RTTY Demodulator (CB21760E)

This circuit was found in a 1977 radio amateur manual. Integrated circuits are operational amplifiers of the time.

Triac and UJT Dimmer (CB857E)
This high power dimmer uses a unijunction transistor to trigger the triac. The triac is choosen...
327 Hz High Pass Filter (CB13506E)
This frequency corresponds to musical note C3. Frequency accuracy depends on the accuracy of the...
Transformerless power supply (CB21159E)
This transformerless power supply uses an SCR as a regulator. It was found in a Popular...