Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

Embed Size (px)

Citation preview

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    1/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    1

    SUDHARSAN ENGINEERING COLLEGE

    ELECTRONIC CIRCUITS I

    LAB MANUAL

    SUB CODE: EC2208

    PREPARED BY

    D.RAMESH, Asst. HOD/ECE

    M.KARTHIGA, Asst. Prof/ECE

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    2/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    2

    Circuit Diagram

    CE Amplifier with Fixed Bias

    Pin Diagram

    Bottom view of BC107

    B

    E

    C

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    3/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    3

    Ex. no: 1. COMMON EMITTER AMPLIFIER WITH FIXED BIAS

    Date:

    Aim

    To design and construct BJT Common Emitter Amplifier using fixed bias .To measure the gain and to plot the frequency response and to determine the GainBandwidth product (GBW).

    Apparatus Required

    S.No Equipments / Components Range / Details Qty

    1. Power Supply (030) V 1

    2. Resistor 5.1K, 3M 1

    3. Capacitor 1 F 1

    4. Transistor BC 107 1

    5. AFO (01) MHz 1

    6. CRO (020) MHz 1

    Fixed Bias with Emitter Resistor

    The fixed bias circuit is modified by attaching an external resistor to the emitter. This resistor

    introduces negative feedback that stabilizes the Q-point. From Kirchhoff's voltage law, the voltage

    across the base resistor is

    VRb= VCC- IeRe- Vbe

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    4/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    4

    Tabulation

    VS=

    Frequency (Hz) Vo (V) Gain = Vo / Vs Gain = 20log(Vo/Vs)dB

    Model Graph

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    5/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    5

    From Ohm's law, the base current is

    Ib= VRb/ Rb.

    The way feedback controls the bias point is as follows. If Vbe is held constant and temperature

    increases, emitter current increases. However, a larger Ie increases the emitter voltage Ve= IeRe,

    which in turn reduces the voltage VRbacross the base resistor. A lower base-resistor voltage dropreduces the base current, which results in less collector current because Ic= IB. Collector current

    and emitter current are related by Ic= Iewith 1, so increase in emitter current with temperatureis opposed, and operating point is kept stable.

    Similarly, if the transistor is replaced by another, there may be a change in I C (corresponding tochange in -value, for example). By similar process as above, the change is negated and operatingpoint kept stable.

    For the given circuit,

    IB= (VCC- Vbe)/(RB+ (+1)RE).

    Merits:

    The circuit has the tendency to stabilize operating point against changes in temperature and -value.

    Demerits:

    In this circuit, to keep ICindependent of the following condition must be met:

    which is approximately the case if ( + 1 )RE>> RB.

    As -value is fixed for a given transistor, this relation can be satisfied either by keeping REverylarge, or making RBvery low.

    If REis of large value, high VCCis necessary. This increases cost as well as precautionsnecessary while handling.

    If RBis low, a separate low voltage supply should be used in the base circuit. Using twosupplies of different voltages is impractical.

    In addition to the above, RE causes ac feedback which reduces the voltage gain of theamplifier.

    Usage:The feedback also increases the input impedance of the amplifier when seen from thebase,

    which can be advantageous. Due to the above disadvantages, this type of biasing circuit is used only

    with careful consideration of the trade-offs involved.

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    6/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    6

    Design

    Choose = 250, VCC= 12V, IC= 1 mA

    By applying KVL to output side,

    VCCICRCVCE= 0

    VCC= ICRCVCE

    Assume equal drops across RCand VCEVRC= VCE= 6V, ICRC= 6V

    RC= 6V/10-3

    = 6K

    Choosing a standard value for RCas 5.1

    By applying KVL to the input side,

    VCCIBRBVBE= 0

    IB= IC/ = 1mA/250 = 4A

    RB = (VCCVBE) / IB

    =(12 0.7)/4x10-6=2.825M 3M

    Design of input capacitor

    F = 1/2hieC

    Take F = 100Hz and hie= 1.6 K

    C1 = 1/ (2X 1.6 K X 100) = 0.9F 1F

    Calculation

    Bandwidth = fH- fL

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    7/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    7

    Procedure

    1) Connect the circuit as per the circuit diagram2) Set Vin = 50mV in the signal generator. Keeping input voltage constant, vary thefrequency from 1Hz to 1MHzin regular steps.

