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Re: Tingles from power supply
On Tue, 10 Mar 2009 05:19:55 -0700, FunkyPunk FieldEffectTrollsistor

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"Pretty simple shit" is what you constantly spout from your fetid gob.

Re: Tingles from power supply



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They also know what abuse and newsgroup charters are too. Not to mention
flooding.

Graham


Re: Tingles from power supply



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There is NOTHING illegal about giving a warning of a potential abuse report.

I have been in touch with Cox now to enquire if your behaviour contravenes
either their AUP or T&C.

Graham


Re: Tingles from power supply
On Tue, 10 Mar 2009 23:49:02 +0000, Eeyore

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either their AUP or T&C.
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  Yes, and as I said before, it doesn't matter.  You get filed in file
number 13 after you get the standard response from them, and no "flags"
get set on my account.  Not even so much as a check box.

 My life goes on.

 *If* I am approached about your stupidity, I will outline just who you
are, and within 3 minutes of reading my response, and looking at my
pointers, they will ignore any future horseshit you sling their way in
your sad attempts to attack me.

  Have fun, donkey brain.

Re: Tingles from power supply

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If the wart is 2-prong, turn it around in the socket. If it's 3-prong,
get an outlet tester.

Cheers!
Rich



Re: Tingles from power supply



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Sylvia's experience is 100% normal. I've even modelled it in the past which
is why I reckon the Y cap between the rectified pri and sec sides is 2n2.

I was myself at the time specifically interested in the value of the leakage
current and its waveform shape. It gives a great 'buzz' with lots of
harmonics in poorly grounded audio systems. The audio groups regularly get a
question why their laptop buzzes on the mains but not on battery power. About
once a month on average.

Cue EMC discussion ?

Graham


Re: Tingles from power supply



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I reckon whomsoever allowed a capacitor/resistor/whatever to straddle
a magnetically isolated, electrical safety barrier, ought to be
marched out of their keep-the-public-safe-committee office and shot.

Re: Tingles from power supply



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I could be tempted to agree.

Needless to say there's a reason for the method which as I said you'll find in
the
EXCELLLENT app notes at powerint.com. It surprised me too.

The transformer would have coupling capacitance anyway.

This one's a real little runner. It can make life very much more complicated.

BTW, try connecting a modern printer to your PC at night with low illumination.
Look out for the sparks.

Graham



Re: Tingles from power supply
On Tue, 10 Mar 2009 01:48:05 +0000, Eeyore

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   You're an idiot.

Re: Tingles from power supply


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leakage
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a
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About
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the
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That truly is an excellent site. I went to have a quick check to check
on this puzzle  and was there an hour. Will be returning.
After running through 20  <10Watts  reference design pdfs, it seems
95% of their wall wart type external supplies -do not- have that mains-
DC straddle capacitor. Go beyond 10Watts and the 'unsafe' capacitor
starts appearing, usually 2n2.
Then I had to start reading the other app' notes to see what you were
specifically pointing at.
Only relevant refs I came across were AN14, AN20, AN15.
AN14 makes a coy coment about the capacitor helping common mode
"emission currents" (WTF!).
AN20 "Transient suppression" has this capacitor wired as part of a 3
capacitor splitter. Seems  a bodge arrangement so that  a 3kV input
transient turns up at the 'safe' DC output as only 1.5kV!.
Only actual technical reference I found was AN15 (emc design).
Specifically Figure 33 and their transformer stray coupling item
marked "CW4". The straddle capacitor being added to "augment" that
particular stray.
So, based on the above notes, I'm reading that this capacitor is
purely there for the manufacturers benefit!. It is fitted to help kill
off the nasty HF noise that naturally couples across via C strays from
the transformer primary to secondary.
Essentially, the manufacturer generates the sodding switched mode
noise in the first place then has no alternative but to find some
method of filtering their rubbish out of the floating DC secondary.
Only means they have is the naff bridging capacitor, which results in
the leaking AC, the tingles and the sparks in the dark.
Ban the damned things, that's what I say :)
Ps. My wall wart that blew some kit up had a Varistor fitted instead
of that cap!.


Re: Tingles from power supply
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in the
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Note this one: (From an15.pdf)

"(2.1.10): Equipment shall be so designed that at an external
point of disconnection of the mains supply, there is no risk of
electric shock from stored charge on capacitors connected to the
mains circuit. Equipment shall be considered to comply if any
capacitor having a rated capacitance exceeding 0.1 uF and
connected to the external mains circuit, has a means of discharge
resulting in a time constant not exceeding 1 second for pluggable
equipment type A (non-industrial plugs and socket-outlets).
This requirement specifically applies to any EMI filter capacitor
connected directly across the AC mains which could cause a
shock hazard on the exposed prongs of an unplugged power
cord."

One could easily touch both pins of a supply plug within one second!

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This can become especially bad with mis-wired outlets!  Many internal
power supplies have RFI suppression capacitors wired between each line
and the chassis, which is supposed to be grounded through the "equipment
ground" in the US, or the equivalent in other countries.

--
Virg Wall, PE

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Not an Australian standard?



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IEC safety requirement. I think they state 2 seconds actually, so Power
Integrations were playing safe. Oz standards are based on IEC too.

Graham



Re: Tingles from power supply
On Tue, 10 Mar 2009 22:51:25 +0000, Eeyore

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 That's your problem...  what you think with.  Donkey brains have no
grasp of electronics.  Senile donkey brains are even worse still.

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I read the standard a couple of days ago and was quoting from memory.

Do YOU own any standards ?

Graham



Re: Tingles from power supply
On Wed, 11 Mar 2009 00:47:44 +0000, Eeyore

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  One does not OWn a standard, idiot.  One COMPLIES with standards and
guidelines.

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So you've never bought one. No surprise. Ever READ one ?

Graham


Re: Tingles from power supply
On Wed, 11 Mar 2009 01:45:44 +0000, Eeyore

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  One does NOT buy a standard either.  One buys a license to own a copy
of a standard, idiot.

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Yes you do. As in a physical copy.

You didn't reply to my question as to whether you'd ever READ a standard
btw.

Graham


Re: Tingles from power supply
On Wed, 11 Mar 2009 03:52:18 +0000, Eeyore

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 It was a stupid question, coming from an utterly stupid individual, and
did not, nor does not warrant an answer.

  You do NOT "buy a standard", idiot.

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