Wireless charger: how it works

You recently bought a new smartphone, noting the presence of wireless charging support. However, you have never approached this world properly and therefore you do not have the faintest idea whether this feature of your device can be useful or not.

Put simply, you are looking for information about how a wireless charger works , which can help you better understand this possibility. Don’t worry – there’s actually nothing that complex and this guide is right here to help you make your way through what’s available on the market.

In fact, in the following chapters I will focus not only on the general functioning of the technology, but also on those that today represent the most used solutions in this field. This way, in case wireless charging intrigues you, you can enter this world already aware of what’s out there. That said, there is nothing left for me to do but wish you a good read!


  • The electromagnetic induction
  • What does Qi mean
  • How a wireless charger works
  • How to choose a wireless charger
    • MagSafe
    • Caricabatterie wireless
    • Caricabatterie wireless 3-in-1

The electromagnetic induction

Before going into the merits of the matter and explaining all the details on how a wireless charger works , it is good to briefly mention the physical concepts that dominate this mechanism: since my goal is to make you understand everything in very simple terms, I intend to start with a example you have probably already dealt with: induction cooktops .

Induction kitchen hobs , those capable of cooking food without heating the cooking area at all (unlike glass ceramic hobs) exploit the principle of electromagnetic induction , the so-called Faraday’s law , for which the energy generated by the cooking area (ie the stove), in contact with the bottom of the pan, generates an electromagnetic field capable of activating the iron particles present in the pan itself. These particles heat the pan which, in this way, cooks the food contained in it.

For this reason, even if the pans are hot, the cooking zones of an induction hob are always cold (there is no heat transfer but energy displaced in a field). Furthermore, to take advantage of induction, the bottoms of the pots must be made of materials that can generate electromagnetic fields in contact with the hob.

But how does energy move from one point to another in an electromagnetic field? The secret is strength . To explain this with an example, think of two people stretching a rope (which you can imagine as an electromagnetic field): if one of these gives the rope a force, moving it to generate waves, these waves will also arrive on the other side of the rope. , without the second person making any movement.

The operating criterion of a wireless charger is very similar to what I explained to you a little while ago: thanks to the transfer via electromagnetic induction, it is possible to send the energy generated by the charging base (through the electricity that the base receives from the socket to which it is connected) directly to the battery of the device , by means of the special transmitter sensors placed on the base and receivers resident on the device.

Clearly, the larger the electromagnetic field, the faster the energy transfer. However, this does not mean that a larger charging base can power a battery faster: to avoid overload or physical damage to devices or even people, the manufacturers of chargers and smartphones limit the maximum voltage . In addition, the materials of construction of the devices can be a limit to the rate of induction transfer.

In short, in this first phase I explained to you in general how wireless charging works (the concepts are the basis of the technology itself, so it does not matter that you are asking, for example, how OPPO wireless charging works , how the charger works. IKEA wireless charger , how the Thun wireless charger works , how the Legami wireless charger works and so on). I have therefore provided you with basic information on how to use a wireless charger , while from now on I will focus more on the solutions available to you today.

What does Qi mean

Now that you understand how the power transfer between the charging base and the device works, it’s time to say a few more words about wireless charging. First of all, in this sector, the protagonists are two large organizations: the WPC (or Wireless Power Consortium ) and the PMA (or Power Matters Alliance ), both committed to perfecting and improving the aforementioned technology.

In particular, the WPC deals with managing the standards with which wireless charging is concretized and implemented by manufacturers: the most common of these is the Qi standard , used by the vast majority of manufacturers who use wireless charging, including Samsung , Nokia and Apple . Qi uses the electromagnetic induction principle seen a little while ago for recharging, and defines, in addition to the construction methods of the modules and sensors dedicated to the recharging bases and devices, also the safety standards aimed at preserving the safety of things and people (for example, avoid overheating of the parts involved).

The Qi standard, for charging to be successful, requires that the charging base and the sensor placed inside the device (smartphone, smartwatch, etc.) are very close to each other, at a minimum distance of 45 millimeters and a maximum of 400 mm , and perfectly aligned.

Thanks to this standard, over time, wireless charging has made great strides, almost completely eliminating the risks associated with its use and significantly reducing charging times, especially on the most powerful devices. Even the PMA technology , although less common, uses electromagnetic induction to carry out wireless charging, but with different criteria and hardware compared to the Qi standard. In short, there are several interesting solutions and clearly everything is evolving over time (so the details I have given you are only basic).

How a wireless charger works

If you have read carefully what I have explained to you in the previous chapters , the criterion behind the operation of a wireless charger should be quite clear by now, so it is time to move on to practice, explaining to you (this time without physical concepts, I promise) how you can actually take advantage of wireless charging .

In this regard, you should know that a wireless charger consists of a base , on which the device with a battery must be placed , and a power cable to be connected to the electric current. The base may contain rubber strips , useful for holding the device still, and on it there are one or more recharging points : marked with a symbol, these contain the energy transmitters which, upon coming into contact with the electronic device of to recharge the battery, generate the electromagnetic field predisposed to the transfer.

