Ece Department Eci Lab Manual 256x2l
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TABLE OF CONTENTS
ECE Department ECI Lab Manual
VERIFICATION OF OHM’S LAW
CIRCUIT DIAGRAM
TABULATION S.NO
Voltage across R
Current through R
V in Volts
I in (mA)
Resistance R=V/I in ohm
1. VERIFICATION OF OHM’S LAW Exp.No:……
Date:……………..
AIM To the ohm‟s law using standard resistances, Ammeter and voltmeter.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
1
3
Voltmeter
(0-50)V
1
4
Resistance
1KΩ
-
1
5
Bread board
-
-
1
6
Connecting wires
-
-
As Required
THEORY OHM’S LAW The 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 = IR Where V = Voltage (potential difference) in volts I = Current in milli Amperes R=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 ohm‟s law was verified using standard resistances, ammeter and voltmeter.
KIRCHOFF’S CURRENT LAW CIRCUIT DIAGRAM
TABULATION Sl.NO 1 2 3 4 5 6
Voltage V in volts
Current I in mA I1
I2
I3=I1+I2 mA I3
2. VERIFICATION OF KIRCHOFF’S CURRENT & KIRCHOFF’S VOLTAGE LAW Exp.No:……
Date:……………..
AIM To the Kirchoff‟s current and Kirchoff‟s voltage law by using standard Resistances, Ammeter and voltmeter.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
2
3
Voltmeter
(0-50)V
MC
2
4
Resistance
10KΩ 5KΩ
-
2 1
5
Bread board
-
-
1
6
Connecting wires
-
-
As Required
THEORY (A)KIRCHOFF’S 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 + i4 Sum of incoming current = Sum of Outgoing current (B) SECOND LAW (OR) VOLTAGE LAW The algebraic sum of voltage in a closed circuit is equal to zero. (i.e) Algebraic sum of emfs + Algebraic sum of voltage drop = 0 E = IR1 + IR2 E – IR1 – IR2 = 0
KIRCHOFF’S VOLTAGE LAW
CIRCUIT DIAGRAM
TABULATION Sl.NO 1 2 3 4 5 6
Voltage V in Current I in mA volts
Resistance in KΩ R1 R2
I(R1+R2) mA
V-I(R1+R2) in Volts
PROCEDURE KCL’s 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. the kirchoff‟s current law as I1=I2+I3. 5. Repeat the above procedure. 6. Switch off the power supply. KVL’s 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. the kirchoff‟s 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 the superposition theorem, for a common load, with two different D.C voltages.
APPARATUS REQUIRED: Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
2
1
RPS
2
Ammeter
(0-100) mA
MC
1
3
Resistance
10KΩ 5.6KΩ
-
2 1
4
Bread board
-
-
1
5
Connecting wires
-
-
As Required
FORMULA: IL = I1+I2 mA I1 = Current due to one source, mA I2 = Current due to one source, mA IL = 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
TABULATION
Sl.No
1
2
3
Source Voltages
VS1= VS2= VS1= VS2= VS1= VS2=
IA in mA
IB in mA
With Source V1
With Source
Shorted
V2 Shorted
IL=IA+IB IL in mA
in mA
(Direct Method)
(Superposition method)
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 THEVENIN’S THEOREM CIRCUIT DIAGRAM PRACTICAL PROOF TO FIND IL
THEORITICAL PROOF STEP 1: TO FIND RTH Replace the voltage sources by their internal resistances as shown below. R2
R1 100 Ohm
100 Ohm
A
A R1
B
B
R1 and R2 are in parallel therefore RTH = R1R2/(R1+R2)
RTH=………….
100 Ohm
R2 100 Ohm
4. VERIFICATION OF THEVENIN’S THEOREM Exp.No:……
Date:……………..
AIM To Thevenin‟s Theorem.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
1
3
Voltmeter
(0-10)V
MC
1
4
Resistance
10KΩ 5.6KΩ
-
2 1
5
Bread board
-
-
1
6
Connecting wires
-
-
As Required
FORMULA
CIRCUIT DIAGRAM STEP 2: TO FIND VTH R1
R2
100 Ohm
100 Ohm
A
Va 0-30 Vdc
I
B
Applying Kirchoffs voltage law we get VA-IR1-IR2-VB=0
Therefore I=…………. Also, Va-IR1-VTH
VTH=………….
Vb 0-30 Vdc
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 Thevenin‟s 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 Thevenin‟s 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:
RESULT Thus the Thevenin‟s Theorem was verified. 1.Practical value of IL=:…………… 2.Theoretical value of IL=:…………..
VERIFICATION OF NORTON’S THEOREM
CIRCUIT DIAGRAM PRACTICAL PROOF TO FIND IL
THEORITICAL PROOF STEP 1: TO FIND RN Replace the voltage sources by their internal resistances as shown below. R2
R1 100 Ohm
100 Ohm
A
A R1
B
B
R1 and R2 are in parallel therefore RN = R1R2/(R1+R2) =
RN=
100 Ohm
R2 100 Ohm
5. VERIFICATION OF NORTON’S THEOREM Exp.No:……
Date:……………..
