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:
Jul. 11, 1978
Filed:
Feb. 04, 1977
Roy Stockdale, Huntington, NY (US);
Lance Weston, Babylon, NY (US);
Napco Security Systems, Inc., Copiaque, NY (US);
Abstract
The alarms circuit provides a first signal indicative of a fire alarm and a second signal indicative of another intrusion such as a burglary. The circuit includes a high frequency RC oscillator which undesireably possesses a duty cycle different from fifty percent. The oscillator output is divided by a bistable multivibrator to produce at an output, a divided signal having a fifty percent duty cycle for application to a loud speaker to energize the same efficiently due to the proper duty cycle. In a burglary mode, the oscillator frequency is modulated by a sawtooth developed by a second bistable multivibrator to provide a wailing tone signal indicative of a burglary. This signal is also divided to produce a proper duty cycle signal for application to the loud speaker.