ee6211 electric circuit lab-manual.pdf

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

LABORATORY MANUAL

EE6211 / ELECTRICAL CIRCUITS LABORATORY

(II- SEMESTER EEE)

www.Vidyarthiplus.com

Anna University , Chennai



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REGULATION R-2013

EE6211 - ELECTRICAL CIRCUITS LAB

LIST OF EXPERIMENTS (SYLLABUS )

LIST OF EXPERIMENTS

1. Experimental verification of Kirchhoff’s voltage and current laws

2. Experimental verification of network theorems (Thevenin, Norton, Superposition and maximum power transfer Theorem).

3. Study of CRO and measurement of sinusoidal voltage, frequency and power factor.

4. Experimental determination of time constant of series R-C electric circuits.

5. Experimental determination of frequency response of RLC circuits.

6. Design and Simulation of series resonance circuit.

7. Design and Simulation of parallel resonant circuits.

8. Simulation of low pass and high pass passive filters.

9. Simulation of three phases balanced and unbalanced star, delta networks circuits.

10. Experimental determination of power in three phase circuits by two-watt meter method.

11. Calibration of single phase energy meter.

12. Determination of two port network parameters.



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INDEX

S.NO DATE NAME OF EXPERIMENT Page No

Marks Signature

1 Verification of ohm’s & kirchoff’s law. 3

2 Verification of Thevenin’s and Norton theorem. 15

3 Verification of reciprocity theorem. 27

4 Verification of superposition theorem. 31

5 Maximum power transfer theorem. 37

6 Transient Response of RC Circuits for DC input 41

7 Frequency response of series & Parallel

resonance circuit. 47

8 Design and Simulation of series resonance

circuit 57

9 Design and Simulation of parallel resonant

circuits 63

10 Simulation of low pass and high pass passive

filters 67

11 Simulation of three phases balanced and

unbalanced star, delta networks circuits. 71

12 Experimental determination of power in three

phase circuits by two-watt meter method 79

13 Calibration of single phase energy meter. 83

14 Determination of two port network parameters 87

15 Study of CRO and measurement of sinusoidal

voltage, frequency and power factor 93



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Circuit Diagram:

OHM'S Law

S.No. Voltage Current Resistance

1

2

3

4

5

FOEMULAE USED:

V=IR

WHERE V - VOLTAGE

I- CURRENT

R-RESISTANCE



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EXP.NO: 1

DATE:

VERIFICATION OF OHM’S LAW, KVL AND KCL

(a) VERIFICATION OF OHM’S LAW

AIM

To verify the ohm’s law for the given electrical circuit

APPARATUS REQUIRED

Statement:

Ohm’s law: Ohm’s law states that “ At constant temperature, the steady current flowing

through the conductor is directly proportional to the potential difference across the two ends

of the conductor”.

Procedure:-

1. Connections are made as per the circuit diagram

2. By Varying the Input Voltage , the voltage and the corresponding current values

are noted down for the given Resistor.

Sl. No

Name of the apparatus Range Type Quantity

1 Regulated power supply (0 - 30) V Analog 1

2 Voltmeter (0 - 30) V MC 4

3 Resistor 1 kΩ, 1 W - 3

4 Bread board - - 1

5 Connecting wires - - As Required



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3. Repeat the same procedure for different values of Resistors.



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THEORETICAL CALCULATION:



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RESULT:

Thus Ohm’s law has been verified.



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CIRCUIT DIAGRAM:

TABULAR COLUMN:-

S.No Voltage

(V)

Voltage

V1 (V)

Voltage V2

(V)

Voltage V3

(V)

Total voltage

Vt = V1+V2+V3 (V)

Theoretical Practical

V

V V V

(0 - 30V)

+

-

+ - + - + - (0-30V) (0-30V) (0-30V)

+

- (0-30V)

1k 1k 1k R1 R2 R3



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(b) VERIFICATION OF KIRCHOFF’S VOLTAGE LAW

AIM

To verify the kirchoff’s voltage law for the given electrical circuit

APPARATUS REQUIRED

Sl. No




3 Resistor 1 kΩ, 1 W - 3

4 Bread board - - 1


KIRCHOFF’S VOLTAGE LAW

In any closed circuit the sum of potential drop is equal to the sum potential rise.

PROCEDURE

1. Make the connections as per the circuit diagram

2. Switch on the power supply

3. Vary the RPS to a specified voltage and note down the corresponding voltage

readings across resistors

4. Repeat the above step for various RPS voltages and tabulate the readings




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RESULT:

Thus Kirchoff’s voltage law has been verified.



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CIRCUIT DIAGRAM:

TABULAR COLUMN:-

S.No Current I1

(mA)

Current I2

(mA)

Current I3

(mA)

Current – I1= I2 + I3

Theoretical practical

A

A

A

V RPS

+

-

(0-30V)

+ - + -

+

-

(0-20mA)

(0-20mA)

(0-20mA) R1 = 1k

R2 = 1k

R3 = 1k

+

- (0-30V)



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(c) VERIFICATION OF KIRCHOFF’S CURRENT LAW

AIM:

To verify Kirchoff’s current law for the given circuit

APPARATUS REQUIRED:

KIRCHOFF’S CURRENT LAW

The algebraic sum of the current meeting at any junction or node is zero. In other words, the sum of the current flowing towards a junction is equal to the sum of the current leaving the junction.

PROCEDURE:



3. Vary the RPS to a specified voltage and note down the corresponding ammeter

readings

4. Repeat the above step for various RPS voltages and tabulate the readings

Sl. No




3 Ammeter (0 - 20) mA MC 3

4 Resistor 1 kΩ,1 W - 3

5 Bread board - - 1




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RESULT:

Thus the Kirchoff’s current law has been verified.

