Raystor is a component of the 1960s Raytheon. It consists of a light coupler that allows you to use the circuit as a DC control for signals as shown.
This circuit was found in a Motorola documentation from the 70s. The components are from the time,...
In this 2001 circuit we have the way to trigger an SCR with a phototransistor. The circuit appears...
Found on an 80's Radio Electronics, this circuit is designed to pass the 300 to 34,000 Hz voice...