343logic-design-lab-manual-10 esl38-3rd-sem-2011

LOGIC DESIGN LAB
MANUAL
ECE - 10ESL38
3rd Semester B.E.
Dept. of Electronics and Communications Engg.
CITY ENGINEERING COLLEGE
BANGALORE – 61.

2011
Manual Prepared by:
Mrs. Shalini Prasad, Sr. Lecturer, CEC
Mr. Vishvakiran RC, Lecturer, CEC

Logic Design Lab 2011 10ESL38

TABLE OF CONTENTS

Experiments Page No.

IC Pin Configurations 2

1. Boolean Expression realization using Logic gates 4

2. Half/Full Adder and Subtractor 7

3. a. Parallel Adder/ Subtractor 10

b. BCD to Excess-3 and Vice-versa 14

4. Binary to Gray Conversion and vice versa 16

5. MUX/DEMUX for arithmetic circuits 21

6. Comparators 27

7. Decoder Chip for LED Display 31

8. Priority Encoder 33

9. Flip-Flop verification 35

10. Counters 38

11. Shift Registers 50

12. Ring Counter/ Johnson Counter 55

13. Sequence Generator 57

Logic Design Lab Syllabus – 10ESL38 59

Possible Viva Questions 60

3rdSem, E&C Dept. 1 SP,VK


IC Pin configurations
Inverter (NOT Gate) - 7404LS 2-Input AND Gate - 7408LS

2-Input OR Gate - 7432LS 2-Input NAND Gate - 7400LS

2-Input NOR Gate - 7402LS 2-Input EX-OR Gate - 7486LS

3-Input NAND Gate - 7410LS 4-bit Binary Full Adder74LS83



Dual 4-Input NAND Gate - 7420LS Dual 4-input Multiplexer74153

4-Bit Magnitude Comparator - 7485 Decoders/Demultiplexer 74139

Shift Register - 7495 Synchronous Up/Down Counter– 74192

Decimal scalar - 7490 DualJK Flip-flop– 7476



Experiment No. 1

BOOLEAN EXPRESSION REALIZATION USING LOGIC GATES

Aim: – To Simplify and Realize Boolean expressions using logic gates/Universal gates.

Components Required: - IC 7408 (AND), IC 7404 (NOT), IC 7432 (OR),IC 7400
(NAND), IC 7402 (NOR),IC 7486 (EX-OR)

Procedure –

1. Verify that the gates are working.
2. Construct a truth table for the given problem.
3. Draw a Karnaugh Map corresponding to the given truth table.
4. Simplify the given Boolean expression manually using the Karnaugh Map.

A: Implementation Using Logic Gates
5. Realize the simplified expression using logic gates.
6. Connect VCC and ground as shown in the pin diagram.
7. Make connections as per the logic gate diagram.
8. Apply the different combinations of input according to the truth tables.
9. Check the output readings for the given circuits; check them against the truth tables.
10. Verify that the results are correct.

B. Implementation Using Universal Gates
11. Convert the AND-OR logic into NAND-NAND and NOR-NOR logic.
12. Implement the simplified Boolean expressions using only NAND gates, and then
using only NOR gates.
13. Connect the circuits according to the circuit diagrams, apply inputs according to
the truth table and verify the results.



Given Problem:

Truth Table:

A B C D Y
0 0 0 0 0
0 0 0 1 0
0 0 1 0 0
0 0 1 1 0
0 1 0 0 0
0 1 0 1 1
0 1 1 0 1
0 1 1 1 1
1 0 0 0 0
1 0 0 1 0
1 0 1 0 0
1 0 1 1 0
1 1 0 0 0
1 1 0 1 1
1 1 1 0 1
1 1 1 1 1

Switching Expression:

∑
π
Karnaugh Map Simplification:
K-Map for SOP K-Map for POS
CD CD
AB 00 01 11 10 AB 00 01 11 10
00 0 0 0 0
00
01 0 B
01 1 1 1 11 0
11 1 1 1 10 0 0 0 0
10 BC
BD C+D

Simplified Boolean Expression:

SOP form Y=f(A,B,C,D)=BC+BD

POS form Y=f(A,B,C,D)=B(C+D)



Expression Realization using Basic Gates:

C 1
7408 3
2 1
3
B 7432 Y=BC+BD
4 2
7408 6
D 5

B 1
7408 3 Y=B(C+D)
1
C 7432
3 2
D 2

Realization using only NAND gates: Realization using only NOR gates:

C 1 2
3 1 5
7400 B 7402
7402 4 Y=B(C+D)
2 9 3
8
6
B 7400 Y=BC+BD
4 10 8
7400 6 C 7402 10
D 5 D 9

Realization using only NOR gates:
2
11
C 7402 1
13
7402
3
12
5 8
5 7402' 4 7402' 10 Y=BC+BD
B 7402 4
6 9
6 2
7402' 1
8 3
10
D 7402
9

Realization using only NAND gates:
11 1
B 7400
13
7400' 3 Y=B(C+D)
1 2
12
C 7400 3 9
8
2 7400
10
4
6
D 7400
5



Experiment No. 2

HALF/FULL ADDER AND HALF/FULL SUBTRACTOR

Aim: – To realize half/full adder and half/full subtractor using Logic gates

Components Required: - IC 7408, IC 7432, IC 7486, IC 7404, etc.

Procedure: -

1. Verify that the gates are working.

2. Make the connections as per the circuit diagram for the half adder circuit, on the trainer

kit.

3. Switch on the VCC power supply and apply the various combinations of the inputs

according to the respective truth tables.

4. Note down the output readings for the half adder circuit for the corresponding

combination of inputs.

