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Practical Computer Advice
from Martin Kadansky
Volume 7 Issue 7
July 2013
Can I Add A Second Monitor To My Computer? What About A Projector?

Do you wish your computer monitor were bigger? Are you constantly shuffling your windows around, juggling your email, web browsing, documents, and spreadsheets? Consider adding a second monitor to your computer, it's never been easier!

Have you wanted to make presentations to a roomful of people, but been confused about how to connect a projector to your computer? Good news--It's practically the same as adding a second monitor!

Where do I start? Look at your computer
The first thing you have to find out is whether your computer already has a video "port" (and the hardware circuitry behind it) where the second monitor or projector will connect, or whether you'll have to add it. Here's a quick guide:
  • Windows desktop computer: It varies. Some machines have multiple video ports already built-in, but for those that don't it's inexpensive and easy (for a computer person) to add a video card to give you a second video port to plug in a second monitor. If you're ordering a new computer, ask before you buy. If it's a computer you already own, look for multiple video ports, check the specifications (if you can find them), ask the vendor you bought it from, or talk to a computer person.
  • Windows laptop: It probably already has a built-in video port for an external monitor. VGA ports have been the most common for many years, newer laptops might have a DVI or HDMI port. Look around the edges of your laptop, or have a computer person take a look.
  • Macintosh desktop or laptop: A video port for an external monitor is standard, you'll probably just need an adaptor. Thunderbolt (Mini DisplayPort) and HDMI ports are common on current models; older models had a variety of ports, including DVI, mini-DVI, and VGA.
My computer can handle a second monitor! How do I connect them?
Once your computer has a video port (and the circuitry behind it) to support a second monitor, you'll need to know two things:

1. The type of the video port (output) on your computer you'll be using for the second monitor. The most common are:
  • Windows: VGA, DVI, DisplayPort, HDMI
  • Macintosh: DVI, mini-DVI, Mini DisplayPort, Thunderbolt
2. The type(s) of video port(s) on your second monitor or projector (input). The most common are VGA, DVI, and HDMI. It's common for newer monitors to have multiple types of video ports. (It's also common for newer televisions to have computer-compatible video input ports, so if it's a recent model, your TV is also likely to work as a computer monitor!)

Once you have this information, you can figure out how to connect them:
  • If an available video output port on your computer matches a video input port your second monitor (e.g., they both support VGA), then you can simply plug your second monitor directly into your computer using a single video cable.
  • If none of the ports match, you'll need an adapter. For example, if your computer has a Mini DisplayPort but your second monitor only has a VGA port (a common situation with a Macintosh), you'll need to buy a VGA-to-Mini-DisplayPort adapter and use it in conjunction with your VGA cable.
I've connected my second monitor or projector to my computer, how do I use it?
Computers have two main "display modes" when an external monitor is connected:
  • Mirroring: The secondary monitor shows the same image as the primary
  • Extended desktop: The secondary monitor is independent and provides additional working space.
Mirroring is the right choice when connecting a projector, or for comparing two monitors, or for using two monitors to give a presentation in a large room to more people than can fit around one monitor. Mirroring will also make both monitors (or your monitor and your projector) to use the same resolution, which means that the resolution on the higher-resolution device will be lowered to match the lower-resolution device while mirroring is in effect.

However, if you have a second monitor, most of the time you'll probably use it to create more working space on your computer instead. Here's how that works:

With mirroring off, you'll choose one of your monitors as the "primary," which will make the other one "secondary." Your primary monitor will have:
  • Windows: The Taskbar (most commonly located across the bottom)
  • Macintosh: The menu bar (across the top) and the Dock (most commonly located across the bottom)
Note that the choice of which monitor is "primary" and which one is "secondary" is entirely up to you. Your desktop's original monitor or your laptop's built-in monitor can be "secondary" if you want.

