Medium wave range booster (CB21677E)

This circuit is from a 1960 book by Hugo Gernsback. The transistors are germanium from the time.

Wien Bridge Oscillator (CB9040E)
This circuit has a frequency range of 30 Hz to 100 kHz with an output signal of 1 Vrms. We found...
AC Phototransistor (CIR812E)
This circuit is suggested by the Optoelectronics Sourcebook by Texas Instruments when AC signals...
Traffic Light (CB21013E)
This sequential relay actuation system circuit for traffic lights was found in Electronics Now...