Electronic key for mains voltage switching - can be connected in parallel with other electronic or mechanical switches

摘要

The electronic key is interchangeable with mechanical keys, and can be connected in series with a common impulse relay whose contact switches mains voltage on and off to or from the load. The idling current of each electronic key is negligibly small, so that the sum of all idling currents is smaller than the impulse relay holding current. It is also negligible in comparison with the current consumption of neon lamps. It comprises a rectifier bridge whose a.c. input is connected to the impulse relay, and d.c. output to the transistors connected in parallel. A second transistor emitter is connected through a resistor to the first transistor base, and through a capacitor and a rectifier bridge arm to a mains phase. The second transistor base is connected through a resistor to a contact plate.