In a 4:1 step-up transformer, 120V is applied to the primary, and the load on the secondary is 1600 Ohms. What is the current in the primary?
- 0.075A
- 1.2A
- 3A
Explanation
The 4:1 step-up turns 120 V into 480 V across the 1600-ohm load, giving a secondary current of 480/1600 = 0.3 A and a load power of 144 W. With negligible losses the primary draws the same power, so primary current is 144 W / 120 V = 1.2 A, which is also four times the 0.3 A secondary current.
Richiegeee asking:
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Community Comments (1)
D
dimky Posts: 514 05.12.2015 / 14:52
Voltage in secondary = 4 * 120 = 480V.
Current in Secondary = 480/1600 (Ohm's Law) = 0.3A.
Current in Primary = 4 * 0.3A = 1.2A
Remember that current is stepped down Primary to Secondary in a step-up transformer.
Current in Secondary = 480/1600 (Ohm's Law) = 0.3A.
Current in Primary = 4 * 0.3A = 1.2A
Remember that current is stepped down Primary to Secondary in a step-up transformer.
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