Gas sensor

摘要

A gas sensor which can be used for measuring a low concentration repeatedly, which has a quick response and which can be used for a long time with high stability is provided. The gas sensor comprises a solid electrolyte, a detecting electrode provided in contact with one of the surfaces of the solid electrolyte and exposed to a gas to be detected, a counter electrode, provided in contact with the other surface of the solid electrolyte, and lead wires to place an electric voltage across both electrodes or to take out electric signals, wherein an inactive substance which is hard to form a reaction product with the gas to be detected is used as a material to constitute both electrodes.