Although it is also a switch, the measurement of this proximity switch is somewhat special. If we measure it directly, we will definitely not be able to measure anything because this proximity switch requires power supply during normal operation, just like an electrical appliance that needs to be connected to a power source, and most of them are 24V DC.

After supplying power to the proximity switch, we also need to understand its internal wiring method. Taking the three wire proximity switch as an example, friends who understand some circuit knowledge can easily see that the on-off of the proximity switch is related to a transistor. When the main circuit of the proximity switch senses an object, it will cause an on-off change inside the circuit. This will form a closed circuit at both ends of the load in the figure, that is, a 24V power supply is added to both sides of the load. This is actually the working principle of the proximity switch.