Wednesday, 18 February 2015


A Proximity Sensor is sensor able to detect the presence of nearby objects without any physical contact.
A Proximity sensor often emits electromagnetic radiation , and looks for changes in the field or return signal.

Operating Principle of Proximity Sensor :-

A high frequency magnetic field is generated by coil in the oscillation circuit. 

When a target approaches the magnetic field , an induction current flows in the target due to electromagnetic induction.

As the target approaches the sensor , the induction current flow increases , which causes the load on the oscillation circuit to increase.

Then oscillation attenuates or stops. 

The sensor detects this change in oscillation status with the amplitude detecting circuit , and outputs a detection signal.

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