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:
Nov. 27, 1984
Filed:
May. 20, 1981
Matsushita Electric Industrial Co., Ltd., Kadoma, JP;
Abstract
The automatic temperature control device for an electric appliance such as an electric blanket comprises a heater element, a sensor made of a thermosensitive material having an impedance, which changes as the temperature varies, for detecting the temperature of the heater element, switching means for regulating the supply of electric power to the heater element, and a plurality of electric circuits for driving the switching means in response to the output signal from the sensor. The plurality of electric circuits function to prevent the sensor from being polarized and to detect a temperature signal by applying thereto an alternating current, to detect a failure occurring in the electric circuits in synchronism with zero-crossing pulses, and to detect a failure occurring in the switching means, thereby assuring a safe operation of the automatic temperature control device against the occurrence of any failure.