Home >Technology >Gadgets >Huawei just launched a smartphone that can wirelessly charge other phones. Here’s how it works

The Huawei Mate 20 launch event saw the unveiling of several products, which includes the quartet of Mate 20 smartphones, Huawei Watch GT and the Huawei Talk Band 3. While the theme of the entire event was to take everything that’s right with 2018 smartphones and make it better, there were a few unique innovations as well.

For instance, the Mate 20 pro can be we wirelessly charged via the Qi charging standard, no surprises there—but the smartphone can also wirelessly charge other smartphones as well. To make this stand out even more, the demonstration video showed an Apple iPhone XS being charged with the Huawei Mate 20 Pro. This feature is called “wireless reverse charging".

Huawei Mate 20 Pro charging an iPhone XS. Photo: Marques Brownlee/YouTube (MKBHD)
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Huawei Mate 20 Pro charging an iPhone XS. Photo: Marques Brownlee/YouTube (MKBHD)

Doing so is simple—just dig into the settings and enable the option and voila! You can let a friend charge their phone wirelessly.

While this is intriguing, it is important to note that this is slow, but hey, you can use those extra mAhs off your battery for the greater good, right?

If you’re wondering how this technology works, you might want to take a trip back to your school years and dig into that Resnick-Halliday textbook of Physics.

Wireless charging has a lot to with electromagnetic induction—the production of an electromotive force across an electrical conductor in a changing magnetic field. While this is the text book definition, let’s get real with it.

You might remember this as an experiment in which you moved a magnetic around a copper wire loop with a Galvanometer attached to its ends. The galvanometer needle moved whenever you moved the magnet, indicating the production of current wirelessly inside the copper loop.

The changing magnetic field in this case is the movement of the magnet, the electrical conductor is the copper wire and the electromotive force (or the voltage) is essentially the electrical intensity.

Now, the amount of voltage is determined by how fast the magnet moves, which in-turn determines how much current will flow across the loop (since voltage is directly proportional to the current in the circuit.

Let’s replace this magnet with an “electromagnet" or a copper coil with electricity flowing through it. The current flowing through the coil will in create a magnetic field (more precisely electromagnetic flux) and hence do the same thing you did by moving the magnet. Since this induces current in the copper loop, this can be called inductor.

Making an analogy with the real life scenario, a charging mat takes the role of the inductor (you can also call it the transmitter) while the setup on your smartphone can be called the receiver.

This is an oversimplified explanation—wireless charging is way more complicated than that, since it involves a lot of miniaturisation. You would remember from school days how big an electromagnet can get even if you created one with simple copper wires.

Wireless charging receiver module on Samsung Galaxy Note 9. Photo: Youtube (JerryRigEverything)
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Wireless charging receiver module on Samsung Galaxy Note 9. Photo: Youtube (JerryRigEverything)

Extending this setup to a larger set of wirelessly charging devices poses another issue—different devices have different voltage requirements. So setting a universal standard is important, just like how all wall sockets in India have more or less the same kind of design.

Here’s where Qi charging compliance comes into play, so you don’t have to go looking for a compatible charging pad for your device. There are also other kinds of universal standards, like AirFuel.

Coming back to our Mate (pun intended), the phone not only charges itself with a wireless charger, but also becomes one to charge other devices. Most devices only have the receiver part of the setup, which is smaller when compared to the transmitter. The Mate 20 accommodates the transmitter as well and that is where the genius lies—which is commendable.

Huawei hasn’t provided an explanation of how its charging/reverse charging mechanism works yet, but I’m definitely waiting for a teardown video of it to appear on YouTube.

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