The output signals of electric bridge are weak and the work
environment of dynamic torque sensors is complex and
bad. There are a lot of interference signals, such as power
supply, electrostatic and electromagnetic interference etc.
Therefore, the output signals of electric bridge must be
enlarged in order to support follow-up circuit. General
operational amplifiers can not constrain the interference
signals effectively. So it can not be applied on precision
occasions. To ensure the linearity of dynamic torque
sensor, amplifier circuit is requested to have high
common-mode rejection ratio, high gain, low noise and
high input impedance, so it's better to select
instrumentation amplifier to achieve voltage signals
amplification