| 摘要 |
<p>PURPOSE:To make it possible to carry out zero adjustment and span adjustment independently by providing an output regulating circuit with a subtractor having one input receiving an output signal from an amplifier and the other input terminal receiving reference voltage. CONSTITUTION:A heating resistor 1 and a temperature-sensitive resistor 2 are set in an air channel 30. A reference resistor 4 for converting the current flowing through the resistor 1 into a voltage and resistors 5, 6, 7 constitute a bridge circuit. The bridge circuit and the resistors 1, 2 control a transistor 3 through differential amplifiers 8, 9 so that the resistor 1 constantly exhibits a predetermined temperature with respect to the air temperature. Consequently, the current flowing through the resistor, and thereby the terminal voltage V0 thereof, varies according to the air flow rate when the temperature of the resistor 1 is controlled at a constant level. An output signal is delivered from a noninverted amplifier 11 to one input terminal of a subtractor 18 in an output regulating circuit 101 having the other input terminal receiving an output from a voltage follower 21 for maintaining a constant reference voltage. Consequently, zero- adjustment can be effected independently of span adjustment.</p> |
