| 摘要 |
PURPOSE:To correct the initial sensitivity of a gas sensor by setting the sensitivity thereof so as to change proportionally according to a difference in the output voltage thereof between the time for starting and ending a cleaning inside the chamber of an oven. CONSTITUTION:Resistances R1 and R2 are connected in series to a gas sensor 1 through switches S1 and S2. The switches S1 and S2 are controlled with a relay driving circuit or the like depending on the magnitude of a voltage Vdefas difference between the output voltages at the time of starting a cleaning heating inside an oven and at that of ending it. When the voltage Vdef as the difference is below a fixed value, with the switches S1 and S2 turned ON simultaneously, the sensitivity of the gas sensor is minimized. When it is close to the fixed value, with either of the switches S1 or S2 turned ON, the sensitivity thereof is set to an intermediate position. When it is above the fixed value, with the switches S1 and S2 turned OFF simultaneously, the sesitivity thereof is maximized. |