    3) Note down the corresponding output voltage.4) Plot the graph: Gain in dB Vs Frequency in Hz.5) Calculate the Bandwidth from the Frequency response graph

    To plot the Frequency Response

    1) The frequency response curve is plotted on a semi-log scale.2) The mid frequency voltage gain is divided by 2 and these points are marked in thefrequency response curve.

    3)

    The high frequency point is called the upper 3dB point.4) The lower frequency point is called the lower 3dB point.5) The difference between the upper 3dB point and the lower 3dB point in thefrequency scale gives the bandwidth of the amplifier.

    6) From the plotted graph the bandwidth is obtained. (i.e) Bandwidth = fH- fL

    Result

    Thus a BJT Common Emitter Amplifier with fixed bias is designed and implemented and the

    frequency response curve is plotted.

    The bandwidth is found to be __________________

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    8/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    8

    Circuit Diagram

    CE Amplifier with Self Bias

    Design

    Drop across RE(VRE) is assumed to be 1V.

    Drop across VCEwith the supply of 12V is given by 12V 1V = 11V

    Assume equal drops across ICRCand VCE

    So ICRC= VRC= 11/2 = 5.5V

    Assume IC= 1 mA,

    Then RC= VRC/ IC= 5.5V / 1mA = 5.5 K

    Instead of using 5.5 K , we can use a standard value of 4.7 K

    VRE= 1V, IEIC= 1mA

    RE= VRE/IE= 1V/1mA = 1K

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    9/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    9

    Ex. no: 2. COMMON EMITTER AMPLIFIER WITH SELF BIASDate:

    Aim

    To design and construct BJT Common Emitter Amplifier using voltage bias (self bias) with

    and without bypassed emitter resistor.To measure the gain and to plot the frequency response and to determine the GainBandwidth product (GBW).

    Apparatus Required

    S.No Equipments / Components Range / Details Qty

    1. Power Supply (030) V 1

    2. Resistor 1K, 61K, 10K, 4.7K 1

    3. Capacitor 1F 1

    4. Transistor BC 107 1

    5. AFO (01) MHz 1

    6. CRO (020) MHz 1

    Theory

    Voltage divider bias (Self bias)

    A combination of fixed and self-bias can be used to improve stability and at the same time

    overcome some of the disadvantages of the other two biasing methods. One of the most widely

    used combination-bias systems is the voltage-divider type. The voltage divider is formed using

    external resistors R1and R2. The voltage across R2forward biases the emitter junction. By proper

    selection of resistors R1and R2, the operating point of the transistor can be made independent of

    . In this circuit, the voltage divider holds the base voltage fixed independent of base current provided the divider current is large compared to the base current. However, even with a fixed

    base voltage, collector current varies with temperature (for example) so an emitter resistor is

    added to stabilize the Q-point. However, to provide long-term or dc thermal stability, and at the

    same time, allow minimal ac signal degeneration, the bypass capacitor (Cbp) is placed across R3.

    If Cbp is large enough, rapid signal variations will not change its charge materially and no

    degeneration of the signal will occur.

    Merits

    Unlike above circuits, only one dc supply is necessary. Operating point is almost independent of variation. Operating point stabilized against shift in temperature.

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    10/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    10

    Tabulation

    Model Graph

    Frequency (Hz) Vo (V) Gain = Vo / Vs Gain = 20log(Vo/Vs)dB

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    11/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    11

    Procedure

    To plot the Frequency Response

    The frequency response curve is plotted on a semi-log scale.

    1) The mid frequency voltage gain is divided by 2 and these points are marked in thefrequency response curve.

    2) The high frequency point is called the upper 3dB point.3) The lower frequency point is called the lower 3dB point.4) The difference between the upper 3dB point and the lower 3dB point in the frequency scale

    gives the bandwidth of the amplifier.

