Today I was experimenting with my Pixel phone’s ability to charge wirelessly, and wondering how it worked. So here are the fruits of my research: the short answer is “electromagnetic induction”.
The long answer is also electromagnetic induction, of course, but to get a bit more into the nitty-gritty of a pretty cool technology, you get electromagnetic induction when you move a magnet within a coil of wire, or a coil of wire within a magnetic field.
The reason is that current is just the movement of electrons, and when a coil of wire is moved in a magnetic field, the magnetic field ‘pushes’ on the electrons in the coil of wire, causing them to move. Tada! Current. And it’s “induction” because the current is “induced” by the movement.
In the case of a wirelessly charging phone, there’s a receiver coil in the back of the phone, and the wireless changing station creates the magnetic field.
It’s still slower than just plugging your phone into the wall, but if your phone is capable and you want to try it out without buying a wireless charger for yourself, you can go into a McDonald’s. In the UK, a lot of them are equipped with charging stations, including wireless charging pads! A small science experiment for the price of a cheeseburger…