-



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CIRCUIT DIAGRAM 1:

CIRCUIT DIAGRAM 2:

DETERMINATION OF THEVENIN VOLTAGE (Vth)

CIRCUIT DIAGRAM 3:

DETERMINATION OF LOAD CURRENT (IL)

RPS (0-30V)

R1 = 1k

R2 = 1k

R3 = 1k

RL= 1k

R1 = 1k

R2 = 1k

R3 = 1k

RPS (0-30V)

V

+

- (0-30V)

RPS (0-30V)

R1= 1k

R2= 1k

R3= 1k

RL= 1k

A (0-20mA)

+

-

+

-



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EXP.NO : 2

DATE :

VERIFICATION OF THEVENIN AND NORTON THEOREM

(i) VERIFICATION OF THEVENIN THEOREM

AIM

To verify the Thevenin theorem for the given electrical circuit

APPARATUS REQUIRED

THEVENIN’S THEOREM

Any linear active network with output terminal A and B can be replaced by an equivalent circuit with a single voltage source Vth (thevenin’s voltage) in series with Rth (thevenin’s resistance)

Vth - open circuit voltage across terminal A & B

Rth – equivalent resistance obtained by looking back the circuit through the open circuit terminal A and B

THEORETICAL CALCULATION

Thevenin’s voltage, Vth = V [R2 / (R 1 + R 2)] Volts

Sl. No





4 Resistor 1 kΩ - 4

5 Bread board - - -

6 Connecting wires - - Required



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CIRCUIT DIAGRAM 4:

DETERMINATION OF Rth

CIRCUIT DIAGRAM 5:

THEVENIN EQUIVALENT CIRCUIT:

R1 = 1k

R2 = 1k

R3 = 1k

Rth

DRB Rth

RL = 1k

RPS

Vth



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PROCEDURE:

To determine Thevenin’s voltage, Vth

1. Make the connections as per the circuit diagram 2. Switch on the power supply 3. Vary the regulated power supply to a specified voltage and note down the

corresponding voltmeter readings 4. Repeat the previous step for different voltage by varying the RPS. 5. Switch off the power supply

To determine of load current, IL

1. Make the connections as per the circuit diagram 2. Switch on the power supply 3. Vary the regulated power supply to a specified voltage and note down the

corresponding ammeter readings 4. Repeat the previous step for different voltage by varying the RPS. 5. Switch off the power supply



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TABULAR COLUMN:-

S.No Voltage (V)

Thevenin’s Voltage (VTh)

Load current (IL)

Practical (V)

Theoretical (V)

Practical (I)

Theoretical (I)




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RESULT:

Thus the Thevenin’s theorem was verified for the given electrical circuit.

Theoretical: Vth = Rth = IL =

Practical: Vth = Rth = IL =



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CIRCUIT DIAGRAM

CIRCUIT DIAGRAM :


DETERMINATION OF (IL)

EQUIVALENT CIRCUIT:

RPS (0-30V)

R1= 1k

R2= 1k

R3= 1k

RL= 1k

R1 = 1k

R2 = 1k

R3 = 1k

Rth

RPS (0-30V)

R1 = 1k

R2= 1k

R3 = 1k

RL= 1k

A (0-20mA)

+

-

+

-

+

- RL = 1k Rth

Isc



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VERIFICATION OF NORTON THEOREM

AIM:

To verify the Norton theorem for the given electrical circuit.

APPARATUS REQUIRED

Sl. No Name of the apparatus Range Type Quantity




4 Resistor 1 kΩ - 4

5 Bread board - - -


NORTON THEOREM

Any linear active network with output terminals A & B can be replaced by an equivalent circuit with a single current source I in parallel with Rth ( Thevenin equivalent resistance)

Where Rth is the equivalent resistance obtained by looking back the circuit through the open terminal A & B

FORMULAE

IL = ISC * ( Rth / (Rth + RL))

where,ISC - Norton equivalent current source in amperes

IL - Current through the load in amperes

Rth - Thevenin’s equivalent resistance in ohms

RL - Load resistance in ohms



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TABULAR COLUMN:-

S.No Voltage (V)

Isc Load current (IL)

Practical (mA)

Theoretical (mA)

Practical (mA)

Theoretical (mA)

VL = IL * RL



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PL = IL2 * RL

PROCEDURE :

1. The connections are given as per the circuit diagram


3. The current in short circuited branch is noted using the ammeter

4. Tabulate the readings and check with the theoretical values

Determination of load current



3. Vary the RPS to a specified voltage and note the corresponding ammeter reading

4. Repeat the above step for various RPS voltages and tabulate the reading




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RESULT

Thus Norton theorem was verified for the given electrical circuit.

Theoretical: Isc = Rth = IL = Practical: Isc = Rth = IL =



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CIRCUIT DIAGRAM 1:

CIRCUIT DIAGRAM 2:

CASE A:

CIRCUIT DIAGRAM 3:

CASE B:

RPS (0-30V)

R1= 1k

R2= 1k

R3= 1k

RL= 1k

R2 = 1k RPS

R1 = 1k R3 = 1k

(0-30V) A

+

- (0-10mA)

+

-

R1 = 1k

R2 = 1k

R3 = 1k

RPS (0-30V)

A

+

- (0-10mA)

+

-



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EXP.NO :3

DATE :

VERIFICATION OF RECIPROCITY THEOREM

AIM:

To practically verify the reciprocity theorem for the network with the theoretical calculation.

APPARATUS REQUIRED:

S.NO Components Type / Range Quantity

1

2

3

4

5

Regulated power supply

Resistor

Ammeter

Bread board

Wires

(0-30)V

1k

MC (0-30)mA

1

1

1

1

THEORY:

In any linear bilateral network the ratio of voltage to current response, in any element to the input is constant even when the position of the input and output are interchanged.

PROCEDURE:

1. Connections are made as per the circuit diagram.

2. Note down the ammeter reading and find the ratio of output current and input

voltage.

3. Interchange the position of ammeter and voltage source.

4. Note down the ammeter reading and find the ratio of output and input voltage.

5. Compare this value with the value obtained in step – 2.



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TABULAR COLUMN:-

S.No Voltage (V)

Case A Case B

Voltage V1 (V)

Current

I2 (mA) Voltage V2 (V)

Current I1

(mA)




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RESULT:

The reciprocity theorem was verified for given network with the theoretical calculation.