    5) From the plotted graph the bandwidth is obtained. (i.e) Bandwidth = fH- fL

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    12/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    12

    Design of R1and R2

    Drop across VBE = 0.7V

    Drop across R2(VR2) = VBE+ VRE= 1.7V

    Assume R2= 10 K

    VR2= VCC.R2/ (R1+R2)

    R1= (12 X 10) / (1.7 10) = 60.5 K

    R1is assumed to be 61 K

    Design of input capacitor

    F = 1/2hieC

    Take F = 100Hz and hie= 1.6 K

    C1 = 1/ (2X 1.6 K X 100) = 0.9F 1F

    Calculation

    Bandwidth = fH- fL

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    13/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    13

    Result

    Thus a BJT Common Emitter Amplifier is designed and implemented and the frequency response

    curve is plotted.

    Bandwidth =

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    14/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    14

    Circuit diagram:

    Design:

    Since voltage amplification is done in the transistor amplifier circuit, we assume equal drops

    across VCEand Emitter Resistance RE. VRE= 6V. The quiescent current of 1mA is assumed.

    We assume a standard supply of Vcc= 12V.

    Drop across REis assumed to be VRE =6V

    Drop across VCEis VCCVRE =6VWe know that ICQ=IE,

    Now RE= VRE = 6V = 6K

    IE 1X 10-

    Design of R1& R2Drop across REis 6VDrop across VBEis 0.6VDrop across the resistance R2is VR2= VBE+ VRE=6.6VAssume R2=10K

    VCCR2= 6.6 V

    R1+ R2

    12 X 10 X 103

    = 6.6V

    R1+ 10 X 103

    120 X 103

    = R1+ 10 X 103

    6.6

    18.18 X 103= R1+ 10 X 10

    3R1=

    8 K(3.3 K + 4.7 K)

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    15/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    15

    Ex. no: 3. COMMON COLLECTOR TRANSISTOR AMPLIFIER

    Date:

    Aim:

    1.To design and construct BJT Common Collector Amplifier using voltage divider bias (self-bias).

    2. To measure the gain and to plot the frequency response & to determination of GainBandwidth Product

    Apparatus required:

    1.Transistors - BC107

    2.Regulated Power Supply -3.Audio Frequency Oscillator

    4.Resistors - 6K,8K,10K5.Capacitors - 47F

    6.CRO

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    16/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    16

    Tabular column

    Vs =

    Model graph (frequency response)

    Frequency VO Gain = VO/ VS Gain = 20 log (VO/VS)(Hz) (Volts) (dB)

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    17/48

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    18/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    18

    Circuit diagram:

    Design:

    Such a DC the ICBOof the 1st

    stage is multiplied by (+1) times and this will be input Base currentfor the 2

    ndstage. Hence the 2

    ndstage IEcurrent will be IE= (+1)

    2ICO

    For silicon transistor ICBOis the order of 10nA at room temperature =100. Now,

    IE= (101)2X 10 nA IE

    105nA0.1mA

    This current will get double with every 100rise in temperature. So to reduce the effect of ICBOthe

    1st

    stage ICBO

    flowing through the emitter of the 1st

    stage is not allowing to enter the 2nd

    stage by

    paralleling a resistor between B & E of the 2ndstage T2.So the ICBO(+1) will flow through thisresistance and a part of this current might flow through hie+ dcRE. This shunting resistance willbe the range of 1 to 4.7 K.

    Biasing Design:

    Assume R2= 10Kand Ic= 1mA.

    Since voltage amplification is done in the Darlington transistor amplifier circuit, we

    assume equal drops across VCEand load resistance RC. The ICQ= 1mA is assumed. We assumestandard supply of 12V.

