How Does Wireless Charging Work?

Just what is wireless charging? And why is a technology developed a century ago just now becoming popular? We talked to a few experts to find out.

Wireless charging as a concept has been around since inventor and physicist Nikola Tesla first concluded that you could transfer power between two objects "an electromagnetic field", said Ron Resnick, president of the Power Matters Alliance, that has a wireless charging protocol.

Essentially, wireless charging uses a loop of coiled wires around a bar magnet — which is known as an inductor. When an electric current passes through the coiled wire, it creates an electromagnetic field around the magnet, which can then be used to transfer a voltage, or charge, to something nearby.

Most wireless power stations nowadays use a mat with an inductor inside, although electric toothbrushes, for example, have long had wireless charging embedded in their bases. Because the strength of the electromagnetic field drops sharply with distance (as the square of the distance between the objects), a device must be fairly close to a charging station to get much power that way.

But although the basic concept of wireless charging has been understood for more than 100 years, scientists hadn't figured out a way to efficiently transfer large amounts of power using this technique.




Future uses

Nowadays, both the Power Matters Alliance and Wireless Power Consortium have developed competing protocols, or systems, for wirelessly charging devices. Existing systems are used primarily to charge smartphones or smartwatches. But wireless power may soon extend to many more applications.


As technology improves, it may be possible to charge bigger and more power hungry devices, such as blenders or even vacuum cleaners.