AB82
Thevenin’s Theorem
Maximum Power Transfer Theorem
Analog Lab
Experiment Board
Ver. 1.0
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AB82
Scientech Technologies Pvt. Ltd.
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AB82
Thevenin’s Theorem Maximum Power Transfer Theorem
AB82
TABLE OF CONTENTS
1.Introduction
4
2. Theory
6
3.Experiments
•
Experiment 1
To verify Thevenin’s Theorem.
9
•
Experiment 2
To verify Maximum Power Transfer Theorem.
12
4.Warranty
14
5.List of Service Centers
15
6.List of Accessories with AB82
16
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AB82
INTRODUCTION
AB82 is a compact, ready to use Thevenin’s Theorem Maximum Power
Transfer Theorem experiment board. This is useful for students to study
Thevenin’s Theorem and Maximum Power Transfer Theorem. It can be
used as stand alone unit with external DC power supply or can be used with
SCIENTECH Analog Lab ST2612 which has built in DC power supply,
AC power supply, function generator, modulation generator, continuity
tester, toggle switches and potentiometer.
List of Boards :
Model
AB01
AB02
AB03
AB04
AB05
AB06
AB07
AB08
AB09
AB10
AB11
AB14
AB15
AB16
AB17
AB18
AB19
AB20
AB21
AB22
AB23
AB25
AB28
AB29
AB30
AB31
AB32
AB33
Name
Diode characteristics (Si, Zener, LED)
Transistor characteristics (CB NPN)
Transistor characteristics (CB PNP)
Transistor characteristics (CE NPN)
Transistor characteristics (CE PNP)
Transistor characteristics (CC NPN)
Transistor characteristics (CC PNP)
FET characteristics
Rectifier Circuits
Wheatstone Bridge
Maxwell’s Bridge
Darlington Pair
Common Emitter Amplifier
Common Collector Amplifier
Common Base Amplifier
Cascode Amplifier
RC-Coupled Amplifier
Direct Coupled Amplifier
Class a Amplifier
Class B Amplifier (push pull emitter follower)
Class C Tuned Amplifier
Phase Locked Loop (FM Demodulator & Frequency
Divider / Multiplier)
Multivibrator ( Mono stable / Astable)
F-V and V-F Converter
V-I and I-V Converter
Zener Voltage Regulator
Transistor Series Voltage Regulator
Transistor Shunt Voltage Regulator
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AB82
AB41
AB42
AB43
AB44
AB45
AB51
AB52
AB53
AB54
AB56
AB65
AB66
AB67
AB68
AB80
AB81
AB83
AB84
AB85
AB88
AB89
AB90
AB91
AB92
AB93
AB96
AB97
AB101
AB102
AB106
Differential Amplifier (Transistorized)
Operational Amplifier (Inverting / Non-inverting /
Differentiator)
Operational Amplifier (Adder/Scalar)
Operational Amplifier (Integrator/ Differentiator)
Schmitt Trigger and Comparator
Active filters (Low Pass and High Pass)
Active Band Pass Filter
Notch Filter
Tschebyscheff Filter
Fiber Optic Analog Link
Phase Shift Oscillator
Wien Bridge Oscillators
Colpitt Oscillator
Hartley Oscillator
RLC Series and RLC Parallel Resonance
Kirchoff’s Laws (Kirchhoff’s Current Law & Kirchhoff’s
Voltage Law)
Reciprocity and Superposition Theorem
Tellegen’s Theorem
Norton’s theorem
Diode Clipper
Diode Clampers
Two port network parameter
Optical Transducer (Photovoltaic cell)
Optical Transducer (Photoconductive cell/LDR)
Optical Transducer (PhotoTransistor)
Temperature Transducer (RTD & IC335)
Temperature Transducer (Thermocouple)
DSB Modulator and Demodulator
SSB Modulator and Demodulator
FM Modulator and Demodulator
………… and many more
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AB82
THEORY
Thevenin’s Theorem :
Any two-terminal, linear bilateral dc network can be replaced by an
equivalent circuit consisting of a voltage source and a series resistor
Fig. 1
The Thevenin equivalent circuit provides equivalence at the terminals
only − the internal construction and characteristics of the original network
and the Thevenin equivalent are usually quite different.
