Pressure gauge, 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 centimeter.

The tip of the sensor has a spring that is attached to a rod, leading up to the gauge needle. The spring sits inside the stems sensing end. When heat is applied to the sensing coil, movement in the coil is created which causes the needle in the gauge to move – thus displaying the temperature.