Circuits similar to this can be found in this section. This is from 1967 General Electric documentation. The main SCR must be fitted with a heat sink.
This circuit is from an Electronics World of 1964. The circuit can be made with modern...
We find this circuit in a Radio Electronics of July 1984. It consists of the traditional version of 1 A...
This circuit was found in the June 1990 issue of Radio Electronics magazine. The maximum current is 1...