EXPERIMENT # 1
Aim: - To verify KVL and KCL.
Apparatus: - Bread board, resistors, D.C. power supply, Ammeter (0-50 mA), Multimeter,
connecting wires
Circuit Diagram:Theory: KVL:
The directed sum of the electrical potential differences (voltage) around any closed circuit is
zero.
or
More simply, the sum of the emfs in any closed loop is equivalent to the sum of the potential
drops in that loop.
or
The algebraic sum of the products of the resistances of the conductors and the currents in them in
a closed loop is equal to the total emf available in that loop.
The principle can also be stated as:
Here, n is the total number of voltages measured.
The sum of all the voltages around the loop is equal to zero. v 1 + v2 + v3 - v4 = 0
KCL:
At any node (junction) in an electrical circuit, the sum of currents flowing into that node is equal
to the sum of currents flowing out of that node.
or
The algebraic sum of currents in a network of conductors meeting at a point is zero.
Recalling that current is a signed (positive or negative) quantity reflecting direction towards or
away from a node.
This principle can be stated as:
n is the total number of branches with currents flowing towards or away from the node.
The current entering any junction is equal to the current leaving that junction. i1 + i4 = i2 + i3
Procedure:1.
2.
3.
4.
Connect the circuit as shown in circuit diagram on the breadboard.
Set the value of voltage source Vdc at 5 volt.
Measure the potential difference across resistors R 1, R2, R3, R4 using multimeter.
Similarly connect the ammeter to measure the value of current I, I1 and I2 in each branch.
5. Repeat the experiment for Vdc =10V and 15V.
Observation Table:
KVL:
Sr. Vdc
No. (Volts)
1
2
3
Measured Voltage Theoretical Voltage Measured Voltage
Theoretical Voltage
(Loop ABCD)
(Loop ABCD)
(Loop CDEF)
(Loop CDEF)
(In Volts)
(In Volts)
(In Volts)
(In Volts)
V1 V2 V1+V2+V V1 V2 V1+V2+V V3 V4 V2+V3+V4 V3 V4 V2+V3+V4
5
10
15
KCL:
Sr. No.
Vdc (V)
1
2
3
5
10
15
I1
Conclusion:
Measured Current
I2
I3
I1+ I2+I3
I1
Theoretical Current
I2
I3
I1+ I2+I3
EXPERIMENT # 2
Aim: - To verify Superposition theorem.
Apparatus: - Kit for Superposition Theorem, DC Voltmeter (0-20 V), DC Dual Power
variable voltage source
Theory: The superposition theorem for electrical circuits states that the response (Voltage or
Current) in any branch of a bilateral linear circuit having more than one independent source
equals the algebraic sum of the responses caused by each independent source acting alone, while
all other independent sources are replaced by their internal impedances. To ascertain the
contribution of each individual source, all of the other sources first must be "turned off" (set to
zero) by:

Replacing all other independent voltage sources with a short circuit (thereby eliminating
difference of potential. i.e. V=0, internal impedance of ideal voltage source is ZERO
(short circuit)).

Replacing all other independent current sources with an open circuit (thereby eliminating
current. i.e. I=0, internal impedance of ideal current source is INFINITE (open circuit).

This procedure is followed for each source in turn, and then the resultant responses are
added to determine the true operation of the circuit. The resultant circuit operation is the
superposition of the various voltage and current sources.
Circuit Diagram:-
Procedure:1. Connect the circuit as shown in figure.
2. Set the value of voltage of 12 V source to 0 V and slowly increase the voltage of 9 V
source to 9 V. Measure the potential difference across 500  resistor.
3. Set the value of voltage of 9 V source to 0 V and slowly increase the voltage of 12 V
source to 12 V. Measure the potential difference across 500  resistor.
4. Slowly increase the value of voltage of 9 V source to 9 V and then slowly increase the
voltage of 12 V source to 12 V. Measure the potential difference across 500  resistor.
Observation Table:
V1=9 volts
V2=12 volts
V – Practical V-Theoretical
Conclusion:
Voltage across 500  Resistor
V1=9 volts
V2=0 volts
V – Practical V - Theoretical
V1=0 volts
V2=12 volts
V – Practical V - Theoretical
EXPERIMENT # 3
Aim: - To verify Thevenin’s theorem.
