A step-up transformer is connected to an AC mains supply of 200 V to operate a device at 4000 V, 60

Question

A step-up transformer is connected to an AC mains supply of 200 V to operate a device at 4000 V, 60 W. Ignoring power losses in the transformer, the current in the primary circuit is

Professor PC Thomas Classes · Answer

(c) : Assuming an ideal transformer (zero power loss), the input power equals the output power ($P_p = P_s$). We are given the output power $P_s = 60$ W and the primary voltage $V_p = 200$ V. Using the power formula $P_p = V_p I_p$, we find the primary current $I_p = P_p / V_p = 60 / 200 = 0.3$ A.