What Adapters Do
When operating a laptop, constant access to an AC adapter is needed. Running on battery power, a laptop will only last a few hours at best. Add the fact that a laptop's lithium-ion battery naturally degrades faster over time and when it's exposed to heat (something a laptop produces plenty of), and you'll find that it needs to be plugged in almost every day. Universal AC laptop adapters provide the laptop's power supply with the energy it needs to run the computer and charge the battery. They come in a wide variety of shapes and sizes to fit almost any brand of laptop computer.
Choosing the Right Adapter
Keep in mind that all laptops come with a proprietary AC adapter that plugs into the wall. When shopping for a universal adapter, you'll see that there may be specific plug adapters to fit a wide range of computers. If you want to charge your laptop in your car, choose one with a car adapter. If you have multiple laptops, an adapter with interchangeable plug attachments will allow you to easily swap the adapter from one computer to the other.
Many universal laptop adapters offer automatic voltage switching, USB device charging and compatibility with MP3 and other portable music and video players. A quality adapter should also have an automatic shut-off safety feature if its internal temperature goes above a certain limit.
Where to Buy an Adapter
Universal laptop adapters are available at most big-box electronics or computer stores. Online retailers also sell a myriad of adapters and offer much more choice in features and price range. When buying online, however, keep in mind that you'll have to pay shipping costs, and the brands are often not as well-known as the recognizable brands of adapters found at your local store.
Generally, laptop AC adapters don't require much maintenance. If one stops working, however, it's a good idea to simply buy another, as repair would cost more. Since they deal with high voltages, it's not advisable to open an adapter and see what's wrong. It is normal for it to get warm during normal use, but if it's too hot to touch, consider replacing it to prevent future problems. Keep in mind that car adapters draw power directly from your car's battery through its cigarette lighter, so don't keep it plugged in for extended periods without running your car engine.