ece department eci lab manual

ECE Department ECI Lab Manual

TABLE OF CONTENTS

ECE Department ECI Lab Manual

VERIFICATION OF OHMS LAW

CIRCUIT DIAGRAM

TABULATIONS.NOVoltage across RV in VoltsCurrent through RI in (mA)Resistance R=V/I in ohm

1. VERIFICATION OF OHMS LAW

Exp.No: Date:..

AIMTo verify the ohms law using standard resistances, Ammeter and voltmeter.

APPARATUS REQUIREDSl. NoApparatus NameRangeTypeQuantity

1RPS 0-30-1

2Ammeter(0-100) mA1

3Voltmeter(0-50)V1

4Resistance1K-1

5Bread board--1

6Connecting wires--As Required

THEORYOHMS LAWThe ratio to potential difference (V) between any two points on a conductor to the current (i) flowing between them is constant, provided the temperature of the conductor does not change.V/I=constant.

FORMULA:V = IRWhere V = Voltage (potential difference) in voltsI = Current in milli AmperesR=Resistance in ohms.

MODEL CALCULATION

PROCEDURE:1. Connections are made as shown in the circuit diagram.2. The voltage is varied in steps and the corresponding current is noted in the tabular column.3. The ratio of voltage (v) and current (I)is calculated

RESULT:Thus the ohms law was verified using standard resistances, ammeter and voltmeter.

KIRCHOFFS CURRENT LAWCIRCUIT DIAGRAM

TABULATIONSl.NOVoltage V in voltsCurrent I in mAI3=I1+I2 mA

I1I2I3

1

2

3

4

5

6

2. VERIFICATION OF KIRCHOFFS CURRENT& KIRCHOFFS VOLTAGE LAW

Exp.No: Date:..

AIMTo verify the Kirchoffs current and Kirchoffs voltage law by using standard Resistances, Ammeter and voltmeter.


1RPS 0-30-1

2Ammeter(0-100) mAMC2

3Voltmeter(0-50)VMC2

4Resistance10K5K-21

5Bread board--1


THEORY(A)KIRCHOFFS CURRENT LAW (FIRST LAW)The KCL states that the sum of current flowing towards a junction is equal to the sum of current flowing away from the junction. According to KCL,i1 + i3 + i5 = i2 + i4Sum of incoming current = Sum of Outgoing current(B) SECOND LAW (OR) VOLTAGE LAWThe algebraic sum of voltage in a closed circuit is equal to zero.(i.e) Algebraic sum of emfs + Algebraic sum of voltage drop = 0E = IR1 + IR2E IR1 IR2 = 0

KIRCHOFFS VOLTAGE LAW

CIRCUIT DIAGRAM

TABULATIONSl.NOVoltage V in voltsCurrent I in mAResistance in KI(R1+R2) mAV-I(R1+R2) in Volts

R1R2

1

2

3

4

5

6

PROCEDUREKCLs Law:1. Connections are given as per the circuit diagram.2. Switch on the power supply.3. The voltage is varied and the corresponding current I1, I2, I3 are tabulated.4. Verify the kirchoffs current law as I1=I2+I3.5. Repeat the above procedure. 6. Switch off the power supply.KVLs Law:1. Connections are given as per the circuit diagram.2. Switch on the power supply.3. The voltage is varied and the corresponding current through the resistances is noted.4. Verify the kirchoffs voltage law as E IR1 IR2 = 0.5. Switch off the power supply.

Result:Thus the KCL and KVL was verified by using standard resistances, ammeter and voltmeter.

VERIFICATION OF SUPER POSITION THEOREM

CIRCUIT DIAGRAM

a) DIRECT METHOD OF FINDING IL

b) V1 SOURCE SHORTED TO FIND IA

3. VERIFICATION OF SUPER POSITION THEOREM

Exp.No: Date:..

AIM:To verify the superposition theorem, for a common load, with two different D.C voltages.

APPARATUS REQUIRED:Sl. NoApparatus NameRangeTypeQuantity

1RPS 0-30-2


3Resistance10K5.6K-21

4Bread board--1


FORMULA:IL = I1+I2 mAI1 = Current due to one source, mAI2 = Current due to one source, mAIL = Total current at that point, mA

THEORY:In a linear circuit the response at any element due to several sources is given by the super position of the responses due to individual sources acting one at a time while the next of the sources reduced to zero values. To apply the super position theorem for the analysis of a linear circuit, the constant voltage sources are reduced to zero voltages(short circuit) and the constant current sources are reduced to zero current(open circuit).

