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:
Jul. 02, 1991
Filed:
Jan. 18, 1990
Robert M Cadwell, Los Altos, CA (US);
Dresser Industries, Inc., Dallas, TX (US);
Abstract
A method and means for determining the deflection of a movable element in a transducer by measurement of capacitance. The result is independent of extraneous capacitance between the transducer terminals and the environment, of the magnitude of the transducer capacitance, and of scaling factors within the measurement circuits. The difference and sum of differential capacitances are determined, preferably independently of their individual values, using switching techniques and a common measurement circuit. The ratio of differential capacitances is determined by causing the measurement signal for one capacitance to be inversely proportional to the magnitude of the other capacitance.