This circuit was obtained in a French documentation from 1981 and can be easily assembled. The analog instrument itself can be replaced by the current scale of an ordinary multimeter.
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...