EDC LAB MASTER MANUAL AY 22-23.doc

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1. ELECTRONIC DEVICES AND CIRCUITS LAB B.Tech.1-Sem R 20
CMR ENGINEERING COLLEGE DEPARTMENT OF ECE
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List of Experiments
Verify any twelve experiments in H/W Laboratory
1. PN Junction diode characteristics A) Forward bias B) Reverse bias.
2. Zener diode characteristics and Zener as voltage Regulator
3. Full Wave Rectifier with & without filters
4. Input and output characteristics of BJT in CE Configuration
5. Input and output characteristics of FET in CS Configuration
6. Common Emitter Amplifier Characteristics
7. Common Base Amplifier Characteristics
8. Common Source amplifier Characteristics
9. Measurement of h-parameters of transistor in CB, CE, CC configurations
10. Switching characteristics of a transistor
11. SCR Characteristics.
12. Types of Clippers at different reference voltages
13. Types of Clampers at different reference voltages
14. The steady state output waveform of clampers for a square wave input.

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1. PN JUNCTION DIODE CHARACTERISTICS
A)FORWARD BIAS B) REVERSE BIAS

AIM: 1. To Plot the Volt Ampere Characteristics of PN Junction Diode under
Forward and Reverse Bias Conditions.

2. To find the Cut-in voltage, Static Resistance, Dynamic Resistance for Forward Bias

& Reverse Bias

APPARATUS:

S.No Name Range / Value Quantity

1 DC Regulated Power Supply 0 – 30 volts 1
2 Diode 1N 4007 1
3 Resistor 1K 1
4 D.C Ammeters 0–20mA, 0–200A Each 1
5 D.C Volt meters 0–2V, 0–20V Each 1
6 Bread Board - 1 Set
7 connecting wires - 1 Set

THEORY:-
A p-n junction diode conducts only in one direction. The V-I characteristics of the diode
are curve between voltage across the diode and current through the diode. When external voltage
is zero, circuit is open and the potential barrier does not allow the current to flow. Therefore,
the circuit current is zero. When P-type (Anode is connected to +ve terminal and n- type
(cathode) is connected to –ve terminal of the supply voltage, is known as forward bias. The
potential barrier is reduced when diode is in the forward biased condition. At some forward
voltage, the potential barrier altogether eliminated and current starts flowing through the diode
and also in the circuit. The diode is said to be in ON state. The current increases with increasing
forward voltage.
When N-type (cathode) is connected to +ve terminal and P-type (Anode) is connected –
ve terminal of the supply voltage is known as reverse bias and the potential barrier across the
junction increases. Therefore, the junction resistance becomes very high and a very small current
(reverse saturation current) flows in the circuit. The diode is said to be in OFF state.

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FORWARD BIAS:-




REVERSE BIAS:-


PROCEDURE:

FORWARD BIAS CHARACTERISTICS :

1. Connect the Circuit as per the Circuit Diagram on the bread board.

2. Switch on the Regulated Power Supply and slowly increase the source voltage.
Increase the Diode Current in steps of 2mA and note down the corresponding
voltage across the PN junction Diode under forward Bias condition as per table
given below.

3. Take the readings until a Diode Current of 30mA.
4. Repeat the same by using Ge Diode instead of Si Diode.
5. Plot the graph VF versus IF on the graph Sheet in the 1
st
quadrant as in Fig.

6. From the graph find out the Static & Dynamic forward Bias resistance of the
diode
R = VF , rac = VF .



I
F IF

7. Observe and note down the cut in Voltage of the diode.
REVERSE BIAS CHARACTERISTICS:

1. Connect the Circuit as per the Circuit Diagram on the bread board.

2. Switch on the Regulated Power Supply and slowly increase the source voltage.
Increase the Diode voltage in steps of 2.0 volts and note down the corresponding
1N4007
1N4007

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Current against the Voltage under Reverse Bias condition as per table given
below.
3. Take readings until a Diode Voltage reaches 30.0V.
4. Repeat the same by using Ge Diode instead of Si Diode.
5. Plot the graph VR versus IR on the graph Sheet in the 3
rd
quadrant as in Fig.

6. From the graph find out the Dynamic Reverse Bias resistance of the diode.
R =
V
R , r ac = VR .


I
R IR

7. Observe and note down the break down Voltage of the diode.

Forward Bias:

S.No Forward Voltage
VF(V)
Forward Current
IF(mA) 1. 0 0
2. 0.41 0.08
3. 0.5 0.19
4. 0.53 0.37
5. 0.56 0.84
6. 0.57 0.95
7. 0.58 1.29
8. 0.59 1.46
9. 0.60 1.76
10. 0.63 3.30
11. 0.65 4.80
12. 0.68 9.13

Reverse Bias
S.No Reverse Voltage Reverse Current
1. 0 0
2. 1 1
3. 2 2
4. 3 3
5. 5 5
6. 7 7
7. 8 8
8. 10 10
9. 12 12
10. 13 13
11. 14 14
12. 16 16

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MODEL GRAPH:



RESULT:

The V-I Characteristics of the PN Junction Diode are plotted for the both Forward
and Reverse Bias conditions and Calculated the Cut in Voltage, Dynamic Forward and
Reverse Bias resistance.

PRECAUTIONS:

1. Check the wires for continuity before use.
2. Keep the power supply at Zero volts before Start.
3. All the contacts must be intact.

VIVA QUESTIONS:

1. Draw the circuit symbol of the Diode?

2. What are the materials used for Anode and Cathode?
3. Draw ideal Diode Volt Ampere Characteristics?
4. What is Cut in Voltage?
5. What are Static and Dynamic Resistances?
6. Explain the working of a Diode as a switch
7. What is space charge?
8. What is Diffusion Capacitance?
9. What are Minority and Majority carriers in P type and in N type materials?
10. What are the specifications of a Diode?
11. What is PIV?
12. Why leakage current is more for Ge Diode?
13. What is work function?
14. What is the current equation of the Diode?

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2. ZENER DIODE CHARACTERISTICS &ZENERDIODE AS VOLTAGE
REGULATOR
AIM: i) To Obtain the Forward Bias and Reverse Bias characteristics of a Zener diode.

ii) Find out the Zener Break down Voltage from the Characteristics.
iii) To Obtain the Load Regulation Characteristics.

