Transformer Turns Ratio

Transformer Turns Ratio

Transformer Turns Ratio

For an ideal transformer:

**Vₛ/Vₚ = Nₛ/Nₚ**

where:

`Vₚ` = primary voltage `Vₛ` = secondary voltage `Nₚ` = primary turns `Nₛ` = secondary turns

Step-Up

If:

Nₛ > Nₚ

then:

Vₛ > Vₚ

Step-Down

If:

Nₛ < Nₚ

then:

Vₛ < Vₚ

Worked Example

Primary voltage:

`Vₚ = 20 V`

Primary turns:

`Nₚ = 100`

Secondary turns:

`Nₛ = 500`

Then:

`Vₛ/20 = 500100 = 5`

So:

**Vₛ = 100 V**

Current Ratio

For an ideal transformer:

**VₚIₚ = VₛIₛ**

so increasing voltage results in decreasing current.

Transformer Turns Ratio — Advanced