| 摘要 |
PURPOSE:To ensure a quick adaptation to a fluctuation of the exothermic temperature, by controlling a power source for electric conduction based on the exothermic temperature of a resistance heating element and a change of resistance value to the exothermic temperature. CONSTITUTION:When a switch (SW)15 is first turned on, a transistor (TR)16 is turned on. As a result, a semiconductor SW12 is also turned on, and accordingly a resistance heating element 13 generates the heat with the current supplied from a power supply terminal 11. If a certain voltage is applied to the terminal 11, the terminal voltage of a resistance 14 is reduced as the resistance value of the element 13 increases. This terminal voltage is compared 18 with the reference voltage, and the output potential of the comparator 18 is reduced when the difference between the exothermic temperature and the target value becomes a prescribed level due to the fact that the exothermic temperature of the element 13 exceeds the target level. As a result, the TR16 is turned off and accordingly the SW12 is also turned off to stop the electric conduction to the element 13. |
