EC 3271 – Circuits Analysis Lab Manual

This Lab Manual Prepared with the support of Mr.T.AntonyBaskar, Technical Assistant/ECE

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA

 EC 3271 – Circuits Analysis Lab Manual

EC3271 CIRCUITS ANALYSIS LABORATORY

1. Verifications of KVL & KCL.

2. Verifications of Thevenin & Norton theorem.

3. Verification of Superposition Theorem.

4. Verification of maximum power transfer Theorem

5. Determination of Resonance Frequency of Series & Parallel RLC Circuits.

6. Transient analysis of RL and RC circuits.

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 EC 3271 – Circuits Analysis Lab Manual

CIRCUIT DIAGRAM

TABULATION

Voltage Current
Applied
across across Resistance
S.No Voltage
resistor resistor R=V/I (Ω)
(Volts)
(volts) (mA)

CALCULATION

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 EC 3271 – Circuits Analysis Lab Manual

Ex.No:
VERIFICATION OF OHM’S LAW

AIM
To verify the Ohm’s law theoretically and practically for a given network.

APPARATUS REQUIRED

S.NO APPARATUS RANGE TYPE QTY

1. DC Regulated power supply (0-30V) - 1

2. Ammeter (0-100mA) MC 1
3. Voltmeter (0-10V) MC 1
4. Resistor 300 Ω - 1
5. Connecting wires - - -
6. Bread Board - - 1

STATEMENT
The Ohm’s law states that the voltage (V) across the two terminals of a conductor is
directly proportional to the current (I) flowing through it at constant temperature.

PROCEDURE
1. The connections are made as per the circuit diagram.
2. Switch ON the RPS and increase the applied voltage in steps and note down the current
flowing through the resistor and voltage across the resistor.
3. The same procedure is repeated for different values of applied voltage.
4. The observed readings are tabulated.

RESULT
Thus the Ohm’s laws are verified theoretically and practically for the given
circuit.

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 EC 3271 – Circuits Analysis Lab Manual

CIRCUIT DIAGRAM

KIRCHOFF’S CURRENT LAW

TABULATION

Practical Threoctical
Practical Practical
Applied Currents Currents
Incoming Outgoing
S.No voltage in
Current Current
Volts I1 I2 I3 I1 I2 I3
I1 I2+13

CALCULATION

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 EC 3271 – Circuits Analysis Lab Manual

Ex.No:
VERIFICATION OF KIRCHOFF’S LAW

AIM
To verify the Kirchoff’s current law and voltage law theoretically and practically for a
given network
APPARATUS REQUIRED
S.NO APPARATUS RANGE Type QNTY
1. DC Regulated power supply (0-30V) 1
2. Ammeter (0-10mA) MC 1
3. Ammeter (0-25mA) MC 2
4. Voltmeter (0-5V) MC 3
5. Resistor - Each 1
6. Connecting wires - - -
7. Bread Board 1

KIRCHHOFF’S CURRENT LAW

Kirchhoff’s current law (KCL) states that the algebraic sum of currents entering a
node is equal to the algebraic sum of currents leaving from a node.
Sum of Incoming currents = Sum of outgoing currents
KIRCHHOFF’S VOLTAGE LAW
Kirchhoff’s voltage law (KVL) states that the algebraic sum of all voltages around a
closed path (or loop) is zero.
PROCEDURE

Current Law
1. Connections are made as per the circuit diagram
2. Apply various voltages by using RPS and note down the currents I 1,I2 and I3 for the
corresponding voltages
3. Find the total current theoretically by using the formula I1= I2 + I3

Voltage Law

1. Connections are made as per the Circuit Diagram

2. Apply various voltages by using RPS and note down the corresponding voltages V 1,
V2 and V3.
3. Find the total Voltage theoretically by using the formula V= V 1+ V2 + V3

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 EC 3271 – Circuits Analysis Lab Manual

KIRCHHOFF’S VOLTAGE LAW

TABULATION

Practical Threoctical
Applied voltage Voltages (Volts) Voltages (Volts)
Voltage Drop
S.No in Volts
V1+V2+V3
(Voltage rise) V1 V2 V3 V1 V2 V3

CALCULATION:

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 EC 3271 – Circuits Analysis Lab Manual

RESULT

Thus the Kirchoff’s laws are verified theoretically and practically for the given circuit.

