Magnetic field sensor for proximity switch uses thin metal strip with magnetic permeability varying in dependence on magnetic field strength

摘要

The proximity switch determines the voltage (U) across 2 spaced tap-off points (4,5) of a thin metal strip (1) supplied with a HF current (I), made of a material with a permeability which varies in dependence on the magnetic field strength. The HF current is provided by a variable constant current source (6) allowing the thin metal strip to be brought into magnetic saturation. An Independent claim for a magnetically operated proximity switch is also included.