AIM To Norton‟s theorem.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
3
Resistance
10KΩ 5.6KΩ
-
2 1
4
Bread board
-
-
1
5
Connecting wires
-
-
As Required
1
FORMULA
Where IL = Load current in (mA) IN = Norton current in (mA) RN = Norton‟s 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 (0–30)V 5.6K_ A + (0–10)mA RN 1.5K_ IL IN ECE Department ECI Lab Manual 25
Norton’s 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 across Step2: Find the short circuit current. Step3: Calculate the Norton‟s 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 Norton‟s equivalent circuit. 6. Now we can find the value of load current IL.
Tabulation for Norton’s Theorem: Load current(IL) in mA Norton’s Resistance (R N)in K_ Norton’s Current(IN)in mA Model Calculation for Norton’s Theorem: Result: Thus the Norton‟s theorem was verified.
VERIFICATION OF MAXIMUM POWER TRANSFER THEOREM
CIRCUIT DIAGRAM
TABULATION Sl.No 1 2 3 4 5 6 7 8 9 10 11 12
Load Resistance RL in KΩ
For V= Current I P= V*I Watts in mA
For V= Current I in P= V*I Watts mA
6. VERIFICATION OF MAXIMUM POWER TRANSFER THEOREM Exp.No:……
Date:……………..
AIM To , maximum power transfer theorem.
Apparatus Required: Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
1
3
Voltmeter
(0-10)V
MC
1
4
Resistance
1.5KΩ
-
3
5
Decade resistance box
-
-
1
6
Bread board
-
-
1
7
Connecting wires
-
-
As Required
THEORY The 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=RTH Maximum power transferred=
MODEL GRAPH
MODEL CALCULATION
PROCEDURE 1. 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=Observed Reading *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.No
Apparatus
Range
Name 1
Ammeter
2 3 4 5 6 7 8 1. (0-5)A MI 1 2. Ammeter (0-10)A MI 1 3. Voltmeter (0-150)V MI 1 4. Voltmeter (0-300)V MC 1 5. Wattmeter 300V,5A Dynamometer 1 6. Auto transformer - - 1 7. Transformer - - 1 8. Connecting wires - - 10
Formula Used: Iron loss = Woc
Type
Quantity
Copper loss = Wsc Total loss = Woc+Wsc Output power = capacity*cos F 100 (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 to determine no-load loss or core loss and no load current Io which is helpful in winding Ro&Xo.Supply is given to the primary winding through a wattmeter with secondary winding open circuited. The readings of the wattmeter gives the no load losses when rated voltage is applied to the primary. No load current is very small and the primary resistance is negligible.Therfore copper loss (I2R) is very small. The input to the transformer. Tabulation for Short Circuit Test: Short Circuit Test: Short circuit test can be determined by the copper loss. The copper loss occurs when the current flows through the winding .It is equal to I2R. This loss varies as the square of the load current knowing the load current and the equivalent resistance of secondary side the copper loss can be calculated by using an auto transformer the input voltage is varied from zero to small value. This is applied to the primary winding .Secondary winding is short circuited using the ammeter. Voltage is varied 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 and neglected. 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 diagram 2. 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 CALIBRATION OF AMMETER Standard Meter
Given Meter
CALIBRATION OF VOLTMETER
Given Meter Standard Meter
8. CALIBRATION OF AMMETER AND VOLTMETER Exp.No:……
Date:……………..
AIM To calibrate a D.C ammeter and a D.C voltmeter, using a standard meter. APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
2
3
Voltmeter
(0-10)V
MC
2
4
Resistance
1KΩ
-
1
5
Decade resistance box
-
-
1
6
Bread board
-
-
1
7
Connecting wires
-
-
As Required
PROCEDURE 1. The connections are made as shown in the circuit diagram 2. 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.
TABULATION CALIBRATION OF VOLTMETER Sl.No
Standard meter Reading
Given meter Reading
Error
Vs (Volts)
Ve (Volts)
Vs-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.
WHEATSTONE’S BRIDGE
CIRCUIT DIAGRAM
TABULATION SL.NO
P in Ohms
Q in Ohms
DRB (S) in Ohms
Rx= (P*S)/Q
1 2 3 4
9. WHEATSTONE’S BRIDGE Exp.No:……
Date:……………..
AIM To determine the unknown resistance value using wheatstone‟s bridge.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Voltmeter
(0-10)V
MC
1
3
Resistance
12KΩ 33KΩ
-
1 1
4
Decade Resistance Box
-
-
1
5
Bread board
-
-
1
6
Connecting wires
-
-
As Required
FORMULA Under balanced condition P*S=Q*Rx Therefore Rx= (P*S)/Q
THEORY A 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
PROCEDURE 1. 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)/Q 5. Step 3 and 4 are repeated for different value of unknown resistances. 6. Switch Off the power supply.
RESULT Thus the value of the unknown resistance is found out by using Wheat stone‟s bridge.
WIEN BRIDGE MEASURING FREQUENCY
CIRCUIT DIAGRAM
10. WEIN BRIDGE Exp.No:……
Date:……………..
