A non-contact displacement sensor based on the theory of magnetic field measurement is introduced.The sensor chooses the strongmagneto metallic membrane resistor as the sensing element

and the non-contact displacement measurement is realized through measuing the change of the magnetic intensity in different displacement.The structure and measuring principle of this sensor is discussed in detail

and the calibration experiment is done.This displacement sensor has simple structure

high SNR

good repetition and can realize non-contact measurement.It widely used in the occasion of serious enviroment and at the same time high measuring precision and reliability are needed.