A transformer has primary turns N_p = 100 and secondary turns N_s = 50. What is the turns ratio and voltage ratio?

A transformer has primary turns N_p = 100 and secondary turns N_s = 50. What is the turns ratio and voltage ratio?

• A. Turns ratio N_p/N_s = 2:1; V_p:V_s = 2:1; V_s = V_p/2
• B. Turns ratio N_p/N_s = 1:2; V_p:V_s = 1:2; V_s = 2V_p
• C. Turns ratio N_p/N_s = 1:1; V_p:V_s = 1:1; V_s = V_p
• D. Turns ratio N_p/N_s = 2:1; V_p:V_s = 1:2; V_s = 2V_p

Answer: (A)

In an ideal transformer, voltages scale with the turns on each winding, so the voltage ratio matches the turns ratio: V_p / V_s = N_p / N_s. With N_p = 100 and N_s = 50, the turns ratio is 100/50 = 2, i.e., 2:1. That means the primary voltage is twice the secondary, and the secondary voltage is half of the primary (V_s = V_p / 2). The description that states the turns ratio is 2:1 and the voltage ratio is 2:1, with V_s = V_p/2, is the consistent one. The other descriptions would require different turn counts or imply a contradictory voltage relationship.

In an ideal transformer, voltages scale with the turns on each winding, so the voltage ratio matches the turns ratio: V_p / V_s = N_p / N_s. With N_p = 100 and N_s = 50, the turns ratio is 100/50 = 2, i.e., 2:1. That means the primary voltage is twice the secondary, and the secondary voltage is half of the primary (V_s = V_p / 2). The description that states the turns ratio is 2:1 and the voltage ratio is 2:1, with V_s = V_p/2, is the consistent one. The other descriptions would require different turn counts or imply a contradictory voltage relationship.