[sdiy] Transformer question

[Theo]

While you have it open take a look at the PCB.
Its (probably) a single sided 2 layer board.
Think its done to save drilling cost compared to a normal dual sided 2
layer.

Cheers,
Theo


----- Original Message -----
From: Metzger, Michael A <MAMETZGER at partners.org>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Friday, July 23, 2004 4:47 PM
Subject: RE: [sdiy] Transformer question


> 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