APPARATUS:

S.No Name Range / Value Quantity

1 DC Regulated Power Supply 0 – 30 volts 1
2 Diode ECZ 5.1 1
3 Resistor 1K Each 1
4 D.C Ammeters 0–200mA 1
5 D.C Volt meters 0–2V, 0–20V Each 1
6 Decade Resistance Box - 1
7 Bread Board and connecting wires - 1 Set

THEORY:-
A zener diode is heavily doped p-n junction diode, specially made to operation the
break down region. A p-n junction diode normally does not conduct when reverse biased. But
if the reverse bias is increased, at a particular voltage it starts conducting heavily. This voltage
is called Break down Voltage. High current through the diode can permanently damage the
device. To avoid high current, we connect a resistor in series with zener diode. Once the diode
starts conducting it maintains almost constant voltage across the terminals whatever may be the
current through it, i.e., it has very low dynamic resistance. It is used in voltage regulators.
CIRCUIT DIAGRAMS:-
FORWARD BIAS:-

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REVERSE BIAS:-


VOLTAGE REGULATION:














FORWARD BIAS CHARACTERISTICS :
1. Connect the Circuit as per the Circuit Diagram on the bread board.
2. Switch on the Regulated Power Supply and slowly increase the source voltage.
Increase the Diode Current in steps of 2mA and note down the corresponding
voltage across the Zener Diode under forward Bias condition as per table given
below.

3. Take the readings until a Diode Current of 20mA.
4. Plot the graph VF versus IF on the graph Sheet in the 1
st
quadrant as in Fig.

5. From the graph find out the Static & Dynamic forward Bias resistance of the
diode
R = VF , rac = VF .

IF IF


REVERSE BIAS CHARACTERISTICS:
1. Connect the Circuit as per the Circuit Diagram on the bread board.
2. Switch on the Regulated Power Supply and slowly increase the source voltage.
Increase the Diode Current in steps of 2mA and note down the corresponding
voltage across the Zener Diode under Reverse Bias condition as per table given
below.

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3. Take the readings until a Diode Current of 20mA.
4. Plot the graph VR versus IR on the graph Sheet in the 3
rd
quadrant as in Fig.

5. From the graph find out the Dynamic Reverse Bias resistance of the diode.
R =
V
R ,
IR

7. Observe and note down the break down Voltage of the diode.

LOAD REGULATION CHARACTERISTICS :

1. Connect the Circuit as per the Circuit Diagram on the bread board.
2. By changing the load Resistance, kept constant I/P Voltage at 5V, 10 V, 15 V
as per table given below. Take the readings of O/P Voltmeter (Vo=Vz).
3. Now by changing the I/P Voltage, kept constant load Resistance at 1K, 2K, 3K
as per table given below. Take the readings of O/P Voltmeter (Vo=Vz).

Forward Bias:



Reverse Bias:

S.No ReverseVoltage ReverseCurrent
1 0 0
2 0.5 0.5
3 1 1
4 1.5 1.5
5 2.0 2.0
6 2.5 3.3
7 3.0 10.0
8 3.5 32.0
9 4.0 138



S.No ForwardVoltage ForwardCurrent
1 0 0
2 0.6 0.03
3 0.65 0.31
4 0.7 1.2
5 0.71 2.0
6 0.72 2.73
7 0.73 3.95
8 0.74 4.87
9 0.75 6.53
10 0.76 10.53
11 0.77 13.12
12 0.78 17.8
13 0.79 18.1

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MODEL GRAPHS:

ZENER DIODE CHARACTERISTICS :
















LOAD REGULATION CHARACTERISTICS :-












ZENER BREAKDOWN VOLTAGE:

Draw a tangent on the reverse Bias Characteristic of the Zener Diode starting from
the Knee and touching most of the points of the curve. The point where the tangent
intersects the X-axis is the Zener Breakdown Voltage.

RESULT:

The Characteristics of the Forward and Reverse biased Zener Diode and the
Zener Break Down Voltage from the Characteristics are Observed.
Zener Breakdown Voltage = Volts.
Forward Bias Resistance = Ohms
Reverse Bias Resistance = Ohms

PRECAUTIONS:

1. Check the wires for continuity before use.
2. Keep the power supply at Zero volts before Start.
3. All the contacts must be intact.
VIVA QUESTIONS:

1. Draw the circuit symbol of the Zener Diode
2. What is meant by Zener break down?
3. What are the different types of break downs?
4. What is the difference between Avalanche Zener break down?

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5. In a lightly doped and heavily doped diode which type of break down occurs?
6. Why Zener break down and Avalanche BD voltage increase with temperature?
7. What are the applications of Zener diode?
8. Explain operation of Zener diode as Voltage Regulator?
9. What is the difference between normal PN Jn diode and Zener diode?
10 hat is a Regulation?

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3. FULL WAVE RECTIFIER WITH & WITHOUT FILTERS
AIM: To Rectify the AC signal and then to find out Ripple factor and percentage of
Regulation in Full-wave rectifier center tapped circuit with and without Capacitor
filter.

APPARATUS:

S.No Name Range / Value Quantity

1 Transformer 230V / 9-0-9V 1
2 Diode 1N4001 2
3 Capacitors 1000F/16V, 470f/25V 1
4 Decade Resistance Box - 1
5 Multimeter - 1
6 Bread Board and connecting wires - 1
7 Dual Trace CRO 20MHz 1

CIRCUIT DIAGRAMS:

WITHOUT FILTER AND WITH FILTER:

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THEORY:
A Rectifier is an electrical device that converts alternating current (AC), which
periodically reverses direction, to direct current (DC), which flows in only one
direction. The process is known as rectification. Physically, rectifiers take a number of
forms, including vacuum tube diodes, mercury-arc valves, copper and selenium oxide
rectifiers, semiconductor diodes, silicon-controlled rectifiers and other silicon-based
semiconductor switches. Historically, even synchronous electromechanical switches
and motors have been used. Early radio receivers, called crystal radios, used a "cat's
whisker" of fine wire pressing on a crystal of galena (lead sulfide) to serve as a point-
contact rectifier or "crystal detector".
Because of the alternating nature of the input AC sine wave, the process of rectification
alone produces a DC current that, though unidirectional, consists of pulses of current.
Many applications of rectifiers, such as power supplies for radio, television and
computer equipment, require a steady constant DC current (as would be produced by a
battery).
The circuit of a center-tapped full wave rectifier uses two diodes D1&D2.
During positive half cycle of secondary voltage (input voltage), the diode D1 is forward
biased and D2is reverse biased. The diode D1 conducts and current flows through load
resistor RL. During negative half cycle, diode D2 becomes forward biased and D1
reverse biased. Now, D2 conducts and current flows through the load resistor RL in the
same direction. There is a continuous current flow through the load resistor RL, during
both the half cycles and will get unidirectional current as show in the model graph. The
difference between full wave and half wave rectification is that a full wave rectifier
allows unidirectional (one way) current to the load during the entire 360 degrees of the
input signal and half-wave rectifier allows this only during one half cycle (180 degree).

PROCEDURE:

WITHOUT FILTER:

1. Connecting the circuit on bread board as per the circuit diagram.

2. Connect the primary of the transformer to main supply i.e. 230V, 50Hz
3. Connect the decade resistance box and set the RL value to 100Ω

4. Connect the Multimeter at output terminals and vary the load resistance (DRB)
from 100Ω to 1KΩ and note down the Vac and Vdc as per given tabular form
5. Disconnect load resistance ( DRB) and note down no load voltage Vdc (V no load)
6. Connect load resistance at 1KΩ and connect Channel – II of CRO at output
terminals and CH – I of CRO at Secondary Input terminals observe and note
down the Input and Output Wave form on Graph Sheet.
7. Calculate ripple factor  
V
ac

V
dc
8. Calculate Percentage of Regulation, % 
V
no load

V
full load
100%
V
no load


WITH CAPACITOR FILTER:

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1. Connecting the circuit as per the circuit Diagram and repeat the above procedure
from steps 2 to 8.
FWR with out capacitor
S.No R(KΩ) VdcFL

Vac Γ=Vac/Vdc
1 1 9.65 4.49 0.4652
2 2 9.58 4.47 0.4665
3 3 9.58 4.47 0.4665
4 4 9.59 4.48 0.4671
5 5 9.63 4.50 0.4672
6 6 9.63 4.49 0.4662
7 7 9.65 4.51 0.4663
8 8 9.64 4.51 0.4678
9 9 9.65 4.51 0.4673
10 10 9.64 4.51 0.4678

FWR with capacitor

S.No R(KΩ) VdcFL

Vac Γ=Vac/Vdc
1 1 15.26 0.01 0.000655
2 2 15.22 0.01 0.000634
3 3 15.26 0.01 0.000655
4 4 15.27 0.01 0.000655
5 5 15.26 0.01 0.0006557
6 6 15.25 0.01 0.000658
7 7 15.19 0.01 0.000659
8 8 15.17 0.01 0.0006587
9 9 15.17 0.01 0.000658
10 10 15.19 0.01 0.0006587

WAVE SHAPES:









MODEL GRAPHS:

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RESULT: Observe Input and Output Wave forms and Calculate ripple factor and
percentage of regulation in Full-wave rectifier with and without filter.

Without Filter:

Ripple Factor :
Regulation :

With Capacitor Filter:

Ripple Factor :
Regulation :



PRECAUTIONS:

1. Check the wires for continuity before use.

2. Keep the power supply at Zero volts before Start.
3. All the contacts must be intact.

VIVA QUESTIONS:

1. What is a full wave rectifier?

2. How Diode acts as a rectifier?
3. What is the significance of PIV requirement of Diode in full-wave rectifier?
4. Compare capacitor filter with an inductor filter?
5. Draw the o/p wave form without filter? Draw the O/P? What is wave form
with filter?
6. What is meant by ripple factor? For a good filter whether ripple factor should
be high or low? What happens to the ripple factor if we insert the filter?
7. What is meant by regulation? Why regulation is poor in the case of inductor filter?

8. What is meant by time constant?
9. What happens to the o/p wave form if we increase the capacitor value?
What happens if we increase the capacitor value?
10. What is the theoretical maximum value of ripple factor for a full wave rectifier?

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4. INPUT&OUTPUT CHARACTERISTICS OF BJT IN CE CONFIGURATION

AIM: To plot the Input and Output characteristics of a transistor connected in
Common Emitter Configuration

APPARATUS:

S.No Name Range / Value Quantity

1 Dual Regulated D.C Power supply 0–30 Volts 1
2 Transistor BC107 1
3 Resistors 120K 1
4 DC Ammeters (0-200A), (0-200mA) Each 1 No
5 DC Voltmeters (0-2V), (0-20V) Each 1 No
6 Bread Board and connecting wires - 1 Set

CIRCUIT DIAGRAM:-








THEORY:

A transistor is a three terminal device. The terminals are emitter, base, collector. In
common emitter configuration, input voltage is applied between base and emitter
terminals and out put is taken across the collector and emitter terminals. Therefore the
emitter terminal is common to both input and output. The input characteristics resemble
that of a forward biased diode curve. This is expected since the Base-Emitter junction
of the transistor is forward biased. As compared to CB arrangement IB increases less
rapidly with VBE . Therefore input resistance of CE circuit is higher than that of CB
circuit. The output characteristics are drawn between Ic and VCE at constant IB. the
collector current varies with VCE unto few volts only. After this the collector current
becomes almost constant, and independent of VCE. The value of VCE up to which the
collector current changes with VCE is known as Knee voltage. The transistor always
operated in the region above Knee voltage, IC is always constant and is approximately
equal to IB.

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The current amplification factor of CE configuration is given by

Β = ∆IC/∆IB.

The transistor always operates in the active region. I.e. the collector current IC increases
with VCE very slowly. For low values of the VCE the IC increases rapidly with a small
increase in VCE .The transistor is said to be working in saturation region.
Output resistance is the ratio of change of collector emitter voltage ∆VCE , to change
in collector current ∆IC with constant IB. Output resistance or Output Impedance

PROCEDURE:

TO FIND THE INPUT CHARACTERISTICS:

1. Connect the circuit as in the circuit diagram.

2. Keep VBB and VCC in zero volts before giving the supply
3. Set VCE = 1 volt by varying VCC and vary the VBB smoothly with fine
control such that base current IB varies in steps of 5μA from zero upto
200μA, and note down the corresponding voltage VBE for each step in the
tabular form.
4. Repeat the experiment for VCE =2 volts and 3 volts.
5. Draw a graph between VBE Vs IB against VCE = Constant.


