Which device translates electrical signals into mechanical motion to move a surface?

• A. Gyroscope
• B. Servo
• C. Barometer
• D. Altimeter

Answer: (B)

A servo translates electrical signals into precise mechanical motion to move a surface. It contains a small motor and a feedback loop that takes a control signal (often a PWM or similar electrical command) and positions a shaft to a specific angle or distance. This makes it ideal for moving surfaces that require accurate, repeatable positioning, such as control surfaces on a model or a robotic arm. The other devices have different roles: a gyroscope measures angular rate or orientation, a barometer senses atmospheric pressure, and an altimeter measures altitude. They don’t convert electrical commands into controlled motion, which is why the servo is the correct choice.