This analog instrument circuit was found in a 1990s William Sheets. The components are common and are only suitable for cars with mechanical switching (platinum).
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...