This protective circuit for power lines was found in a Radio Electronics from November 1957. The transistor used can be any general-purpose transistor such as the CK722.
This audio oscillator operates like a signal injector in a frequency given by C1. The circuit was...
This crystal-controlled oscillator was found in the January 1994 issue of Electronics Now. Other...
In this circuit the frequency is determined by the coil and the variable capacitor. Transistors like the...