rf oscillator circuit

[yalect]

Hello,
I would like to ask you how this oscillator works? and crystal has to shift phase 180 degree to pevent negative feedback?
thank you

[paul@yahrprobert.com]

No, the crystal run in series resonance mode.  That is, at a particular frequency it has a purely resistive impedance.  The transistor provides the 180 degree phase shift, that is the collector voltage drops when the base current rises.

[yalect]

Hi,
thank you
but how that oscillator works where must it has positive feedback and phase shift, maybe quertz has phase shift and what is it? 
thanks
 

[iMo]

It is the Pierce oscillator. The crystal and parasitic capacitances create the 180deg phase shift. Near its resonance freq the crystal in that circuit is equivalent to a C-L-C (pi network) resonant tank.

[yalect]

Thank you
phase shift is 180 degree? And Crystal make it ?
Thanks

[lordvader88]

Here's what I studied today


I need to try the AC analysis on a metal I'm made today