| 摘要 |
PURPOSE:To enable measurement of the composition of exhaust gas on the side of a lead without being influenced by the temperature of the exhaust gas, by providing gas-sensitive parts formed of metal-oxide semiconductor material on both front and back surfaces of the same base plate and by making one gas- sensitive part serve as a temperature compensating part contacting with the air. CONSTITUTION:On both surfaces of a refractory ceramic base plate 1 such as alumina are formed electrode layers 4, 5, 6 and 7 formed of Pt or the like and the gas-sensitive layers 2 and 3 formed of the metal-oxide semiconductor material. The element part thus formed is housed in a metal housing 11 and sealed from the exhaust gas by a metal packing 13 and electrode leads are fixed thereto by a ceramic insulator 12. The gas-sensitive layer 2 contacts with the exhaust gas, while the gas-sensitive layer 3 contacts with the air through the center hole of the ceramic insulator 12. Since the concentration of oxygen in the air is fixed, no change in the resistance of the gas-sensitive layer 3 is caused by the density of oxygen, while its resistance is changed by the temperature of the exhaust gas since it is formed on the same base plate with the gas-sensitive layer 2. |