Apparatus: - Bread board, resistors, D.C. power supply, Ammeter (0-50 mA), Multimeter,
connecting wires
Circuit Diagram:Theory: A linear resistive circuit seen (observed) from two of its terminals (a two-terminal
circuit) is equivalent to a Thévenin connected between the two terminals. This is called Thévenin
equivalent of the circuit.
The Thévenin’s Theorem states that “any two terminal ab of a network composed of
linear passive and active elements may be replaced by simple equivalent circuit consisting of an
equivalent circuit voltage source V Th in series with an equivalent resistance R Th”. The voltage
VTh is equal to the potential difference between two terminals ab caused by the active network
with no external resistance connected to these terminals. The series resistance R Th is equivalent
resistance looking back in to the network at terminals ab with all the sources within the network
made inactive.
Figure shows a two-terminal linear-resistive circuit. When observed from its terminals the circuit
appears as a Thévenin source with voltage VTh (termed the Thévenin voltage) and resistance R Th
(termed the Thévenin resistance). Consider a linear resistive one-port N. Let R Th be the
equivalent resistance across N when all the independent sources are set to zero. V Th(t) be the
open-circuit port voltage of N Let Neq be the one-port formed by a series connection of an
independent voltage source vs(t) = VTh(t) and a resistor with resistance RTh. Under these
conditions, the one-port N and the one-port Neq have exactly the same v-i characteristics.
Procedure:1. Apply dc voltage across terminals 1-1’, call this voltage as Vdc.
2. Connect voltmeter across terminals 2-2’ and measure voltage on voltmeter. This voltage
is known as open circuit voltage or Thevenin‛s voltage (V Th).
3. Vary the dc voltage across terminals 1-1’ and repeat step 2, take three readings at Vdc=5
V, Vdc=10 V, Vdc= 15 V.
4. Disconnect the applied voltage at terminals 1-1’ and voltmeter at terminals 2-2’.
5. Now short terminals 1-1’ and connect multimeter across terminals 2-2’l . With the help of
multimeter measure resistance between terminals 2-2’. This is known as Thevenin‛s
resistance (RTh).
6. Calculate VTh and RTh by theoretical calculations, the theoretical values and measured
values of VTh and RTh should be approximately equal.
7. Connect load resistor RL across terminals 2-2’ and measure IL for applied dc voltages of
Vdc=5 V, Vdc=10 V, Vdc= 15 V.
8. Calculate theoretical value of IL at Vdc=5 V, Vdc=10 V, Vdc= 15 V and compare with the
practical value obtained in step 7.
Observation Table:
Sr. No.
Vdc
RTh
1
2
3
Conclusion:
5
10
15
Measured Value
VTh
IL
RTh
Theoretical Value
VTh
IL
EXPERIMENT # 4
Aim: - To verify Norton’s theorem.
Apparatus: - Bread board, resistors, D.C. power supply, Ammeter (0-50 mA), Multimeter,
connecting wires
Circuit Diagram:Theory: This theorem is in fact an alternative to the Thevenin’s theorem. In this theorem
“any two terminal ab of a network composed of linear passive and active elements may be
replaced by simple equivalent circuit consisting of an equivalent circuit current ISC (IN) in
parallel with an equivalent resistance RN. The current ISC is equal to the short circuit current
through terminals ab caused by the active network. The parallel resistance R N is equivalent
resistance looking back in to the network at terminals ab with all the sources within the network
made inactive.
Consider a linear resistive one-port N. Let R N be the equivalent resistance across N when all the
independent sources are set to zero IN(t) be the short-circuit port current of N (owing out) Let N eq
be the one-port formed by a parallel connection of an independent current source i s(t) = IN(t) and
a resistor with resistance RN. Under these conditions, the one-port N and the one-port Neq have
exactly the same v-i characteristics.
Procedure:1. Apply d. c. voltage across terminals 1-1’ called this voltage Vdc.
2. Connect ammeter across terminals 2-2’ and measure current, this is the short circuit (Isc)
current.
3. Vary the d. c. voltage across terminals 1-1’ and repeat step 2, take three readings at V dc=5
V, Vdc=10 V, Vdc= 15 V.
4. Disconnect the applied voltage at terminals 1-1’ and ammeter at terminals 2-2’.
5. Short terminals 1-1’ and connect Multimeter (keep it on resistance range) across
terminals 2-2’ and note down the reading, this resistance is known as R eq= RTh.