This theorem achieves two important objectives:
Provide a way to find any particular voltage or current in a linear network
with one, two, or any other number of sources.
We can concentrate on a specific portion of a network by replacing the
remaining network with an equivalent circuit.
Sequence to proper value of RTh and ETh
Preliminary :
1.
Remove that portion of the network across which the Thevenin
equation circuit is to be found. In the fig. 2, this requires that the load
resistor RL be temporarily removed from the network.
2.
Mark the terminals of the remaining two-terminal network. (The
importance of this step will become obvious as we progress through
some complex networks)
RTh :
3.
Calculate RTh by first setting all sources to zero (voltage sources are
replaced by short circuits, and current sources by open circuits) and
then finding the resultant resistance between the two marked
terminals. (If the internal resistance of the voltage and/or current
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sources is included in the original network, it must remain when the
sources are set to zero.)
ETh:
4.
Calculate ETh by first returning all sources to their original position
and finding the open-circuit voltage between the marked terminals.
(This step is invariably the one that will lead to the most confusion
and errors. In all cases, keep in mind that it is the open-circuit
potential between the two terminals marked in step 2.)
Conclusion :
5.
Draw the Thevenin equivalent circuit with the portion of the circuit
previously removed replaced between the terminals of the equivalent
circuit. This step is indicated by the placement of the resistor RL
between the terminals of the Thevenin equivalent circuit.
Experimental Procedures :
Two popular experimental procedures for determining the parameters of the
Thevenin equivalent network:
Direct Measurement of ETh and RTh
For any physical network, the value of ETh can be determined
experimentally by measuring the open-circuit voltage across the load
terminals.
The value of RTh can then be determined by completing the network with a
variable resistance RL
Measuring VOC and ISC :
The Thevenin voltage is again determined by measuring the open-circuit
voltage across the terminals of interest; that is, ETh = VOC. To determine RTh,
a short-circuit condition is established across the terminals of interest and
the current through the short circuit ISC is measured with an ammeter
Using Ohm's law : RTh = VOC / ISC
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Fig. 2
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Maximum Power Transfer Theorem :
The Maximum Power Transfer Theorem states that when the load resistance
is equal to the source's internal resistance, maximum power will be
developed in the load. Since most low voltage DC power supplies have a
very low internal resistance (10 ohms or less) great difficulty would result
in trying to effect this condition under actual laboratory experimentation. If
one were to connect a low value resistor across the terminals of a 10 volt
supply, high power ratings would be required, and the resulting current
would probably cause the supply's current rating to be exceeded. In this
experiment, therefore, the student will simulate a higher internal resistance
by purposely connecting a high value of resistance in series with the DC
voltage supply's terminal. Refer to fig. 1. The terminals (a & b) will be
considered as the power supply's output voltage terminals. The student will
use a potentiometer as a variable size of load resistance. For various settings
of the potentiometer representing RL, the load current and load voltage will
be measured. The power dissipated by the load resistor can then be
calculated. For the condition of RL = Ri, the student will verify by
measurement that maximum power is developed in the load resistor.
In other word
The maximum amount of power will be dissipated by a load resistance
when load resistance is equal to the Thevenin/Norton resistance of the
network supplying the power. If the load resistance is lower or higher than
the Thevenin/Norton resistance of the source network, its dissipated power
will be less than maximum.
This is essentially what is aimed for in stereo system design, where speaker
“impedance” is matched to amplifier “impedance” for maximum sound
power output. Impedance, the overall opposition to AC and DC current, is
very similar to resistance, and must be equal between source and load for
the greatest amount of power to be transferred to the load. Load impedance
that is too high will result in low power output. A load impedance that is too
low will not only result in low power output, but possibly overheating of the
amplifier due to the power dissipated in its internal (Thevenin or Norton)
impedance.
