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:
May. 28, 1991
Filed:
Jan. 30, 1989
Robert M Cadwell, Los Altos, CA (US);
Dresser Industries, Inc., Dallas, TX (US);
Abstract
A method and apparatus for determining the extent of deflections of a movable diaphragm in a capacitive displacement type transducer. The transducer circuit is connected to a three terminal capacitive type transducer, and produces an output which is essentially of stray capacitances, circuit component tolerances and changes, and dimensional changes in the transducer elements caused by temperature changes. This is achieved by providing an output which is representative of the difference in the capacitances of the two transducer capacitors, nominalized by dividing by the sum of the capacitance reciprocals. The output of the transducer circuit thus represents the extent of the diaphragm deflection with all other transducer and circuit parameter variations removed.