5. Verify that the outputs are according to the expected results.

6. Repeat the procedure for the full adder circuit, the half subtractor and full subtractor

circuits.

7. Verify that the sum/difference and carry/borrow bits are according to the expected

values.



A. Half Adder using Logic Gates:
Half Adder Using Basic Gates

1 A B S C
A 7486 3
B 2
0 0 0 0
1
7408 3 0 1 1 0
2
1 0 1 0

1 1 0 1

B. Full Adder Using Logic Gates

Full Adder Using Basic Gates
A B Cn-1 S C
0 0 0 0 0
0 0 1 1 0
0 1 0 1 0
0 1 1 0 1
1 0 0 1 0
1 0 1 0 1
1 1 0 0 1
1 1 1 1 1



C. Half Subtractor Using Logic Gates

Half Subtractor Using Basic Gates

A B D B

0 0 0 0

0 1 1 1

1 0 1 0
C
1 1 0 0

D. Full Subtractor Using Logic Gates

Full Subtractor Using Basic Gates
A B Cn-1 D B
0 0 0 0 0
0 0 1 1 1
0 1 0 1 1
0 1 1 0 1
1 0 0 1 0
1 0 1 0 0
1 1 0 0 0
1 1 1 1 1



Experiment No. 3

PARALLEL ADDER AND SUBTRACTOR USING 7483

Aim: –i. To realize Parallel Adder and Subtractor Circuits using IC 7483
ii. BCD to Excess-3 Code conversion and Vice Versa using IC7483

Components Required: - IC 7483, IC 7486, etc.

Procedure: -
1. Connect one set of inputs from A1 to A4 pins and the other set from B1 to B4, on

the IC 7483.

2.Connect the pins from S1 to S4 to output terminals.

3. Short S,C0 to XOR gate 1 input and other input take from C4 and obtain the

Output Carry Cout (Output Borrow Bout).

4. In order to Perform Addition take S=0.

5. In order to implement the IC 7483 as a subtractor, Take S=1, Apply the B input

through XOR gates (essentially taking complement of B).

6. Apply the inputs to the adder/ subtractor circuits as shown in the truth tables.

7. Check the outputs and note them down in the table for the corresponding inputs.

8. Verify that the outputs match with the expected results.

IC 7483 Pin Diagram

7483



A. IC 7483 as a Parallel Adder

Circuit Diagram:

VCC Output
Carry
A4 5 1
1 C4 7486'
3
Cout
A3 14
3 2

Input Data A A2
8 S4
15
A1 S3
10 2
S2
Data
1 6 Output
3 16 S1
7486 9
B4 2
4
7486
6
4 7483
Input Data B3 5
9
B 7486
8
7
B2 10
12
11
7486 11
B1 13
12
13

GND
C0
S=0

Truth Table:- 4-BIT Parallel Adder Using 7483 where S=0

Input Data A Input Data B Addition

A4 A3 A2 A1 B4 B3 B2 B1 Cout S4 S3 S2 S1

1 0 0 0 0 0 1 0 0 1 0 1 0

1 0 0 0 1 0 0 0 1 0 0 0 0

0 0 1 0 1 0 0 0 0 1 0 1 0

0 0 0 1 0 1 1 1 0 1 0 0 0

1 0 1 0 1 0 1 1 1 0 1 0 1

0 1 1 0 0 0 1 1 0 1 0 0 1

1 1 1 0 1 1 1 1 1 1 1 0 1

1 0 1 0 1 1 0 1 1 0 1 1 1



B. IC 7483 as a Parallel Subtractor

VCC Output
Circuit Diagram: Carry
A4 5 1
1 C4 7486'
3
Bout
A3 14
3 2

Input Data A A2
8 S4
15
A1 S3
10 2
S2
Data
1 6 Output
3 16 S1
7486 9
B4 2
4
7486
6
4 7483
Input Data B3 5
9
B 7486
8
7
B2 10
12
11
7486 11
B1 13
12
13

GND
C0
S=1
4-BIT Parallel Subtractor Using 7483 Where S=1

Truth Table:

Subtraction
Input Data A Input Data B
A4 A3 A2 A1 B4 B3 B2 B1 Bout S4 S3 S2 S1

1 0 0 0 0 0 1 0 0 0 1 1 0

1 0 0 0 1 0 0 0 0 0 0 0 0

0 0 1 0 1 0 0 0 1 1 0 1 0

0 0 0 1 0 1 1 1 1 1 0 1 0

1 0 1 0 1 0 1 1 1 1 1 1 1

0 1 1 0 0 0 1 1 0 0 0 1 1

1 1 1 0 1 1 1 1 1 1 1 1 1

1 0 1 0 1 1 0 1 1 1 1 0 1
Note: Bout = 1 for A<B; Bout = 0 for A>B;



Example

4bit adder operation using 7483
if control input S=0,addition can be performed
Ex: If
↓C0=0
A4 A3 A2 A1=1100
B4 B3 B2 B1=0011
then Sum,S4 S3 S2 S1 =1111
and C0 C4 = Cout.

4 bit subtraction operation using 7483 for A>B here S=1
A4 A3 A2 A1= 1001
B4 B3 B2 B1= 1101 (2's complement) of +3=0011
The end around carry is disregarded 1 0110
C0 C4 = Bout = 0

Difference, S4 S3 S2 S1 = 0110
2's complement method of subtraction can be performed, if S=1(i.e. C0=1).

