Which cylinder is characterized by having a single working port and is returned by external forces or by a spring?

Which cylinder is characterized by having a single working port and is returned by external forces or by a spring?

• A. Double-acting cylinder
• B. Single-acting cylinder
• C. Hydraulic Motors
• D. Poppet valves

Answer: (B)

A single-acting cylinder uses pressure on only one side to produce the motion, and the return stroke is accomplished by an external force such as gravity or by a spring inside the cylinder. Because there is only one working port, you apply pressure through that port to extend the piston, and when pressure is removed, the external force or the spring pushes the piston back.

Double-acting cylinders have two ports and can be pressurized on both sides to extend or retract, so they aren’t single-acting. Hydraulic motors are for rotary motion, not linear cylinders, and poppet valves are a type of valve, not a cylinder.