In this example we will see how a transform can be used to change the voltage ou

Question

In this example we will see how a transform can be used to change the voltage output of a wall receptacle. A friend returns from Europe with a device that she claims to be the world's greatest coffee maker. Unfortunately, it was designed to operate from 240 V line, standard in Europe. At this rms voltage, the coffee draws 1260 W of power. (a)if your friend wants to operate the coffee maker in the United States, where the rms line voltage is 120 V. what turns ratio does her transformer need to have for the coffee maker to work? (b) What current will the coffee maker draw from the 120 V line? (c) What is the coffee maker's resistance? (These voltage and currents are rms values so the power quantities are given by V_1I_1= V_2I_2.) Suppose we want to use the coffee maker on an airplane on which voltage is 100 V. find the terms ratio of the required transformer: Express your answer as a fraction. Find the ratio R' of primary voltage to current for the coffee maker on the airplane. Express your answer in ohms to two significant figures.

Explanation / Answer

A) N2/N1 = V2/V1 = 120/240 = 1/2

N2 = N1/2

N2/N1 = 1/2

B) P = V*I

current I = P/V = 1260/120 = 10.5 A

C) R = V/I = 120/10.5 = 11.42 ohm

Part A) N2/N1 = V2/V1 = 600/240 = 5/2

N2 = 5N1/2

Part B)

current I = P/V= 1260/600 = 2.1 A

R = V/I = 600/2.1 = 285.71 ohm

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

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