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:
Mar. 16, 1993
Filed:
Aug. 10, 1990
Dennis K Briefer, Berlin, MA (US);
Setra Systems, Inc., Acton, MA (US);
Abstract
A capacitive sensing circuit and system includes a variable capacitance sensing element as an active element in a circuit to measure changes in capacitance of the sensing element. A switching network in alternate cycles energizes a capacitor to develop a charge which effectively linearizes the sensor's capacitance response. In a push-pull circuit with two active sensing elements, a multi-channel switching network energizes two fixed correction capacitors to provide third or higher order correction, significantly extending the effective scale of the sensor. In a preferred embodiment, a single feedback signal is applied to all capacitors in different switching cycles. Examples include weight and pressure sensing systems.