O2 sensor is an electronic device that is used to gauge the amount of oxygen level in the gas exhausted by an engine. The innovation of this technology was established back in the year 1960. Since the launch of this technology all leading car and other vehicle manufacturers started to use this technology. Over the time, this technology begins to use in the regular vehicles sold to the regular people. This technology help the performance of the engine tremendous way. This sensor is mounted on exhaust system of the vehicle in order to gauge the amount of oxygen mixed with the other gases of exhaust. If it founds that the amount of oxygen is too high, then it send the signal to respective units of the engine so that the ratio of air-fuel can be corrected immediately. It works continuously unless and until the ratio of air-fuel is corrected by respective units of engine that is also known as closed-loop process. Basically, what this sensor does is it converts the signal into electrical. Now you would be thinking how air reading is converted into electrical signals. This sensor uses the platinum coated body of ceramic zirconia. With the unique properties of this technology, it can used be in many other applications apart from vehicle exhaust system such as medical application, scuba diving, etc.