PURPOSE: To active the characteristic of an oxygen sensor and to enable measurement for a long period of time by impressing an overvoltage to both electrodes of an oxygen ion conductive plate.
CONSTITUTION: An oxygen sensor 1 is installed in a gas G to be measured and is heated to a required temp. A voltage A is then impressed via electrodes 3a, 3b on both surfaces of the oxygen ion conductive plate 2 of the sensor 1 to release the oxygen ion in an isolated space C via the plate 2 to the outside. The impressed voltage is thereafter increased and the resultant limiting current is measured, by which the oxygen concn. in the gas G is measured. An overvoltage is then impressed to the plate 2 and both electrodes 3a, 3b to activate the sensor 1. The overvoltage is impressed in this stage by passing the current exceeding the limiting current to the plate 2 for prescribed time, by which the characteristic of the sensor 1 is reactivated and the measurement is made possible again.
ISHIBASHI ATSUNARI
ASADA AKIYOSHI
ISONO YOSHIYA
