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. 09, 1979
Filed:
Sep. 06, 1978
Applicant:
Inventors:
James C Morris, Wakefield, MA (US);
Robert L Garrison, Henniker, NH (US);
Assignee:
GTE Sylvania Incorporated, Stamford, CT (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G08B / ; G08B / ;
U.S. Cl.
CPC ...
3403 / ; 340566 ;
Abstract
An intrusion alarm circuit including a single electroacoustical transducer, such as a diaphragm-supported piezoelectric element, connected to an amplifier in a positive feedback loop configuration. The transducer functions as both a sound pickup and sound generator. When the ambient sound level exceeds a preselected threshold level, the resulting vibration of the transducer generates a voltage which activates the amplifier, whereupon the transducer vibrations are sustained and amplified in the manner of an oscillator, thereby producing an audible alarm.