This circuit works like a solid-state contactor. We find it in General Electric documentation from 1965. SCRs can be modern equivalents according to the controlled load.
This circuit was found in an old English publication. The circuit makes use of general-purpose transistors....
This experimental receiver works with alternative sources of energy or a single cell of any type....
This circuit is from a NEC megaphone made in Japan in the 60s. The circuit has 4 W of power and...