| 摘要 |
PURPOSE:To manufacture an apparatus at a low cost, to improve reliability and to improve the temperature rising characteristic of control characteristics and the recovering characteristic at the time of momentary power failure. CONSTITUTION:A gas detecting element has a gas sensor element 2 having a resistor heater 201 with temperature coefficient and a constant-current circuit 1 for holding in control of gentle temperature rising at the start of the gas sensor element 2 and at a preset temperature. In this apparatus, the increasing amount per hour W of power applied on the resistor heater 201 becomes Rh.I<2>. The temperature can be slowly increased in response to the increment of the resistance Rh of the resistor heater 201. At Pt, the changing amount of resistance due to temperature is decreased bit by bit when the temperature rises. Therefore, the increasing amount per hour Rh is decreased as the temperature rises more higher. |
