.00 PLY & REPAIR CO., Camden, New York 13316. E1 8 -100V units $1.00 8 FAIR RADIO SALES [ i 6.200V units ZENER DIODES 1016 E. EUREKA Box 1105 LIMA, OHIO 45802 FREE "Directory of 500 Corporations Seeking $1.00 3 -800v units $1.00 3 Watt New Products." For information regarding developments, sale. licensing of your patented /un. 10 Volts SILICON STUD MOUNT n 3 units $1.00 ENJOY THE "MUSIC ONLY" FM PROGRAMS patented invention. Write: RAYMOND LEE OR- 12 AMP ZENER DIODES 1 Watt GANIZATION, 230 -U Park Avenue, New York City ri 5 -100V units $1.00 10017. 2ß00V units $1.00 1 EA 4V-6V-8V-10V 4 units $1.00 10 1 -1000V units $1.00 D M. A. D. GERM GLASS DIODES MUSIC ASSOCIATED'S DETECTOR INVENTIONS SILICON STUD MOUNT DO7 GEN PURPOSE for continuous, commercial -free 20 AMP 20 Units $1.00 music & PATENTS 3 -100V units Replaces 1N -34 with ANY FM tuner or receiver n $1.00 1N -60 I-1 1.1000V unit $1.50 IN-64 1N295 INVENTIONS WANTED. Patented: Unpatented. I.C. SUMMER SPECIAL GLOBAL MARKETING, 2420 -AE 77th Ave., Oak- 14 Lead Dual In -Line Pkg. land, Calif. 94605 Perform some function as 7000 series INVENTORS: protect yr,ur ideas! Free "rec- Master Slave Flip Flop 750 @ -5 -$3.00 ommended procedure ". WASHINGTON IN- Quad 2 Input Nand Gate 750 @ -5 -$3.00 VENTORS SERVICE, 422X Washington Build- 16 Bit Memory Ce11-$4.25 ing., Washington. D.C. 20005 14 Lead Dual In -Line Pkg. r CIRCUIT BOARD COLOSSAL 3 different groupings to choose from Typical samples below GOVERNMENT A) 4 I.C. mounting blocks-3 transistors-over 25 resistors complete with board! Price $1.25 SURPLUS B) 32 transistors -over 100 resistors- capacitors- S.C.R.'s over 15 diodes -complete with board! Price $1.75 Kit $49.50 Wired $75.00 Cover $4.95 List of FM JEEPS Typically from $53.90 . . Trucks From C) 22 -14 lead dual in -line I.C.'s -over 75 diodes stations with SCA authorization $1.00. For com- transistors - plete Information write nr call- $78.40. . Boats, Typewriters, Airplanes, capacitors-20 -over 50 resistors -complete with board! Price MUSIC ASSOCIATED Multimeters, Oscilloscopes, Transceivers, Elec- $4.50 tronics Equipment. Used. 100,000 Bid Bargains FULL WAVE BRIDGES 65 Glenwood Rd., Direct From Government Nationwide. Complete PRV 2Amp I 3Amp 1 5Amp 110Amp Upper Montclair, N.J. 07043 Sales Directory and Surplus Catalog $1.00 (De- phone 201- 744 -3387 ductible First $10.00 Order). SURPLUS SERVICE, 50V 1.25 I 1.35 I 1.50 1_ 1.70