6. Calculate Isc and RTh by using formulae, the calculated values and measured values of Isc
and RTh should be approximately equal.
7. Connect RL across terminals 2-2’ and measure IL by ammeter for applied dc voltages of
Vdc=5 V, Vdc=10 V, Vdc= 15 V.
8. Calculate theoretical value of IL at Vdc=5 V, Vdc=10 V, Vdc= 15 V and compare with the
practical value obtained in step 7.
Observation Table:
Sr. No.
Vdc
ISC
1
2
3
Conclusion:
5
10
15
Measured Value
Req= RTh
IL
ISC
Theoretical Value
Req= RTh
IL
EXPERIMENT # 5
Aim: - To verify Reciprocity Theorem.
Apparatus: - Bread board, resistors, D.C. power supply, Ammeter (0-50 mA), Multimeter,
connecting wires
Circuit Diagram:Theory: The ratio of excitation to response remains invariant in a reciprocal network with respect to an
interchange between the points of application of excitation and measurement of response.
In a bilateral network having one independent source and no dependent sources, an important
relation exists between a source voltage in one branch and current in some other branch.
If a source of V Volts, located at 1-1’ in a network composed of linear bilateral circuit elements
produces a current I Ampere at a 2-2’ in the network, the same source of V Volts acting at
second poin1-1’, it will produce the same current at 2-2’.
Procedure:1.
2.
3.
4.
Connect the circuit as shown in circuit diagram.
Apply 15 V d. c. voltage across terminals 1-1’ call this voltage V dc.
Connect ammeter across terminals 2-2’ and measure current I with ammeter.
Remove voltage source and ammeter and interchange their position in the circuit, i.e.
connect Vdc = 15 V across 2-2’ and ammeter across 1-1’ and measure current I.
Observation Table:
V1-1’
Conclusion:
I 2-2’
V 1-1’/I 2-2’
I 1-1’
V 2-2’
V 2-2’/I 1-1’
EXPERIMENT # 6
Aim: - To verify Maximum Power Transfer Theorem.
Apparatus: - Bread board, resistors, D.C. power supply, Ammeter (0-50 mA), Multimeter,
connecting wires
Circuit Diagram:Theory: Maximum amount of power will be dissipated by a load resistance when that load resistance is
equal to the Thevenin/Norton resistance of the network supplying the power. If the load
resistance is lower or higher than the Thevenin/Norton resistance of the source network, its
dissipated power will be less than maximum. Thus the condition for maximum power transfer
can be stated as:
RL = RTh
The theorem applies to the maximum power, and not to the maximum efficiency. If the
resistance of the load is made larger than the source, then efficiency is higher, since most of the
power is generated in the load, but the overall power is lower since the total resistance goes up.
If the internal impedance is made larger than the load then most of the power ends up
being dissipated in the source, and although the total power dissipated is higher, due to a lower
circuit resistance, it turns out that the amount dissipated in the load is reduced.
The efficiency is only 50% when maximum power transfer is achieved, but approaches
100% as the load resistance approaches infinity (or the source resistance approaches zero),
though the total power level tends towards zero. When the load resistance is zero, all the power
is consumed inside the source (the power dissipated in a short circuit is zero) so the efficiency is
zero.
Procedure:1. Apply d. c. voltage across terminals 1-1’ called this voltage Vdc.
2. Connect ammeter across terminals 2-2’ and measure current, this is the short circuit (Isc)
current.
3. Vary the d. c. voltage across terminals 1-1’ and repeat step 2, take three readings at V dc=5
V, Vdc=10 V, Vdc= 15 V.
4. Disconnect the applied voltage at terminals 1-1’ and ammeter at terminals 2-2’.
5. Short terminals 1-1’ and connect Multimeter (keep it on resistance range) across
terminals 2-2’ and note down the reading, this resistance is known as R eq= RTh.
6. Calculate Isc and RTh by using formulae, the calculated values and measured values of Isc
and RTh should be approximately equal.
7. Connect RL across terminals 2-2’ and measure IL by ammeter for applied dc voltages of
Vdc=5 V, Vdc=10 V, Vdc= 15 V.
8. Calculate theoretical value of IL at Vdc=5 V, Vdc=10 V, Vdc= 15 V and compare with the
practical value obtained in step 7.
