Found in a 1969s American documentation, this circuit uses transistors from that time. The configuration can be adapted to use modern equivalent components.
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...