On a daily basis, billions of pressure sensors are used for monitoring pressures of fluids in engines, hydraulics and pipes. Specialised sensors are also used for determining the pressures of gases. A typical pressure sensor is generally about a cubic inch in size. However, some sensors may be a hundred times or more smaller – for example the ones used in microelectromechanical systems.
Most modern pressure sensors work on the principle known as piezoresistance. Pressure causes a substance to conduct electricity at a particular rate, thus leading to a specific charge flow related with a certain level of pressure. This charge is generally fed to a wire that leads to the display and control panel for human analysis.
Traditional pressure sensors utilise strain gauges, resistors, polycrystalline semiconductors, or metal alloys as the resistive media. These materials conduct electricity depending on the geometric deformations in their structure. As a linear rise in pressure does not cause a linear magnitude in deformation, the calibration technique should be used for determining the actual pressure. They are generally in-built in the majority of systems.
Many different types of pressure sensors are now available for different uses. One is a complete pressure sensor that measures the total pressure using a vacuum as a point of reference. Another is a gauge sensor. It generally measures the pressure with reference to the ambient atmospheric pressure. Moreover, there are different types of pressure sensors that are specially used for measuring the difference between two contacts.
