The Colpitts oscillator was regarded as being the most stable
oscillator, which is why it probably was always there, and it was indeed
on my test in the mid-60's. But the Hartley oscillator was also on my
test if I remember correctly, as was the tuned-plate tuned grid
oscillator. If I remember correctly, I had to identify each of at least
three oscillator types. The series tuned Colpitts (aka Clapp
oscillator) might have been there ... maybe the Pierce crystal
oscillator also. I remember that I was required to be able to tell a
bunch of them apart.
Dave AB7E
On 4/27/2020 11:03 AM, Fred Jensen wrote:
What was it with the FCC and the Colpitts oscillator schematic on the
exams in the 50's/early 60's? It was on my General ['54] and Extra
['56] exams, and practically everyone else I've asked says it was on
theirs too. There are other oscillator circuits of the day. Colpitts
uses capacitive feedback which is somewhat more stable than a Hartley
with its "Tickler Coil," but the FCC seemed fixated on the Colpitts
for some reason. The schematic and operation of a dual-triode 1-shot
was also popular.
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
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