PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

Direct Current and Transient Analysis 181

MATLAB Solution

% Script file: RL _ vol _ plots

itR _ 1=dsolve(‘Dy+y=10’,’y(0)=0’,’t’);

itR _ 2=dsolve(‘Dy+2*y=10’,’y(0)=0’,’t’);

itR _ 5=dsolve(‘Dy+5*y=10’,’y(0)=0’,’t’);

disp(‘*********** R E S U L T S **************’)

disp(‘*****************************************’);

disp(‘The voltages across R = 1, 2 and 5 (in Ohms) are:’);

disp(‘***************************’);

disp(‘***************************’);

vr_1=itR_1*1

disp(‘***************************’);

vr _ 2=itR _ 2*2

disp(‘***************************’);

vr_5=itR_5*5

disp(‘***************************’);

figure(1)

ezplot(itR _ 1*1,[0 4]);

hold on

ezplot(itR _ 2*2,[0 4]);

hold on

ezplot(itR _ 5*5,[0 4]);

hold on

grid on;axis([0 3 0 11])

xlabel(‘time t/sec’)

ylabel(‘voltage ‘)

title(‘Voltages across R for, R=1,2 and 5 ‘)

figure(2)

disp(‘***************************’);

disp(‘The voltages across L=1’)

disp(‘ for R=1,2 and 5 (in Ohms) are:’);

disp(‘***************************’);

disp(‘***************************’);

vlr _ 1=10-itR _ 1*1

disp(‘***************************’);

vlr _ 2=10-itR _ 2*2

disp(‘***************************’);

vlr _ 5=10-itR _ 5*5

disp(‘***************************’);

ezplot(10-itR _ 1*1,[0 4]);hold on

ezplot(10-itR _ 2*2,[0 4]);hold on

ezplot(10-itR _ 5*5,[0 4]);

hold on

grid on;axis([0 3 0 11])

xlabel(‘time t/sec’)

ylabel(‘voltage ‘)

title(‘Voltages across L=1, for R=1,2 and 5’)

The script fi le RL_vol_plots is executed, and the results and plots are shown as follows:

>> RL _ vol _ plots

*******************R E S U L T S ********************

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

The voltages across R = 1, 2 and 5 (in Ohms) are:

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