1. The problem statement, all variables and given/known data 2. Relevant equations Fourier and then V(output) = 4Vs/(n*3.14) * sin (nwt) where Vs is battery here it's 400V Current = V(output) / X(L). Here X is 2*3.14*100*0.2 3. The attempt at a solution I got V(output) = 4*400/3.14 = 509.55V This is fundamental Peak output voltage. So Current peak = 509.55 / impedance. Impedance = 2*3.14*100*0.2 = 125.6 Ohm So Current peak = 509.55 / 125.6 = 4.06A But this is not in option. If i use other method of V = L di/dt Here for time interval by green line 400 = 0.2 * di/dt dt = time interval in green part = time period / 4. Frequency = 100 Hz. So Time period = 0.01 seconds So dt = T/4 = 2.5 milli seconds So 400 = 0.2 * di / dt This gives di = 5 A. But why don't i get correct answer if I go by above method of fourier?