Found in an 80's Elektor, this circuit can use any equivalent optical coupler. The buzzer is of the Sonalert type with included oscillator.
We published this circuit in a magazine of the 90s, but it is still present by the components it...
The circuit is from the 1990 Motorola Linear Databook, but can be implemented with other operating...
This circuit was found in the January 1996 issue of Electronics Now magazine. The circuit is...