The selection of hydraulic components for use in a given application is determined by their ability to meet the required specification within the desired cost framework. A variety of components can be arranged to fulfil a given function by using different circuit configurations as the fluid power system designer has the freedom, within the constraints set by the preferences of the machine builder and /or the user, to select components of his choice.

This freedom makes it difficult to summarise circuit design however, the designer needs to be able to justify the circuit on the basis of technical considera­tions. This chapter therefore describes and, where applicable, evaluates a variety of circuit options that can be used for the range of functions generally encoun­tered in the application of fluid power systems.