Simple touch switch

During the experiment, the author accidentally discovered that the control electrode of the one-way silicon controlled thyristor (MCR100-8) will be turned on as long as it is touched by hand without adding a forward voltage. Therefore, the author designed a simple Touch switch, the circuit is shown in the figure below. Touch the metal piece to open, SCR1 is turned on, and the load is powered to work. Touch the metal sheet to close, SCR2 is turned on, relay J is energized to work, K is disconnected, and the load loses power. After SCR2 is turned off, the capacitor discharges relay J and keeps the relay sucking for about 4 seconds, so the circuit action is more accurate. If you replace the load with a relay, you can control the load that operates with high current. Friends who are interested may wish to give it a try.