15EE209L- ANALOG AND DIGITAL CIRCUITS LAB RECORD …

15EE209L-ANALOG AND DIGITAL CIRCUITS LAB

1

15EE209L- ANALOG AND DIGITAL CIRCUITS LAB

RECORD

ACADEMIC YEAR: 20---20—

NAME :

REG.NO. :

DEPARTMENT OF ELECTRICAL & ELECTRONICS

ENGINEERING

FACULTY OF ENGINEERING & TECHNOLOGY

SRM INSTITUE OF SCIENCE AND TECHNOLOGY

(Under section 3 of UGC Act, 1956)

S.R.M. NAGAR, KATTANKULATHUR – 603 203

KANCHEEPURAM DISTRICT


2

SRM INSTITUTE OF SCIENCE AND TECHNOLOGY

(under Section 3 of UGC Act, 1956)

S.R.M. NAGAR, KATTANKULATHUR -603 203

KANCHEEPURAM DISTRICT

BONAFIDE CERTIFICATE

Register

No__________________

Certified to be the bonafide record of work done by

________________________ of EEE , B.Tech Degree course in the

Practical 15EE209L – ANALOG AND DIGITAL CIRCUITS LAB, in

SRM INSTITUTE OF SCIENCE AND TECHNOLOGY,

Kattankulathur during the academic year 20__-20__ .

Lab Incharge

Date: Year Co-ordinator HOD

Submitted for University Examination held in

Lab, SRM UNIVERSITY, Kattankulathur.

Date: Examiner-1 Examiner-2


3

INDEX

Sl.NO D.O.E Title of Experiment D.O.S Marks

1 Characteristics of BJT and FET

2 PSpice simulation of BJT and FET

characteristics

3 Half wave Rectifier & Full Wave rectifier

4 Clippers & clampers

5 Design of RC Phase Shift Oscillator

6 Frequency response of voltage series

feedback amplifier

7 Adders and Subtractors and Flip-Flops

8 Design of Multiplexer and Demultiplexer

9 Design of Counters

10 Design of Digital logic circuits using VHDL


4

DEPT. OF ELECTRICAL & ELECTRONICS ENGINEERING

SRM UNIVERSITY, Kattankulathur – 603203.

Experiment No. : 1

Title of Experiment : Characteristics of BJT and FET

Name of the candidate :

Register Number :

Date of Experiment :

Date of submission :

S.No: Marks split up Maximum Marks

(40)

Marks Obtained

1 Pre viva questions 5

2 Conduction 15

3 Calculation, Results and graph 15

4 Post viva questions 5

5 Total 40

Staff Signature


5

1. Characteristics of BJT and FET

Pre Lab Questions

1. When does a transistor act as an amplifier?

2. What are the types of configuration in a transistor?

3. Why h-parameters are called as hybrid parameters?

4. What is mutual conductance?

5. Define current gain and voltage gain

6. Why FET is called a Unipolar device?


6

Ex. No. 1

1.a. CHARACTERISTICS OF BJT

Aim

To plot the transistor characteristics of CE configuration.

Apparatus Required Components Required

S.No. Name Range Qty


1 R.P.S (0-30)V 2 1 Transistor BC 107 1

2 Ammeter

(0–30) mA

MC 1

2

Resistor 10 K 1

(0–250) µA

MC 1 Resistor 1 K 1

3 Voltmeter

(0–30)V

MC 1 3

Bread

Board 1

(0–1)V

MC 1 4 Wires

Theory

A BJT is a three terminal two – junction semiconductor device in which the

conduction is due to both the charge carrier. Hence it is a bipolar device. BJT is

classified into two types – NPN & PNP. A NPN transistor consists of two N types in

between which a layer of P is sandwiched. The transistor consists of three terminal

emitter, collector and base. The emitter layer is the source of the charge carriers and it is

heavily doped with a moderate cross sectional area. The collector collects the charge

carries and hence moderate doping and large cross sectional area. The base region acts a

path for the movement of the charge carriers. In order to reduce the recombination of

holes and electrons the base region is lightly doped and is of hollow cross sectional area.

Normally the transistor operates with the EB junction forward biased.


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Bottom View BC107

Specification: BC107/50V/0.1A,0.3W,300MH

Procedure

Input Characteristics

1. Connect the circuit as per the circuit diagram.

2. Set VCE, vary VBE in regular interval of steps and note down the corresponding IB

reading. Repeat the above procedure for different values of VCE.

3. Plot the graph: VBE vs IB for a constant VCE.

Output Characteristics


2. Set IB, Vary VCE in regular interval of steps and note down the corresponding IC

reading. Repeat the above procedure for different values of IB.

3. Plot the graph: VCE vs IC for a constant IB.

Pin Diagram B

E C C

Circuit Diagram


8

Model Graph

Input Characteristics Output Characteristics

Formula used

Tabular Column

Input Characteristics

VCE = 0 V VCE = 2V

VBE(V) IB(μA) VBE(V) IB(μA)

VCE = 0V

VCE = 5V

IB

µA mA

VBE(V) VCE(V)

0 0

IB=60A

IB=40A

IB=20A

IC


9

Output Characteristics

IB=20A IB=40A


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1.b Characteristics of FET

Aim:

To study Drain Characteristics and Transfer Characteristics of a Field Effect Transistor (FET).

Components:

S.No. Name Quantity

1 JFET (BFW11/ BFW10) 1(One) No.

2 Resistor (1K ,100K ) 1(One) No. Each

3 Bread board 1(One) No.

4 Dual DC Regulated Power supply (0 - 30 V) 1(One) No.

5 Digital Ammeters ( 0 - 200 mA) 1(One) No.

6 Digital Voltmeter (0 - 20V) 2(Two) No.

7 Connecting wires (Single Strand)

Specifications:

For FET BFW11:

Gate Source Voltage VGS = -30V

Forward Gain Current IGF = 10mA

Maximum Power Dissipation PD = 300mW

Circuit Diagram:


11

Top View Bottom View

Operation:

The circuit diagram for studying drain and transfer characteristics is shown in the circuit diagram.

