Patent ID: 7649437

Claim:
A multilayer positive temperature coefficient thermistor comprising: a ceramic body in which semiconductor ceramic layers having a sintered density in a range of 65% to 90% of a theoretical sintered density and internal electrode layers are alternately laminated to each other; and external electrodes formed on two end portions of the ceramic body and electrically connected to the internal electrode layers, wherein a BaTiO 3 -based ceramic material is a primary component in the semiconductor ceramic layers, the ratio of the Ba site to the Ti site is represented by 0.998≦Ba site/Ti site≦1.006, and at least one element selected from the group consisting of La, Ce, Pr, Nd, and Pm is contained as a semiconductor dopant in the semiconductor ceramic layers, and a thickness d of the internal electrode layers and a thickness D of the semiconductor ceramic layers satisfy d≧0.6 and d/D<0.2.