A transformer has 500 turns on the primary and 100 turns on the secondary. The secondary supplies 20V and is connected to a 10 ohm load. The primary current is
- 2 amps.
- 0.4 amps.
- 10 amps.
Explanation
The secondary current is 20 V / 10 ohms = 2 A. Primary current relates to secondary by the inverse turns ratio: Ip = Is x (Ns/Np) = 2 x (100/500) = 0.4 A. Equivalently, the 40 W secondary power divided by the 100 V primary gives 0.4 A. The 2 A answer is the secondary, not the primary, current.
ravi_u5 asking:
HOW????
Community Comments (3)
D
dimky Posts: 514 16.12.2013 / 16:51
Secondary current = V/R = 20/10 = 2A.
Primary current = 2A/5 = 0.4A.
Primary current = 2A/5 = 0.4A.
O
oladejip Posts: 3 27.12.2013 / 09:36
V=500*20/100.
Vp=100v
V=IR
100=x * 10
x=100/10
Is= 10A
P=IV=k
10 * 20 = 100 * x
x= 200/100
Ip=2A
Ans=2A
Vp=100v
V=IR
100=x * 10
x=100/10
Is= 10A
P=IV=k
10 * 20 = 100 * x
x= 200/100
Ip=2A
Ans=2A
D
dimky Posts: 514 28.12.2013 / 20:20
Oladejip, your calculations are wrong. Voltage in secondary is 20 volts, so current in secondary is 2 amps. Don't confuse people please. :)
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