This circuit is from a 1965 Motorola manual. It can be implemented with a common 2N2646 and a 106 Series SCR without problems. The pulse transformer has a 1: 1 turn ratio.
This circuit was found in a 1968 General Electric documentation. It has an input impedance of 2 M ohms...
This circuit shuts off and locks the power to a load in the event of a failure. The circuit is from...
This circuit is from 1995 documentation, but can be easily assembled today, as the components used are...