| 摘要 |
<p>PURPOSE:To absorb the variance of a flow sensor device by correcting the output signal of a flow velocity sensor driving circuit with flow velocities at two points. CONSTITUTION:A resistance bulb 16 is put in a flow of fluid. Then resistance bulbs 15 and 16 have a difference in resistance value and then two input voltages to a differential amplifier 17 becomes different. A current flowing through a resistance 18 for heat generation becomes a current corresponding to the difference (flow velocity of fluid) between the two input voltages. This current makes the resistance 18 to generate heat, which overheats the resistance bulb 16 up to the same resistance value with the resistance bulb 15, so that the flow velocity sensor driving circuit enters a balanced state. The current applied voltage V to the resistance 18 is led out and used to measure the flow velocity. This voltage V is inputted to the differential amplifier 5 of the flow velocity sensor output signal correcting circuit. Then one of two flow velocity sensor driving circuits of the same constitution is used as a reference circuit and the other is to be corrected, thereby correcting the output of the circuit to be corrected according to the output of the reference circuit.</p> |
