Gas component sensing apparatus

Claim 1

A gas component sensing apparatus comprising: a solid state electrolyte made of metal oxide having an electrical resistance which changes in accordance with a gas component in a gas under test; a holder made of heat resistive, electrically insulative metal oxide and having an axially extending through-hole formed therein, said solid state electrolyte being held at one end of said through-hole; a lead member of conductive material fixed to the other end of said through-hole of said holder; a housing of conductive metal fixed around the outer periphery of said holder; a pair of electrodes formed on opposite surfaces of said solid state electrolyte in such a manner to prevent electrical shortcircuit therebetween; a first electrically conductive path means arranged in said through-hole of said holder for electrically connecting one of said pair of electrodes with said lead member; and a second electrically conductive path means formed in a thin film structure on the outer surface of said holder for electrically connecting the other electrode with said housing; whereby the change in said electrical resistance of said solid state electrolyte is taken across said lead member and said housing.