Box 820 REL. Holland. Michigan 49423 100V 1.50 1 1.60 1 1.75 1-1.95

200v 1.75 I 1.85 I 2.00 1 2.20 BACK ISSUES WANTED 400v 2.00 I 2.10 I 2.25 I 2.45_ I 2.50 1 2.60 2.75 1 Television, Television News, Short Ware 600V 2.95 of the following magazines: Craft, ' 800V 3.00 I 3.10 3.25 I 3.45 Short Wave and Television, Radio and Television, Radio News. Also other PARK ELECTRONIC magazines on the same subjects. Pre 1950 only. Quote exact dates, titles PRODUCTS and prices in first letter. P. O. Box 78 N. Salem, N. H. 03073 Tel. (603) 893 -0276 Monogram Publications, Inc., 21839 So. Avalon Blvd., Torrance, Ca. 9(1502 NO SALES TAX WE PAY POSTAGE Circle 85 on reader service card 74 RADIO -ELECTRONICS BRAND NEW! GENERAL ELECTRIC 709C OP PA -237 2 -WATT Pj1c.s SCHOOL AMPLIFIER AUDIO AMPLIFIER woe'. Guaranteed! With Spec. TvmCat IBM 2 watts continuous 9 fo 27 volt supply. 8 mV sen. -ac SWUM! 49 'e,sa s tivty, includes II c;rcuifs, for phono, tape re- PHONO PetM1 $3.95 1.111GaalOe 1 DIRECTORY corders. dictatinq, TV, FM, rho,.. 'MVllimde BRAND NEW! RTL -TTL 'ICS' SOLID STATE 1970 WINNERS_ Fairchild A1.1. (l': \ RANT l';1';I With Spec Sheets: 741 OP. Amplifier' $2.98 distinguished graduates frequency compensated 709 ., .... I. LI wit,. C ., sol m nnirenna,t t) I(tJ il- Westinghouse Voltage Regulator rut U.S. Prof .ü.n;,I N' t,d [college uIth , mtmtanding 994 ..',e, 0 to 40 VDC Positive =1.19 Placement rectos'. F.,ur- yuartcr year permits . legree In Shockley three years. Dedicated faculty. Modern Tabs. Small classes. Each Diodes, 4 layers 3 for $1.19 4011 -erre ^ mpus. Accredited. AIprrod. for r7 Neon & Nixie Driver 2N4410 4 for $1.00 Sept 3 for $2.75 IA vets. Moderate total costs. Enter . SCR'Triac Trigger Diodes 4 for 51.19 March, June. For ('0101 ff. a' rite Admis.ion.. Description SG43SD Dual 4 Input Ns-id /Nor Gate... TTL TFjrqS/ TRI -STATE COLLEGE W215F JK Flip Flop DTL 1.ln0 I li el;r Avenue. Angola. :ndi:ina 407113 0 W266F Quad 2 Input Gate DTL IA 320T JK Flip Flop (fastest logic) ECL TONA(¡ GET INTO ç.)900FF Buffer RTL Ú/T D L l 908TÚ Full Adder RTL G E909TÚ °^ e Buffer RTL /D: / S ELECTRONICS 912TÚ Half Adder RTL /pec S.1.1. uunlag usas 10 uer L 913TU Shift Register RTL Shee/j technicians. veld engineers. specialists j914TF Dual 2 RTL pu`eate In communication.. guided mlllea. Input Gate. ad ou computers. radar and utometlon. Bale L1923TF JK Flip Flop RTL S advanced cour.. In theory labor. O 960TU Dual Buffer 1°A h r .... tg7 07470FX RTL SN90 0 & Electronic Technologygg rurhnul.rriru la JK Flip Flop (35mhz) TTL C prjer...... ,i4ys both available. A..elate degree In 29 LÌ7302FX Dual SN77SOu`aded 14.1 JK Flip Flop DTL 9J0/ C °ynlr 3.95 moo. B.S. also obtainble. 0.1. ap- 0184 ROUF Quad 2 Input Gates [l -..... proved. Graduates In all branches of TTL 930d 1la-1 Dec `h .. 4 95 electronic. with major companies. Start '.. Sept.. Feb. Dorm.. campus. High o BeD p0 !r ... SD school graduate or equivalent. Catalog. EPDXY SILICON TRANSISTORS ' 9 Type Sale O 0Ó ...... `: ! 9 VALPARAISO TECHNICAL 2N2222 5 for $1 u U'/P' 4 5p INSTITUTE p 2N2368 5for$1 Fill/,fdae¡f Resfrfe y 96 Dept. C. Valparaiso, 46383 Indiana 2N3396 5 for $1 5 for $1` 2N3565 rZ49 5 for $1 4 ys 2N3568 5 for $1 2N3793 5 for $1 R2N3638 I 2N4248 5 for $1 5 for $1 Í 0 Fairchild 1128 8 bit $2.49 2N3641 -3 2N4288 -9 5 for 'MEMORIES" TO ALL 5 for $1 $1 Fairchild 9033 16 bit $3.98 WHOLESALE 2N3645 5 for $1 Philco PL5R100 for 1970? Dual 50 bit $12.50 Breadboard Kits -"RF" Kits-"PC" Kits -Pert. 9 4000 Bit Core Planes $8.50 Phenolic Board-Copper Clad Board-Cowl Type Terms: 01111 pnstnge. Rated: net 30. cod's 25% Electronic Cabinets -Heat Sinks -Solid State Hobby Phone Orders: \\akefield. Mass. (617) 245 -3829 Westinghouse WC334 one watt audio '49 Kits -Solderless Connectors -Hardware Kits-Tran- Retail: 211 Albion. St., Wakefield, Mass. amp. TO -5 case