5VDC NPN Inductive Proximity Sensor Detection Switch - Normally Open

Inductive proximity sensors or switches or also known as metal sensors contain high-frequency oscillation circuit, detection circuit, amplifier circuit, the solution circuit and the output circuit. When the power is supplied to the switch, the oscillator in the high frequency oscillation circuit generates an alternating electromagnetic field on the detection surface of the switch.

When there is a metal close to the switch detection surface, the eddy current inside the metal absorbs the energy of the alternating electromagnetic field in the oscillator. The oscillator is weakened or stopped. Oscillator energy changes in the two states, the detection circuit is converted to a level signal, through the amplifier circuit to amplify the level signal after the trigger circuit to trigger the output transistor and the transistor circuit produces a switch signal. Thereby, this sensor detecting the presence or absence of the metal in order to achieve the purpose of metal detection.