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The
First RCA Transistor Radios
by Thomas Stanley
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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.
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The
First RCA Transistor Radios
by Thomas Stanley
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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
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