A pressure sensor is a device equipped with a pressure-sensitive element that measures the pressure of a gas or a liquid against a diaphragm made of stainless steel, silicon, etc., and converts the measured value into an electrical signal as an output. Pressure sensors are usually composed of pressure sensitive elements and signal processing units.
The sensors are widely used in various industrial automation environments, hydropower, railway transportation, pipeline and many other industries.According to different test pressure types, pressure sensors can be divided into gauge pressure sensors, differential pressure sensors and absolute pressure sensors.
- What is pressure?
Pressure = Force/Area
In SI (MKS) units, a force of one Newton, applied to an area of one square meter, exerts a pressure of one Newton per square meter, or one Pascal. Any kind of pressure sensor contains a mechanism or structure that reacts proportionately to a force applied. The area over which the force is applied is constant, for a given sensor structure.
- Different sensors are used for different measurement targets, such as liquids, gases, flammable substances, and corrosive substances.
- There are sensors that measure the absolute pressure and those that measure the pressure relative to atmospheric pressure or a specified pressure. For sensors that use atmospheric pressure as a reference, there are sensors that measure negative pressures and positive pressures.
- Operating Principles
- A semiconductor piezo-resistance dispersion pressure sensor has a semiconductor distortion gauge formed on the surface of the diaphragm, and it converts changes in electrical resistance into an electrical signal by means of the piezo-resistance effect that occurs when the diaphragm is distorted due to an external force (pressure).
- A static capacitance pressure sensor has a capacitor that is formed by a static glass electrode and an opposing movable silicon electrode, and it converts changes in static capacitance that occur when the movable electrode is distorted due to an external force (pressure) into an electrical signal.