Mini Organ (CB21653E)

This toy organ was found in Popular Electronics from January 1967. It can be constructed from modern equivalent transistors.

Light Activated Switch (CB14457E)
This circuit is from 1968 documentation. We can assemble it with more modern components such as a...
Speaker protection (CB8193E)
Found in a 90s Silicon Chip documentation this circuit is intended to protect a speaker system in...
UV Sensor with UVTRON Tube (CB25942E)
The UVTRON tube is an ultraviolet radiation sensor. In this circuit from Radio Electronics from...