1. The problem statement, all variables and given/known data A transformer has a turns ratio of 5 : 1. It is connected to a 230 V supply and an output (secondary) current of 2.7 A is measured. If the transformer is 90% efficient, calculate: Secondary voltage Input (primary) current 2. Relevant equations Pout/Pin*100=efficiency 3. The attempt at a solution I dont think it can be solved as most of the equations dealing with transformers assume an ideal transformer.