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 is the basic configuration of an operational amplifier sample & hold circuit. The FET and...
The integrated circuit 4136 consists of operational amplifiers of type 741 in the same enclosure and...
We find this circuit in a 1987 publication. It makes use of comparators constructed around the 741...