AIM To determine the unknown capacitance value using wein bridge. APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
1
Function Generator
-
-
1
2
CRO
-
-
1
3
Capacitor
1µF
-
2
4
Resistance
10KΩ 5.6KΩ
-
2 1
5
Decade Resistance Box
-
-
1
6
Bread board
-
-
1
7
Connecting wires
-
-
As Required
FORMULA Frequency f =
√
By choosing R1 = R3 = R and C1=C2=C Then frequency f =
Hz
THEORY Wien 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
PROCEDURE 1. 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.
RESULT Thus the unknown frequencies were found out by using Wien‟s Bridge.
CIRCUIT DIAGRAM
TABULATION SL.NO
Distance in cm
Voltage in volts
Current in mA
1 2 3 4 5 6 7
11. PHOTO ELECTRIC TRANSDUCER
Exp.No:……
Date:……………..
AIM To determine the VI characteristics, of photoelectric transducer (LDR).
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
1
3
Voltmeter
(0-10)V
MC
1
4
Resistance
1KΩ
-
1
5
LDR
-
-
1
6
Incandescent Lamp
230V/60W
-
1
7
Bread board
-
-
1
8
Connecting wires
-
-
As Required
THEORY LDR 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 2MΩ at absolute darkness. I strong incident light its resistance value is about 10Ω only. The photoconductive materials used are Cium Sulphide, Cium Selenide or Cium Sulpho Selenide. These materials are very sensitive to light radiation.
MODEL GRAPH
PROCEDURE 1. 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 it‟s 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.
GRAPH It is drawn by taking distance along X – axis and current along Y – axis.
RESULT Thus the characteristic of photoelectric transducer (LDR) was determined and the graph was drawn.
TO MEASURE THE PHASE ANGLE
CIRCUIT DIAGRAM
TO MEASURE THE FREQUENCY
12. MEASUREMENT OF FREQUENCY AND PHASE ANGLE
Exp.No:……
Date:……………..
AIM To measure the frequency and phase angle using lissajious figure.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
1
CRO
-
-
1
2
Function Generator
-
-
2
3
Connecting wires
-
-
As Required
THEORY FREQUENCY MEASUREMENT To 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 MEASUREMENT It 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 shift of (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 180°and 270°.
FREQUENCY MEASUREMENT TABULATION
PROCEDURE MEASUREMENT OF PHASE ANGLE 1. Connections are made as shown in the circuit diagram 2. 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 FREQUENCY 1. 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.
GRAPH It is drawn by taking TH along X – axis and TV along Y – axis.
RESULT Thus the Phase Angle and Frequency were measured using lissajious figure.
CIRCUIT DIAGRAM
TABULATION
13. MEASUREMENT OF FREQUENCY AND AMPLITUDE USING CRO
Exp.No:……
Date:……………..
AIM To measure the frequency and amplitude using dual trace CRO for different circuit.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
1
CRO
-
-
1
2
Function Generator
-
-
2
3
Connecting wires
-
-
As Required
THEORY The 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 (Xinput) 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
PROCEDURE 1. 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.
RESULT Thus the frequency and amplitude were measured by using CRO.
RLC BRIDGE: WHEATSTONE’S BRIDGE WEIN BRIDGE CIRCUIT DIAGRAM
14. RLC BRIDGE Exp.No:……
Date:……………..
AIM To measure the value of the Resistance, Inductance and Capacitance, using RLC bridge.
APPARATUS REQUIRED
THEORY A 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.
PROCEDURE 1. 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.
TABULATION RLC bridge measurement S.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
AIM To measure the strain in the beam using Strain Gauge Trainer Kit.
APPARATUS REQUIRED
Theory: The strain gauge is an example of a ive 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 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 in the 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 Kit and 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 Manual 78 Load Cell Measurement: SENSOR 5V DC OFFSET Tp2 Gain Tp4 Tp3 Gain (0-5) V o/p P4 T4 T5 T2 T3 SG1 SG2 SG3 SG4 + DPM T6 ECE Department ECI Lab Manual 79
16. MEASUREMENT OF LOAD CELL Aim: To measure the load using Load Cell Trainer Kit and load cell . Apparatus Required: S.NO Apparatus name Quantity 1. Load Cell Trainer Kit 1 2. Load Cell 1 3. Multimeter 1 4. Load (0 - 5) Kg Theory: The load cell is an electromechanical sensor employed to measure static and dynamic forces. The device can be designed to handle a wide range of operating forces with high level of reliability, and hence is it one of the most popular transducer in industrial measurements. The load cell derives its output from the deformation of an 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 are noted 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 Manual 80 Display Readings In volts LOAD in Kg Tabulation:
Load Cell Measurement S. No. LOAD in Kg BRIDGE OUTPUT (T2, T3) mV DISPLAY READING Volts Model graph: ECE Department ECI Lab Manual 81 Result: Thus the load was measured using Load Cell Trainer Kit & Load Cell . 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 Manual 82 LVDT Measurement: Oscillation Tp6 OFFSET Tp5 Gain (0-5) V o/p P4 TP3 DPM T1 T8 T7 Buffer T6 Non – Inverting Amplifier Non – Inverting Amplifier
