This circuit was found in a Hands On Electronics from the 90s. It is intended to supply old tape players to batteries with a voltage of 7.5 V from the 12 V of a car battery or source.
This circuit is temperature stabilized. Modern equivalent transistors can be used, and the power...
This circuit uses an optocoupler to obtain a solid state relay whose power depends on the Triac...
This power step for relay activation was found in the 1964 RCA transistors manual. The circuit is of the...