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Unformatted text preview: ted differently. Why? Because an essential component of nodal
analysis is applying KCL, which requires knowing the current through
each element. There is no way of knowing the current through a voltage
source in advance. However, KCL must be satisﬁed at a supernode like
any other node. Hence, at the supernode in Fig. 3.7,
i1 + i4 = i2 + i3 (3.11a) or
v 1 − v2
v 1 − v3
v2 − 0 v3 − 0
To apply Kirchhoff ’s voltage law to the supernode in Fig. 3.7, we redraw
the circuit as shown in Fig. 3.8. Going around the loop in the clockwise
−v2 + 5 + v3 = 0 ⇒ v2 − v3 = 5 | v v From Eqs. (3.10), (3.11b), and (3.12), we obtain the node voltages. | e-Text Main Menu | Textbook Table of Contents | 5V
+ +− + v2
− (3.12) Figure 3.8 v3
− Applying KVL to a supernode. Problem Solving Workbook Contents 84 PART 1 DC Circuits
Note the following properties of a supernode:
1. The voltage source inside the supernode provides a constraint
equation needed to solve for the node voltages.
2. A supernode has no voltage of its...
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- Spring '12