| 摘要 |
A flow rate sensor detects the flow rate in a pulsating condition including a large amount of the reverse flow. Upstream temperature sensors and downstream temperature sensors are formed in both sides of a heater, parallel resistors are formed in the external side of a thin film portion (cavity), and the downstream temperature sensors are connected at the contacts. The upstream and downstream temperature sensors are respectively allocated to the four sides of the bridge circuit so that the sensors of the same type are not side by side and the electrodes are balanced when the flow rate is zero. The upstream temperature sensor is cooled during the forward flow, while the downstream temperature sensor is influenced by the heater but virtual change is rather small and potential difference between the electrodes becomes larger. During the reverse flow, the downstream temperature sensor is cooled but virtual change is rather small.
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