In an ideal transformer with 50 turns on the primary and 100 turns on the secondary, what is the voltage relationship?

In an ideal transformer with 50 turns on the primary and 100 turns on the secondary, what is the voltage relationship?

• A. Secondary voltage equals primary voltage.
• B. Secondary voltage is double the primary voltage.
• C. Secondary voltage is half the primary voltage.
• D. Voltage cannot be determined.

Answer: (B)

In an ideal transformer, voltages scale with the turns ratio. The secondary-to-primary voltage equals the secondary-to-primary turns ratio: V_s / V_p = N_s / N_p. Here N_s = 100 and N_p = 50, so the ratio is 100/50 = 2. Therefore the secondary voltage is twice the primary voltage: V_s = 2 V_p. For example, if the primary has 230 V, the secondary would be about 460 V (ignoring losses). The current reverses proportionally so that power stays the same: I_s = (N_p / N_s) I_p = 0.5 I_p. Real transformers have small losses, but the basic relationship holds.

In an ideal transformer, voltages scale with the turns ratio. The secondary-to-primary voltage equals the secondary-to-primary turns ratio: V_s / V_p = N_s / N_p. Here N_s = 100 and N_p = 50, so the ratio is 100/50 = 2. Therefore the secondary voltage is twice the primary voltage: V_s = 2 V_p. For example, if the primary has 230 V, the secondary would be about 460 V (ignoring losses). The current reverses proportionally so that power stays the same: I_s = (N_p / N_s) I_p = 0.5 I_p. Real transformers have small losses, but the basic relationship holds.