Consider the above Example A4 A_A2 A_ 1001 and B4 B3 B2 B1= 0011
3 _ 1= _

1‟s Complement of B4 B3 B2 B1 is B4 B3 B2 B1= 1100

. _4 A3 A2 A1=
A ___ 1001
B4 B3 B2 B1= 1100 → (1's complement) of +3 = 0011 2‟s Complement
of
+1 ← C0=1(S&C0 shorted) B input = -B

The end around carry is disregarded 1 0110
C0 C4 = Bout = 0 +6

4 bit subtraction operation using 7483 for A<B here S=1

_4 A3 A2 A1=
A ___ 1110
B4 B3 B2 B1= 0000 → (1's complement) of +15 = 1111 2‟s Complement
+1 ← C0=1(S&C0 shorted) of
B input = -B

The end around carry is disregarded 0 1111 → (2's complement) of +1 = 0001
C0 C4 = Bout = 1

-1



C. BCD To Excess-3 And Vice-Versa Conversion Using 7483 Chip
I. BCD TO EXCESS-3 CONVERTER
Note: S = 0 and B3,B2,B1,B0 = 0011 vary the BCD input at A3,A2,A1,A0.
VCC
Circuit Diagram:
A3 5
1
A2 14 C4
X NC
3
Input Data A A1
8 E3
15
A0 E2
10 2
E1
Data
1 6 Output
3 16 E0
7486 9
B3 = 0 2

Input Data 4
6
4 7483
7486
B B2 = 0 5
9
8
7486 7
B1 = 1 10
12
11
7486 11
B0 = 1 13
12
13

GND
C0
S=0
BCD to XCS3 using 7483
Truth Table :

Consider Constant Value for B3B2B1B0 = 0011 and S=0
BCD Inputs Excess – 3 Outputs
A3 A2 A1 A0 E3 E2 E1 E0
0 0 0 0 0 0 1 1
0 0 0 1 0 1 0 0
0 0 1 0 0 1 0 1
0 0 1 1 0 1 1 0
0 1 0 0 0 1 1 1
0 1 0 1 1 0 0 0
0 1 1 0 1 0 0 1
0 1 1 1 1 0 1 0
1 0 0 0 1 0 1 1
1 0 0 1 1 1 0 0
1 0 1 0 X X X X
1 0 1 1 X X X X
1 1 0 0 X X X X
1 1 0 1 X X X X
1 1 1 0 X X X X
1 1 1 1 X X X X



II. EXCESS-3 to BCD CONVERTER
Note: S=1 and B3,B2,B1,B0 = 0011 vary the Excess-3 input at A3(E3),A2(E2),A1(E1),A0(E0).
Circuit Diagram: VCC

A3 5
1
A2 14 C4
X NC
3
Input Data A A1
8 D
15
A0 C
10 2
B
Data
1 6 Output
3 16 A
7486 9
B3 = 0 2

Input Data 4
6
4 7483
7486
B B2 = 0 5
9
8
7486 7
B1 = 1 10
12
11
7486 11
B0 = 1 13
12
13

GND
C0
S=1

Truth Table : XCS3 to BCD using 7483

Consider Constant Value for B3B2B1B0 = 0011 and S=1

Excess-3 Inputs BCD Outputs

E3 E2 E1 E0 A B C D

0 0 1 1 0 0 0 0

0 1 0 0 0 0 0 1

0 1 0 1 0 0 1 0

0 1 1 0 0 0 1 1

0 1 1 1 0 1 0 0

1 0 0 0 0 1 0 1

1 0 0 1 0 1 1 0

1 0 1 0 0 1 1 1

1 0 1 1 1 0 0 0

1 1 0 0 1 0 0 1



Experiment No. 4

BINARY TO GRAY CONVERTER AND VICE VERSA

Aim: – To realize:.
i. Binary to Gray Converter using logic gates.
ii. Gray to Binary Converter using logic gates.

Components Required: - IC 7486, etc.

Procedure: -

1.Verify that the gates are working properly.

2. Write the proper truth table for the given Binary to Gray converter.

3. Draw Karnaugh maps for each bit of output. Simplify the Karnaugh maps to get

simplified Boolean Expressions.

4. Make connections on the trainer kit as shown in the circuit diagram for the Binary

to Gray converter.

5. Apply the Binary inputs at B3-B0 pins, according to the truth table.

6. Check the outputs at the G3-G0 pins and note them down in the table for the

corresponding inputs.

7. Verify that the outputs match with the expected results.

8. Repeat the procedure to design, test and verify the working of a Grey to Binary

Converter.



A. Binary to Gray Converter.

Truth Table:
Binary Input Gray Code Output
B3 B2 B1 B0 G3 G2 G1 G0
0 0 0 0 0 0 0 0
0 0 0 1 0 0 0 1
0 0 1 0 0 0 1 1
0 0 1 1 0 0 1 0
0 1 0 0 0 1 1 0
0 1 0 1 0 1 1 1
0 1 1 0 0 1 0 1
0 1 1 1 0 1 0 0
1 0 0 0 1 1 0 0
1 0 0 1 1 1 0 1
1 0 1 0 1 1 1 1
1 0 1 1 1 1 1 0
1 1 0 0 1 0 1 0
1 1 0 1 1 0 1 1
1 1 1 0 1 0 0 1
1 1 1 1 1 0 0 0

Karnaugh Maps:

For G3: For G2:

G3 = B3



For G1: For G0:

Circuit:



B. Gray to Binary Converter

Truth Table
Gray Code Input Binary Output
G3 G2 G1 G0 B3 B2 B1 B0
0 0 0 0 0 0 0 0
0 0 0 1 0 0 0 1
0 0 1 1 0 0 1 0
0 0 1 0 0 0 1 1
0 1 1 0 0 1 0 0
0 1 1 1 0 1 0 1
0 1 0 1 0 1 1 0
0 1 0 0 0 1 1 1
1 1 0 0 1 0 0 0
1 1 0 1 1 0 0 1
1 1 1 1 1 0 1 0
1 1 1 0 1 0 1 1
1 0 1 0 1 1 0 0
1 0 1 1 1 1 0 1
1 0 0 1 1 1 1 0
1 0 0 0 1 1 1 1

Karnaugh Maps:

For B3: For B2:

B3 = G3



For B1: For B0:

Circuit:



Experiment No. 5

MUX/DEMUX FOR ARITHMETIC CIRCUITS
Aim: – To study IC 74153 and 74139 and to implement arithmetic circuits with them.

