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:
Aug. 01, 1978
Filed:
Oct. 01, 1976
Applicant:
Inventor:
Joseph P Hesler, Liverpool, NY (US);
Assignee:
General Electric Company, Syracuse, NY (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340629 ; 250381 ; 331 65 ; 3311 / ; 331111 ;
Abstract
A smoke detector comprising a smoke detection cell of the ionization type and an electrical network providing for a.c. operation of the detection cell. The impedance of the detection cell changes in the presence of airborne combustion products and alters the operating frequency of the network. The frequency change is sensed to actuate an alarm. A.C. operation avoids the problem of d.c. instability in the high impedance detection cell circuit and simplifies sensing the electrical condition of the detection cell. The electrical network typically uses MOS-FET devices as the active circuit elements.