| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a gas concentration detector which enhances the detection precision of the current flowing to a gas sensor element. <P>SOLUTION: The gas concentration detector 1 has a pump cell, a sensor cell 2B and a monitor cell. Constant-current means E1-E3 for allowing a current of a predetermined value to flow to ground potential are respectively provided to the output terminal of a sensor cell differential amplifying operational amplifier OP3 for detecting the potential difference between both terminals of the sensor current detecting resistor Rs provided to the measuring target gas side electrode 203 of the sensor cell 2B, the output terminal of a monitor cell differential amplifying operational amplifier OP4 for detecting the potential difference between both terminals of a monitor current detecting resistor Rm provided to the measuring target 205 of the monitor cell and the output terminal of an NOx concentration detecting operational amplifier OP5 for outputting a voltage based on the NOx concentration performing the differential amplification of the output voltage of the monitor cell differential amplifying operational amplifier OP4 and the output voltage of the sensor cell differential amplifying operational amplifier OP3. <P>COPYRIGHT: (C)2009,JPO&INPIT |
