Found in a 90s Popular Electronics, this circuit excites a 40 kHz ultrasonic transducer. The transistor can be a BD135 or other medium power.
This distortion circuit was found in an American publication from 1970. It can be assembled with...
We found this circuit in a Radio Electronics magazine from January 1975. The transistors are...
Equivalent operational amplifiers can be used in this circuit of the 1990 Linear Databook,...