| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve the accuracy in measurement of a low flow rate area, by using a correction circuit comprising the second resistor which receives the thermal influence of a base, on an equality with the first temperature-sensitive resistor, and corrects and outputs an air flow rate signal. SOLUTION: In a driving circuit 5, a heating resistor RH measures the intake air flow, and the first temperature-sensitive resistor RC compensates the intake air temperature. The heating current Ih is flown to the resistor RH so that the constant temperature is kept between them, and an air flow signal V2 is output. On the other hand, in a correction circuit 6, the second temperature-sensitive resistor RC2 for compensating the special temperature, and a temperature-sensitive resistor RC3 for partial pressure are connected in series, and the resistor RC2 is connected with an output side outputting the air flow signal V2 , of the driving circuit 5. Further the resistor RC3 is connected with - side (minus side) of the driving circuit 5. On this occasion, the resistor RC2 is installed in an air path same as that of the resistor RC, and is supported by a base, so that it receives the thermal influence from the base on an equality with the resistor RC. And the air flow signal V2 is corrected by partial pressure, and an output signal V0 is output. Thereby the accuracy in measurement, in the low flow rate area, can be improved.</p> |
