Basic Pressure Sensor Design Working Principle

Basic Pressure Sensor Design Working Principle

Industrial pressure sensors also referred to as pressure transducers, pressure transmitters, pressure indicators and pressure switches, normally have a diaphragm type design that uses strain gauges, which are either bonded to or diffused into it, with the strain gauges acting as resistive elements. 

The basic principle of the piezoresistive pressure sensor is to use a strain gauge made from a conductive material that changes its electrical resistance when it is stretched. The strain gauge can be attached to a diaphragm that recognises a change in resistance when the sensor element is deformed. The change in resistance is converted to an output signal

Piezoresistive strain gauge measurements are made using a Wheatstone bridge circuit

Under the pressure-induced strain, the resistive values change. 

In capacitive technology, the pressure diaphragm is a single plate of a capacitor that changes its value under pressure-induced displacement.