8/13/2019 Chapter 2 Part2

1/11

LNI @ Network Analysis 1 1

METHODS OF ANALYSIS (cont..)

2.8 NODAL ANALYSIS

Circuit analysis using nodevoltage as circuit variables.

Steps:

Select a node as

reference node. Assignvoltage to the n nodes

Apply KCL to each of thenon reference nodes.Ohms Law use to expresscurrent in terms of thenode voltages.

Solve the resultingequations to get the nodevoltages.

8/13/2019 Chapter 2 Part2

2/11

LNI @ Network Analysis 1 2

METHODS OF ANALYSIS (cont..)

SupernodeFormed by enclosing a (dependent / independent)voltage source connected between two non-reference nodes.

8/13/2019 Chapter 2 Part2

3/11

LNI @ Network Analysis 1 3

Example 2.1b (3.1): Find V1 and V2using nodal analysis.

Ans: V1 = 13.33V

V2 = 20V

8/13/2019 Chapter 2 Part2

4/11

LNI @ Network Analysis 1 4

Exercise 2.1b (pp 3.6) Find V1 ,V2 and

V3 using nodal analysis.

Ans: V1 = 80V

V2 = -64V

V3 = 156V

8/13/2019 Chapter 2 Part2

5/11

LNI @ Network Analysis 1 5

Example 2.2b (3.3): Find V1 ,V2 and V3using nodal analysis.

Ans:

V1 = -7.333 V

V2 = -5.333 V

8/13/2019 Chapter 2 Part2

6/11

LNI @ Network Analysis 1 6

CHAPTER 2 (Cont)

METHODS OF ANALYSIS

2.9 MESH ANALYSIS

Circuit analysis using mesh current as variables.

Steps:

Assign mesh current to the n meshes

Apply KVL to each of the n meshes. Ohms Law use to express voltage in terms of the mesh

currents

Solve the resulting equations to get the mesh currents.

8/13/2019 Chapter 2 Part2

7/11

LNI @ Network Analysis 17

METHODS OF ANALYSIS (cont..)

Supermesh

Occurs when two meshes have a(dependent / independent)current source.

Steps: Assign mesh current to the nmeshes

Apply KVL to each ofthe n meshes.

Apply KCL to a nodebranches where the twomeshes intersect.Solve the equations.

8/13/2019 Chapter 2 Part2

8/11

LNI @ Network Analysis 18

Example 2.3b (3.5): Find I1,I2 and I3using mesh analysis.

Apply KVL at loop a

a b

)1(51015

0101051501015 21

BA

BAA

II

III

VV

Apply KVL at loop b

)(5.05.0

101020

)2(101020

0101046

010 543

aII

II

II

IIII

VVV

AB

AB

AB

ABB

B

Substitutes (a) into (1)

AIII

AII

AII

II

II

B

A

AA

BA

0

1

1

55.05.01015

51015

213

2

1

8/13/2019 Chapter 2 Part2

9/11

LNI @ Network Analysis 19

Example 2.4b (p3.41): Find I1,I2 and I3and I using mesh analysis.

Ans: i = 1.118 A

8/13/2019 Chapter 2 Part2

10/11

LNI @ Network Analysis 110

Exercise 2.2b: Find I1 and I2 using mesh

analysis.

8/13/2019 Chapter 2 Part2

11/11

LNI @ Network Analysis 111

Example 2.5b (pp 3.7): Find IA ,IB and

IC using mesh analysis.

Apply KVL at loop b

)1(0248

ACB III

Loop a & c supermesh loop

)2(6I6I12I2

0I8II4II26

BCA

CBCBA

a

b

c

Apply KVL at loop a & c

)3(3 AC

II

Apply KCL at node 1

Substitutes the equation tofind I1 and I2

IA = 3.474A

IB = 0.4737A

IC = 1.1052A