ok guys its something thats been nagging me but i have not asked for a while... whats the difference between AAA and AA batteries? i mean is it just physical size or is there more to it?
Its Mostly all about the size. Greater volume in the battery means you pack more of the reactive chemicals into a single cell, giving Longer / Higher current draw.
Jase touch on it pretty good but there's a bit more.
While aa and aaa have the same voltage, no load, the aa's will output more current because they have lower internal resistance. This is why a couple of my red's have no resistor using aaa's. If I put in aa's ---- POOF --- behold a weak LED :-(.
When building RED's with DVD LD's, you need to "characterize" it and draw your series circuit including all resistances, voltage drops and cell impedances. Even then, there's a big GULP when you push the button. !!!