Metal locator (CB7506E)

This simple metal detector was found in a 1960 Sylvania transistor manual. The phone must be high impedance or crystal.

Absolute Value Amplifier CA3140 (CB13841E)
This circuit is from the 1977 RCA Linear Integrated Circuits Manual. The circuit has a...
IR remote control emitter (CB7020E)
This circuit was found in 1980's Radio Electronics. The circuit produces a 1500 Hz modulate 35 kHz....
Triac Power Switch (CB25074E)
The maximum power of the controlled load depends on the triac used. The circuit is from a Radio...