Powermat – How does the Powermat wireless charger work?

PowerMat is an exciting new wireless charging technology. It was first demonstrated in 2008 and early 2009 and is now available to purchase for the home and office.

So what is PowerMat? It’s a small device that uses wireless charging to charge your most important devices like cell phones (including iPhone and Blackberry), video games (including Nintendo DS), and iPod without having to connect them to a charger or plug them into the wall. The PowerMat itself is of course plugged into the wall and connected to the mains via a cable, but from then on everything is wireless. You drop your device on the PowerMat and it charges wirelessly, without you having to do a thing.

So how does PowerMat wireless charging work?

The technology behind the PowerMat is known as ‘electromagnetic induction’ (or simply ‘magnetic induction’). Michael Faraday is generally credited with discovering the phenomenon of induction in 1831, although others were working in the same field at the time.

This electromagnetic induction is officially defined as “the production of voltage across a conductor placed in a changing magnetic field or a conductor moving through a stationary magnetic field,” but that doesn’t mean much to most people. A better way to say it is that it is a means of transferring electrical energy using a shared magnetic field.

Consider this arrangement:

1. Put electrical power into a coil of wire

2. This will produce a magnetic field around the coil that will affect any metal within the field (as demonstrated by Faraday)

3. Change the field rapidly over time and an electric current will be generated in the metal

So what happens when a PowerMat is charged is that it generates rapidly changing magnetic fields over the mat; these are converted by receivers in any device on the mat into electrical energy, and thus these devices are charged. Magnetic fields and electric currents are of course very small and can therefore work in portable devices without posing a health risk to humans.

The same technology is used in a host of other devices and systems, including generators, motors, transformers, some cookers, induction welding, etc. Perhaps the best-known example for most people is with rechargeable electric toothbrushes, where you are familiar with dropping a toothbrush into a “dock” every day to keep it charged. However, they may not be aware that similar systems also work on electric guitar pickups, VCRs, and computer graphics tablets.

The PowerMat is currently the best-known example of a wireless charger, but this technology is developing rapidly and we will soon see it in many other applications and products. The company PowerMat itself plans to extend the technology and present it on kitchen counters, walls and other surfaces in the home. One day this technology can be used everywhere and be invisible, it will be so common. Finally we will be freed from the endless tangle of chargers and cables around the home.