PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

164 Practical MATLAB® Applications for Engineers

>> Vmax = v(40)

Vmax =

32.9680

>> for k=41:200

t(k)=k/20; % 2 < t < 10

v(k)=Vmax*exp(-(t(k)-t(40))/tau2);

t(40)=40/20=2sec=t1

i(k)= -v(k)/(R2+R3);

end

>> % plot the Voltage VC(t)

>> subplot(2,1,1)

>> plot(t,v)

>> axis([0 10 0 40]);

>> title (‘Transients in the circuit of Fig 2.62’)

>> xlabel(‘time in sec’), ylabel(‘Voltage vc(t)’)

>> grid on

>> % plot the current IC (t)

>> subplot(2,1,2)

>> plot(t,i)

>> axis([0 10 -13 15]);

>> xlabel(‘time in sec’),ylabel(‘Current ic(t)’)

>> grid on

The plots of the Voltage vc(t) and the Current ic(t) versus t are shown in Figure 2.63.

FIGURE 2.63
Transient plots of Example 2.19.

40

30

20

10

0

01 2 34 5

time in sec

678910

0

− 10

− 5

0

Current ic(t)

Voltage vc(t)

5

10

15

12345

time in sec

678910

Transients in the circuit of Fig. 2.62