Abstract: Air conducting connector with simplified wiring layout and water-proofing. Connector 2 has air conduction path 3, having a first opening 3a and a second opening 3b. A heater wire 5, air conducting wire and terminal 6 of ECU side are inserted into the first opening 3a, while an air-conducting heater wire 7 and terminal 8 of sensor side are inserted into second opening 3b. Within the air conduction path 3, the ECU side terminal 6 and the sensor side terminal 8 are electrically interconnected. First opening 3a is sealed with resin. The rear part of the air conduction path 3 is sealed with a sealing material 8b. The sensor side terminal 8 and the ECU side terminal 6 are electrically interconnected on insertion to communicate an air conducting part of the sensor side heater wire 7 with an air conducting part of the ECU side heater wire 5 through air conduction path 3.

Abstract: NOx sensor element of oxygen-ion conductive solid electrolyte body 15; flow passage (7, 5, 8, 6) provided within the body for introducing analyte gas; oxygen partial pressure detection cell 3; first oxygen pump cell 1 for controling oxygen partial pressure of the gas in the flow passage; and nitrogen oxides detection cell 2 for decomposing nitrogen oxides in the gas having a controlled oxygen partial pressure and for causing dissociated oxygen to migrate through the solid electrolyte body (see FIG. 1). Operational amplifier 22b is connected between the nitrogen oxides detection cell 2 and a 12 V battery power source to generate a voltage applied across the nitrogen oxides detection cell 2; and diode 22d connected to a point between the operational amplifier 22b and the nitrogen oxides detection cell. The diode clamps the voltage to an activation voltage higher than the measurement voltage during activation.