Using an LDR as a sensor and an operational amplifier this circuit was found in the Encyclopedia of Electronic Circuits volume 5 from 1995. The circuit triggers an optodiac.
The integrated circuit used is a voltage reference from Motorola. This configuration was obtained in...
This circuit is from a Radio Electronics from October 1970. The circuit uses transistors from that...
This circuit was obtained from a 1977 magazine, but can still be mounted using BC548 for TR1 and...