| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an air flow measuring device which compensates response delay of a heating resistor regardless of flow velocity of air to be measured and which has good responsiveness. SOLUTION: A Wheatstone bridge circuit formed with a heating resistor 11, a temperature compensating resistor 12 and resistors 13, 14 is constituted to be adjusted by a differential amplifier 15 and a transistor 16 so that electric potential difference between a point A (connecting point between the resistor 11 and the resistor 13) and a point B (connecting point between the resistor 12 and the resistor 14) becomes zero. With this constitution, temperature difference between the heating resistor 11 and the temperature compensating resistor 12 is kept in constant. At this time, a signal corresponding to velocity of air flow is a current flowing in the heating resistor 11 and it is obtained from electric potential of the point A. Since change of current flowing in the heating resistor 11 has response delay to change of the velocity of air flow, a response compensating circuit 2 for compensating the response delay is connected to the point A, that is the connecting point between the resistor 11 and the resistor 13.</p> |
