Zirconia Sensor
An important property of the zirconia element is that it can contuct oxygen ions above a temperature of about 350℃. When the sensor is fitted, the outside of the zirconia element is exposed to the exhaust gas and the inside is in connected with air. Both sides of the element are coated with a thin layer of platinum that act as electrodes and cary the sendors signal(volatge) from the zirconia element to the lead wire. At operating temperature, oxygen ions are able to pass through the element and deposit a charge on the platinum electrode thus generating the voltage signal.