Components Required: - IC 74153, IC 74139, IC 7404, IC 7400, IC 7420,etc.

Procedure –
A. For MUX IC 74153
1.The Pin [16] is connected to + Vcc and Pin [8] is connected to ground.
2. The inputs are applied either to ‘A’ input or ‘B’ input.
3.If MUX ‘A’ has to be initialized, EA is made low and if MUX ‘B’ has to be
initialized, EB is made low.
4. Based on the selection lines one of the inputs will be selected at the
output, and thus the truth table is verified.
5.In case of half adder using MUX, apply constant inputs at (I0a, I1a, I2a,
I3a)and (I0b, I1b, I2b and I3b) as shown.
6.The corresponding values of select input lines, A and B (S1 and S0) are
changed as per table and the output is taken at Za as sum and Zb as
carry.
7.In this case, the inputs A and B are varied. Making Ea and Eb zero
andthe output is taken at Za, and Zb.
8.In case of Half Subtractor, connections are made according to the circuit,
Inputs are applied at A and B as shown, and outputs are taken at Za
(Difference) and Zb (Borrow). Verify outputs.
9.In full adder using MUX, the inputs are applied at Cn-1, An and Bn
according to the truth table. The corresponding outputs are taken at Sn
(pin Za) and Cn (pin Zb) and are verified according to the truth table.
10. In full subtractor using MUX, the inputs are applied at Cn-1, An and Bn
according to the truth table. The corresponding outputs are taken at
pin Za(Difference) and pin Zb(Borrow) and are verified according to the
truth table.



Half Adder Using 74153 Half Subtractor using 74153

Truth Table:

Inputs Half Adder Outputs Half Subtractor Outputs
A B Sum Carry Diff Borrow
0 0 0 0 0 0
0 1 1 0 1 1
1 0 1 0 1 0
1 1 0 1 0 0

Full Adder Using 74153 Full Subtractor using 74153



Truth Tables for Full Adder/Subtractor using 74153
Inputs Full Adder Outputs Full Subtractor Outputs
A B Cin/Bin S Cout D Bout
0 0 0 0
0 0 0
1 0 1 1
0 0 1
1 0 1 1
0 1 0
0 1 0 1
0 1 1
1 0 1 0
1 0 0
0 1 0 0
1 0 1
0 1 0 0
1 1 0
1 1 1 1
1 1 1

Procedure –
B. For DEMUX IC 74139
1. The Pin [16] is connected to + Vcc and Pin [8] is connected to ground.
2. The inputs are applied either to ‘A’ input or ‘B’ input.
3. If DEMUX ‘A’ has to be initialized, EA is made low and if DEMUX ‘B’
has to be initialized, EB is made low.
4. Based on the selection lines one of the inputs will be selected at the set
of outputs, and thus the truth table is verified.
5. In case of half adder using DEMUX,Ea is set to 0, the corresponding
values of select input lines, A and B (S1a and S0a) are changed as per
table and the output is taken at Sum and Carry. Verify outputs.
6. In case of Half Subtractor, connections are made according to the
circuit, Inputs are applied at A and B as shown, and outputs are taken
at Differenceand Borrow. Verify outputs.
7. In full adder using DEMUX, the inputs are applied at Cn-1, An and Bn
according to the truth table. The corresponding outputs are taken at
Sum and Carry, and are verified according to the truth table.
8. In full subtractor using DEMUX, the inputs are applied at Cn-1, An and
Bn according to the truth table. The corresponding outputs are taken at
Difference and Borrow as shown, and are verified according to the
truth table.



Half Adder Using 74139

Half Subtractor Using 74139

Truth Tables:
Inputs Half Adder Outputs Half Subtractor Outputs
A B Sum Carry Diff Borrow
0 0 0 0 0 0
0 1 1 0 1 1
1 0 1 0 1 0
1 1 0 1 0 0



Full Adder Using 74139

Full Subtractor Using 74139



Truth Tables:
Inputs Full Adder Outputs Full Subtractor Outputs
A B Cin/Bin S Cout D Bout
0 0 0 0
0 0 0
1 0 1 1
0 0 1
1 0 1 1
0 1 0
0 1 0 1
0 1 1
1 0 1 0
1 0 0
0 1 0 0
1 0 1
0 1 0 0
1 1 0
1 1 1 1
1 1 1



Experiment No. 6

ONE/TWO BITCOMPARATOR AND IC 7485

Aim: – To verify the truth tables for one bit and two bit comparators after constructing them
with basic logic gates, and to study the working of IC 7485.

Components Required: - IC 7404, IC 7408, IC 7486, IC 7432, IC 7485, etc.

Procedure –
A. Comparators Using Logic Gates:
1.Verify the working of the logic gates.
2.Make the connections as per the respective circuit diagrams.
3.Switch on Vcc.
4.Apply the inputs as per the truth tables.
5.Check the outputs and verify that they are according to the truth tables.