1. Drain characteristics are obtained between the drain to source voltage (VDS) and drain

current (ID) taking gate to source voltage (VGS) as the constant parameter.

2. Transfer characteristics are obtained between the gate to source voltage (VGS) and drain

current (ID) taking drain to source voltage (VDS) as the constant parameter.

Procedure:

Drain Characteristics:

1. Connect the circuit as shown in the circuit diagram..

2. Keep VGS = 0V by varying VGG.

3. Varying VDD gradually in steps of 1V up to 10V note down drain current ID and drain to

source voltage (VDS).

4. Repeat above procedure for VGS = -1V.

Transfer Characteristics:

1. Connect the circuit as shown in the circuit diagram.

2. Set voltage VDS = 2V/5V (BFW10/ BFW11).

3. Varying VDD in steps of 0.5V until the current ID reduces to minimum value.

4. Varying VGG gradually, note down both drain current ID and gate-source voltage(VGS).

5. Repeat above procedure (step 3) for VDS = 4V/ 8V (BFW10/ BFW11).

Observations:


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Drain Characteristics

VDD (Volts) VGS = 0V VGS = -1V

VDS(Volts) ID(mA) VDS(Volts) ID(mA)

Transfer Characteristics

VGG (Volts) VDS = 2V/5V VDS = 4V/8V

VGS(Volts) ID(mA) VGS(Volts) ID(mA)

Graph:

1. Plot the drain characteristics by taking VDS on X-axis and ID on Y-axis at a constant VGS.

2. Plot the transfer characteristics by taking VGS on X-axis and taking ID on Y-axis at

constant VDS.

Calculations from Graph:


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1. Drain Resistance (rd): It is given by the relation of small change in drain to source

voltage( VDS) to the corresponding change in Drain Current( ID) for a constant gate to

source voltage ( VGS), when the JFET is operating in pinch-off region.

at a constant VGS (from drain characteristics)

2. Trans Conductance (gm): Ratio of small change in drain current( ID) to the

corresponding change in gate to source voltage ( VGS) for a constant VDS.

gm at constant VDS (from transfer characteristics).

The value of gm is expressed in mho’s ( ) or Siemens (s).

3. Amplification factor (µ): It is given by the ratio of small change in drain to source voltage

( VDS) to the corresponding change in gate to source voltage ( VGS) for a constant drain

current (ID).

Inference:

1. As the gate to source voltage (VGS) is increased above zero, pinch off voltage is increased

at a smaller value of drain current as compared to that when VGS = 0V.

2. The value of drain to source voltage (VDS) is decreased as compared to that when VGS =

0V.

Precautions:

1. While performing the experiment do not exceed the ratings of the FET. This may lead to

damage of FET.

2. Connect voltmeter and ammeter with correct polarities as shown in the circuit diagram.

3. Do not switch ON the power supply unless the circuit connections are checked as per the

circuit diagram.

4. Properly identify the Source, Drain and Gate terminals of the transistor.

Result:

Thus the input, output characteristics of BJT and Drain, transfer characteristics of a FET are

studied.


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Post Lab Questions

1 What is Punch through voltage?

2 What is early effect?

1. What is transconductance?

4. What is leakage current and mention its range?

5. What is base – width modulation?


15



Experiment No. : 2

Title of Experiment : PSpice simulation of BJT and FET characteristics


Register Number :




(40)

Marks Obtained


2 Conduction 15



5 Total 40

Staff Signature


16

2.Pspice simulation of BJT and FET

Aim: Simulate and study the V-I characteristics of BJT and FET

Circuit Diagram

Output Waveform

Procedure:

1.Start Capture CIS and create a new project called transistor curves.

2.The values entered for the sources IB and VCC on the schematic do not matter as both

are modified by PSpice during the DC Sweep Analysis.

3. Draw the circuit on the window.

4.At the Collector of Q1, place a Net Alias called IC.


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5.At the top of the current source, Place a Net Alias called IB.

6. Create a New Simulation Profile called Transistor Curves for DC Sweep. Enter the

values for the Primary Sweep using the values in the following graphic.


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FET:


19

OUTPUT WAVEFORM:


20

Result

Thus the simulation of BJT and FET characteristics were done using Pspice software.


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3.Halfwave and Full Wave Rectifier

Pre Lab Questions

1 What is the necessity of rectifier?

2 What is PIV of a diode in FWR and HWR?

3 What is ripple factor? Why it is required?

4 Why are filters connected at the output of rectifiers?

5 What are the types of filters used in rectifier? And which is better and why?

Types of filters


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Ex.No.3

SINGLE PHASE HALF WAVE RECTIFIER

Aim

To construct a Half wave rectifier using diode and to draw its performance characteristics.


S.

No. Name Range Qty

S.

No. Name Range Qty

1 Transformer 230/(6-0-6)V 1 1

Diode IN4007 1

2

R.P.S

(0-30)V

2

2 Resistor 1K 1

3 Bread

Board - 1

4 Capacitor 100µf 1

5 CRO - 1

Formulae

With out Filter

(i) Vrms = Vm / 2

(ii) Vdc = Vm /

(iii) Ripple Factor = ((Vrms / Vdc)2 – 1)

(iv) Efficiency = (Vdc / Vrms)2 x 100

With Filter

(i) V’rms = (Vrms2 + Vdc

2)

(ii) Vrms = Vrpp / (3 x 2)

(iii) Vdc = Vm – V rpp / 2

(iv) Ripple Factor = Vrms / Vdc


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Procedure

Without Filter

1. Give the connections as per the circuit diagram.

2. Give 230v, 50HZ I/P to the step down TFR where secondary connected to the

Rectifier I/P.

