The figure is zero and span adjustment circuit includes a feedback resistor network and differential pressure sensing
bridge measuring circuit. Constant current source IO represents the output current. Four bridge arm resistance is R1S, R3S, R4S and R6S. When the positive pressure measured increases, R1S and R6S resistance decreases, R3S and R4S resistance increases, the output signal of the bridge VBr negative increase. This VBr signal corresponding to the voltage deviation in the measured pressure change. After measuring circuit the negative feedback resistor network effect, VB r signal will remain very close to zero.