government polytechnic muzaffarpurgpmuz.bih.nic.in/docs/ecn.pdf · experiment-10 aim: to verify the...

Government Polytechnic Muzaffarpur Name of the Lab: Electrical Circuits & Network Lab

Subject Code: 1620306

Experiment-10

Aim: To verify the superposition theorem for the given circuit.

Apparatus Required:

S No. Apparatus Range Quantity

1 RPS (regulated power supply) (0-30V) 2

2 Ammeter (0-10mA) 1

3 Resistors 1k, 330, 220 3

4 Bread Board -- --

5 Wires -- Required

Statement:

Superposition theorem states that in a linear bilateral network containing more

than one source, the current flowing through the branch is the algebraic sum of the current flowing through that branch when sources are considered one at a time and replacing other sources by their respective internal resistances.

Precautions:

1. Voltage control knob should be kept at minimum position.

2. Current control knob of RPS should be kept at maximum position.

Procedure:

1. Give the connections as per the diagram. 2. Set a particular voltage value using RPS1 and RPS2 & note down the

ammeter reading. 3. Set the same voltage in circuit I using RPS1 alone and short circuit

the terminals and note the ammeter reading. 4. Set the same voltage in RPS2 alone as in circuit I and note down the

ammeter reading. 5. Verify superposition theorem.

Circuit diagram:

CIRCUIT - 1

CIRCUIT - 2

CIRCUIT - 3

TABULAR COLUMN

Theoretical Values RPS Ammeter Reading

1 2 (I) mA

Circuit – 1 10 V 10 V

Practical Values RPS Ammeter Reading

1 2 (I) mA




Model Calculations: Result:

Superposition theorem has been verified theoretically and practically.



Experiment-11

Aim: To verify Thevenin’s theorem and to find the full load current for the given circuit.

Apparatus Required:


1 RPS (regulated power supply) (0-30V) 2

2 Ammeter (0-10mA) 1

3 Resistors 1K, 330 3,1

4 Bread Board -- Required

5 DRB -- 1

Statement: Any linear bilateral, active two terminal networks can be replaced by an

equivalent voltage source (VTH). Thevenin’s voltage or VOC in series with looking pack

resistance RTH.

Precautions:

1. Voltage control knob of RPS should be kept at minimum position. 2. Current control knob of RPS should be kept at maximum position.

Procedure:

1. Connections are given as per the circuit diagram. 2. Set a particular value of voltage using RPS and note down the corresponding

ammeter readings. To find VTH

3. Remove the load resistance and measure the open circuit voltage using multi

meter (VTH).

To find RTH

4. To find the Thevenin’s resistance, remove the RPS and short circuit it and

find the RTH using multi meter.

5. Give the connections for equivalent circuit and set VTH and RTH and note the corresponding ammeter reading.

6. Verify Thevenin’s theorem.

Theoretical and Practical Values

E(V) VTH(V) RTH() IL (mA)

Circuit - I Equivalent Circuit

Theoretical 10

Practical 10

Circuit - 1 : To find load current To find VTH To find RTH

Thevenin’s Equivalent circuit:

Model Calculations:

Result:

Hence the Thevenin’s theorem is verified both practically and theoretically.



Experiment-12

Aim: To verify Norton’s theorem for the given circuit.

Apparatus Required:


1 Ammeter (0-10mA) MC 1

(0-30mA) MC 1

2 Resistors 330, 1K 3,1

3 RPS (0-30V) 2

4 Bread Board -- 1

5 Wires -- Required

Statement: Any linear, bilateral, active two terminal networks can be replaced by an

equivalent current source (IN) in parallel with Norton’s resistance (RN). Precautions:


Procedure:

1. Connections are given as per circuit diagram. 2. Set a particular value in RPS and note down the ammeter readings in the

original circuit.

To Find IN:

3. Remove the load resistance and short circuit the terminals. 4. For the same RPS voltage note down the ammeter readings.

To Find RN:

5. Remove RPS and short circuit the terminal and remove the load and note

down the resistance across the two terminals.

Equivalent Circuit:

6. Set IN and RN and note down the ammeter readings. 7. Verify Norton’s theorem.

To find load current in circuit 1:

To find IN To find RN

Norton’s equivalent circuit

Constant current source

Theoretical and Practical Values

E IN RN IL (mA) (volts) (mA) ()

Circuit - I Equivalent

Circuit

Theoretical 10

Values

Practical 10

Values

Model Calculations: Result:

Norton’s is verified practically and theoretically.



Experiment-13

Aim: To verify maximum power transfer theorem for the given circuit.

Apparatus Required:


1 RPS (0-30V) 1

2 Voltmeter (0-10V) MC 1

3 Resistor 1K, 1.3K, 3 3

4 DRB -- 1

5 Bread Board & wires -- Required

Statement: In a linear, bilateral circuit the maximum power will be transferred to the load

when load resistance is equal to source resistance.

