Pressure can be expressed in several units, with the most common being pascals (Pa) in the International System of Units (SI), pounds per square inch (psi) in the imperial system, and bar or atmospheres (atm) in other contexts. Absolute pressure measures total pressure relative to a perfect vacuum, while gauge pressure compares pressure to atmospheric pressure. Differential pressure indicates the difference between two pressures, often used in flow measurement and filtration systems.
Measuring pressure typically involves sensors or transducers that convert physical pressure into an electrical signal. Common types include strain gauge-based sensors, piezoelectric transducers, and capacitive or piezoelectric pressure sensors. These devices are designed for various ranges, from low-pressure applications like blood pressure monitoring to high-pressure environments such as hydraulic systems or deep-sea exploration.
Calibration and accuracy are critical in pressure measurement to ensure reliability. Instruments must be regularly calibrated against known standards to account for drift, environmental factors, and wear. Digital pressure gauges and electronic transducers often incorporate built-in calibration features and data logging capabilities for improved precision.
In addition to direct measurement, indirect methods such as manometers (using fluid columns) and bellows-based gauges are used in specific applications. Modern advancements have introduced smart sensors with wireless connectivity, enabling remote monitoring and integration with industrial control systems (ICS) for automation and predictive maintenance.