Temperature compensation in mass flow sensors after the principle of a hot wire anemometer

摘要

The circuit includes a bridge circuit with an air flow measurement resistance (RL) exposed to the air flow and connected in one bridge arm in series with a current measurement resistor (R1). A temp. compensation resistor (RT) detecting the air temp. is connected in the other bridge arm in series with a fixed resistance (R2). The bridge difference voltage in the bridge diagonal is detected and used to balance the bridge. The measurement voltage resulting from the sum of the voltage across the current measurement resistor and a partial voltage across the air flow measurement resistor is evaluated as a measure of the air flow.