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:
Oct. 01, 1985
Filed:
Apr. 28, 1983
Applicant:
Inventors:
James E Anderson, Ontario, CA;
Michael J Coleman, Ontario, CA;
Frederick C Livermore, Stittsville, CA;
Assignee:
Northern Telecom Limited, Montreal, CA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02H / ;
U.S. Cl.
CPC ...
361119 ; 361 56 ; 361111 ; 361124 ;
Abstract
An overvoltage protection device, for protecting communications equipment against hazardous voltages cue to lightning or power surges, comprises a primary protector, for example a gas tube device, and a back-up protector connected in parallel. The back-up protector includes a semiconductor pn junction, and is preferably a pair of diodes back-to-back. The back-up protector has a breakdown voltage slightly higher than that of the primary protector and is arranged to fail short-circuit once it has operated so as to provide an indication that the primary protector failed to operate.