Mike B
Guest
Mon Jun 27, 2011 12:32 pm
I'm using a USB connected capacitive sensor which works fine when connected to a
laptop, but has a 50Hz noise problem when connected to a normal desktop PC.
Research indicates this could be due to the USB ground being connected to the
mains earth inside the PC.
Earth isolation seems like an obvious solution, but I haven't been able to find
a class 2 power supply. Do they exist?
Mike
Dennis
Guest
Mon Jun 27, 2011 12:45 pm
"Mike B" <someone_at_noplace> wrote in message
news:n6tg07hl0l4laslq2dce98ilto04o47amj_at_4ax.com...
Quote:
I'm using a USB connected capacitive sensor which works fine when
connected to a
laptop, but has a 50Hz noise problem when connected to a normal desktop
PC.
Research indicates this could be due to the USB ground being connected to
the
mains earth inside the PC.
Earth isolation seems like an obvious solution, but I haven't been able to
find
a class 2 power supply. Do they exist?
Mike
USB isolator?
http://hackaday.com/2009/09/18/usb-isolation/
http://www.blackbox.com/Store/Detail.aspx/SP386A?CAWELAID=765203210
Phil Allison
Guest
Mon Jun 27, 2011 1:33 pm
"Mike B"
Quote:
I'm using a USB connected capacitive sensor which works fine when
connected to a
laptop,
** Is that a battery operated laptop ?
but has a 50Hz noise problem when connected to a normal desktop PC.
** Grounding usually fixes noise injection.
Quote:
Research indicates ...
** Don't be coy - what do you call " research " ???
Quote:
this could be due to the USB ground being connected to the
mains earth inside the PC.
** The earth could be flat too.
Quote:
Earth isolation seems like an obvious solution,
** Not unless you believe the earth IS flat.
Quote:
but I haven't been able to find
a class 2 power supply. Do they exist?
** No.
FFS - tell us what the heck you are trying to do and with what.
And if doing that simple thing is just not possible - then
FUCK the HELL OFF !!
...... Phil
Mike B
Guest
Mon Jun 27, 2011 2:30 pm
On Mon, 27 Jun 2011 23:33:28 +1000, "Phil Allison" <phil_a_at_tpg.com.au> wrote:
Quote:
FUCK the HELL OFF !!
I'm taking you off my Christmas card list.
Mike
Phil Allison
Guest
Mon Jun 27, 2011 2:38 pm
"Mike Bullshit is a Cunt "
Quote:
I'm using a USB connected capacitive sensor which works fine when
connected to a laptop,
** Is that a battery operated laptop ?
but has a 50Hz noise problem when connected to a normal desktop PC.
** Grounding usually fixes noise injection.
Quote:
Research indicates ...
** Don't be coy - what do you call " research " ???
Quote:
this could be due to the USB ground being connected to the
mains earth inside the PC.
** The earth could be flat too.
Quote:
Earth isolation seems like an obvious solution,
** Not unless you believe the earth IS flat.
Quote:
but I haven't been able to find
a class 2 power supply. Do they exist?
** No.
FFS DICKHEAD - tell us what the heck you are trying to do and with WHAT
!!
If doing that simple thing is just not possible - then
FUCK the HELL OFF !!
You BULLSHITTING PITA CUNT
...... Phil
Jasen Betts
Guest
Tue Jun 28, 2011 9:14 am
On 2011-06-27, Mike B <someone_at_noplace> wrote:
Quote:
I'm using a USB connected capacitive sensor which works fine when connected to a
laptop, but has a 50Hz noise problem when connected to a normal desktop PC.
Research indicates this could be due to the USB ground being connected to the
mains earth inside the PC.
Earth isolation seems like an obvious solution, but I haven't been able to find
a class 2 power supply. Do they exist?
Mike
do you get the same problem if you ground the laptop? if not, it's
not an earthing problem, it's something else.
--
⚂⚃ 100% natural
--- Posted via
news://freenews.netfront.net/ - Complaints to news_at_netfront.net ---
Mike B
Guest
Wed Jun 29, 2011 8:12 am
On 28 Jun 2011 09:14:38 GMT, Jasen Betts <jasen_at_xnet.co.nz> wrote:
Quote:
On 2011-06-27, Mike B <someone_at_noplace> wrote:
I'm using a USB connected capacitive sensor which works fine when connected to a
laptop, but has a 50Hz noise problem when connected to a normal desktop PC.
Research indicates this could be due to the USB ground being connected to the
mains earth inside the PC.
Earth isolation seems like an obvious solution, but I haven't been able to find
a class 2 power supply. Do they exist?
Mike
do you get the same problem if you ground the laptop? if not, it's
not an earthing problem, it's something else.
The noise increases by a factor of 4.
atec77
Guest
Wed Jun 29, 2011 8:47 am
On 29/06/2011 6:12 PM, Mike B wrote:
Quote:
On 28 Jun 2011 09:14:38 GMT, Jasen Betts<jasen_at_xnet.co.nz> wrote:
On 2011-06-27, Mike B<someone_at_noplace> wrote:
I'm using a USB connected capacitive sensor which works fine when connected to a
laptop, but has a 50Hz noise problem when connected to a normal desktop PC.
Research indicates this could be due to the USB ground being connected to the
mains earth inside the PC.
Earth isolation seems like an obvious solution, but I haven't been able to find
a class 2 power supply. Do they exist?
Mike
do you get the same problem if you ground the laptop? if not, it's
not an earthing problem, it's something else.
The noise increases by a factor of 4.
Sounds like you need to try another power point and another power supply
, switch mode supplys can be very noisy at times if there is an earthing
problem or a conflict with another switch mode on the same phase
--
X-No-Archive: Yes
Jasen Betts
Guest
Wed Jun 29, 2011 11:18 am
On 2011-06-29, Mike B <someone_at_noplace> wrote:
Quote:
On 28 Jun 2011 09:14:38 GMT, Jasen Betts <jasen_at_xnet.co.nz> wrote:
On 2011-06-27, Mike B <someone_at_noplace> wrote:
I'm using a USB connected capacitive sensor which works fine when connected to a
laptop, but has a 50Hz noise problem when connected to a normal desktop PC.
Research indicates this could be due to the USB ground being connected to the
mains earth inside the PC.
Earth isolation seems like an obvious solution, but I haven't been able to find
a class 2 power supply. Do they exist?
Mike
do you get the same problem if you ground the laptop? if not, it's
not an earthing problem, it's something else.
The noise increases by a factor of 4.
It seems your capacitor is acting like an antenna,
--
⚂⚃ 100% natural
--- Posted via
news://freenews.netfront.net/ - Complaints to news_at_netfront.net ---
no one
Guest
Sun Jul 10, 2011 11:07 am
"Phil Allison" <phil_a_at_tpg.com.au> wrote in message
news:96rf5hF1l6U1_at_mid.individual.net...
Quote:
"Mike B"
I'm using a USB connected capacitive sensor which works fine when
connected to a
laptop,
** Is that a battery operated laptop ?
but has a 50Hz noise problem when connected to a normal desktop PC.
** Grounding usually fixes noise injection.
Research indicates ...
** Don't be coy - what do you call " research " ???
this could be due to the USB ground being connected to the
mains earth inside the PC.
** The earth could be flat too.
Earth isolation seems like an obvious solution,
** Not unless you believe the earth IS flat.
but I haven't been able to find
a class 2 power supply. Do they exist?
** No.
FFS - tell us what the heck you are trying to do and with what.
And if doing that simple thing is just not possible - then
FUCK the HELL OFF !!
..... Phil