TP2 - OFFSET Phase Reference Amplifier T3 T2 T4 CORE LVDT AC Amplifier Half wave sync RC Filter ECE Department ECI Lab Manual 83 17. LVDT MEASUREMENT Aim: To measure the displacement using LVDT Trainer Kit. Apparatus Required: S.NO Apparatus name Quantity 1. LVDT Trainer Kit 1 2. Screw Gauge 1 3. Multimeter 1 Theory: The differential transformer is a ive inductive transformer. It is also known as a Linear Variable Differential Transformer (LVDT). The transformer consists of a single primary winding P1 and two secondary windings S1 and S2 wound on a hollow cylindrical former. The secondary windings have an equal number of turns and are identically placed on either side of the primary winding. The primary winding is connected to an ac source. An movable soft iron core slides within the hollow former and therefore affects the magnetic coupling between the primary and the two secondaries. The displacement to be measured is applied to an arm attached to the soft iron core. (Ni –iron alloy)
When the core is in its normal (null) position, equal voltages are induced in the two secondary windings. The frequency of the ac applied to the primary winding ranges from 50Hz to 20KHz. The output voltage of the secondary windings S1 is Es1 and that of secondary winding S2 is Es2. In order to convert the output from S1 to S2 into a single voltage signal, the two secondaries S1 and S2 are connected in series opposition. Hence the output voltage of the transducer is the difference of the two voltages. 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 step by step by 2mm and the corresponding readings are noted. 5. The Screw Gauge is adjusted up to the LVDT reads – 8mm. the Screw Gauge reading is noted and display reading is noted across T1 and T8. 6. The power supply is switched OFF. ECE Department ECI Lab Manual 84 Tabulation: LVDT Measurement: S. No. Screw guage Readings (mm) LVDT Display LVDT output Readings (v) Model Graph: LVDT Display Readings (mV) LVDT Output Readings (V) ECE Department ECI Lab Manual 85
Model Graph: The graph is drawn by taking LVDT reading along X – axis and display reading along Y – axis. Application: · It is widely used for measurement of displacement where linear displacement from 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 Manual 86 Measurement of Temperature: Characteristics of Thermistor: G R2 A R1 R3 Thermistor C +-D (0-30) V + Temperature in oC Platinum Specific Resistance (W cm)
Thermistor ECE Department ECI Lab Manual 87
18. THERMISTOR
AIM To study the construction, operation and characteristics of Thermistor. Result: Thus the construction, operation and characteristics of Thermistors were studied. Viva Question: 1. Where Thermistor is applied? 2. What is active transducer? 3. What is ive transducer? 4. What is negative temperature co-efficient? ECE Department ECI Lab Manual 90 Circuit Diagram: (0 – 100) mA A (0 – 30) V A (0 – 50) mA RPS 1K_ Rsh DRB ++ +ECE Department ECI Lab Manual 91 19. EXTENDING THE RANGE OF AMMETER Aim:
To extend the range of Ammeter and calibrate the Ammeter with the standard meter. Apparatus Required: S. NO APPARATUS NAME RANGE QUANTITY 1. RPS (0-30)V 1 2. Ammeter (0-100) mA (0-50) mA 1 1 3. DRB - 1 4. Bread Board - 1 5. Wires - Formula: Shunt resistance (I Im) (ImRm) Rsh = (m 1) Rm Rsh = Multiplication Factor Im I m= 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 and
the spiral springs are used as coil connectors. These can be designed for a maximum current of only 50mA and a potential drop of above 50mV. So, far measuring large current or voltage, the range of the instrument has to be extended. The common devices employed for extending the range of instruments are shunts 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 coil galvanometer. The basic movement coil is small and light. So it can carry only a very small current. When large current is to be measured, it becomes necessary to by the major part of current through shunt resistance. An ammeter shunt is merely a low resistance. This is placed in parallel with the instrument coil circuit to measure large current. ECE Department ECI Lab Manual 92 Tabulation: 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 Curve Is in m A IT in mA CORRECTION in mA ERROR in mA ECE Department ECI Lab Manual 93
Procedure: 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 and tabulated. 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 its terminals. By using this experiment, we can increase the measuring capacity of instrument. Result: Thus the range of ammeter was extended and the ammeter was calibrated with 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 THEVENIN’S THEOREM CIRCUIT DIAGRAM PRACTICAL PROOF TO FIND IL
THEORITICAL PROOF STEP 1: TO FIND RTH
RTH =
15. VERIFICATION OF THEVENIN’S THEOREM Exp.No:……
Date:……………..
AIM: To Thevenin‟s Theorem.
APPARATUS REQUIRED: Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
1
3
Voltmeter
(0-10)V
MC
1
4
Resistance
10KΩ 5.6KΩ
-
2 1
5
Bread board
-
-
1
6
Connecting wires
-
-
As Required
FORMULA:
CIRCUIT DIAGRAM
STEP 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 Thevenin‟s 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 Thevenin‟s equivalent circuit which consists of RTH and RL connected in series with VTH. 7. Now we can find IL.
RESULT: Thus the Thevenin‟s Theorem is verified.
