> (...) roughly 4mm of distance is required between the two circuits. (As I discuss in Tiny, cheap, dangerous: Inside a (fake) iPhone charger, cheap chargers to

> (...) roughly 4mm of distance is required between the two circuits. (As I discuss in Tiny, cheap, dangerous: Inside a (fake) iPhone charger, cheap chargers totally ignore these safety rules. Which is why I immediately destroy any charger at my home that is suspect to not come from a brand name producer. Is it really worth to risk your life for couple of dollars? Electronics is my hobby and I also happen to design some switch mode power supplies for AC. I can't overstate how difficult it is to design a good safe SMPS. Comparing to my other projects it seems it is at least 20-50 times harder to design a dedicated SMPS than the rest of the circuit, even with a lot of specialized literature on the matter to help me out (meaning I don't create my own topologies, I just learn the ones that are well described in the book). And that for applications under 100W.