PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

Fourier and Laplace 425

0

0

2

4

− 4

− 10

− 20

− 2

5100

20

10

10

0

− 10

− 20

20

10

0

05

0

5

10

− 10

− 5

5 10

Amplitude (amps) Amplitude (volts)

Amplitude (volts) Amplitude (volts)

time (sec)

0510

time (sec)

vl(t) versus tvc(t) versus t

i(t) versus t vr(t) versus t

FIGURE 4.71

Plots of i(t), vl(t), vr(t), and vc(t) of Example 4.16.

plo t(t,vlt);title(‘vl(t) v s t’);yla b e l(‘A m plitu d e (v olts)’);

xlabel(‘time (sec)’)

%plot of VC(t) vs t

VCnum = [0 0 0 0 300];

VCden = [1 2 19 18 90];

vct = impulse(VCnum,VCden,t);

subplot(2,2,4)

plo t(t,v c t);title(‘v c(t) v s t’);yla b e l(‘A m plitu d e (v olts)’);

xlabel(‘time (sec)’)

figure(2)

subplot(2,1,1)

plot(t,it,t,vrt,t,vlt,t,vct)

title(‘Plots of: i(t) vs.t, vr(t) vs.t, vl(t)vs.t, and vc(t) vs.t’)

axis([0,5,-20,20])

ylabel(‘Amplitude (amps/volts)’)

subplot(2,1,2)

vsourse = vrt+vlt+vct;

plot(t,vsourse);

title(‘[vr(t)+vl(t)+vc(t)] vs. t (verifies KVL)’)

xlabel(‘time (sec)’);

ylabel(‘ Amplitude (volts)’)

axis([0 5 -12 12])

The script fi le RLC_series is executed and the results are shown in Figures 4.71

and 4.72.