| 摘要 |
PROBLEM TO BE SOLVED: To provide a heat sensor which can secure constant sensitivity for a temperature rise rate irrespective of an outer temperature. SOLUTION: The heat sensor is provided with a switch circuit 3 which is constituted by connecting an outer heat sensitive resistance element TH1 arranged outside a sensor main body 2 and an inner heat sensitive resistance element TH2 arranged inside in series. which changes over voltage Vin giving a difference between inside/outside temperatures by inner/outer heat sensitive resistance elements TH1 and 2 and voltage Vin giving the outer temperature by the outer heat sensitive resistance element TH1 so that they are alternately measured, a voltage measuring circuit 4 measuring voltage switched by the switch circuit 3, a plurality of comparison circuits 5 (1, 2 and 3) comparing and judging different reference voltages Vref1 and 2 with voltage Vin and emitting an alarm signal and a control circuit 6 controlling the comparison circuit selected in accordance with the outer temperature measured by the voltage measuring circuit from the plurality of comparison circuits 5 (1, 2 and 3) to compare and judge the voltages. COPYRIGHT: (C)2004,JPO
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