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Clarification on How Wireless Charging Works

  1. Jul 3, 2010 #1
    As far as I know, they use two coils and rely on a changing electromagnetic field to transfer electric current. So would wireless charging not work for DC current since a constant voltage would create an unchanging electromagnetic field and therefore unable to induce a current in the other coil?
  2. jcsd
  3. Jul 3, 2010 #2
    It's like a transformer, in principle. A changing current is required.
  4. Jul 5, 2010 #3
    But it's perfectly simple to convert DC to AC, transfer wirelessly, then convert it back.

    In fact it's often done by converting to DC, then to AC again at a more convenient frequency than mains cycles - do the wireless transfer, then rectify back to dc to charge a battery.
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