    Drop across Reis assumed to be 1V. The drop across VCEwith a supply of 1.2 V is given by

    12 1 = 1V.It is equal to VRC& VCE= 5.5V RC=

    VRC= 5.5 K(4.7 K)ICDesign of

    R1& R2:Drop across REis 1V.Drop across VBE1&VBE2 is 0.6V.Drop across the resistance R2is VRE+ VBE1+ VBE2

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    19/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    19

    Ex. no: 4. DARLINGTON COMMON EMITTER AMPLIFIER

    Date:

    Aim:

    1. To design a Darlington amplifier using BJT and to measure the gain and input resistance.2. To plot the frequency response and to calculate the Gain Bandwidth Product (GBW).

    Apparatus required:

    1.Transistors - BC 107

    2.Resistors - 1K,4.7K,47K,10K (all are W)3.Capacitors - 47F, 100F4.CRO5.AFO6.RPS7.Connecting wires & Breadboard

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    20/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    20

    Tabular column:

    Vs =

    Frequency VO Gain = VO/ VS Gain = 20 log (VO/VS)

    (Hz) (Volts) (dB)

    Model graph (frequency response):

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    21/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    21

    Design continuation:

    = 1 + 0.6 + 0.6 VR2= 2.2VR2is assumed to be 10 K

    VCCR2

    = 2.2V R1+

    R2

    1.2 X 10 X 103= 2.2

    R1+ 10 X 103

    120 X 103= R1+ 10 X 10

    32.2

    54.5 X 103= R1+ 10 X 10

    3R1=

    54.5 X 10310 X 10

    3

    R1= 44.5 X 103

    R1is rounded to be 47 K

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    22/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    22

    Procedure:

    1. Connect the circuit as per the circuit diagram.2. Set VS= 5 mV using AFO.3. Keeping the input voltage constant, vary the frequency from 0 Hz to 1 MHz in regular

    steps and note down the corresponding output voltage.

    4. Plot the graph gain Vs frequency.5. Calculate bandwidth from the graph.

    Result:

    1. The frequency response curve is plotted on a log scale.2. From the graph the bandwidth isobtained Bandwidth = fH- fL=

    Specifications:

    1. Transistor - BC107, 50V1A, 3W, 300 MHz

    2. Regulated Power Supply (0- 30), 1A

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    23/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    23

    Circuit diagram:

    Pin Details

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    24/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    24

    Ex. no: 5. COMMON DRAIN AMPLIFIERDate:

    Aim:

    To design a common drain amplifier and to measure the gain, input resistance and outputresistance with and without Bootstrapping.

    Apparatus required:

    1. Transistor - BC-107

    2. Regulated Power supply - 13. Audio Frequency Oscillator - 14. Resistors - 4.7K, 2.7K, 1M5. Capacitor - 1F6. CRO7. Bread board and connecting wires

    Theory:

    Here input is applied between gate and source & output between source and Drain. Here Vs = VG+

    VGS. When a signal is applied to JFET gate via Cin,VGvaries with the signal. As VGSis fairlyconstant and Vs varies with Vi. Here output voltage follows the change in the signal voltage appliedto the gate, the circuit is also called as Source follower

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    25/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    25

    Bias design:

    VDD= 12 V, IDSS = 9.5mA, ID = 1mA, VP= -4V, Ci= 1F

    VGS= IDRS ,ID = IDSS{1-(VGS/VP)}2

    RS= 2.7K , Voltage drop across R S= 2.7V

    RD DS DD

    -RS=12-2.7=9.3V.

    Assume equal drops across VRD& VDS

    VRD= VDS= 4.65V

    RD= VRD/ID= 4.65K

    Instead of 4.65K, we can select standard value = 4.7K

    FET input is always reverse bias. So choose the value of resistance RGvery large with inThe

    range of 1Mto 10M

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    26/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    26

    Procedure:

    1. Connect the circuit as shown in the circuit diagram2. Set Vs= 50 mv in AFO3. Keeping the input voltage constant, vary the frequency from 0 Hz to1MHz in regular

    steps and note down the corresponding output voltage.

    4. Plot the graph: gain Vs Frequency5. Calculate the bandwidth from the Graph

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    27/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    27

    Tabulation

    VS=

    Frequency (Hz) VO(V) Gain = VO/ VS Gain = 20 log(VO/VS)_ dB

    Model Graph

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    28/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    28

    Result:

    Thus a common drain amplifier is designed and the gain, input resistance and output resistance

    are calculated using the measured parameters.

