What is the function of a step up transformer.

step up transformers is used to step up or increase the voltage which is done by secondry coil i.e the secondary has more no. of turns as when compared to primary coil (NsNp) so wen a (v) amount of voltage is given to a primary coil it induces a mag field were there is secondary coil which gets disturbed due to the mag field of primary so there is a induction of current in secondry coil but the induced current here is very large due to more no of turns so the voltage compared in sec coil is more. therefore it acts as step up transformers. :D