3. Take the rectifier output across the Load.

4. Plot its performance graph.

With Filter



Rectifier I/P.

3. Connect the Capacitor across the Load.



Circuit Diagram


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Tabular Column

Without Filter

Vm (V) Vrms (V) Vdc (V) Ripple factor Efficiency

With Filter

Vrpp (V) Vrms (V) Vdc (V) Ripple factor

Model Graph

Vin

(Volts)

t (ms)

Vo

(Volts)

t (ms)

t (ms)

Vo

(Volts)

Without Filter

With Filter


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SINGLE PHASE FULL WAVE RECTIFIER

Aim

To construct a Full wave rectifier using diode and to draw its performance

characteristics.


S.

No. Name Range Qty

S.

No. Name Range Qty

1 Transformer 230/(6-0-6)V 1 1

Diode IN4007 2

2

R.P.S

(0-30)V

2

2 Resistor 1K 1

3 Bread

Board - 1

4 Capacitor 100µf 1

5 CRO 1Hz-

20MHz 1

6 Connecting

wires - Req

Formulae

Without Filter

(i) Vrms = Vm / 2

(ii) Vdc = 2Vm /

(iii) Ripple Factor = ((Vrms / Vdc)2 – 1)

(iv) Efficiency = (Vdc / Vrms)2 x 100

With Filter

(i) Vrms = Vrpp /(2* 3)

(ii) Vdc = Vm – V rpp

(iv) Ripple Factor = Vrms’/ Vdc

Procedure

Without Filter



Rectifier I/P.



26


With Filter



Rectifier I/P.

3. Connect the Capacitor across the Load.



Circuit Diagram

Tabular Column

Without Filter

Vm Vrms Vdc Ripple factor Efficiency

With Filter

Vrms Vrpp Vdc Ripple factor


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Model Graph

Result

Thus the performance characteristics of 1 Half wave and Full wave rectifier were

obtained.

Vin

(Volts)

t (ms)

Vo

(Volts)

t (ms)

t (ms)

Vo

(Volts)

Without Filter

With Filter


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Post Lab Questions

1. What is TUF?

2. Mention the value of ripple factor for HWR, FWR & rectifier with centre tapped

transformer.

3. What is the difference between uncontrolled rectifier and controlled rectifier?

Which is advantageous and why?

4. State the average and peak value of output voltage and current for full wave

rectifier and half wave rectifier.

5. What is PIV of a diode in half wave and full wave rectifier?


29



Experiment No. :

Title of Experiment :


Register Number :




(30)

Marks Obtained


2 Conduction 15



5 Total 40

Staff Signature


30

4.Clippers and Clampers

Pre Lab Questions

1. What are the differences between linear and nonlinear wave shaping circuit?

2. What are the applications of wave shaping circuit?

3. What is wave shaping?

4. What is the necessity of wave shaping?

5. Mention the application of clipper and clamper.


31

Ex. No. 4 CLIPPERS AND CLAMPERS

Ex. No. 4a

CLIPPERS

Aim

To study the clipping circuits for different reference voltages and to verify the responses.




1 CRO 1Hz-20MHz 1

1 Resistor 10KΩ 1 2 RPS (0–30) V 1

3 Bread

Board - 1

4 Connecting

Wires - Req

2 Diode IN4007 1

5 Function

Generator 1Hz-1MHz 1

Theory

The non-linear semiconductor diode in combination with resistor can function as

clipper circuit. Energy storage circuit components are not required in the basic process of

clipping. These circuits will select part of an arbitrary waveform which lies above or below

some particular reference voltage level and that selected part of the waveform is used for

transmission. So they are referred as voltage limiters, current limiters, amplitude selectors

or slicers. There are three different types of clipping circuits.

1) Positive Clipping circuit.

2) Negative Clipping.

3) Positive and Negative Clipping (slicer).

In positive clipping circuit positive cycle of Sinusoidal signal is clipped and

negative portion of sinusoidal signal is obtained in the output of reference voltage is added,

instead of complete positive cycle that portion of the positive cycle which is above the

reference voltage value is clipped. In negative clipping circuit instead of positive portion of

sinusoidal signal, negative portion is clipped. In slicer both positive and negative portions

of the sinusoidal signal are clipped.


32

Procedure


2. Connect the function generator at the input terminals and CRO at the output terminals of

the circuit.

3. Apply a sine wave signal of frequency 1 KHz, Amplitude greater than the reference

voltage at the input and observe the output waveforms of the circuits.

Circuit Diagram

Positive Clipper


33

Negative Clipper


34

Observations

Positive Clipper Negative Clipper

Unbiased Clipper

Vref = 0V Vref = 0V

Output voltage

(V)

Time Period

(ms)

Output voltage

(V)

Time Period

(ms)

Biased Clipper

Vref = 2V Vref = 2 V

Output voltage

(V)

Time Period

(ms)

Output voltage

(V)

Time Period

(ms)


35

Ex. No. 4b

CLAMPERS

Aim

To study the clamper circuits for different reference voltages and to verify the

responses.




