We found this circuit in an old American documentation. SCRs can be modern equivalent types. The transformer has a 5 A current, according to the SCRs.
This circuit is temperature stabilized. Modern equivalent transistors can be used, and the power...
This circuit uses an optocoupler to obtain a solid state relay whose power depends on the Triac...
This power step for relay activation was found in the 1964 RCA transistors manual. The circuit is of the...