| 摘要 |
<p>A mass flow controller is disclosed herein having a bridge with a pair of arms positioned in good heat transfer relation with a gas stream, the flow rate of which is to be controlled and energized by a constant current generator wherein a resistance difference due to differential cooling by the gas stream is sensed by a bridge amplifier. A linearization network receives a signal from the bridge amplifier and applies one or more correction factors to the bridge amplifier signal to yield a linearized signal having a substantially linear relation to the rate of flow of the gas stream. A comparator receives the linearized signal and a user selectable set point signal and produces a comparator output signal which is sensed by a servoamplifier. The servoamplifier controls a valve which meters the rate of flow of the gas stream.</p> |