B. Study of IC 7485:
1.Write the truth table for an4-bit comparator.
2. Connect pin 16 to Vcc and pin 8 to GND for the ICs.
3.Apply the two inputs as shown; making sure that the MSB and LSB is correctly
connected.
4. Outputs are recorded at pin 2 (A<B), pin 4 (A>B), pin 3 (A=B) pins and are
verified as being according to the truth table.

A. One-Bit Comparator:
Circuit : Truth Table: 1bit Comparator

Inputs Outputs
A B A>B A=B A<B
0 0 0 1 0
0 1 0 0 1
1 0 1 0 0
1 1 0 1 0

B. Two-Bit Comparator:



Truth Table : 2bit Comparator
A1 A0 B1 B0 A>B A=B A<B
0 0 0 0 0 1 0
0 0 0 1 0 0 1
0 0 1 0 0 0 1
0 0 1 1 0 0 1
0 1 0 0 1 0 0
0 1 0 1 0 1 0
0 1 1 0 0 0 1
0 1 1 1 0 0 1
1 0 0 0 1 0 0
1 0 0 1 1 0 0
1 0 1 0 0 1 0
1 0 1 1 0 0 1
1 1 0 0 1 0 0
1 1 0 1 1 0 0
1 1 1 0 1 0 0
1 1 1 1 0 1 0

Karnaugh Maps:
For A>B: For A<B

For A=B



Circuit:

C. 4-Bit comparator using IC 7485
Pin Diagram:



Truth Table: 4bit Comparator
Input A Input B Output
A3 A2 A1 A0 B3 B2 B1 B0 A>B A<B A=B
0 0 0 0 0 0 0 1 0 1 0
0 1 0 1 0 0 1 1 1 0 0
1 0 1 0 1 0 1 0 0 0 1
0 0 1 1 0 1 1 0 0 1 0
0 1 0 0 1 0 0 0 0 1 0
1 1 0 1 1 0 1 1 1 0 0
0 1 1 0 0 1 1 0 0 0 1
1 1 1 1 1 1 1 0 1 0 0



Experiment No. 7

DECODER CHIP FOR LED DISPLAY

Aim: – Tostudy the use of a Decoder Chip (IC 7447) to drive a LED Display.

Components required: - IC 7447, 7-segment LED Display, etc.

Procedure: -

1. Test and verify that all the segments of the LED Display are working.

2. Make the circuit connections as shown in the circuit diagram.

3. Connect Pin 16 to Vcc and Pin 8 to GND.

4. Connect the input pinsof the 7-segment LED Display to the respective pins (A3-A0)

of the 7447 BCD to 7-Segment decoder driver chip.

5. Give the different BCD inputs according to the truth table, and observe the Decimal

outputs displayed on the 7-segment LCD Display.

6. Verify that the outputs match the expected results in the truth tables.

IC 7447 Pin Diagram



Circuit Diagram:

Output Table:

BCD inputs segment outputs
display
D C B A a b c d e f g
0 0 0 0 1 1 1 1 1 1 0

0 0 0 1 0 1 1 0 0 0 0

0 0 1 0 1 1 0 1 1 0 1

0 0 1 1 1 1 1 1 0 0 1

0 1 0 0 0 1 1 0 0 1 1

0 1 0 1 1 0 1 1 0 1 1

0 1 1 0 0 0 1 1 1 1 1

0 1 1 1 1 1 1 0 0 0 0

1 0 0 0 1 1 1 1 1 1 1

1 0 0 1 1 1 1 0 0 1 1

7-segment LED Display Schematic



Experiment No. 8

PRIORITY ENCODER

Aim: – Tostudy the use of a 10-line-to-4-Line Priority Encoder Chip (IC 74147).


Procedure: -

1. Make the connections as shown in the circuit diagram.

2. Connect Pin 16 of the IC to Vcc and Pin 8 to GND.

3. Connect the pins designated Inputs 1 through 9, to the input switches of the trainer kit.

4. Connect the Output pins designated A, B, C, D to the LED indicators of the trainer kit.

5. Provide the inputs to the encoder chip as shown in the truth table.

6. Observe the outputs on the LED indicators, and note down the results for the

respective inputs.

7. Verify that the outputs are as shown in the truth table.

IC 74147 Pin Diagram



Truth Table:

Decimal Input BCD Output Decimal
1 2 3 4 5 6 7 8 9 D C B A Value
1 1 1 1 1 1 1 1 1 1 1 1 1 0
0 1 1 1 1 1 1 1 1 1 1 1 0 1
X 0 1 1 1 1 1 1 1 1 1 0 1 2
X X 0 1 1 1 1 1 1 1 1 0 0 3
X X X 0 1 1 1 1 1 1 0 1 1 4
X X X X 0 1 1 1 1 1 0 1 0 5
X X X X X 0 1 1 1 1 0 0 1 6
X X X X X X 0 1 1 1 0 0 0 7
X X X X X X X 0 1 0 1 1 1 8
X X X X X X X X 0 0 1 1 0 9



Experiment No. 9

STUDY OF FLIP-FLOPS

Aim: – To study and verify the truth tables for J-K Master Slave Flip Flop, T-type and D-
Type Flip-Flops.


Procedure: -
1. Make the connections as shown in the respective circuit diagrams.
2. Apply inputs as shown in the respective truth tables, for each of the flip-flop circuits.
3. Check the outputs of the circuits; verify that they match that of the respective truth
tables.

