What is a dual control switch? Can someone tell me something about it?

A double control switch is a switch with normally open and normally closed contacts (i.e. a pair). Usually, two double-control switches are used to control a lamp or other electrical appliances, that is to say, there can be two switches to control the switches of lamps and other electrical appliances, such as turning on the switch when downstairs and turning off the switch when upstairs.

If you use the traditional switch, you have to go downstairs to turn off the lights, and the double-control switch can avoid this trouble. In addition, the double control switch is also used to control the lights that need to be forced to light in the emergency lighting circuit. Two ends of a double-control switch are connected with a double power supply, and one end is connected with a lamp, that is, one switch controls one lamp.

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