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.
The circuit in the figure indicates when the input voltage exceeds a certain value adjusted by the...
We found this circuit in Radio Electronics magazine from May 1962. The circuit uses rectifier...
This circuit, from a 1974 publication, can be assembled with BC548 transistors. If powered with 6 or...