Oscillator coil sensing head for contactless inductive proximity switch

摘要

A contactless inductive proximity switch contains an oscillator which is formed of a parallel arrangement of an oscillator coil and an oscillator capacitor connected to an integrated circuit. The oscillator coil is provided with a relatively few number of wire turns so as to occupy a relatively small portion of the volume in the cup core. The capacity of the oscillator capacitor is selected to match the oscillator coil. A hard water is retained within the cup core by a casting resin, and protects the oscillator coil from damage.