TO FIND THE OUTPUT CHARACTERISTICS:

1. Start VEE and VCC from zero Volts.

2. Set the IB = 20μA by using VBB such that, VCE changes in steps of 0.2 volts
from zero upto 10 volts, note down the corresponding collector current IC
for each step in the tabular form.
3. Repeat the experiment for IE = 40μA and IE = 60μA, tabulate the readings.
4. Draw a graph between VCE Vs IC against IB = Constant.


TABULAR FORMS:

INPUT CHARACTERISTICS :

S.No VBE VCE=2V
IB
VCE=4V
IB
VCE=6V
IB
1 0 0 0 0
2 0.1 0 0 0
3 0.2 0.1 0 0
4 0.35 0.4 0.4 0.1
5 0.43 0.9 1 2
6 0.5 3.3 5.3 2.5
7 0.6 3.8 16 16.5
8 0.7 123 109 98

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OUTPUT CHARACTERISTICS:

S.No Vce IB=10uA
IE
IB=20uA
IE
IB=30uA
IE
1 0 0 0 0
2 0 0 0 0
3 1.5 1.8 4.1 6.4
4 2.1 1.8 4.1 6.4
5 3 1.8 4.1 6.4
6 4 1.8 4.1 6.4
7 5 1.8 4.1 6.4
8 6 1.8 4.1 6.4


INPUT CHARACTERISTICS: OUTPUT CHARACTERISTICS:








RESULTS:

The input and out put characteristics are drawn on the graphs

VIVA QUESTIONS:
1. What is the range of β for the transistor?
2. What are the input and output impedances of CE configuration?
3. Identify various regions in the output characteristics?
4. What is the relation between α and β
5. Define current gain in CE configuration?
6. Why CE configuration is preferred for amplification?
7. What is the phase relation between input and output?
8. Draw diagram of CE configuration for PNP transistor?
9. What is the power gain of CE configuration?

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5. Input and output characteristics of FET in CS Configuration
AIM:

To conduct an experiment on a given JFET and obtain
1) Drain characteristics
2) Transfer Characteristics.
3) To find rd, gm, and μ from the characteristics.

APPARATUS:

S.No Name Range / Value Quantity

1 Dual Regulated D.C Power supply (0–30 Volts) 1
2 JFET BFW 10 or 11 1
3 D.C Ammeter (0 – 20mA) 1
4 D.C Voltmeters (0 – 2V), (0 – 20V) Each 1
5 Bread Board and connecting wires -- 1 Set


CIRCUIT DIAGRAM:-










THEORY:
A FET is a three terminal device, having the characteristics of high input impedance and less
noise, the Gate to Source junction of the FET s always reverse biased. In response to small applied
voltage from drain to source, the n-type bar acts as sample resistor, and the drain current increases
linearly with VDS. With increase in ID the ohmic voltage drop between the source and the channel
region reverse biases the junction and the conducting position of the channel begins to remain constant.
The VDS at this instant is called “pinch of voltage”. If the gate to source voltage (VGS) is applied in
the direction to provide
additional reverse bias, the pinch off voltage ill is decreased. In amplifier application, the FET is
always used in the region beyond the pinch-off.

IDS=IDSS(1-VGS/VP)^2

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PROCEDURE:

DRAIN CHARACTERISTICS:

1. Connect the circuit as per the Fig. 1 and start with VGG and VDD keeping at zero volts.

2. Keep VGG such that VGS = 0 volts, Now vary VDD such that VDS Varies in steps of 1
volt up to 10 volts. And Note down the corresponding Drain current ID
3. Repeat the above experiment with VGS = -1V and -2V and tabulate the readings.
4. Draw a graph VDS Vs ID against VGS as parameter on graph.
5. From the above graph calculate rd and note down the corresponding diode current
against the voltage in the tabular form.
6. Draw the graph between voltages across the Diode Vs Current through the diode in the
first quadrant as shown in fig.

TRANSFER CHARACTERISTICS:

1. Set VGG and VDD at zero volts .keep VDS = 1Volt.

2. Vary VGG such that VGS varies in steps of 0.5 volts. Note down the corresponding
Drain current ID, until ID = 0mA and Tabulate the readings.
3. Repeat the above experiment for VDS = 3.0 Volts and 5.0 Volts and tabulate the
readings.
4. Draw graph between VGS Vs ID with VDS as parameter.
5. From the graph find gm.
6. Now μ = gm x rd.

TABULAR FORM:

TRANSFER CHARACTERISTICS:

S.No VGS(V)

VDS=2V
ID(mA)
VDS=6V
ID(mA)
1 -0.1 4.18 4.85
2 -0.2 4.04 4.62
3 -0.3 3.92 4.37
4 -0.4 3.71 4.03
5 -0.5 3.44 3.60
6 -0.6 3.19 331
7 -0.7 2.89 2.87
8 -0.8 2.32 2.54
9 -0.9 2.18 2.22
10 -1 1.85 1.87

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11 -1.1 1.55 1.55
12 -1.2 1.26 1.28
13 -1.3 1.98 0.93
14 -1.4 0.75 0.60
15 -1.5 0.52 0.54

DRAIN CHARACTERISTICS:


S.No VDS VGS=-1
ID(mA)
VGS=-0.5
ID(mA)
1 0 0.15 0.17
2 0.5 1.2 1.86
3 1 1.56 2.98
4 1.5 1.70 3.26
5 2 1.78 3.57
6 2.5 1.81 3.61
7 3 1.83 3.67
8 3.5 1.85 3.69
9 4 1.87 3.74
10 4.5 1.88 3.74
11 5 1.89 3.74
12 5.5 1.89 3.74
13 6 1.9 3.74
14 6.5 1.91 3.75
15 7 1.92 3.75
16 7.5 1.92 3.75
17 8 1.92 3.75
18 8.5 1.92 3.75

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MODEL GRAPH:






CALCULATIONS:

CALCULATION OF r d :

Construct a Triangle on one of the output characteristic for a particular VGS in the active
region and find ΔVDS and ΔI D
Now rd = ΔVDS/ ΔID (VGS = constant)

CALCULATION OF gm :

Construct a Triangle on one of the Transfer characteristics for a particular VDS find ΔVGS
and ΔID.
Now gm = ΔID/Δ VGS (VDS = constant).

