In a step-up transformer, which side has more turns?

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Multiple Choice

In a step-up transformer, which side has more turns?

In a transformer, the voltage change is set by the turns ratio. For a step-up, the output winding must have more turns than the input winding. Since Vs/Vp = Ns/Np, making Ns larger than Np makes the output voltage bigger than the input. So the side with more turns is the secondary. This also explains why the current reverses: Is ≈ Ip × (Np/Ns), so the secondary current is lower when the voltage is higher. If the turns were equal, there would be no voltage change; if the primary had more turns, the transformer would step down instead.

In a transformer, the voltage change is set by the turns ratio. For a step-up, the output winding must have more turns than the input winding. Since Vs/Vp = Ns/Np, making Ns larger than Np makes the output voltage bigger than the input. So the side with more turns is the secondary. This also explains why the current reverses: Is ≈ Ip × (Np/Ns), so the secondary current is lower when the voltage is higher. If the turns were equal, there would be no voltage change; if the primary had more turns, the transformer would step down instead.

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