138
Practical MATLAB
® Applications for Engineers
R.2.123 Finally, consider the two capacitors C 1 and C 2 connected in parallel with a current
(source) I o feeding the parallel combination as shown in Figure 2.37.
The currents I C1 and I C2 are evaluated by using the current divider rule as
follows:
I
C
C C
I
C1
o
ϭ ϩ
1
1
2
I
C
C C
I
C2
o
ϭ ϩ
2
1
2
2.4 Examples
Example 2.1
1. Determine the charge induced when a current of 1 A passes through a point during
2 min
2. Determine the number of electrons required to build up the charge of part 1
Solve this problem analytically and by using MATLAB.
ANALYTICAL Solution
Charge Q (coulombs) = I * t = 1 A * 2 min *
60 s
____
min
Q = 120 A s = 120 C
The number of electrons required to build up a charge of Q = 120 C is given by
Number of electrons 120 C *
1 electron
1.602 10 C
19
ϭ
ϫ
ϭ
ϫ
Ϫ
7 49 10
.
Ϫ Ϫ19 electrons
FIGURE 2.37
Current divider rule for capacitors in parallel.
C 1
C 2
I o
+
−
I C 1
I C 2
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7/23/2008 1:38:45 PM