septillion:
There are not that many countries left with a nominal 220VAC. Sure it's not 230VAC?But that cap should go on the output of the converter aka on the 5VDC side. A 10V 1000uF should be fine. And for safety, use a old (but preferably from a good brand) USB charger. Saves the hassle and is safe
Yes, I am sure of it. Everytime I think it is done, you add something new :D. And I don't want to bother you anymore, you have been very helpful, honestly. So, last question, at least I hope. Where will I use an usb charger? I mean once I program the arduino, usb will not be used ever again as long as, something goes wrong and I need to program the arduino again.