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA

 EC 3271 – Circuits Analysis Lab Manual

CIRCUIT DIAGRAM

Circuit (i)
Determination of IL when both V1 and V2 are active

Circuit (ii)
Determination of IL’ by removing V2

Circuit (iii)
Determination of IL’’ by removing V1

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 EC 3271 – Circuits Analysis Lab Manual

Ex.No:
VERIFICATION OF SUPERPOSITION THEOREM

AIM
To verify the Superposition theorem theoretically and practically for a given circuit
APPARATUS REQUIRED
S.NO APPARATUS RANGE TYPE QNTY
1. DC Regulated power supply (0-30)V - 2
2. Ammeter (0-50)mA MC 1
3. Resistor - Each 1
4. Connecting wires - - -
5. Bread Board - - 1

STATEMENT
The theorem states that the response in any element of a linear bilateral network
having two or more sources is the algebraic sum of the responses obtained by each source
acting individually while all other sources are set equal to zero.
PROCEDURE
A) Determination of IL’ by removing V2
1. Make connections as per the circuit diagram (iii).
2. Remove V2 by short circuiting the terminal.
3. Apply voltage V1 by using RPS and note down the current IL’.
B) Determination of IL’’ by removing V1
1. Make connections as per the circuit diagram (iv).
2. Remove V1 by short circuiting the terminal.
3. Apply voltage V2 by using RPS and note down the current I L’’.
C) Determination of IL when both V1 and V2 are active
1. Make connections as per the circuit diagram (ii).
2. Apply the voltage V1, V2 and note down the current IL
FORMULA USED
IL=IL’+IL’’
IL’- current through Ammeter by removing V2
IL’’- current through Ammeter by removing V1

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 EC 3271 – Circuits Analysis Lab Manual

PRACTICALTABULATION:

Considering Considering
Actual Circuit Sum Of Current
Source 1 Source 2
S.No

Source Source 2 Source 1 Source IL = IL’ + IL’

IL IL’ IL’’
1 (V1) (V2) (V1) 2 (V2)

THEORITICAL TABULATION:

Considering Considering
Actual Circuit Sum Of Current
Source 1 Source 2
S.No

Source Source 2 Source 1 Source 2 IL = IL’ + IL’

IL IL’ IL’’
1 (V1) (V2) (V1) (V2)

CALCULATION

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 EC 3271 – Circuits Analysis Lab Manual

RESULT
Thus the Super position theorem is verified theoretically and practically for the given
circuit.

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA

 EC 3271 – Circuits Analysis Lab Manual

Ex.No:
VERIFICATION OF MAXIMUM POWER TRANSFER THEOREM

AIM
To verify the Maximum power transfer theorem theoretically and practically for a
given circuit
APPARATUS REQUIRED
S.NO APPARATUS RANGE TYPE QTY
1. DC Regulated power supply (0-30)V 1
2. Ammeter MC 1
3. Voltmeter (0-10V) MC 1
4. Five dial decade resistance box - - 1
5. Resistors 10KΩ, 22KΩ - 1Each
6. Bread board - - 1
7. Connecting wires - - -

STATEMENT
Maximum power is transferred to the load when the load resistance equals the
Thevenin’s resistance as seen from the load (RL = RTh).
PROCEDURE
1. Connections are made as per the circuit diagram.
2. A fixed supply voltage is applied using RPS.
3. Vary the load resistance (RL) and note down the corresponding voltages and
currents.
4. The Power was calculated by using the current and voltage Value.

