Hi,
I am we got one circuit for Wien bridge Oscillator. Trying to evaluate. Created file in TINA, but not able to see 500KHz o/p.
What could be purpose of RC series switched through FET. FET is applied with 500KHz pules of 0 to -14V
Regards,
Amod
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Hi,
I am we got one circuit for Wien bridge Oscillator. Trying to evaluate. Created file in TINA, but not able to see 500KHz o/p.
What could be purpose of RC series switched through FET. FET is applied with 500KHz pules of 0 to -14V
Regards,
Amod
Hello Amod,
I simplified the circuit to make it functional. Below is a 700 Hz Wien Bridge Oscillator. I have attached the simulation. You can see that the JFET controls the oscillation either being active or inactive. If the voltage at the gate is 0 V then there is a DC path to ground. If the voltage at the gate is -14.98V then the JFET is closed and the path to ground is cut off. I believe this is the purpose of the JFET although I had to eliminate the capacitor that was in series with the drain to obtain this functionality.
As an additional resource we have an Application Note that covers the Wein Bridge Oscillator as well.

OPA1611 Wien Bridge Oscillator.TSC
Best Regards,
Chris Featherstone