🚀 go-pugleaf

Eeyore wrote:

> Rich Grise wrote:
>
> > On Mon, 09 Mar 2009 01:20:22 +1100, 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?
> >
> > If the wart is 2-prong, turn it around in the socket. If it's 3-prong,
> > get an outlet tester.
>
> 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

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.