Which of the following is not shown in a hydraulic schematic?

• A. Liquid
• B. Pump
• C. Actuator
• D. Relief Valve

Answer: (A)

Hydraulic schematics convey how fluid power is controlled, not the liquid itself. They use standard symbols to represent components like pumps, actuators, and relief valves, and lines to show where the fluid flows. The fluid is the working medium and isn’t depicted as a separate object with its own symbol; its presence is implied by the lines and the components connected to them. A pump is shown as the energy source that pressurizes the fluid, an actuator converts that pressure into motion, and a relief valve protects the system from overpressure. Sometimes a reservoir symbol appears to indicate where fluid is stored, but there isn’t a generic symbol for “liquid” as an item. So the liquid isn’t shown as a distinct symbol in a hydraulic schematic.