HOT-WIRE FLOW RATE MEASURING APPARATUS

摘要

A hot-wire flow rate measuring apparatus includes a first thermo-sensitive resistive element disposed in the flow path of fluid under measurement, resistor unit connected in series to the first sensing element, a second thermo-sensitive resistive element for temperature compensation disposed in the flow path of the fluid, a control circuit adapted to supply a current to the serial connection of the first sensing element and the resistor unit in response to the difference between the voltage produced by the first sensing element and the voltage produced by the second sensing element, and an output circuit for producing a voltage representative of the fluid flow rate in response to the terminal voltage of the resistor. The apparatus is further provided with a current circuit which controls the output characteristics of the output circuit by supplying a compensation current proportionate to the terminal voltage of the resistor to a portion of the serial connection.