A transformer with more turns on the secondary than the primary is called a step-up transformer.

A transformer with more turns on the secondary than the primary is called a step-up transformer.

• A. Isolation transformer
• B. Step-up transformer
• C. Auto-transformer
• D. Step-down transformer

Answer: (B)

When the secondary has more turns than the primary, the output voltage is increased relative to the input because the transformer’s voltage ratio follows the turns ratio. In an ideal transformer, Vout/Vin equals Nsec/Npri. If Nsec > Npri, that ratio is greater than one, so the secondary voltage “steps up.” Power stays roughly the same (ignoring losses), so the current on the secondary drops accordingly: Isec ≈ (Npri/Nsec) × Ipri. Context helps: a transformer with equal turns on primary and secondary is typically used for isolation or a near-equal voltage transfer, not stepping up or down. An auto-transformer uses a single winding with a tap and can act as step-up or step-down but lacks the isolation of a two-winding transformer. A step-down transformer has fewer turns on the secondary than the primary. So, having more turns on the secondary than the primary is what makes it a step-up transformer.

When the secondary has more turns than the primary, the output voltage is increased relative to the input because the transformer’s voltage ratio follows the turns ratio. In an ideal transformer, Vout/Vin equals Nsec/Npri. If Nsec > Npri, that ratio is greater than one, so the secondary voltage “steps up.” Power stays roughly the same (ignoring losses), so the current on the secondary drops accordingly: Isec ≈ (Npri/Nsec) × Ipri.

Context helps: a transformer with equal turns on primary and secondary is typically used for isolation or a near-equal voltage transfer, not stepping up or down. An auto-transformer uses a single winding with a tap and can act as step-up or step-down but lacks the isolation of a two-winding transformer. A step-down transformer has fewer turns on the secondary than the primary.

So, having more turns on the secondary than the primary is what makes it a step-up transformer.