Proximity sensor principle

First, the principle of proximity sensor - - Introduction

By the "proximity switch" refers to a non-contact manner can be used to detect the presence or absence of objects near the turn of the switch corresponding action products available, "near" mainly refers to a non-contact characteristics, so we can get further "proximity sensor" is actually a no contact can be induced to be measured and convert it to an electrical signal. The proximity sensor can be divided into capacitive proximity sensors and inductive sensors, then we do these principles of the two sensors to detail ~

Second, the principle of capacitive proximity sensor

Capacitive proximity sensor consists of a high-frequency oscillators, amplifiers and other components, wherein the detection surface and ground sensors constitute a large capacitor, start time, no objects near the loop in oscillation state, as gradually close the object, capacity of the capacitor changes, the oscillation is stopped, the oscillation state of this change can be converted into an electrical signal, amplified by an amplifier and converted by the binary signal to the switching operation.

Third, the principle of inductive proximity sensors

Inductive proximity sensors mainly by the high-frequency oscillator, amplifier, detector circuit, the trigger part of the circuit and an output circuit. Start time, high-frequency oscillator for generating an electromagnetic field at the sensor surface, no metal objects nearby, oscillating circuit, with the gradual near metal objects, metal vortex generated gradually absorb the energy of high-frequency oscillator until it stops shaking So far, these two high-frequency oscillator to change the oscillation state can be converted into electrical signals, and by the detector, amplified and converted into a binary signal, and then the power amplifier output.