Re: Tingles from power supply

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#1529

From: FunkyPunk FieldEffectTrollsistor
Date: Sun, 08 Mar 2009 21:57

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On Sun, 08 Mar 2009 19:40:02 +0000, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

>
>
>Sylvia Else wrote:
>
>> Sylvia Else wrote:
>> > I've recently bought a D-Link DIR-300 wireless router. While
>> > disconnecting its power supply from it, I got a tingling sensation when
>> > I touched the plug (to be clear, I'm talking about the 5V DC plug, not
>> > the mains plug).
>> >
>> > An AVO meter shows about 90V AC to earth from either side of the 5V
>> > plug. Short circuit current to earth is about 0.1mA.
>> >
>> > Still, I thought these things were meant to be completely isolated. Has
>> > there been a change of approach?
>>
>> Apparently it's normal, and is related to RFI suppression.
>
>100% correct. It'll almost certainly be a Y2 cap between the live and
>secondary sides of the switching transformer.

  Switcher front ends have transformers?  Are you mixing your power
supply designs in your head, boy?

>Go to powerint.com to find out why it's there.

  Do the math on the cap and find out that even "fully charged" it will
not present the scenario she described.  You are all fucking loony tunes
if you think it does.

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From: FunkyPunk FieldEffectTrollsistor <FunkShunPoignter@yermomma.org>
Newsgroups: sci.electronics.design,aus.electronics
Subject: Re: Tingles from power supply
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