| The frequency is given by 1/2piRC, where R is 10.5k is this
circuits and C is 0.015uF. The oscillations are generates by a specific gain of the
op-amp, that is the same as the losses in the wein bridge circuit. The gain is typically
of 3, but we have to put some compensation in the feedback to be sure that the
oscillations doesn't stop. I think that here it's the 2 diode's, but it's the first time I
say something like that. Most of the time it's a J-Fet that make the job. |