| 摘要 |
PURPOSE: To accurately linearly measure oxygen concentration in a wide measuring range from low concentration of ppm level to high concentration of percent level by one small-sized direct insertion type oxygen sensor. CONSTITUTION: The oxygen concentration meter comprises a sensor 1 made of solid electrolyte of oxygen ion conductor, a voltage applying unit 2 for applying a voltage to the plate of the sensor 1, a current detector 3 for detecting the critical current flowing to the sensor 1, and an applied voltage switching unit 4 for switching the voltage applied to the sensor 1 by the unit 2 to a low voltage with low oxygen concentration or a high voltage with high oxygen concentration, wherein the plate applying voltage is automatically switched to high or lower in response to the high or low of type oxygen concentration to be measured. |