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    29/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    29

    Circuit DiagramDifferential Amplifier

    Common mode Configuration

    Differential mode Configuration

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    30/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    30

    Ex. no: 6. DIFFERENTIAL AMPLIFIER

    Date:

    Aim

    To construct the Differential Amplifier in

    a) Common mode andb) Differential mode, and to find the common mode rejection ratio (CMRR).

    Apparatus required

    1. Power Supply2. CRO3. Function Generator4.Transistors - BC107 -1 no

    5.Resistors - 1K - 2 nos.470 -1 no.

    Formula

    C.M.R.R = Ad/Ac

    C.M.R.R in dB = 20 log Ad/Ac

    Ad= Differential mode gainAc = Common mode gain

    Theory

    The Differential amplifier amplifies the difference between two input voltage signals. Hence it is

    called differential amplifier.V1 and V2 are input voltages, Vo is proportional to difference between

    two input signals.

    If we apply two input voltages equal in all respects then in ideal case output should be zero. But

    output voltage depends on the average common level of the inputs. Such an average level of two

    input signals is called common mode signal

    Higher the value of C.M.R.R, better the performance of the differential amplifier. To improve

    C.M.R.R we have to increase differential mode gain and decrease common mode gain

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    31/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    31

    Model Calculation

    For common mode signal

    Gain Ac = Vo / Vi

    Ac =

    For differential mode signal

    Gain Ad = Vo / Vi

    Ad =

    CMRR = 20 log (Ad / Ac)

    =

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    32/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    32

    Procedure

    1. Connections are given as per the circuit diagram2. Set Vi=5mV and note down Vo in both differential mode & common mode3. Calculate the gain for both the modes4.

    Calculate C.M.R.R

    Formulae

    For common mode signal: Gain Ac = Vo / Vi

    For differential mode signal: Gain Ad = Vo / Vi

    Common Mode Rejection Ratio: CMRR = 20 log (Ad / Ac)

    Result

    Thus a differential amplifier is constructed in both common mode and differential mode and thecorresponding gains are obtained and the CMRR is calculated.

    CMRR =

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    33/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    33

    Circuit diagram:

    Bias design:

    Since voltage amplification is done in the transistor amplifier circuit, We as equal drops

    across VCE& load resistance RE. The quiescent current of 1mA is assumed, we assume a standardsupply of 12V.

    Drop across REis assumed to be 1V,the drop across VCEwith a supply of 12V is given by 12V-

    1V=11V

    It is equal to 11/2=5.5V

    Now the voltage across the resistance REis 5.5V

    VCE= 5.5V

    VC= 5.5V IC=1mA

    RC= 5.5V/1mA = 5.5K

    Instead of using 5.5K, We can use a standard value of 4.7K. It

    is assumed that RBB/ (dc+1) = RE/ 10

    Hence RBB/ (dc+1) is neglected when compared RE.

    Hence VBB= IERE+VBE

    Hence VBEis neglected when compared to IERE

    Hence IE= VBB/ RE.

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    34/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    34

    Ex. no: 7. CLASS - A AMPLIFIER

    Date:

    Aim

    To design and construct a ClassA power amplifier.To observe the output waveform and to measure the maximum power output and to determine

    the efficiency

    Apparatus required:

    1. Transistor - BC107 - 1

    2. Resistors - 1K, 4.7K, 61K, 10K (all are W)3. Capacitors - 1f,100f(all are electrolytic)

    4. CRO - (0-20MHz)

    5. AFO - (0-1MHz)6. Regulated Power Supply7. Breadboard & Connecting Wires

    Theory:

    The Power amplifier is said to be class-A amplifier if the Q-point & the input signal are selected

    such that the output signal is obtained for a full input cycle. For this, position of the Q-point is

    approximately at the midpoint of the load line.

