| 摘要 |
In order to provide a thermal mass flowmeter which makes higher accuracy of gas flowrate measurement possible while reliability in the thermal mass flowmeter is ensured (while deterioration or breakage caused by droplet adhesion is prevented), the thermal mass flowmeter according to the present invention has a heating element for generating heat by conduction, a temperature detection bridge circuit for detecting a temperature of the heating element, and a sensor element driving circuit portion connected to the heating element and the temperature detection bridge circuit and executing conduction control to the heating element, in which the sensor element driving circuit portion has an output mechanism and an output impedance adjustment mechanism and the output impedance adjustment mechanism is disposed between the output mechanism and the heating element and its output impedance is higher than an electric resistance value of the heating element and less than 1 M©. |
