Toothbrush Charger - How's it work?

This isn't really a home repair question, more a educational matter! We recently started using a Sonicare cordless electric toothbrush. The 'handle" fits in a recharger stand as expected - nothing unusual about that. The question is, how does this work? There are no contacts on the brush or in the stand! I'm sure it's not magic, but it is interesting! I wonder if this technology will find its way to cellphones and other rechargeable devices that still need contacts that get corroded.
Mark
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mwlogs wrote:

If there are indeed no contacts (are you -sure-" lol) then they're likely passing AC between the two pieces instead of DC, as is the case with most chargers. You can couple AC without physical contact if you orient the 2 pieces correctly and design them properly. That's how a transformer works. The wires from both sides of the transformer never actually touch inside the unit, they just pass current inductively because of the way they are arranged.
Just off the top of my head, I could see how that technology could crossover to other devices, but (again, just at first thought) there -might- be some reasons that you wouldn't want to try it with Radio Frequency devices like Cell Phones.
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mwlogs wrote:

Like a transformer, which it is. The wires don't touch but the lines of force from the AC current does.
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Like they said - it's a simple transformer. The primary windings are in the stand, the secondaries in the tooth brush so that they line up in close proximity when the brush is on the stand. The conversion to DC takes place inside the brush (diode or rectifier) where it chargers the battery.
John W

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This type of appliance is becoming more and more common. I have two different tooth brushes that work like this. You are right is just a simple transformer. Older types have a transformer and a rectifier in the base and toothbrush simply has electrical contacts and a battery. The new ones put all the stuff in the tooth brush except one half of the transformer.
John W wrote:

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