Capacitive proximity sensor

U.S. Patent Number: 5315884

Abstract: A proximity sensor based on a closed field circuit. The circuit comprises a ring oscillator using a symmetrical array of plates that creates an oscillating displacement current. The displacement current varies as a function of the proximity of objects to the plate array. Preferably the plates are in the form of a group of three pair of symmetric plates having a common center, arranged in a hexagonal pattern with opposing plates linked as a pair. The sensor produces logic level pulses suitable for interfacing with a computer or process controller. The proximity sensor can be incorporated into a load cell, a differential pressure gauge, or a device for measuring the consistency of a characteristic of a material where a variation in the consistency causes the dielectric constant of the material to change.

Inventors: Kronberg; James W. (Aiken, SC)

Assignee: The United States of America as represented by the United States (Washington, DC)

Application Number: 07/756,669

Issued: 1994-05-31

Expired: 2006-05-31

Classes: 73/862.68 ; 324/671

Field of search: 73/862.626,862.68,718,724 29/25.25 361/283 324/658,671,674,675,681,661,662,690,677,678 340/562,563

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