A step-down transformer has a power output of 50 W and efficiency of 80%. if the mains supply voltage is 200 v, calculate the primary current of the transformer.
-
0.31 A
- 3.20 A
- 3.40 A
- 5.00 A
The correct answer is: A
Explanation
Efficiency = (power output)/power input x 100%
= 1s VS x 100% 1p
Vp
∴ (80)/100 = (50)/IP x 200
I P = (50 x 100)/80 x 200 = 0.3125 A
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