The Portable Mat
Taking a close look at the Portable Mat, you can easily see three distinct charging pads. Each of these is capable of charging a single device wirelessly. These pads use the principle of magnetic induction to move charging power from the pad to the device. This is one of the many principles of wireless power that Nikola Tesla proposed over one hundred years ago.
But the Powermat Portable Mat has a few more features besides the three charging pads. Along the back side of the mat, near the port for the power cable there is a single USB port. This can be used for wired power, making the single Portable Mat capable of charging four devices. There are also two buttons there; one controls the volume of the connection sound and the other controlling the LED charging indicator.
The Portable Mat can be folded up to store easily in the provided travel case, making this an easy choice for powering your devices on the go.
Internally the Powermat charging devices are very complex. When you place your device on a pad, it creates more than a magnetic "contact" for charging. Internally the receiver identifies the device and coveys this to the pad during its "handshake" phase. Once this is done the pad knows the amount of power to send the device. This allows the Powermat charger to stop charging once the device informs it that its battery is full.
This handy feature allows the Powermat to reduce the amount of power it draws from the wall and somewhat validates Powermat's claim of power savings when using it to charge electronic devices.