Precautions:


Procedure:

Circuit – I 1. Connections are given as per the diagram and set a particular voltage in RPS.

2. Vary RL and note down the corresponding ammeter and voltmeter reading. 3. Repeat the procedure for different values of RL & Tabulate it.

4. Calculate the power for each value of RL. To find VTH:

5. Remove the load, and determine the open circuit voltage using multi meter

(VTH)

To find RTH:

6. Remove the load and short circuit the voltage source (RPS).

7. Find the looking back resistance (RTH) using multi meter.

Equivalent Circuit:

8. Set VTH using RPS and RTH using DRB and note down the ammeter reading. 9. Calculate the power delivered to the load (RL = RTH)

10. Verify maximum transfer theorem.

Circuit - 1

To find VTH

To find RTH Thevenin’s Equation Circuit

Power VS RL

Circuit – I

S No. RL (Ω) I (mA) V(V) P=VI (watts)

1

2

3

4

5

6

7

8

To find Thevenin’s equivalent circuit:

VTH (V) RTH () IL (mA) P (milli watts)

Theoretical Value

Practical Value

Model Calculations:

Result:

Thus maximum power theorem is verified both practically and theoretically.



Experiment-14

Aim: To determine the resonant frequency, self-inductance and the quality factor of the coil in the series and parallel circuits.

Apparatus required:

i. Audio frequency oscillator

ii. Inductance coil

iii. Capacitance box

iv. Resistance box

v. Milliammeter

vi. Multi meter

Theory:

A coil of self-inductance ‘L’ is connected in series with a capacitance ‘C’ and a resistance ‘R’.

This circuit is called as a series LCR circuit. If Vi is the driving voltage a current I will flow in the

circuit. At an angular frequency ωo of the ac source, the current ‘I’ will be in phase with the

voltage V. This condition is called as resonance and the circuit is referred to as a series resonant

circuit. If the inductance ‘L’ is connected in parallel with the capacitance ‘C’ and a resistance ‘R’,

the circuit is known as a parallel LCR circuit.

Formula:

Where is the angular frequency in Hz.

L is the inductance of the coil in H.

C is the capacitance of the capacitor in µF.

R is the resistance of the resistor in Ω.

fr is the resonant frequency of the series and parallel circuit in Hz.

Q is the quality factor of the coil.

Procedure:

Series resonant circuit:

i. The capacitance (C), inductance (L), resistance (R) and a milliammeter (mA) are

connected in series with an AFO.

ii. The capacitance (C) is set to be 0.1 μF and resistance (R) is set as 50 ohms.

iii. The audio frequency oscillator is adjusted to a minimum value of 1 kHz.

iv. The current shown by milliammeter is noted.

v. Keeping the C and R values as a constant, the frequency of AFO is increased in steps of

500 Hz and the corresponding milliammeter readings are noted.

vi. The same procedure is repeated for R = 100, R = 150 and R = 200 ohms, for the same

range of frequency and the readings are tabulated.

vii. A graph is drawn with frequency along the X-axis and the current along the Y-axis. The

frequency, at which the current is maximum, is the resonant frequency.

Circuit diagram:

Graph:

Observation table for resonant frequency in series resonant circuit:

S No Frequency(Hz) Current(mA)

Parallel resonant circuit:

Procedure:

i. The inductance (L), resistance (R), are connected in series, and this is connected in parallel

to the capacitor (C).

ii. The milliammeter (mA) and AFO are connected as shown below.

iii. The capacitance (C) is set to be 0.1 μF and the resistance (R) is set to be 50 ohms.

iv. The audio frequency oscillator is adjusted for a minimum value of f = 1 kHz.

v. The current in the circuit shown by the milliammeter is noted.

vi. Keeping the C and R values to be constant, the frequency is increased in steps of 500 Hz

and the milliammeter readings are noted.

vii. The resistance of the inductance coil (r) is measured using a multi meter.

viii. The procedure is repeated for R values of 100, 150 and 200 ohms for the same range of

frequency and readings are tabulated.

ix. A graph is drawn with the frequency along the X-axis and the current along the Y-axis.

The frequency, at which the current is minimum, is the resonant frequency.

Observation table for resonant frequency in parallel resonant circuit:

S No Frequency(Hz) Current(mA)

Graph:

Result:

For a series resonant circuit:

The resonant frequency is …….. Hz.

The inductance of the coil was found to be ……… mH.

Quality factor was calculated to be ………..

For a parallel resonant circuit:

The resonant frequency is ……… Hz.

The inductance of the coil was found to be ………… mH.

Quality factor was calculated to be ……….

government polytechnic muzaffarpurgpmuz.bih.nic.in/docs/ecn.pdf · experiment-10 aim: to verify the...

Documents