Found in an 80's Hands On Electronics, this circuit turns on a light when it gets dark and goes out when it gets dark. The circuit can be adapted to use high-brightness white LEDs.
This circuit for audio signals was found in the March 1990 Radio Electronics magazine. The circuit...
The operational amplifiers used in this circuit are old. The circuit is from documentation of the 70's, but...
This circuit was obtained in the publication 101 Electronics Projects of 1979. The circuit can be...