Which part determines the voltage step ratio in a transformer?

• A. The core material.
• B. The wire gauge.
• C. The number of turns in the coils.
• D. The input frequency.

Answer: (C)

The voltage step ratio is determined by the turns ratio between the primary and secondary windings. In an ideal transformer, the voltages relate as Vp/Vs = Np/Ns, so the number of turns on each winding directly sets how much voltage is gained or reduced. More turns on the secondary than the primary produce a higher output voltage (step-up), while fewer turns produce a lower output voltage (step-down).

The core material mainly affects how well magnetic flux is transferred and losses, not the voltage ratio. The wire gauge influences resistance and current-carrying capability, not the voltage transformation. The input frequency doesn’t set the ratio; it affects flux, losses, and impedance but not the fundamental voltage ratio set by turns.