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Is Laptop AC or DC? (Explained for Beginners)

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You know the electricity supplied to your home is an AC. Likewise, you are aware that there is another form of current called DC. You also know that some devices convert electricity from AC to DC before using it. But you are unsure if your laptop does this conversion before powering its complex circuits and operating system.

Also, you notice that there is an adapter attached to your charger and a battery affixed to your laptop, so you are curious to know if both the adapter and the battery work hand-in-hand to convert AC to DC for your laptop to use.

Don’t worry; your quest for knowledge has brought you this article, and it will satisfy your curiosity with accurate information. It will also let you know if your laptop can use either an AC or a DC without converting it.  

Is Laptop AC or DC?

You have seen me mention DC and AC repeatedly in this article already. If you are still wondering what these abbreviations mean, here is the answer: DC stands for direct current, and AC stands for alternating current. Both forms of currents are part of our everyday lives, and they have their peculiarities.

For example, a significant difference between the two currents can be deduced from their names. The direct current flows in one direction only, but the alternating current constantly changes direction as it is being supplied to the devices it powers for use. So which one does your laptop use? 

A laptop runs on direct current (DC) usually. With the battery intact, the type of current supplied to the integrated networks of circuits and processors which allows you to use your laptop for several functions is the direct current; this is because your laptop’s battery is a direct current generator, and it invariably supplies a direct current to your laptop to power it.

Why do laptops use direct current?

There are a few reasons why a direct current is preferred for your laptop over an alternating current. You must be made aware of these reasons so you are not tempted to make decisions that will harm your system. These reasons are:

Why do laptops use direct current?

Transistors and other unidirectional components

Laptops are built with several transistors and other components whose smooth functioning is permitted only by a unidirectional current. If an AC is used with such components, they may be damaged as alternating current switches between frequencies and voltages. And if the alternation between voltage is frequent, the parts mentioned above might blow up, damaging the entire laptop. Hence, a direct current is preferred.


We all want to be able to use our laptops after the power supply to our homes has been interrupted. And for this to be possible, our laptop needs batteries that will store up electric current for us to power our systems after the power holding company disappoints, and they usually do. So laptops are made with batteries. 

But these batteries cannot store alternating current. They can only store direct current. If this is so, it makes sense to build the laptop with parts that function best with a DC, which is the type of current that batteries supply. Using an alternating current with parts of a laptop built to be powered with a DC-generating battery might harm the laptop.

Frequency and voltage fluctuations with alternating currents

Most of the functioning parts of a laptop want a stable frequency and voltage supply, but an alternating current cannot guarantee this and hence can damage these parts; a good example of these parts is the logic circuits which help with the retention of stored information on laptops. 

A direct current is preferred for laptops over an alternating current to prevent this damage from happening.

Does my laptop battery use AC or DC power?

It is not out of place to want to be inquisitive about how a laptop battery can get charged by an AC. 

Well, a laptop battery is not charged by an AC but by a direct current because the presence of an AC adapter (the slightly heavy rectangular component of your laptop charger) ensures the alternating current from leaving the sockets in your home gets converted to a direct current before reaching the battery it charges.  

Can my laptop use AC only?

Having said that a laptop mostly runs on direct current, you are probably curious if your laptop can run on an AC without the need for its conversion and in what scenarios is this possible. 

The truth is it can. Your laptop, in some scenarios, can be made to function with an alternating current being the power source. You have likely used it with AC only without realizing it. Below are some of the scenarios:

Damage or unavailable battery

This can play out in different ways: 

  • your battery might be old
  • it might refuse to charge
  • you could perhaps borrow someone with the person not returning it, and you are pressed for time to complete a project on your laptop
  • it is possible you just deliberately removed the battery. 

In all these scenarios, if you are using your laptop connected to a power source without a battery, it means your laptop is functioning on AC only. But there are risks involved.

Setting a charge limit

This is another way to make your laptop start using AC only to run its operating system. I must remark that setting a battery limit is not a bad thing, though; it can help preserve the durability of your battery. But running your laptop on AC only might be harmful to the laptop.

Charging problems

A good example is when your laptop is connected to a power source, but your battery’s percentage keeps decreasing instead of charging. It is popularly called reverse charging. In this scenario, you might be tempted just to run your laptop on AC only, and it will function, but not without the following risks:

  • Losing unsaved projects: alternating current interferes with the function of the part that helps with storing information on your laptop, and running your laptop on an alternating current may cause the loss of unsaved projects.
  • Laptop’s operating system corruption: if you want to damage your device’s operating system rapidly, run it endlessly on alternating current while performing demanding tasks. Fluctuating voltages are not suitable for laptops because the parts are built to function with stable voltages. So anytime you use your laptop with AC only, you risk damaging its operating system. 

Final Thoughts

A laptop uses a direct current, and it has a battery that ensures this is so. But, though not advisable, certain situations may warrant running a laptop with an alternating current; by doing so, you are exposing the laptop to lots of harm.

As much as possible, keep your laptop running on a direct current. Always address the possible scenarios that might prevent your laptop from using a DC so you don’t experience the unpleasant reasons why the manufacturer didn’t want it to run on an alternating current.

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Pigtou Editorial Team

A group of tech enthusiasts who find pleasure in troubleshooting and resolving various issues. When we're not engaged in writing, we typically enjoy playing table football or spending time with our office dog.
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