As an engineer, you should appreciate the details...
http://www.arcfn.com/2012/05/apple-iphone-charger-teardown-quality.html
I remember packing a RS 220/120 converter to Greece in '79 to run things, it blew a fuse, so I went to an electronics shop, all they could offer was a monster transformer... I used a paperclip to bypass the fuse, still in it, I bet.. Lesson: Don't use a 120 vac converter to run a hair dryer to dry socks!