Guaranteed! sistor Sockets and many more items. Send for free P.O. catalog from: H. M. C. Sales -P. 0. Box 276 - BOX 942R. LYNNFIELD. MASS FOR OUR "SUMMER" BARGAIN CATALOG ON: Santa Susana, California 93063 POLY PAKS 1 01940 O n Semiconductors Poly Pak, Parts Circle 86 on reader service card U.S. GOV'T ELECTRONIC SURPLUS Rebuild Your Own Picture Tubes? With I.akeJde Itldnstries pre - Nationally Known World Famous SURPLUS CENTER Oita HOBBYISTS, EXPERIMENTERS; BLACK AND cl.slon equipment. you can rebuild any tube! finest. mast espensive, Government Surplus electronic units and WHITE TELEVISION CONVERTED TO COLOR picture components at a traction if Meir engine' acquisition test. Forcomplete details. mail coupon. BY MEANS OF A NEW PATENTED COLOR Lakeside Industries BURGLAR -FIRE ALARM SYSTEM CONVERTER ADAPTOR. INSTALLATION ALL 5234 N. Clark St. t ITEM li 135 -A) -- Dual alarm FOR FREE BRO- Chicago. Ill. 60640 .stem ene9 naming of lire or trrak.m. DO IT YOURSELF. WRITE Phone: 312- 271 -3399 operates Oa 113 -SAC. Conlml 2- . unit, BELE ELECTRONICS CORP., 111 N.E. NAME hid& flash fire, 3- CHURE. mercury column. Jdonr ADDRESS '1 inMlw scmaturs. alarm hen. Inn Il. SECOND AVE., MIAMI, FLORIDA 33132. "xS29.95 ,urnmMrm'b.ms.e'2 "a 7,1 53 ".171..1 CITY STATE ZIP POCKET SIZE MULTI -RANGE TESTER (ITEM nAl011 -- ,,I l.,., ry(Olrot 011 to and' ' Het Ironic equipment. \. .lellt10rl' ,...r., RECTIFIERS lfana.nnrmd equipment. pas pist coon rest - CIRCUITS f lor 250.m, mama II. 4r,. , m .t ...ean scale Irllh superior teadab,hl. TRIACS law ranges. SEMICONDUCTORS f s -.., AC Volts; 0.10.10.234000. DC s.' ' 0-5.21.121.300.2300. current. 0-230 mil.. mm ohms: 0.10 OOP 11 and I Meg íe011 ER900 TRIGGER DIODES. These SE 161 ONE SHOTS $1.95 FIBRE OPTICS ohm - low scale,. Du: -21 to phis 22. Oman biodirectlanal trigger diodes are one US 908 FULL ADDERS .85 I 2.5 mil. fibers in PVC packet. r /32. 9g n T ¡ n 1 "i anélrm woo leather of the best and cheapest methods to US 913 REGISTERS .85 f .33/It. $8.98 . 1 Ir.l., in.n11. i.m.. : u..., "''. trigger SCR's and triers .3/91.00 US 940 JK FLIP FLOP .85 COMPLETE LIGHT GUIDE UNIJUNCTIONS! TTL IC SERIES EXPANDED SCALE 0 - 15 DCVM to 2N2419. RBB of 5.7 stand BUNDLE Similar $3.95 of 32" off ratio of .6 and Ip of 12 with data DECADE DIVIDER consisting of an II" length I! RF 112 1.50 ends. ( 21401) - - hand ors, espen.nr ,nllmelet sheet $1.00 Dual JK Flip Flop dia. fiber optics with bound P.M. 9,110 th-tolls IN' and 3 tu m- roll.. 1 n 11.4.1111 FET'S TO -18 MC 415 JK Flip Flop ...... 85 $2.00 ea. for ,m..t4. and aircraft batten .narre ',mlutot. Cal NCHANNEL units. tons not -e. tun' MC 400 Dual 4 input 709C OPERATIONAL AMPL. ole tram. al m... t. mark In,,rmle u... plastic' .85 ea. leakage. 27. volts ..Urge to gate. 30 NAND /NOR gate $1.45 4 Resister 1.75 11.1.1.10 $12.95 ma gate current train to WIIIII uu,ho's. Bit Storage Controlled Avalanche or s .80 9301 MSI ONE -OF -TEN Epoxy Rectifiers 1 AMP. LIGHT OR NIXIE DECODER 2.95 METER nNEON DRIVERS. An NPN. PRY PRY RUNNING TIME TUBE Power Rectifiers TO.Il. SI Trap -i -tor. With a \'l'ISO Silicon 100 I .07 600 .16 t nix-IM I..I Se to record number of op- of 120 3/81.00 of electric SII PRY 3A I_ 12A I 30A 200 1 800 .20 deiorrstx as furnaces. MOUNTING .09 m'I.ado luau hour, tenths .ne hundredths ip HARDWARE KITS. 100 .09 .24 _I .50 to 9.999.99 hour.. For 115.1011. 00- .acte.. 400 I .11 I 1000 .30 Stunning These kits are used to mount our sire 4'... I 1.x2', . weight 21 .. 65.69 200 .16 _.35 I .80 4. .,., o,., ,!.1.00 SCR' o 'Genet. and Rectifiers rte. Silicon Control Rectifiers 6n32 stud (3. 12 amp rectifiers. 400 .20 .45 I 1.20 , , , 70A 7A SCR's) 6 sets /$1.00 PRY 3A 7A 20A COMPUTER ON HEAT SINKS 600 .30 .70 I 1.50 TRANSISTORS 1Vaa28 stud (30 amp. rectifiers. 501 .351 .451 .70, amps 4 sets /$1.00 rsM Computer Quality Units 20 SCR's) 800 .40 .85 I 1.80

