초록 ▼

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

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 ouptut 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.

대표청구항 ▼

A hot-wire flow rate measuring apparatus comprising: a first thermo-sensitive resistive element disposed in the flow path of fluid under measurement; first resistor means connected in series with said first thermo-sensitive resistive element to form a first series circuit; a second thermo-sensitive

A hot-wire flow rate measuring apparatus comprising: a first thermo-sensitive resistive element disposed in the flow path of fluid under measurement; first resistor means connected in series with said first thermo-sensitive resistive element to form a first series circuit; a second thermo-sensitive resistive element for temperature compensation disposed in the flow path of the fluid; second resistor means connected in series with said second thermo-sensitive resistive element to form a second series circuit; means for detecting the difference between a voltage corresponding to a voltage across said first thermo-sensitive resistive element and a voltage produced by said second thermo-sensitive resistive element; means for controlling a current fed to said first series circuit in accordance with the voltage detected by said detecting means; an output circuit for outputting a voltage indicating a flow rate of the fluid in accordance with the voltage across said first resistor means; a current circuit including means for supplying a compensation current, which is controlled by a voltage across said first resistor means, to a part of said first series circuit, whereby variations of the output characteristics of said output circuit caused by the variations of the characteristics of said thermo-sensitive resistive elements can be compensated in accordance with said compensation current.