In The Compleat Enchanter (as in other such multiverses), when Harold Shea is transported to a world where some particular form of magic works, any technology he takes along with him becomes inoperative.
What if that's because Shea is a psychologist, and our world's technology is, to him, magic?
If, say, a metallurgist were transported to one of these magical worlds, would stainless steel work for him? Would matches work for a chemist?
Story possibilities! (OK, so maybe it's been done and I haven't encountered it.)
Hm. Engineering student at university, who's read enough sci-fi to know better, gets involved with eldritch redhead who turns out to be Shea's granddaughter... that idea's been floating around the back of my head for years, and this could add an interesting twist: tech transported across worlds works if and only if it's not magic to the person trying to use it. Could have implications for a wizard transported to our world: only the spells he truly understands are portable.
...Now I need to find time to re-read those stories and see if this notion fits....