Electrical Engineering - Transformers

Exercise :: Transformers - General Questions

11. 

How many primary volts must be applied to a transformer with a turns ratio of 0.1 to obtain a secondary voltage of 9 V?

A. 9 V
B. 90 V
C. 900 V
D. 0.9 V

Answer: Option B

Explanation:

We know that, V2/V1 = N2/N1.

Given V2 = 9v, N2/N1 = 0.1

Therefore, 9v/V1 = 0.1

V1 = 9v/0.1 = 90v.

For more detail: Step Down Transformer - Circuit with Simulation.


12. 

In a certain loaded transformer, the secondary voltage is one-fourth the primary voltage. The secondary current is

A. one-fourth the primary current
B. four times the primary current
C. equal to the primary current
D. one-fourth the primary current and equal to the primary current

Answer: Option B

Explanation:

No answer description available for this question. Let us discuss.

13. 

A certain transformer has a turns ratio of 1 and a 0.85 coefficient of coupling. When 2 V ac is applied to the primary, the secondary voltage is

A. 1.7 V
B. 0.85 V
C. 1 V
D. 0 V

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.

14. 

The primary coil of a transformer is connected to a 60 V ac source. The secondary coil is connected to a 330 load. The turns ratio is 3:1. What is the secondary voltage?

A. 2 V
B. 20 V
C. 180 V
D. 18 V

Answer: Option B

Explanation:

No answer description available for this question. Let us discuss.

15. 

The primary winding of a power transformer should always be

A. open
B. shorted
C. switched
D. fused

Answer: Option D

Explanation:

No answer description available for this question. Let us discuss.