I_ 1 1.00 4.00 TRIACS_ 100 1 .50 .65 I 2.20 (njj . no, wmla9 or une 11b 1000 .50 1.10 -1h) ! I 200 .70 I .95 1.30 _8.00 g oner n.pa m brt., ribbed. PVR LOA .am1Ú ara sin. .ny elpntmmital Ternis: FOB Cambridge. Mass. I 100 300 .90 1 1.25 1.70 aun 111 51.99 Send check or Money. Order. Include t 1 ,..t r.11.í nt., steno 200 1.75 Postage. Average .'I. per package 400 1 1.20 1 1.60 2.10 1.2.00 . -J, .4. Ib. No C.O.I).s. Minimum Order .c r: 500 1 1.50 1 2.00 1 2.50 I 1 2.25 14141S 1 -- I nu cons.. of two M- 300 $9.00 yatt transistors, Ord 600 1.80 2.40 13.00I 16.00 400 I 2.75 diodes. w;.. I l tor. clo on e w. WE LEAD THE WAY aluminum 1 I tinned Ideal b as 700 2.20 1 2.80 500 1 3.25 AND QUALITY motor speed umool, 141W. 1 IN SERVICE Mass. tall ,.,,th Oler }MOO $491 Send for our latest catalog featuring Transistors and Rectifiers: 325 Elm St.. Cambridge. - ORDER FROM AO -WRITE FOR FREE CATALOG Include Motley Fer P Money Back G SURPLUS CENTER ALES Tel. (617) 547 -4005 ' DEPT. RE -080 LINCOLN, NESS. 1151)1 i Circle 87 on reader service card AUGUST 1970 75 INTERNATIONAL Frequency meter Tests Predetermined Frequencies 25 to 1000 MHz Extended Range Covers 950 MHz Band Pin Diode Attenuator for Full Range Coverage as Signal Generator Measures FM Deviation

MOBILE FM- 2400CH

The FM- 2400CH provides an accurate frequency standard for testing and adjustment of mobile transmitters and receivers at predetermined frequencies. The FM- 2400CH with its extended range covers 25 to 1000 MHz. The frequencies can be those of the radio frequency channels of operation and /or the intermediate frequencies of the receiver between 5 MHz and 40 MHz. Frequency Stability: ± .0005% from +50° to +104°F. Frequency stability with built -in thermom- eter and temperature corrected charts: .00025% from +25° to +125° (.000125% special 450 MHz crystals available). Self- contained in small portable case. Complete solid state circuitry. Recharge- able batteries.