CIRCUIT DIAGRAM

V2 SOURCE SHORTED TO FIND IB

TABULATIONSl.NoSource VoltagesIA in mAWith Source V1 ShortedIB in mAWith Source V2 ShortedIL in mA(Direct Method)IL=IA+IBin mA(Superposition method)

1VS1=VS2=

2VS1=VS2=

3VS1=VS2=

PROCEDURE:1. Connections are made as shown in the circuit diagram.2. Both Supplies are switched ON and the reading of ammeter is noted as IL.3. The source v2 is replaced by short circuit and the source v1 is switched ON, now the reading of Ammeter is noted asI1.4. The source v1 is replaced by short circuit and the source v2 is switched ON. Now the reading of Ammeter is noted as I2.5. Switch of the power supply.

RESULT:Thus the super position theorem was verified.

VERIFICATION OF THEVENINS THEOREMCIRCUIT DIAGRAMPRACTICAL PROOF TO FIND IL

THEORITICAL PROOFSTEP 1: TO FIND RTHReplace the voltage sources by their internal resistances as shown below.

R1 and R2 are in parallel therefore RTH = R1R2/(R1+R2)

RTH=.4. VERIFICATION OF THEVENINS THEOREM

Exp.No: Date:..

AIMTo verify Thevenins Theorem.


1RPS 0-30-1




5Bread board--1


FORMULA

CIRCUIT DIAGRAMSTEP 2: TO FIND VTH

Applying Kirchoffs voltage law we get VA-IR1-IR2-VB=0

Therefore I=.

Also, Va-IR1-VTH

VTH=.

THEORY:In any linear network contains voltage sources and resistances can be replaced by equivalent voltage source (VTH) in series with equivalent Resistance(RTH) if viewed from any one point in a network.Step1: Remove the load Resistor RL where current is required.Step2: Label the terminal from which RL is removed.Step3: Calculate the open circuit voltage across the labeled terminal. This is the Thevenins voltage (VTH).Step4: Draw the equivalent circuit.Step5: Find the current in RL using the formula, IL= VTH / (RTH=RL)

PROCEDURE 1. Connections are made as shown in the circuit diagram.2. Switch ON the power supply.3. The load current is noted from Ammeter.4. The load resistance RL and ammeter are removed from the circuit and VTH is formed.5. The RPS is also removed and RTH is found.6. Now we can draw Thevenins equivalent circuit which consists of RTH and RL connected in series with VTH.7. Now we can find IL.

STEP 3: THEVENIENS EQUIVALENT CIRCUIT TO FIND IL:

RESULTThus the Thevenins Theorem was verified.1.Practical value of IL=:2.Theoretical value of IL=:..

VERIFICATION OF NORTONS THEOREM

CIRCUIT DIAGRAMPRACTICAL PROOF TO FIND IL

THEORITICAL PROOFSTEP 1: TO FIND RNReplace the voltage sources by their internal resistances as shown below.

R1 and R2 are in parallel therefore RN = R1R2/(R1+R2) =

RN=5. VERIFICATION OF NORTONS THEOREM

Exp.No: Date:..

AIM To verify Nortons theorem.


1RPS 0-30-1

2Ammeter(0-100) mA1


4Bread board--1


FORMULA Where IL = Load current in (mA) IN = Norton current in (mA) RN = Nortons equivalent Resistance in (k_) RL = Load Resistance in (k_) Resistance (RTH) if viewed from any one point in a network

To Find IN:To Find IL:10K_ 10K_+-RPS(030)V 5.6K_A+-(010)mARN 1.5K_ILINECE Department ECI Lab Manual25

Nortons Theorem:Any two terminal active linear network containing voltage sources and resistance when viewed from its output terminals, is equivalent to a constant current source and a parallel resistance. The constant current is equal to the current which would flow ion a short circuit placed across the terminals and parallel resistance is the resistance of the network when viewed from these open circuited terminals after all voltage and current sources have been removed and replaced by their internal resistances.Step1: Remove the load Resistor RL (if any) and put a short circuit acrossStep2: Find the short circuit current.Step3: Calculate the Nortons looking back resistance RN from the Load Terminal.Step4: Draw the equivalent circuit.Step5: Find the current in RL using the formula,

Procedure:1. Connections are made as shown in the circuit diagram.2. Switch ON the power supply.3. The load resistance RL and ammeter are removed from the circuit and IN values is noted.4. The RPS is also removed and RN is found.5. Now we can draw Nortons equivalent circuit.6. Now we can find the value of load current IL.

