# impedance ratio and transformers

#### dumindu89

Joined Oct 28, 2010
113
I need to know the relationship between the impedance ratio and the number turns of primary winding and the secondary winding of a transformer.

For an example if we take a transformer which has an impedance ratio of 1:13 what will be the number of turns of the primary winding and secondary winding?

Then, what would be the case if it is a center tapped transformer?

#### bertus

Joined Apr 5, 2008
20,773
Hello,

Here is the little formula for impedance VS turns: Bertus

#### MikeML

Joined Oct 2, 2009
5,444
I need to know the relationship between the impedance ratio and the number turns of primary winding and the secondary winding of a transformer.

For an example if we take a transformer which has an impedance ratio of 1:13 what will be the number of turns of the primary winding and secondary winding?

Then, what would be the case if it is a center tapped transformer?

Voltage transformation is proportional to turns ratio.
Current transformation is inversely proportional to turns ratio.
Impedance is proportional to the square of the turns ratio.

On a center-tapped winding, the impedance end to end is four times the impedance between center tap and either end.