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CIRCUIT DIAGRAM 1:

CASE 1: When both voltage sources E1 and E2 are present

CIRCUIT DIAGRAM 2:

CASE 2: When voltage source E1 is present

CIRCUIT DIAGRAM 3: CASE 3: When voltage source E2 is present

RPS

R1 = 1k R3 = 1k

(0-30V) +

-

RL= 1k

A (0-20mA)

+

-

(0-30V) +

-

RPS

R1 = 1k R3 = 1k

(0-30V) RPS

+

-

RL= 1k

A (0-20mA)

+

-

(0-30V) RPS

+

-

R1 = 1k R3 = 1k

RL= 1k

A (0-20mA) +

-



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EXP.NO: 4

DATE:

VERIFICATION OF SUPERPOSITION THEOREM

AIM:

To practically verify superposition theorem for the given network with the theoretical calculation.

APPARATUS REQUIRED:

THEORY:

In a linear bilateral active network containing more than one source the total response obtained is algebraic sum of response obtained individually considering only one source at a time the source being suitable suppressed.

PROCEDURE:

1. The connection is made as per the circuit diagram.

2. With V1 = 20V and V2 = 0V observe the ammeter reading.

3. The above procedure repeated with V1 = 0V and V2 = 20V.

4. The total response at the required terminal is obtained using sum of individual

response.

5. Respect same procedure for different values of V1 and V2.

S. No Components Type/Range Qty

1.

2.

4.

5.

6.

Regulated supply

Resister

Ammeter

Bread board

Wires

(0 - 30)V

1kΩ

(0-20mA)

1

1

2

1

As Required



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TABULAR COLUMN:-

CASE 1: When both voltage sources E1 and E2 are present.

S.No Voltage E1 (V) Voltage E2 (V) Current I

Practical (I) Theoretical (I)

TABULAR COLUMN:-

CASE 2: When voltage source E1 is present. [Circuit Diagram 2]

S.No Voltage E1 (V) Current I




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TABULAR COLUMN:-

CASE 3: When voltage source E1 is present. [Circuit Diagram 3]

S.No Voltage E2 (V) Current I





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RESULT:

Thus superposition theorem was verified theoretically and experimentally.



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CIRCUIT DIAGRAM 1:

CIRCUIT DIAGRAM 2:

DETERMINATION OF THEVENIN VOLTAGE (Vth)

CIRCUIT DIAGRAM 3:


EXP.NO : 5

RPS (0-30V)

R1= 1k

R2= 1k

R3= 1k

RL= 1k

R1 = 1k

R2 = 1k

R3 = 1k

RPS (0-30V)

V

+

- (0-30V)

RPS (0-30V)

R1= 1k

R2= 1k

R3= 1k

Rth



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DATE :

VERIFICATION OF MAXIMUM POWER TRANSFER THEOREM

AIM:

To verify the maximum power transformation in purely passive circuit and the load resistance is variable.

APPARATUS REQUIRED:

S.No

Components Type / Range Quantity

1

2

3

4

Resistor

voltmeter

RPS

1k

(0-30V)MC

(0-30V)

4 No’s

1

1

THEORY:

Maximum power will be delivered from a voltage source to a load, if load resistance is

equal to the internal resistance of the sources.

PROCEDURE:

1. Connections are made as per the circuit diagram.

2. Remove the load resistor on the network

3. Calculated RTH by substituting all sources with their internal resistances

looking back at the network.

4. Calculate VTH, the open circuit voltage between the terminals by replacing all

the sources to their original position.



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FORMULAE:

wattsRV

PowerMaximumL

2th

Where Vth - Thevenin voltage

RL-Load resistor

TABULAR COLUMN:-

S.No Voltage (V)

Thevenin’s voltage Vth Maximum power

delivered=[Vth2/RL]Watts Practical

Voltage Theoretical Voltage




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RESULT:

Thus the maximum power transfer theorem was verified theoretically and experimentally.



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RC – Transients :-

S. No. T(ms) V (t) Amps.

1

2

3

4

5

V



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Ex No. : 06

Date :

TRANSIENT RESPONSE OF RL AND RC CIRCUITS FOR DC INPUT

AIM:

To obtain the transient response of RL and RC circuits for dc input

APPARATUS REQUIRED:

S. No. Components Type/Range Qty.

1

2

3

4

5

6

Regulated power supply

SPST (single pole – single throw switch)

Resistor

Capacitor

Stop watch

DPST

( 0-15 )V

100 Ω

0.01 µF

2 Nos.

1 No

2 No

1 No

1 No

1 No

THEORY:

Electrical devices are controlled by switches which are closed to connect supply to the

device, or opened in order to disconnect the supply to the device. The switching operation

will change the current and voltage in the device. The purely resistive devices will allow

instantaneous change in current and voltage.

An inductive device will not allow sudden change in current and capacitance device

will not allow sudden change in voltage. Hence when switching operation is performed in

inductive and capacitive devices, the current & voltage in device will take a certain time to

change from pre switching value to steady state value after switching. This phenomenon is

known as transient.

The study of switching condition in the circuit is called transient analysis.The state of the circuit from instant of switching to attainment of steady state is called transient state. The



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time duration from the instant of switching till the steady state is called transient period. The

current & voltage of circuit elements during transient period is called transient response.

PROCEDURE:

1. Charge on capacitor is ‘o’ initially.

2. If there is a charge in it, short circuit the terminal then the charge will be dissipated.

3. Close the switch at t = 0

4. Simultaneously switch on the stop watch.

5. For every 2 seconds note down the voltage across capacitor until

Voltmeter reaches 5 V.After reaching 15V allow 10 sec. for it.

THEORETICAL VERIFICATION:

R-L Circuit:

V. = Ri + Ldtdi

S15 = R I(S) + L S I(s)

R-C Circuit;

V. = Ri + idtC1

S15 = I (s)

s

810100



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RESULT:

Thus, the transient response of RC circuits for dc input was obtained .



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CIRCUIT DIAGRAM

TABULAR COLUMN:- Input voltage, Vin

= …………..V

S.No Frequency (Hz) Voltage (Vo) Voltage Gain

= 20 log V0/Vin

250mH 1F

1k (0-30)MHz ~ FG CRO



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Ex No. :07

Date :

FREQUENCY RESPONSE OF SERIES AND PARALLEL RESONANCE CIRCUITS

(a) FREQUENCY RESPONSE OF SERIES RLC CIRCUIT

AIM

To determine and obtain the frequency response of a series RLC circuit

APPARATUS REQUIRED


1 Decade Resistance Box 1 kΩ - 1

2 Decade Inductance Box 250 mH - 1

3 Decade Capacitance Box 1 μF - 1

4 Function Generator (0 - 3) MHz - 1

5 C.R.O. - Analog 1

6 Bread Board - - 1


THEORY

An A.C. circuit is said to be in resonance with its power factor becomes unity at which the impedance of circuit becomes purely resistive. The frequency at which such condition occurs is called resonant frequency. At resonance the circuit current is maximum for series resonant.

