CHAPTER 9. HOW WIRELESS CHARGING WORKS.
Let's look into one of the futuristic devices thatwe use today. As the name suggests; It just feels
awesome and unbelievable like magic to charge a phonewithout wire, right? Well, it's just use
of technology and nothing more.
Wireless charging is nothing but just transfer ofpower from your outlet to your phone without
wire. It's not a very new technology as it looks like.Nicola Tesla sort of invented it, almost 100
years ago, when he passed electricity through theair with the help of 2 copper coils.
For wireless charging, one needs a power transmittingpad and a receiver. Mostly the receiver is
embedded in the phone itself. It is because of theavailability of receivers that the mobile phones
are differentiated into wireless charging compatibleand non-compatible.
In physics, if the place of the observer is changedthen the way a problem looks changes. This
is analogous to the “wireless” word used here. Ifwe consider the charging of phones from the
outlet, then we can not say it is a completely wirelessprocess, because the transmitting pad
needs to be connected to the power outlet throughthe wire. But, if we consider the charging of
phones from the charging pad, then we can say it iswireless. So the whole process can not be
said to be wireless. It just means that we no longerneed to connect the wire to our phone to
charge, we can just place the phone on the pad andcharging starts.
Let us look at the way it works and how power getstransferred through the air.
So the transmitting pad and the receiver combinedcan be considered as a couple of
electromagnetic coils. The charging takes place byinduction method. In this method, one coil
produces a magnetic field around it, and the othercoil produces an electric current when in this
magnetic field.
When the charging pad is connected to the power outletelectricity flows in the pad. This
electricity produces the magnetic field because ofthe coil. The receiver in the phone is also an
electromagnetic coil which, when comes in the rangeof magnetic field, produces electricity by
the process of induction. The receiver coil is connectedto the battery of a mobile phone. So the
electric current produced charges the battery. Theinduction method used in the process
produced a large amount of heat. The temperature ofphones increases, and thus it is not a very
safe method of charging, but it is the most convenientmethod. Also, a lot of R&D is going on to
make it better.
It is very convenient to use because the transmittingpad can be embedded into the work table.
Whenever you keep the phone on the table, the phonestarts charging and hence you always