1 CRO 1Hz-20MHz 1 1 Resistor 1KΩ 1

2 RPS (0–30) V 1 2 Capacitors 10µF 1

3 Bread

Board - 1

3 Diode IN4007 1 4 Connecting

Wires - Req

5 Function

Generator 1Hz-1MHz 1

Theory

A clamping circuit is one that takes an input waveform and provides an

output that is a faithful replica of its shape but has one edge tightly clamped to

the zero voltage reference point. There are various types of Clamping circuits, which

are mentioned below:

1. Positive Clamping Circuit.

2. Negative Clamping Circuit.

3. Positive Clamping with positive reference voltage.

4. Negative Clamping with positive reference voltage.

5. Positive Clamping with negative reference voltage.

6. Negative Clamping with negative reference voltage.

The input signal is a sinusoidal which begins at t=0. The capacitor C is charged at t = 0.

The waveform across the diode at various instant is studied. During the first quarter cycle

the input signal rises from zero to the maximum value Vm. The diode being ideal, no

forward voltage may appear across it. During this first quarter cycle the capacitor voltage

VA = Vi . The voltage across C rises sinusoidally, the capacitor is charged through the

series combination of the signal source and the diode. Throughout this first quarter cycle

the output V0 has remained zero. At the end of this quarter cycle there exists across the


36

capacitor a voltage VA = Vm. After the first quarter cycle, the peak has been passed and the

input signal begins to fall, the voltage VA across the capacitor is no longer able to follow the

input voltage. For in order to do so, it would be required that the capacitor discharge, and

because of the diode, such a discharge is not possible. The capacitor remains charged to the

voltage VA = Vm, and, after the first quarter cycle the output is V0 = Vi - Vm. During

succeeding cycles the positive excursion of the signal just barely reaches zero. The diode

need never again conduct, and the positive extremity of the signal has been clamped to zero.

The average value of the signal is -Vm.

Procedure


2. Connect the function generator at the input terminals and CRO at the output

terminals of the circuit.

3. Apply a sine wave signal of frequency 1 KHz, Amplitude greater than the reference

voltage at the input and observe the output waveforms of the circuits.

Circuit Diagram:

Negative

Clamper


37

Model Graph:

Input waveform Output Waveform

Positive Clamper


38

Model Graph:

Input waveform Output Waveform

Observations

Positive Clamper Negative Clamper

Unbiased Clamper

Vref = 0V Vref = 0V

Output voltage

(V)

Time Period

(ms)

Output voltage

(V)

Time Period

(ms)

Biased Clamper

Vref = 2V Vref = 2V

Output voltage

(V)

Time Period

(ms)

Output voltage

(V)

Time Period

(ms)


39

Result

Thus the clipper and clamper using diode was conducted and corresponding

waveforms are obtained.


40

Post Lab Questions

1. For the given clamper circuit find out the output voltage Vo where input is 5V

2. Differentiate +ve and -ve Clippers.

3. What is the function of Clampers?

4. Write the classifications of clippers and clampers.

5. Draw the output for the given input to the clamper circuit


41



Experiment No. :



Register Number :




(30)

Marks Obtained


2 Conduction 15



5 Total 40

Staff Signature


42

5. RC Phase Shift Oscillator

Pre Lab Questions

1. What are the applications of sinusoidal oscillator and non-sinusoidal oscillators?

2. What are the factors that affects stability and of an oscillators?

3. What is a phase shift oscillator?

4. What are the applications of RC phase shift oscillators?

5. Which oscillators are used to generate low frequency signals?


43

Ex.No. 5

DESIGN OF RC PHASE SHIFT OSCILLATOR

Aim

1. To design and construct RC phase shift oscillator, Wien bridge oscillator

2. Obtain a sinusoidal output and verify the practical frequency with calculated

theoretical frequency.

Apparatus Required

S. No. Apparatus Range Qty

1 RPS (0-30)V 1

2 CRO 1Hz-20MHz 1

3 Bread board 1 1

4 Transistor BC107 1

5

Capacitor

0.01µF

100 µF

3

1

6 Resistor

10KΩ

18KΩ

3.3KΩ

1KΩ

3

1

2

1

7 Connecting wires

Theory

Phase Shift Oscillator

The circuit arrangement of a phase shift oscillator using NPN transistor in CE

configuration consists of voltage divider R1- R2 which provide the necessary bias, RE and

CE combinations provide temperature stability and collector resistor RC controls the

collector voltage. The oscillator output voltage is coactively coupled to the load by CC.

In case of a transistor phase shift oscillator, the output of the feedback network is

loaded appreciably by the relatively small input resistance (hie) of the transistor. Hence

instead of employing voltage series feedback, voltage shunt feedback is used for a

transistor phase shift oscillator. In this circuit, the feedback signal is coupled through the

feedback resistor R’ in series with the amplifier stage input resistance hie. The value of R’

should be such that when added with the amplifier stage input resistance hie it is equal to

R i.e., R’ + hie = R.


44

The circuit is set in to oscillations by any random or variation caused in the base

current, that may be due to noise inherent in the transistor or minor variation in voltage of

DC power supply. This variation in base current is amplified in collector circuit. The

output of the amplifier is supplied to an RC feedback network .The RC network produces

a phase shift of 180 between output and input voltages .Since CE amplifier produces a

phase reversal of the input signal ,total phase shift becomes 360 or 0 which is essential

for regeneration or for sustained oscillations. The output of this network is same as the

originally assumed input to the amplifier and is applied to the base terminal of the

transistor .Thus sustained variation in collector current between saturation and cutoff

values are obtained .RC phase shift network is the frequency determining network .

