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Help: line transmission question

  1. Jan 7, 2009 #1
    Hi
    I am trying to calculate impedance in a line transmission but cant seem to figure it out :(
    i have so far undertood that it is calculated by zo = R+jwL/G+jwC

    The values i have found so far to help me with the task are:
    R =100 ohms
    L=225 micro henry
    C = 9.3 Nano farads
    G = 0.01 S

    Can anyone get back to me asap with some help as i have got cswk in for today and am REALLY struggling :(

    Regards
    Dan
     
  2. jcsd
  3. Jan 7, 2009 #2
    I don't follow??

    Where are those values in a transmission line? Per metre?

    Time and time again people get a poor response because their question is vague.
     
  4. Jan 7, 2009 #3
    Hi Dan
    use conjugate multiplication!!
    multiply (R+jwL) and (G-jwC) in the numerator..(G+jwC) and (G-jwC) in the Dr.
    Substitute...w^2 = (1/LC)
     
  5. Jan 7, 2009 #4
    yeah i guess its per metre...
     
  6. Jan 8, 2009 #5
    You miss the square root!!! Z0=SQRT[(R+jwL)/(G+jwC)]

    I don't know how you get the numbers. I think it should be close approx. Make sure you use meter, farad/meter, henry/meter etc. for calculation. I am not 100% sure.
     
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