The selected circuit was found in GE's 1977 semiconductor manual. 3N84 is a controlled silicon switch and SCRs support equivalents. The transistor can be a BC558, depending on the supply voltage.
This control from a 1989 publication can be assembled with several equivalent components. The SCR,...
In the figure we have a circuit suggested by National Semiconductor, using an operational...
This circuit was obtained from an English magazine from 1976. What this circuit does is start from...