This can not be measured with a multimeter well, plus there needs a Oszi because the interference in the MHz range or slightly below it and therefore are still load-dependent.
In addition to the noise emission comes with this device even an obviously high noise sensitivity (total loss) are added, as noted by many users here.
For me, the capacitive touch screen of the Nokia Lumia 800 failed completely, while it was connected to the Mumbi.
An inquiry at the mobile phone dealer if he has heard of this effect before, he only said that the failure of the mobile phone and the guarantee of the same was gone - Well fine!
CONCLUSION:
The mumbi USB charger I sent back by return mail.
The device fulfills clearly not the European EMC directive (electromagnetic compatibility).
For insensitive and inexpensive user terminals could take the risk of breakdown yet. But with a smart phone or the like, the potential damage of proportion is in order to save a few euros on the acquisition of a 5V power supply.
How do you now recognize a suitable device?
Apart from the original accessories or recommended by the manufacturer, the CE marking with information about the applied EMC Directive (EN 61000-6- ..) is an indication that the manufacturer was at least endeavor to respect the relevant EMC standards.
So keep your eyes and wallet on the purchase.
