| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas detector for detecting troubles in the semiconductor type gas sensor and another constituent element in the gas detector that have been difficult to detect heretofore for discriminating the content of the trouble. SOLUTION: A first detection resistor R1 and a second detection resistor R2, which are respectively different resistance values between a plate power supply Vcc and a plate electrode 3b, are changed-over and connected by a detection resistor change-over means 12, during the supply of predetermined heater voltage from a heater power supply 11. Furthermore, the difference between the sensor output voltage of the semiconductor-type gas sensor 3, when the first detection resistor R1 is connected to the plate electrode 3b and the sensor output voltage of the semiconductor-type sensor 3, when the second detection resistor R2 is connected to the plate electrode 3b is measured by a sensor output difference measuring means 10b. It is determined that there is trouble on the semiconductor type gas sensor 3 by a first trouble-determining means 10d, when the difference, measured by the sensor output difference measuring means 10b, does not lie within a preset normal range. COPYRIGHT: (C)2007,JPO&INPIT
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