A. J-K Master-Slave Flip-Flop

Circuit:

Truth Table :

Preset Clear J K Clock Status

0 1 X X X 1 0 Set
1 0 X X X 0 1 Reset
1 1 0 0 No Change

1 1 0 1 0 1 Reset

1 1 1 0 1 0 Set

1 1 1 1 Toggle



B. T-Type Flip-Flop

Circuit:

Truth Table :

Preset Clear T Clock

1 1 0
1 1 1



C. D-Type Flip-Flop

Circuit:

Truth Table:

Preset Clear D Clock

1 1 0 0 1
1 1 1 1 0



Experiment No. 10

STUDY OF COUNTERS

Aim: – Realization of 3-bit counters as a sequential circuit and Mod-N counter Design (7476,
7490, 74192, 74193)

Components Required: - IC 7476, IC 7490, IC 74192, IC 74193, IC 7400, IC 7408, IC
7416, IC 7432, etc.

Procedure: -
A. Counter Circuits using IC 7476
1. Make the connections as shown in the respective circuit diagrams.
2. Clock inputs are applied one by one at the clock I/P, and the outputs are
observed at QA, QB and QC pins of the 7476 ICs.
3. Verify that the circuit outputs match those indicated by the truth tables.
B. Study of Counters IC 74192, IC 74193
1. Connections are made as shown in the respective circuit diagrams, except for
the connection from the output of the NAND gate to the load input.
2. The data (0011) = 3 is made available at the data input pins designated A, B, C
and D respectively.
3. The Load pin is made LOW so that the data 0011 appears at QD, QC, QB and
QA respectively.
4. Now, the output of the NAND gate is connected to the Load input pin.
5. Clock pulses are applied to the “Count Up” pin, and truth table is verified for
that condition.
6. Next, the data (1100) =12 (for 12 to 5 counter) is applied at A, B, C and D and
the same procedure as explained above, is performed.
7. IC 74192 and IC 74193 have the same pin configurations. 74192 can be
configured to count between 0 and 9 in either direction. Starting value can be
any number between 0 and 9.



A. 3-bit Asynchronous Up Counter

Circuit Diagram:

Timing Diagram:

Truth Table:
Clock QC QB QA
0 0 0 0
1 0 0 1
2 0 1 0
3 0 1 1
4 1 0 0
5 1 0 1
6 1 1 0
7 1 1 1
8 0 0 0
9 0 0 1



B. 3-bit Asynchronous Down Counter

Circuit Diagram:

Timing Diagram:

Truth Table:
Clock QC QB QA
0 1 1 1
1 1 1 0
2 1 0 1
3 1 0 0
4 0 1 1
5 0 1 0
6 0 0 1
7 0 0 0
8 1 1 1
9 1 1 0



C. Mod-5 Asynchronous Counter

Circuit:

Timing Diagram:

Truth Table:

Clock QC QB QA
0 0 0 0
1 0 0 1
2 0 1 0
3 0 1 1
4 1 0 0
5 0 0 0



D. Mod-3 Asynchronous Counter

Circuit:

Timing Diagram:

Truth Table:
Clock QC QB QA
0 0 0 0
1 0 0 1
2 0 1 0
3 0 0 0
4 0 0 1
5 0 1 0



E. 3-bit Synchronous Counter
Circuit:

Timing Diagram:

Truth Table:
Clock QC QB QA
0 0 0 0
1 0 0 1
2 0 1 0
3 0 1 1
4 1 0 0
5 1 0 1
6 1 1 0
7 1 1 1
8 0 0 0
9 0 0 1



F. 4-bit Ripple Counter

Circuit:

Truth Table:

CLK QD QC QB QA

0 0 0 0 0

1 0 0 0 1

2 0 0 1 0

3 0 0 1 1

4 0 1 0 0

5 0 1 0 1

6 0 1 1 0

7 0 1 1 1

8 1 0 0 0

9 1 0 0 1

10 1 0 1 0

11 1 0 1 1

12 1 1 0 0

13 1 1 0 1

14 1 1 1 0

15 1 1 1 1



G. Mod-10 Ripple Counter

Circuit:

Truth Table

CLK QD QC QB QA

0 0 0 0 0

1 0 0 0 1

2 0 0 1 0

3 0 0 1 1

4 0 1 0 0

5 0 1 0 1

6 0 1 1 0

7 0 1 1 1

8 1 0 0 0

9 1 0 0 1

10 0 0 0 0



H. Decade Counter (using IC 7490)

Circuit:

Truth Table:

Clock QD QC QB QA
0 0 0 0 0
1 0 0 0 1
2 0 0 1 0
3 0 0 1 1
4 0 1 0 0
5 0 1 0 1
6 0 1 1 0
7 0 1 1 1
8 1 0 0 0
9 1 0 0 1
10 0 0 0 0



I. Mod-8 Counter (Using IC 7490)

Circuit:

Truth Table:

Clock QD QC QB QA
0 0 0 0 0
1 0 0 0 1
2 0 0 1 0
3 0 0 1 1
4 0 1 0 0
5 0 1 0 1
6 0 1 1 0
7 0 1 1 1
8 0 0 0 0
9 0 0 0 1



J. Presettable counter using IC 74192/IC 74193 to count up from 3 to 8

Circuit:

Truth Table:

Clock QD QC QB QA Decimal
0 0 0 1 1 3
1 0 1 0 0 4
2 0 1 0 1 5
3 0 1 1 0 6
4 0 1 1 1 7
5 1 0 0 0 8
6 0 0 1 1 3
7 0 1 0 0 4



K. Presettable counter using IC 74192/74193 to count down from 5 to 12

Circuit:

Implementation of 4-Input OR gate:

Truth Table:
Clock QD QC QB QA Decimal
0 0 1 0 1 5
1 0 1 1 0 6
2 0 1 1 1 7
3 1 0 0 0 8
4 1 0 0 1 9
5 1 0 1 0 10
6 1 0 1 1 11
7 1 1 0 0 12
8 0 1 0 1 5
9 0 1 1 0 6



Experiment No. 11

STUDY OF SHIFT REGISTERS

Aim: – To study IC 74S95, and the realization of Shift left, Shift right, SIPO, SISO, PISO,
PIPO operations using the same.


