Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Characteristic impedance

  1. Jun 25, 2012 #1
    1. The problem statement, all variables and given/known data
    Transmission line is designed so it has selfinductance, L = 7.0x10^-7 Hm^-1 & signal speed 70% of c
    Find characteristic impedance

    2. Relevant equations
    Z = √L0/C0 Ω
    v = 1/ √L0C0

    3. The attempt at a solution
    L = 7.0x10^-7 Hm^-1
    v = 0.7c
    (c = 3x10^8 ms^-1)

    7(3x10^8)/10 = 1/√7.0 * C0
    C0 = √((10(7.0x10^-7))/(7*3x10^8))
    C0 = √ 3.33x10^-15
    C0 = 5.77x10^-8 F

    Z = √L0/C0
    Z = √7.0x10^-7/5.77x10^-8
    Z = 3.4 Ω

    Which isn't in the park as far as expected result goes, so AGAIN, please could you show me where I went wrong.
  2. jcsd
  3. Jun 25, 2012 #2
    OK, OK I get it.
    Forgot to square, but square rooted instead.
    All sorted.
    Last edited: Jun 25, 2012
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook