| 摘要 |
<p>PURPOSE:To increase the measuring accuracy and response, by using the output signal of the first and second temperature dependancy resistors respectively provided at the location not subjected to thermal effect of the heater in the measuring tube and at the down stream of the electric heater in the flow rate measuring tube, for the measurement. CONSTITUTION:The bridge circuit is formed with the first temperature dependancy resistor 11 placed at the down stream of the electric heater 10 located in the flow rate measuring tube 9, second temperature dependancy resistor 12 placed at the location not subjected to thermal effect from the electric heater, and two reference resistors 16. Further, by applying voltage to the electric heater 10 and the bridge circuit, the voltage control circuit 17 is constituted so that the potential difference at the diagonal points of the bridge circuit can be controlled to a given value in unbalanced condition. Since the flow rate of measured gas is proportional to the third power of the voltage or current fed to the electric heater, the measuring accuracy and response can be increased.</p> |
