Function of a Transformer Evaluate the statement: “A transformer changes AC to DC.”

Introduction / Context:
Separating the roles of magnetic and semiconductor devices is crucial in power electronics. Transformers alter AC voltage and provide isolation, while conversion between AC and DC requires rectification and filtering.

Given Data / Assumptions:

• Two-winding power transformer operating on AC.
• Optional downstream rectifier and filter not included unless specified.
• Steady-state operation at line frequency or switching frequency.

Concept / Approach:

A transformer alone cannot produce DC from AC. It changes AC voltage level (and provides isolation) via electromagnetic induction. AC-to-DC conversion requires a rectifier (diodes or controlled devices) and typically a smoothing network (capacitor, inductor) to reduce ripple.

Step-by-Step Solution:

Verification / Alternative check:

Bench experiment: a transformer secondary waveform remains AC; attach a diode bridge and a filter to obtain DC, confirming role separation.

Why Other Options Are Wrong:

Center taps, filters, or frequency do not change the fact that rectification is necessary; the transformer alone cannot create DC.

Common Pitfalls:

Calling the entire supply “the transformer,” when the rectifier and filter stages are actually responsible for DC output.

Final Answer:

False