Breakthrough to a wireless future
Updated on 08 June 2007
Scientists have demonstrated a simple way to transmit electricity through the air, raising the prospect of a world of wireless gadgets.
In the experiment, researchers lit a 60-watt light bulb from an energy source 7ft away using no power leads.
The research heralds a future in which mobile phones, MP3 players, laptop computers, and other appliances can be charged up without having to plug them into a wall socket. Some devices may even be able to operate without batteries at all.
The concept of "WiTricity", as the scientists have dubbed the technology, is not new. At the start of the 20th century, the American inventor Nikola Tesla dreamed of wireless power and conducted experiments showing how it could be done. However, the huge coils he used to generate electromagnetic fields only managed a very low level of power transfer.
The new approach described in the journal Science relies on two coils joined by a resonating magnetic field.
In principle the effect is similar to the transfer of energy that allows an opera singer who strikes the right note to crack a wine glass. If the glass is filled with just enough wine, it will vibrate at the same frequency as the singer's voice. Other glasses placed around it containing different amounts of wine will be unaffected, even if the soprano's voice is loud enough to shatter the resonating glass.
The magnetic coils used in the WiTricity experiment were coupled together the same way. One coil, attached to a power source, acted as the sender unit.
Instead of generating electromagnetic waves that radiate out and dissipate into space, it generated a non-radiative magnetic field of limited range. The field resonated with the receiver coil and induced a current to flow through it.
When the power to the sending coil was switched on, the light bulb connected to the receiving coil lit up even when objects were placed between them. The energy-transfer system was more than powerful enough to run a laptop over room-sized distances.
Professor Peter Fisher, who helped to conduct the research at the Massachusetts Institute of Technology (MIT) in Cambridge, US, said: "As long as the laptop is in a room equipped with a source of such wireless power, it would charge automatically, without having to be plugged in. In fact, it would not even need a battery to operate inside of such a room."
These news feeds are provided by an independent third party and Channel 4 is not responsible or liable to you for the same.
