POSITIVE TEMPERATURE-COEFFICIENT THERMISTOR

摘要

The present invention: reduces the resistance of a positive temperature-coefficient thermistor having an embodiment wherein a thermistor thick film that is a heat source is formed on an alumina substrate; and increases the adhesiveness of the thermistor thick film. The positive temperature-coefficient thermistor (1) is provided with: an alumina substrate (2); a thermistor thick film (3) exhibiting PTC characteristics and formed on the alumina substrate (2); and a pair of electrodes (4, 5) that face each other sandwiching at least a portion of the thermistor thick film (3). The thermistor thick film (3) comprises a semiconductor ceramic sintered body having barium titanate as the primary component and containing at least the element boron as an accessory component. When the ratio of contained atoms of the element boron with respect to one mole of the barium titanate primary component in the semiconductor ceramic is a and the Si/Al atom ratio as the ratio of contained silica with respect to alumina in the alumina substrate (2) is ß, the conditions 0.0015 = a×ß = 0.045, 0.05 = a = 1.5, and ß = 0.2 are satisfied.