This document discusses the key concepts of nodes, branches, and loops in electric circuits. It defines nodes as junction points where two or more circuit elements are connected. Branches refer to the path between two nodes through a circuit element. Loops are closed paths in a circuit formed by branches that start and end at the same node without crossing any intermediate nodes twice. The document uses diagrams to illustrate these concepts and their application in representing electric circuits.

1. Presented by
Dr. R. RAJA, M.E., Ph.D.,
Associate Professor, Department of EEE,
Muthayammal Engineering College, (Autonomous)
Namakkal (Dt), Rasipuram – 637408
MUTHAYAMMAL ENGINEERING COLLEGE
(An Autonomous Institution)
(Approved by AICTE, New Delhi, Accredited by NAAC, NBA & Affiliated to Anna University),
Rasipuram - 637 408, Namakkal Dist., Tamil Nadu, India.
Circuit Theory:
Nodes, Branches and Loops of a Circuit

2. Introduction
 An electric circuit based on three concepts, namely, node, branch and loop. As
per definition, an electric network is a combination of interconnected circuit
elements.
 A network may or may not provide closed path to the electric current to flow.
But, an electrical circuit may be a combination of one or more networks which
gives closed path to the electric current.
 That means, when one or more networks are interconnected together to
complete one or more paths to the current, an electric circuit is formed.
An electric circuit does have three conceptual things as mentioned below.
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3. Nodes of Electric Circuit
 The point through which an circuit element is connected to the circuit is called
node.
 It is better to say, node is a point where, terminal of two or more circuit
elements are connected together. Node is a junction point in the circuit.
 In the above circuit nodes are indicated by bullets.
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4.  NB:- If three is no element between two or more connected adjacent nodes,
these nodes can be recombined as a single node.
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Contd….

5.  Finally, the circuit can be redrawn as,
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Contd….

6. Branch of Electric Circuit
 The elements connected to an electric circuit is generally two terminal
element.
 When, one circuit element is connected to the circuit, it connects itself
through both of its terminals, to be a part of a closed path.
 Any of the circuit elements, when connected to the circuit, it is
definitely connected between two nodes of the circuit.
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7.  When an element exists between two nodes, the path from one node to another
through this element is called branch of the circuit.
 The branch of an electric circuit can be defined more precisely, as the portion of
the circuit between two nodes which can deliver or absorb energy.
 As per this definition, the short circuit between two nodes is not referred as
branch of electric circuit.
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Contd….

8. Loops in Electric Circuit
 An electric circuit has numbers of nodes.
 If one starts from one node and after going through a set of nodes returns to
same starting node without crossing any of the intermediate node twice, he has
travels through one loop of the circuit.
 Loop is any closed path in the circuit formed by branches.
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9. Thank You
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