An ideal transformer has primary-to-secondary turns ratio 2:100. Find secondary voltage for a 25 V AC primary.

Solution & explanation

1. Given: Nₚ = 2; Nₛ = 100; Vₚ = 25 V.

2. For an ideal transformer supplied with AC, voltage ratio equals turns ratio.

   $$\frac{V_s}{V_p}=\frac{N_s}{N_p}$$

3. Multiply both sides by the primary voltage.

   $$V_s=\frac{N_s\times V_p}{N_p}$$

4. Insert the given values.

   $$V_s=\frac{2500}{2}$$

5. Multiply first, then divide.

   $$V_s=\frac{2500}{2}=1250$$

6. This is a step-up transformer because the secondary has more turns.

7. State the result with units: Vₛ = 1250 V.

Vₛ = 1250 V