Attaching a second, external monitor to a laptop is as simple as plug, enable, and play. Nearly all laptops offer a VGA port that’s essentially identical in specifications to the output of the same port on a desktop computer. There are a few differences, though:
- Unlike on a desktop, a laptop system doesn’t automatically send a video signal to the external video port. You have to turn it on with a keyboard command or (less commonly) with a software command.
- The external monitor requires its own source of electrical power, almost always from an AC outlet.
- Although you can use the VGA port from a laptop running on batteries, it drains electrical power and shortens battery life.
Why would you want to use an external monitor?
- To make a presentation on a large monitor or projection system.
- To extend your output to a second screen. For example, as I write these words, my word processor occupies the LCD screen while I have a web browser running alongside. I can easily perform research and switch back and forth.
- To test or work around a failed LCD display.