For example, if the primary coil of a transformer has 100 turns and
the secondary has 200 turns,  Ns/Np = 2 and Np/Ns=1/2 Thus, a 220V
input at 10A will step-up to 440 V output at 5 0 A If the secondary coil has less turns than the primary (Ns < Np),
we have a step-down transformer