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?
"Mike B"
** Is that a battery operated laptop ?but has a 50Hz noise problem when connected to a normal desktop PC.
** Grounding usually fixes noise injection.** Don't be coy - what do you call " research " ???
** The earth could be flat too.
** Not unless you believe the earth IS flat. ** 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
F*CK the HELL OFF !!
..... Phil
I'm taking you off my Christmas card list.
Mike
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do you get the same problem if you ground the laptop? if not, it's not an earthing problem, it's something else.
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The noise increases by a factor of 4.
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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
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It seems your capacitor is acting like an antenna,
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