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Re: Tingles from power supply

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Which I already mentioned as being one reason for switchers becoming more
prevalent now the cost differential is small.

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Which has what exactly to do with your claim "most are not switchers" and
"few are"? That is what I disputed, not some new load of total
irrelevancies.

But frankly I seriously doubt if you could tell if a handgun had one bullet
in the chamber or was empty anyway.
I'd really like to see you place it to your head, decide if it was empty,
and pull the trigger based on your guess :-)

Picking a switching power supply is childs play by comparison, but was never
in dispute.

MrT.



Re: Tingles from power supply

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  Why?  Because you THINK that shipping them would be that much greater?

  That difference is not offset enough by the difference in cost you
tout.

Re: Tingles from power supply

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What difference in cost?

MrT.



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  I would typically test such an unknown on a dope like you.

Re: Tingles from power supply

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bullet

I'm glad you now admit it's an unknown, just like the rest of your claim.

MrT.



Re: Tingles from power supply

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  There was no discussion on choosing power supplies.

Re: Tingles from power supply

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never

Exactly, you made an unsubstantiated claim, and I simply disputed it.
Provide some actual figures or move on.

MrT.



Re: Tingles from power supply



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Oh, they have to be filtered ( to meet EMC regs ) but may use some very simple
ones at very low powers since that's all that's needed.

Graham



Re: Tingles from power supply

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   I have never seen a transformer type wall wart with a filter; the
switchers are not so common and being newer kids on the block that tend
to generate EMC, would have some kind of filtering.

Re: Tingles from power supply



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simple
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Just a transformer type. No indeed.


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The switchers are becoming much more common now.

Graham



Re: Tingles from power supply

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 Yes.  Switchers are noisy, but I would venture that these small, barely
capable types are even worse than OEM open frame or off-the-shelf types.
They actually have a few design cycles in most of them.  These El Cheapo
mini-switchers are likely the biggest source of local noise around.

Re: Tingles from power supply



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You come to this conclusion how ? Measuring the weight for a given DC output
would easily sort that out.

Graham


Re: Tingles from power supply
On Wed, 11 Mar 2009 01:53:04 +0000, Eeyore

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 A simple glance at the output ripple waveform will also determine if it
is a switcher or not. D'oh!

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Good Lord ! You actually said something sensible for the first time I can recall.

The only snag is 'intercepting' the output conveniently to do such a thing.

Graham



Re: Tingles from power supply
On Wed, 11 Mar 2009 03:55:30 +0000, Eeyore

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recall.
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  You need an "oscilliceptor".

 There is no inconvenience in probing a simple DC plug's pins,
dingledorf.

 Bwuahahahahaha!

Re: Tingles from power supply

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   Transformers capacitively couple this "tingle" from input (primary)
AC voltage to the secondary.
   Determined by feel over the past 60 years.
   Has nothing to do with output being AC or DC or output voltage or load.
   ??weight???  Wuzzat??

Re: Tingles from power supply
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How much capacitance would there be between the primary and secondary of
  a lower power mains transformer?

Sylvia.

Re: Tingles from power supply
On Thu, 12 Mar 2009 17:23:13 +1100, Sylvia Else

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  Inter-winding capacitance varies from one transformer to another based
on the transformer construction and the winding placement, and the number
of tape layers (or paper) between the two windings.

Re: Tingles from power supply

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   My guess is between 10pF and 100pF; measure it on a "free"
transformer: between a primary wire and a secondary wire.

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Naturally since there will be inter-winding capacitance. I'd be surprised at
100uA
from probably no more than a 25 VA TX though.


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Determining if it's a line frequency TX or an SMPS.

If the label says 100-240V input ( or similar ) you can also be sure it's an
SMPS.

Graham



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