Chinese technology major Huawei has officially announced that it will bring to India only the Mate 20 Pro and Mate 20 RS Porsche Design out of the four Mate 20-series phones launched in London last month. The launch will take place on November 27 and it will be the first time a Mate-series smartphone will be launched in India. It comes with several interesting features and specifications, including the company’s Kirin 980 processor based on a 7nm process and the radially placed triple camera setup at the back.

One feature of the Mate 20 Pro, which is guaranteed to put a smirk on your face when showing it to an Apple or Samsung user, is wireless reverse charging.

While the Mate 20 pro can be wirelessly charged via the Qi charging standard, no surprises there—the smartphone can also wirelessly charge other smartphones as well.

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 textbook 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 a 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)
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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