Tabulation for Nortons Theorem:Load current(IL) in mA Nortons Resistance (R N)in K_ Nortons Current(IN)in mAModel Calculation for Nortons Theorem:Result:Thus the Nortons theorem was verified.

VERIFICATION OF MAXIMUM POWER TRANSFER THEOREM

CIRCUIT DIAGRAM

TABULATIONSl.NoLoad Resistance RL in KFor V=For V=

Current I in mAP= V*I WattsCurrent I in mAP= V*I Watts

1

2

3

4

5

6

7

8

9

10

11

12

6. VERIFICATION OF MAXIMUM POWER TRANSFER THEOREM

Exp.No: Date:..

AIMTo verify, maximum power transfer theorem.

Apparatus Required:Sl. NoApparatus NameRangeTypeQuantity

1RPS 0-30-1



4Resistance1.5K-3

5Decade resistance box--1

6Bread board--1


THEORYThe maximum power transfer theorem states that the maximum power is transferred from a source to load when the load resistance is made equal to the internal resistance or looking back resistance of the network from the load terminals.i.e., RL =RI=RTHMaximum power transferred=

MODEL GRAPH

MODEL CALCULATION

PROCEDURE1. The connections are made as shown in the circuit diagram.2. Keep the supply voltage constant by varying DRB and the corresponding ammeter and voltmeter readings are noted.3. Plot the curve between load resistance and power.4. Switch off the power supply.

Result:Thus the maximum power transfer theorem was verified and the graph was drawn.

Circuit diagram:Tabulation for Open Circuit Test:Multiplying Factor =Vo(volts) Io(A) Woc (watts) Actual Reading=ObservedReading *Multiplying Factor

7. OC AND SC TEST ON A SINGLE PHASE TRANSFORMER

Exp.No: Date:..

Aim:To conduct the open circuit and the short circuit test on a single phase transformer and determine the percentage of efficiency.

Apparatus Required:Sl.NoApparatus NameRangeTypeQuantity

1Ammeter

2

3

4

5

6

7

8

1. (0-5)A MI 12. Ammeter (0-10)A MI 13. Voltmeter (0-150)V MI 14. Voltmeter (0-300)V MC 15. Wattmeter 300V,5A Dynamometer 16. Auto transformer - - 17. Transformer - - 18. Connecting wires - - 10

Formula Used:Iron loss = WocCopper loss = WscTotal loss = Woc+WscOutput power = capacity*cos F100(Input Power)(Output Power)%of efficiency =

Theory:Open Circuit Test:Open circuit test is called as no load test. The purpose of this test is todetermine no-load loss or core loss and no load current Io which is helpful in windingRo&Xo.Supply is given to the primary winding through a wattmeter with secondarywinding open circuited. The readings of the wattmeter gives the no load losses whenrated voltage is applied to the primary. No load current is very small and the primaryresistance is negligible.Therfore copper loss (I2R) is very small. The input to thetransformer.Tabulation for Short Circuit Test:Short Circuit Test:Short circuit test can be determined by the copper loss. The copper lossoccurs when the current flows through the winding .It is equal to I2R. This loss variesas the square of the load current knowing the load current and the equivalentresistance of secondary side the copper loss can be calculated by using an autotransformer the input voltage is varied from zero to small value. This is applied to theprimary winding .Secondary winding is short circuited using the ammeter. Voltage isvaried slowly till the secondary side ammeter reads rated secondary rated current.As the primary voltage is very small, the iron loses are assumed to be small andneglected. The wattmeter reading gives the total copper losses at full load current.

Procedure:Open Circuit Test or No Load Test:1. The connections are made as shown in the circuit diagram.2. The primary terminal of the high voltage side of transformer is kept up to n.3. The power supply is switched ON by adjusting the auto transformer. The rate voltage is applied to their position the voltmeter readings are noted.4. Switch OFF the power supply.Short Circuit Test or Impedance Test:1. The connections are made as shown in the circuit diagram2. The secondary terminal of the low voltage side of transformer is kept as short circuit.3. The power supply is switched ON at this position of the voltage.4. Ammeter and voltmeter readings are noted.5. Switch OFF, the power supply.

