'WiTricity' powers unplugged lightbulb

 

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By Simon Aughton

Posted on 8 Jun 2007 at 12:08

A US scientist have succeeded in powering a lightbulb without wires. Marin Soljacic of the Massachusetts Institute of Technology made a 60W bulb glow by transmitting power via 'magnetic coupling'.

Marin Soljacic, an assistant professor in MIT's Department of Physics and Research Laboratory of Electronics, revealed last November that he had hit upon a method for transmitting electricity via a 'non-radiative' electromagnetic field. Scientists have known that electric power can be transferred wirelessly since 1831, when Michael Faraday discovered that current flowing through one wire induces a current in a neighbouring wire, but until Soljacic's discovery they had no way of safely directing the current.

The technique has been dubbed 'WiTricity' by the science community.

Soljacic's team lit the bulb using a power source 7ft away.

'It was quite exciting,' Soljacic, clearly a master of the understatement, said, adding that it was not a one-off.

'We can just go to the lab and do it whenever we want,' he said.

The next step is to improve on the current 40 to 45 per cent efficiency. Soljacic believes it will need to be closer to 90 per cent efficient before WiTricity can be used to charge batteries in portable devices, one of the applications to which he believes the technology will be most suited.

Soljacic insists that the 'magnetic coupling' poses no threat to humans - or animals. Nor does it appear to interfere with other electronic devices or magnetic media such as credit card strips and hard drives, though Soljacic said that more testing is required.