| 摘要 |
A thermal-type flow sensor of high detection sensitivity and reliability in which a temperature measuring resistor is maintained at a predetermined temperature includes a plate-like substrate (1), a low heat capacity portion (13A) formed on a surface of the substrate (1), a heat generating resistor pattern (4) and a temperature measuring resistor (14) disposed on the low heat capacity portion (13A) and each formed of a heat-sensitive resistance film, and a control circuit (50) for applying a constant voltage (Vcc) to the temperature measuring resistor (14) while supplying a heating current (i) to the heat generating resistor pattern (4) for thereby outputting a flow-rate measurement signal derived on the basis of the heating current (i). The heat generating resistor pattern (4) and the temperature measuring resistor (14) are disposed essentially on a planar array along a direction in which a fluid destined for measurement flows. The temperature measuring resistor (14) is disposed internally of the heat generating resistor pattern (4) at a location upstream of a peak position of a temperature distribution making appearance in the flow direction of the fluid under the action of heat generated by the heat generating resistor pattern (4).
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