ExamAdept

To step 110 V ac down to 20 V ac, the turns ratio must be

A:

5.5

B:

18

C:

0.18

D:

0.018

Answer: C

Vp/Vs = Np/Ns

Vs = (Ns/Np)Vp

We required turns ratio i.e., (Ns/Np)

= Vs/Vp

= 20/110

= 0.181818182

[Note: p - primary; s - secondary]

For step down transfer, the turns ratio will be less than 1.

For simulation: Step-Down Transformer Circuit Simulator.

📖

The primary winding of a transformer has 110 V ac across it. What is the secondary voltage if the turns ratio is 8?

A:

8.8 V

B:

88 V

C:

880 V

D:

8,800 V

Answer: C

V2/V1 = N2/N1

Turns ratio = N2/N1 = 8.

V2/110 = 8

V2 = 8 x 110

V2 = 880v.

📖

A certain transformer has 400 turns in the primary winding and 2,000 turns in the secondary winding. The turns ratio is

A:

0.2

B:

0.4

C:

5

D:

25

Answer: C

No answer description is available. Let's discuss.

📖

If a transformer has 50 turns in the primary winding and 10 turns in the secondary winding, what is the reflective resistance if the secondary load resistance is 250

?

A:

250

B:

25

C:

6,250

D:

62,500

Answer: C

No answer description is available. Let's discuss.

📖

When the turns ratio of a transformer is 20 and the primary ac voltage is 12 V, the secondary voltage is

A:

12 V

B:

120 V

C:

240 V

D:

2,400 V

Answer: C

No answer description is available. Let's discuss.

📖

Questions for: Transformers