Magnesium alloy going rogue - Electricity and vibrations
First off: Don't worry, this is not dangerous.
Yes, it's a pretty common effect on many unearthed power supplies. This will also happen with many cell phone chargers, especially powerful multi-port ones (5 port USB chargers, etc.).
Power supplies today are switch-mode power supplies, which means they convert the mains AC to DC, convert this DC back to a high frequency AC and feed it into a smaller transformer (because of the higher frequency). This is not the full story (search for "flyback", "smps design", etc.)
These supplies have a (very) small amount of AC leakage current flowing from the mains to the output.
Often there's a capacitor between the primary and secondary coil to reduce electromagnetic interference due to the high frequency switching.
This capacitor will leak a bit of current (max. 100µA). There is also capacitive coupling between the transformer windings, depending on how the transformer is wound.
In conclusion:
It's not dangerous, but a bit annoying.
You could use a different power supply (like one of the very high quality Lenovo USB-C laptop chargers, make sure to get one with earthing/3 pin plug!).
You could also plug another earth-referenced connection into the Pinebook, like an earthed monitor, earthed powered speakers, earthed powered USB hub, etc.
So long,
Tobias
Yes, it's a pretty common effect on many unearthed power supplies. This will also happen with many cell phone chargers, especially powerful multi-port ones (5 port USB chargers, etc.).
Power supplies today are switch-mode power supplies, which means they convert the mains AC to DC, convert this DC back to a high frequency AC and feed it into a smaller transformer (because of the higher frequency). This is not the full story (search for "flyback", "smps design", etc.)
These supplies have a (very) small amount of AC leakage current flowing from the mains to the output.
Often there's a capacitor between the primary and secondary coil to reduce electromagnetic interference due to the high frequency switching.
This capacitor will leak a bit of current (max. 100µA). There is also capacitive coupling between the transformer windings, depending on how the transformer is wound.
In conclusion:
It's not dangerous, but a bit annoying.
You could use a different power supply (like one of the very high quality Lenovo USB-C laptop chargers, make sure to get one with earthing/3 pin plug!).
You could also plug another earth-referenced connection into the Pinebook, like an earthed monitor, earthed powered speakers, earthed powered USB hub, etc.
So long,
Tobias