This stereo circuit is from Japanese 1960 documentation. The circuit was originally designed to work with a tube amplifier, removing power from it. The transistors are germanium.
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...