This circuit is from General Electric from the 80s, using a relay with high current contacts (20 A). The transistor admits equivalent, and any phototransistor can be used as a sensor.
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...