Hydraulic circuits are comprised of cylinders, valves, pumps, and are connected via hydraulic pipes and tubes. The complexity of these components are difficult to represent fully so hydraulic symbol circuits are used instead. Hydraulic symbols provide a clear representation of each hydraulic component functions. Many hydraulic symbol designs are based industry standards such as DIN24300, ISO1219-1 or -2, ANSI Y32.10 or the ISO5599. While ideally, all hydraulic circuits would use universal symbol notations, one will find differences in hydraulic circuit drawings based on the company and/or vendor. This is due to each one wanting their drawings to stand apart from other drawings found in the industry.
The symbols that represent hydraulic components typically display the following characteristics: function, actuation and return actuation methods, number of connections