| 摘要 |
PROBLEM TO BE SOLVED: To accelerate the start of a humidity measuring apparatus using a limit current sensor after turning on power supply. SOLUTION: Voltage are applied to limit current sensors 2A and 2B, wherein the voltage applied to the sensor 2A is set within a range where a first limit current flows proportionally to an oxygen partial pressure, and the voltage applied to the sensor 2B is set within a range where a second limit current flows proportionally to the sum of the oxygen partial pressure and a water vapor partial pressure. By making a power source 3B generate the voltages so as to contain an oscillation component, a current component, which is overshot and attenuated after supplying the voltage to the sensor B, is oscillated. By making the current of the sensor 2B to be obtained through a low-pass filter 6, the current, which does not contain the above current component, can be obtained immediately after voltage impression. |