FORMULAE

Resonant frequency, F0 = 1 / [ 2π √LC ]

Band width = F2 – F1

Quality factor = W0 L / R Where, F0 – Resonant frequency



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Model graph:

F1 – Lower cut off frequency in Hz

F2 – Upper cut off frequency in Hz



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PROCEDURE:


2. Set the values of R, L & C

3. Frequency varied from 1kHz to 100 kHz in steps

4. At each step the frequency and voltage is noted down

5. Graph is drawn between frequency along X – axis and voltage along Y – axis



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RESULT:

Thus the frequency response of series resonant circuit was obtained



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CIRCUIT DIAGRAM

TABULAR COLUMN:- Input voltage, Vin

= …………..V

S.No Frequency (Hz) Voltage (Vo) Voltage Gain

= 20 log V0/Vin

~ 1k CRO FG (0-30)MHz

1F

250mH



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(B) FREQUENCY RESPONSE OF PARALLEL RLC CIRCUIT

AIM

To determine and obtain the frequency response of parallel R L C circuit

APPARATUS REQUIRED


1 Decade Resistance Box 1 kΩ - 1

2 Decade Inductance Box 250 mH - 1

3 Decade Capacitance Box 2 μF - 1

4 Function Generator (0 - 3) MHz - 1

5 C.R.O. - Analog 1

6 Bread Board - - 1


THEORY

An A.C. circuit is said to be in resonance when its power factor becomes unity. The impedance of circuit at resonance becomes purely resistive. The frequency at which such a condition occurs is called resonant frequency.

The impedance is given by Z = R + j (XL - XC)

When the impedance is real, the | Z | is minimum. At resonance the power factor is unity

Therefore, Z = R and reactive part is zero. Thus XL - XC = 0

ω0 = 1 / √LC

f0 = 1 / 2π √LC



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MODEL GRAPH:




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FORMULAE USED:

Resonant frequency, f0 = 1 / 2π √LC

Band width = F2 – F1

Quality factor = ω0L / R

Where,

f0 – Resonant frequency in Hz

F1 – Lower cut off frequency in Hz

F2 – Upper cut off frequency in Hz

PROCEDURE


2. Set the values of R, L & C

3. Frequency varied from 1kHz to 100 kHz in steps

4. At each step the frequency and voltage is noted down

5. Graph is drawn between frequency along X – axis and voltage along Y – axis

RESULT

The frequency response of a parallel R.L.C. circuit was obtained.



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SIMULATION DIAGRAM



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EXP.NO: 08

DATE:

DESIGN AND SIMULATION OF SERIES RESONANCE CIRCUIT

AIM

To design and simulation of series resonance circuit using pspice and matlab

SOFTWARE REQUIRED

Orcad-Pspice

Matlab

PROCEDURE

Pspice

1. Build the schematic shown in Figure 1.

2. Vm is an AC voltage source (VAC) from the source library. It needs to be set for 1 volt.

3. L1 is an ideal inductor from the Analog Library. Set for 1000mH.

4. R is an ideal resistor from the Analog Library. Set value to Rx. Next add part named

“Parameters”. Then double click on part to enter edit mode. Click on new column, name = Rx, value

= 200. Then click on column, select display and click on name and value.

5. C1 is an ideal capacitor from the Analog library. Change the value to 40pF.

PSPICE SIMULATION PROFILE SETTINGS

1. Do analysis setup

a. At top of screen click on Pspice

b. Click on New Simulations Profile

c. Type name of profile that you wish.

d. Under Analysis tab, select AC sweep from the Analysis type pull down menu.

e. Under AC Sweep Type



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Fig. a

Fig.b

Fig.(a)&(b) Result of input impedance of series RLC tank circuit



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2.Select Logarithmic and Decade as shown.

i. Start freq = 100

ii. End freq = 10Meg

iii. Points/Decade = 101

f. Then click the run Pspice button. (Looks like a play button)

g. After running, look at schematic file and click on trace, add trace.

h. Next Select Db() on left, select M() on left, select V(Vm:+), then divide by M(I(Vm)).

3. Use the same circuit as above, and from the Pspice button, Markers, Advanced, select “db magnitude of

current marker” and “Phase of Current marker”, and place in series next to L1.

Fig. Simulation Profile Settings



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Fig. Series Resonance Circuit



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MATLAB Input impedance of series RLC tank circuit

disp('starting the function of Zinput_seriesRLC1'); %define all the component values and units for Tank Vm=1; %volts R=200; %ohms C=40e-12; %Farads L=1000e-6; %Henrys %define the input impedance Zin_numb=[L*C R*C 1]; Zin_de=[0 C 0]; Zinput=tf(Zin_numb,Zin_de) figure(1) bode(Zinput) title('Input impedance of series RLC tank circuit') %calculating important parameters of the tank [z,p,k]=zpkdata(Zinput,'v'); wo=sqrt(1/L/C) Beta=R/L Q=wo/Beta disp(' finished the function of Zinput_seriesRLC1'); Result Thus the series resonance circuit was designed and simulated using Pspice and Matlab



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Pspice Simulation Diagram of Parallel Resonant Circuit

Output



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EXP.NO:09

DATE:

DESIGN AND SIMULATION OF PARALLEL RESONANCE CIRCUIT

AIM

To design and simulation of parallel resonance circuit using orcad - Pspice and Matlab

SOFTWARE REQUIRED

Orcad-Pspice

PROCEDURE

Pspice

1. Build the schematic shown in Figure 1. 2. Apply the IAC, because we want to plot the frequency response 3. Set ACMAG =0.001 in IAC 4. L1 is an ideal inductor from the Analog Library. Set for 1H. 5. R is an ideal resistor from the Analog Library. Set value to Rx. Next add part named

“Parameters”. Then double click on part to enter edit mode. Click on new column, name = Rx, value = 200. Then click on column, select display and click on name and value.

