When you’re working with projects involving vacuum pumps, vacuum gauges will show you the pressure in the chamber being evacuated. There are many different approaches to measuring the pressure in a vacuum, but we’ll focus on one of the most common, called the Bourdon pressure gauge.
At the heart of the Bourdon gauge is a C-shaped flattened tube that is connected to the chamber being evacuated. The removal of the air in the tube causes the tube to bend slightly, which moves a mechanism attached to the end of the tube. This mechanism amplifies and converts the bending motion into rotation, moving the pressure dial to indicate the pressure in the tube.