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA

 EC 3271 – Circuits Analysis Lab Manual

MODEL GRAPH:

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA

 EC 3271 – Circuits Analysis Lab Manual

RESULT
Thus the Maximum Power transfer theorem is verified theoretically and practically for
the given circuit.

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA

 EC 3271 – Circuits Analysis Lab Manual

CIRCUIT DIAGRAM:

TO FIND VTH : (Circuit I)

TO FIND RTH : (Circuit II)

THEVENIN EQUIVALENT CIRCUIT : (Circuit III)

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 EC 3271 – Circuits Analysis Lab Manual

Ex.No:
VERIFICATION OF THEVEVIN’S THEOREM

AIM
To verify Thevenin’s theorem theoretically and practically for a given circuit
APPARATUS REQUIRED
S.NO APPARATUS RANGE TYPE QTY
1. DC Regulated power supply (0-30)V 1
2. Ammeter (0-50)mA MC 1
3. Ammeter (0-10)mA MC 1
4. Voltmeter (0-10)V MC 1
5. Single dial decade resistance box 4
6. Connecting wires
7. Bread Board 1

STATEMENT
Thevenin’s theorem states that any linear two-terminal circuit can be replaced by an
equivalent circuit consisting of a voltage source VTh in series with a resistor RTh.
PROCEDURE
a) To find VTH
1) Connections are given as per the circuit (1).
2) The Thevenin Voltage is noted for various values of supply voltage and tabulated.
b) To find RTH
1) Connections are modified as shown in the circuit (ii).
2) The Thevenin resistance was measured between the terminal A and B by short
circuit the voltage source.

c) To find IL
1) Connections are modified as shown in the circuit (iii).
2) The load current (IL) is noted for various values of the thevenin voltage and
tabulated.
.

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA

 EC 3271 – Circuits Analysis Lab Manual

TABULATION:

Supply PRACTICAL VALUES THEORITICAL VALUES

S.No voltage
VTH (V) RTH ( Ω) IL (mA) VTH (V) RTH (Ω) IL (mA)
(volts)

CALCULATION:

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 EC 3271 – Circuits Analysis Lab Manual

RESULT
Thus the Thevenin’s theorem is verified theoretically and practically for the given
circuit.

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA

 EC 3271 – Circuits Analysis Lab Manual

CIRCUIT DIAGRAM:

TO FIND IN : (Circuit I)

TO FIND RN : (Circuit II)

NORTON EQUIVALENT CIRCUIT : (Circuit III)

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 EC 3271 – Circuits Analysis Lab Manual

Ex.No:
VERIFICATION OF NORTON’S THEOREM

B) AIM
To verify the Norton’s theorem theoritically and practically for a given circuit
APPARATUS REQUIRED
S.NO APPARATUS RANGE TYPE QTY
1. DC Regulated power supply (0-30)V 1
2. Ammeter (0-50)mA MC 1
3. Ammeter (0-10)mA MC 1
4. Voltmeter (0-10)V MC 1
5. Single dial decade resistance box 4
6. Connecting wires
7 Bread Board 1

STATEMENT
Norton’s theorem states that any linear two-terminal circuit can be replaced by an
equivalent circuit consisting of a current source IN in parallel with a resistor RN.
PROCEDURE
a) To find IN
1. Connections are given as per the circuit(i)
2. The Norton current IN is noted for various values of supply voltage and tabulated.
b) To find RTH
1) Connections are modified as shown in the circuit (ii).
2) The current (IRTH) and voltage (VRTH) are noted for the various values of supply
voltage are tabulated.
3) By using Ohm laws, Norton resistance was calculated.
c) To find IL
1. Connections are modified as shown in the circuit (iii)
2. The Load current (IL) is noted for various values of the supply voltage and
tabulated.

