How Can An Electric Toothbrush Recharge Its Batteries
I got this question from one of my ERG members “how can an electric toothbrush recharge its batteries when there are no metal contacts between the toothbrush and the base? The answer is called inductive charging. Essentially, the toothbrush and the base form a two-part transformer, with the base having one part of the transformer and the toothbrush having the other. When you slide the toothbrush onto the base, the complete transformer is created and charge can flow.
The base contains one of the coils and the metal bar. The toothbrush contains the second coil. When you drop the toothbrush onto the base, you create the complete transformer! And this AC current will be converted to DC for charging the battery. This was a brilliant idea by the designer who purposely designed it so that the water would not enter through exposed contacts.