| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a flow measuring device using a flow sensor for accurately measuring a flow rate by reducing the influence of common mode noise. SOLUTION: This flow measuring device is provided with a difference detecting means 21 for detecting a difference between the detected output of an upstream temperature sensor 8 and a downstream temperature sensor 5 in the on-state of a heater 4, and an addition means 22 for detecting the sum of detection output of a right side temperature sensor 11 and a left side temperature sensor 13. In this flow measuring device, the flow rate of gas is calculated according to the output 22 of the difference detecting means 21 and the addition means 22. The addition means 22 is formed by a differential amplifier 38, one temperature sensor of the right side temperature sensor and the left side temperature sensor 13 is connected to one input terminal of the differential amplifier 38 to supply detection output having one polarity, and the other temperature sensor is connected to the other input terminal to supply the detection output having a reverse polarity.</p> |
