Chapter 4

Question 1

Important Definitions
node
essential node
path

Answer 1

node A point where two or more circuit elements join

essential node A node where three or more circuit elements join

path A trace of adjoining basic elements with no
elements included more than once

Question 2

Important Definitions 2
branch
essential branch

Answer 2

branch A path that connects two nodes

essential branch A path which connects two essential nodes without
passing through an essential node

Question 3

Important Definitions 3
loop
mesh
planar circuit

Answer 3

loop A path whose last node is the same as the starting node

mesh A loop that does not enclose any other loops

planar circuit A circuit that can be drawn on a plane with no
crossing branches

Question 4

The Systematic Approach

Answer 4

Question 5

Node-Voltage Method

Answer 5

The node-voltage method works with both planar
and nonplanar circuits. A reference node is chosen
from among the essential nodes. Voltage variables
are assigned at the remaining essential nodes, and
Kirchhoff’s current law is used to write one equation
per voltage variable. The number of equations is ne - 1
, where ne is the number of essential nodes.

Question 6

The mesh-current method

Answer 6

The mesh-current method works only with planar
circuits. Mesh currents are assigned to each mesh,
and Kirchhoff’s voltage law is used to write one
equation per mesh. The number of equations is b - (n-1)
, where b is the number of branches in
which the current is unknown, and n is the number of
nodes. The mesh currents are used to find the branch
currents.

Question 7

Supernode

Answer 7

In circuit theory, a supernode is a theoretical construct that can be used to solve a circuit. This is done by viewing a voltage source on a wire as a point source voltage in relation to other point voltages located at various nodes in the circuit, relative to a ground node assigned a zero or negative charge

Question 8

Supernode example

Answer 8

Question 9

Supermesh

Answer 9

A supermesh occurs when a current source is contained between two essential meshes. The circuit is first treated as if the current source is not there. This leads to one equation that incorporates two mesh currents.

Question 10

Supermesh example

Answer 10

Question 11

Node-Voltage vs. Mesh-Current

Answer 11

Question 12

Source transformations

Answer 12

Source transformation is the process of simplifying a circuit solution, especially with mixed sources, by transforming voltage sources into current sources, and vice versa, using Thévenin’s theorem and Norton’s theorem respectively.

Question 13

Source transformations allow us to exchange a voltage source (vs ) and a series resistor (R) for a current
source ( is) and a parallel resistor (R) and vice versa.

Answer 13

Question 14

Thévenin equivalents and Norton equivalents

Answer 14

hévenin’s and Norton’s equivalent are circuit simplification techniques that focus on terminal behavior. This Theorem says that any circuit with a voltage source and a network of resistors can be transformed into one voltage source and one resistor.

Question 15

Thévenin equivalents and Norton equivalents

explained

Answer 15

Question 16

TheMaximum Power Transfer Theorem is one of the essential network theories. The maximum power transfer theorem____________________________________________________________

Answer 16

The Maximum Power Transfer Theorem is one of the essential network theories. The maximum power transfer theorem helps us deduce the maximum external power generated with a finite internal resistance, in electrical circuit systems.

Question 17

Maximum Power Transfer

Answer 17

Question 18

Superposition

Answer 18

Question 19

Summary

Answer 19