Does a Step-Up Transformer Increase Power? Evaluate the statement: “A step-up transformer steps up power.”

Introduction / Context:
Understanding how voltage, current, and power transform is essential for safe and efficient power system design. This question targets the common misconception that raising voltage automatically raises power inside an ideal transformer.

Given Data / Assumptions:

• Ideal transformer unless losses are explicitly considered.
• Input and output measured at transformer terminals.
• External load determines real power transfer.

Concept / Approach:

A step-up transformer increases secondary voltage and proportionally decreases secondary current such that (neglecting losses) input power approximately equals output power. Real devices have small copper and core losses; therefore, output power is slightly less than input power. The transformer does not create power; it changes voltage and current levels.

Step-by-Step Solution:

Verification / Alternative check:

Efficiency tests (load tests) show P_out = η * P_in with η slightly less than 1. When voltage is stepped up, current steps down, maintaining similar power levels.

Why Other Options Are Wrong:

Claims that power increases ignore current reduction. Power factor does not enable power creation. Ideal operation certainly does not increase power; it conserves it (minus losses).

Common Pitfalls:

Using P = V^2/R blindly without recognizing that the effective R “seen” at the secondary is transformed by the turns ratio, which also changes current accordingly.

Final Answer:

False