After decades of fighting with tangled wires, being able to drop your device onto a charging pad is a gamechanger.

Electrons are clever subatomic particles. Push them along a wire and you’ve got electricity. Coil that wire, and you get a magnetic field – that’s how electric motors get their push. Put the coil near another one with a shared iron core to direct the magnetism, and power is induced in the second coil – that’s how transformers change voltages.

Pulse electrons through the coil and you can separate the other coil a little further away, enabling you to put the emitter in a charging pad, and receiving antenna in a phone. Bring the phone within range and it will have electricity induced in its coil by the electromagnetic pulses resonating from the charging pad.

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Dr Peter Bentley is a computer scientist and author who is based at University College London. He is the author of books including 10 Short Lessons in Artificial Intelligence and Robotics and Digital Biology: How nature is transforming our technology and our lives.

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