ECE Department ECI Lab Manual
VERIFICATION OF OHM’S LAW
CIRCUIT DIAGRAM
TABULATION S.NO
Voltage across R
Current through R
V in Volts
I in (mA)
Resistance R=V/I in ohm
1. VERIFICATION OF OHM’S LAW Exp.No:……
Date:……………..
AIM To the ohm‟s law using standard resistances, Ammeter and voltmeter.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
1
3
Voltmeter
(0-50)V
1
4
Resistance
1KΩ
-
1
5
Bread board
-
-
1
6
Connecting wires
-
-
As Required
THEORY OHM’S LAW The 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 = IR Where V = Voltage (potential difference) in volts I = Current in milli Amperes R=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 ohm‟s law was verified using standard resistances, ammeter and voltmeter.
KIRCHOFF’S CURRENT LAW CIRCUIT DIAGRAM
TABULATION Sl.NO 1 2 3 4 5 6
Voltage V in volts
Current I in mA I1
I2
I3=I1+I2 mA I3
2. VERIFICATION OF KIRCHOFF’S CURRENT & KIRCHOFF’S VOLTAGE LAW Exp.No:……
Date:……………..
AIM To the Kirchoff‟s current and Kirchoff‟s voltage law by using standard Resistances, Ammeter and voltmeter.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
2
3
Voltmeter
(0-50)V
MC
2
4
Resistance
10KΩ 5KΩ
-
2 1
5
Bread board
-
-
1
6
Connecting wires
-
-
As Required
THEORY (A)KIRCHOFF’S 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 + i4 Sum of incoming current = Sum of Outgoing current (B) SECOND LAW (OR) VOLTAGE LAW The algebraic sum of voltage in a closed circuit is equal to zero. (i.e) Algebraic sum of emfs + Algebraic sum of voltage drop = 0 E = IR1 + IR2 E – IR1 – IR2 = 0
KIRCHOFF’S VOLTAGE LAW
CIRCUIT DIAGRAM
TABULATION Sl.NO 1 2 3 4 5 6
Voltage V in Current I in mA volts
Resistance in KΩ R1 R2
I(R1+R2) mA
V-I(R1+R2) in Volts
PROCEDURE KCL’s 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. the kirchoff‟s current law as I1=I2+I3. 5. Repeat the above procedure. 6. Switch off the power supply. KVL’s 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. the kirchoff‟s 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 the superposition theorem, for a common load, with two different D.C voltages.
APPARATUS REQUIRED: Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
2
1
RPS
2
Ammeter
(0-100) mA
MC
1
3
Resistance
10KΩ 5.6KΩ
-
2 1
4
Bread board
-
-
1
5
Connecting wires
-
-
As Required
FORMULA: IL = I1+I2 mA I1 = Current due to one source, mA I2 = Current due to one source, mA IL = 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
TABULATION
Sl.No
1
2
3
Source Voltages
VS1= VS2= VS1= VS2= VS1= VS2=
IA in mA
IB in mA
With Source V1
With Source
Shorted
V2 Shorted
IL=IA+IB IL in mA
in mA
(Direct Method)
(Superposition method)
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 THEVENIN’S THEOREM CIRCUIT DIAGRAM PRACTICAL PROOF TO FIND IL
THEORITICAL PROOF STEP 1: TO FIND RTH Replace the voltage sources by their internal resistances as shown below. R2
R1 100 Ohm
100 Ohm
A
A R1
B
B
R1 and R2 are in parallel therefore RTH = R1R2/(R1+R2)
RTH=………….
100 Ohm
R2 100 Ohm
4. VERIFICATION OF THEVENIN’S THEOREM Exp.No:……
Date:……………..
AIM To Thevenin‟s Theorem.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
1
3
Voltmeter
(0-10)V
MC
1
4
Resistance
10KΩ 5.6KΩ
-
2 1
5
Bread board
-
-
1
6
Connecting wires
-
-
As Required
FORMULA
CIRCUIT DIAGRAM STEP 2: TO FIND VTH R1
R2
100 Ohm
100 Ohm
A
Va 0-30 Vdc
I
B
Applying Kirchoffs voltage law we get VA-IR1-IR2-VB=0
Therefore I=…………. Also, Va-IR1-VTH
VTH=………….
Vb 0-30 Vdc
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 Thevenin‟s 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 Thevenin‟s 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:
RESULT Thus the Thevenin‟s Theorem was verified. 1.Practical value of IL=:…………… 2.Theoretical value of IL=:…………..
VERIFICATION OF NORTON’S THEOREM
CIRCUIT DIAGRAM PRACTICAL PROOF TO FIND IL
THEORITICAL PROOF STEP 1: TO FIND RN Replace the voltage sources by their internal resistances as shown below. R2
R1 100 Ohm
100 Ohm
A
A R1
B
B
R1 and R2 are in parallel therefore RN = R1R2/(R1+R2) =
RN=
100 Ohm
R2 100 Ohm
5. VERIFICATION OF NORTON’S THEOREM Exp.No:……
Date:……………..
