Can electricity be transferred wirelessly? © iStock

Can electricity be transferred wirelessly?

So where did you put your charging cable?

Asked by: BBC Focus magazine


Yes, in fact that’s what happens when you recharge your electric toothbrush. There’s no wired connection between the base unit and the brush itself. Instead, they form two halves of a transformer, with electromagnetic induction transferring power from the coil in the base unit to that in the toothbrush.

Using the same principle across longer distances and higher powers is trickier, but a US firm, WiTricity, is working with a technique called resonant energy transfer. The idea is that energy is transferred more efficiently when the transmitting and receiving devices are both in resonance. WiTricity uses a transmitter coil producing an oscillating magnetic field. A receiver coil in a chosen gadget is tuned to resonate at the same frequency. Here, magnetism is being transmitted, rather than electricity. WiTricity has demonstrated the tech in gadgets like TVs. Other firms are using it in lower-power applications, like mats that charge phones. Soon, tangled power cables could be a thing of the past.


Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.