| 摘要 |
PURPOSE:To measure the absolute humidity by using a solid electrolyte consisting of a perovskite type oxide having conductivity to both of a hydrogen ion and oxygen ion. CONSTITUTION:Porous platinum electrodes 2, 3 are provided on both faces of the solid electrolyte 1 consisting of the perovskite type oxide having the hydrogen ion conductivity and the oxygen ion conductivity in combination. One of the electrodes is used as an anode 2 and the other as a cathode 3 and a cap 5 is joined to the electrolyte 1 so as to cover the cathode 3. The oxygen ion and hydrogen ion migrate in opposite directions but electric charges are reverse in positive and negative and, therefore, the currents with the oxygen ion and hydrogen ion as the carriers flow in the same direction when a DC voltage is impressed between the anode 2 and the cathode 3 in a gas to be measured. However, the gas diffusion of oxygen is limited by a microhole 4 of the cathode 3 and, therefore, the oxygen ion decreases to a negligible level as compared to the hydrogen ion and the output current is only the current with the hydrogen ion as the carrier. Since the limiting current of this time has a proportional relation with the absolute humidity, the absolute humidity is known by measuring the limiting current. |
