With this circuit it is possible to control the intensity of a signal digitally. The circuit is from Radio Electronics from February 1981. The power supply must be 18 V.
This circuit can operate with signals up to 60 MHz using the indicated operational. We found it in...
This circuit takes advantage of the noise generated at the reverse biased junction of a germanium...
Equivalent transistors can be used on this 80's circuit. Any general purpose PNP transistor can work...