Patent ID: 7309848

Claim:
A gas sensor comprising: a cup-shaped sensor element working to produce a signal as a function of a concentration of gas to be measured; a housing within which said sensor element is retained; a gas cover joined to said housing to define a gas chamber into which the gas is admitted and to which said sensor element is exposed; an air cover joined to said housing to define an air chamber into which air is admitted through a water-repellent filter as a reference gas and which leads inside said sensor element; and a ceramic heater disposed inside said sensor element, said ceramic heater including: a ceramic body; a pair of electrical conductors formed on said ceramic body, each of said conductors is equipped with a terminal; leads joined to the terminals of said conductors for supplying electrical power to said conductors; and a seal covering joints between said leads and the terminals of said conductors hermetically, said seal being disposed inside the air chamber.