Optics Mag is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Read more.

How Do Projectors Work? Everything You Need to Know

Last Updated on


When you hook your computer or phone up to a projector, it magnifies the image and shines it onto whatever it’s pointing at. It might seem like magic, but there’s something a bit more scientific happening.

So, how exactly does a projector work, do you need a computer to work one, and are they more energy-efficient than televisions? We answer all those questions and more for you here.

shutter camera divider 2

How Do Projectors Work?

Projectors can work in two different ways. The first is by shining a light through a transparent lens, like a magnifying glass. This lens makes the image larger when the light shines through it, and the light projects it out the front.

With a traditional projector like this, the light is always white, and it filters through different lenses before projecting out. It does this through a complicated series of mirrors and prisms, and it can give you some of the best quality results!

While a traditional projector only uses white light, a laser projector uses three colored lasers, which are typically red, green, and blue.

The colors then go through a series of lenses where they’re mashed up into the right combinations to produce the image projected through the final lens! There are a few different laser projector types, with the primary difference being the laser color used to start with.

Some only use a single blue laser that is split into two beams and converted to a different color. From there, the beams go into a lens and a prism to get all the combinations that they need.

In short, projectors work via light, prisms, mirrors, and lenses. They use the light in precise ways to get the exact image that they need, and they shine it through the final lens that magnifies it out and onto whatever you’re watching!

Projector Screen
Image Credit By: Kuznetsov Dmitriy, Shutterstock

Can a Projector Work Without a Computer?

While most projectors use some sort of computer input device, not all of them do. Some work just fine with inputs like a USB, and they can project these files without any computer device.

However, it entirely depends on the projector that you’re using. Most projectors do require some sort of computer input. Even projectors that use different inputs, like smartphones or digital cameras, still use a computer input because that’s what is inside those devices.

Can You Connect a Laptop to a Projector Wirelessly?

This ultimately depends on the projector that you’re using. High-end projectors come with either Wi-Fi or Bluetooth capabilities, and you can often project from these devices wirelessly.

However, even if your projector has wireless capabilities, it doesn’t mean it can project a seamless wireless image for all situations. Streaming videos requires much more bandwidth than streaming pictures, and if the projector doesn’t have high enough capabilities, it won’t run smoothly.

Projectors with this capability do exist, but they’re expensive because it requires high-level technology to do the job.

projector on the table
Image Credit By: Piqsels

Does a Projector Use More Power Than a Television?

The answer to this depends on the type of projector and the type of television that you’re comparing.

There are many different types of projectors, and you can expect the hourly wattage to be anywhere from 10 to 800 for a projector. A television over 40” averages 234 watts per hour.

Generally, both battery- and LED-powered projectors use less power than a television, a DLP projector is similar, and a laser projector often uses more.

shutter camera divider 2


Projectors are a great way to get a large screen in an area that you don’t want to dedicate solely to a screen. They also often give you the ability to go even larger than you could with a regular television.

They don’t work through magic, but they do a great job of giving you a high-quality image!

Featured Image Credit: Frame Stock Footage, Shutterstock

About the Author Robert Sparks

Robert’s obsession with all things optical started early in life, when his optician father would bring home prototypes for Robert to play with. Nowadays, Robert is dedicated to helping others find the right optics for their needs. His hobbies include astronomy, astrophysics, and model building. Originally from Newark, NJ, he resides in Santa Fe, New Mexico, where the nighttime skies are filled with glittering stars.