This document presents Thevenin's and Norton's theorems. It explains that Thevenin's theorem states that any linear circuit with voltage and current sources and resistors can be simplified to an equivalent circuit with a voltage source in series with a resistor. The document outlines the steps to use Thevenin's theorem to simplify a circuit. It also discusses Norton's theorem and how to convert a circuit into an equivalent Norton circuit using Norton's current and resistance. The limitations of Thevenin's theorem are provided.

1. THEVENIN’S AND NORTON’S
THEOREM
PRESENTED BY
P.ESWAR SAI (18981A0237)
P.SUPRIYA (18981A0238)
P.MOHAN (18981A0239)
P.NITISH (18981A0240)
P.SANJAYKUMAR(18981A0241)
UNDER THE GUIDANCE
Dr.SUDHEER VINNAKOTI
ASST PROFESSOR
RAGHU ENGINEERING COLLEGE
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2.  INTRODUCTION
 WHAT IS THEVENIN'S THEOREM?
 STEPS TO SOLVE THEVENIN'S
THEOREM
 LIMAITATION OF THEVENIN'S THEOREM
CONTENTS
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3. INTRODUCTION
 Thevenin’s Theorem is a very important and useful
theorem.
 It is a method for the reduction of a portion of a complex
circuit into a simple one.
 It reduces the need for repeated solutions of the same
sets of equations.
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4. NORTON’S THEOREM
 Any linear, active, bilateral dc network
having a number of voltage sources and/or
current sources with resistances can be
replaced by a simple equivalent circuit
having single current source (IN) in parallel
with a single resistance (RN).
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5. “The Thevenin Theorem explains how to simplify a complex
circuit. It states that any linear circuit with only voltage
sources, current sources and resistors can be simplified to a
voltage source with a series resistor".
But what does this really mean?
Sometimes a picture says more than thousand words, so here are
two pictures to explain what Thevenin’s Theorem is about.
WHAT IS THEVENIN'S THEOREM?
…can be represented by this
simple circuit
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6. STEPS TO SOLVE THEVENIN'S THEOREM
This is the circuit to explain Thevenin's theorem. Thevenin's theorem
can be explained with the help of the following simple example. The
steps are as follow:
Step1:Load resistance(RL) remove from the circuit terminal and for the
network showning.
Step2:The open circuit voltage(voc) which appear across terminala and
is calculated as
Voc is called the "Thevenin's voltage" (VTH).
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7. Step 3:Removing the battery from the circuit leaving the internal
resistance (r) of the battery behind it (in fig.) when viewed from
terminals a and b , the internal resistance of the circuit is given by
This resistance Riis called Thevenin's
equivalent resistance (RTH).
Step 4:Thevenin's equivalent circuit is drawn as shown in
(in fig) and RL is reconnected across terminals a and b. The
current through RL is given.
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8. Procedure for converting any circuit into Norton's equivalent circuit
Calculate Norton Current
Step 1: remove the load resistance RL (through which current is required)
and short circuit it. Let terminals of load are labelled as a-b. Therefore a-b
is the short circuited.
Step 2: Find the current through the terminal a-b by applying KCL, KVL,
Ohm’s law or Superposition principle. This current is the short circuit
current and it is known as Nortons equivalent current (IN).
Calculate Norton Resistance (equal to Thevinin resistance)
Step 3: Set all Independent voltage Sources as short circuit and Current
Sources open circuit. Dependent sources will not be changed
Step 4: Calculate the resistance as “seen” through the terminals a-b into the
network. This resistance is known as Norton’s equivalent resistance (RN ).
Draw Equivalent Circuit
Step 5: Replace the entire network by Nortons equivalent current (IN) in
parallel with Norton’s equivalent resistance (RN ) and connect the load
resistance RL.
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9. RAGHU ENGINEERING COLLEGE
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Theoritical Calculations
Circuit1
0.157Ai1
0.25*0.628
(200/800)*ii1
0.628i
220/350
Req220/200i
150Req
120000/800Req
200)/800*(600
200toparallel600
600100500
seriesinare500,100
,KVLUsing










10. RAGHU ENGINEERING COLLEGE
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110vV
200*0.55V
r*iV
0.55i
220/400i
v/ri
400200200
seriesinare200,200
2CIRCUIT








11. RAGHU ENGINEERING COLLEGE
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0.824Ai
220/266.67i
66.67220/200i
66.67Requ
20000/300
200)/300*(100
parallelinare100,200
3Circuit






12. RAGHU ENGINEERING COLLEGE
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49.133
824.0/110
/
*
4




th
th
R
R
ivr
riv
circuit

13. RAGHU ENGINEERING COLLEGE
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Ai
i
rvi
CIRCUIT
173.0
49.633/110
/
5




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Ai
i
CIRCUIT
173.0
21.0*824.0
6



15. RAGHU ENGINEERING COLLEGE
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CIRCUIT 1

16. RAGHU ENGINEERING COLLEGE
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CIRCUIT 2

17. RAGHU ENGINEERING COLLEGE
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CIRCUIT 3

18. RAGHU ENGINEERING COLLEGE
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CIRCUIT 4

19. RAGHU ENGINEERING COLLEGE
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CIRCUIT 5

20. RAGHU ENGINEERING COLLEGE
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CIRCUIT 6

21. LIMITATION OF THEVENIN'S THEOREM :
1. Thevenin Theorem is not applicable to the circuits that contain
nonlinear elements like transistors and diodes etc.
2. It is not applicable to the circuits having unilateral elements like
diode etc.
3. Thevenin's Theorem cannot be used for the circuits that contain
magnetic coupling between load and any other circuit element.
4. It is Not possible to apply the Thevenin's theorem to the circuits
containing load in series or parallel with controlled or dependent
sources.
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22. RAGHU ENGINEERING COLLEGE
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