6. C1 is an ideal capacitor from the Analog library. Change the value to 100nF.


1. Do analysis setup a. On the ORCAD Capture CISÒ menu select new simulation profile b. Choose AC Sweep/Noise in the Analysis type menu c. Set the Start Frequency at 100, the End Frequency at 10Meg and the Points/Decade at 101 d. Make sure Logarithmic is selected and set to Decade e. Click OK

2. Use the same circuit as above and place the “db magnitude of voltage marker” and the “phase of voltage marker” in series next to output capacitor.



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Fig. Matlab output for input impedance for parallel resonance circuit



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MATLAB Input impedance of Parallel RLC tank circuit function [Zinput]=Zinput_parallelRLC1() disp('Starting the function of Zinput_seriesRLC1'); Im =0.0001; R=20000; C=100e-09; L=0.1; Zinductor=tf([L 0],[0,1]); Zcapacitor=tf([0 1], [C 0]); Zinput=1/(1/R+1/Zcapacitor+1/Zinductor) figure(1) bode(Zinput) title('Input impedance of parallel RLC tank circuit') [z,p,k]=zpkdata(Zinput,'v'); w0=sqrt(1/L/C) Beta=1/R/C Q=w0/Beta disp('finished the function of Zinput_seriesRLC1'); Result Thus the parallel resonance circuit was designed and simulated using Pspice and Matlab



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Fig.1.a.Circuit diagram

Fig.1.b.Output for above circuit

Fig.1.Low Pass Passive Filter



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EXP.NO:10

DATE:

SIMULATION OF LOW PASS AND HIGH PASS PASSIVE FILTERS

AIM

To design and simulation of low pass and high passive filter using P-spice SOFTWARE REQUIRED

Orcad Pspice

PROCEDURE

(a) Low Pass Passive Filter

Pspice

1. Build the schematic shown in Figure 1. 2. Apply the VAC, set VAC to 1. 3. R is an ideal resistor from the Analog Library. Set value to 1k 4. C is an ideal capacitor from the Analog library. Change the value to 0.1u.

This is a classical low pass filter with RC cut off frequency (-3db) that can be estimated by the formula fc= (6.28*R*C), and in our case fc=1 / (6.28*0.1*1k)=1.59khz, where we express the capacitances in uF, resistance in kohm and frequency in khz


1. Do analysis setup a. On the ORCAD Capture CISÒ menu select new simulation profile b. Choose AC Sweep/Noise in the Analysis type menu c. Set the Start Frequency at 10, the End Frequency at 1Meg and the Points/Decade at 10 d. Make sure Logarithmic is selected and set to Decade e. Click OK

2. Use the same circuit as above and place the “voltage marker” and the “db of voltage marker”



75

Fig.2.a.Circuit diagram

Fig.2.b.Output for above circuit

Fig2 .High Pass Passive Filter



76

High Pass Passive Filter

Pspice

1. Build the schematic shown in Figure 1. 2. Apply the VAC, set VAC to 1. 3. R is an ideal resistor from the Analog Library. Set value to 1k 4. C is an ideal capacitor from the Analog library. Change the value to 0.1u.

This is a classical low pass filter with RC cut off frequency (-3db) that can be estimated by the formula fc= (6.28*R*C), and in our case fc=1 / (6.28*0.1*1k)=1.59khz, where we express the capacitances in uF, resistance in kohm and frequency in khz

Result Thus the passive low pass and high pass filter was designed and simulated using Pspice .



77

Fig. Three-Phase Circuits with Line and Load Impedances

Fig. Pspice circuit for Three-Phase Circuits with Line and Load Impedances



78

EXP.NO:11

DATE:

SIMULATION OF THREE PHASES BALANCED AND UNBALANCED STAR, DELTA NETWORKS CIRCUITS

AIM

To build, simulate, and analyze three-phase circuits using OrCAD Capture Pspice Schematics under balanced and unbalanced conditions, and to understand the characteristic of 3-phase power transmission circuits SOFTWARE REQUIRED

Orcad Pspice

Problem:

1 .In Fig, let’s assume that the three-phase circuits are balanced and each has a magnitude (peak value) of

170 V at 60Hz in the positive sequence with Va = 170 V 00 . The line impedance is (1 + j10) Ω, and the

load is (20 + j20). Find: a) the line currents (Ia, Ib, Ic) and the neutral current (In) in peak values b) the power

loss in each line, including the neutral c) the power factor for each phase of the load

2. Repeat problem for given figure, but let’s now assume that the three-phase circuits are unbalanced and

operating in the positive sequence with Va = 170 V 00 . Use the same line impedance, but the load is now

(20 + j20) Ω for phase A, (50 + j10) Ω for phase B, and (5 + j50) for phase c.

Procedure 1. Three-Phase Balanced Circuits

a. Build the three-phase circuits of Figure 1 onto the Schematic window

b. To get parts, click button on the right hand side menu. Alternatively, you could also get parts by going to

the top menu, click on Place, and then select “Part”.

c. If no library is shown on the Place Part window, then you will have to manually add the library by

clicking the “Add Library” button. Look for a library called “Source” and click on it. The “SOURCE”

library should now be listed on the “Place Part” window.

d. The three-phase voltages are made up of three ac sinusoidal single-phase voltage sources “Vsin” under

the “SOURCE” library to build the three-phase voltages. Once the Vsin part is on the schematic, double

click on it to assign its parameter values:



79

Simulation Setting window



80

AC=0 DC=0 FREQ=60 PHASE=0 VAMPL=170 VOFF=0

Note that the other two Vsin voltages should have the same parameter values as above except their phases

(for V2 and V3) should be -1200 and + 1200, respectively (assuming the phase sequence is positive).

e. Passive components such as Resistor, Inductor, or Capacitor can be found under the “ANALOG” library.

