Volume expander amplifier (T364E)

This circuit was found in the 1961 RCA tube manual. The circuit includes a power supply stage.

Battery controlled switch (CB8708E)
This circuit was found in a 90s Popular Electronics. It can be used to control a triac from the...
Flasher (CB22498E)
Originally designed for an incandescent lamp, this flasher or pulser can be adapted to operate with...
Simple Metal Detector (CB11508E)
This circuit found in Popular Electronics from July 1974 consists of an oscillator that sends its...