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.
The circuit presented is based on a mechanical tuning fork. The circuit is suggested by National...
This source, from a 1982 documentation, uses a triac to control the power and voltage applied to...
This circuit was found in a 1990 Electronics World magazine. The circuit can be mounted today by...