We found this circuit in the September 1971 Radio Electronics magazine. The SCR can be any of the 106 series and the buzzer can be replaced by a relay according to the supply voltage.
This immobilizer circuit for the car was found in the Radio Electronics magazine of December 1976....
This circuit allows the activation of a remote telephone bell made with a common piezoelectric capsule. The...
This circuit can act as a receiver for the transmitter of the previous circuit. We found it in...