| 摘要 |
PURPOSE:To stabilize the temperature of a sensor even when the temperature of a gas to be measured changes significantly by controlling an applied voltage to a heater so as to keep the applied voltage to the heater constant in a low gas temperature range and the resistance of the heater constant in a high gas temperature range. CONSTITUTION:A heater applied voltage adjusting means 4 adjusts an applied voltage to a heater 3. When a gas temperature range judging means 7 determines whether a detection value of a heater current is above a specified value or not, a heater applied voltage control means 8 determines a control value so that the heater applied voltage is kept constant when the heater current is above the specified value or so that a heater resistance is determined from detection values of a current of the heater and the applied voltage to the heater to keep the resistance of the heater constant when the heater current is below the specified value. The results are outputted to the heater applied voltage adjusting means 4. |
