Biomedical Engineering Reference
In-Depth Information
EXAMPLE PROBLEM 9.3
Find
R
EQ
and the power supplied by the source for the following circuit.
I
2
Ω
3
Ω
+
−
5 V
12
Ω
12
Ω
12
Ω
2
Ω
2
Ω
Solution
To solve for
R
EQ
, apply from right to left the parallel and series combinations. First, we have
two 2
O
resistors in parallel that are in series with the 3
O
resistor. Next, this group is in parallel
with the three 12
O
resistors. Finally, this group is in series with the 2
O
resistor. These combina-
tions are shown in the following figure and calculation:
I
2
Ω
3
Ω
+
−
12
Ω
12
Ω
12
Ω
2
Ω
2
Ω
5 V
2
2 = 1
Ω
Ω
Ω
12 12 12 = 4
3 + 1 = 4
Ω
4 4 = 2
Ω
2 + 2 = 4
R
EQ
¼
2
O þ
ð
ð
12
O k
12
O k
12
O
Þ k
ð
3
O þ
ð
2
Ok
2
O
Þ
Þ
Þ
0
@
0
@
1
A
k
0
@
1
A
1
A
1
1
¼
2
þ
3
þ
1
12
þ
1
12
þ
1
12
1
2
þ
1
2
¼
2
þ
ð
ðÞk
4
ð
3
þ
1
Þ
Þ ¼
2
þ
2
¼
4
O
Continued
