| 摘要 |
PURPOSE:To facilitate the simultaneous measurement of an oxygen concn., the absolute humidity quantity and a combustible gas concn. by forming two pieces each of a pair of electrode films of an oxygen sensor, supplying the voltage above the electrolysis voltage of water to the one electrode film and supplying the voltage below the electrolysis voltage of water to the other. CONSTITUTION:The oxygen in the air is made into oxygen molecules by the transfer and receipt of electrons to and from the electrode 2a for supplying the driving voltage. The oxygen molecules release the electrons in the same electrode film 2b after the passage through a solid electrolyte plate 3 having an oxygen ion conductivity. These electrons flow out again as oxygen. The current exhibits a specified value regardless of the voltage value if the inflow of the oxygen is limited by a spacer 4 for controlling the oxygen diffusion. The oxygen concn. is measured by utilizing the characteristics of the threshold current. On the other hand, the threshold current by the spacer 4 is the current value added with the oxygen concn. and the moisture concn. and, therefore, the moisture concn. is measured by subtracting the current value obtd. from the electrode values 2a, 2b. The combustible gas comes into contact with a gas sensitive film 7 of a metal oxide semiconductor type. A change in the electric conductivity is detected by electrodes 6a, 6b for detecting the electric conductivity. The measurement of the concn. is thus executed. |
