| 摘要 |
PROBLEM TO BE SOLVED: To prevent a noise caused by a temperature or humidity change, and erroneous detection caused by drift of a gas sensor signal, to reduce the dispersion of a gas sensor characteristic, and to allow the detection of reduced error. SOLUTION: A gas sensor 1 is connected to a signal electric power source 5 such as a battery via a load resistance circuit. A heater 4 is a heater provided in the gas sensor 1, and the heater 4 is connected to a heater electric power source 3. The power source 3 impresses a prescribed voltage Vh to the heater 4 during its ON-time to heat the gas sensor 1 upto a drive temperature. The power source 3 does not impresses a voltage to the heater 4 during its OFF-time. The ON and OFF of the heater power source 3 are repeated periodically using the operation hereinbefore as one cycle. The load resistance circuit is composed of a resistance 2. The signal electric power source 5 regulates a voltage by a signal electric power source regulating part 6, for example, from an electric power source voltage 5 V to a proper voltage.
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