Transistor Museum Lecture Hall

Mr. Thomas Stanley

 

The First RCA Transistor Radios

by Thomas Stanley

 

Point-contact transistors were inherently unstable, as was the radio we breadboarded to use them, since it depended on regeneration to achieve adequate gain. As Loy put it, "Stage gain was long about 70 db, just before it oscillated." Since gain increased as temperature dropped, if the radio was working inside, it would go into oscillation when we took it outside where the reception was better but the air colder. Worth noting in passing was that our boss, Lanky Carlson, contrived for personal use perhaps the first TV remote control: a long bamboo pole with a rubber suction cup at its tip.

 

After several trainee stints, I was accepted in Al Barco's group. We, like almost everyone at RCA then, were working feverishly to gain FCC acceptance of the RCA compatible color television system, displacing the CBS incompatible whirling disc system then in place. But soon, Larry Freedman, Dave and I were laboring under Al's uncompromising eye on transistor applications, and intimately dependent on the ingenuity, skill and cheerful collegiality of such as Charlie Mueller and Dietrich Jenny and the dedication of Ethel Moonan who conjured up the transistors. Sometimes they learned from us as we flogged the transistors to performance in excess of what seemed reasonable. Al Barco, having been told early on, that he mustn't exceed fifty milliwatts dissipation in testing some very early alloy junction transistors, took matters in his own hands.

 

 

 

 

 

The First RCA Transistor Radios

by Thomas Stanley

 

He irreverently filed back a third of the epoxy encapsulation, exposing the collector dot, to which he soldered an inch-square copper fin. It was possible, then, to test the transistor up to half-watt dissipation. Soon the transistor makers devised their own heat dissipating packages. This was easier for the soft indium dots of the PNP's than the brittle lead-antimony of the NPN's. Diet Jenny's solution, packaging his power NPN's in little tin cans containing toluene, was abandoned when the packages exploded, sending the tin cans whistling past the researcher's ear. (See page 4 of this presentation for a photo of the PNP TA-153 and the NPN TA-154 transistors).

Junction transistors were perceived to be mysterious and novel. They were said to amplify current, rather than voltage, like vacuum tubes. It behooved us to postulate equivalent circuits-- folks conversed knowingly about R-B-B-prime. My first exposure to Bill Webster was to hear him being less than entirely respectful to sage pronouncements about equivalent circuits at a section meeting. Soon, though, an amalgam of physics, electrical engineering and common sense evolved, and with it, progress in both circuit and transistor design. Bill explained the physics of the drop-off in injection efficiency at the high currents we needed; Loren Armstrong laced his indium emitter dots with gallium and things improved.

 

Go To Stanley, Page 3

COPYRIGHT 2001 by Jack Ward. All Rights Reserved. http://www.transistormuseum.com

PAGE 2