Patent ID: 6559771
Filing Date: 2003-05-06
Classification: G01N

Abstract:
In combination,(a) a tablet of positive-temperature-coefficient material having a continuously-electrically-conductive first surface and a second surface which is discontinuously electrically conductive so as to separate said second surface into at least a first conductive zone and a second conductive zone which are not in electrical contact with each other except through said positive-temperature-coefficient material, (b) means for electrically energizing said first surface, (c) means for connecting said second conductive zone to a steady level of electrical potential, (d) resistive means for connecting said first conductive zone to a steady level of electrical potential, said resistive means comprising a first resistive segment and a second resistive segment, joined in series through a node, (e) switching means connected to said node, and (f) means for thermally coupling said first conductive zone of said second surface, and the portion of said tablet adjacent thereto, to a heat receptor.