Taking our Thevenin equivalent example circuit, the Maximum Power
Transfer Theorem tells us that the load resistance resulting in greatest
power dissipation is equal in value to the Thevenin resistance (in this case,
680 Ω) :
With this value of load resistance, the dissipated power will be Maximum
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EXPERIMENT 1
Objective :
To verify Thevenin’s Theorem.
Apparatus required :
1.
Analog board of AB82.
2.
DC power supplies +12V, +15V from external source or ST2612
Analog Lab.
3.
Digital multimeter.
4.
2 mm patch cords.
Circuit diagram :
Circuit used to study Thevenin’s is shown in Fig 3.
Fig. 3
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Procedure :
•
•
Connect +12V, +5V dc power supplies at their indicated position
from external source or ST2612 Analog Lab.
To measure practical value of Thevenin's equivalent voltage VTH of
given circuit, proceed as follows :
1.
Connect a 2mm patch cord between test point 1 & 2.
2.
As we want to replace left side of Load resistance by its Thevenin's
equivalent circuit. Disconnect load resistance by removing Patch
cord between test point 3 & 4.
3.
Measure voltage between test point 3 & 5.
4.
It is the required value of Thevenin's equivalent voltage.
•
To measure Theoretical value of Thevenin's equivalent voltage VTH
of given circuit, proceed as follows :
1.
Determine the value of current I flowing through 511E resistor with
the help of basic current laws.
2.
Product of current I and resistance value 511 is the required
theoretical value of VTH.
3.
Compare theoretical and practical value of Thevenin;s equivalent
voltage VTH
•
To measure practical value of Thevenin's equivalent Resistance RTH
of given circuit, proceed as follows :
1.
Disconnect the 2mm patch cord between test point 1 & 2.
2.
As we want to replace left side of Load resistance by its Thevenin' s
equivalent circuit. Disconnect load resistance by removing Patch
cord between test point 3 & 4.
3.
Connect test point 2 & ground so as to replace source by its internal
resistance (Assuming it negligible)
4.
Measure resistance between test point 3 & 5.
5.
It is the required value of Thevenin's equivalent resistance RTH.
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•
•
•
Measure Theoretical value of Thevenin’s equivalent resistance RTH
between test point 3 & 5 of the given circuit by using fundamentals
of resistance in series and parallel.
Compare theoretical and practical value of Thevenin’s equivalent
resistance RTH.
To compare the given circuit with its Thevenin’s equivalent circuit
proceed as follows:
1.
Connect a 2mm patch cord between test point 1 & 2.
2.
Set the value of Load resistance of given circuit and its equivalent
circuit equal to 500Ω, 600Ω, 700Ω… 1K.
3.
Connect an ammeter between test point 3 & 4 to measure current
flowing through load resistance of given circuit.
4.
Connect an ammeter between test point 6 & 7 to measure current
flowing through load resistance of Thevenin’s equivalent circuit.
5.
Compare current flowing through both of the load resistance.
Result :
1.
Theoretical value of Thevenin’s equivalent voltage VTH = __________
2.
Practical value of Thevenin’s equivalent voltage VTH = ____________
3.
Theoretical value of Thevenin’s equivalent resistance RTH = ________
4.
Practical value of Thevenin's equivalent resistance RTH = __________
5.
(Yes/No) _________, The value of current flowing through the load
resistance in both of the cases is approximately equal. Hence
Thevenin’s theorem is verified.
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EXPERIMENT 2
Objective :
To verify Maximum Power Transfer Theorem.
Apparatus required :
1.
Analog board of AB82.
2.
DC power supplies +12V, +5V from external source or ST2612
Analog Lab.
3.
Digital multimeter.
4.
2 mm patch cords.
Circuit diagram :
Circuit used to study Maximum Power Transfer Theorem is shown in Fig 3.
Fig. 3
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Procedure :
•
Connect + 12V, +5V dc power supplies at their indicated position
from external source or ST2612 Analog Lab.
1.
Set a value of load resistance R L at some lower value (100Ω, 200Ω,
300Ω…… 600Ω, 680Ω, 700Ω) than Thevenin’s resistance by
keeping ohm meter between test point 7 and ground.
2.
Connect a multi-meter between test point 6 & 7 as an ammeter to
measure current flowing through Load resistance RL.
