An ideal step-down transformer has 1,200 turns in its primary coil and 60 turns in its secondary coil. If the primary alternating voltage is 240 V, what is the output voltage from the secondary coil?
Answer and explanation
Correct answer: B. 12 V
- Step 1: Transformer turns ratio formula: V_s / V_p = N_s / N_p. Step 2. Substitute values: V_s / 240 = 60 / 1200 => V_s / 240 = 1 / 20. Step 3. Solve: V_s = 240 / 20 = 12 V. Answer: 12 V. Why not the others: 24 V uses turns ratio 1/10; 6 V uses turns ratio 1/40; 48 V is a step-up calculation error.
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