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thumb|right|Electro-galvanic fuel cell as used in a diving [[rebreather to measure the partial pressure of oxygen. ]]
thumb|Two oxygen cells as used by oxygen analysers for diving gas showing commonly used connectors
An electro-galvanic fuel cell is an electrochemical device which consumes a fuel to produce an electrical output by a chemical reaction. One form of electro-galvanic fuel cell based on the oxidation of lead is commonly used to measure the concentration of oxygen gas in underwater diving and medical breathing gases.
Electronically monitored or controlled diving rebreather systems,