This is the circuit of an automotive voltage regulator from the 1970s. The circuit is entirely electromechanical based on the closing of a relay contacts according to the voltage.
This 80's circuit uses a germanium transistor like the AC121. The circuit has an output...
This circuit is from the Motorola Linear Databook of 1990. The circuit controls a Triac from a...
I found this circuit in a Popular Electronics from 1992. The circuit shows how we can receive...