3.
Determine the product of IL* RL, the power dissipated for this value
of Load resistance.
4.
Record the value of Load Resistor RL, Current flowing through Load
resistance IL, Power dissipated PL in an observation table as shown
below :
Sr.
No.
1.
2.
3.
4.
5.
6.
7.
8.
9.
Load
Resistance RL
400Ω
450Ω
500Ω
550Ω
600Ω
650Ω
680Ω
700Ω
750Ω
Load Current
IL
Power dissipated PL
Result :
________(Yes/No), the maximum amount of power will be dissipated by a
load resistance when that load resistance is equal to the Thevenin resistance
of the network supplying the power and the value of Maximum power
dissipated is found equal to _________ .
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AB82
WARRANTY
1) We guarantee the instrument against all manufacturing defects during
24 months from the date of sale by us or through our dealers.
2) The guarantee covers manufacturing defects in respect of indigenous
components and material limited to the warranty extended to us by the
original manufacturer, and defect will be rectified as far as lies within
our control.
3) The guarantee will become INVALID.
a) If the instrument is not operated as per instruction given in the
instruction manual.
b) If the agreed payment terms and other conditions of sale are not
followed.
c) If the customer resells the instrument to another party.
d) Provided no attempt have been made to service and modify the
instrument.
4) The non-working of the instrument is to be communicated to us
immediately giving full details of the complaints and defects noticed
specifically mentioning the type and sr. no. of the instrument, date of
purchase etc.
5) The repair work will be carried out, provided the instrument is
dispatched securely packed and insured with the railways. To and fro
charges will be to the account of the customer.
DESPATCH PROCEDURE FOR SERVICE
Should it become necessary to send back the instrument to factory please
observe the following procedure:
1) Before dispatching the instrument please write to us giving fully details
of the fault noticed.
2) After receipt of your letter our repairs dept. will advise you whether it
is necessary to send the instrument back to us for repairs or the
adjustment is possible in your premises.
Dispatch the instrument (only on the receipt of our advice) securely packed
in original packing duly insured and freight paid along with accessories and
a copy of the details noticed to us at our factory address.
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AB82
LIST OF SERVICE CENTERS
1. Scientech Technologies Pvt. Ltd.
90, Electronic Complex
Pardesipura,
INDORE – 452010
2. Scientech Technologies Pvt. Ltd.
First Floor, C-19,
F.I.E., Patparganj Industrial Area,
DELHI – 110092
3. Scientech Technologies Pvt. Ltd.
New no.2, Old no.10, 4th street
Venkateswara nagar, Adyar
CHENNAI – 600025
4. Scientech Technologies Pvt. Ltd.
202/19, 4th main street
Ganganagar,
BANGALORE- 560032
5. Scientech Technologies Pvt. Ltd.
8,1st floor, 123-Hariram Mansion,
Dada Saheb Phalke road,
Dadar (East),
MUMBAI –400014
6. Scientech Technologies Pvt. Ltd.
988, Sadashiv Peth,
Gyan Prabodhini Lane,
PUNE – 411030
7. Scientech Technologies Pvt. Ltd
SPS Apartment, 1st Floor
2, Ahmed Mamoji Street,
Behind Jaiswal Hospital,
Liluah, HOWRAH-711204 W.B.
8. Scientech Technologies Pvt. Ltd
Flat No. 205, 2nd Floor,
Lakshminarayana Apartments
‘C’ wing, Street No. 17,
Himaytnagar,
HYDERABAD- 500029
Scientech Technologies Pvt. Ltd.
Ph : (0731) 2570301
Email : info@scientech.bz
Ph : (011) 22157370, 22157371
Fax : (011) 22157369
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Ph : (044) 42187548, 42187549
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Ph : +913355266800
Email : kolkata@scientech.bz
Ph : (040) 55465643
Email : hyd@scientech.bz
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AB82
LIST OF ACCESSORIES
1.
2mm Patch cord (red) .........................................................2 Nos.
2.
2mm Patch cord (black) ......................................................2 Nos.
3.
2mm Patch cord (blue) ........................................................2 Nos.
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