FM- 2400CH (meter only) $595.00 RF crystals (with temperature correction) 24.00 ea. RF crystals (less tern - perature correction) 18.00 ea. IF crystals catalog price

INTERNATIONAL

CRYSTAL MFG. CO., INC. OKLA. CITY. OKLA. 73102 WRITE FOR CATALOG 10 NO LEE J Circle 88 on reader service card 76 RADIO -ELECTRONICS SEE THE DIFFERENCE

IUNIIIJE

the This tuner contact has This tuner contact has been been sprayed with an sprayed with new ordinary tuner cleaner. TUN -O- BRITE. It looks clean, but with its built -in brighteners. heavy duty close examination would It is not only clean. reveal minute areas with it has been polished shiny. corrosion and dirt. There is absolutely no dirt or corrosion left to spread. tuner spray What's more, the contact is protected by a film of ultra -long- lasting lubricant. with FEEL THE DIFFERENCE The extra heavy duty lubricant used in TUN -O -BRITE makes any tuner slide from channel built -in to channel smoothly. Your customer will feel the difference immediately. When he sees bright, clear pictures on every channel and PROFESSIONA polishing Ty S feels how smoothly the channels TECHNICIAN change. he'll know you've done something almost miraculous Ñ N1 11 Ól to his tuner. action! ()LASHINGY AC

MNATES CALLTB . NON FIYMI1_, BT-8 8 oz. $2.39 _ --N BT-16 16 oz. $3.49

FROA S P RAY $471 110--- N E R VALUE

K IM SAVE $478 plow), PAC THAN 98 MORE s MILLION NM-0-BRITE ,) BUY 4 NEW FREE! Tv SETS TMS4 EAST YEAR. YOU GET 2 TUN-O-FOA WHEN scar For NORM TuNSwf

BUY THIS duty tuner The heavy spray with built-in A CTION! 6 -PACK! POLISHING 001 piIw Two MVO F K.o.T ACn . AVAILABLE FROM YOUR 1100111 P°¡s 111 CHEMTRONICS DISTRIBUTOR i urR n 1260 CHEMTRONICS c" N. Y. 11236

Circle 89 on reader .service card The brilliance of our new color replacement tube is matched only by the sharpness of its pictures RCA MATRIX Now it's easier to sell up to the best. RCA RCA's history. Matrix owners can turn up brightness has added brightness without sacrificing without "turning down" color! sharpness! Will your customers see the difference? You bet! Here's0 how and why: What's more, they'll be pre -sold on the difference - To produce the brightest color picture tube in every time they see the 1970 big -screen color sets RCA's history, we developed a new phosphor -dot people are talking about! So when they need a re- screening process that incorporates a jet -black placement tube, satisfy their appetite for brighter, matrix. But we didn't stop here. We wanted a tube sharper pictures. Give their sets new trilliance and that could deliver sharp, vivid pictures even in more vividly detailed pictures with RCA Matrix. The strong room light. So, we added the brilliance of Matrix Tube is 100% brighter than any previous new phosphors and deposited each red, green and color picture tube manufactured by RCA. blue phosphor-dot within the black matrix. Result: For complete details, call your brighter pictures with no loss of contrast. Thanks to RCA L)IStndutor. the matrix technique, combined with our new high RCA Electronic Components, resolution gun and greatly improved phosphors, the Harrison, New Jersey Matrix is also the sharpest color picture tubo in ERILD'M

The RCA 25BCPn Marrez Tube can directly replace 25XP22. 25BA22 and also the tolbwinç tyres: 25A3P22, 25AFP22 25ANP22, 25'P22, 25AP22A, 25A0P22, 25BMP22, 25CP22, 25CP22A, 25GP22, 25GP22A, 25SP22 25W2;, 2EXP2: /25AP22A aid 25ZP22.