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.