Inductance of a Transmission Line

So, I'm supposed to create a function to calculate the total inductance when given the variables. This is what I have so far:

% Script file: myinductance.m

%

% Purpose:

% This program calculates the total inductance of a transmission line as

% a function of its length in kilometers, the spacing between the two

% conductors, and the diameter of each conductor.

% Known variables:

% D is the distance bewtween two conductors = 1.5 m

% r is the radius of each conductor = 2 cm

% Constant for permeability of free space:

mu0 = {4.*pi.*1e-7};

% The function of the inductance per meter of a single-phase two-wire

% transmission line is:

function inductance = myind(D, r, mu0)

inductance = (mu0./pi).*((1./4)+log(D./r));

end

It's not recognizing the name of the function (the "myind") and I'm not even sure where to go from here. ://

This is exercise 6.10 (p. 276) in "The Essentials of Matlab Programming" - Stephen J. Chapman.

[Star Strider]

How are you calling it?

[Sophia Bonifant]

myind (1.5, 2, mu0)

It's been saying my function "might be unused" and I don't know to fix it. I know it recognizes as a local function, but i also don't know what that is doing to my function.

Answer 1

[Star Strider]

The error I get is:

Operator './' is not supported for operands of type 'cell'.

because of:

mu0 = {4.*pi.*1e-7};

Since there is no need to create it as a cell array, removing the curly braces:

mu0 = 4.*pi.*1e-7;

and running:

% Script file: myinductance.m
%
% Purpose: 
%   This program calculates the total inductance of a transmission line as
%   a function of its length in kilometers, the spacing between the two
%   conductors, and the diameter of each conductor. 
% Known variables:
% D is the distance bewtween two conductors = 1.5 m 
% r  is the radius of each conductor = 2 cm
% Constant for permeability of free space:
mu0 = 4.*pi.*1e-7;
% The function of the inductance per meter of a single-phase two-wire
% transmission line is: 

Inductance = myind (1.5, 2, mu0)

function inductance = myind(D, r, mu0)
inductance = (mu0./pi).*((1./4)+log(D./r));
end

from the Command Window after saving it to my MATLAB path as ‘myinductance.m’ produces:

Inductance =
   -15.0728e-009

since in R2020a (and several previous releases/versions), functions at the end of script files are allowed.

Problem solved?

.

[Sophia Bonifant]

I think so! Thank you so much :))

[Star Strider]

My pleasure!

If my Answer helped you solve your problem, please Accept it!

.