    For all the values of input signal, the transistor remains in the active region &never enters into cut-

    off or saturation region. When an a.c input signal is applied, the collector voltage varies

    sinusoidally hence the collector current also varies sinusoidally. The collector current flows for

    360(full cycle)of the input signal. In other words, the angle of the collector current flow is 360 i.e.

    one full cycle.

    DESIGN OF R1& R2:

    Voltage drop across RE= VRE= 1V

    Drop across VBE= 0.7V

    Drop across the resistance R2= VBE+VRE= VR2

    VR2=1.7V ; R2is assumed to be 10K

    VCCR2/ (R1+ R2) = VR2

    10*12K/(R1+10K)=1.7V

    R1=60.5V61K

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    35/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    35

    Tabular column:

    VI=

    Frequency V0 Gain = V0/ Vi Gain (dB) = 20 log V0/ Vi dB(KHz) (mV)

    Model graph:

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    36/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    36

    Procedure:

    1. Connect the circuit as per the circuit diagram.2. Set VS=10mV using AFO.

    3.Keeping the input voltage constant, vary the frequency from few Hz to 1MHz in regular steps &note down the correspondingly output voltage.

    4. Plot the graph: gain Vs frequency.5. Calculate bandwidth from the graph.

    Result:

    The class-A amplifier is designed, constructed and the output waveform is observed. The maximumpower output and the efficiency are determined.

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    37/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    37

    Circuit diagram

    Pin Diagram

    Bottom view of BC 107 / BC 178

    B

    E

    C

    3-d view

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    38/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    38

    Ex. no: 8. CLASSB POWER AMPLIFIER

    Date:

    Aim:

    To design and construct a Class B (complementary symmetry) power amplifier.To observe

    the output waveform with crossover Distortion and to measure the maximum power output andto determine the efficiency.

    Apparatus required:

    1.Power Supply - (030) V2. CRO - (020) MHz3.Function Generator - (01) MHz4.Resistor - 47 K - 1No

    1 K - 1No5.Transistors - BC 107 - 1No

    BC 178 - 1No

    Theory:

    The figure illustrates a ClassB Power Amplifier, which employs one PNP, and one NPN transistorand require no transformed. This type of amplifier uses complementary symmetry. i.e., the two

    transistor have identical characteristics but one is PNP and the other NPN.

    Its operation can be explained by referring to the figure. When the signal voltage is positive, T1(the

    NPN transistor) conducts, while T2 (the PNP transistor) is cut off. When the signal voltage is

    negative, T2conducts while T1is cut off. The load current is

    iL= ic1ic2

    some advantages of the circuit are that the transformer less operation saves on weight and cost and

    balanced pushpull input signals are not required. The disadvantage is obtaining pause of transistormatched closely enough to achieve low distortion.

    Procedure:

    1. Connect the circuit as per the diagram.2. Set VS= 50mV(say) using the signal generator.3. Keeping the input voltage constant, vary the frequency from 0Hz to 1MHz. Inregular steps. Note down the corresponding output voltage.4. Plot the graph i.e., gain (dB) Vs frequency (on a semilog graph)

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    39/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    39

    Model graph:

    Tabular column:

    VI= mV I = mA

    Frequency V0 Gain = V0/ Vi Gain (dB) = 20 log V0/ Vi dB(KHz) (mV)

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    40/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    40

    Formulae

    Result

    Thus a ClassB (complementary symmetry) power amplifier is constructed and the

    output waveforms are observed and the maximum power output and efficiency is calculated.

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    41/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    41

    Circuit diagram:

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    42/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    42

    Ex. no: 9. HALF WAVE RECTIFIER

    Date:

    Aim

    1. To design a Half wave rectifier with simple capacitor filter.2. To measure the DC voltage under load and ripple factor and to compare with calculatedvalues.

    Apparatus Required

    1. CRO - (0-20 MHz)

    2.Multimeter

    3.Diode - 1N4007

    4.Transformer - 230V / 120- 12v, 200 mA

    5.Resistor - 500-1/4W(carbon film resistors)

    6.Capacitor - 100F /25V

    7.Connecting Wires and Bread Board

    Procedure

    Half wave rectifier

    (i) Without Capacitor1.Test your transformer: Give 230v, 50Hz source to the primary coil of the transformer and

    observe the AC waveform of rated value without any distortion at the secondary of the

    transformer.

    2.Connect the half wave rectifier as shown in figure.3.Measure the Vdc&Vacusing DC and AC Voltmeters.

    4. Calculate the Ripple factor r = Vac/Vdc

    Note:The rectifier output consists of both AC & DC components. To block DC component100f

    (Electrolytic) Condenser is used.

    5. Compare the theoretical ripple factor with the practical ripple factor.

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    43/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    43

    Model Graph

    VI(v)

    T(m sec)

    Input Wave Form

    Vo(V) With filter

    Without filter

    T(m sec)

    Half Wave Rectifier Output

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    44/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    44

    (ii) With Capacitor1. Connect the half wave rectifier with filter circuit as shown in fig.2. Assume r= 10% of ripple peak-to-peak voltage for R= 500. Calculate C using theformula r = 1/23fRC3. Connect CRO across load.4. Keep the CRO switch in ground mode and observe the horizontal line and adjust it tothe X-axis.

    5. Switch the CRO into DC mode and observe the waveform.

    Result

    Thus the Full wave rectifier is designed with and without capacitor filter and the

    corresponding dc output voltages and the ripple factors are measured and verified with the

    theoretical values.

    Ripple Factor

    Theoretical Practical

    Specifications:

    1. Diode 1N4007 (700V- PIV, Idc= 1A)

    2. RPS (0-30),1A

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    45/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    45

    Circuit diagram:

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    46/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    46

    Ex. no: 10. FULL WAVE RECTIFIER

    Date:

    Aim

    1. To design a Full wave rectifier with and without simple capacitor filter.2. To measure the DC voltage under load and ripple factor and to compare withcalculated

    Apparatus Required

    1. CRO - (0-20 MHz)

    2.Multimeter -

    3.Diode - 1N4007

    4.Transformer - 230V / 120- 12v, 200 mA

    5.Resistor - 500-1/4W(carbon film resistors)

    6.Capacitor - 100F /25V

    7.Connecting Wires and Bread Board

    Procedure

    Full wave rectifier

    (i) Without Capacitor1. Test your transformer: Give 230v, 50Hz source to the primary coil of the transformerand observe the AC waveform of rated value without any distortion at the secondary of the

    transformer.

    2. Connect the full wave rectifier as shown in figure.3. Measure the Vdc&Vacusing DC and AC Voltmeters.4. Calculate the Ripple factorr = Vac/Vdc

    Note:The rectifier output consists of both AC&DC components. To block DC component

    100f (Electrolytic) Condenser is used.

    5. Compare the theoretical ripple factor with the practical ripple factor.

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    47/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    47

    Model graph:

    VI(v)

    t (m sec)

    Input Wave Form

    VO(V)With filter

    Without filter

    t (m sec)

    Full Wave Rectifier Output

  • 8/12/2019 Files_ECE_Manual_III_EC2208 - Electronics Circuit 1 Laboratory

    48/48

    EC2208 Electronic circuits I- Sudharsan Engineering college

    (ii) With capacitor:1. To plot ripple peak-to-peak voltage Vs. Idc to choose C a ripple factor of 0.15 isassumed.

    2. To get a variable load resistance a number of 500, 5W of resistance are to beconnected in parallel. Hence Idc= Vdc/( N X 500). Where N is number of 500resistances

    connected in parallel.

    3. Plot the graph IdcVs ripple peak to peak.4. The above steps are repeated for the various values of capacitance.

    Result

    Thus the Full wave rectifier is designed with and without capacitor filter and the corresponding dc

    output voltages and the ripple factors are measured and verified with the theoretical values.

    Ripple Factor

    Theoretical Practical

    Specifications:

    1. Diode 1N4007 (700V- PIV, Idc= 1A)

    2 RPS (0-30) 1A