Model Calculation:

Result:Thus the open circuit and short circuit are conducted and the efficiency is calculated.1. % Efficiency = -------------------------2. Iron loss = -------------------------3. Copper loss = -------------------------

CIRCUIT DIAGRAM

Given MeterStandard MeterCALIBRATION OF AMMETER

CALIBRATION OF VOLTMETER

Standard MeterGiven Meter

8. CALIBRATION OF AMMETER AND VOLTMETER

Exp.No: Date:..

AIMTo calibrate a D.C ammeter and a D.C voltmeter, using a standard meter.


1RPS 0-30-1



4Resistance1K-1

5Decade resistance box--1

6Bread board--1


PROCEDURE1. The connections are made as shown in the circuit diagram2. Switch ON the power supply.3. The RPS is varied and the corresponding standard and test meter readings are noted and tabulated.4. Switch OFF the power supply.

TABULATIONCALIBRATION OF VOLTMETERSl.NoStandard meter ReadingVs (Volts)Given meter ReadingVe (Volts)ErrorVs-Ve (Volts)% of Error

Graph:Error Curve:It is drawn by taking test meter reading along X axis and error along Y axis.Result:Thus the voltmeter and ammeter were calibrated with standard voltmeter and ammeter respectively.

WHEATSTONES BRIDGE

CIRCUIT DIAGRAM

TABULATIONSL.NOP in OhmsQ in OhmsDRB (S) in OhmsRx= (P*S)/Q

1

2

3

4

9. WHEATSTONES BRIDGE

Exp.No: Date:..

AIMTo determine the unknown resistance value using wheatstones bridge.


1RPS 0-30-1


3Resistance12K33K-11

4Decade Resistance Box--1

5Bread board--1


FORMULAUnder balanced condition P*S=Q*Rx Therefore Rx= (P*S)/Q THEORYA very important device used in the measurement of medium resistances is the wheat stone bridge. It is still an accurate and reliable instrument and reliable instrument and is extensively used in industry. The wheat stone bridge is an instrument for making comparison measurements and operator upon a null indication principle. This means the indication is independent of the calibration of the null indicating instrument or any of its characteristics. For this reason, very high degree of accuracy can be achieved using wheat stone bridge. It is used to measure low and medium value resistances.Figure shows the basic circuit, of a wheat stone bridge. It has four resistive arms, consisting of resistances P, Q, R and S together with a source of emf (a battery) and a null detector (galvanometers) or other sensitive current meter. The bridge is said to be balanced when there is no current through the galvanometer or when the pot. Difference across the galvanometer is zero.

CALCULATION

PROCEDURE1. Connections are made as shown in the circuit diagram.2. Switch on the power supply and set the power supply to 5 volt.3. By varying DRB, the voltage across the galvanometer is mode zero and the corresponding value of S is noted in tabular column.4. The unknown resistance value is found by using the formula. Rx= (P*S)/Q5. Step 3 and 4 are repeated for different value of unknown resistances.6. Switch Off the power supply.

RESULTThus the value of the unknown resistance is found out by using Wheat stones bridge.

WIEN BRIDGE MEASURING FREQUENCY

CIRCUIT DIAGRAM

10. WEIN BRIDGE

Exp.No: Date:..

AIMTo determine the unknown capacitance value using wein bridge.


1Function Generator--1

2CRO--1

3Capacitor1F-2


5Decade Resistance Box--1

6Bread board--1


FORMULAFrequency f = By choosing R1 = R3 = R and C1=C2=CThen frequency f = Hz

THEORYWien Bridge is used as an AC Bridge. This is used to measure frequency. Wien Bridge is used as a notch filter in the harmonic distortion analyzer. It is also used in audio and high frequency oscillators, for determining frequency. This Bridge is used for measuring frequency in the audio range. Capacitors C1 and C2 are normally of fixed values. Resistances R1 and R3 are having identical values. In the audio range (from 20-200-2k-20kHz), the resistances are used for range changing and capacitors C1 and C3 are used for the frequency control.TABULATION

PROCEDURE1. Switch on the power supply.2. Set the value of frequency in FG.3. Vary the value of capacitance & Resistance, until a clear sine wave is obtained at the CRO.4. Note down the value of resistance and capacitance in the tabular column.5. Find the value of calculated.

