We found this circuit very simple in an old documentation. The relay is high voltage sensitive, but the circuit can be adapted to work with lower voltages than indicated. The audible alarm is a buzzer oscillator.
Using a symmetrical source this circuit reverses the rotation of a small motor through light...
This circuit was obtained from an ancient American documentation, but appears elsewhere in this...
July 2017 - The new Texas Instruments ISO772x digital isolators with a speed of up to 100 Mbps and a...