Which are the essential parts of a transformer?

• A. Armature, Stator, Rotor
• B. Windings and yoke
• C. Primary coil, Secondary coil, Iron Core
• D. Casing and Insulation

Answer: (C)

A transformer works by transferring energy through a magnetic path between two windings. The essential parts are the primary coil, the secondary coil, and the iron core. The primary coil carries the input AC and, as current changes, it creates a changing magnetic flux. The iron core provides a low-reluctance path that concentrates and guides that flux to the secondary coil. The changing flux in the core induces a voltage in the secondary coil, delivering energy at the transformed voltage to the load. The turns ratio between the primary and secondary determines whether the voltage is stepped up or down. The casing and insulation are important for safety and durability but do not drive the energy transfer, and components like armature, stator, or rotor belong to other machines such as motors or generators. A transformer’s fundamental operation relies on two windings and a magnetic core, with the core often laminated to minimize losses.