Which component is primarily responsible for the voltage change from primary to secondary in a distribution transformer?

• A. Primary winding
• B. Core
• C. Secondary winding
• D. Terminal blocks

Answer: (C)

Voltage change in a distribution transformer comes from electromagnetic induction between windings through a shared magnetic path. When the primary is energized, it creates magnetic flux in the core that links both windings. The voltage on the secondary is determined by the turns ratio—the number of turns in the secondary compared to the primary. More turns on the secondary produce a larger induced voltage (or a proportionally different voltage for step-down). The secondary winding is the part where that induced voltage appears and is delivered to the load, so it primarily sets the transformed voltage. The primary winding supplies the magnetic field, the core provides a low-reluctance path for the flux, and terminal blocks are just connection points.