A step-down transformer operates on a 2200 V line and steps it down to 220 V. It supplies a load cur

Question

A step-down transformer operates on a 2200 V line and steps it down to 220 V. It supplies a load current of 5 A. Assuming 100% efficiency, the ratio of the secondary to primary windings ($N_s:N_p$) and the primary current are, respectively

Professor PC Thomas Classes · Answer

(b) : The voltage ratio defines the turns ratio: $N_s/N_p = V_s/V_p = 220/2200 = 1/10$, meaning the ratio is 1:10. Since efficiency is 100%, $V_p I_p = V_s I_s$, which means $I_p = I_s (V_s/V_p) = 5 	imes (1/10) = 0.5$ A.