Barkhausen criteria in multivibrators

[matbob]

Hi,

My question may be absurd but can anyone tell me whether we can apply Barkhusen criteria for astable multivibrators? If it is possible,how?

 

[LvW]

Hi,

My question may be absurd but can anyone tell me whether we can apply Barkhusen criteria for astable multivibrators? If it is possible,how?

No, you can't.
The reason is simple: The Barkhausen oscillation criterion is based on the loop gain of a circuit with feedback. Any "gain" by definition is a small signal parameter which is valid in the vicinity of an operating point located on a linear (or linearized) portion of the transfer curve.
Multivibrators are strong non-linear circuits which are switched between two extreme values.

(Hint: But I should add that by redesigning the feedback path of a multivibrator the whole circuit can work as a linear oscillator with sinusoidal signals by exploiting the frequency dependent gain of the opamp. But this is beyond your question. Anyhow, this is a very interesting property of the multivibrator structure)