AIM To Norton‟s theorem.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
3
Resistance
10KΩ 5.6KΩ
-
2 1
4
Bread board
-
-
1
5
Connecting wires
-
-
As Required
1
FORMULA
Where IL = Load current in (mA) IN = Norton current in (mA) RN = Norton‟s 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 (0–30)V 5.6K_ A + (0–10)mA RN 1.5K_ IL IN ECE Department ECI Lab Manual 25
Norton’s 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 across Step2: Find the short circuit current. Step3: Calculate the Norton‟s 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 Norton‟s equivalent circuit. 6. Now we can find the value of load current IL.
Tabulation for Norton’s Theorem: Load current(IL) in mA Norton’s Resistance (R N)in K_ Norton’s Current(IN)in mA Model Calculation for Norton’s Theorem: Result: Thus the Norton‟s theorem was verified.
VERIFICATION OF MAXIMUM POWER TRANSFER THEOREM
CIRCUIT DIAGRAM
TABULATION Sl.No 1 2 3 4 5 6 7 8 9 10 11 12
Load Resistance RL in KΩ
For V= Current I P= V*I Watts in mA
For V= Current I in P= V*I Watts mA
6. VERIFICATION OF MAXIMUM POWER TRANSFER THEOREM Exp.No:……
Date:……………..
AIM To , maximum power transfer theorem.
Apparatus Required: Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
1
3
Voltmeter
(0-10)V
MC
1
4
Resistance
1.5KΩ
-
3
5
Decade resistance box
-
-
1
6
Bread board
-
-
1
7
Connecting wires
-
-
As Required
THEORY The 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=RTH Maximum power transferred=
MODEL GRAPH
MODEL CALCULATION
PROCEDURE 1. 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=Observed Reading *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.No
Apparatus
Range
Name 1
Ammeter
2 3 4 5 6 7 8 1. (0-5)A MI 1 2. Ammeter (0-10)A MI 1 3. Voltmeter (0-150)V MI 1 4. Voltmeter (0-300)V MC 1 5. Wattmeter 300V,5A Dynamometer 1 6. Auto transformer - - 1 7. Transformer - - 1 8. Connecting wires - - 10
Formula Used: Iron loss = Woc
Type
Quantity
Copper loss = Wsc Total loss = Woc+Wsc Output power = capacity*cos F 100 (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 to determine no-load loss or core loss and no load current Io which is helpful in winding Ro&Xo.Supply is given to the primary winding through a wattmeter with secondary winding open circuited. The readings of the wattmeter gives the no load losses when rated voltage is applied to the primary. No load current is very small and the primary resistance is negligible.Therfore copper loss (I2R) is very small. The input to the transformer. Tabulation for Short Circuit Test: Short Circuit Test: Short circuit test can be determined by the copper loss. The copper loss occurs when the current flows through the winding .It is equal to I2R. This loss varies as the square of the load current knowing the load current and the equivalent resistance of secondary side the copper loss can be calculated by using an auto transformer the input voltage is varied from zero to small value. This is applied to the primary winding .Secondary winding is short circuited using the ammeter. Voltage is varied 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 and neglected. 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 diagram 2. 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 CALIBRATION OF AMMETER Standard Meter
Given Meter
CALIBRATION OF VOLTMETER
Given Meter Standard Meter
8. CALIBRATION OF AMMETER AND VOLTMETER Exp.No:……
Date:……………..
AIM To calibrate a D.C ammeter and a D.C voltmeter, using a standard meter. APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
2
3
Voltmeter
(0-10)V
MC
2
4
Resistance
1KΩ
-
1
5
Decade resistance box
-
-
1
6
Bread board
-
-
1
7
Connecting wires
-
-
As Required
PROCEDURE 1. The connections are made as shown in the circuit diagram 2. 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.
TABULATION CALIBRATION OF VOLTMETER Sl.No
Standard meter Reading
Given meter Reading
Error
Vs (Volts)
Ve (Volts)
Vs-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.
WHEATSTONE’S BRIDGE
CIRCUIT DIAGRAM
TABULATION SL.NO
P in Ohms
Q in Ohms
DRB (S) in Ohms
Rx= (P*S)/Q
1 2 3 4
9. WHEATSTONE’S BRIDGE Exp.No:……
Date:……………..
AIM To determine the unknown resistance value using wheatstone‟s bridge.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Voltmeter
(0-10)V
MC
1
3
Resistance
12KΩ 33KΩ
-
1 1
4
Decade Resistance Box
-
-
1
5
Bread board
-
-
1
6
Connecting wires
-
-
As Required
FORMULA Under balanced condition P*S=Q*Rx Therefore Rx= (P*S)/Q
THEORY A 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
PROCEDURE 1. 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)/Q 5. Step 3 and 4 are repeated for different value of unknown resistances. 6. Switch Off the power supply.
RESULT Thus the value of the unknown resistance is found out by using Wheat stone‟s bridge.
WIEN BRIDGE MEASURING FREQUENCY
CIRCUIT DIAGRAM
10. WEIN BRIDGE Exp.No:……
Date:……………..
