The single control switch has only two terminals, and the double control switch has three terminals;

Second, the difference in usage:

Single-control switch means that one switch controls one light, and double-control switch means that the same light is controlled in two different places: the living room and the stairs, so that we don't have to go back to the bedroom in the dark after turning off the lights (the entrance door), which is very convenient.

Extended data:

Double control switch:

A switch has two normally open and normally closed contacts at the same time (that is, 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.

Single control switch:

Single-control switch is the most common in home circuits, that is, one switch controls one or more appliances. According to the number of connected electrical appliances, it can be divided into single-control single-connection, single-control double-connection, single-control triple, single-control quadruple and other forms. If the kitchen uses a single-control single-link switch, and one switch controls a group of lighting lamps, the living room may have three spotlights installed, so it can be controlled by a single-control triple switch.

References:

Single open and double control-Baidu Encyclopedia Double open and double control-Baidu Encyclopedia