PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

152 Practical MATLAB® Applications for Engineers

ANALYTICAL Solution

Recall that

R

L

A


 (1 TC * ) ∆T

where ρ is the Greek letter rho, TC = 0.00393 (the temperature coeffi cient of copper), and

R = ρ(10 0/1)(1 + 0.00393 * ∆T).

MATLAB Solution

>> T = 0:10:100;

>> TC = 0.00393;

>> L =100;

>> Rho =10.37;

>> A=1;

>> R= (Rho*100./A)*(1+TC.*T);

>> result = [T’ R’];

>>disp(‘**********************************’)

>> disp(‘Temperature (°C)****Resistance (in Ohms)’);

>>disp(‘**********************************’)

>>disp(result)

>>disp(‘**********************************’)

*****************************************************

Temperature (°C)****Resistance (in Ohms)

*****************************************************

1.0e+003

0 1.0370

0.0100 1.0778

0.0200 1.1185

0.0300 1.1593

0.0400 1.2000

0.0500 1.2408

0.0600 1.2815

0.0700 1.3223

0.0800 1.3630

0.0900 1.4038

0.1000 1.4445

**************************************************

Example 2.12

Let the resistor RL shown in the circuit of Figure 2.50 vary over the range 0 Ω ≤ RL ≤ 10 Ω

in linear incremental steps of 0.25 Ω.

Write a program that returns the following plots:

1. IL versus RL


2. VL versus RL


3. [PRL = VL * IL] versus RL
   For each of the plots, determine the maximum of IL , V 2 , and PRL over the range

0 Ω ≤ RL ≤ 10 Ω, and verify that PRL-max ≠ IL-max (^) VL-max and PRL-max < IL-max (^) VL-max.
MATLAB Solution

VS =10;
RL = 0:0.25:10;
IL = VS./(5+RL);
VL = IL.*RL;
subplot (2,2,1)