What is the primary difference between single-acting and double-acting cylinders?

The primary difference between single-acting and double-acting cylinders lies in their operational mechanics. Single-acting cylinders use air pressure to perform work in one direction only, typically either extending or retracting. They rely on a spring or some other mechanical means to return to their original position after the pressure is released. This means that the force generated is only effective as long as air pressure is applied in one direction.

In contrast, double-acting cylinders utilize air pressure for both the extension and retraction functions. They have two chambers: one for applying pressure to extend the cylinder and another for retracting it back to its original position. This design allows for greater control and force application in both directions, making double-acting cylinders more versatile in applications requiring more complex movement.

Other choices may include comparisons of efficiency, capability, or pressure ratings, but these do not accurately capture the fundamental operational differences and functionalities of single-acting and double-acting cylinders. Thus, the correct answer effectively highlights the essential functional disparity between the two types of cylinders in pneumatic systems.