I use Nokia phones both in the US and in Europe. The European charger is specifically built for 220V. The US charger is limited to 110V. I have charged the Nokia in Europe by connecting the 110V charger to a 220 to 110 converter. That does not seem to overtax the converter. I would not use a plug adapter on the 220V charger and attempt to plug it into a 110V plug, nor would I used a plug adapter on the 110V and plug it into the 220V. In the latter case, I believe you will get a good deal of smoke and a ruined converter.

Tom