An oxygen sensor (O2 sensor) is an electronic device that measures the concentration of oxygen (O2) in a gas or liquid. It is used in a variety of applications, including automotive engine management, industrial process control, and medical diagnostics.
Oxygen sensors are typically made of a ceramic material that is coated with a thin layer of platinum or gold. When oxygen comes into contact with the sensor, it reacts with the platinum or gold and creates an electrical signal. The strength of the electrical signal is proportional to the concentration of oxygen in the gas or liquid.