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

System Loss In Terms of I why not V?

  1. Mar 31, 2015 #1
    We all know that the system loss in transmission line is i^2R. So, in order to reduce the loss we diminish the current flow through the line by means of transformer.
    My question is i can also calculate system loss by the formula v^2/R where v is the potential across transmission line. So, shouldn't we reduce the voltage instead of current in that sense?
  2. jcsd
  3. Mar 31, 2015 #2
    in this case it would be the V DROP along the T line.... not the applied voltage.
  4. Mar 31, 2015 #3


    User Avatar
    Science Advisor

    At radio frequencies, as a signal travels along a transmission line energy is lost, mostly by I2R to the resistance of the line. But the ratio of voltage to current on the line is determined by the characteristic impedance of the line. So, stricktly speaking, it is power that is attenuated along a line of fixed characteristic impedance, unless there is reflected energy.

    That is why losses are specified using logarithmic ratios, in dB per set length.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook