Question

Question 11 The rechargeable batteries for a laptop computer need a much smaller voltage than what a wall socket provides. Therefore, a transformer is plugged into the wall socket and produces the necessary voltage for charging the batteries. The batteries are rated at 9.0V, and a current of 237 mA is used to charge them. The wall socket provides a voltage of 120 V.(a) Determine the turns ratio of the transformer. (b) What is the current coming from the wall socket? (c) Find the average power delivered by the wall socket and the average power sent to the batteries (a) N/N, Number Units (b) lp Number Units (c) Pp Number Units P Number Units Attempts: 0 of 4 used

Answer 1

a) N_s / N_p = V_s / V_p = 9 / 120 = 0.075

b) I_p / I_s = V_s / V_p

Ip = V_s / V_p * I_s = 0.075 * 237 mA = 17.77 mA

c) P_p = V_p * I_p = 120 * 17.77 * 10^-3= 2.13 W

P_s = V_s * I_s = 9 * 237 * 10^-3= 2.13 W