CALCULATION OF μ : μ = gm x rd.

RESULT: 1.The drain and transfer characteristics of a given FET are drawn

2. The dynamic resistance (rd), amplification factor (μ) and Tran conductance (gm)
of the given FET are calculated.
PRECAUTIONS:

1. Check the wires for continuity before use.

2. Keep the power supply at zero volts before starting the experiment.
3. All the contacts must be intact.
4. For a good JFET ID will be ≥ 11.0 mA at VGS = 0.0 volts if not change the JFET.

VIVA QUESTIONS:

1. What are the advantages of JFET over BJT?

2. Why input resistance in FET amplifier is more than the BJT amplifier?
3. What is a uni-polar device?
4. What is pinch off voltage?
5. What are various FETs?
6. What is Enhancement mode and Depletion mode?
7. Draw the Equivalent circuit of JFET for low frequencies?
8. Write the mathematical equation for gm in terms of gmo?
9. Write equation of FET ID in terms of VGS and Vp?

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6. COMMON EMITTER AMPLIFIER CHARACTERISTICS
AIM: To Find the frequency response of a Common Emitter Transistor Amplifier and to find the Bandwidth
from the Response, Voltage gain, Input Resistance, output resistance.

APPARATUS:

S.No Name Range / Value Quantity

1 Regulated D.C Power supply 0–30 Volts 1
2 Transistor BC107 1
3 Resistors 1K 2
4 Resistors 100k,10K, 4.7K. Each 1
5 Capacitors 10f 3
6 Potentio Meter -- 1
7 Signal Generator ( 0 – 1MHz) 1
8 Dual Trace CRO 20MHz 1
9 Bread Board and connecting wires -- 1 Set

CIRCUIT DIAGRAM:-










THEORY:
The CE amplifier provides high gain &wide frequency response. The emitter lead is common to both input
& output circuits and is grounded. The emitter-base circuit is forward biased. The collector current is controlled by
the base current rather than emitter current. The input signal is applied to base terminal of the transistor and amplifier
output is taken across collector terminal. A very small change in base current produces a much larger change in
collector current. When +VE half-cycle is fed to the input circuit, it opposes the forward bias of the circuit which
causes the collector current to decrease, it decreases the voltage more –VE. Thus when input cycle varies through a -
VE half-cycle, increases the forward bias of the circuit, which causes the collector current to increases thus the output
signal is common emitter amplifier is in out of phase with the input signal.

PROCEDURE:

1. Connect the circuit as per the Fig.1.,Apply Vcc of 12 Volts DC.

2. Apply I/P Voltage of 20mV at 1KHz from the Signal Generator and observe the O/P on CRO.
3. Vary the frequency from 50 Hz to 1MHz in appropriate steps and note down the corresponding O/P
Voltage Vo in a tabular form .

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4. Calculate the Voltage Gain Av = Vo/Vs and note down in the tabular form.
5. Plot the frequency (f) Vs Gain (Av) on a Semi-log Graph sheet
6. Draw a horizontal line at 0.707 times Av and note down the cut off points and the Bandwidth is given
by B.W = f2 – f1.

INPUT RESISTANCE RI:

1. Apply I/P Voltage of 20mV at 1KHz from the Signal Generator and observe voltage Vi across R2 on
CRO.
2. Without Disturbing the setup note Vi.
3. find Ii = (Vs – Vi) / Rs and Ri= Vi / Ii Ohms.

OUTPUT RESISTANCE (R O):

1. Apply I/P Voltage of 50mV at 1KHz from the Signal Generator and observe the o/p on CRO
2. Connect a Potentio meter across the O/P terminals and without disturbing Vs adjust the potentiometer
such that o/p falls to V0/2

3. The Resistance of the potentiometer is equal to Ro.
TABULAR FORMS:


S.No Frequency (Hz)
O/P Voltage,
Vo (V)
Voltage Gain
Av =Vo/Vi Av in dB= 20 log (Av)
1 10 1.2 0.1 -2
2 100 2.2 0.83 -14.75
3 700 2.4 0.2 -13.97
4 1K 2.4 0.2 -13.97
5 10K 2.4 0.2 -13.97
6 100K 2 0.167 -15.54
7 500K 0.8 0.067 -23.47
8 1M 0.4 0.033 -30.45

MODEL GRAPH:






RESULT:

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BandWidth B.W = f2 – f1 = Hz
Voltage Gain Av =
Input Resistance Ri = ohms
Output Resistance Ro = ohms

PRECAUTIONS:

1. Check the wires for continuity before use.

2. Keep the power supply at Zero volts before Start
3. All the contacts must be intact

VIVA QUESTIONS:

1. What is an Amplifier?

2. How many types of an Amplifiers?
3. What is meant Band width, Lower cut-off and Upper cut-off frequency?

4. How much phase shift for CE Amplifier?
5. What are the applications?
6. Draw the Equivalent circuit for low frequencies?

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7. COMMON BASE AMPLIFIER CHARACTERISTICS

Aim : To study the CB amplifier characteristics.

Apparatus:


S.No Name Range / Value Quantity

1 Regulated D.C Power supply 0–30 Volts 1
2 Transistor BC107 1
3 Resistors 1K 2
4 Resistors 100k,10K, 4.7K. Each 1
5 Capacitors 10f 3
6 Potentio Meter -- 1
7 Signal Generator ( 0 – 1MHz) 1
8 Dual Trace CRO 20MHz 1
9 Bread Board and connecting wires -- 1 Set

Circuit Diagram:




















Theory:
The common base amplifier is the least widely used of the three transistor amplifier configurations. The common emitter
and common collector (emitter follower) configurations are far more widely used because their characteristics are generally
more useful.
The common base amplifier configuration comes into its own at high frequencies where stability can be an issue.
For both NPN and PNP circuits, it can be seen that for the common base amplifier circuit, the input is applied to the emitter,
and the output is taken from the collector. The common terminal for both circuits is the base. The base is grounded for the
signal and for this reason the circuit may sometimes be called a grounded base circuit.
The common base amplifier configuration is not used as widely as transistor amplifier configurations. However it does find
uses with amplifiers that require low input impedance levels. One application is for moving-coil microphones
preamplifiers - these microphones have very low impedance levels.
Another application is within VHF and UHF RF amplifiers where the low input impedance allows accurate
matching to the feeder impedance which is typically 50Ω or 75Ω. The configuration also improves stability
which is a key issue.
It is worth noting that the current gain of a common-base amplifier is always less than unity.

