The working principle of InSb magnetoresistive proximity switch is introduced.The signal processing circuit is designed and the dynamic characteristics is measured.The experimental result shows that the action-distance of the proximity switch is more than 8 mm when the radial distance is 4 mm.The hysteresis-distance can be limited in 0.06 mm.The repeating location precision is prior to 0.04 mm.It can be used for ferromagnetic substance measuring of working frequency from 0 to 5 kHz.The proximity switch has high sensitivity

fine dynamic characteristics

simple construction and low cost.It can be produced for a large scale.