AIM To determine the unknown capacitance value using wein bridge. APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
1
Function Generator
-
-
1
2
CRO
-
-
1
3
Capacitor
1µF
-
2
4
Resistance
10KΩ 5.6KΩ
-
2 1
5
Decade Resistance Box
-
-
1
6
Bread board
-
-
1
7
Connecting wires
-
-
As Required
FORMULA Frequency f =
√
By choosing R1 = R3 = R and C1=C2=C Then frequency f =
Hz
THEORY Wien 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
PROCEDURE 1. 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.
RESULT Thus the unknown frequencies were found out by using Wien‟s Bridge.
CIRCUIT DIAGRAM
TABULATION SL.NO
Distance in cm
Voltage in volts
Current in mA
1 2 3 4 5 6 7
11. PHOTO ELECTRIC TRANSDUCER
Exp.No:……
Date:……………..
AIM To determine the VI characteristics, of photoelectric transducer (LDR).
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
1
3
Voltmeter
(0-10)V
MC
1
4
Resistance
1KΩ
-
1
5
LDR
-
-
1
6
Incandescent Lamp
230V/60W
-
1
7
Bread board
-
-
1
8
Connecting wires
-
-
As Required
THEORY LDR 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 2MΩ at absolute darkness. I strong incident light its resistance value is about 10Ω only. The photoconductive materials used are Cium Sulphide, Cium Selenide or Cium Sulpho Selenide. These materials are very sensitive to light radiation.
MODEL GRAPH
PROCEDURE 1. 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 it‟s 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.
GRAPH It is drawn by taking distance along X – axis and current along Y – axis.
RESULT Thus the characteristic of photoelectric transducer (LDR) was determined and the graph was drawn.
TO MEASURE THE PHASE ANGLE
CIRCUIT DIAGRAM
TO MEASURE THE FREQUENCY
12. MEASUREMENT OF FREQUENCY AND PHASE ANGLE
Exp.No:……
Date:……………..
AIM To measure the frequency and phase angle using lissajious figure.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
1
CRO
-
-
1
2
Function Generator
-
-
2
3
Connecting wires
-
-
As Required
THEORY FREQUENCY MEASUREMENT To 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 MEASUREMENT It 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 shift of (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 180°and 270°.
FREQUENCY MEASUREMENT TABULATION
PROCEDURE MEASUREMENT OF PHASE ANGLE 1. Connections are made as shown in the circuit diagram 2. 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 FREQUENCY 1. 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.
GRAPH It is drawn by taking TH along X – axis and TV along Y – axis.
RESULT Thus the Phase Angle and Frequency were measured using lissajious figure.
CIRCUIT DIAGRAM
TABULATION
13. MEASUREMENT OF FREQUENCY AND AMPLITUDE USING CRO
Exp.No:……
Date:……………..
AIM To measure the frequency and amplitude using dual trace CRO for different circuit.
APPARATUS REQUIRED Sl. No
Apparatus Name
Range
Type
Quantity
1
CRO
-
-
1
2
Function Generator
-
-
2
3
Connecting wires
-
-
As Required
THEORY The 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 (Xinput) 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
PROCEDURE 1. 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.
RESULT Thus the frequency and amplitude were measured by using CRO.
RLC BRIDGE: WHEATSTONE’S BRIDGE WEIN BRIDGE CIRCUIT DIAGRAM
14. RLC BRIDGE Exp.No:……
Date:……………..
AIM To measure the value of the Resistance, Inductance and Capacitance, using RLC bridge.
APPARATUS REQUIRED
THEORY A 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.
PROCEDURE 1. 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.
TABULATION RLC bridge measurement S.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
AIM To measure the strain in the beam using Strain Gauge Trainer Kit.
APPARATUS REQUIRED
Theory: The strain gauge is an example of a ive 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 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 in the 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 Kit and 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 Manual 78 Load Cell Measurement: SENSOR 5V DC OFFSET Tp2 Gain Tp4 Tp3 Gain (0-5) V o/p P4 T4 T5 T2 T3 SG1 SG2 SG3 SG4 + DPM T6 ECE Department ECI Lab Manual 79
16. MEASUREMENT OF LOAD CELL Aim: To measure the load using Load Cell Trainer Kit and load cell . Apparatus Required: S.NO Apparatus name Quantity 1. Load Cell Trainer Kit 1 2. Load Cell 1 3. Multimeter 1 4. Load (0 - 5) Kg Theory: The load cell is an electromechanical sensor employed to measure static and dynamic forces. The device can be designed to handle a wide range of operating forces with high level of reliability, and hence is it one of the most popular transducer in industrial measurements. The load cell derives its output from the deformation of an 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 are noted 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 Manual 80 Display Readings In volts LOAD in Kg Tabulation:
Load Cell Measurement S. No. LOAD in Kg BRIDGE OUTPUT (T2, T3) mV DISPLAY READING Volts Model graph: ECE Department ECI Lab Manual 81 Result: Thus the load was measured using Load Cell Trainer Kit & Load Cell . 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 Manual 82 LVDT Measurement: Oscillation Tp6 OFFSET Tp5 Gain (0-5) V o/p P4 TP3 DPM T1 T8 T7 Buffer T6 Non – Inverting Amplifier Non – Inverting Amplifier
