What is an actuator?

• A. Provides power and motion to manipulate parts of a valve or damper
• B. Measures temperature
• C. Converts electrical energy to light
• D. Stores hydraulic fluid

Answer: (A)

An actuator is the device that turns energy into physical movement to adjust a control element like a valve or damper. It receives power—electrical, pneumatic, or hydraulic—and converts it into motion that position the valve or damper to regulate flow or airflow.

This fits because the actuator provides the actual motion needed to manipulate parts of a valve or damper in response to a control signal. In contrast, the option that measures temperature is a sensor, which only senses a condition. The option that converts electrical energy to light describes a light source, not movement. The option that stores hydraulic fluid is a reservoir, not a device that moves.