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Resistor and Current Source in Parallel with Short Circuit?

  1. Oct 7, 2012 #1
    This circuit is really confusing me. I'm trying to find i using KVL and KCL. What's throwing me off is the short circuit effectively created by the inductor. I know that the whole circuit can't be short circuited because there is a current source that is preventing all of i from going through the inductor-branch. Is current going through the resistor as well, now? I need to figure out what the current is supposed to be doing here.

    Here's what I have:

    i +2i = 3i (in the wire leading to the inductor and resistor in parallel) This current will all go through the short circuit and none through the 200ohm resistor. But here it's odd because according to KVL, if I choose the loop to be through the 10V source, the 625 resistor and then the short circuit, the current i is 10/625 A. BUT doesn't the current source have to have the same voltage drop as the short circuit since they are in parallel? And how can a short circuit have any voltage drop at all? I have no idea.

    Attached Files:

    Last edited: Oct 7, 2012
  2. jcsd
  3. Oct 7, 2012 #2
    You are right on all counts. Not sure what you're confused about.
  4. Oct 7, 2012 #3


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    Science Advisor

    A current source can deliver a current into a short circuit even though this means it will have zero volts across it.

    Your diagram shows uF as the unit for inductance. It could probably mean uH.

    This assumes the inductor has no resistance and the supply is pure DC.
  5. Oct 7, 2012 #4
    Okay, I understand. I didn't realize that was possible, haha. Thanks!
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