How to choose a power supply for your laptop?

Many people ask us how to choose a laptop power supply. If you would like to understand how to choose the power supply step by step, we encourage you to read our article. After reading it, you will become specialists in this matter!

A power adapter is usually treated with less care than the laptop itself, which often results in its damage. In the case of a broken cable or plug or if the device is lost, we are forced to buy a new equipment. But which power adapter to choose? You will find out by reading our guide.


To properly select the power supply, we must pay attention to the parameters and the type of plug it should have. The DC (direct current) parameters that interest us are:

The voltage of the power supply given in volts (V)

Have to match the value given on the laptop (in theory, the tolerance is about 1V, but not always).

The current measured in amperes (A)

is the value that determines the maximum current that can be charged to the power supply. This parameter should not be smaller than required, but it may be larger (according to the principle that you cannot have too much electricity). If you connect a power supply with a lower rate, you can even damage the computer because the components will not receive enough power.

Power in watts (W)

is the product of voltage and current. Like with the current, the power can be higher, because the laptop adjusts it automatically.


 The last thing which has to be checked before choosing a power supply. Currently, we can find dozens of different types of plugs, depending on the manufacturer and the laptop model. If we cannot get the data about the dimensions of the plug, simply measure it with a caliper and compare it with the dimensions of the new power supply plug. Remember that these dimensions are given in millimeters (mm). 

And now practice!

We have a Samsung NP-RC510, but unfortunately, the original charger has stopped working. On the power supply, we should find the model reference: AD-8019 and then check the OUTPUT and INPUT parameters. By the data from the OUTPUT (from the original power supply) or INPUT (from the nameplate located on the bottom of the computer), we find out that we will need a power supply with a voltage of 19V and a current of 4.74A. (remember that the current may be higher).

We have already checked the parameters – it’s time to choose the power supply plug. In the case of Samsung, the choice is quite easy – they have one end with a diameter of 5.5 mm – 3.0 mm (except ultrabooks, which may have a smaller diameter). If, however, we are not sure, then it is best to measure the inner and outer diameters with a caliper.

Having all the information needed, we start looking for a suitable product. In the search engine on the BatteryEmpire website, enter the brand of the power supply and parameters, eg Samsung 19V 4.74A and voilà – we have a properly selected power supply!

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