This configuration can be found in several articles on this site. The one shown in the diagram is from the datasheet of the LM101 series amplifiers, but it can be implemented with other types.
This plug-in control was found in General Electric documentation from the 1970s. The SCR can be...
This circuit digitally selects the inputs of a sound system by applying its signals to the...
Found in 1965s General Electric documentation, this circuit is intended for the control of servos...