| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas detector provided with a failure detection function capable of accurately detecting failure of a heater for heating control of a gas detecting element, or its peripheral circuit. SOLUTION: The gas detector is provided with the gas detecting element 11, the heater 12 heating the gas detecting element 11, a gas detecting part 22 carrying out gas detection on the basis of a sensor output voltage Vs of the gas detecting element 11, a heating control part 20 carrying out heating control of the heater 12, and a heater failure detecting part 30 detecting failure of the heater 12 or its peripheral circuit. The heating control part 20 carries out heating control of periodically repeating two temperature states. The heater failure detecting part 30 respectively determines throughout a plurality of cycles whether or not voltage differences of the sensor output voltages Vs in the two temperature states of the gas detecting element 11 by the periodic heating control are within a predetermined failure voltage range, and if the determination continues for a predetermined standard number of times or it reaches the standard number of times within a certain period, it is determined that the heater 12 or its peripheral circuit has failed. COPYRIGHT: (C)2006,JPO&NCIPI
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