Page 92 - Analog Circuit Design Art, Science, and Personalities

Bob Pease

the P2, because I know he has one in his lab. (Meanwhile, I agreed to write a chapter
for Jim’s book, and to support and encourage the book, because I want to read all
the other stories that will be in here.)

Vignettes: Additional Little Stories about the P2

One time Bob Malter came back from the big WESCON show in Los Angeles. He
said, “I made a good bargain for a new spec on the piston capacitors. I got the price
down from $2.15 to $1.65. That savings will pay for my trip and then some.” It
sure did.
One time, there were some P2s that had a lousy tempco. Most of the units had a
drift much better than 6 mV from 20 to 45 “C. But this time a couple batches had a
lousy yield for drift. So Bob figured out where to install some little thermistors-
across one of the legs of the 50 k pot-and his wizardly technicians delved away
like mad, and trimmed and tweaked and tested, and sure enough they got the drift
to improve enough to meet specs. I said “delved,” because they had to dig through
the room-temperature-vulcanizing (RTV) potting material to access the places they
needed.
One time, just a couple days after Bob went on vacation, the frequency response
began to go to pot, and none of the usual tricks would fix it. So the senior technician,
Tom Milligan, got on the phone to Bob (who had given him his vacation phone num-
ber), and Bob figured out a tweak, and by the time Bob got back from his vacation,
the problem was completely cured.
One time, I was standing around in front of the Philbrick booth at the big IEEE
show in New York City. A couple engineers were hiking past the booth, and one
said to the other, nodding his head toward the booth, “. . . and there’s the company
that makes a big f- - - - - - profit.” Well, at that time George A. Philbrick Researches
was indeed making big profits from the P2. Can’t deny it.
On various occasions, customers would ask about how to get the best long-term
stability of the offset voltage. It turns out that most parts, if held at a constant tem-
perature, could hold an offset voltage better than 100 FV/hour, and some were as
good as 20 pV/hour. We had our little Rustrak meter to prove it. Heavens, we used

Figure 9-4.
It was what was
inside that was
important!

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