Design


F= 1/ (2 RC (6+4 (RC/R)))

R= 10 K RC =3.3 K F=5 KHz

5 x 10 3 = 1/ (2 10 x 10 3 x C x (6+(4 x (3.3 x 10 3/ 10 x 10 3))))

C = 0.001 F

VCE < V CC / 2

VCE < 10 / 2

VCE = 4V

Kirchoff’s Voltage law for output circuit:

VCC - VCE = IC RC + IE RE

IC IE = 2 mA

10 – 4 - IC(RC + RE) = 0

RC + RE = 6 x 10 3 / 2

RE = 1 K

To find R 1 and R 2 :

VB = VCCR2 /(R1 + R 2) (1)

Also VB = VBE + VE

VB = 0.7 + 2 = 2.7 For Silicon Transistor VBE =0.7

From equation (1)

2.7/10 = R2 /(R1 + R 2) (2)

S= 1 + (RB / RE) (S= 10)

RB = 9 K


45

RB = R1 R2 / (R1 + R2) (3)

Substituting (2) in (3)

9 = R1 (0.27)

R1 = 33 K R2 = 12K CE = 100 F

Circuit Diagrams


Precautions

1 Voltage knob of RPS should be kept at minimum position

2 Current knob of RPS should be kept at maximum position.


46

Procedure


1. Connections are made as per circuit diagram.

2. Collector voltage signal is monitored in the CRO.

3. The frequency is calculated from the waveform obtained.

4. Base voltage signal is monitored in the CRO to check for the phase shift.

5. The graphs are plotted for VCE Vs Time and VBE Vs Time.

Tabular Column


Amplitude

Voltage

(Vpp) Volts

Time Period

(ms)

Theoretical

frequency

(Hz)

Practical

frequency

(Hz)

Model Calculations


T =

f = 1 / T =

Model Graph

RC Phase Shift Oscillator

VCE

(Volts)

t (ms)

VBE

(Volts)

t (ms)


47

Result

Thus the RC Phase shift oscillator is designed and its oscillations are

obtained.


48

Post Lab Questions

1. What is the basic principle of RC oscillators?

2. Why RC oscillators cannot generate high frequency oscillations?

3. Why we need a phase shift between input and output signal?

4. How is phase angle determined in RC phase shift oscillator?

5. What is the drawback of phase shift oscillators?


49



Experiment No. :



Register Number :




(30)

Marks Obtained


2 Conduction 15



5 Total 40

Staff Signature


50

6.Frequency Response of voltage Series feedback amplifier

Pre Lab Questions

1. What is the difference between voltage and current feedback?

2. How do series and shunt feedback differ from each other?

3. What is effect of negative feedback on the gain input, output impedances,

bandwidth in an amplifier?

4. What is feedback pair?

5. What happens to the frequency distortion when negative feedback is applied?


51

Ex.No.6

FREQUENCY RESPONSE OF VOLTAGE-SERTES FEEDBACK AMPLIFIER

Aim

To study the effect of voltage series feedback on Gain of the Amplifier.

Apparatus Required

S.No. Apparatus Range Qty

1 RPS (0-30)V 1

2 CRO 1Hz-20MHz 1

3 Function Generator 1Hz-1MHz 1

4 Bread board - 1

5 Transistor BC

107

6 Capacitor 0.1µF

2.2µF

3 Resistor -

3.3kΩ,

3.3k Ω,

1.5kΩ,

1kΩ,

18k Ω,

560Ω

6 Connecting wires - As per

required

Theory

When any increase in the output signal results into the input in such a way as to

cause the decrease in the output signal, the amplifier is said to have negative feedback.

The advantages of providing negative feedback are that the transfer gain of the amplifier

with feedback can be stabilized against variations in the hybrid parameters of the

transistor or the parameters of the other active devices used in the circuit. The most

advantage of the negative feedback is there will be significant improvement in the

frequency response and in the linearity of the operation of the amplifier. This

disadvantage of the negative feedback is that the voltage gain is decreased.

In Voltage-Series feedback, the input impedance of the amplifier is decreased and

the output impedance is increased. Noise and distortions are reduced considerably.


52

Circuit Diagram

Precautions

1. While taking the observations for the frequency response, the input voltage

must be maintained constant at 20mV.

2. The frequency should be slowly increased in steps.

3. The three terminals of the transistor should be carefully identified.

4. All the connections should be correct.

Procedure

1. Connections are made as per circuit diagram.

2. Keep the input voltage constant at 20mV peak-peak and 1kHz frequency. For

different values of load resistance, note down the output voltage and calculate the

gain by using the expression

Av = 20log(V0 / Vi ) dB

3. Add the emitter bypass capacitor and repeat STEP 2, and observe the effect of

Feedback on the gain of the amplifier


53

4. For plotting the frequency, the input voltage is kept constant at 20mV peak-peak

and the frequency is varied from 100Hz to 1MHz.

5. Note down the value of output voltage for each frequency. All the readings are

tabulated and the voltage gain in dB is calculated by using expression

Av = 20log(V0 / Vi ) dB

6. A graph is drawn by taking frequency on X-axis and gain on Y-axis on semi log

graph sheet

7. The Bandwidth of the amplifier is calculated from the graph using the expression

Bandwidth B.W = f2 – f1.

Where f1 is lower cutt off frequency of CE amplifier

f 2 is upper cutt off frequency of CE amplifier

The gain-bandwidth product of the amplifier is calculated by using the expression

Gain-Bandwidth Product = 3-dB midband gain X Bandwidth.

Observations

Frequency Response with feedback:

S.NO Frequency (Hz) Input Voltage (Vi) Output

Voltage (Vo)

Gain in dB

20log(Vo/Vi)

1

2

3

4

5

6

7

8

9

10


54

Frequency Response without feedback:

S.NO Frequency (Hz) Input Voltage (Vi) Output

Voltage (Vo)

Gain in dB

20log(Vo/Vi)

1

2

3

4

5

6

7

8

9

10

Model Waveform

BAND WIDTH

3 db

f1 f2

Frequency (Hz)

V

o

l

t

a

g

e

g

a

i

n


55

Result

The effect of negative feedback (Voltage -Series Feedback) on the amplifier is

observed. The voltage gain and frequency response of the amplifier are obtained. Also

gain-bandwidth product of the amplifier is calculated.


