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 circuit triggers an alarm when the mains power is cut off. The circuit was found in the July...
This acutely tuned circuit was found in American documentation from the 1960s. The transistors are germanium...
This small AM transmitter was found in American documentation from the 1980s. Transistor support...