This circuit was found in the February 1981 issue of Radio Electronics magazine. The circuit uses an active component of the time and is suitable for audio signals.
This simple transistor tester circuit was found in the February 1968 issue of Radio Electronics magazine....
This powerful inverter provides a high-quality sine wave signal. I found it in a Radio Electronics issue...
This squelch is activated by its own noise, acting automatically. It is used in communications...