Why do induction charged electric tothbushed make a noise?

The various Braun Oral Bs' we have make a very faint creaking sort of whirring noise (while turned off) after being on their induction charger. You have to hold them close to your ear to hear it (well bay boomers like me who spent too much time in night clubs listening to load music in the 70's do) but as nothing should be moving inside why does it make this noise? There is a simple coil in the base of the toothbrush that which sit over the induction charger when it is seated in it. mainly just curious although I also have a dead one that no longer makes this noise and wondered if this was a clue to the cause (I have opened the dead one up and their was just a little moisture inside but no other obvious faults).

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Regards
Blue
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aussiblu
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Oops that should have been "toothbrushes" in the Subject Title

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Regards
Blue
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Reply to
aussiblu

Just tried it on mine, and yes it does make a noise. Mine is a series of "clicks" at maybe a 5Hz rate, very consistent. Weird. When I opened mine many years ago there was (from memory) just the coil, a diode, and an 8 pin SO chip, plus the battery.

Dave :)

Reply to
David L. Jones

I think you will find a capacitor and other components inside the coil making a filter. It will discharge slowly through itself and as it does it vibrates and makes a noise.

Reply to
DAC

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