Class 2 or double insulated computer ATX power supplies - d

[Mike B]

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]

"Mike B" <someone@noplace> wrote in message
news:n6tg07hl0l4laslq2dce98ilto04o47amj@4ax.com...

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]

"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

 

[Mike B]

On Mon, 27 Jun 2011 23:33:28 +1000, "Phil Allison" <phil_a@tpg.com.au> wrote:

FUCK the HELL OFF !!

I'm taking you off my Christmas card list.


Mike

 

[Phil Allison]

"Mike Bullshit is a Cunt "

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 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]

On 2011-06-27, Mike B <someone@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.


--
⚂⚃ 100% natural

--- Posted via news://freenews.netfront.net/ - Complaints to news@netfront.net ---

 

[Mike B]

On 28 Jun 2011 09:14:38 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2011-06-27, Mike B <someone@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]

On 29/06/2011 6:12 PM, Mike B wrote:

On 28 Jun 2011 09:14:38 GMT, Jasen Betts<jasen@xnet.co.nz> wrote:

On 2011-06-27, Mike B<someone@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]

On 2011-06-29, Mike B <someone@noplace> wrote:

On 28 Jun 2011 09:14:38 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2011-06-27, Mike B <someone@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@netfront.net ---

 

[no one]

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:96rf5hF1l6U1@mid.individual.net...

"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