Electric Toothbrushes: Charging Plastic Casings

  • Thread starter jimmy p
  • Start date
  • Tags
    Electric
In summary, a toothbrush has a battery pack or capacitor inside it that is charged by an electromagnetic field.
  • #1
jimmy p
Gold Member
399
65
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
 
Physics news on Phys.org
  • #2
Magnetic induction. Energy is carried through an oscillating magnetic field.

- Warren
 
  • #3
Originally posted by chroot
Magnetic induction. Energy is carried through an oscillating magnetic field.

- Warren

Why? I haven't had one since I was 7 (I won't say how long ago that was but it was a long time). It had two little metal prongs that made contact with sockets in the brush for charging. Why would they seal it up and use the less efficient magnetic induction?
 
  • #4
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
 
  • #5
The point is that one tends to use a toothbrush in a wet environment, often with wet hands.
 
  • #6
...ok then, so the charger has a powerful electromagnet inside it? does the toothbrush have a battery pack or a capacitor inside it?
 
  • #7
battery pack
 
  • #8
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
 
  • #9
Originally posted by 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

Ok, but transformers are generally wound sharing the same core and in this case it's not possible, hence less efficient than a normal transformer.
 
  • #10
ok cool, that sounds cool. I am suprised that is efficient though, to produce a strong enough magnetic field to induce a charge.
 
  • #11
It actually induces current and EMF. Look up Faradays law of induction.

It doesn't matter if there is a conductor in the way of the electromagnet or air, EMF will still be produced (mathematical path). However, in this case, there is a conductor with N turns in the path of the magnetic field, which will carry induced current and induced EMF. This induced EMF charges the battery inside the plastic.

M2k
 
Last edited:

1. How do electric toothbrushes charge?

Electric toothbrushes charge by plugging them into an electrical outlet. The charging process usually takes a few hours and once fully charged, the toothbrush can be used for multiple brushings before needing to be charged again.

2. Can electric toothbrushes be charged with a USB port?

Some electric toothbrushes can be charged with a USB port, but not all models have this option. It's important to check the product specifications or manual to see if your electric toothbrush is compatible with USB charging.

3. How long should an electric toothbrush be charged for before use?

The recommended charging time for an electric toothbrush varies between models, but it usually takes between 8-16 hours for a full charge. It's important to check the product manual for specific charging instructions to ensure the battery is not overcharged, which can decrease its lifespan.

4. What type of plastic is used for the casing of electric toothbrush chargers?

The type of plastic used for the casing of electric toothbrush chargers varies between models and manufacturers. However, most commonly used plastics are ABS (Acrylonitrile Butadiene Styrene) and PC (Polycarbonate), which are durable and impact-resistant.

5. Can electric toothbrushes be overcharged?

Yes, electric toothbrushes can be overcharged if left plugged in for an extended period of time. This can lead to decreased battery life and performance. It's important to follow the recommended charging time and unplug the toothbrush when fully charged to avoid overcharging.

Similar threads

Replies
6
Views
849
Replies
4
Views
936
Replies
2
Views
319
Replies
17
Views
1K
Replies
22
Views
752
Replies
1
Views
981
  • Electrical Engineering
Replies
6
Views
969
Replies
73
Views
3K
  • Electromagnetism
Replies
7
Views
2K
Replies
11
Views
294
Back
Top