Procedure: -
A. Serial In-Parallel Out (Left Shift):
1. Make the connections as shown in the respective circuit diagram.
2. Make sure the 7495 is operating in Parallel mode by ensuring Pin 6 (Mode M)
is set to HIGH, and connect clock input to Pin 8 (Clk 2).
3. Apply the first data at pin 5 (D) and apply one clock pulse. We observe that
this data appears at pin 10 (QD).
4. Now, apply the second data at D. Apply a clock pulse. We now observe that
the earlier data is shifted from QD to QC, and the new data appears at QD.
5. Repeat the earlier step to enter data, until all bits are entered one by one.
6. At the end of the 4th clock pulse, we notice that all 4 bits are available at the
parallel output pins QA (MSB), QB, QC, QD (LSB).
7. Enter more bits to see there is a left shifting of bits with each succeeding clock
pulse.
B. Serial In-Parallel Out (Right Shift):
1. Make the connections as shown in the respective circuit diagram.
2. Make sure the 7495 is operating in SIPO mode by ensuring Pin 6 (Mode M) is
set to LOW, and connect clock input to Pin 9 (Clk 1).
3. Apply the first data at pin 1 (SD1) and apply one clock pulse. We observe that
this data appears at pin 13 (QA).
4. Now, apply the second data at SD1. Apply a clock pulse. We now observe that
the earlier data is shifted from QA to QB, and the new data appears at QA.
5. Repeat the earlier step to enter data, until all bits are entered one by one.
6. At the end of the 4th clock pulse, we notice that all 4 bits are available at the
parallel output pins QA through QD.
7. Enter more bits to see there is a right shifting of bits with each succeeding
clock pulse.



C. Serial In-Serial Out Mode:
1. Connections are made as shown in the SISO circuit diagram.
2. Make sure the 7495 is operating in SIPO mode by ensuring Pin 6 (Mode) is set
to LOW, and connect clock input to Clk 1(Pin 9).
3. The 4 bits are applied at the Serial Input pin (Pin 1), one by one, with a clock
pulse in between each pair of inputs to load the bits into the IC.
4. At the end of the 4th clock pulse, the first data bit, „d0‟ appears at the output pin
QD.
5. Apply another clock pulse, to get the second data bit „d1‟ at QD. Applying yet
another clock pulse gets the third data bit „d2‟ at QD, and so on.
6. Thus we see the IC 7495 operating in SISO mode, with serially applied inputs
appearing as serial outputs.

D. Parallel In-Serial Out Mode:
1. Connections are made as shown in the PISO circuit diagram.
2. Now apply the 4-bit data at the parallel input pins A, B, C, D (pins 2 through
5).
3. Keeping the mode control M on HIGH, apply one clock pulse. The data applied
at the parallel input pins A, B, C, D will appear at the parallel output pins QA,
QB, QC, QDrespectively.
4. Now set the Mode Control M to LOW, and apply clock pulses one by one.
Observe the data coming out in a serial mode at QD.
5. We observe now that the IC operates in PISO mode with parallel inputs being
transferred to the output side serially.

E. Parallel In-Parallel Out Mode:
1. Connections are made as shown in the PIPO mode circuit diagram.
2. Set Mode Control M to HIGH to enable Parallel transfer.
3. Apply the 4 data bits as input to pins A, B, C, D.
4. Apply one clock pulse at Clk 2 (Pin 8).
5. Note that the 4 bit data at parallel inputs A, B, C, D appears at the parallel
output pins QA, QB, QC, QDrespectively.



IC 7495 Pin Diagram:

A. SIPO Mode (Left Shift)
Circuit: Truth Table:

Serial
Clock QA QB QC QD
I/P

1 1 X X X 1
1
2 0 X X 1 0

3 1 X 1 0 1

4 1 1 0 1 1

B. SIPO MODE (Right Shift)

Serial
Clock QA QB QC QD
I/P

1 1 1 X X X

2 0 0 1 X X

3 1 1 0 1 X

4 1 1 1 0 1



C. SISO Mode


Serial
Clock QA QB QC QD
I/P
1 d0=0 0 X X X
2 d1=1 1 0 X X
3 d2=1 1 1 0 X
4 d3=1 1 1 1 0=d0
5 X X 1 1 1=d1
6 X X X 1 1=d2
7 X X X X 1=d3

D. PISO Mode


Mode Clk Parallel I/P Parallel O/P

A B C D QA QB QC QD

1 1 1 0 1 1 1 0 1 1

0 2 X X X X X 1 0 1

0 3 X X X X X X 1 0

0 4 X X X X X X X 1



E. PIPO Mode


Clk Parallel I/P Parallel O/P
A B C D QA QB QC QD
1 1 0 1 1 1 0 1 1



Experiment No. 12

RING COUNTER /JOHNSON COUNTER

Aim: – To design and study the operation of a ring counter and a Johnson Counter.


Procedure: -
1. Make the connections as shown in the respective circuit diagram for the Ring
Counter.
2. Apply an initial input (1000) at the A, B, C, D pins respectively.
3. Keep Select Mode = HIGH (1) and apply one clock pulse.
4. Next, Select Mode = LOW (0) to switch to serial mode and apply clock pulses.
5. Observe the output after each clock pulse, record the observations and verify that
they match the expected outputs from the truth table.
6. Repeat the same procedure as above for the Johnson Counter circuit and verify its
operation.

