Rasmus Keis Neerbek

Thank you very much, that was really helpfull. Rasmus

Simple school project: We're looking at a model of a generator. We have an iron core, spools of cobber wire and a rotating magnet. First we just test how much voltage is generated using different spools with different amount of coils - more coils equals higher voltage. Now we test which setup are most efficient in making a small bulb glow. It turns out, that 400 coils are more efficient than both 200 and 1600 coils. Reason of course, because the spools are of same size, so the diameter of the copper wire is different, and 1600 coils gives a very thin wire with high resistance. Person A claims, that the thin copper wire is also longer, and that will naturally increase the resistance also (although the diameter is the most significant factor) Person B claims, that the length in the copper wire has no effect in this case, because the rotating magnet gives an alternating current, and therefore it is only the diameter that counts (if we had a direct current things would be different) Who is right? Rasmus (hope its clear - english is not my first language)