In an ideal transformer, the ratio of secondary voltage to primary voltage equals the turns ratio.

• A. Turns Ratio.
• B. Capacitance.
• C. Frequency.
• D. Resistance.

Answer: (A)

In an ideal transformer, the voltages on the primary and secondary windings are scaled directly by the number of turns on each winding. The induced EMF in each winding is proportional to its turns, and the two windings share the same magnetic flux in the core, so the voltage ratio equals the turns ratio: V_s / V_p = N_s / N_p. This means the secondary voltage is the primary voltage multiplied by how many more (or fewer) turns the secondary has. Power is conserved in the ideal case, so V_p I_p = V_s I_s and the currents invert with the turns ratio.

Capacitance, frequency, and resistance don’t set this voltage ratio in the ideal model. Capacitance isn’t part of the transformer action; frequency doesn’t define the turns ratio (though it can affect real-world behavior and impedance); resistance introduces losses and voltage drop in non-ideal transformers.