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My Arduino Uno R3 gives me an electric shock upon touching one of its pins when my legs are on the ground.

The shock is not that trivial since if the pin is related to some LED the LED lights up which means that this at least 5mA of current or so. And of course is not from its 5V outputs.

The Arduino is powered from USB-2 from my computer and even the ground pin gives this shock.

I guess this has to do with my computer power supply it's a Hector 350W with two pins without an earth onnection.

Is there a way to just get rid of this annoying shocks?

I am not that expert with electricity but I am not a beginner either so I think I can handle it if someone just pointed me to where I can start searching or something.

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  • \$\begingroup\$ Can you take a picture of the power supply input? Is that a laptop? I don't see why would a desktop PC have a two-prong mains input. If it does have 3-prong mains input, it must be connected to 3-prong outlet, or you will get shocks and connecting equipment together must be done with unplugged socket to avoid damage when connecting devices. Two-prong inputs also can have common-mode filter capacitor between mains and output. \$\endgroup\$
    – Justme
    Commented Oct 3, 2020 at 17:45
  • \$\begingroup\$ @Justme Nope It just has Two input pins not all countries have 3 input pins It is just like this one: google.com/… \$\endgroup\$
    – Mahmoud Salah
    Commented Oct 4, 2020 at 19:03
  • \$\begingroup\$ That's an European grounded plug. It is grounded. What do you mean by this? \$\endgroup\$
    – Justme
    Commented Oct 4, 2020 at 19:28
  • \$\begingroup\$ @Justme I don't really understand your question..!! What I mean by this ? \$\endgroup\$
    – Mahmoud Salah
    Commented Oct 4, 2020 at 23:11
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    \$\begingroup\$ Well, perhaps you have an ungrounded wall socket? Post a picture of that. But the laptop plug is grounded plug based on what you posted. And grounded plugs must be connected to matching grounded wall sockets. Whether you see ground rods around your house may be irrelevant here, the mains ground might come via a cable from electric company like phases and neutral do. \$\endgroup\$
    – Justme
    Commented Oct 5, 2020 at 18:10

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The power supply of your PC has a mains filter. That one has some capacitors between both mains poles and the grounding. The mains ground is also tied to the case of your computer through capacitors and that one to the ground pin of USB.

All the "grounded" parts are at half of the mains voltage unless the grounding of the building you are working in is superb. I have not yet encountered such a building.

The current is however sure less than one milliampere. LEDs light up from a few microamperes already, just not very brightly.

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    \$\begingroup\$ That only applies if the power supply has 3-prong input which requires to be connected to earthed socket for the mains input filter to work properly. If the computer supply only has 2-prong input, it must not have the ground-requiring filter. \$\endgroup\$
    – Justme
    Commented Oct 3, 2020 at 17:50

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