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AB16COMMON COLLECTOR
AMPLIFIER
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: 91-731-2555643
AB16
COMMON COLLECTOR AMPLIFIER
AB16
TABLE OF CONTENTS
1.Introduction 4
2. Theory 6
3.Experiment 12
To study the Common Collector Amplifier (NPN) and to evaluate :
a. Operating Point of the Common Collector AmplifierVoltage gain of the Amplifier AV. b. Input and output impedance of Amplifier. c. Current gain of Amplifier.
4.Datasheet 14
5.Warranty 16
6.List of Service Centers 17
7.List of Accessories with AB16 18
8. Notes 19
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AB16
INTRODUCTION
AB16 is a compact, ready to use Common Collector Amplifier experiment board. This is useful for students to understand the functionality of common collector amplifier and to study various operational parameters of an transistor Amplifier. 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, potentiometer.
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 Bridge AB11 Maxwell’s BridgeAB12 De Sauty’s BridgeAB13 Schering BridgeAB14 Darlington PairAB17 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 RegulatorAB35 DC Ammeter
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AB39 Instrumentation AmplifierAB41 Differential Amplifier (Transistorized)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 Filter AB56 Fiber Optic Analog LinkAB57 Owen’s BridgeAB58 Anderson’s BridgeAB59 Maxwell’s Inductance BridgeAB64 RC – Coupled Amplifier with FeedbackAB65 Phase Shift OscillatorAB66 Wien Bridge OscillatorsAB67 Colpitt OscillatorAB68 Hartley OscillatorAB80 RLC Series and RLC Parallel Resonance AB82 Thevenin’s and Maximum power Transfer TheoremAB83 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 DemodulatorAB110 Log and Antilog AmplifierAB111 Crystal Oscillator (1 MHz)AB112 Peak DetectorAB113 Voltage Follower & Precision RectifierAB115 Op-Amp Oscillator (Sine / Cosine)AB116 Sample and Hold Circuit
………… and many more
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THEORY
Amplification is the process of increasing the strength of signal. An Amplifier is a device that provides amplification (the increase in current, voltage or power of signal) without appreciably altering the original signal.
A Bipolar transistor is frequently used as an amplifier. A bipolar transistor is a current amplifier, having three terminals Emitter, Base, Collector. A small current into base controls a large current flow from the collector to emitter. The large current flow is independent of voltage across the transistor from collector to emitter. This makes it possible to obtain a large amplification of voltage by taking the output voltage from a resistor in series with the collector.
Transistor can be used as an Amplifier in three configurations:
1. Common Base
2. Common Emitter
3. Common Collector
Common Collector Configuration :
In this arrangement, the input signal is applied between base and collector and the output is taken from the emitter and collector. In this arrangement input current is base current and output current is emitter current.
Fig. 1
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Current relations in CC configurations
IE = IC + IB
IE = γ * IB + γ * ICBO
γ = IE / IB
WhereIB = Base current (input current)IC = Collector currentIE = Emitter current (output current)ICEO = current through collector to emitter when base is open. γ = current amplification in CC configuration.
Operation of Common Collector amplifier :
In order to get faithful amplification, the transistor is properly DC biased. The purpose of DC biasing is to obtain a certain DC Emitter current (IC) at a certain DC Emitter voltage (VEC). These values of current and voltage are called operating point (Quiescent point). To obtain DC operating point some biasing methods are used called biasing circuits. These biasing arrangements should be such as to operate the transistor in Active region.
The Most commonly used Biasing circuits is voltage divider method. In this method two resistances R1 and R2 are connected across the supply voltage VCC and provide proper biasing. A voltage divider formed by R1 and R2, and the voltage drop across R2 forward biased the base emitter junction this causes the base current and hence collector current flows in zero signal condition. Resistance RE provides stabilization.
V2 = VCC * R2 / (R1 + R2)
V2 = VBE + VE
V2 = VBE + IER
IE = (V2 - VBE) / RE
IE is approx. equal to IC.
IC = (V2 - VBE) / RE
VCE = VCC - IC (RC + RE)
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AB16
Fig. 2
This method is widely used because operating point of transistor can be made almost independent of beta (β) and provides good stabilization of operating point.
If this circuit is used to amplify AC voltages, some more components must be added to it.
Coupling Capacitors (C1 &C3): They are used to pass AC input signal and block the DC voltage from the preceding circuit. This prevents DC in the circuitry on the left of coupling capacitor from affecting the bias on transistor. The coupling capacitor also blocks the bias of transistor from reaching the input signal source. It is also called blocking capacitor. Bypass Capacitors (C2): It bypasses all the AC current from the emitter to the ground. If the capacitor C2 is not put in the circuit, the AC voltage developed across RE will affect the input AC voltage, such a feedback is reduced by putting the capacitor C2.
RE: It represents the load resistance is connected at the output.
In this amplifier input signal is injected in to base-collector circuit and output signal is taken out from the emitter-collector circuit, When the output is taken from emitter terminal of transistor this network is referred as Emitter Follower or common collector amplifier. In this amplifier output voltage is always less than the input signal, and output voltage is in phase with the input voltage. The fact that output voltage follows the magnitude
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of input voltage with an in-phase relationship accounts for the terminology "Emitter Follower".
