Oxygen sensor
（重定向自Lambda probe）
![A three-wire oxygen sensor suitable for use in a Volvo 240 or similar vehicle](/Images/godic/202501/23/Lambda_sond_till_volvo240_etc2045.jpg")
![A planar zirconia sensor (schematic picture)](/Images/godic/202501/23/ZirconiaSensor.svg2045.png")
![A planar wideband zirconia sensor (schematic picture)](/Images/godic/202501/23/WidebandZirconiaSensor.svg2045.png")
![A diving breathing gas oxygen analyser](/Images/godic/202501/23/Diving_oxygen_analyser2045.JPG")
An oxygen sensor (or lambda sensor) is an electronic device that measures the proportion of oxygen (O2) in the gas or liquid being analysed.
It was developed by the Robert Bosch GmbH company during the late 1960s under the supervision of Dr. Günter Bauman. The original sensing element is made with a thimble-shaped zirconia ceramic coated on both the exhaust and reference sides with a thin layer of platinum and comes in both heated and unheated forms. The planar-style sensor entered the market in 1990, and significantly reduced the mass of the ceramic sensing element as well as incorporating the heater within the ceramic structure. This resulted in a sensor that started sooner and responded faster.