Question

A transformer with 700 turns on the primary coil is used to decrease the voltage from 1500 V to 120 V for home use. How many turns should be in the secondary coil? A) 11.2 turns B) 88.2 turns C) 116.666667 turns D) 56 turns E) 4.285714 turns

Answer 1

Correct answer: D) 56 turns

Step-by-step explanation:

In the ideal transformer it is assumed that: a) there is no power loss of any

kind; b) all the magnetic flux produced by the primary coil passes through the coil

high school. This implies that the power entering the primary is the same as

it goes on the secondary to a load that is connected.

Based on these concepts and analyzing the ideal transformer circuit, this relationship between voltages and number of turns of each coil can be reached:

• Vp/Vs = Np/Ns

Np: number of turns of the primary circuit coil.

Ns: number of turns of the secondary circuit coil.

Vp: primary circuit voltage.

Vs: secondary circuit voltage.

Therefore the number of turns of the secondary coil will be:

Ns= (Np/Vp)×Vs = (700 turns/1500V)×120V = 56 turns