- #1
dwn
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Homework Statement
Image
Homework Equations
KCL
DRIVEN RL CIRCUIT
The Attempt at a Solution
I got the right answer after trying a different tactic, but I don't understand why it is done this way.
My first approach:
KCL: 100/45 + 60/2 = iL for t < 0
32.22 - (100/45)e^(-45*(0.00001)/0.5) = 29.999 A (NOT THE RIGHT ANSWER)
Second approach:
30 - (100/45)e^(-45*(0.00001)/0.5) = 27.78 A
Why is the initial current 30 A? I know how they got it, but why didn't they use KCL? I mean what is happening to the 100 V source?