Abstract: A noncontact electronic switching arrangement is provided with an oscillator which can be damped by external objects. In accordance with the invention, the oscillator can be excited externally and is coupled to an evaluation circuit and an amplifier. A frequency control, which may consist of a phase-locked loop module, is connected to the externally excited resonant circuit of the oscillator. A reference voltage comparator at the output of the oscillator delivers at a Schmitt trigger output, pulse signals to a retriggerable time delay stage, or a shift register, which are connected to an exclusive-OR stage. The functioning of the exclusive-OR stage can be programmed. The arrangement is particularly useful as a limit or end switch for machine tools.

Abstract: This invention is of an ultrasonic proximity switch having a range selection control circuit. The range selection control circuit is in this instance separated from the sensor by being installed in a separate housing which can be mounted in the switching unit. It is equipped with a potentiometer in the form of encoding switches and an actual value display which can be designed in the form of an LCD design. In addition, various selector switches can be mounted in the housing.

Abstract: 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.