PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

184 Practical MATLAB® Applications for Engineers

then

vR(t) = V 0 − vC(t) = Ve−t/ for R = 1, 2, and 5 Ω

and

it()



vt

R

V

R

R et

() 0 /

where τ = RC.

MATLAB Solution

% Script file:RC

vctR _ 1=dsolve(‘0.5*Dy+y=10’,’y(0)=0’,’t’);

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

vctR _ 5=dsolve(‘2.5*Dy+y=10’,’y(0)=0’,’t’);

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

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

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

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

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

vctR _ 1

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

vctR _ 2

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

vctR _ 5

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

figure(1)

ezplot(vctR _ 1,[0 4]);

hold on

ezplot(vctR _ 2,[0 4]);

hold on

ezplot(vctR _ 5,[0 4]);

hold on

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

xlabel(‘time t/sec’)

ylabel(‘voltage ‘)

title(‘Voltages across C for R=1,2 and 5 are:’)

figure(2)

disp(‘The voltages across R’)

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

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

vr1=10-vctR _ 1

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

vR2=10-vctR _ 2

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

vR5=10-vctR _ 5

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

ezplot(10-vctR _ 1,[0 4]);

hold on

ezplot(10-vctR _ 2,[0 4]);

hold on

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

hold on