| 摘要 |
PURPOSE:To exactly select and detect gas which has been prescribed in advance, by predicting a component of gas to be detected, by an element output of every temperature. CONSTITUTION:An output es of a gas detecting element 6 whose electric characteristic is varied in a gas atmospheric is sent to a gas deciding part 9 through a detecting circuit 7 and an A/D converting circuit 8. A heater 10 for heating the detecting element 6 is controlled by a temperature control part 11. The temperature control part 11 compares a temperature setting signal by a temperature switching part 12, with a signal of a temperature sensor 13 for measuring a temperature of the element 6, and controls the heater 10 so that a temperature of the temperature sensor 13 maintains a temperature set value. By the temperature switching part 12, a temperature of the element is switched to T1, T2 and T3, outputs e1, e2 and e3 at each temperature are measured, an inclination of a characteristic and a curvature are calculated by deriving variation rates DELTAe1, DELTAe2 by the deciding part 9, and whether the output es of the element 6 is an output generated by gas to be detected or not is decided. When said output es is the output of gas to be detected, density of gas is calculated by an absolute value of the outputs e1, e2 and e3.
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