If a transformer has turns ratio Np:Ns = 2:1, what is the voltage ratio Vp:Vs?

If a transformer has turns ratio Np:Ns = 2:1, what is the voltage ratio Vp:Vs?

• A. 1:2
• B. 2:1
• C. 3:2
• D. 2:3

Answer: (B)

In an ideal transformer, voltages scale directly with the turns. If the primary has twice as many turns as the secondary, the voltage ratio mirrors the turns ratio. So Vp:Vs = Np:Ns = 2:1. That means the primary voltage is twice the secondary voltage, i.e., Vs = Vp/2. The other ratios would not match the given turns relationship, so they don’t fit.

In an ideal transformer, voltages scale directly with the turns. If the primary has twice as many turns as the secondary, the voltage ratio mirrors the turns ratio. So Vp:Vs = Np:Ns = 2:1. That means the primary voltage is twice the secondary voltage, i.e., Vs = Vp/2. The other ratios would not match the given turns relationship, so they don’t fit.