Electrical Engineering - Transformers - Discussion

Standard Definition:

Turns Ratio K = N1/N2

N1 = Primary winding turns.
N2 = Secondary winding turns.

To calculate turn ratio, for step down transformer it should be N2/N1.

And for step-up transformer turn ratio should be N1/N2.

Turns ratio = voltage ratio.
N2/N1 = V2/V1.

Where,
V1 = 110.
V2 = 20.

Turns ratio = V2/V1.
= 20/110,
= 0.18.

Turns Ratio N1/N2, V1/V2.

Transformation Ratio (K) is inverse of Turns ration N2/N1, V2/V1.

@ALL.

Turns Ratio = Primary Quantity/Secondary Quantity. Denoted by 1/K. This is applicable to only applied voltage(V), number of turns(N) and induced emf(E). The reverse of this relation gives current turns ratio. i.e N1/N2=I2/I1.

Remember, Turn ratio for a transformer is - K'=1/K=N1/N2=V1/V2.
Where, K'=1/K is turned ratio of transformer and K= Transformation Ratio of Transformer
Transformation Ratio = Secondary Quantity/Primary Quantity=K only

In the given problem, V1=110V and V2=20V. This is correct because for a step-down transformer V1>V2 in relation with N1>N2 i.e No. of primary turns is always proportional to No. of primary voltage and vice versa.

Now, N1/N2=V1/V2=110/20=5.5 => N1/N2=5.5=K' where K'=Turns Ratio of Transformer. Hence Option A is correct. Note:- Please do not confuse with Turns Ratio (K') & Transformation Ratio (K).

It's is confusing that, somewhere we used the turn ratio as n1/n2=v1/v2 or somewhere n2/n1=v2/v1.

What is turns ratio formula? Please, can you help me?

n2/n1 is the transformation ratio.
n1/n2 is the turns ratio.
n1/n2 = v2/v1.

So, the answer is 0.1818.

I am confused please give me the correct answer.

Definition by IEEE.

It is the ratio of a number of turns in the high voltage winding to the number of turns in the low voltage winding.

It is always more than 1.

If you disagree then, Prove me.