A step-down transformer is used for recharging the batteries of portable electronic devices. The turns ratio N₂/N₁ for a particular transformer used in a DVD player is 1:10. When used with 120-V (rms) household service, the transformer draws an rms current of 27.0 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 94.0%, but the power delivered to the Blu-ray player remains the same? mA

The primary coil of a transformer has N₁ = 320 turns, and the secondary coil has N₂ = 2 190 turns. If the input voltage across the primary coil is Av(t) = 170 cos wt, where Av is in volts and t is in seconds, what rms voltage is developed across the secondary coil? V

A transformer is to be used to provide power for a computer disk drive that needs 5.6 V (rms) instead of the 120 V (rms) from the wall outlet. The number of turns in the primary is 420, and it delivers 500 mA (the secondary current) at an output voltage of 5.6 V (rms). (a) Should the transformer have more turns in the secondary compared to the primary, or fewer turns? O There should be more turns in the secondary. O There should be fewer turns in the secondary. (b) Find the current in the primary. (c) Find the number of turns in the secondary. turns

A typical wall outlet voltage in the United States is 120 volts. Personal MP3 players require much smaller voltages, typically 104.2 mV. If the number of turns in the primary coil is 6908, calculate the number of turns Ng on the secondary coil of the adapter transformer. Ns turns