Piezoresistive pressure sensors are based on the piezoresistive effect, which refers to the phenomenon that the resistance of a semiconductor changes when it is subjected to external force. Piezoresistive pressure sensors are usually made of four equal-value resistor strain elements on a silicon chip, forming a Wheatstone bridge. The silicon chip is the "heart" of the pressure sensor. When subjected to pressure, the resistance of the circuit on the chip changes accordingly. The resistance of one pair of arms becomes more significant, while the resistance of the other becomes smaller. When the bridge is out of balance, it will output a voltage proportional to the pressure. The pressure sensor converts pressure into an electrical signal output when working.

Simply put, the working principle of the piezoresistive pressure sensor is based on the change in the resistance value of the sensing element caused by pressure. The measuring circuit converts the varying voltage signal into an output signal proportional to the pressure.

Piezoresistive Pressure Sensors VS. Piezoelectric Pressure Sensors

Piezoresistive and piezoelectric pressure sensors are two commonly used types of sensors for measuring pressure. The differences are as follows: