AB82 Thevenin’s Theorem Maximum Power Transfer Theorem ... · PDF fileAB82...

AB82 Thevenin’s Theorem Maximum Power Transfer Theorem

Analog LabExperiment Board

Ver. 1.0

QUALITY POLICY

To be a Global Provider of Innovative and Affordable Electronic Equipments for Technology Training by enhancing Customer Satisfaction based on Research, Modern manufacturing techniques and continuous improvement in Quality of the products and Services with active participation of employees.

An ISO 9001: 2000 company

94-101, Electronic Complex, Pardesipura INDORE-452010, India.Tel.: 91-731-2570301 Fax: 91-731-2555643Email: [email protected] Web: www.scientech.bz

http://www.scientech.bz/

mailto:[email protected]

AB82

Scientech Technologies Pvt. Ltd. 2

AB82

Thevenin’s Theorem Maximum Power Transfer TheoremAB82

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


AB82

INTRODUCTIONAB82 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 Name

AB01 Diode characteristics (Si, Zener, LED)AB02 Transistor characteristics (CB NPN)AB03 Transistor characteristics (CB PNP)AB04 Transistor characteristics (CE NPN)AB05 Transistor characteristics (CE PNP)AB06 Transistor characteristics (CC NPN)AB07 Transistor characteristics (CC PNP)AB08 FET characteristicsAB09 Rectifier CircuitsAB10 Wheatstone BridgeAB11 Maxwell’s BridgeAB14 Darlington PairAB15 Common Emitter AmplifierAB16 Common Collector AmplifierAB17 Common Base AmplifierAB18 Cascode AmplifierAB19 RC-Coupled AmplifierAB20 Direct Coupled AmplifierAB21 Class a AmplifierAB22 Class B Amplifier (push pull emitter follower)AB23 Class C Tuned AmplifierAB25 Phase Locked Loop (FM Demodulator & Frequency

Divider / Multiplier)AB28 Multivibrator ( Mono stable / Astable)AB29 F-V and V-F ConverterAB30 V-I and I-V ConverterAB31 Zener Voltage Regulator AB32 Transistor Series Voltage RegulatorAB33 Transistor Shunt Voltage Regulator


AB82

AB41 Differential Amplifier (Transistorized)AB42 Operational Amplifier (Inverting / Non-inverting /

Differentiator)AB43 Operational Amplifier (Adder/Scalar)AB44 Operational Amplifier (Integrator/ Differentiator)AB45 Schmitt Trigger and ComparatorAB51 Active filters (Low Pass and High Pass)AB52 Active Band Pass Filter AB53 Notch Filter AB54 Tschebyscheff FilterAB56 Fiber Optic Analog LinkAB65 Phase Shift OscillatorAB66 Wien Bridge OscillatorsAB67 Colpitt OscillatorAB68 Hartley OscillatorAB80 RLC Series and RLC Parallel Resonance AB81 Kirchoff’s Laws (Kirchhoff’s Current Law & Kirchhoff’s

Voltage Law)AB83 Reciprocity and Superposition TheoremAB84 Tellegen’s TheoremAB85 Norton’s theoremAB88 Diode ClipperAB89 Diode ClampersAB90 Two port network parameterAB91 Optical Transducer (Photovoltaic cell)AB92 Optical Transducer (Photoconductive cell/LDR)AB93 Optical Transducer (PhotoTransistor)AB96 Temperature Transducer (RTD & IC335)AB97 Temperature Transducer (Thermocouple)AB101 DSB Modulator and DemodulatorAB102 SSB Modulator and DemodulatorAB106 FM Modulator and Demodulator

………… and many more


AB82

THEORYThevenin’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. 1The 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


AB82

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


AB82

Fig. 2


AB82

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


AB82

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


AB82

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.


AB82

• 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.


AB82

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


AB82

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 RL 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.

LoadResistance RL

Load CurrentIL

Power dissipated PL

1. 400Ω2. 450Ω3. 500Ω4. 550Ω5. 600Ω6. 650Ω7. 680Ω8. 700Ω9. 750Ω

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 _________ .


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.


AB82

LIST OF SERVICE CENTERS

1. Scientech Technologies Pvt. Ltd.90, Electronic Complex Ph : (0731) 2570301Pardesipura, Email : [email protected] INDORE – 452010

2. Scientech Technologies Pvt. Ltd.First Floor, C-19, Ph : (011) 22157370, 22157371F.I.E., Patparganj Industrial Area, Fax : (011) 22157369DELHI – 110092 Email : [email protected]

3. Scientech Technologies Pvt. Ltd.New no.2, Old no.10, 4th street Ph : (044) 42187548, 42187549

Venkateswara nagar, Adyar Fax : (044) 42187549CHENNAI – 600025 Email : [email protected]

4. Scientech Technologies Pvt. Ltd. 202/19, 4th main street Ph : (080) 51285011 Ganganagar, Fax : (080) 51285022 BANGALORE- 560032 Email : [email protected]. Scientech Technologies Pvt. Ltd.

8,1st floor, 123-Hariram Mansion, Ph : (022) 56299457 Dada Saheb Phalke road, Fax : (022) 24168767 Dadar (East), Email : [email protected] MUMBAI –400014 6. Scientech Technologies Pvt. Ltd. 988, Sadashiv Peth, Ph : (020) 24461673 Gyan Prabodhini Lane, Fax : (020) 24482403 PUNE – 411030 Email : [email protected]. Scientech Technologies Pvt. Ltd SPS Apartment, 1st Floor Ph : +913355266800 2, Ahmed Mamoji Street, Email : [email protected]

Behind Jaiswal Hospital, Liluah, HOWRAH-711204 W.B.8. Scientech Technologies Pvt. Ltd Flat No. 205, 2nd Floor, Ph : (040) 55465643 Lakshminarayana Apartments Email : [email protected] ‘C’ wing, Street No. 17, Himaytnagar, HYDERABAD- 500029


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.


AB82 Thevenin’s Theorem Maximum Power Transfer Theorem ... · PDF fileAB82...

Documents

Transcript of AB82 Thevenin’s Theorem Maximum Power Transfer Theorem ... · PDF fileAB82...