We found this circuit in an American 1980s documentation. The circuit uses a piezoelectric transducer unusual in our day. The transistor is general purpose type.
A complete test for opto-couplers can be made using the circuit Bellow. The function generator...
The 50 kHz signal generated by this circuit is applied to a low impedance inductive transducer. A...
This circuit was found in a 1980s documentation. The operational amplifier is of a common type at the...