Oral History – Jerry Suran (Continued)
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Up till that point, silicon
could operate at higher temperatures and so could operate at higher power
levels. We switched the unijunction
over to silicon from germanium primarily to increase the power. Of course, the military was very
interested in getting these devices to operate at a higher ambient
temperature.
Was the military interested
in unijunction transistors?
Yes, they were. As a
matter of fact, we used one in an Apollo simulator later on to generate a
very linear sawtooth wave for a TV output.
Anyway, the types of applications were just exactly what you would
use a thyratron for, in the vacuum tube days. Anything that a relaxation oscillator could do, the
unijunctuion could do. Also, with
the advent of digital electronics, we thought these could be used for
clocks in computers.
Eventually, the silicon
controlled rectifier put it out of business, because the SCR could operate
at a much higher power level.
Initially, they were used together, with the unijunction used at low
power levels for triggering. This
was a combination that interested the power companies a great deal, and
that is one of the reasons, I think, that GE jumped on the unijunction
transistor, and became the leading manufacturer of the device. The unijunction was big seller in those
days and it made a lot of money for GE.
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Oral History – Jerry Suran (Continued)
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How did the original name
for this device, the double base diode, change to the name “unijunction
transistor”?
That’s an interesting story.
For a while, we called the unijunction transistor a double base diode
because that’s the way it was discovered.
We thought we had a tetrode, but in fact we had a diode with two
ohmic contacts, and so it was a “double base diode”. That was descriptive term. But the diode
terminology was a misnomer because it was a three terminal device, and not
a two terminal device, and it had
gain – it was an active device and not a passive device like a diode.
I think around 1956, I was on
an IRE standards committee, or actually, on the IRE circuits committee –
410, the transistor circuits subcommittee.
And most of the people on that subcommittee objected to the
terminology, and were trying to standardize terminology. We all knew that this thing was a
transistor, and not a diode. So,
with pressure from the IRE, I proposed that we call it a single junction
transistor, which obviously then became a “unijunction transistor”, and it
was a unijunction transistor but that was also descriptive as well as
correct , because a transistor was a gain device and this thing had
gain. So I think with IRE
standardization pressure, we switched the name to unijunction transistor,
and there was no resistance within GE or any other company to make that
switch.
Go
To Suran Oral History, Page 7
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