56

Post Lab Questions

1. What is the principle of feedback?

2. What happens to frequency distortion when negative feedback is used?

3. What is difference between current and voltage feedback?

4. How do series and shunt feedback differ from each other?

5. Why voltage series feedback is mostly used in cascade amplifier?


57



Experiment No. :



Register Number :




(30)

Marks Obtained


2 Conduction 15



5 Total 40

Staff Signature


58

7. Adders, Subtractors and Flipflops

Pre Lab Questions:

1. Derive the logical expression for full adder using K-map.

2. Derive the logical expression for half adder using K-map.

3. Derive the logical expression for half subtractor using K-map.

4. What is the difference between Latch and Flip flop?

5. How can you convert SR flip flop to JK flip flop?


59

EX.NO.7.a ADDERS AND SUBTRACTORS

AIM:

To construct the circuits of adder & subtractor and verify their truth table.

APPARATUS REQUIRED:

S.No Name of the Apparatus Range Quantity

1. Digital IC trainer kit 1

2. Connecting wires As required

THEORY:

a) Half Adder:

A combinational circuit which performs the addition of two bits is called half

adder. The input variables designate the augend and the addend bit, whereas the

output variables produce the sum and carry bits.

b) Full Adder:

A combinational circuit which performs the arithmetic sum of three input bits is

called full adder. The three input bits include two significant bits and a previous

carry bit. A full adder circuit can be implemented with two half adders and one

OR gate.

c) Half Subtractor:

A combinational circuit which performs the subtraction of two bits is called half

subtractor. The input variables designate the minuend and the subtrahend bit,

whereas the output variables produce the difference and borrow bits.

d) Full Subtractor:

A combinational circuit which performs the subtraction of three input bits is called

full subtractor. The three input bits include two significant bits and a previous

borrow bit. A full subtractor circuit can be implemented with two half subtractors

and one OR gate.

PROCEDURE:

a) Half Adder:

1. Connect the circuit as per the circuit diagram

2. For various inputs, note the corresponding output.

3. Verify the truth table of half adder.

b) Full Adder:


5. For various inputs, not the corresponding output.

6. Verify the truth table of full adder.


60

c) Half Subtractor:


8. For various inputs, note the corresponding output

9. Verify the truth table of half subtractor

d) Full Subtractor:


11. For various inputs note the corresponding output

12. Verify the truth table of full subtractor

CIRCUIT DIAGRAM:

a) Half Adder:

TRUTH TABLE:

S.No: INPUT OUTPUT

A B S C

1. 0 0 0 0

2. 0 1 1 0

3. 1 0 1 0

4. 1 1 0 1

b) Full adder:

TRUTH TABLE:

S.No: INPUT OUTPUT

A B C SUM CARRY

1. 0 0 0 0 0

2. 0 0 1 1 0

3. 0 1 0 1 0

4. 0 1 1 0 1

5. 1 0 0 1 0

6. 1 0 1 0 1

7. 1 1 0 0 1

8. 1 1 1 1 1


61

c) Half Subtractor:

TRUTH TABLE:

S.No: INPUT OUTPUT

A B DIFF BORR

1. 0 0 0 0

2. 0 1 1 1

3. 1 0 1 0

4. 1 1 0 0


62

d) Full Subtractor:

TRUTH TABLE:

S.No: INPUT OUTPUT

A B C DIFF BORR

1. 0 0 0 0 0

2. 0 0 1 1 1

3. 0 1 0 1 1

4. 0 1 1 0 1

5. 1 0 0 1 0

6. 1 0 1 0 0

7. 1 1 0 0 0

8. 1 1 1 1 1

Resul

Thus the Adders & Subtractors were constructed and their truth tables were

verified.


63

EX.N0.7.b VERIFICATION OF LOGICAL EXPRESSION AND FLIP-

FLOPS

AIM:

To design a combinational circuit, to implement and verify the given logical

expression.

APPARATUS REQUIRED:




.

THEORY:

a)Logical Expression: A literal is the primed or unprimed variable. When a Boolean

function is implemented with logic gates, each literal in the function designates an input

to a gate and each term is implemented with a gate. The minimization of number of

literals and the number of terms results in a circuit with less equipments. It is not always

possible to minimize both simultaneously. Usually further criteria must be available.

The number of literals in a Boolean function can be minimized by algebraic manipulation.

The only method available is cut and try procedure employing the postulates, the basic

theorems and other manipulation method which becomes familiar with use.

b)Flip-flops:

RS Flip Flop:

The clocked RS flip flop consists of NAND gates and the output changes its state

with respect to the input on application of clock pulse. When the clock pulse is high the S

and R inputs reach the second level NAND gates in their complementary form. The Flip

Flop is reset when the R input high and S input is low. The Flip Flop is set when the S

input is high and R input is low. When both the inputs are high the output is in an

indeterminate state.

JK Flip Flop:

The indeterminate state in the SR Flip-Flop is defined in the JK Flip Flop. JK

inputs behave like S and R inputs to set and reset the Flip Flop. The output Q is ANDed

with K input and the clock pulse, similarly the output Q’ is ANDed with J input and the

Clock pulse. When the clock pulse is zero both the AND gates are disabled and the Q

and Q’ output retain their previous values. When the clock pulse is high, the J and K

inputs reach the NOR gates. When both the inputs are high the output toggles

continuously. This is called Race around condition and this must be avoided.

T Flip Flop:

This is a modification of JK Flip Flop, obtained by connecting both inputs J and K

inputs together. T Flip Flop is also called Toggle Flip Flop.

