Pneumatic systems function by using the power of a compressed gas to move components in circular or linear paths. The most essential pneumatic component is the pneumatic cylinder, which uses compressed gas to produce reciprocating linear motion.
Pneumatics are similar to hydraulics in that they both use a fluid to move a component in a desired direction. The difference between pneumatics and hydraulics is that the former uses a compressible gas, such as air, whereas the latter uses an incompressible liquid, such as oil. Although there are losses in power transfer associated with pneumatics that are not present in hydraulics, pneumatics may still be the system of choice because of their quietness, cleanliness and compactness.
Hydraulic systems require large reservoirs to store the hydraulic fluid, whereas pneumatic systems can suck in and compress air on demand. Pneumatic systems do not run the risk of leaking fluid and contaminating their surroundings, making them ideal for ultra-clean environments such as clean rooms and semiconductor fabrication facilities. The compressibility of the gas used depends on environmental parameters such as atmospheric pressure and temperature, affecting the precision of the pneumatic cylinder. This makes pneumatics unfavorable for control applications requiring precise control over component movement.