How do electric toothbrushes charge through plastic casings?

[jimmy p]

How do electric toothbrushes charge? The ones i have seen are all plastic casings and the chargers are made of plastic, or at least the casing is. Obviously plastic is an insulator, so how does the charge pass through a plastic coating, and then through another?

Thanx

 

[chroot]

Magnetic induction. Energy is carried through an oscillating magnetic field.

- Warren

 

[chroot]

Originally posted by mmwave Why would they seal it up and use the less efficient magnetic induction?

It's not that much less efficient, and it's safer.

- Warren

 

[HallsofIvy]

The point is that one tends to use a toothbrush in a wet environment, often with wet hands.

 

[jimmy p]

...ok then, so the charger has a powerful electromagnet inside it? does the toothbrush have a battery pack or a capacitor inside it?

 

[chris229]

battery pack

 

[chroot]

Just think about a transformer, with one set of windings on one side of the plastic, and one set of windings on the other.

- Warren

 

[jimmy p]

ok cool, that sounds cool. I am suprised that is efficient though, to produce a strong enough magnetic field to induce a charge.