A basic hydraulic circuit consists of a power supply, pump, reservoir, relief valve and control valve. Common control valves include mechanically or solenoid operated valves, open or closed center valves. Common pumps include gear, piston, vane, and tandem pumps. Additional components are flow control valves, selector valves, flow dividers, check valves, and relief valves. Proper interaction of these components allows for control of hydraulic cylinders, motors, and remote fluid distribution.