common collector colpitts oscillator?

Thread Starter


Joined Nov 23, 2006
Hi everyone. I have some questions about the CC colpitts oscillator.
Most books say the CC oscillator is very rare to use, and the cc
configuration is usually used for impeadance matching(high in- low out)
or buffer amplifier.But I find that some uhf PNP transistor is designed for CC oscillator.(and the datasheet emphasizes the the term "for common collector")
What is the purpose to use common collector configuration rather the
common emitter configuration?
Anyone knows the basic diagram for CC colpitts oscillator?


Joined Apr 20, 2004

Common collector transistors have gains of less than unity. Oscillators have to have gains graeter than unity in order to oscillate. So a common collector colpitts oscillator seems more trouble than it is worth.

Got a number for that UHF PNP transistor?


Joined Jun 29, 2010
Microchip has a very good application note on oscillators: AN826
Crystal Oscillator Basics and Crystal Selection​
for rfPIC
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