Ok, but...
Let's pretend for a moment that i come from a technical institute in high s=
chool, i studied Electrotechnics (i hope i spelled it right), but thanks to=
 our public school minister, if i was born five years ago i wouldn't have t=
his problem. I have NOT studied  power supply system, so I don't know WHY t=
his happens. I know that a lot of hum comes from switching power supplies (=
and since i come from italy, i think it has 220V hum ;) )... Because it wor=
ks basically like a pwm module.

Now what i can't understand is WHY only the pwm module doesn't work.... If =
it's so obvious that it's not written anywhere, i am sorry ;)

> From: bobblick@ftml.net
> To: piclist@mit.edu
> Subject: RE: [PIC]PIC18F2550A,	Pwm doesn't work when using on external po=
wer    supply
> Date: Tue, 27 Sep 2011 08:48:19 -0700
>=20
>=20
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> On Tuesday, September 27, 2011 5:16 PM, "Jacopo Monegato"  wrote:
> >=20
> > Yes, i was thinking about that. the 12 VDC is from a switching laptop
> > power supply. Using my sound card as an "oscilloscope" i see that there
> > is a LOT of hum in the ground signal, but i don't know how to remove it=
...
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> Laptop power supplies can have 100 VAC common mode hum. Yes, 100 volts.
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> Cheerful regards,
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> Bob
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