The purpose of this circuit is to monitor the output voltage of a power supply. The under and over voltage indicator was found in the August 1991 Radio Electronics magazine.
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...