A transformer with primary 100 turns and secondary 200 turns, input 120V, what is the output?

A transformer with primary 100 turns and secondary 200 turns, input 120V, what is the output?

• A. 240 V
• B. 120 V
• C. 60 V
• D. 480 V

Answer: (A)

Voltage in a transformer is set by the turns ratio. For an ideal transformer, Vs = Vp × (Ns / Np). With 100 primary turns and 200 secondary turns, Ns/Np = 200/100 = 2. The input is 120 V, so the output is 120 × 2 = 240 V. The secondary voltage is doubled relative to the input. The other voltages would correspond to different turns ratios: 120 V would require Ns/Np = 1; 60 V would require Ns/Np = 0.5; 480 V would require Ns/Np = 4. Here the turns ratio is 2, so 240 V is correct.

Voltage in a transformer is set by the turns ratio. For an ideal transformer, Vs = Vp × (Ns / Np). With 100 primary turns and 200 secondary turns, Ns/Np = 200/100 = 2. The input is 120 V, so the output is 120 × 2 = 240 V. The secondary voltage is doubled relative to the input. The other voltages would correspond to different turns ratios: 120 V would require Ns/Np = 1; 60 V would require Ns/Np = 0.5; 480 V would require Ns/Np = 4. Here the turns ratio is 2, so 240 V is correct.