PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

Direct Current and Transient Analysis 193

The script fi le RC_ IC is executed, and the results and plots are shown as follows

(Figures 2.93 and 2.94):

>> RC _ IC

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

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

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

The voltage across C, vc(t) for t >0 is:

vct =

20-10*exp(-1/2*t)

The voltage across R=2 ohms is :

vrt =

10*exp(-1/2*t)

The current i(t) is :

it =

5*exp(-1/2*t)

********Verify solution******************

verify = 2*diff(vct,t)+vct

verify =

20

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

FIGURE 2.93

Plots of symbolic transient solutions of Example 2.27.

21.81.61.41.210.80.60.40.20

12

10

14

16

plots of: [vc(t), vr(t), and i(t)] versus t

21.81.61.41.21

t

t

0.80.60.40.20

6

4

8

10

21.81.61.41.21

time in sec

0.80.60.40.20

3

2

4

5

vr(t) in volts

vc(t) in volts

it(t) in amps