[sdiy] Transformer question

[Scott Gravenhorst]

Harry Bissell Jr <harrybissell at prodigy.net> wrote:
>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

This is very true, aircraft use 400 Hz power and it does
reduce the transformer weight.  



>
>--- 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
>> >
>> 
>>
>---------------------------------------------------------
>> - Where merit is not rewarded, excellence fades.
>> - Hydrogen is pointless without solar.
>> - What good are laws that only lawyers understand?
>> - The media's credibility should always be
>> questioned.
>> - The only good terrorist is a dead terrorist.
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>> 
>> -- Scott Gravenhorst | LegoManiac / Lego Trains /
>> RIS 1.5
>> -- Linux Rex         | RedWebMail by RedStarWare
>> -- FatMan: home1.gte.net/res0658s/FatMan/
>> -- NonFatMan: home1.gte.net/res0658s/electronics/
>> -- Autodidactic Master of Arcane and Hidden
>> Knowledge.
>> 
>> 
>

---------------------------------------------------------
- Where merit is not rewarded, excellence fades.
- Hydrogen is pointless without solar.
- What good are laws that only lawyers understand?
- The media's credibility should always be questioned.
- The only good terrorist is a dead terrorist.
- Governments do nothing well, save collect taxes.

-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
-- Linux Rex         | RedWebMail by RedStarWare
-- FatMan: home1.gte.net/res0658s/FatMan/
-- NonFatMan: home1.gte.net/res0658s/electronics/
-- Autodidactic Master of Arcane and Hidden Knowledge.