By measuring the output electromotive force E of the oxygen probe and the thermodynamic temperature T of the gas being measured, the oxygen partial pressure (concentration) PO2 of the gas can be calculated. In practical applications, after detecting the oxygen electromotive force and temperature of the gas, a mathematical model can be constructed based on the Nernst equation, allowing for the accurate calculation of the oxygen content (percentage) of the gas being measured. This is the core detection principle of zirconia oxygen probes.