What's An Actuator: Definitions and Components

by Ajay Arora

What's an actuator?! Don't worry. We've got you covered.

A linear actuator is a device that turns rotary motion into linear motion, but if you're new to automation, this explanation might just create more questions than it does answers. Let's start off with a dictionary definition.

Linear: adj., extended or arranged in a line.

Any motion that moves in a straight line is considered linear motion

Actuatorn., 1. a person or thing that actuates., 2. A servomechanism supplying and transmitting energy for operation in another mechanism.

Actuateverb., to put into action; begin a process; to turn on.

By these definitions, it's a device that moves in a straight line in order to affect change in another system. There are many different types, but for this article, we will be focusing primarily on lead screw technology.


what's an actuator grape press

Linear motion has been used as a tool for a long time. Some of the first instances of tools used for linear motion are the grape and olive presses found during archaeological digs of ancient sites. Ancients would turn a wood screw to move a platform in a linear motion. The platform would crush the grapes or olives to make wine or oil. The Industrial Revolution created a needed for better screws and actuators.

If you'd like to learn more about the history of linear motion visit this link.


Rotary motion is the most common method of creating linear motion in actuators, as well as in other instances.
Think about one of the oldest inventions of mankind: the wheel. A wheel uses rotary motion (it turns) to move in a
linear direction over a surface.


A lead screw actuator is made up of a number of parts that make it move:

  • Motor
  • Gears
  • Rod
  • Lead screw and nut
  • Power supply

The process begins with the power source. A power source can be either AC (alternating current, like a household
outlet) or DC (direct current, such as power from a battery). The power is supplied in a predetermined amount to
the motor, and the motor turns the gears. The last gear is attached to the lead screw, and when it turns, it turns
the lead screw. The lead screw is threaded through a nut, and that nut is attached to the rod. As the lead screw
moves, the nut pulls it upward or downward, and the rod moves, creating the linear motion.


Actuators have been used for many different applications and projects around the world. Manufacturing is a massive
user of these components for robotic and other processes. Some of the other industries that make use of them

  • Airplane
  • Automobile
  • Medical
  • Robotics
  • Aerospace
  • Construction
  • Engineering
  • Food and beverage
  • And many, many more

what's an actuator graphic

Unless you've been living completely cut off from modern society for the majority of your life, you've used a
product or service that has made use of linear motors. You may have even used one yourself during the course of your daily life. If you've used an electronic door lock system, you've used one.


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