Also, since your computer can't know how your monitors are physically arranged on your desk, you'll have to tell it by choosing the "edge" along which your two monitors will "touch." For example if your primary monitor is on your left and your secondary is on your right, you'd "arrange" them in a similar way using the software, so that as you "fly" your mouse off the right edge of you primary monitor it enters your secondary on the left. That's how you'll move icons and windows over to your secondary monitor as well.

Once you've done all this, your windows will initially open on your primary monitor, but you can drag them to the other monitor (and back) if you choose. Many programs will "remember" that you like to have their windows on your second monitor.

To adjust your monitor settings for mirroring, resolution, physical arrangement, and more, after connecting both monitors you would go to:
  • Windows: Control Panel->Display
  • Macintosh: System Preferences->Displays
Pros and cons of having two monitors
Having two monitors is great! Since you'll have a larger working area, you can have more windows open that don't get covered up, and you'll spend less time shuffling windows and probably be more productive. For example, you could have your email on one monitor and your documents and web sites on the other.

  • Another monitor takes up more desk space, and its power and video cables add to the mess of cables you've probably already got.
  • If your monitors operate at different resolutions, then they'll probably display things at different sizes. Also, the "edge" where they "touch" may not span the entire height, making it occasionally awkward to move your mouse from one to the other.
  • You'll probably see the same desktop background picture (or color) on both monitors. It's possible to have a different desktop picture on each monitor, but it takes a little work.
  • If one of your monitors is newer than the other (and probably better and brighter), having them side-by-side might make the older one seem a little shabby.
  • If you have a laptop and you travel with it, leaving your second monitor at home, its video cable will be one more cable you'll have to connect and disconnect each time.
  • While many remote-help services (LogMeIn, join.me, GotoMyPC, TeamViewer, etc.) support multiple monitors, some of them require an extra step before your helper can see your other monitor. So, if you have someone help you remotely over the internet, be sure to tell them if you have a second monitor.
However, for most people these are minor considerations compared to the fun and productivity of having two monitors.

Can I use an external monitor with my laptop and close its lid?
If you have a laptop, rather than using both the internal monitor and an external monitor at the same time, you might just want to use a larger external monitor by itself. Windows and Macintosh laptops both support this, and it only takes a few minutes to set up. Also, closing the laptop's lid (or leaving it open just a little for ventilation) will mean that you'll need an external keyboard and mouse, and you'll probably need to keep the laptop's power cable plugged in as well.

What about a projector?
Connecting a video projector to your computer involves exactly the same steps as connecting a second monitor. In fact, your computer can't tell the difference! You'll choose the mirroring option, so your biggest issues will probably be picking the best resolution and getting good image focus on your projection screen or blank wall.

Here's a tip: Instead of putting your projector on a table and tilting it upwards so your audience can see the projected image, elevate your projector higher than table height (put it on a cardboard box, suitcase, or pile of phone books) so you can keep it level, which minimizes any distortion in the image.

Adding a second monitor or projector to your computer is pretty straightforward. Your computer needs to support two monitors, you'll need the right cable (and possibly an adaptor), and then you'll need to adjust the software settings to suit you.

If you're torn between buying a desktop computer vs. a laptop (or buying one of each), buying a laptop and adding an external monitor can give you "the best of both worlds."

Be careful what you wish for, you'll be looking into adding a third monitor before you know it!

Where to go from here
How to contact me:
email: martin@kadansky.com
phone: (617) 484-6657
web: http://www.kadansky.com

On a regular basis I write about real issues faced by typical computer users. To subscribe to this newsletter, please send an email to martin@kadansky.com and I'll add you to the list, or visit http://www.kadansky.com/newsletter

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Copyright (C) 2013 Kadansky Consulting, Inc. All rights reserved.

I love helping people learn how to use their computers better! Like a "computer driving instructor," I work 1-on-1 with small business owners and individuals to help them find a more productive and successful relationship with their computers and other high-tech gadgets.

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