For the given impedances in the problem 1, determine the resistor and inductor values. These are the

values that you will need to assign for the Resistors and Inductors on the schematic.

f. Connect a “0/ source” ground to the neutral points (node n and N in Figure 1). The ground can be obtained

by clicking on the right side bar menu, and then select “0 /SOURCE” in the “Place Ground” window as

shown in Figure.

g. After the schematic is done, go to “Pspice” on the top menu, and select “New Simulation Profile”. A

window appears asking you to name the simulation profile. Type in any name, but preferably something that

relates to your schematic, such as “three-phase”. Then, hit OK and the following window appears.

j. Enter the following values for the simulation settings and then hit OK: Run to time=1050ms, Start saving

data after=1000ms, Maximum step size=0.1ms Check the box for the “Skip the initial transient bias point

calculation (SKIPBP)”

k. Run Pspice Simulation by selecting “Run” under “Pspice” on the menu. Once the simulation is

completed, a Probe window will appear as shown in Figure. However, if there is an error or more on your

schematic then the simulation will stop. You should then go back to the schematic page and trouble-shoot

the schematic.

l. To show various waveforms (voltage, current, power) from the schematic, go back to the schematic

window and then place the markers or probes to any place of your interest on the schematic. The probes are

located just below the top menu and there are four probes available: voltage (V) , voltage differential (V+V-)

, current (I) and power (W). Note that you should run your simulation again every time you add or remove

probes.

m. To observe the input voltage waveforms, place the Voltage markers on top of each Vsin symbol on your

schematic. This will automatically generate the waveforms on the Probe window. Switch to the Probe

window and you should see the waveforms of balanced three-phase voltages as shown in Figure

n. Remove voltage probes for Phase B and Phase C from the schematic, and add a current probe into Phase

A.



81

Three Phase

voltage waveform

Voltage and current probes or markers on Phase A



82

o. Switch back to the Probe Window, you should now see the Phase A voltage and the line current A as

shown in Figure.

p. Rescale the current waveform by a factor of 10 to see the current waveform more clearly. This is done by

double clicking the name of the current waveform (I(R1) in Figure

r. To determine the times when these zero crossings occur, you may use the cursors by clicking on the menu.

There are two cursors which are movable by the use of left click and right click of your mouse. At this point,

the two cursors should be on one of the waveforms. To find out which waveform the cursors are currently

on, look at the names of the waveforms (bottom left of the plot). If the legend of the waveform is surrounded

by a square then the cursors will be assigned to the waveform. Also, if you look at the bottom right of the

plot, you should also see a small window entitled “Probe Cursor” which shows the location of the cursors (x

and y coordinates) on the plot

s. The “Probe Cursor” window consists of 3 rows and 2 columns. The first column shows the time in ms and

the second column show the voltage in Volts and/or current in Amps. The third row shows the difference

between the two x-points (row 3 column 1) and the two y points (row 3 column 2). See Figure again. t. Use

the right click of your mouse to move one cursor to find the zero crossing of the voltage as shown in Figure.

Use the left hand click to measure the zero crossing of the current. Note that you won’t be able to get exactly

0 for the y points, so do the best you can to get a number close to 0. Ask your instructor to verify your result

and then print it out.

u. From the zero crossing values that you just obtained, measure the power factor as seen by the source, i.e.,

power factor associated with the total impedance of he load and the line. Is it a lagging or leading power

factor?

v. “Zoom to fit” the plot by clicking on the upper right corner of the plot. Delete both waveforms from the

plot, and plot the neutral current by placing the current probe on the neutral line on the schematic. Observe

the value of the neutral current.

w. Delete the neutral current waveform from the plot, and, instead, add the load voltage from phase A to the

plot. Switch to the Probe Window and you should see the load voltage waveform on the plot.



83

Voltage and current after rescaling the current waveform

Figure. Zooming in to the zero crossing points



84

2. Three-Phase Unbalanced Circuits

a. Build a three-phase unbalanced circuit using the same three-phase schematic of part 1. Change the load

impedance to the values listed in Problem 2.

b. Run the simulation and obtain the load voltage waveforms into a single plot. Copy and paste into Word.

Note that because the circuit is unbalanced, the voltage at the load side of the neutral line is not the same as

the voltage at its source side, i.e. at ground level. Hence, to obtain the load voltage waveform, you have to

use the “Differential Voltage” probe or marker from the menu. With this probe, you will have to place two

markers (since it will be measuring a differential voltage): V+ marker and V- marker. Place the V+ marker

with the first click of your mouse

to the top terminal of load resistor R1a and place the V- marker on the bottom terminal of load inductor L1a.

c. Delete the load voltage waveforms and obtain the input voltage waveforms (i.e., the three phase voltages

at the source side) into a single plot. Copy and paste into Word.

d. Remove the input voltage waveforms and now plot the current waveforms (all line currents and neutral

current) into a single plot. Rescale any current waveform if necessary to make all waveforms visible on the

plot. Copy and paste into Word.

e. Determine the power factor for each phase of the load by measuring the phase difference between the

voltage across and the current through it. Note that the phase difference between the voltage across and the

current through each of the three load phases should be equal (theoretically) to the angle of the

corresponding load impedance.

Result

Thus the three phase circuits (balanced or unbalanced, star or delta) are designed and analyzed

using Orcad Pspice software.



85

CIRCUIT DIAGRAM

THREE PHASE POWER AND POWER FACTOR MEASUREMENT



86

EXP. NO. 12

DATE:

MEASUREMENT OF THREE PHASE POWER AND POWER FACTOR

AIM

To conduct a suitable experiment on a 3-phase load connected in star or delta to measure the three phase power and power factor using 2 wattmeter method.

OBJECTIVES

1. To study the working of wattmeter

2. To accurately measure the 3 phase power

3. To accurately measure the power factor

4. To study the concept of star connected load and delta connected load

APPARATUS REQUIRED:

S.NO NAME OF THE APPRATUS RANGE QUANTITY

1 Two element wattmeter (600V,10A,LPF) 1

2 MI Ammeter (0-10)A 1

3. MI voltmeter (0-600)V 1

4. Power Factor meter 1

5. Connecting wires Required FORMULA TO BE USED:

Output power W = W1+W2 in KW

PF = W/(√ Vp Ip)

Let x revolution / kwh be the rating.

Now x revolution = 1 kwh

= 1* 3600*1000 watt-sec.

