What is an Actuator?

An actuator is a device that makes something move or operate. It receives a source of energy and uses it to move something. Scroll down to learn more about what actuators are and various types of actuators.

Today we’re going to talk about actuators. There’s probably not a day that goes by where you don’t use or encounter an actuator at home, or at work.

In this article, we’re going to:

– Explain the purpose of an actuator

– Discuss the 2 different types of actuators

– Look at the 3 typical sources of energy required for an actuator to move something

– Observe the operation of an actuator used in a very common industrial control application

Everyday Examples

In very simple terms, an actuator is a device that makes something move or operate. Every one of us takes advantage of at least one actuator every day. Let’s look at some examples of actuators.

1. Grocery Store Door

When we go to the grocery store, the door opens automatically for us. An actuator makes the door open.

2. Car Seat

We can move the car seat forward or backward before we drive away in our car. An actuator makes the seat move.

Types of Actuators

1. Linear Actuator 

An actuator can move something in a straight line, also referred to as linear.

2. Rotary Actuator 

Also, An actuator can make something move in a circular motion, also referred to as rotary.

What Makes an Actuator Move?

We’ve talked about the movement of an actuator, but we haven’t discussed how, or what makes it move.

Actuators receive a source of energy and use it to move something. To put it another way, the actuator converts a source of energy into a physical-mechanical motion.

A butterfly valve is operated by turning the Handwheel connected to the rotary actuator. In industrial applications, the Handwheel could be replaced by one of three typical sources of energy, which can operate the rotary actuator:

– Electric actuators use some form of electric energy to operate.

– Hydraulic actuators use a variety of liquids as a source of energy.

– Pneumatic actuators are operated by compressed air.

Types of Actuators

Typical actuator types in the industry include:

– Electric Motors

– Hydraulic motors

– Pneumatic Control Valves

4-20 mA Pneumatic Actuator

Let’s look at a typical Pneumatic Actuator in action! The PLC analog output card produces a 4-20 mA current to move the valve from fully open to fully closed.

The 4-20 mA current will be converted to pneumatic pressure which becomes the source of energy to operate the actuator.


Let’s review what we’ve discussed.

– An Actuator is a device that makes something move or operate.

– An Actuator can move something in a straight line, referred to as linear, or in a circular motion, referred to as rotary.

– An Actuator receives a source of energy and uses it to move something. In other words, it converts the source of energy into physical-mechanical motion.

That source of energy can be in 3 different forms:

– Pneumatic

– Electric

– Hydraulic

Typical actuators in the industry include:

– Pneumatic Control Valve

– Electric Motor

– Hydraulic Motor

We hope you enjoyed this article on Actuator, here at RealPars our team of experts is on hand to answer your questions and respond to your feedback.

Also, we’d love to hear your suggestions for topics you want our team to cover.

Of course, if you’re serious about wanting to learn even more, you can gain instant access to a large number of exclusive RealPars courses covering a variety of industrial automation topics, including PLC and HMI programming, DCS, IIoT, and others, all for a small yearly membership fee.

It’s an amazing value for some really robust content and lots of support. And you’ll be getting the same course work that would cost you a few thousand for one week of offline training!

All of us on the RealPars team look forward to helping you continue to advance your PLC expertise and your career! 

Got a friend, client, or colleague who could use some of this information? Please share this article.

The RealPars Team
By Ted Mortenson

By Ted Mortenson

Automation Engineer

Posted on Feb 10, 2020

By Ted Mortenson

Automation Engineer

Posted on Feb 10, 2020

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