| 摘要 |
PROBLEM TO BE SOLVED: To secure a calorific value of exothermic resistance by installing a division point in a temperature detection wire of a heating element by connecting a diode to the installed division point and by making a resistance value of the temperature detection wire smaller in order to solve a problem that the exothermic resistance does not generate calories required to blow out a temperature fuse since a resistance value of the temperature detection wire is large in safety operation when a fuse element melts, concerning a planar heater in which a means of shutting off energizing safely when an energization means to a heater wire becomes out of order. SOLUTION: The temperature detection wire 24 of the heating element 21 is divided, a first diode 34 and a second diode 35 are connected to the division point (a), a resistance value of the temperature detection wire 24 in a safety operation is made smaller when the fuse element 23 is fused, the calorific value of the exothermic resistance 36 is secured, and even in an environment in which a peripheral temperature and an alternate current power supply are reduced, regarding an electric carpet or the like of a large area, the safety operation is made secured when a heater wire 22 and the temperature detection wire 24 are short-circuited. COPYRIGHT: (C)2007,JPO&INPIT
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