A. Ring Counter


Mode Clock QA QB QC QD
1 1 1 0 0 0
0 2 0 1 0 0
0 3 0 0 1 0
0 4 0 0 0 1
0 5 1 0 0 0
0 6 0 1 0 0



B. Johnson Counter


Mode Clock QA QB QC QD
1 1 1 0 0 0
0 2 1 1 0 0
0 3 1 1 1 0
0 4 1 1 1 1
0 5 0 1 1 1
0 6 0 0 1 1
0 7 0 0 0 1
0 8 0 0 0 0
0 9 1 0 0 0
0 10 1 1 0 0



Experiment No. 13

SEQUENCE GENERATOR

Aim: – To design and study the operation of a Sequence Generator.


Theory: -

In order to generate a sequence of length „S‟, it is necessary to use at least„N‟ number of
Flip-flops, in order to satisfy the condition .

The given sequence length S = 15
Therefore, N = 4

Note: There is no guarantee that the given sequence can be generated by 4 flip-flops. If the
sequence is not realizable by 4 flip-flops, we need to use 5 flip-flops, and so on.

Procedure:-
1. Truth table is constructed for the given sequence, and Karnaugh maps are drawn in
order to obtain a simplified Boolean expression for the circuit.
2. Connections are made as shown in the circuit diagram.
3. Mode M is set to LOW (0), and clock pulses are fed through Clk 1 (pin 9).
4. Clock pulses are applied at CLK 1 and the output values are noted, and checked
against the expected values from the truth table.
5. The functioning of the circuit as a sequence generator is verified.

Circuit:



Truth Table: Karnaugh Map:

O/p
Map
Clock QA QB QC QD
Value
D
15 1 1 1 1 1 0
7 2 0 1 1 1 0
3 3 0 0 1 1 0
1 4 0 0 0 1 1
8 5 1 0 0 0 0
4 6 0 1 0 0 0
2 7 0 0 1 0 1
9 8 1 0 0 1 1
12 9 1 1 0 0 0
6 10 0 1 1 0 1
11 11 1 0 1 1 0
5 12 0 1 0 1 1
10 13 1 0 1 0 1
13 14 1 1 0 1 1
14 15 1 1 1 0 1
1 1 1
1 1
1



Syllabus
LOGIC DESIGN LAB
(Common to EC/TC/EE/IT/BM/ML)
Sub Code :10ESL38 IA Marks : 25

Hrs/ Week : 03 Exam Hours : 03

Total Hrs.: Exam Marks : 50

NOTE: Use discrete components to test and verify the logic gates. LabView can be used for
designing the gates along with the above.

1. Simplification, realization of Boolean expressions using logic gates/Universal gates.
2. Realization of Half/Full adder and Half/Full Subtractors using logic gates.
3. (i)Realization of parallel adder/Subtractors using 7483 chip
(ii) BCD to Excess-3 code conversion and vice versausing 7483 chip.
4. Realization of Binary to Gray code conversion and vice versa
5. MUX/DEMUX – use of 74153, 74139 for arithmetic circuits and code converter.
6. Realization of One/Two bit comparator and study of 7485 magnitude comparator.
7. Use of Decoder chip to drive LED display.
8. Use of IC 74147 as Priority encoder.
9. Truth table verification of Flip-Flops:
(i) JK Master slave
(ii) T type
(iii) D type.
10. Realization of 3 bit counters as a sequential circuit and MOD – N counter design
(7476, 7490, 74192,74193).
11. Shift left; Shift right, SIPO, SISO, PISO, PIPO operations using 74S95.
12. Wiring and testing Ring counter/Johnson counter.
13. Wiring and testing of Sequence generator.

http://www.scribd.com/doc/62491691/Logic-Design-Lab-Manual-10ESL38-3rd-sem-2011



Possible Viva Questions
1. Define a logic gate.
2. What are basic gates?
3. Why NAND and NOR gates are called as universal gates.
4. State De-morgans theorem
5. Give examples for SOP and POS
6. Explain how transistor can be used as NOT gate
7. Explain AND and OR gate using diodes
8. Realize logic gates using NAND and NOR gates only
9. Define LSI, MSI , SSI
10. List the applications of EX-OR and EX~NOR gates
11. What is a truth table?
12. What is a half adder?
13. Differentiate between half adder and half subtractor
14. What is a full adder?
15. Differentiate between combinational and sequential circuits. Give examples
16. Give the applications of combinational and sequential circuits
17. Give the block diagram of sequential circuits
18. Define flip flop
19. What is an excitation table/functional table
20. Differentiate between flip flop and latch
21. What is race around condition?
22. How do you eliminate race around condition
23. Give the block diagram of parallel adders
24. What are BCD Give their applications or uses
25. What is minterm and maxterm?
26. Explain the working of 7483 adder chip. Explain how it can be used as EX-3 to
BCD conversion and vice versa
27. Define multiplexer/ data selector
28. What is a Demultiplexer?
29. Give the applications of mux and demux
30. What is a encoder and decoder
31. Compare mux and encoder
32. Compare demux and decoder
33. What is a priority encoder?
34. What is a code converter?
35. What are counters? Give their applications
36. Compare synchronous and asynchronous counters
37. What is a ripple counter?
38. What is modulus of a number?
39. What is a shift register?
40. Explain how a shift register can be used as ring and johnson counter
41. Give the applications of johnson and ring counters
42. What is an up counter and down counter?
43. What is common cathode and common anode LED?
44. What is LCD and LED.
45. What is a static and a dynamic display.
46. List the types of LCD's and LED's.
47. What does LS stand for, in 74LS00?
48. Mention the different logic families.
49. Which is the fastest logic?

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