| 摘要 |
PURPOSE:To generate heating density of a main electrode almost equal to heating density of a PTC resistance film over a predetermined wide temperature range (for instance, -30 to 100 deg.C). CONSTITUTION:The first/second main electrodes 4, 5 are formed in an opposed shape on an insulating substrate 2, and the first/second comb tooth-shaped subelectrodes 6, 7 are respectively drawn out from these main electrodes. The first (second) subelectrode is arranged to be opposed to each other interposed in the intermediate of the second (first) adjacent subelectrode, and a PTC resistance film 8 is uniformly formed between these first/second subelectrodes. Over a predetermined temperature range, ratio rho(T)/rho(T0) of specific resistance rho(T) at a temperature T of the first/second main electrodes to specific resistance rho(T0) at a reference temperature To (for instance 20 deg.C) is set almost equal to ratio R3(T)/R3(T0) of a resistance value R3(T) at the temperature T of the PTC resistance film 8 between the first/second subelectrodes to a resistance value R3(T0) at the reference temperature T0. |