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA

 EC 3271 – Circuits Analysis Lab Manual

3) Norton’s resistance is practically calculated by using the Open circuit voltage and
short circuit current.
TABULATION

Supply PRACTICAL VALUES THEORITICAL VALUES

S.No voltage
IN (mA) RN ( Ω) IL (mA) IN (mA) RN (Ω) IL (mA)
(volts)

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 EC 3271 – Circuits Analysis Lab Manual

RESULT
Thus the Norton’s theorem is verified theoretically and practically for the given
circuit.

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA

 EC 3271 – Circuits Analysis Lab Manual

CIRCUIT DIAGRAM

TABULATION
Time (seconds) Capacitor voltage (volts)

MODEL GRAPH

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 EC 3271 – Circuits Analysis Lab Manual

Ex.No:
TRANSIENT RESPONSE OF RC CIRCUIT

AIM
To analyze and determine the transient response of an RC circuit for dc input
APPARATUS REQUIRED
S.NO APPARATUS RANGE Type QTY
1 DC Regulated power supply (0-30)V - 1
3 Volt meter (0-30)V MC 1
4 Resistor 10K - 1
5 Capacitor 4700 f - 1
6 Connecting wires - - -
THEORY
As the capacitors store energy in the form of an electric field, they tend to act like
small secondary-cell batteries, being able to store and release electrical energy. A fully
discharged capacitor maintains zero volts across its terminals, and a charged capacitor
maintains a steady quantity of voltage across its terminals, just like a battery. When
capacitors are placed in a circuit with other sources of voltage, they will absorb energy from
those sources, just as a secondary-cell battery will become charged as a result of being
connected to a generator. A fully discharged capacitor, having a terminal voltage of zero,
will initially act as a short circuit when attached to a source of voltage, drawing maximum
current as it begins to build a charge. Over a time, the capacitor's terminal voltage rises to
meet the applied voltage from the source, and the current through the capacitor decreases
correspondingly.
Once the capacitor has reached the full voltage of the source, it will stop drawing
current from it, and behave essentially as an open-circuit. When the switch is first closed,
the voltage across the capacitor is zero volts; thus, it first behaves as though it were a short
circuit. Over a time, the capacitor voltage will rise to equal battery voltage, ending in a
condition where the capacitor behaves as an open-circuit.

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 EC 3271 – Circuits Analysis Lab Manual

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA

 EC 3271 – Circuits Analysis Lab Manual

PROCEDURE
CHARGING
1. Connections are made as per the circuit diagram.
2. The power supply is switched ON and the voltage is set to 7 volts.
3. Close the switch to position 1 at time t=0 and observe the voltage across capacitor
for every 5 seconds.
4. Plot a graph between voltage across the capacitor and time.
DISCHARGING
1. Close the switch to position 2 at time t=0. Now the capacitor starts discharging.
2. Observe the voltage across the capacitor and the corresponding time until the
capacitor discharges to zero volts.

RESULT
Thus the transient response of an RC circuit for dc input is determined

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 EC 3271 – Circuits Analysis Lab Manual

CIRCUIT DIAGRAM (Series RLC circuit)

TABULATION

Input current Ii=

Frequency
Output current (Io) Gain=20log(I0/Ii)
S.No In
in mA in dB
Hz

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 EC 3271 – Circuits Analysis Lab Manual

Ex.No:
FREQUENCY RESPONSE OF SERIES RESONANCE CIRCUITS

AIM
To determine the resonant frequency and bandwidth of series resonant circuit
APPARATUS REQUIRED
S.NO APPARATUS RANGE TYPE QTY
1 Function Generator 3MHz 1
2 Single dial decade resistance box - 1
3 Single dial decade inductance box - 1
4 Single dial decade capacitance box - 1
5 Voltmeter (0-10V) MI 1
6 Ammeter (0-10mA) MI 1
7 Connecting wires
8 Bread Board 1

THEORY
Impedance (Z) for a serial RLC circuit is a function of the resistance (R), the
inductive reactance (X ), and the capacitive reactance (X ):
L C

Inductive reactance is a function of the inductance (L) and frequency (f) of the AC voltage:

