What common characteristic do both hydraulic and pneumatic systems share?

Both hydraulic and pneumatic systems are designed to convert fluid power back to mechanical power, which is a fundamental aspect of their operation. In hydraulic systems, this conversion involves the use of liquid, typically oil, which transmits force through pressure. In pneumatic systems, compressed air or gas is used to achieve similar results, with the conversion happening when the fluid expands and pushes against mechanical components, such as pistons.

The principle of converting fluid power to perform work is crucial for both systems and allows them to operate various tools and machinery effectively. This functionality underlies many applications in industrial, automotive, and aerospace fields, where both hydraulic and pneumatic systems are prevalent.

While hydraulic systems use incompressible liquids and pneumatic systems utilize compressible gases, the core feature of both systems is their ability to harness fluid power for mechanical applications, which is not dependent on the compressibility of the working fluids or pressure control mechanisms.