RESULTThus the unknown frequencies were found out by using Wiens Bridge.

CIRCUIT DIAGRAM

TABULATIONSL.NODistance in cmVoltage in voltsCurrent in mA

1

2

3

4

5

6

7

11. PHOTO ELECTRIC TRANSDUCER

Exp.No: Date:..

AIMTo determine the VI characteristics, of photoelectric transducer (LDR).


1RPS 0-30-1



4Resistance1K-1

5LDR--1

6Incandescent Lamp230V/60W-1

7Bread board--1


THEORYLDR is a photoelectric transducer. LDR is a semiconductor device, whose resistance value changes when exposed to light. The LDR operates with the principle of photo conductive effect. The value of resistance is about 2M at absolute darkness. I strong incident light its resistance value is about 10 only.The photoconductive materials used are Cadmium Sulphide, Cadmium Selenide or Cadmium Sulpho Selenide. These materials are very sensitive to light radiation.

MODEL GRAPH

PROCEDURE1. The connections are made as shown in the circuit diagram.2. Switch ON the power supply and setting the fixed voltage.3. Now the bulb is ON and its placed at certain distance.4. The distance is increased or decreased and corresponding ammeter readings are noted and tabulated.5. Switch OFF the power supply.

GRAPHIt is drawn by taking distance along X axis and current along Y axis.

RESULTThus the characteristic of photoelectric transducer (LDR) was determined and the graph was drawn.

TO MEASURE THE PHASE ANGLECIRCUIT DIAGRAM

TO MEASURE THE FREQUENCY

12. MEASUREMENT OF FREQUENCY AND PHASE ANGLE

Exp.No: Date:..

AIMTo measure the frequency and phase angle using lissajious figure.


1CRO--1



THEORY FREQUENCY MEASUREMENTTo measure a frequency, the waveform viewed by the oscilloscope must be periodic. For example, the period of the sine function is between any two alternate zero crossing. The period can also be measured between any two positive peaks or any two negative peaks. The frequency is determined by, Frequency = 1/period

PHASE ANGLE MEASUREMENTIt is interesting to consider the characteristics of patterns that appear on the screen of a CRT when sinusoidal voltages are simultaneously applied to horizontal and vertical plates. These patterns are called Lissajous patterns. When two sinusoidal voltages of equal frequency, which are in phase with each other, are applied to the horizontal and vertical deflection plates, the pattern appearing on the screen is a straight line. Thus when two equal voltages of equal frequency but with 90 phase displacement are applied to a CRO, the trace on the screen is a circle. When two equal voltages of equal frequency but with a phase shiftof (not equal to 0 or 90) are applied to a CRO we obtain an ellipse. The phase angle is either between 0 or 90 or between 270 to 360. When the major axis of ellipse lies in second and fourth quadrants i.e. when its slope is negative, the phase angle is either between 90 and 180 or between 180and 270.

FREQUENCY MEASUREMENTTABULATION

PROCEDUREMEASUREMENT OF PHASE ANGLE1. Connections are made as shown in the circuit diagram2. A sinusoidal voltage is applied to the horizontal and vertical input with same magnitude.3. Press the X Y button in the CRO. Now an ellipse is drawn on the CRO.4. From this ellipse, the value of A & B is noted and phase angle is measured.

MEASUREMENT OF FREQUENCY1. The connections are made as shown in the circuit diagram.2. A known frequency (FH) is applied to the horizontal input using step down transformer.3. By varying unknown frequency, a pattern with loops is obtained.4. The number of lines which cut the horizontal input is noted as TH. Similarly the number of lines cut the vertical input is noted as TV.6. From the values FH, TH, TV, the value of unknown frequency is calculated.

GRAPHIt is drawn by taking TH along X axis and TV along Y axis.

RESULTThus the Phase Angle and Frequency were measured using lissajious figure.

CIRCUIT DIAGRAM

TABULATION

13. MEASUREMENT OF FREQUENCY AND AMPLITUDE USING CRO

Exp.No: Date:..

AIMTo measure the frequency and amplitude using dual trace CRO for different circuit.


