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:
Dec. 20, 1977
Filed:
Jul. 19, 1976
Applicant:
Inventor:
Roy Stockdale, Huntington, NY (US);
Assignee:
Napco Security Systems, Inc., Copiague, NY (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340411 ; 3402 / ; 340276 ;
Abstract
An automatic test circuit for a photo electric intrusion system incorporates an electronic attenuator which serves to reduce the sensitivity of the receiver when a light beam does not impinge on a photocell located at the receiver. As soon as the light beam appears on the photocell, the sensitivity of the receiver is increased to a normal operating value. In this manner, if the beam were misaligned to cause less light to impinge on the photocell, the receiver would indicate an alarm condition to thereby inform a user of the problem.