Which device controls the direction of fluid flow into an actuator?

• A. Selector switch
• B. Absorbs pressure surges
• C. Stores hydraulic fluid
• D. Generates electricity

Answer: (A)

Directing hydraulic fluid to move an actuator requires a device that routes the fluid to the correct side of the actuator. A selector switch serves this role by selecting which path the pressurized fluid takes, sending it to one side to extend and to the other side to retract. In other words, it actively controls which way the actuator moves. The other options perform different functions: absorbing pressure surges helps dampen spikes, storing hydraulic fluid provides volume for the system, and generating electricity is unrelated to directing hydraulic flow. So the selector switch is the component that directly controls the direction of flow into the actuator.