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actuator

AK-choo-ay-ter /ˈæk.tʃu.eɪ.tər/

nounC2GREGMAT

technicalengineering

A mechanical device for moving or controlling a mechanism or system by converting energy (such as electricity, air, or hydraulic fluid) into physical motion.

Refers specifically to the 'muscle' of a machine. It takes a control signal and physical energy to produce a mechanical force, distinguishing it from the controller (the brain) and the sensor (the eyes).

The story behind the word. Traces back to the Latin verb agere, meaning 'to do' or 'to drive'. It entered English via the verb actuate (to put into action), eventually evolving in the late 19th century to describe the specific mechanical components that drive machinery.

Word relationships

driver: Driver is a broader term that can refer to software or mechanical components, whereas actuator specifically refers to the physical component producing motion.
motor: A motor is a specific type of actuator that produces continuous rotational motion, while actuators can also produce linear or limited-range movements.

sensor: A sensor detects physical properties and converts them into signals, whereas an actuator does the opposite, converting signals into physical action.

Commonly confused with

transducer: A transducer converts one form of energy to another (which includes both sensors and actuators), while an actuator specifically converts energy into physical motion.

Word family

actuate (verb): To put into action or motion.
actuation (noun): The process of putting something into motion.

Collocations

linear actuator
rotary actuator
hydraulic actuator
piezoelectric actuator

Example sentences

"The engineer replaced the faulty electric actuator to restore precise movement to the robot's elbow joint." A technical manual describing the assembly of a robotic arm.
"Hydraulic actuators are used to adjust the flight control surfaces on commercial aircraft." An article on aerospace engineering.

Memory hook

An actuator is the component that makes a machine 'act' out its commands. Actuator = Action-maker.

When not to use

Do not use to describe purely manual levers or gears that do not convert an energy source into automated movement.

Fun facts

Piezoelectric actuators can move in increments smaller than the width of a single human hair, making them essential for focusing high-powered microscopes.