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However the voltage gain is more, but it is a function of input and output resistances (and also the internal
resistance of the emitter-base junction). As a result, the voltage gain of a common-base amplifier can be
very high.
PROCEDURE:

1. Connect the circuit as per the Fig.1.,Apply Vcc of 12 Volts DC.

2. Apply I/P Voltage of 20mV at 1KHz from the Signal Generator and observe the O/P on CRO.
3. Vary the frequency from 50 Hz to 1MHz in appropriate steps and note down the corresponding O/P
Voltage Vo in a tabular form .
4. Calculate the Voltage Gain Av = Vo/Vs and note down in the tabular form.
5. Plot the frequency (f) Vs Gain (Av) on a Semi-log Graph sheet
6. Draw a horizontal line at 0.707 times Av and note down the cut off points and the Bandwidth is given
by B.W = f2 – f1.


TABULAR FORMS:

I/P Voltage, Vs = 20Mv

S.No Frequency (Hz) O/P Voltage, Vo (V)
Voltage Gain Av in dB

Av =Vo/Vi

= 20 log (Av)






1 100

2 200

3 300

4 500

5 700

6 1K

7 3K

8 5K

9 7K

10 10K



Model Graph:












RESULT:
BandWidth B.W = f2 – f1 = Hz
Voltage Gain Av =
Input Resistance Ri = ohms
Output Resistance Ro = ohms

PRECAUTIONS:

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4. Check the wires for continuity before use.

5. Keep the power supply at Zero volts before Start
6. All the contacts must be intact

VIVA QUESTIONS:

7. What is an Amplifier?

8. How many types of an Amplifiers?
9. What is meant Band width, Lower cut-off and Upper cut-off frequency?

10. How much phase shift for CB Amplifier?
11. What are the applications?
12. Draw the Equivalent circuit for low frequencies?

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8. COMMON SOURCE AMPLIFIER CHARACTERISTICS

AIM:


1.To obtain Frequency response characteristics of Common Source FET amplifier

2.To determine Bandwidth.

Apparatus

S.No Apparatus Range Quantity



01 N-Channel FET
BFW10
01

02 Resistance (6.8KΩ, 1MΩ, 1.5KΩ) 01

03 Regulated Power supply (0-30V) 01

04 Capacitor (0.1µF, 0.1µF, 47µF) 01

05 Signal Generator 10-1M Hz 01

06 CRO 01

07 Breadboard and Wires ,CRO

08 Probes

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Circuit Diagram
















Procedure:

1. Connections are made as per the circuit diagram.
2. A 10V supply is given to the circuit.
3. A certain amplitude of input signal (say 20mv at 1 kHz) is kept constant using signal
generator and for different frequencies, the output voltage (V0) is taken at Drain from
CRO .
4. Gain of the amplifier is calculated using Gain(dB)
5.Plot the graph between Gain in dB and frequency.

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TABULAR FORMS:
I/P Voltage, Vs = 20mV

S.No Frequency (Hz) O/P Voltage, Vo (V)
Voltage Gain Av in dB

Av =Vo/Vi

= 20 log (Av)






1 100

2 200

3 300

4 500

5 700

6 1K

7 3K

8 5K

9 7K

10 10K


Model Graph

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Calculations from Graph

1.Draw a line at maximum gain(dB) less than by 3dB parallel to the X-axis as shown
in the figure
















2.Draw two lines at the intersection of the characteristic curve and the 3dB line
onto the X-axis which gives the (fH) and (fL)

3.The difference between fH and fL gives the Bandwidth of the amplifier.

Precautions:
1. While doing the experiment do not exceed the ratings of the transistor. This may
lead to damage of the transistor.

2. Do not switch ON the power supply unless you have checked the circuit
connections as per the circuit diagram.

3. Transistor terminals must be identified properly.

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Result

Frequency response of CS FET amplifier was plotted and Bandwidth was
determined and it is given as BW=

VIVA QUESTIONS:

1.What is an amplifier?

2.Explian the effect of capacitors on frequency response?

3.why gain is constant in mid frequency region?

4.what is bandwidth?

5.what is the relation between bandwidth and gain?

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9. MEASUREMENT OF H -PARAMETERS OF TRANSISTOR IN
CB, CE, CC CONFIGURATIONS


Aim: To measure the H-parameters of transistor in CE,CB,CC configurations.

Theory:
Hybrid Parameters or h Parameters
Hybrid parameters (also known as h parameters) are known as ‘hybrid’ parameters as they
use Z parameters, Y parameters, voltage ratio, and current ratios to represent the relationship
between voltage and current in a two port network.
H parameters are useful in describing the input-output characteristics of circuits where it is hard
to measure Z or Y parameters (such as a transistor). H parameters encapsulate all the important
linear characteristics of the circuit, so they are very useful for simulation purposes. The
relationship between voltages and current in h parameters can be represented as:

This can be represented in matrix form as:

To illustrate where h parameters are useful, take the case of an ideal transformer, where Z
parameters cannot be used. Since here, the relations between voltages and current in that ideal
transformer would be,

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Since, in an ideal transformer voltagescan not be expressed in terms of current, it is impossible
to analyze a transformer with Z parameters because a transformer does not have Z parameters.
The problem can be solved by using hybrid parameters (i.e. h parameters).
Determining h Parameters
Let us short circuit the output port of a two port network as shown below,

Now, ratio of input voltage to input current, at short circuited output port is:

This is referred to as the short circuit input impedance. Now, the ratio of the output current to
input current at the short-circuited output port is:

This is called short-circuit current gain of the network. Now, let us open circuit the port 1. At
that condition, there will be no input current (I1=0) but open circuit voltage V1 appears across
the port 1, as shown below:

Now:

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This is referred as reverse voltage gain because, this is the ratio of input voltage to the output
voltage of the network, but voltage gain is defined as the ratio of output voltage to the input
voltage of a network.
Now:

It is referred as open circuit output admittance.
h Parameter Equivalent Network of Two Port Network
To draw h parameter equivalent network of a two port network, first we have to write the
equation of voltages and currents using h parameters. These are:

Equation (i) can be represented as a circuit based on Kirchhoff Voltage Law:

Equation (ii) can be represented as a circuit based on Kirchhoff Current Law:

Combining these two parts of the network we get:

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H-parameter model of CE configuration

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Expected waveforms:

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Results: H-parameters for all the CE,CC,CB configurations are calculated.
Precautions
1. Check the wires for continuity before use.

2. Keep the power supply at zero volts before starting the experiment.
3. All the contacts must be intact.

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10. SWITCHING CHARACTERISTICS OF A TRANSISTOR
Aim:
Design Transistor to act as a Switch and verify the operation. Choose VCC = 10V, ICmax =
10 mA, hfe = 50, VCESat = 0.2, Vin = 4Vp-p, VBESat = 0.6 V
Apparatus:
1. Transistor (BC 107).
2. Breadboard.
3. CRO.
4. Resistors (1K, 8.2K).
5. RPS.
6. Function Generator.
7. Connecting patch cards.
Theory:
When the I/P voltage Vi is negative or zero, transistor is cut-off and no current flows
through Rc hence V0  VCC when I/P Voltage Vi jumps to positive voltage, transistor will be driven
into saturation. Then
V0 = Vcc – ICRC  VCESat
Design procedure:




Circuit diagram:

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Procedure:
1. Connect the circuit as shown in figure.
2. Apply the Square wave 4 Vp-p frequency of 1 KHz
3. Observe the waveforms at Collector and Base and plot it.
Precautions:
1. When you are measuring O/P waveform at collector and base, keep the CRO in DC
mode.
2. When you are measuring VBE Sat, VCE Sat keep volts/div switch at either 0.2 or 0.5
position.
3. When you are applying the square wave see that there is no DC voltage in that. This
can be checked by CRO in either AC or DC mode, there should not be any
jumps/distortion in waveform on the screen.
Expected waveforms:

Result:
Transistor as a switch has been designed and O/P waveforms are observed.

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Viva Questions:

1. Differentiate between Diode and Transistor as a switch?
2. Mention typical values of VBE Sat, VCE Sat for both Si, Ge Transistors?
3. Define ON time, OFF time of the transistor?
4. In which regions Transistor acts as a switch?
5. Explain phenomenon of “ latching “ in a Transistor switch?
6. Define Rise time & fall time of a transistor switch?

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11. SCR CHARACTERISTICS

AIM: To draw the V-I Characteristics of SCR.
APPARATUS: SCR (TYN616)
Regulated Power Supply (0-30V)
Resistors 10KOhm, 1KOhm
Ammeter (0-50) μA
Voltmeter (0-10V)
Bread board and connecting wires.

CIRCUIT DIAGRAM:-




THEORY:
It is a four layer semiconductor device being alternate of P-type and N-type silicon. It
consists os 3 junctions J1, J2, J3 the J1 and J3 operate in forward direction and J2operates in
reverse direction and three terminals called anode A, cathode K , and a gate G. The operation of
SCR can be studied when the gate is open and when the gate is positive with respect to cathode.
When gate is open, no voltage is applied at the gate due to reverse bias of the junction J2
no current flows through R2 and hence SCR is at cutt off. When anode voltage is increased J2
tends to breakdown. When the gate positive,with respect to cathode J3 junction is forward biased
and J2 is reverse biased .Electrons from N-type material move across junction J3towards gate
while holes from P-type material moves across junction J3 towards cathode. So gate current starts
flowing ,anode current increaase is in extremely small current junction J2 break down and SCR
conducts heavily. When gate is open thee breakover voltage is determined on the minimum
forward voltage at which SCR conducts heavily.Now most of the supply voltage appears across
the load resistance.The holfing current is the maximum anode current gate being open , when
break over occurs.
PROCEDURE:
1. Connections are made as per circuit diagram.

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2. Keep the gate supply voltage at some constant value
3. Vary the anode to cathode supply voltage and note down the readings of voltmeter
and ammeter. Keep the gate voltage at standard value.
4. A graph is drawn between VAK and IAK.

OBSERVATIONS:-

VAK IAK


MODEL WAVEFORM: -



RESULT: - The V-I Characteristics of SCR is verified.
VIVA QUESTIONS
1. What the symbol of SCR?
2. IN which state SCR turns of conducting state to blocking state?
3. What are the applications of SCR?
4. What is holding current?
5. What are the important type’s thyristors?
6. How many numbers of junctions are involved in SCR?
7. What is the function of gate in SCR?
8. When gate is open, what happens when anode voltage is increased?
9. What is the value of forward resistance offered by SCR?

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EXPERINEMT No.12
TYPES OF CLIPPERS AT DIFFERENT REFERENCE VOLTAGES

Aim:
a) To study the clipping circuits using diodes.
b) To observe the transfer characteristics of all the clipping circuits in CRO.
Apparatus:
1. Function Generator.
2. Bread board
3. Connecting patch cards.
4. CRO
5. RPS
6. Resistors (1 K, 10K)
7. Diodes (1N4007)

Theory:
Clipping circuits basically limit the amplitude of the input signal either below or above certain
voltage level. They are referred to as Voltage limiters, Amplitude selectors or Slicers. A clipping circuit
is one, in which a small section of input waveform is missing or cut or truncated at the out put section.
Clipping circuits are classified based on the position of Diode.
1.Series Diode Clipper
2.Shunt Diode Clipper
Procedure:
1. Connect the circuit as shown in fig.1
2. In each case apply 10 VP-P, 1KHz Sine wave I/P using a signal generator.
3. O/P is taken across the load RL.
4. Observe the O/P waveform on the CRO and compare with I/P waveform.
5. Sketch the I/P as well as O/P waveforms and mark the numerical values.
6. Note the changes in the O/P due to variations in the reference voltage VR = 2V, 3V..
7. Obtain the transfer characteristics of Fig.1, by keeping CRO in X-Y mode.
8. Repeat the above steps for all the circuit.

