| 摘要 |
PURPOSE:To accomplish the detection of oxygen concentration in a wide range, by altering the voltage to be applied to an electrode sequentially within the range of applying the threshold current according to the concentration of oxygen. CONSTITUTION:As the concentration of oxygen rises in the atmosphere of a zirconia type sensor 1, current I flowing through an electrode 6 and a lead 8 goes up to raise the voltage V2. With the rise in the voltage V2, the amplified voltage V1 rises. If the increment of the voltage V1 is set larger than the imcrement of the voltage V2, the applied voltage VSO between the electrodes 5 and 6 will also rise as difference between the voltage V1 and V2. As the oxygen concentration decreases in the perimeter of the sensor 1, the voltage V2 drops with the drop in the current I and finally, the voltage V1 comes down at a rate larger than the drop of the voltage V2 thereby lowering the applied voltage VSO. Thus, the voltage VSO is shifted automatically within the range of applying the threshold current thereby enabling the detection of oxygen concentration in a wide range. |
