CO _ NOx Sensor

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The CO-NOx Sensor, positioned post a car filter, prevents sickness in drivers by monitoring exhaust gases. It features a diameter of 7mm and height of 20mm. A carbon filter protects the sensitive part from moisture and dust, ensuring better particle separation for selectivity. The sensitive part, electrically wired, is approximately 800µm high with a 6mm diameter. Refer to the diagram for more details. In this sensor, a monocrystalline silicon wafer (500µm), phosphorus oxynitride membrane (3µm), doped polycrystalline silicon heat body (100nm high, 300µm diameter), negligible-height silicon oxide isolation coating, platinum, chromium, and titanium alloy circuits, phosphorus oxide protection coating, and a tin oxide (SnO2) sensing layer (100nm high, 300µm long) are incorporated. The SnO2 sensing layer is heated to 400-600°C by the heat body, facilitating the oxidoreduction reaction (SnO2 + CO = SnO + CO2), which alters electrical conductivity and can be measured in the sensitive layer. Each sensor requires calibration testing for accurate readings.