We found this circuit in a 1964 Electronic Design. The triac and SCR can be replaced with modern equivalents according to the load. The circuit is for 160V network.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...