Question

MS TOUR TEACHER A step-down transformer is used for recharging the batteries of portable electronic devices. The turns ratio N/N, for a particular transformer used in a DVD player is 1:15. When used with 120-V (rms) household service, the transformer draws an mms current of 23.5 mA from the house outlet (a) Find the rms output voltage (in V) of the transformer V (b) Find the power in W) delivered to the DVD player w (c) What If? What would be the current (in mA) drawn from the house outlet if the transformer had an efficiency of 86.0%, but the power delivered to the Blu-ray player remains the same? MA

Answer 1

ransformer 9. In case of step-down step-down trans a) the input and output voltage of of a Fransformed ideal is ocla fed Co the of turns by number out N out vin Nin > vout Nout in Hin furns ratio N2 ㅗ Here, given that voltage vin = 12000 15- Vout N2 Na X I X 120v 15 out 8V oms output voltage of transformer is usu" b) By Low conservation of Input power b of energy output power > in I in = rout. I out I vin. I in out Vout and Vin N in Yout out >. I out х л. im Nout 15 x 23.5ma - 352.5mA Fout = 0.3525A

output power Vout X I out 8Vxo 352SA Р 2:82w And Given that that toomformes. Efficiency is 86-1. Pe 0.86P Pi Pc 요 2.82 = 3.279w 0.86 0.86 and P;='v, I =) I, P, 3.279 w 12ou Ii = 0.02 732 A cuɣrent drawn Il = 27.325. MA Ang