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:
Nov. 23, 1993
Filed:
Apr. 23, 1991
Kenneth C Radford, North Huntingdon, PA (US);
Robert G Johnson, Bloomington, IN (US);
Andrew S Sweetana, Jr, Bloomington, IN (US);
Electric Power Research Institute, Inc., Palo Alto, CA (US);
Abstract
A method of manufacturing a varistor utilizes preselected amounts of ZnO which are combined with specified amounts of additives including B, Na, Bi.sub.2 O.sub.3 and BaO to form a variety of compositions. Each composition is pressed into a disc. The disc is then sintered at a first selected temperature. Afterwards, the disc is annealed at a second selected temperature. The specific compositions disclosed render a varistor with improved high temperature performance when the annealing step is followed with a low temperature tempering cycle at approximately 250.degree. C.