My family bought a 2-switch lamp with 3 holes in the back, but my family has 4 wires. How should I connect them?

This paper briefly introduces the principle that the unit double control switch controls two places to control one lamp. .

The lighting circuit breaker of indoor distribution box adopts three-wire connection (PE L N now lamps generally need to be grounded).

PE and N are connected to the lamp, and one L line is connected to one of the dual-control switches, and the other two holes are connected to the two holes of the other switch.

Pick up the other end of a double-control switch and pull out the wire to connect it to the lamp. In this way, the control of the two places is realized. .

The principle of the three controls is similar, but more lines are needed. .

I want to understand the principle, coupled with the physical comparison in my hand, the problem is not big. .

If there is a schematic diagram of switch wiring on the internet, you can go and have a look. . Right here (Netease). .