The working principle of the oxygen sensor is based on the conductivity of oxygen ions. The sensor contains an electrolyte membrane, typically made of stable zirconia material, with different metal electrodes coated on both sides. One side contacts the exhaust gas inside the exhaust pipe, while the other side is exposed to the atmosphere. When the oxygen concentrations on both sides differ, oxygen moves through the electrolyte membrane, generating a potential difference that is directly proportional to the difference in oxygen concentration within the gas. This potential difference is converted into an electrical signal by the internal circuit, reflecting the air-fuel ratio of the mixture. This characteristic of the sensor enables it to serve as a key component in automotive exhaust control systems.