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.

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.

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

Parashkthi.P.R said:   1 decade ago
E2/E1=N2/N1
N2/N1=0.1
E2=9
E1=9/0.1=90V

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.

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.

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.

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.

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.

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.

Siri said:   1 decade ago
Turns ratio=N2/N1 not N1/N2.


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