The ME3-C₂H₄ type electrochemical gas sensor is based on the principle of electrochemistry. It utilizes the electrochemical reaction that occurs on the working electrode of the gas to be measured in an electrolytic cell. The current generated by the gas to be measured during the electrochemical reaction is proportional to its concentration and follows Faraday's law. Therefore, the concentration of the gas to be measured can be determined by measuring the magnitude of the reaction current.