About Powered USB Hubs
A powered USB hub works in an identical manner to one that draws its power from the main computer, except this variety is powered directly from the mains supply. Although many modern PCs, Laptops and Macs are supplied with a number of USB sockets, there will usually be a set limit to the amount of devices that can be attached at the same time. The main part of the system will only be capable of providing power to external peripherals to a certain point - once this limit is reached, certain devices will cease to function. A powered USB hub can be used to get around this problem, as its power needs are satisfied by an external source.
Powered USB hub devices work by attaching themselves to an existing USB port, splitting the connection between a set number of integrated USB sockets. Because of the external source of power, all devices will continue to function - even when all sockets are occupied by peripherals. It is important to pay close attention to the USB standard that is displayed on the hub, as this will determine the maximum speed of data transfer (USB standards are all backwards-compatible). Some USB hubs may be incompatible with Mac computers, so it is also a good idea to check the exact hub details before buying.
While powered USB hubs are suitable for connecting large numbers of devices, they are also ideal for single devices that have excessive power demands. Tablet computers are notoriously power-hungry, and if they cannot be charged in a regular USB connection, this powered accessory may be the solution.