This Schmitt optical trigger with LDR was found in old documentation. The relay must be sensitive, or an additional step must be used to trigger it.
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...