1CRO--1



THEORYThe oscilloscope consists of one set of horizontal plates (X-plate) and one set of vertical plates (Y-plate). The horizontal plates are connected to the vertical input points. A ramp generator generates a time base saw tooth voltage. The input to the Horizontal plates (X-input) can be applied either internally from the time base generator or externally. The voltage or the signal, which is to be analyzed, is applied to the vertical plates (Y-input). The electrons emitted by the cathode towards a phosphor coated screen causes a luminous spot on the screen. The spot moves horizontally due to the electrostatic deflection caused by the X-plates.

MODEL GRAPH

PROCEDURE1. The connections are made as shown in the circuit diagram.2. Switch ON the CRO.3. The Function generator is connected to the CRO.4. By varying the frequency, the readings are noted and tabulated.5. Switch OFF the power supply.

RESULTThus the frequency and amplitude were measured by using CRO.

RLC BRIDGE:WHEATSTONES BRIDGEWEIN BRIDGE CIRCUIT DIAGRAM

14. RLC BRIDGE

Exp.No: Date:..

AIMTo measure the value of the Resistance, Inductance and Capacitance, using RLC bridge.

APPARATUS REQUIRED

THEORYA simple bridge for the measurement of resistance, capacitance and inductance may be constructed with four resistance decades in one arm, and binding post terminals to which external resistors or capacitors may be connected, to complete the other arms. Such a skeleton arrangement is useful in the laboratory, since it permits the operator to set up a number of different bridge circuits simply by plugging standards and unknown units into the proper terminals.

PROCEDURE1. At first we can set the components in the digital bridge.2. The dial is positioned in the corresponding resistance, inductance and the capacitance mode.3. Now the value should be noted from the display of the segment.

TABULATIONRLC bridge measurementS.No. APPARATUS DIGITAL VALUE ACTUAL VALUE

Result:Thus the value of the Resistance, Inductance and Capacitance were measured using Digital RLC Bridge.

Strain Gauge Measurement:

15. STRAIN GAUGE MEASUREMENT

AIMTo measure the strain in the beam using Strain Gauge Trainer Kit.

APPARATUS REQUIRED

Theory:The strain gauge is an example of a passive transducer that uses the variation in electrical resistance in wires to sense the strain produced by a force on the wires. It is well known that stress (force/unit area) and strain (elongation or compression/unit length) in a member or portion of any object under pressure is directly related to the modulus of elasticity. Since strain can be measured more easily by using variable resistance transducers, it is a common practice to measure strain instead of stress, to serve as an index of pressure. Such transducers are popularly known as strain gauges. If a metal conductor is stretched or compressed, its resistance changes on account of the fact that both the length and diameter of the conductor changes. Also, there is a change in the value of the Resistivity of the conductor when subjected to strain, a property called the Piezo resistive gauges. When a gauge is subjected to a positive stress, its length increases while its area of cross section decreases. Since the resistance of a conductor is directly proportional to its length and inversely proportional to its area of cross section, the resistance of the gauge increases with positive strain. The change in resistance value of a conductor under strain is more than for an increase in resistance due to its dimensional changes. This property is called the Piezo resistive effect.

Tabulation:Strain Gauge Measurement

Procedure:1. The connections are made shown in the circuit diagram.2. Switch ON the Stain Gauge tutor.3. The bridge output and display readings are noted without applying any load inthe input.4. Then the input load is applied and the corresponding readings are taken.5. The load is increased in 100gm for each step and readings are tabulated.6. Switch OFF the supply.

Model Graph:The graph is drawn by taking Load along X axis and display reading along Y axis.

Result:Thus the Strain in the beam was measured using Strain Gauge Trainer Kitand Cantilever Beam.

