[sdiy] Transformer question

[Harry Bissell Jr]

I'd take a small coil of wire, and a scope and see if
I could "sniff" any of the flux leaking. It may be
that
the thing has a switching power supply and the
frequency
is MUCH higher than you think, which would make the
circuit work without much, or any core...

H^) harry



--- Scott Gravenhorst <music.maker at gte.net> wrote:
> I would bet that there is an iron core in the
> handle.
> 
> Although this is interesting and quite curious, what
> is wrong with a simple plug
> and jack arrangement to power a music device?  I can
> see the advantage for
> something like a toothbrush or electric shaver since
> these devices can get wet so
> the use of magnetic coupling is an advantage against
> corrosion.  But we don't
> normally use our music equipment in the shower. 
> While this would be "cute", I
> don't see it as very practical for musical use.  It
> will wind up being rather
> expensive and inefficient compared to a simple plug
> and jack.  Perhaps effort
> toward the actual circuit would be better expended
> for a good "gee-whiz" effect,
> assuming that "gee-whiz" is the goal.
> 
> 
> 
> "Metzger, Michael A" <MAMETZGER at partners.org> wrote:
> >I was able to pop the bottom off the toothbrush
> handle last night. Believe it or
> >not, inside was as I thought - an air core coil. It
> is oriented to fit over the
> >nub on the base. I was surprised at how large the
> diameter of the air core was.
> >The engineer was definitely not concerned with
> making it fit tightly around the
> >nub. Four leads from the coil go farther into the
> handle to a circuit board. I
> >could only see the edge of the board as it was
> wedged next to the battery.
> >
> >An interesting detail is that above one side of the
> coil are two tiny metal
> >cylinders. Theyblook like magnets. The metal is
> soft - I chipped one slightly.
> >They are about 2mm in diameter, maybe 3mm long. The
> cylinders are next to each
> >other and are oriented vertically, the same as the
> coil. They are not in the
> >core but are 3mm or so directly above the loops on
> one side of the coil.
> >
> >So according to everyone's comments it sounds like
> efficiency is low. The handle
> >sure is warm every time I pick it up. But hey - the
> circuit works.
> >
> >Mike
> >
> >
> >-----Original Message-----
> >From: owner-synth-diy at dropmix.xs4all.nl
> >[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf
> Of Metzger, Michael
> >A
> >Sent: Thursday, July 22, 2004 8:54 PM
> >To: synth-diy at dropmix.xs4all.nl
> >Subject: RE: [sdiy] Transformer question
> >
> >
> >So my quick and dirty "circuit" isn't sound? Uh, no
> surprise there (look at
> >ground, cough)  You guys have got me wanting to
> take the toothbrush apart now. A
> >quick glance when I bought it showed the handle
> part to be put together pretty
> >well. I don't want to break it. Maybe I can get
> into the base, though. Maybe
> >something for this weekend.
> >
> >Mike
> >
> >
> >-----Original Message-----
> >From: owner-synth-diy at dropmix.xs4all.nl
> >[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf
> Of Paul Perry
> >Sent: Thursday, July 22, 2004 7:45 PM
> >To: synth-diy at dropmix.xs4all.nl
> >Subject: Re: [sdiy] Transformer question
> >
> >
> >You need a closed (or as closed as possible)
> magnetic loop,
> >and for any kind of efficiency that means a core of
> >transformer iron or similar.
> >All I can imagine working, is two U sections, with
> the tops
> >of the Us facing each other across the gap.
> >(or, similarly, a number of these).
> >
> >Although, the 'receiving' side could simply be a
> slab of 
> >'lossy' magnetic material, if you were just boiling
> water.
> >
> >paul perry Melbourne Australia
> >
> 
>
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