BOOLEAN LAWS:


64

1) A + 0 = A

2) A +1 = 1

3) A . 0 = 0

4) A . 1 = A

5) A + A =A

6) A + A = 1

7) A . A = A

8) A . A =0

9) A = A

10) A + AB = A

11) A + A B = A + B

12) (A + B)(A + C) = A + BC

DE-MORGAN’S THEOREM:

1) AB = + B

2) BA = . B

MINIMIZATION OF EXPRESSION:

AB + A(B+C) + B (B+C) = AB + AB + AC + BB + BC

= AB + AB + AC + B + BC

= AB + AB + AC + B (1+C) [1+C=1]

= AB + AB + AC + B [ A+A = A]

= AB + AC + B

= B (A+1) + AC [ 1+A=1]

= B+AC

LOGICAL DIAGRAM:

TRUTH TABLE:

A B C AC AC+B

0 0 0 0 0

0 0 1 0 0

0 1 0 0 1

0 1 1 0 1


65

1 0 0 0 0

1 0 1 1 1

1 1 0 0 1

1 1 1 1 1

PROCEDURE:

a) Logical expression:

1. Minimize the given expression using Boolean laws or K-map technique.

2. Design the expression using combinational circuit as shown in figure

3. Verify the output

b) Flip-Flops:

1. Connections are given as per the circuit diagrams.

2. For all the ICs 7th pin is grounded and 14th pin is given +5 V supply.

3. Apply the inputs and observe the status of all the flip flops.

CIRCUIT DIAGRAM:

a) RS Flip-flop:

CHARACTERISTIC TABLE:

S.No: INPUT

Qn

Qn+1 S R

1 0 0 0 0

2 0 0 1 1

3 0 1 0 0

4 0 1 1 0

5 1 0 0 1

6 1 0 1 1

7 1 1 0 X

8 1 1 1 X


66

b) JK Flip-flop:


S.No:

INPUT

Qn

Qn+1 J K

1 0 0 0 0

2 0 0 1 1

3 0 1 0 0

4 0 1 1 0

5 1 0 0 1

6 1 0 1 1

7 1 1 0 1

8 1 1 1 0

c) T Flip-flop:


67


S.No:

INPUT

T

Qn

Qn+1

1 0 0 0

2 0 1 0

3 1 0 1

4 1 1 0

Result

A circuit was designed to implement the given logical expression and flip – flops

and the output was verified.


68

Post Lab Questions:

1. What is half adder?

2. What is full adder?

3. What are half and full subtractor?

4. What are the characteristics of a clocked R-S flip flop?

5. Bubbled OR gate is equal to


69



Experiment No. :



Register Number :




(30)

Marks Obtained


2 Conduction 15



5 Total 40

Staff Signature


70

8.Design of Multiplexer and Demultiplexer

Pre Lab Questions:

1. What is a multiplexer?

2. What is demultiplexer?

3. Multiplexer is also called

4. Demultiplexer is also called

5. What is the difference between demultiplexer and decoder?


71

EX.NO:8 DESIGN OF MULTIPLEXER AND DEMULTIPLEXER

AIM: To construct the circuit of multiplexer and demultiplexer and to study their

working.

APPARATUS REQUIRED:




THEORY: A multiplexer is a combinational logic circuit, which can select any one of the

numbers of inputs and route it to a single output. Multiplexers are available with four,

eight and sixteen inputs and a single output. It is also called data selector. The basic

multiplexer has several data input lines and a single output line. The selection of a

particular input line is controlled by a set of selection lines. Normally, there are 2n input

lines and n selector lines whose bit combinations determine which input is selected.

Therefore, multiplexer is ‘many into one’ and it provides the digital equivalent of an

analog selector switch.

A demultiplexer has a single input and many outputs. The input to a demultiplexer

can be routed to any of the output channels. For this reason, a demultiplexer is also

known as data distributor. The selection of specific output line is controlled by the values

of n selection lines.

PROCEDURE:

a) Multiplexer: 1. Connect the circuit as per the circuit diagram.

2. For various inputs note the corresponding outputs.

3. Verify the truth table of multiplexer.

b) Demultiplexer:


2. For various inputs note the corresponding outputs.

3. Verify the truth table of demultiplexer.

Multiplexer:


72

TRUTH TABLE:

S.No:

SELECTION

INPUT OUTPUT

S1 S2 Y

1. 0 0 I0

2. 0 1 I1

3. 1 0 I2

4. 1 1 I3

Demultiplexer:


73

TRUTH TABLE:

S.No:

INPUT OUTPUT

S

1 S2 Din Y0 Y1 Y2 Y3

1. 0 0 0 0 0 0 0

2. 0 0 1 1 0 0 0

3. 0 1 0 0 0 0 0

4. 0 1 1 0 1 0 0

5. 1 0 0 0 0 0 0

6. 1 0 1 0 0 1 0

7. 1 1 0 0 0 0 0

8. 1 1 1 0 0 0 1

Result Multiplexer and demultiplexer circuits were constructed and their operations were

verified.


74

Post Lab Questions:

1. State some applications of multiplexer and demux.

2. Build a 4:1 mux using only 2:1 mux?

3. How to implement a Master Slave flip flop using a 2 to 1 mux?

`


75



Experiment No. :



Register Number :




(30)

Marks Obtained


2 Conduction 15



5 Total 40

Staff Signature


76

9.Design of Counters

Pre Lab Questions:

1. What are Counters and what are its types?

2. What are Ripple counters?

3. What are synchronous counters?

4. State the advantage of synchronous counter over asynchronous counters?

5. When two counters are cascaded, the overall MOD number is equal to the

_________of their individual MOD numbers.


77

EX.NO.9. DESIGN OF COUNTERS

AIM:

To construct a 4-bit asynchronous and synchronous counters.

