Can an efficient transformer step up energy?
A transformer is used to change the voltage in an electric circuit. The power that enters the transformer is P(entrance)U(e)i(e) (1) the power that leaves it being P(exit)u(exit)I(exit) In general P(exit)P(entrance) and you can define the efficiency of the transformer as [P(entrance)-P(exit)]/P(entrance). Is that what you wanted to know.
Yeah, they can do both, but has nothing to do with efficient. If you're asking if they can efficiently do it, that's in the eye of the beholder. In my eyes they can't. Oh, and when you are saying energy I suspect you mean voltage?
