| 摘要 |
<p>PURPOSE:To enhance the measuring accuracy of the temperature without being adversely influenced by the change of a resistance value due to the temperature change, by providing a dividing circuit which obtains the difference of an output voltage of a differential amplifier circuit and a voltage generated at a resistance connected in series to a temperature sensitive resistance, and outputting the output of the circuit as a measuring signal of the air temperature. CONSTITUTION:A hot wire current detecting resistance R1 is connected in series to a hot wire resistance 1 for measuring the air flow rate. A resistance R7 is connected in series to a temperature sensitive resistance R2. A differential amplifier circuit Z1 controls the heating current of the hot wire 1, which is accompanied with the temperature compensation, when a voltage V2 generated at the resistance R1 and a voltage Vb generated at the resistance R7 are input to the circuit. An output, voltage Va from the circuit Z1 is divided by the voltage Vb generated at the resistance R7 connected in series to the temperature sensitive resistance 2, thereby to obtain the ratio of the Va, Vb. The output, is generated as a measuring signal of the air temperature. Therefore, even when the resistance value of the using resistance is changed the resistance value of the using resistance is changed due to the temperature change, the measuring accuracy of the temperature can be enhanced with being hardly influenced by the change.</p> |