TP2 - OFFSET Phase Reference Amplifier T3 T2 T4 CORE LVDT AC Amplifier Half wave sync RC Filter ECE Department ECI Lab Manual 83 17. LVDT MEASUREMENT Aim: To measure the displacement using LVDT Trainer Kit. Apparatus Required: S.NO Apparatus name Quantity 1. LVDT Trainer Kit 1 2. Screw Gauge 1 3. Multimeter 1 Theory: The differential transformer is a ive inductive transformer. It is also known as a Linear Variable Differential Transformer (LVDT). The transformer consists of a single primary winding P1 and two secondary windings S1 and S2 wound on a hollow cylindrical former. The secondary windings have an equal number of turns and are identically placed on either side of the primary winding. The primary winding is connected to an ac source. An movable soft iron core slides within the hollow former and therefore affects the magnetic coupling between the primary and the two secondaries. The displacement to be measured is applied to an arm attached to the soft iron core. (Ni –iron alloy)
When the core is in its normal (null) position, equal voltages are induced in the two secondary windings. The frequency of the ac applied to the primary winding ranges from 50Hz to 20KHz. The output voltage of the secondary windings S1 is Es1 and that of secondary winding S2 is Es2. In order to convert the output from S1 to S2 into a single voltage signal, the two secondaries S1 and S2 are connected in series opposition. Hence the output voltage of the transducer is the difference of the two voltages. 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 step by step by 2mm and the corresponding readings are noted. 5. The Screw Gauge is adjusted up to the LVDT reads – 8mm. the Screw Gauge reading is noted and display reading is noted across T1 and T8. 6. The power supply is switched OFF. ECE Department ECI Lab Manual 84 Tabulation: LVDT Measurement: S. No. Screw guage Readings (mm) LVDT Display LVDT output Readings (v) Model Graph: LVDT Display Readings (mV) LVDT Output Readings (V) ECE Department ECI Lab Manual 85
Model Graph: The graph is drawn by taking LVDT reading along X – axis and display reading along Y – axis. Application: · It is widely used for measurement of displacement where linear displacement from 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 Manual 86 Measurement of Temperature: Characteristics of Thermistor: G R2 A R1 R3 Thermistor C +-D (0-30) V + Temperature in oC Platinum Specific Resistance (W cm)
Thermistor ECE Department ECI Lab Manual 87
18. THERMISTOR
AIM To study the construction, operation and characteristics of Thermistor. Result: Thus the construction, operation and characteristics of Thermistors were studied. Viva Question: 1. Where Thermistor is applied? 2. What is active transducer? 3. What is ive transducer? 4. What is negative temperature co-efficient? ECE Department ECI Lab Manual 90 Circuit Diagram: (0 – 100) mA A (0 – 30) V A (0 – 50) mA RPS 1K_ Rsh DRB ++ +ECE Department ECI Lab Manual 91 19. EXTENDING THE RANGE OF AMMETER Aim:
To extend the range of Ammeter and calibrate the Ammeter with the standard meter. Apparatus Required: S. NO APPARATUS NAME RANGE QUANTITY 1. RPS (0-30)V 1 2. Ammeter (0-100) mA (0-50) mA 1 1 3. DRB - 1 4. Bread Board - 1 5. Wires - Formula: Shunt resistance (I Im) (ImRm) Rsh = (m 1) Rm Rsh = Multiplication Factor Im I m= 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 and
the spiral springs are used as coil connectors. These can be designed for a maximum current of only 50mA and a potential drop of above 50mV. So, far measuring large current or voltage, the range of the instrument has to be extended. The common devices employed for extending the range of instruments are shunts 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 coil galvanometer. The basic movement coil is small and light. So it can carry only a very small current. When large current is to be measured, it becomes necessary to by the major part of current through shunt resistance. An ammeter shunt is merely a low resistance. This is placed in parallel with the instrument coil circuit to measure large current. ECE Department ECI Lab Manual 92 Tabulation: 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 Curve Is in m A IT in mA CORRECTION in mA ERROR in mA ECE Department ECI Lab Manual 93
Procedure: 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 and tabulated. 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 its terminals. By using this experiment, we can increase the measuring capacity of instrument. Result: Thus the range of ammeter was extended and the ammeter was calibrated with 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 THEVENIN’S THEOREM CIRCUIT DIAGRAM PRACTICAL PROOF TO FIND IL
THEORITICAL PROOF STEP 1: TO FIND RTH
RTH =
15. VERIFICATION OF THEVENIN’S THEOREM Exp.No:……
Date:……………..
AIM: To Thevenin‟s Theorem.
APPARATUS REQUIRED: Sl. No
Apparatus Name
Range
Type
Quantity
0-30
-
1
1
RPS
2
Ammeter
(0-100) mA
MC
1
3
Voltmeter
(0-10)V
MC
1
4
Resistance
10KΩ 5.6KΩ
-
2 1
5
Bread board
-
-
1
6
Connecting wires
-
-
As Required
FORMULA:
CIRCUIT DIAGRAM
STEP 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 Thevenin‟s 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 Thevenin‟s equivalent circuit which consists of RTH and RL connected in series with VTH. 7. Now we can find IL.
RESULT: Thus the Thevenin‟s Theorem is verified.
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