A Laptop Ac Adapter Testing

An AC adapter, also referred to as a power adapter, provides power from an electrical outlet to a laptop. The power can be used not just to power the laptop, but to charge the rechargeable battery. If the battery is not charging or if the laptop is not powering on, one of the first things to troubleshoot or test is the AC adapter.
Remove the battery from the laptop. The battery is located on the bottom of laptops and is held in place with a latch. This latch can be released by sliding a latch or pressing a release button, depending on the brand and model of laptop you own. Once the latch is released, the laptop can be slid from the battery bay.
Press the laptop "Power" button one time. If the laptop turns on, the AC adapter is properly functioning. If the laptop doesn't power on, attempt using a different electrical outlet. If the laptop still won't power on, the AC adapter should be replaced
Insert the AC adapter jack into the AC adapter outlet on the laptop. The AC adapter outlet is a small circular hole, normally on either side of the laptop. Insert the opposite end of the adapter into an electrical outlet.
Connect the other end of the adapter to the laptop and turn the laptop on. When the computer starts up, you should see an indication of how the laptop is being powered in the lower right-hand corner. If you see a battery icon, then the laptop is being powered by the battery, not the adapter. Make sure both ends of the adapter are securely connected. If they are, and if the LED light on the adapter is lit, then you likely have a faulty wire that is not properly connecting to your computer. If you see a plug or adapter icon, then the laptop is successfully being powered by the adapter. If the LED light on the adapter is not lit, then the bulb is out, but the adapter is still working.
Plug the adapter into the wall outlet or power strip. If using a power strip, make sure the strip is on. Most laptop power adapters have a small LED light; the light will illuminate when power is being transferred from the outlet to the adapter. If the light illuminates, chances are you have sufficient power to supply your laptop.
Examine your power adapter. Every power adapter will have the input voltage and amperage requirements printed on it, as well as the output voltage and amperage rating. We'll be testing the output of the power adapter, so write down the specs. An example would be this, taken from a laptop power adapter: Output - 19.5V....3.34 amps. We'll measure the output of the power adapter with a multimeter -- a very handy tool for anyone working with electronics. A multimeter can measure voltage, current, power output and resistance of electrical circuits by touching the electrical circuits or device with a set of probes. See Additional Resources for a good tutorial on multimeters.
Check the data plate of your power adapter to find out which portion of the plug is positive and which is negative. For example, on some power adapter plugs, the outer shell of the plug is positive, while on others it's negative.
Set your multimeter to the proper range for measuring the output of your power adapter. Take into account the voltage and the amperage you'll be measuring. Consult the manual for specifics on how to set your particular model of multimeter.