The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 06, 1991
Filed:
Jun. 26, 1989
Hans Braun, Karlsruhe, DE;
Uwe Kessler, Oftersheim, DE;
Abstract
A capacitive difference sensor includes two sensor electrodes, each of which lies opposite a transmitting electrode fed by an electrical AC voltage source. A circuit arrangment connected to the two sensor electrodes for signal recovery generates a differential signal which corresponds to the difference between the displacement currents induced in the two sensor electrodes. The circuit arrangement includes a series resonance circuit comprising a coil and a capacitor, the resonance frequency of the series resonance circuit corresponding to the frequency of the AC voltage source. The two sensor electrodes are coupled via a transformer in opposite senses to the series resonance circuit and the differential signal is tapped off at the tap of the series resistance circuit formed by the connecting point between the coil and the capacitor.