Patent ID: 7288175

Claim:
A gas concentration measuring apparatus comprising: a gas sensor including a cell and a heater, the cell having a solid electrolyte body and working to produce a sensor signal in the form of an electrical change as a function of concentration of a given component of gas, the heater working to heat the solid electrolyte body; and a measurement control circuit designed to perform a heater power supply control function and an averaging function, the heater power supply control function working to control supply of power to the heater to elevate temperature of the solid electrolyte body up to a desired activation temperature thereof, the averaging function working to average the sensor signal outputted from said gas sensor for a given averaging time range so that a first component of the sensor signal to which a noise arising from a change in the power supplied to the heater is added cancels a second component of the sensor signal to which a noise arising from a change in the power supplied to the heater is added and which is reverse in level to the first component to produce an averaged value, said measurement control circuit determining the concentration of the given component of the gas using the averaged value.