Transformer fundamentals — if the secondary voltage is stepped up, is the secondary current stepped down (and vice versa)? Assume an ideal transformer with negligible losses and constant power transfer.

Introduction / Context:
This statement checks a core idea of transformers used in power systems and electronics. In an ideal transformer, power on the primary side equals power on the secondary side, ignoring losses. Therefore, when voltage is changed by the turns ratio, current must change inversely so that the product of voltage and current stays approximately constant.

Given Data / Assumptions:

• Ideal transformer operation with negligible copper and core losses.
• Turns ratio defined as Np:Ns where Np is primary turns and Ns is secondary turns.
• Sine wave steady state with no saturation.

Concept / Approach:
For an ideal transformer, Vp/Vs = Np/Ns and Ip/Is = Ns/Np. Combining the two relations gives Vp * Ip ≈ Vs * Is, which is constant power transfer in the ideal case. Hence, if the secondary voltage is stepped up, the secondary current must be stepped down proportionally so that power balance is satisfied. The reverse happens for a step down in voltage.

Step-by-Step Solution:

Verification / Alternative check:
A numerical example makes the point. Suppose Vp = 120 V, Ip = 2 A, and Ns/Np = 2. Then Vs = 240 V and Is = 1 A, giving 240 V * 1 A = 240 W which closely matches the primary 120 V * 2 A = 240 W in the ideal case. The inverse relation between voltage and current is evident.

Why Other Options Are Wrong:

• “False” contradicts the transformer current ratio derived from Faraday’s law and ideal power conservation. A higher secondary voltage without a lower secondary current would imply power creation in the transformer, which is not possible.

Common Pitfalls:
Confusing real devices with ideal behavior. Real transformers have copper loss, core loss, and limited regulation, but the inverse relation between voltage and current still describes the dominant behavior for design estimates.

Final Answer:
True