Zirconia and titania O2 sensors both serve the same purpose of measuring oxygen levels, but they operate using different principles and have different characteristics: Zirconia sensors rely on the Nernst effect, which creates a voltage difference proportional to the logarithm of the oxygen pressure difference across a zirconia cell. Zirconia sensors are excellent at providing accurate and reliable measurements and are commonly used in automobile exhaust systems and industrial applications. Titania sensors, on the other hand, change their electrical resistance according to the concentration of oxygen. When exposed to a rich mixture (more fuel, less oxygen), the resistance of the titania sensor increases; when exposed to a lean mixture (less fuel, more oxygen), the resistance decreases. This type of sensor is simpler and more robust but provides less precise measurements compared to zirconia sensors.