Precautions:
1. Set the CRO O/P channel in DC mode always.
2. Observe the waveform simultaneously by keeping common ground.
3. See that there is no DC component in the I/P.

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4. To find transfer characteristics apply input to the X-Channel, O/P to Y-Channel, adjust the dot at the
center of the screen when CRO is in X-Y mode. Both the channels must be in ground, then remove
ground and plot the transfer characteristics.

Circuit Diagram Input&Output Wave Forms

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Circuit Diagram O/P Wave Forms

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Result: Different types of clipping circuits have been studied and observed the responses for various
combinations of VR and clipping diodes.


Questions:
1. Define clipping circuit?
2. What are the different types of clippers?
3. What is a break region?
4. Which kind of a clipper is called a slicer circuit?
5. What are the disadvantages of the shunt clipper?
6. What are the disadvantages of the series clipper?
7. What is piecewise linear mode of a diode?

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EXPERINEMT No.13
TYPES OF CLIPPERS AT DIFFERENT REFERENCE VOLTAGES

Aim:
To study the clamping circuits using diodes and capacitors.

Apparatus:

1. Function Generator.
2. Bread board
3. Connecting patch cards.
4. CRO
5. RPS
6. Resistors ( 100 K )
7. Diodes (1N4007)
8. Capacitor (0.1f)

Theory:

Clamping circuits add a DC level to an AC signal. A clamper is also refer to as
DC restorer or DC re-inserter. The Clampers which clamp the given waveform either above or below the
reference level, which are known as positive or negative clamping respectively.

Procedure:
1. Connect the circuit as shown in fig.1.
2. Apply a Sine wave of 10VP-P, 1 KHz at the input terminals with the help of Signal Generator.
3. Observe the I/P & O/P waveforms of CRO and plot the waveforms and mark the values with VR = 2 V,
3V

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4. O/P is taken across the load RL.
5. Repeat the above steps for all clamping circuits as shown.
6. Waveforms are drawn assuming diode is ideal.





Circuit diagram I/P & O/P Wave Forms
















V0
-0.5V
9.5V
5V C1
0.1uF R1
100kohm
V1
10V
7.07V_rms
1000Hz
0Deg
D1
1N4007GP C1
0.1uF R1
100kohm
V1
10V
7.07V_rms
1000Hz
0Deg
D1
1N4007GP C1
0.1uF
R1
100kohm
V1
10V
7.07V_rms
1000Hz
0Deg
D1
1N4007GP
V2
2V

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Result:
Different types of clamping circuits are studied and observed the response for different combinations of
VR and diodes.

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Questions:

1.What are the applications of clamping circuits?
2.What is the synchronized clamping?
3.Why is a clamper called a dc inserter?
4.What is clamping circuit theorem. How dose the modified clamping
Circuit theorem differs from this?
5. Differentiate –ve clamping circuit from +ve clamping circuits in the
above circuits?
6. Describe the charging and discharging of a capacitor is each circuit?
7. What is the function of capacitor?
8. What are the effects of diode characteristics on the output of the
Clamper?

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EXPERINEMT No.14


The steady state output waveform of clampers for a square wave input

Aim:
To study the clamping circuits using diodes and capacitors.

Apparatus:

9. Function Generator.
10. Bread board
11. Connecting patch cards.
12. CRO
13. RPS
14. Resistors ( 100 K )
15. Diodes (1N4007)
16. Capacitor (0.1f)

Theory:

Clamping circuits add a DC level to an AC signal. A clamper is also refer to as
DC restorer or DC re-inserter. The Clampers which clamp the given waveform either above or below the
reference level, which are known as positive or negative clamping respectively.

Procedure:
7. Connect the circuit as shown in fig.1.
8. Apply a Square wave of 10VP-P, 1 KHz at the input terminals with the help of Signal Generator.
9. Observe the I/P & O/P waveforms of CRO and plot the waveforms and mark the values with VR = 2 V,
3V
10. O/P is taken across the load RL.
11. Repeat the above steps for all clamping circuits as shown.
12. Waveforms are drawn assuming diode is ideal.

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Circuit Diagrams and Wave forms

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Result:
Different types of clamping circuits are studied and observed the response for different combinations of
VR and diodes.
Questions:

1.What are the applications of clamping circuits?
2.What is the synchronized clamping?
3.Why is a clamper called a dc inserter?
4.What is clamping circuit theorem. How dose the modified clamping
Circuit theorem differs from this?
5. Differentiate –ve clamping circuit from +ve clamping circuits in the
above circuits?
6. Describe the charging and discharging of a capacitor is each circuit?
7. What is the function of capacitor?
8. What are the effects of diode characteristics on the output of the
Clamper?

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LEAD EXPERIMENT

EXPERIMENT:1 LED and Detector
In this lab, you are to perform some measurement to get familiar with the electrical and
opticalproperties ofthree typical LEDs
1. ThresholdvoltageonV‐Icurve
Using the setup as shown in Figure 1., where the current is provided by the voltage source V is
limited bythe series resistance R. Under operating conditions, the voltage drop across the LED is
Vd , the operatingvoltageofthedevice.Ifoperatingcurrentis I=Id, thenthecircuitcanbedescribedby


V— V
threshold= I
dR








Figure1
CircuitSetupforVIcurve
UseR=1kohm

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Figure2.VI curve you should be able to obtained Table1:Threshold voltage for
different didoes




Question:Does the LED light output increase linearly with current?What difference s are
there between the three different devices?

2. Frequencyresponse
Please use the function generator
and spectrumanalyzer. Sweep
frequency from 1 to 10M
Diode V
LED

Diode V
LED
infra-
red
1.2

blue 3.6
red 2.2

purple 3.6
yellow 2.2

ultra-
violet
3.7
green 3.5

white 3.6

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anddothepeakholdfunction to
generate
afrequencyresponseasshowninFigure3.







Figure3.Typicalelectricalfrequencyresponseofdiffe
rentLED