This circuit is from a Radio Electronics from April 1964. The circuit uses power transistors of the time, which must be mounted on a good heat radiator. Modern equivalents can be used.
This circuit is from 1968 documentation. We can assemble it with more modern components such as a...
Found in a 90s Silicon Chip documentation this circuit is intended to protect a speaker system in...
The UVTRON tube is an ultraviolet radiation sensor. In this circuit from Radio Electronics from...