This circuit that appears in other points of this section and on this website serves to activate a lamp in the event of a power failure. This version is from 1967 documentation by General Electric.
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...