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RL Circuit

  • Thread starter vthokie11
  • Start date
  • #1
3
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Homework Statement


The switch in the circuit has been closed for a long time before opening at t = 0
a. Find i(t) across R3 for t>0.
b. Find i(t) across R2 for t>0.

I have attached the circuit.

Homework Equations





The Attempt at a Solution


The only thing I know for this problem is that when a switch has been in a certain state for a long time an inductor acts essentially like a wire (no resistance) and when the state changes the inductor has infinite resistance.
 

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Answers and Replies

  • #2
1,762
59
To solve this you need to know the formula for di/dt for RL circuits. Isn't this in your textbook or covered by lecture?
 
  • #3
3
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I apologize....I thought that I included the relevant equations.....but this is what I know:

hw7-eq.jpg


What I don't understand is what the change in time is...I really don't know how to go about solving this problem...and I have no examples from lecture...all I have from lecture is basically the 2 equations I have included. Any help would be greatly appreciated...Thanks.
 
  • #4
3
0
So I've done some work and this is what I've came up with...I'm not sure if this is even remotely close:

I applied KVL's around each loop

HW7-KVL.jpg


HW7-KVLeq-1.jpg


Am I even on the right track with this?
 

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