How Does Wireless Charging Work?

Dec 7, 2017 By Mehek K, Writer Intern
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You may have noticed that the newer smartphones on the market like the iPhone X boast a feature they call ‘wireless charging.’

Although this may seem like a new and futuristic concept, it may surprise you to find out that induction -- the science that drives wireless charging, has actually been around for many years.

It is used in cutting cables, kitchen appliances, and even the electric toothbrush you use every morning!

Let’s take a look at the science of induction.

The Science of Induction

Imagine a coil of wire that is connected to a galvanometer (a device that measures electric current). Note that there is no battery connected to the wires. Now move a magnet towards and away from the coil. You will be surprised to see that the galvanometer registers a current flowing in the coil!

Just as a moving magnet can create electricity, the reverse is also true -- a changing electric current (known as alternating current or AC) flowing through a wire will produce a magnetic field around it. This principle of how electricity creates magnetism, and magnetism produces electricity, is called electromagnetic induction and was first discovered by Michael Faraday, a brilliant English physicist. 

You can see electromagnetism in action every day in the electric cooktop in your kitchen. When current flows through the coil under the glass cooktop surface, it produces a magnetic field. This magnetic field induces an electric current in the metal pot that sits on top of the glass, which heats up the food inside.

So how does this relate to our wireless charger? You guessed it -- the charging pad and the phone, each have a coil of wire. The coil in the charging pad is known as a transmitter coil and it is connected to the power outlet. When current flows in the charging pad, it induces a current in the receiving coil inside the smartphone. 

The Future of Induction

There are many advantages to inductive charging such as being able to charge anywhere, allowing multiple devices to be charged on the same port and making phones waterproof. However, there are some disadvantages as well. It takes more time to charge wirelessly than it would with a wire, and phones cannot be moved while charging wirelessly. Also, a charging port will not work across all wireless devices -- which is why a company that makes the phone has to make the wireless charger as well. 

When a new technology is introduced, often companies will work together to develop a standard that makes it easy for customers. Companies such as Samsung, Sony, Apple, Nokia, Motorola, and HTC are working on creating a wireless charging port they call Qi that will become a standard across the different types of phones. Apple has already included a version of the Qi charger with their iPhone X.

Even though wireless charging is in the early stages, we may see more applications in the future. It could be used in medical devices and in parking spots for charging smart cars. We may even see electrically charged highways that charge electric cars as they move!

This simple video shows how a bulb lights up without a wire!

Sources: HowStuffWorks, explainthatstuff.com, powerbyproxi.com