| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect an operation temperature of a sensor by measuring an electromotive force between a third electrode and a reference electrode provided on a solid electrolyte. SOLUTION: In this sensor element, a solid electrolyte 1 is provided with a third electrode 7 for detecting temperature air-tightly sealed by a seal 8, while the third electrode 7 is connected to a control circuit 5. When the sensor element is heated with a heating heater 4 in a measurement gas atmosphere to be operated, an electromotive force is generated between a detection electrode 2 and a reference electrode 3. This electromotive force is a gas density measurement potential. An electromotive force is generated between the third electrode 7 and the reference electrode 3 due to a chemical potential difference between alkaline metal ions of both the electrode 7, 3. This electromotive force is a temperature measurement potential. Accordingly, by measuring the electromotive force generated between the reference electrode 3 and the third electrode 7, an operation temperature of the moment can be accurately measured according to a temperature characteristic graph with respect to a potential between the third electrode 7 and the reference electrode 3. By controlling the heating heater 4 or correcting the gas density measurement potential on the basis of the measured operation temperature, an accurate gas density can be displayed on a display part 6. |