Observation Table:
Vdc = ________
RTh = ________
Sr. No.
RL
1
33 Ω
2
110 Ω
3
440 Ω
4
1 kΩ
5
2 kΩ
Conclusion:
IL
VL
P
EXPERIMENT # 7
Aim: - To determine Y-Z parameters of a two – port network.
Apparatus: - Bread board, resistors, D.C. power supply, Ammeter (0-50 mA), Multimeter,
connecting wires
Circuit Diagram:Theory: Figure below shows a general two port network. I1 and V1 are input current and
voltage, respectively. Also, I2 and V2 are output current and voltage, respectively. It is assumed
that the linear two-port circuit contains no independent sources of energy and that the circuit is
initially at rest (no stored energy). Furthermore, any controlled sources within the linear two-port
circuit cannot depend on variables that are outside the circuit.
Z-parameters of a two port network can be defined as:
The Z-parameters can be found as follows:
The z-parameters are also called open-circuit impedance parameters since they are obtained as a
ratio of voltage and current and the parameters are obtained by open-circuiting port 2 ( I2 = 0) or
port1 ( I1 = 0).
and Y-parameters can be defined as
The y-parameters can be found as follows:
The y-parameters are also called short-circuit admittance parameters. They are obtained as a ratio
of current and voltage and the parameters are found by short-circuiting port 2 (V2 = 0) or port 1
(V1 = 0).
Procedure:1. Connect the circuit on the bread board through the connecting wires.
2. At port 1 apply the desired voltage say 10 volts and open circuit the 2nd port and note
down voltmeter and ammeter readings as V1 & I1 to calculate the value of Z11 .
3. In the same way, find out Z12 , Z 21& Z22 as per their conditions.
4. At port 1 apply the desired voltage say 10 volts and short circuit the 2nd port and note
down voltmeter and ammeter readings as V1 & I1 to calculate the value of Y11 .
5. In the same way, find out Y12 , Y21 & Y22 as per their conditions.
Observation Table:
Sr.
No.
1
2
Z-parameters
V1=15 V
V2=15 V
I2=0 A
I1=0 A
I1
V1
V2
I2
Y-parameters
V1=15 V
V2=15 V
V2=0 A
V1=0 A
I1
I1
I2
I2
Computed Values from Observation Table:
Z-parameters
Sr. No.
1
2
Conclusion:
z11
z21
z12
z22
Y-parameters
y11
y21
y12
y22
EXPERIMENT # 8
Aim: - To determine ABCD parameters of a two – port network.
Apparatus: - Bread board, resistors, D.C. power supply, Ammeter (0-50 mA), Multimeter,
connecting wires
Circuit Diagram:Theory: The ABCD-parameters are known variously as chain, cascade, or transmission line parameters.
ABCD-parameters of a two port network can be defined as:
Where:
A=(V1/V2)|I2=0
B=(V1/-I2)|V2=0
C=(I1/V2)|I2=0
D=(I1/-I2)|V2=0
A represents the open-circuit transfer function, B represents the short-circuit transfer impedance,
C represents the open-circuit transfer admittance, and D represents the short-circuit current ratio.
For reciprocal networks, AD-BC=1. For symmetrical networks, A=D. For networks which are
reciprocal and lossless, A and D are purely real while B and C are purely imaginary.
The relationship between the Z-parameters and ABCD parameters is as follows:
A= Z11/Z21
B=(Z11 Z22 -Z12 Z21 )/Z21
C=1/Z21
D =Z22/Z21ÞD real
Procedure:1. Connect the circuit on the bread board through the connecting wires.
2. At port 1 apply the desired voltage say 15 volts and open circuit the 2nd port and note
down voltmeter and ammeter readings as V2 and I1 to calculate the values of parameters
A and C. .
3. At port 1 apply the desired voltage say 15 volts and short circuit the 2nd port and note
down readings of I1 and I2 to calculate the values of parameters B and D.
4. Obtain the values of ABCD parameters through Z-parameters obtained in experiment 7
and compare with the values of ABCD parameters obtained in this experiment.
Observation Table:
Sr.
No.
1
2
V1=15 V
I2=0 A
I1
V2
V1=15 V
V2=0 A
I1
I2
Computed Values of ABCD parameters:
From above observation table
A
Conclusion:
B
C
D
From values of Z-parameters of
Experiment # 7
A
B
C
D