Parkhurst & Wendel, L.L.P.
Gas sensor
 Disclosed is a gas sensor comprising a main pumping cell for pumping-processing oxygen contained in a measurement gas introduced into a first chamber, an auxiliary pumping cell for pumping-processing oxygen contained in the measurement gas introduced into a second chamber, a measuring pumping cell for pumping-processing oxygen in the measurement gas introduced via a third diffusion rate-determining section, an ammeter for detecting a pumping current generated depending on an amount of oxygen pumping-processed by the measuring pumping cell, a heater for heating at least the main pumping cell, the auxiliary pumping cell, and the measuring pumping cell to a predetermined temperature, an impedance-detecting circuit for detecting an impedance between an inner pumping electrode and an auxiliary pumping electrode, and a heater control circuit for controlling electric power application to the heater on the basis of a value of the impedance detected by the impedance-detecting circuit. Accordingly, it is possible to realize suppression of variation in detection output which would be otherwise caused depending on the measurement gas temperature and a high S/N ratio of detection output. 
NGK Insulators, Ltd.
G
G01N
inventional
Yasuhiko Nobuhide
Hamada Kato