APPARATUS REQUIRED:




.

THEORY:

Asynchronous counter is those in which clock pulse is given to the first flip-flop

and the flip-flop output transition serves as a source for triggering other flip-flops. The

flip-flops change one at a time in rapid succession, and the signal propagates through the

counter in a ripple fashion. Asynchronous decade counter is also called as ripple counter.

In a ripple counter the flip flop output transition serves as a source for triggering other flip

flops. In other words, the clock pulse inputs of all the flip flops are triggered not by the

incoming pulses but rather by the transition that occurs in other flip flops. The term

asynchronous refers to the events that do not occur at the same time. With respect to the

counter operation, asynchronous means that the flip flop within the counter are not made

to change states at exactly the same time, they do not because the clock pulses are not

connected directly to the clock input of each flip flop in the counter. Synchronous

counters are those in which simultaneous clock pulses are given to all the flip-flops.

PROCEDURE:


2. Note the output and verify the counter operation.


78

CIRCUIT DIAGRAM:

Asynchronous Ripple counter:

TRUTH TABLE:

D C B A

0 0 0 0

0 0 0 1

0 0 1 0

0 0 1 1

0 1 0 0

0 1 0 1

0 1 1 0

0 1 1 1

1 0 0 0

1 0 0 1

1 0 1 0

1 0 1 1

1 1 0 0

1 1 0 1

1 1 1 0

1 1 1 1


79

Synchronous Ripple counter:

TRUTH TABLE

A B C D

0 0 0 0

0 0 0 1

0 0 1 0

0 0 1 1

0 1 0 0

0 1 0 1

0 1 1 0

0 1 1 1

1 0 0 0

1 0 0 1

1 0 1 0

1 0 1 1

1 1 0 0

1 1 0 1

1 1 1 0

1 1 1 1


80

Result

Thus the synchronous and synchronous counters were designed and truth table

verified.


81

Post Lab Questions:

1. How many flip-flops are required to construct a decade counter?

2. What is MOD counter?

3. How many different states does a 3-bit asynchronous counter have?

4. State some applications of counters.


82



Experiment No. :



Register Number :




(40)

Marks Obtained


2 Conduction 15



5 Total 40

Staff Signature


83

EX.NO:10 SIMULATION OF DIGITAL LOGIC CIRCUITS USING VHDL

AIM: To design and simulate the digital logic circuits using Xilinix Software.

SOFTWARE REQUIRED:

XILINIX software and FPGA Trainer Kit

VHDL CODE:

AND GATE

library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

use IEEE.STD_LOGIC_ARITH.ALL;

use IEEE.STD_LOGIC_UNSIGNED.ALL;

entity and1 is

Port ( a : in STD_LOGIC;

b : in STD_LOGIC;

c : out STD_LOGIC);

end and1;

architecture data_flow of and1 is

begin

c<=a and b;

end data_flow;

#PACE: Start of PACE I/O Pin Assignments

NET "a" LOC = "p106" ;

NET "b" LOC = "p107" ;

NET "c" LOC = "p179" ;

NOR GATE

library IEEE;




entity nor1 is


b : in STD_LOGIC;

c : out STD_LOGIC);

end nor1;

architecture data_flow of nor1 is

begin

c<=a nor b;

end data_flow;


NET "a" LOC = "p106" ;


84

NET "b" LOC = "p107" ;

NET "c" LOC = "p179" ;

OR GATE library IEEE;




entity or2 is


b : in STD_LOGIC;

c : out STD_LOGIC);

end or2;

architecture data_flow of or2 is

begin

c<=a or b;

end data_flow;


NET "a" LOC = "p106" ;

NET "b" LOC = "p107" ;

NET "c" LOC = "p179" ;

XOR library IEEE;




entity xor1 is


b : in STD_LOGIC;

c : out STD_LOGIC);

end xor1;

architecture data_flow of xor1 is

begin

c<=a xor b;

end data_flow;


NET "a" LOC = "p106" ;

NET "b" LOC = "p107" ;

NET "c" LOC = "p179" ;

FULL ADDER

library IEEE;

use IEEE.std_logic_1164.all;

entity fa is

port (a : in std_logic;

b : in std_logic;

cin : in std_logic;

sum : out std_logic;

cout : out std_logic);

end fa;


85

-- description of fa using concurrent signal assignments

architecture rtl of fa is

begin

sum <= (a xor b) xor cin;

cout <= (a and b) or (cin and a) or (cin and b);

end rtl;


NET "a" LOC = "p106" ;

NET "b" LOC = "p107" ;

NET "cin" LOC = "p108" ;

NET "cout" LOC = "p187" ;

NET "sum" LOC = "p179" ;

JK FLIP FLOP

library IEEE;

Use IEEE.STD_LOGIC_1164.All;

Use IEEE.STD_LOGIC_ARITH.All;

Use IEEE.STD_LOGIC_UNSIGNED.All;

entity jkff is

Port (j : in std_logic;

k : in std_logic;

clk : in std_logic;

q : inout std_logic;

qbar : inout std_logic);

end jkff;

architecture data_flow of jkff is

signal s1,s2:std_logic;

begin

s1<=k and clk and q;

s2<=j and clk and qbar;

q<=s1 nor qbar;

qbar<=s2 nor q;

end data_flow;


NET "clk" LOC = "p116" ;

NET "j" LOC = "p106" ;

NET "k" LOC = "p107" ;

NET "q" LOC = "p179" ;

NET "qbar" LOC = "p187" ;

RESULT: Thus the above digital logic circuits are simulated and verified using Xilinix

software.


86

Documents

15EE209L- ANALOG AND DIGITAL CIRCUITS LAB RECORD …