This circuit was found in General Electric documentation from 1964. It makes use of a PUT, called the PNPN planar key at the time. The circuit has two supply voltages.
This conventional configuration of source stabilized with zener and transistor was found in a...
This RS flip-flop uses two type 4N26 optical couplers and is characterized by the very high...
This is a direction of rotation control for a small motor up to about 2 A with the indicated...