An AC adapter for a telephone answering machine uses a transformer to reduce the

Question

An AC adapter for a telephone answering machine uses a transformer to reduce the line voltage of 120 V to a voltage of 5.00 V. The RMS current delivered to the answering machine is 570 mA. If the primary (input) coil of the transformer has 480 turns, then how many turns are there on the secondary (output) coil?

What is the power drawn from the electric outlet, if the transformer is assumed to be ideal?

What is the power drawn by the transformer, if 19.5 percent of the input power is dissipated as heat in the coils and in the iron core of the transformer?

I know the first part is 20 turns. And I know the last part is (1-.195)x=part two.
I can't figure out part 2!

Explanation / Answer

(Ep / Es) = (Np / Ns) = (Is / Ip) Ep / Es = 120 v / 9 v = 14.444 Np / Ns = 240 / X = 14.444, solve for X Is / Ip = 0.400 / Ip = 14.444, solve for Ip secondary power = Is x Es = 0.400 x 9 = 3.6 Watt primary power = Ip x Ep = Ip x 120 = 3.6 Watt, solve for Ip Transformer operating power will be the same for both the primary and the secondary windings, only the current and voltage will be different. In a voltage step down transformer, voltage is stepped down but current is stepped up in exact

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.