Usually we may need two or more than two ac adapters for our laptop, because the original one is broken, lost etc. What’s more, it seems that we are more likely to buy the compatible ones online because of its cheap price and large selection. So it is important for us to know how to determine the correct power adapter since using one that isn't incompatible may result in severe laptop damage. Finding Sony VGP-AC19V17 AC Adapter[1]that fits my laptop is all about making sure that the power specifications match.

First of all, we should pay attention to the adapter’s plug size. Plug the AC power adapter into the power port of the device without plugging the other end to a power outlet. AC power adapters come in different shapes and sizes, so make sure that the AC power adapter plug fits the power port of the device. It should be totally the same as the original ones.

The other most important step we should do is: check the technical data of the original ac adapter on its cover. Check the voltage, current and wattage capacity of the device. A matching AC adapter should have a voltage capacity that is within 10 percent of the original one's voltage requirements, while the current should be equal to it or higher. atch the wattage specifications of the power adapter. The wattage should be equal to but not lower than the required wattage for the device.

Another important data should be the adapter’s plug size. Take my Sony VGP-AC19V17 AC Adapterfor example. Here is the specification of the original one:

Output: DC16V 4A Power: 64W Outlet: 2-prong Connecter size:

   Internal Diameter: 4.4mm
   External Diameter: 6.5mm 
   With pin inside

So when I am trying to purchase another new compatible one online, I would first make sure that the adapter I am looking for should have the connector size:4.4~~6.5mm; Then check the power, which should be 64W or larger than 64W. If I just make sure these two aspect as well as the same part number of these two ac adapters, I am sure the replacement one is exactly what I need.

I also once get the compatible Sony VGP-AC19V41 AC Adapterwith the above simple but useful tips.

So As soon as purchased the new compatible one, you could connect the new AC power adapter to a working power outlet to see if the device powers up or charges successfully.

For more laptop ac adapters and basic knowledge, you could visit:

Such as Sony VGP-AC19V15 AC Adapter (Input: AC100-240V (worldwide use) Output: DC19.5V 5.13A ) Sony VGP-AC19V30 AC Adapter(Input: AC100-240V (worldwide use) Output: DC19.5V 4.7A Power: 90W Outlet: 2-prong ) Sony PCGA-AC19V7 AC Adapter (Input: AC100-240V (worldwide use) Output: DC19.5V 5.13A ) Sony VGP-AC19V27 AC Adapter(Input: AC100-240V (worldwide use) Output: DC19.5V 4.7A Power: 90W Outlet: 2-prong )