On 18/12/2013 15:23, pedro wrote:
On Fri, 13 Dec 2013 18:20:25 +0800, pedro wrote:

The Braun Triumph 3738 toothbrush and 3731 charger use an inductive
coupling arrangement to charge the toothbrush battery. Right now
SWMBO's unit isn't charging and I'm tasked with fixing it. Does
anyone know if this operates at line frequency or something higher?
(That will help sensing the field from the charging base to verify it
is operational before I disassemble the toothbrush itself.)

The techo guy at the authorised Braun service centre tested my charger
and confirmed it was dead as, so I purchased a replacement. He also
asserted that they do not contain any smarts, and operate at line
frequency.

For the benefit of others who may find themselves in this position,
the charger coil is driven at 72kHz unloaded, and this rises to 76kHz
when charging the toothbrush. So much for line frequency!

When I get a round tuit I may attack the dead unit with the trusty
Dremel to see what exactly is inside.

Thanks for all comments/suggestions.


See this EEVBLOG for insides of Braun toothbrushes. It is not line
frequency.
http://www.youtube.com/watch?v=JJgKfTW53uo

Chris