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:
Apr. 15, 1980
Filed:
Nov. 20, 1978
Gamdur S Mann, Flint, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A variable capacitor includes a metal diaphragm arranged to flex in response to an applied pressure differential serving as a movable capacitor plate and a fixed capacitor plate closely spaced from the diaphragm. At least one of the two capacitor plates has an insulating layer of metal oxide formed thereon to prevent electrical contact therebetween. By making the capacitor plate of an iron-chrome-aluminum alloy and heating the capacitor plate, an aluminum oxide layer is formed thereon. The fixed capacitor plate is formed in a hat-shaped configuration with the brim portion spaced far from the diaphragm by an insulating spacer to minimize the fixed capacitance around the edge of the capacitor assembly.