Found in a 1966 Electronics World, this circuit applies to the protection of any analog instrument. The diodes can be of any general-purpose type.
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...