This conventional relay light detector circuit uses a 741 as a voltage comparator. The sensitivity adjustment is made in R1. The supply voltage depends on the relay used.
This circuit can serve as the basis for a small FM transmitter with varicap. We found it in a...
This circuit was obtained from the Radio Electronics magazine of August 1962. It is a tandem...
This 10 A solid state relay was found in a 1980s documentation. It can work as a shield and...