Found in an 80's Elektor, this circuit can use any equivalent optical coupler. The buzzer is of the Sonalert type with included oscillator.
This circuit is intended for signal amplification of electronic musical instruments. We found in a...
Texas Instruments UCC21225A is available from Mouser Electronics. It is an isolated gate driver...
This circuit can be used as an answering password system in a store, office, or other location....