A pressure gauge is an instrument for measuring the condition of a fluid (liquid or gas) that is specified by the force that the fluid would exert, when at rest, on a unit area, such as pounds per square inch or newtons per square centimetre
A bourdon tube is the most commonly used pressure gauge. It is a mechanical instrument that measures the pressure without an electric supply. It is usually made of steel to resist wear and corrosion. A bourdon tube pressure gauge can measure pressure from 0.6 to 7000 bar (8 to 10000 psi).
