PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

Fourier and Laplace 423

30

20

10

− 10

− 2

− 1

− 2

0

0246

− 2 0

0

1

2

3

1

0

2

3

4

(^246) − 2 0246
− 2
−0.5
0.5
0
0
1
1.5
246
time (sec) time (sec)
Amplitude (amps)
Amplitude (volts)
Amplitude (amps)
Amplitude (amps)
v(t) versus t (sym. Laplace) ir(t) versus t (sym. Laplace)
ic(t) versus t (sym. Laplace) il(t) versus t (sym. Laplace)
FIGURE 4.69
Plots of the symbolic solutions of Example 4.15.
Example 4.16
The switch of the circuit of Figure 4.70 closes at t = 0, assuming that the circuit is ini-
tially relaxed, obtain analytical expressions of i(t), vl(t), vr(t), and vc(t) for t ≥ 0.
Create the script MATLAB fi le RLC_series that returns the analytical and symbolic
(Laplace) plots of i(t), vl(t), vr(t), and vc(t), over the range 0 ≤ t ≤ 10 s. Also verify KVL
given by
v(t) = vl(t) + vr(t) + vc(t) over the given time range
v(t) = 10sin(3t)
R = 4 Ω L = 2 H
C =1/20 F
switch closes at t = 0
i(t)
FIGURE 4.70
Circuit diagram of Example 4.16.