Electrical Engineering - Transformers - Discussion

Discussion Forum : Transformers - General Questions (Q.No. 11)
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?
9 V
90 V
900 V
0.9 V
Answer: Option
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.

Discussion:
24 comments Page 2 of 3.

Chandra said:   1 decade ago
I agree with @Ajeet.

Turns ratio = n1/n2 but not n2/n1 it is transformation ratio.

Therefore v1/v2 = n1/n2.

v1/0.9 = 9=>v1 = 0.9v.

Sivaranjan said:   1 decade ago
Turns ratio means N1/N2 not N2/N1. Thus it should be 0.9V. I am agreed with all above who got 0.9V.

SADDAM HUSSAIN said:   1 decade ago
Turn ratio is N1/N2= 0.1.

V2/V1 = N2/N1 = 10.

9/V1 = 10.
V1 = 9/10.
SO V1 = 0.9V.

Suda said:   1 decade ago
Can anybody explain turns ratio is either n2/n1 or n1/n2?

Knowledge said:   1 decade ago
Turns ratio = (Number of turns in the hv winding)/(Number of turns in the lv winding).

For step up transformer primary winding is lv winding and secondary winding is hv and vice-versa.

Knowledge said:   1 decade ago
Don't try to memorize it as n1/n2 or n2/n1....It may cause trouble. Get your basics right.

Adesh thakur said:   10 years ago
I am very confused what is the turn ratio & transformer ratio tell me.

Ram said:   9 years ago
Hey @Knowledge,

If Turns ratio = (Number of turns in the have winding) / (Number of turns in the lv winding).

Then how turns ratio = 0.1?

Amol said:   9 years ago
You are right @Ram.

The hv winding turns are always more than lv.

Amani naidu said:   9 years ago
Turns ratio = n1/n2.
Transformation ratio = n2/n1 .
So answer is 0.9v.
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