| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a NOx measuring device capable of shortening the time until the device becomes stable. <P>SOLUTION: The device is equipped with a NOx sensor element. The NOx sensor element has a solid electrolyte element of oxygen ion conductivity, a flow path to which specimen gas is introduced, a partial pressure of oxygen sensing cell for detecting the partial pressure of oxygen of the specimen gas introduced into the flow path, a first oxygen pump cell for controlling the partial pressure of oxygen contained in the gas that has been introduced, and a nitrogen oxide detecting cell for decomposing nitrogen oxide contained in the gas in which the partial pressure of oxygen has been controlled and detecting the dissociated oxygen. The device has a nitrogen oxide detecting cell, an operational amplifier 22b for creating voltage that is applied to the nitrogen oxide detecting cell, and a diode 22d that is arranged between the operational amplifier 22b and the nitrogen oxide detecting cell and connected between an output-terminal and a reversal input_terminal of the operational amplifier 22b, and that limits the voltage applied to the nitrogen oxide detecting cell to the predetermined voltage that is larger than the predetermined voltage applied when the nitrogen oxide is measured. <P>COPYRIGHT: (C)2004,JPO |
