In automotive and construction equipment, the terms hydraulic and pneumatic describe a method of transmitting power from one place to another through the use of a liquid or a gas. Certain physical laws or principles apply to all liquids and gases. You should be familiar with the following terms, as they are associated with hydraulic and pneumatic systems.

HYDRAULICS is a branch of science that deals with the study and use of liquids as related to the mechanical aspects of physics.

PNEUMATICS is a branch of science that deals with the study and use of air and other gases as related to the mechanical aspects of physics.

The chapter covers the basic principles associated with hydraulics and pneumatics, followed by coverage of various system components. The purpose of this information is to give you an analytical understanding of the interrelationships of principles and the components in an operating system.