1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

First order Circuit

  1. Nov 17, 2012 #1
    I'm not sure what happens when you replace the inductor with a short circuit. The current source is what throws me off.

    One thought I had was that you can remove the 6 and 2 kohm resistors, but then I don't know what ahppens to the current source.
    http://imgur.com/lks7y
    Thanks
     
  2. jcsd
  3. Nov 17, 2012 #2
    Everything you've said is right. The voltage across the inductor being 0 also means some current is flowing through the 3k resistor. The current source demands a certain current flow, so KCL should give you the inductor's steady current.
     
  4. Nov 17, 2012 #3
    So then are you saying that you remove the current source as well since the voltage around it is zero?
     
  5. Nov 17, 2012 #4
    The question is designed to trick your intuition. A current source can pull any amount of current no matter what the voltage across it is, including 0 volts.

    What you've said about the 2k and 6k resistors is correct -- the voltage across them is zero so Ohm's law gives zero current through them. The current source continues to draw 5mA no matter what.
     
    Last edited: Nov 17, 2012
  6. Nov 17, 2012 #5
    Ok, so then you're saying that there is 2mA of current traveling up [i(0) = -2] through the inductor?
     
  7. Nov 17, 2012 #6
    Yes, that's it.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: First order Circuit
  1. A first order ODE (Replies: 1)

  2. First Order circuit (Replies: 6)

Loading...