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Low pass filter

  1. Mar 17, 2009 #1


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    Hi all,

    Here is a picture of two circuits.
    The one at the left is stimulated with a current source and the other with a voltage source.
    They give the same results V(1) = V(2).
    Is it possible to say that the primer is a low pass filter?

    Attached Files:

  2. jcsd
  3. Mar 18, 2009 #2
    Yes. Somewhere buried away in your textbook is something call source transformation. If you have a voltage source with a series resistor, you can transform it to a current source in parallel with the same resistance. The current source is simply the original voltage source divided by the resistor.
  4. Mar 18, 2009 #3


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    Thanks Corneo,

    I wasn't aware of such circuit but find a good description in this http://books.google.com/books?id=sx...r=&ei=v5_AScGeEp-8zgTIwOH3Bw&hl=fr#PPA118,M1"
    What is its interest by the way?
    Normally the simple nature of RC cells give us an entry point and an exit one. This permits a cascading with two or more filters.
    In this configuration the applied source is modified by the filter but I see no way to assemble multiple filters?
    Last edited by a moderator: Apr 24, 2017
  5. Mar 18, 2009 #4
    What good is source transformation? Honestly I don't know. I have never ever had to use it at in career so far (2 years). If you want to cascade the filter, you could just place the next filter in parallel to the resistor and cap, the currents sources would add. The resistors would combine in parallel; the caps would add in value.
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