Power grid distribution systems use transformers with simple designs that use coil wounds around a magnetic core in various regions. These wire coils take incoming current and change the voltage according to the transformer turns ratio, which is a ratio of the number of turns in the transformer.Np/Ns = Vp/VsWhere,Vp = Primary voltage,Vs= Secondary voltage,Np = number of turns in the primaryNs  = number of turns in the secondaryThis transformer winding formula describes how a transformer changes incoming voltage by a fraction and how the voltage of a coil's winds is directly proportional to the number of coil windings.