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. 25, 1986
Filed:
Apr. 23, 1984
Northern Telecom Limited, Montreal, CA;
Abstract
An overvoltage protection device, especially for telephone equipment and the like, comprises two protectors connected directly in parallel. One protector, for example a back-to-back semiconductor diode, has a breakdown voltage below which it is a high impedance. Between the breakdown voltage and a failure voltage it has a lower impedance. Above the failure voltage it has negligible impedance. The other protector, for example a gas tube, has a range of operating voltages which extends from below the breakdown voltage of the diode, to a voltage between the breakdown voltage and the failure voltage of the diode. In operation the two protectors interact, the diode operating, for example, on faster surges and, in so doing, slowing the surge front so as to increase the likelihood that the gas tube will fire.