This 1968 documentation circuit uses a relay to control loads up to 1 kW (depends on relay contacts). The supply voltage depends on the relay.
This is one of the many approaches we have on the site for this low power 0.5 W amp using the...
This circuit was obtained from an American documentation from 1976. The circuit can be adapted to...
This circuit uses a photocell as sensor and a sensitive relay according the power supply voltage....