| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an air-flow-rate measuring device in high accuracy, wherein the effect of the fluctuation of a reference voltage signal is avoided. SOLUTION: In a signal correcting means 14 of an air-flow-rate measuring device 1, the detected signal from a detecting means 12 outputted in accordance with the flow rate of air by detecting a current required for heating a heating resistor 11 arranged in an air flow path to the specified temperature is compared with the reference waveform signal generated in a reference-waveform generating means 140 in a pulse-signal generating means 142 in a comparing means 141. The pulse signal having duty, which is changed in accordance with the detected signal, is generated. In a crest-value converting means 143, the pulse signal is converted into the pulse voltage signal, which has the pulse length in accordance with the above described pulse signal and the crest value that is changed in accordance with the reference voltage signal inputted from an external reference-voltage generating means. The pulse voltage signal is averaged, and the corrected detection signal is outputted from a smoothing means 144.</p> |