Constant k of energymeter = 3600 * 103/ x watt-sec

For each load, indicated power Wi is given as Wi = k/t watts



87

TABULAR COLUMN:

S.NO

LOAD CURRENT

I (Amps)

WATTMETER

READING,

Wa (W)

INDICATED

POWER,

Wi (W)

Time taken ,

t (secs)

% ERROR

NOTE:

From the calibration curve it is possible to predict the error in recording the energy. So the correction can be applied to the energy meter reading so that correct energy reading can be obtained and used.

Where



88

K= energy meter constant (watt-sec)

t = time for 1 revolution(sec)

% error = Wi – Wa / Wi * 100

Where Wi is indicated power in watts

Wa is actual power shown by wattmeter in watts

% error can be zero +ve or –ve.

PROCEDURE:

1. Switch ON the 3 phase MCB.

2. Vary the load step by step.

3. For each step note down the wattmeter, voltmeter, ammeter readings.

4. Determine the power using the formula.

RESULT:

The Power and Power factor of the given experiment is measured by using two wattmeter methods.



89

CIRCUIT DIAGRAM

SINGLE PHASE ENERGY METER

TABULAR COLUMN:

S.No

True power KW

No of revolution

Time

True energy kWh

Energy recorded

kWh

% error



90

EXPT. NO.13

DATE:

CALIBRATION OF SINGLE PHASE ENERGYMETER

AIM:

To calibrate the given single phase energy meter at unity and other power factors

OBJECTIVE:

1. To study the working of energy meter.

2. To accurately calibrate the meter at unity and other power factor.

3. To study the % of error for the given energy meter.

APPARATUS REQUIRED:

S.NO NAME OF THE APPRATUS RANGE QUANTITY 1 Single-Phase Energy meter 1

2 Wattmeter (300V,10A LPF) 1

3. Stopwatch 1

4. M.I Ammeter (0-5)A 1

5. M.I Voltmeter (0-300)V 1

6. Connecting wires Required

FORMULA TO BE USED:

1. True energy = W*t

2. Energy Recorded = No of revolution /Energy meter constant.

3. %error = (True energy- Energy recorded)/True energy

CONNECTION PROCEDURE:

1. Connect the main supply to the MCB input.

2. Connect voltmeter, Ammeter, in series and parallel with supply.

3. Connect MCB output phase terminal to main M terminal of wattmeter.

4. Connect Line L signal of wattmeter to energy meter 1S terminal.

5. Connect voltage V of wattmeter to supply neutral terminal.

6. Connect main supply neutral to 2S terminal of Energy meter.

7. Connect 2L,1L terminal of Energy meter to RL load terminal L1,L2.



91

EXPERIMENTAL PROCEDURE:

1. Connections are given as per the circuit diagrams.

2. Switch on the power supply.

3. Vary the load and keep one particular position.

4. Note down the wattmeter readings.

5. Determine the time require to complete the revolution of energy meter.

6. From that find out the actual energy consumed, energy recorded and percentage of error.

THEORY

RESULT:

Thus the given single phase energy meter is calibrated with actual energy consumption and found out the error.



92

Circuit Diagram



93

EXP. NO. 14

DATE:

DETERMINATION OF TWO PORT NETWORK PARAMETERS

AIM

To calculate and verify 'Z' ,‘Y’ , ABCD, and H parameters of two-port network.

APPARATUS REQUIRED

Sl. No.

Name of the component Specifications Quantity

1 Resistors 1K 2 2K 1

2 Regulated Power Supply (RPS) 0-30 V 1 3 Voltmeter 0-20V 1 4 Ammeter 0-20 mA 1 5 Decade Resistance Box (DRB) 10W-1MW 1 6 Bread Board 1 7 Multi meter 1

THEORY: In Z parameters of a two-port, the input & output voltages V1 & V2 can be expressed in terms of input & output currents I1 & I2. Out of four variables (i.e V1, V2, I1, I2) V1& V2 are dependent variables whereas I1 & I2 are independent variables. Thus,

V1 = Z11I1+ Z12 I2 -----(1)

V2 = Z21I1 + Z22 I2 -----(2)

Here Z11 & Z22 are the input & output driving point impedances while Z12 & Z21 are the

reverse & forward transfer impedances.

In Y parameters of a two-port, the input & output currents I1 & I2 can be expressed in terms of input & output

voltages V1 & V2 . Out of four variables (i.e I1, I2, V, V2) I1& I2 are dependent variables whereas V1 & V2 are

independent variables.

I1 = Y11V1 + Y12V2 ------(3)

I2 = Y21V1 + Y22V2 -------(4)

Here Y11 & Y22 are the input & output driving point admittances while Y12 & Y21are the

reverse & forward transfer admittances



94

OBSERVATION TABLE:

Z Parameters

S.No When i/p is open ckt When o/p is open ckt

V2 V1 I2 V2 V1 I1

Y Parameters

S.No When i/p is short ckt When o/p is short ckt

V2 I1 I2 V1 I1 I2

ABCD Parameters

S.No When o/p is short ckt When i/p is short ckt

V1 I1 I2 V2 V1 I2

H Parameters

S.No When o/p is open ckt When o/p is short ckt

V1 V2 I1 V1 I2 I1



95

ABCD parameters are widely used in analysis of power transmission engineering where they are termed as “Circuit

Parameters”. ABCD parameters are also known as “Transmission Parameters”. In these parameters, the voltage &

current at the sending end terminals can be expressed in terms of voltage & current at the receiving end.

Thus,

V1 = AV 2 + B (-I2) ---------(5)

I1 = CV2 + D (-I2) -----------(6)

Here “A” is called reverse voltage ratio, “B” is called transfer impedance “C” is called

transfer admittance & “D” is called reverse current ratio.

In ‘h’ parameters of a two port network, voltage of the input port and the current of the

output port are expressed in terms of the current of the input port and the voltage of the

output port. Due to this reason, these parameters are called as ‘hybrid’ parameters, i.e. out

of four variables (i.e. V1, V2, I1, I2) V1, I2 are dependent variables.

Thus,

V1= h11I1 + h12V2 ------------- (1)

I2 = h21I1 + h22V22 ----------- (2)

H11 and H22 are input impedance and output admittance.

H21 and H12 are forward current gain and reverse voltage gain

PROCEDURE:

Z-Parameter

(1) Connect the circuit as shown in fig. & switch ‘ON’ the experimental board.

(2) First open the O/P terminal & supply 5V to I/P terminal. Measure O/P Voltage & I/P Current.

