Step 1- Disconnect the power power cord.

Disconnect the plug from the wall and the computer as you will be testing the wires for continuity.

Step 2- Disconnect the power cord from the AC adapter power supply.

Disconnect the power cord side from the AC adapter side. Now you have two separate pieces, the power input cord, and the power supply with the thinner cord that plugs into the laptop.

Step 3- Test resistance though the plug prongs.

Connect your meter while in the Ohms setting to the two main prongs on the power cord. With the cord isolated from the power supply, you should get an open or infinite Ohms. Note: If your adapter does not disconnect in the middle, then you will be reading through the power supply, but you should still get an open on the test.

Step 4- Read from plug ground to outer shell of laptop side.

Connect the power cord and laptop AC adaptor together again. Connect one meter lead to the ground prong of the wall plug, and the other meter lead to the outer shell of the laptop side plug. You should get a reading of continuity here, or zero Ohms. If you don’t, then your ground is defective.

Step 5- Be sure the cord is not plugged into the power outlet.

STOP: Make sure the cord is not plugged into the wall, severe shock could occur or meter damage.

Step 6- Jumper the inner contact of laptop side.

Make a jumper wire that will fit into the adapter tip. You can also wrap a piece of safety wire around the meter lead, and use that to insert into the contact.

Step 7- Test for a short on laptop side contact.

Check for a direct short between the outer shell and the inner contact of the laptop side plug. You should read an open on this measurement.

Choosing the best laptop network  AC adapter depends a great deal on what exactly you need from an adapter and how much experience you have with installing new hardware into a laptop. In general, it is usually a good idea to avoid installing or removing any hardware into or from a laptop unless you are experienced with laptop modification. For the most part, you should try to use devices that connect externally, usually through a universal serial bus (USB) port. You should then determine whether you need a laptop network adapter for a wired or wireless network, and once you know this you can easily find a good adapter in whatever price range you desire.

While you can purchase and install a laptop network adapter inside of your laptop, this is usually a fairly complicated process. Unless you have extensive experience working with laptops, it is generally inadvisable to make alterations inside the case. Even if you have experience working on desktop computers, you may want to avoid trying to make hardware installations on a laptop, since doing so may void any warranties on your laptop. This means the best option for most people will be an external laptop network adapter, and knowing what type of adapter you need will make choosing the best one for you easier.

In general, there are two basic types of  laptop AC adapters devices: those for use with a wired network and those intended for wireless networking. Either type will typically connect to a USB port on a laptop, so be sure you have an available port. Many laptop users will use a separate mouse that is often connected to the USB port on a computer, and printers or external display devices may also use USB ports on your laptop.

A laptop network adapter that is intended for wired use will simply be an Ethernet connector that can be plugged into a USB slot on your laptop. It is worth noting that many laptops come with an Ethernet port and you should be sure that you do not already have such a port before buying an adapter. A wireless network adapter for a laptop will usually connect to a USB port and allow the computer to connect to a wireless network.

Many new laptops are built with an AC  adapters, and you should be sure you do not already have  connectivity before purchasing a AC  laptop network adapter. You should look for product reviews on Internet technology sites and find an adapter that is well reviewed by professionals and customers as well. This type of device will usually be fairly inexpensive, though high-end USB adapters can be more expensive, but often provide higher performance.

Choosing the correct laptop adapter is all a matter of voltage, output power, and proper connection. If all of these things do not match the original specifications of your computer, than a new laptop AC  adapter will likely not work on your machine and may potentially cause a lot of damage. In the end, most replacement power adapters will have a list of computers they are compatible with.

The first thing to consider for the laptop power adapter is the voltage. The easiest way to check this is to turn the computer over and see if there is a voltage listed anywhere on the bottom of the machine. A sticker may be affixed with this information and other similar laptop specs listed. It should be a number with a V attached to it, such as 19.5V. This information is also available on the original adapter, if it is available.

The second thing to look for is the current output needed for the laptop  AC adapter. This number will have an A of mA associated with it. For example, it may say something like 4.7A or 950mA. These numbers ensure that the power going to your machine will be acceptable and keep it operating within normal parameters. Not paying attention to either of these numbers could cause the electrical systems in the computer to malfunction and quit working altogether.

Once these two issues have been settled, the other important step is simply to make sure the connection fits the port in your computer where it is to be plugged in. The voltage and output current of the laptop adapter will not matter if it is not able to be connected. If ordering online or if you do not have your computer, it is advisable to check this out as soon as possible.

Many may choose the safest route possible and go with a replacement laptop adapter directly from the manufacturer, if available. While this is a good option, these parts may be more expensive than others that may be available from after-market manufacturers. Further, as long as the numbers match, all should work nearly the same and be just as safe and effective.

Another thing to consider is whether you want an AC laptop adapter or DC adapter. An AC adapter is made to be plugged into any standard electrical outlet such as those in a home or office. The DC adapter is made for automobile use.

Typically, laptop adapters can be found for sale anywhere computer accessories or laptop batteries are sold. Though the price will depend on the model and manufacturer, most tend to run between $40 US Dollars (USD) and $100 USD. They are also available from many online retailers as well.