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.
This circuit emits an audible signal when the mains voltage ceases. The circuit is from a 1973...
We found this circuit in a 1966 RCA manual. The integrated circuit is unusual, and the Triac must...
Short duration pulses or "clicks" can be generated with the circuit seen in the figure. The...