Viva Questions:1. What is hysteretic effect in strain gauge?2. What are the types of strain gauge?3. Define Gauge factor.4. What is Piezo resistive effect?5. What is the material used for making strain gauge transducer?6. What is semi conductor strain gauge?ECE Department ECI Lab Manual78Load Cell Measurement:SENSOR5VDCOFFSETTp2GainTp4Tp3 Gain(0-5) V o/pP4T4 T5T2T3SG1 SG2SG3SG4+-DPMT6ECE Department ECI Lab Manual7916. MEASUREMENT OF LOAD CELLAim:To measure the load using Load Cell Trainer Kit and load cell panel.Apparatus Required:S.NO Apparatus name Quantity1. Load Cell Trainer Kit 12. Load Cell Panel 13. Multimeter 14. Load (0 - 5) KgTheory:The load cell is an electromechanical sensor employed to measure static anddynamic forces. The device can be designed to handle a wide range of operatingforces with high level of reliability, and hence is it one of the most popular transducerin industrial measurements. The load cell derives its output from the deformation ofan elastic member having high tensile strength.Procedure:1. The connections are made as shown in the circuit diagram.2. Initially one Kg load is applied and the corresponding readings are noted.3. Then the load is increased in step by step and the corresponding readings arenoted and tabulated.Model Graph:The graph is drawn by taking load along X axis and display reading along Y axis.Application:To measure high value of static and dynamic forces or pressure.ECE Department ECI Lab Manual80Display ReadingsIn voltsLOAD in KgTabulation:Load Cell MeasurementS. No. LOAD in Kg BRIDGE OUTPUT(T2, T3) mVDISPLAY READINGVoltsModel graph:ECE Department ECI Lab Manual81Result:Thus the load was measured using Load Cell Trainer Kit & Load Cell Panel.Viva Question:1. Is there any difference between sensor and transducer?2. What is the transducer used to measure low-pressure measurement?3. What is the use of Piezo resistive transducers?ECE Department ECI Lab Manual82LVDT Measurement:OscillationTp6 OFFSETTp5 Gain(0-5) V o/pP4TP3DPMT1T8 T7BufferT6Non Inverting AmplifierNon InvertingAmplifierTP2 - OFFSETPhaseReferenceAmplifierT3T2 T4CORELVDT ACAmplifierHalf wavesync RC FilterECE Department ECI Lab Manual8317. LVDT MEASUREMENTAim:To measure the displacement using LVDT Trainer Kit.Apparatus Required:S.NO Apparatus name Quantity1. LVDT Trainer Kit 12. Screw Gauge 13. Multimeter 1Theory:The differential transformer is a passive inductive transformer. It is also knownas a Linear Variable Differential Transformer (LVDT). The transformer consists of asingle primary winding P1 and two secondary windings S1 and S2 wound on a hollowcylindrical former. The secondary windings have an equal number of turns and areidentically placed on either side of the primary winding. The primary winding isconnected to an ac source. An movable soft iron core slides within the hollow formerand therefore affects the magnetic coupling between the primary and the twosecondaries. The displacement to be measured is applied to an arm attached to thesoft iron core. (Ni iron alloy)When the core is in its normal (null) position, equal voltages are inducedin the two secondary windings. The frequency of the ac applied to the primarywinding ranges from 50Hz to 20KHz.The output voltage of the secondary windings S1 is Es1 and that of secondarywinding S2 is Es2.In order to convert the output from S1 to S2 into a single voltage signal, the twosecondaries S1 and S2 are connected in series opposition.Hence the output voltage of the transducer is the difference of the twovoltages. Therefore the differential output voltage E0 =Es1 ~ Es2.Procedure:1. The connections are made as shown in the circuit diagram.2. The power supply is switched ON.3. The screw gauge is adjusted so that the LVDT reads 8mm.4. The displacement of core is reduced by adjusting the Screw Gauge stepby step by 2mm and the corresponding readings are noted.5. The Screw Gauge is adjusted up to the LVDT reads 8mm. the ScrewGauge reading is noted and display reading is noted across T1 and T8.6. The power supply is switched OFF.ECE Department ECI Lab Manual84Tabulation:LVDT Measurement:S.No.Screw guageReadings (mm) LVDT Display LVDT output Readings (v)Model Graph:LVDT Display Readings (mV)LVDT Output Readings (V)ECE Department ECI Lab Manual85Model Graph:The graph is drawn by taking LVDT reading along X axis and displayreading along Y axis.Application: It is widely used for measurement of displacement where linear displacementfrom few mm to few cm. It is widely used in data systems to measure linear displacement, velocity,acceleration, pressure, force, level, and rate of flow of liquids.Result:Thus the displacement was measured using LVDT Trainer Kit.Viva Question:1. Is the output voltage of LVDT linear?2. How much is the power consumption of LVDT?ECE Department ECI Lab Manual86Measurement of Temperature:Characteristics of Thermistor:GR2AR1R3ThermistorC+ - D(0-30) V+-Temperature in oCPlatinumSpecific Resistance (W cm)ThermistorECE Department ECI Lab Manual87

