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 presented is based on a mechanical tuning fork. The circuit is suggested by National...
This source, from a 1982 documentation, uses a triac to control the power and voltage applied to...
This circuit was found in a 1990 Electronics World magazine. The circuit can be mounted today by...