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:
Jan. 13, 1976
Filed:
Jun. 24, 1974
Stanley B Welch, Louisville, KY (US);
General Electric Company, Louisville, KY (US);
Abstract
A self-contained, temperature responsive alarm control circuit uses a battery as an energy source. A solid state, free-running multivibrator provides a square wave of audio frequency which provides the pulse to turn on an emitter follower also at an audio frequency so as to energize a Wheatstone bridge across the battery at the same audio frequency. One of the legs of the Wheatstone bridge includes a temperature sensitive thermistor. A programmable unijunction transistor serves as a threshold detector for the bridge circuit which, upon its being gated into conditon upon the reaching of a predetermined, preset temperature sensed by the thermistor, provides a signal to turn on an audio amplifier at the same audio frequency thereby to energize a speaker now essentially coupled across the battery to produce an audible sound.