🚀 go-pugleaf

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