What is a stain gauge?
The strain gauge of an electrical resistance of a wire is directly related to the length of the wire and inversely related to its cross section. In other words, the longer the wire or the shorter the cross section, the higher the electrical resistance of the wire. Strain gauges are one of the most common pressure transducers.
This strain gauge includes a diaphragm sensor with one or more electrical resistors attached to it. These resistors are usually mounted on a separate screen and their assembly is located on the diaphragm. The tension of the sensor due to the application of pressure causes the plate to stretch by a few microns, and because the electrical resistor is completely attached to the plate, changing the length of the plate changes the length of the resistor and consequently changes its electrical resistance.
This change in electrical resistance, which is proportional to the amount of pressure applied, is measured by a Watson bridge, and finally the amount of pressure change is calculated and sent to the display or control system.