Tiefenbach Gmbh

Friedhelm Joost

A proximity switch for determining the approach of a metal object includes an oscillating circuit which has a coil and a capacitor, and which produces a high-frequency field at the poles of the coil. A sensing resistor is connected to the oscillating circuit and serves to determine and evaluate the damping of the oscillating circuit by the object. Also, the sensing resistor is controlled as a function of the current measured in the sensing resistor such that the total resistance of the evaluation circuit remains constant. The voltage drop across the sensing resistor is measured and the measured voltage drop may be used to signal the approach of the metal object.

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Essen, Germany

Friedhelm Joost