| 摘要 |
PURPOSE:To compensate an ambient temperature by turning on/off a heater for indirectly heating of an indirectly-heated thermistor at a prescribed time and comparing the detected temperature just before turning-on of this heater and that just before turning-off of this heater with each other. CONSTITUTION:A thermistor 6 constitutes a series circuit together with a resistance R1 and is connected between electric power supply terminals VDD and VREF of a microcomputer 9. A resistance R2 is connected in parallel to the thermistor 6. A terminal D of the computer 9 is connected to the base of a transistor 8 through a resistance R3. The turning-on time of a heater 7 for indirectly heating is determined by a timer in the computer 9, and the turning-off time of the heater 7 is determined by another timer, and the detected temperature just before turning-off of the heater 7 and that just before turning-on of the heater 7 are compared with each other. Thus, the power consumption due to the heater 7 is reduced, and compensation of the ambient temperature is possible. |
