I am fiddling with this simple colpitts oscillator:
It has a RFC choke in the collector.
I am trying to understand how it works. I assume that :
1. The choke provides LOW impedance path to DC hence allowing quiescent current or operating current for the transistor.
2. The choke acts as high impedance for the ac oscillations at high frequency hence provides gain by acting as high collector resistance for the AC.
Are the above assumptions correct ? or is there more to it ?
However, the RFC choke is an inductor and causes phase shift between the voltage and current.
So with the RFC choke the amplifier is not a strictly 180 degree inverting amplifier ? OR is it ?
If rfc cause phase shift the loop phase shift will not be 0, and the oscillations should not work.
But the above circuit works fine, producing oscillations around 175 Khz.
Am I missing something ?
It has a RFC choke in the collector.
I am trying to understand how it works. I assume that :
1. The choke provides LOW impedance path to DC hence allowing quiescent current or operating current for the transistor.
2. The choke acts as high impedance for the ac oscillations at high frequency hence provides gain by acting as high collector resistance for the AC.
Are the above assumptions correct ? or is there more to it ?
However, the RFC choke is an inductor and causes phase shift between the voltage and current.
So with the RFC choke the amplifier is not a strictly 180 degree inverting amplifier ? OR is it ?
If rfc cause phase shift the loop phase shift will not be 0, and the oscillations should not work.
But the above circuit works fine, producing oscillations around 175 Khz.
Am I missing something ?