If a power supply outputs 12 volts and 3 amps, what is its maximum wattage?

If a power supply outputs 12 volts and 3 amps, what is its maximum wattage?

• A. 18 W
• B. 36 W
• C. 54 W
• D. 72 W

Answer: (B)

Power is found by multiplying voltage by current. With 12 volts and 3 amps, the maximum power is 12 × 3 = 36 watts. The other numbers would require different voltage or current (for example, 18 watts would need 1.5 A at 12 V, and 54 watts would need 4.5 A at 12 V), so 36 watts is the correct maximum given these ratings.

Power is found by multiplying voltage by current. With 12 volts and 3 amps, the maximum power is 12 × 3 = 36 watts. The other numbers would require different voltage or current (for example, 18 watts would need 1.5 A at 12 V, and 54 watts would need 4.5 A at 12 V), so 36 watts is the correct maximum given these ratings.