Network Theorms

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Network Theorems
UNIT 2 NETWORK THEOREMS
Structure
2.1 Introduction
Objectives
2.2 Networks
2.2.1 Sign Convention
2.2.2 Active and Passive Elements
2.2.3 Unilateral/Bilateral Elements
2.2.4 Lumped and Distributed Networks
2.2.5 Linear and Non-Linear Elements
2.3 Superposition Theorem
2.3.1 Statement
2.3.2 Explanation of the Theorem
2.4 Thevenin’s Theorem
2.5 Norton’s Theorem
2.5.1 Statement
2.5.2 Explanation of the Theorem
2.6 Reciprocity Theorem
2.6.1 Statement and Explanation
2.6.2 Explanation of the Theorem
2.7 Maximum Power Transfer Theorem (MPTT)
2.7.1 Statement
2.7.2 Proof of the Theorem
2.7.3 Limitation of MPTT
2.8 Star and Delta Transformation
2.9 Theorems in AC Circuits
2.10 Summary
2.11 Answers to SAQs
2.1 INTRODUCTION
In the previous unit, you have studied about various circuit elements and circuit simplification methods. In this unit, you will learn different terms and definitions which are useful in network analysis. We will discuss different types of network theorem and their applicability in networks. At the end, we will consider the star and delta transformation.
The objective of analyzing a particular circuit is to determine the various responses such as current, voltage etc. which are produced in the circuit by the presence of active elements. Objectives
After studying this unit, you should be able to
• give the elementary description of network terms and definitions,
• explain the superposition theorem, reciprocating theorem and maximum power transfer theorem,
• describe the Thevenin’s and Norton’s theorems, and
• explain star delta transformation.
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Electrical Technology 2.2 NETWORKS
We can define a network as a complex form or an electric circuit which consist of a number of inter-connected single circuit elements. A network consists of different elements. The elements are represented by network branches and the different junctions can be treated as nodes.
In Figure 2.1, there is a network