This old circuit (1968) uses a germanium transistor to drive a relazy from a switch. The circuit can also be used as a shield for microcontroler by applying the control signal at the 1 k ohm resistor. Voltage can be 6 or 12 V according the relay.

This old circuit (1968) uses a germanium transistor to drive a relazy from a switch. The circuit can also be used as a shield for microcontroler by applying the control signal at the 1 k ohm resistor. Voltage can be 6 or 12 V according the relay.