When positive half cycle of the signal is applied then,
1. Forward biased is increased, since Vbe is positive w.r.t. collector ie. Ground.
2. Base current is increased,
3. Emitter current is increased,
4. Drop across Re is increased,
5. Hence output voltage is increased; consequently positive half-cycle of the output is obtained. I.e. input and output are in phase with each other.
Fig. 3
Operating Parameter of Common collector amplifier :
Voltage Gain :
The ratio or Output Voltage (Vo) to the input voltage (Vi) is known as voltage amplification or voltage gain of amplifier.
Voltage Gain (AV) = VO / Vi
Input Impedance :
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It is the ratio of Input voltage (Vin) to input current (Ii)
Zin = Vin / Ii
To measure the input impedence a known resistor (Rs) is placed in series before the input coupling capacitor and the impedence could be calculated using the equation
Zin = Rs / (Av/Av`- l)
Where Av = voltage gain without the resistor (Rs)Av` = voltage gain with the resistor (Rs)
Fig. 4
Output Impedence : It is the ratio of Output voltage (Vout) to Output Current (Io).
Zout = Vout / Io
To measure the Output impedence a known resistor (Rs) is placed from output to ground and the output impedence could be calculated using the equation
Zout = (Av / Av`-l) * Rs
Where Av = voltage gain without the resistor (Rs) Av` = voltage gain with the resistor (Rs)
Current gain :
It is the ratio of Output current ( Io) to Input current (Ii).
Ai = IO / Ii
The Current gain could be calculated using the equation
Ai = - Av * Zin / RL
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Characteristics of Common Collector Amplifier :
1. It produces no phase reversal, i.e., input and output signals are in phase with each other.
2. It has voltage gain of less than 1.
3. It has very high input impedance.
4. It has low output impedance.
5. It has high current gain (β + 1).
Comparisons of Amplifiers Configurations :
Characteristic
Type of Amplifier Circuit
Common Base
CommonEmitter
CommonCollector
Phase reversal No Yes No
Voltage Gain High Highest Nearly Unity
Input Impedance Lowest Moderate Highest
Output Impedance
Highest Moderate Lowest
Current Gain Nearly unit High (β) Highest (β + 1 )
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EXPERIMENT
Objective :
To study the Common Collector Amplifier and to evaluate –
Operating Point, Voltage gain (AV), input and output impedance, current gain of amplifier.
Apparatus required :
1. Analog board of, AB16.
2. DC power supply +12V external source or ST2612 Analog Lab.
3. Digital Multimeter
4. 2 mm patch cords.
Circuit diagram :
Circuit used to study Common Collector Amplifier is shown in Fig 5.
Fig. 5
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Procedure :
1. Connect test point 2 and test point 3, test point 4 and test point 5, test point 6 and test point 7, using 2mm patch cords.
2. Connect +12V dc power supply at their indicated position from external source or ST2612 Analog Lab.
3. Switch ON the power supply.
4. For the measurement of Quiescent Point measure the VEC by connecting voltmeter between test point 4 and test point 6. Measure Emitter current (IE) by connecting ammeter between test point 6 and test point 7.
5. Connect a sinusoidal signal of 10mV (p-p) at 25KHz frequency at the Test point 1 (Input of amplifier).
6. Observe the amplified output on oscilloscope by connecting test point 8 (output of amplifier) to oscilloscope.
7. Calculate Voltage gain of amplifier. Connect Load resistor of 1K ohms at the output and find the voltage gain of amplifier with load resistor.
8. Calculate input impedance, output impedance, current gain of amplifier using the mentioned formulas with resistance 1 K.
Result :
Operating Point of the Common collector amplifier
IC = ______________mA
VEC =______________V
Voltage gain of the amplifier AV =________________
Input impedance of amplifier Zin =________________
Output Impedance of amplifier Zout =________________
Current gain of amplifier Ai =________________
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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.
DISPATCH PROCEDURE FOR SERVICEShould 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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LIST OF SERVICE CENTERS
1. Scientech Technologies Pvt. Ltd.90, Electronic Complex Ph: (0731) 5202959Pardesipura, Email: [email protected] INDORE – 452010
2. Scientech Technologies Pvt. Ltd. Ph.: (011) 26513912, 26864943First Floor, 14, Uday Park, Fax: (011) 26864943.NEW DELHI – 110049 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. Ph.: (022) 56299457 8,1st floor, 123-Hariram Mansion, Fax: (022) 24168767 Dada Saheb Phalke road, Email: [email protected] Dadar (East), 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 Ph.: (040) 55465643
Flat No. 205, 2nd Floor, Email: [email protected] Apartments‘C’ wing, Street No. 17,Himaytnagar, HYDERABAD- 500029
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LIST OF ACCESSORIES
1. 2mm Patch cord (red) ................................................................1 Nos.
2. 2mm Patch cord (black) .............................................................3 Nos.
3. 2mm Patch cord (blue) ...............................................................5 Nos.
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