In a transformer, which equation relates the voltages and turns of the two coils?

In a transformer, which equation relates the voltages and turns of the two coils?

• A. V1/N2 = V2/N1
• B. V1 = V2
• C. N1 = N2
• D. V1/N1 = V2/N2

Answer: (D)

In an ideal transformer, voltages scale with the number of turns on each winding. The voltages follow the ratio V1/V2 = N1/N2. If you rearrange that relationship by dividing both sides by N1N2, you get V1/N1 = V2/N2. That is why the correct form is V1 divided by N1 equals V2 divided by N2. This means if the secondary has more turns than the primary, the output voltage increases proportionally; if it has fewer turns, the voltage decreases. The other options don’t reflect the correct proportionality: one swaps the turns, another claims equal voltages regardless of turns, and the last would require equal turns.

In an ideal transformer, voltages scale with the number of turns on each winding. The voltages follow the ratio V1/V2 = N1/N2. If you rearrange that relationship by dividing both sides by N1N2, you get V1/N1 = V2/N2. That is why the correct form is V1 divided by N1 equals V2 divided by N2.

This means if the secondary has more turns than the primary, the output voltage increases proportionally; if it has fewer turns, the voltage decreases. The other options don’t reflect the correct proportionality: one swaps the turns, another claims equal voltages regardless of turns, and the last would require equal turns.