18. THERMISTOR

AIMTo study the construction, operation and characteristics of Thermistor.Result:Thus the construction, operation and characteristics of Thermistors werestudied.Viva Question:1. Where Thermistor is applied?2. What is active transducer?3. What is passive transducer?4. What is negative temperature co-efficient?ECE Department ECI Lab Manual90Circuit Diagram:(0 100) mAA(0 30) V A (0 50) mARPS1K_RshDRB+ ++ ---ECE Department ECI Lab Manual9119. EXTENDING THE RANGE OF AMMETERAim:To extend the range of Ammeter and calibrate the Ammeter with the standardmeter.Apparatus Required:S. NO APPARATUS NAME RANGE QUANTITY1. RPS (0-30)V 12. Ammeter (0-100) mA(0-50) mA113. DRB - 14. Bread Board - 15. Wires - -Formula:Shunt resistance(I Im)(ImRm)Rsh-=(m 1)RmRsh-=Multiplication FactorImIm =Theory:The range of an electrical measurement is actually limited by the current.This current can be carried by the coil of the instrument safely. The moving coil andthe spiral springs are used as coil connectors. These can be designed for amaximum current of only 50mA and a potential drop of above 50mV. So, farmeasuring large current or voltage, the range of the instrument has to be extended.The common devices employed for extending the range of instruments areshunts and multipliers. When instruments are supplied with such external devices,the instrument is calibrated over the range of associated shunt or multiplier.The basic movement of a DC ammeter is a permanent magnet moving coilgalvanometer. The basic movement coil is small and light. So it can carry only a verysmall current. When large current is to be measured, it becomes necessary tobypass the major part of current through shunt resistance.An ammeter shunt is merely a low resistance. This is placed in parallel withthe instrument coil circuit to measure large current.ECE Department ECI Lab Manual92Tabulation:Extending the Range of Ammeter:S.NO. IS in(mA)IT = m * IT(mA)Error =(IT - IS)(mA)Correction=(IS - IT)(mA)Model Graph:Error Curve Correction CurveIs in m AIT in mA CORRECTION in mAERROR in mAECE Department ECI Lab Manual93Procedure:1. Connections are made as per the circuit diagram.2. The power supply is switched ON.3. RM is found by using Multimeter and find RSH.4. By varying RPS test meter, standard meter readings are noted andtabulated.5. The power supply is switched OFF.Graph:Error Curve:It is drawn by taking Is along X axis and error along Y axis.Correction Curve:It is drawn by taking IT along X axis and correction along Y axis.Application:The range of ammeter can be extended by using a suitable shunt across itsterminals. By using this experiment, we can increase the measuring capacity ofinstrument.Result:Thus the range of ammeter was extended and the ammeter was calibratedwith the standard meter.Viva Question:1. How do we extend the range of ammeter?2. What is damping torque?3. What is the use of controlling torque?VERIFICATION OF THEVENINS THEOREMCIRCUIT DIAGRAMPRACTICAL PROOF TO FIND IL

THEORITICAL PROOFSTEP 1: TO FIND RTH

RTH =

15. VERIFICATION OF THEVENINS THEOREM

Exp.No: Date:..

AIM:To verify Thevenins Theorem.

APPARATUS REQUIRED:Sl. NoApparatus NameRangeTypeQuantity

1RPS 0-30-1




5Bread board--1


FORMULA:

CIRCUIT DIAGRAMSTEP 2: TO FIND VTH:

STEP 3: THEVENIENS EQUIVALENT CIRCUIT TO FIND IL:

THEORY:In any linear network contains voltage sources and resistances can be replaced by equivalent voltage source (VTH) in series with equivalent Resistance(RTH) if viewed from any one point in a network.Step1: Remove the load Resistor RL where current is required.Step2: Label the terminal from which RL is removed.Step3: Calculate the open circuit voltage across the labeled terminal. This is the Thevenins voltage (VTH).Step4: Draw the equivalent circuit.Step5: Find the current in RL using the formula, IL= VTH / (RTH=RL)

PROCEDURE:1. Connections are made as shown in the circuit diagram.2. Switch ON the power supply.3. The load current is noted from Ammeter.4. The load resistance RL and ammeter are removed from the circuit and VTH is formed.5. The RPS is also removed and RTH is found.6. Now we can draw Thevenins equivalent circuit which consists of RTH and RL connected in series with VTH.7. Now we can find IL.

RESULT:Thus the Thevenins Theorem is verified.

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