Hi mbrueckm
I have spoken to our Head of Electronics and he has informed me that the Pico is powered from the USB line - it contains no internal power source i.e. battery. It does however generate some other power supplies internally, but none of these are greater than 6V, which is too low to cause an electric shock, and is not considered to be a hazardous voltage.
The metal case of the Pico has a direct electrical connection to the 'ground' signal of the USB cable, which is probably in-turn connected to the case of your computer (and therefore possibly to mains Earth, depending on the power supply arrangement of your computer).
He suggested that one of two likely things is happening :
1) The shock is a static shock, and the Pico is acting as the discharge path to ground for a static charge that has built up within your body.
Static shocks are extreemly common in some environments, and become worse the drier the air is. The body can easily get charged up by, for example walking across a carpet and will discharge to the first available path to ground.
If the cause of the shocks is static, then you should also be experiencing similar shocks sometimes when you touch other earthed metal objects.
2) The source of the shock is actually voltages present on the case and/or earth of your computer, and are being transmitted to the case of the Pico via the 'ground' signal of the USB cable.
If you suspect that this is the case, then we would strongly recommend that you have your computer tested by a professional electrician, as you may have hazardous mains voltage present on the case.
I would suggest trying the Pico with another computer if you have access to one (e.g. a lap-top running off battery, with no mains connection). Assuming you do not continue to get shocks off the Pico, then this should eliminate the Pico itself as the source of the shocks.
If the computer is the source of the shocks, then you would probably receive similar shocks when touching bare metal parts of the computer case, or by touching a USB connector metal outer shell (with the cable plugged into the computer, but with the Pico not connected). ** However we would not suggest trying this test, if you are at all suspicious that the computer earth/case may have a hazadous voltage on it **
Mains voltage electric shocks can be deadly in the wrong circumstances, so we would urge caution if this appears to be a possible cause of the shocks.
I am assuming from your description that the Pico is still operating correctly. It is very hard to imagine an internal fault that could generate an electric shock, especially if the instrument is still working.
I hope that helps, if you have any more questions or concerns please do not hesitate to contact me.
Regards
Aaron
Customer Services
UK
