I guess as a broader question, how does wireless power transfer work in general and how are we able to transfer it from space, as I saw an article on it a while back.
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The movement of electrons and magnetism are very closely linked to one another. The right kind of magnetic field will move electrons (creating power) and the movement of electrons will create a magnetic field. It is a fundamental part of how both work.
This is how we generate most power today – _something_ causes a shaft to spin, and that shaft spins a set of magnets inside of a coil of wire. Those spinning magnets create a magnetic field, and the electrons in the coil of wire start moving. Almost all power generation is about _what we use_ to make the shaft spin – sometimes it is wind, sometimes it is boiling water to have steam make it spin, sometimes it is water flowing through a river, etc.
Wireless chargers create this magnetic field, which causes electrons in the receiver of your phone to move, generating power that the phone stores in the battery.
The issue is that magnetic fields are subject to the inverse square law – they decay _rapidly_ the further away you get from the source. They work well _enough_ over very short distances – the centimeter or so your phone is from the charger – but don’t work well at all over longer distances (even a few feet). The amount of power you’d have to put into generating the field would be orders of magnitude higher than what you’d get out of the receiver, making it pointlessly inefficient.
We’ll likely never be able to use magnetic fields to transfer power from space, but there are other technologies that may be able to do the job.
Surprisingly, the same way charging it with a cable does!
Inside the wall adapter there are two coils. One is at your 110V or 220V mains voltage. When two coils are in close proximity, power transfers between them, and it’s set up so that the other coil gets 5V or whatever happens to be needed. This is a huge simplification of course, but this is ELI5.
But the thing is, both coils don’t touch and aren’t connected to each other. All chargers are technically wireless. It’s just that some are a bit further apart and split in both pieces. Normally both coils are inside a single device. For a wireless charger half is in the charger, and the other coil is in the phone.
As for how that works, magnets. One coil turns electricity into a magnetic field, and the other picks up the magnetic field and makes it back into electrical current.
I’ll start by saying that phone wireless charging and beamed power from space are different technologies.
Your phone uses something called “induction charging”. This uses two laws of physics: 1. An electrical current produces a magnetic field and 2. changing magnetic fields generate electrical voltage.
Your wireless phone charger has a wire loop or coil that it passes a changing electric current through, so this produces a changing magnetic field around it. Your phone has a loop or coil in it, that reacts to this changing magnetic field by producing a current that can be used to charge your battery.
I’m not a expert in beamed power, but I believe current proposals basically use the same principle as solar panels: On the sending side use a laser to turn electrical energy into light energy, and on the receiving side, use photovoltaic cells (solar panels are made of these) to turn light back into electricity.
magnetics.
if you remember making a magnet with wire, a nail, and a battery that is the basics
the charger has a coil of wire that Turns on and off” rapidly.
that tuns the magnet on and off.
meanwhile your phone has a coil of wire that converts that magnet power back into electricity
and that charges the battery
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