(3) Secondly, open I/P terminal & supply 5V to O/P terminal. Measure I/P Voltage & O/P current using multi-meter.

(4) Calculate the values of Z parameter using Equation (1) & (2).

(5) Switch ‘OFF’ the supply after taking the readings.



96

SAMPLE CALCULATION:

Z PARAMETER:

(1) When O/P is open circuited i.e. I2 = 0

Z11 = V1/I1 , Z21 =V2 /I1.

(2) When I/P is open circuited i.e. II = 0

Z12 = V1/I2 , Z22 = V2 /I2.

Y PARAMETER:

(1) When O/P is short circuited i.e. V2 = 0

Y11 = I1/V1 Y21 = I2 /V1

(2) When I/P is short circuited i.e. VI = 0

Y12 = I1/V2 Y22 = I2 /V2.

ABCD PARAMETER:

(1)When O/P is open circuited i.e. I2 = 0

A = V1/V2 C = I1 /V2

(2)When O/P is short circuited i.e. V2 = 0

B = -V1/I2 D = -I1 /I2

H PARAMETER:

(1)When O/P is short circuited i.e. V2 = 0

h11 = V1/I1 h21 = I2 /I1

(2)When I/P is open circuited i.e. II = 0

h12 = V1/V2 h22 = I2 /V2



97

Y-Parameter


(2) First short the O/P terminal & supply 5V to I/P terminal. Measure O/P & I/P current

(3) Secondly, short I/P terminal & supply 5V to O/P terminal. Measure I/P & O/P current using multi-meter.

(4) Calculate the values of Y parameter using Eq. (1) & (2).

(5) Switch ‘off’ the supply after taking the readings.

ABCD Parameter


(2) First open the O/P terminal & supply 5V to I/P terminal. Measure O/P voltage & I/P current

(3) Secondly, short the O/P terminal & supply 5V to I/P terminal. Measure I/P & O/P current using multi-meter.

(4) Calculate the A, B, C, & D parameters using the Eq. (1) & (2).


H Parameter


(2) Short the output port and excite input port with a known voltage source Vs. So that V1 = Vs and V2 = 0. We

determine I1 and I2 to obtain h11 and h21.

(3) Input port is open circuited and output port is excited with the same voltage source Vs. So that V2 = VS and I1 =

0, we determine I2 and V1 to obtain h12 and h22.


RESULT:

Thus the various parameters of the two port network has been calculated and verified



98

Fig.1.Basic structure of CRO

Fig.2. Front Panel of CRO\



99

EXP. NO. 15

DATE:

STUDY OF CRO AND MEASUREMENT OF SINUSOIDAL VOLTAGE, FREQUENCY AND POWER FACTOR

Objective

• To introduce the basic structure of a cathode-ray Oscilloscope.

• To get familiar with the use of different control switches of the device.

• To visualize an ac signal, measure the amplitude and the frequency

Theory

Cathode-ray Oscilloscope

fluorescent screen (see Figure 1). When the cathode is heated (by Theory Cathode-ray Oscilloscope applying a small

potential difference across its terminals), it emits electrons. Having a potential difference between the cathode and the

anode (electrodes), accelerate the emitted electrons towards the anode, forming an electron beam, which passes to fall

on the screen. When the fast electron beam strikes the fluorescent screen, a bright visible spot is produced. The grid,

which is situated between the electrodes, controls the amount of electrons passing through it thereby controlling the

intensity of the electron beam. The X&Y-plates, are responsible for deflecting the electron beam horizontally and

vertically.

A sweep generator is connected to the X-plates, which moves the bright spot horizontally across the screen

and repeats that at a certain frequency as the source of the signal. The voltage to be studied is applied to the Y-plates.

The combined sweep and Y voltages produce a graph showing the variation of voltage with time, as shown in Fig. 2.

Alternating current (ac)

An ac signal can be of different forms: sinusoidal, square, or triangular. The sinusoidal is the most popular

type, which is the natural output of the rotary electricity generators. An ac voltage source can be represented by

)sin()( wtt m (1)

where εm is the maximum output voltage value, ω =2πƒ (ƒ is the frequency), and φ is the phase shift.

Table 1



100

Frequency (Hz) Period (T)Sec F(Hz) Vp-p(V) Vrms(V)

200

X

1000

Y

2000

Vrms(multimeter)=

Procedure

Part one

1. Turn on the Oscilloscope, wait a couple of seconds to warm up, then the trace will show up on the screen.

2. Adjust the intensity and the focus of the trace.

3. Use the X &Y-post. knobs to center the trace horizontally and vertically.

4. Connect a cable to Ch1 socket.

5. Turn on the Heath kit.

6. Connect the cable from Ch1 of the CRO to the SIN connector of the Heathkit, via a piece of wire.

7. A signal will appear on the screen.

8. Make sure that the inner red knobs of the Volt/Div and the Time/Div are locked clockwise.

9. Set the frequency of the generator to 200 Hz.

10. Adjust the Volt/Div and the Time/Div knobs so that you get a suitable size signal

(from 1-2 wavelengths filling most of the screen vertically).

11. Count the number of vertical squares lying within the signal, then calculate the peak

to peak value as:

Vp-p= No. vertical Div x Volt/Div

12. Calculate Vrms value, record in Table I:



101

Vrms= Vp-p / 2.sqr root(2)

13. Measure Vrms using the multimeter (connect the probes of the multimeter to the SIN

and the GND connectors).

14. Calculate the period T, record in Table I:

T = No. horizontal Div. × Time/Div

15. Calculate the frequency, ƒ=1/T, record in the table.

16. Repeat steps 10-14 for the frequency values as in the table

Part two

1. Connect the cable from Ch1 to the upper connector of the line frequency of the Heathkit.

2. Adjust the Volt/Div and the Time/Div knobs so that you get a suitable size signal

(from 1-2 wavelengths filling most of the screen vertically).

3. Calculate the peak to peak voltage value.

4. Calculate Vrms value.

5. Measure Vrms using the multimeter.

6. Measure the period T, then calculate the frequency.

Vp-p=

Vrms=

Vrms(multimeter)=

T=

f=

Result

Thus the CRO basic structure, measurement of voltage and frequency was studied.



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