But how does the charger know that it needs to recharge a device? The explanation is quite simple: the transmitters placed on the base, at regular intervals, send a control signal to check the presence of the receivers installed in the charging devices. When the devices are detected (the signal comes back with different characteristics), the transmitters create an electromagnetic field with the receivers, to start immediately after induction charging.

How to choose a wireless charger

At this point, have you learned the basics of how a wireless charger works and so can’t wait to buy one? The first thing you should do, then, is to verify that the device in your possession is set up for wireless charging mode, as well as to keep in mind some parameters of choice that I am going to illustrate below.

  • Compatibility: Not all wireless chargers support both charging standards seen above. So, before purchasing, check if your device is compatible with the Qi standard, the PMA standard or both, and choose accordingly.
  • Shape: usually, the charging surface of such a charger is in a horizontal position and can be round, square or any other shape. However, there are some chargers that, to make it more convenient to use the device while charging, have a charging surface that can be positioned vertically.
  • Charging points: some chargers of this type have multiple charging points, i.e. multiple areas equipped with transmitters. However, this is not a guarantee of faster recharging, nor of the possibility of recharging multiple devices at the same time (currently it is not possible to do this): the receiver device must be compatible with transmission from multiple recharging points. However, I advise you not to opt for chargers with multiple charging points: at the moment, you would not find the use of it.
  • Batteriesand Additional Connectivity : Some wireless chargers have an external battery available, making them de facto wireless Power Banks.
  • LED indicators: on the market, wireless chargers are available with indicator lights, which allow you to check if the device is being charged.
  • Charging speed: an aspect that should not be underestimated is the speed allowed. On the market there are, for example, 5W, 7.5W, 10W and 15W chargers. The higher this value, the higher the charging speed (also depends on what is supported by the smartphone). Keep in mind, however, that generally wireless charging is slower than wired charging and you might be interested in this regard to my tutorial on how to charge your phone quickly .


If you’re wondering how Apple’s wireless charger works , this is the part of the guide for you. In fact, I am going to deepen MagSafe , which is the most recent solution of the Cupertino company.

It refers to a power supply originally launched with the iPhone 12 series , which is clearly compatible with the iPhone 13 and iPhone 14 as well . It is precisely with these ranges of smartphones that the accessory works as it should, as the magnets manage to line up with the back of the devices. Charging takes place at 15W .

However, I would like to clarify that the MagSafe power supply has support for the aforementioned Qi standard . This means that it is actually possible to use it for charging even with an iPhone 8 or later , although there is no magnetic alignment in this case.

I would also like to clarify that Apple has also placed the MagSafe duo power supply on the market . The latter allows you to charge a compatible iPhone and Apple Watch at the same time. Note the fact that the power supply can be folded up, although it might interest you to note that with models subsequent to the iPhone 13 line there are small alignment problems of the phone on the base (even if the correct charging of the devices is not prevented)

Speaking of Apple Watch , it should be noted that this uses a proprietary charging system and is not compatible with chargers other than Apple’s official ones (or chargers made specifically for it). More info here .

For the rest, it is worthwhile from my point of view to also dwell on the existence of the MagSafe Battery Pack . In this case, reference is made to a kind of wireless power bank , which aligns via magnets to the back of the iPhone 12 , iPhone 13 and iPhone 14 . With this product you can get an additional charge of between 40% and 70% , depending on the iPhone model you use. Among other things, using a Lightning cable you can transform the Battery Pack into a sort of 15W wireless charger . You may want to learn more about my tutorial onhow to charge an iPhone without cable for more details.

Caricabatterie wireless

Going beyond Apple’s official solutions , which can clearly come in handy if you own an iPhone, there are also many third-party wireless chargers on the market , with features like the ones mentioned above .

You may also want to take a look at my guide to the best wireless chargers in this regard , in order to make a more informed choice.

Caricabatterie wireless 3-in-1

How do you say? Do you have multiple types of technological devices and therefore would you need a charger for everything ? In this context, going beyond the classic chargers , I would like to let you know that over the years some third-party products have made their way onto the market that you may find interesting.

In particular, reference is made to 3-in-1 solutions (or in any case capable of charging several devices at the same time), which often act halfway between wireless and cable . To be clear, there are also products on the market that allow you to charge two smartphones at the same time , in addition to the smartwatch , but in reality only one of the two phones is charged wirelessly (while for the other a cable is connected, even if the latter is often hidden).

In short, in this case the single charger must be evaluated well , but I wanted to make you aware of the existence of this possibility, as indeed if you have many devices it could be useful.

Finally, I would like to clarify that at one time cases with integrated battery were also used , which nowadays are a bit obsolete (also due to the existence of solutions such as the aforementioned Magsafe Battery Pack ). This does not mean, however, that you cannot find some third-party proposals of this type on the market: perhaps you might want to take a look, for example, at some solutions that can be found in online stores such as Amazon.

by Abdullah Sam
I’m a teacher, researcher and writer. I write about study subjects to improve the learning of college and university students. I write top Quality study notes Mostly, Tech, Games, Education, And Solutions/Tips and Tricks. I am a person who helps students to acquire knowledge, competence or virtue.

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