Help: line transmission question

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The discussion centers on calculating the impedance of a transmission line using the formula zo = √[(R + jωL)/(G + jωC)]. The user, Dan, provides specific values for resistance (R), inductance (L), capacitance (C), and conductance (G) but struggles with the calculation. Respondents emphasize the importance of using correct units and suggest using conjugate multiplication for the calculation. There is a reminder to ensure the values are per meter for accurate results. The conversation highlights the need for clarity in questions to receive effective assistance.
Danieljax88
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Hi
I am trying to calculate impedance in a line transmission but can't 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
 
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Where are those values in a transmission line? Per metre?

Time and time again people get a poor response because their question is vague.
 
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)
 
yeah i guess its per metre...
 
Danieljax88 said:
Hi
I am trying to calculate impedance in a line transmission but can't 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

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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