Electrical Engineering - Transformers - Discussion

Discussion Forum : Transformers - General Questions (Q.No. 11)

Transformers

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.

Discussion:

24 comments Page 1 of 3.

Parashkthi.P.R said: 1 decade ago

E2/E1=N2/N1
N2/N1=0.1
E2=9
E1=9/0.1=90V

Chandresh Soni said: 1 decade ago

I agree with Parashkthi

Farah said: 1 decade ago

But turn ratio Np/Ns=0.1

Then,

Vp/Vs=Np/Ns
Vp/9=0.1
Vp=9

Is it correct?

Yogesh sabota said: 1 decade ago

I agree with farah this is incorrect
turn ratio=n1/n2=1/10
therefore
v1=0.9v

Himanish said: 1 decade ago

I agree with Yogesh
Turns Ratio is N1/N2=0.1
Therefore V1=(N1/N2)*V2

We get 0.9V

Always n1/n2=Turns Ratio

Siri said: 1 decade ago

Turns ratio=N2/N1 not N1/N2.

Ravindra rawat said: 1 decade ago

We know that,

k = v2/v1 = n2/n1.

n2/n1 = 0.9.

v2 = 9v.

v1 = 9/0.9 = 90v answer.

Ankur said: 1 decade ago

I think voltage is proportional to current means v1/v2 = n1/n2.

By this we will get 0.9 answer.

Eng/Attiya said: 1 decade ago

The turns ratio is under 1 so this is step up transformer meaning that Vp should less than Vs.

Ajeet chaubey said: 1 decade ago

Turns ratio(T.R) = N1/N2 = V1/V2 = I2/I1.

And,
Transformation ratio = 1/T.R.

Here,
T.R. is given,
So N1/N2 = 0.1=V1/V2, => V1 = 0.1*9 = 0.9.

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