Capacitive reactance is a function of the capacitance (C) and frequency (f) of the AC
voltage:

If the sum of X and X is zero, then the equation for the resonant frequency in a series
L C

RLC circuit is:

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 EC 3271 – Circuits Analysis Lab Manual

MODEL GRAPH

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 EC 3271 – Circuits Analysis Lab Manual

The resonance frequency (ωo) is the frequency at which the output is in phase with
the input. In other words, at resonance, circuit is operating at unity power factor (purely
resistive circuit). The bandwidth (β) is defined as the range of frequencies for which the
peak amplitude of the response is at least 1√2 times the maximum peak amplitude. The
quality factor (Q) of the resonant circuit recognizes this attribute of frequency selectivity
since it is defined as the ratio of the resonant frequency to the bandwidth. Bandwidth of the
series resonant circuit is defined as:

Quality factor is defined as:

PROCEDURE
1. Make the connections as shown in the circuit diagram.
2. Set the input current (Ii) by using function generator as 2mA.
3. Increase the frequency and note down the corresponding output current (I o).
4. Find the frequency at which the output current Io is maximum (Imax).
5. Calculate 0.707 of the maximum current.
6. Plot Gain (dB) Vs f on semi-log paper.

RESULT
Thus the resonant frequency and bandwidth of series resonant circuits are
determined.

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 EC 3271 – Circuits Analysis Lab Manual

CIRCUIT DIAGRAM

TABULATION

Input voltage Vi=

Frequency
Output voltage (Vo) Gain=20log(V0/Vi)
S.No In
in volts in dB
Hz

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 EC 3271 – Circuits Analysis Lab Manual

Ex.No:
FREQUENCY RESPONSE OF PARALLEL RESONANCE CIRCUITS

AIM
To determine the resonant frequency and bandwidth of a parallel resonant circuit
APPARATUS REQUIRED
S.NO APPARATUS RANGE TYPE QTY
1 Function Generator 3MHz - 1
2 Five dial decade resistance box - - 1
3 Five dial decade inductance box - - 1
4 Five dial decade capacitance box - - 1
5 Voltmeter (0-10)V MI 1
6 Connecting wires - - -
7 Bread Board 1
THEORY
Impedance (Z) for a serial RLC circuit is a function of the resistance (R), the
inductive reactance (X ), and the capacitive reactance (X ):
L C

Inductive reactance is a function of the inductance (L) and frequency (f) of the AC voltage:

Capacitive reactance is a function of the capacitance (C) and frequency (f) of the AC

voltage:

If the sum of X and X is zero, then the equation for the resonant frequency in a series
L C

RLC circuit is:

The resonance frequency (ωo) is the frequency at which the output is in phase with
the input. In other words, at resonance, circuit is operating at unity power factor (purely
resistive circuit). The bandwidth (β) is defined as the range of frequencies for which the
peak amplitude of the response is at least 1√2 times the maximum peak amplitude. The
quality factor (Q) of the resonant circuit recognizes this attribute of frequency selectivity
since it is defined as the ratio of the resonant frequency to the bandwidth. For a parallel
circuit, impedance is:

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 EC 3271 – Circuits Analysis Lab Manual

MODEL GRAPH

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 EC 3271 – Circuits Analysis Lab Manual

Bandwidth of the parallel resonant circuit is defined as:

The quality of the frequency response in parallel resonant circuit is described as:

PROCEDURE
1. Make the connections as shown in the circuit diagram.
2. Set the input current (Vi) by using function generator as 5V.
3. Increase the frequency and note down the corresponding output voltage (V o).
4. Find the frequency at which the output Voltage Vo is maximum (Vmax).
5. Calculate 0.707 of the maximum Voltage.
6. Plot Gain (dB) Vs f on semi-log paper.

RESULT
Thus the resonant frequency and bandwidth of parallel resonant circuits are
determined.

Prepared By: K.Karthikeyan, Teaching Fellow/ECE, UCEA