Motorcycle headlight monitor (CB9117E)

This simple circuit was found in Popular Electronics from the 1980s. The circuit uses an LED as an indicator.

Audio Oscillator (CB10844E)
This circuit was obtained in a 1979 101 Electronics Projects. The circuit can be assembled easily,...
Hysteresis compensator (CB7980E)
Suggested by a 90's Linear Databook, this circuit compensates for capacitor hysteresis. The main...
Analog Isolator (CB13571E)
This circuit serves to isolate analog signals, for example, audio signals in a secure link...