EXP

Digital Electronics Lab Manual

DIGITAL ELECTRONICS LAB

EC-106(C-09)

Department of

DIPLOMA IN ELECTRONICS & COMMUNICATION ENGINEERING

Devineni Venkata Ramana & Dr.Hima Sekhar

MIC College of Technology

KANCHIKACHERLA2014-15

Name : ________________________________

Regd. No. : _____________________________

Class : ________________________________

Year : _________________________________

LIST OF EXPERIMENTSDIGITAL ELECTRONICS LAB

EXP. NO.INDEXPAGE NO.

1 Verify the truth tables of AND,OR,NOT,NAND,NOR and Exclusive OR(Using ICs)

2Develop NOT,OR and AND operations using universal gates

3Construct Half adder and verify its truth table

4Construct Full adder and verify its truth table

5Construct and verify the truth tables of NAND and NOR latches

6Verify the truth tables of RS,DT,and JK and MASTER-SLAVE JK flip-flops

7Verify the function of counter (ICs like 7490,7493,74160)

8Verify the function of shift register(ICs like 7495,74194 etc)

9Verify the truth table of digial comparator using IC 7485

10Construct and Verify the working of R-2R D\A converter.

11Construct and Verify the working of Multiplexer(Using IC 74153)

12Verify the working of Demltiplexers

13Study the read and write operation of IC 7489

14Design and simulate half adder,full adder circuits using workbench software etc,,

STUDENT NAME: REG NO:

BRANCH: YEAR:

S.NOEXPERIMENT NAMEDATESTAFF SIGNATUREREMARKS/ GRADE

1 Verify the truth tables of AND,OR,NOT,NAND,NOR and Exclusive OR(Using ICs)

2Develop NOT,OR and AND operations using universal gates

3Construct Half adder and verify its truth table

4Construct Full adder and verify its truth table

5Construct and verify the truth tables of NAND and NOR latches

6Verify the truth tables of RS,DT,and JK and MASTER-SLAVE JK flip-flops.

7Verify the function of counter (ICs like 7490,7493,74160)

8Verify the function of shift register(ICs like 7495,74194 etc)

9Verify the truth table of digial comparator using IC 7485

10Construct and Verify the working of R-2R D\A converter.

11Construct and Verify the working of Multiplexer(Using IC 74153)

12Verify the working of Demltiplexers

13Study the read and write operation of IC 7489

14Design and simulate half adder,full adder circuits using workbench software etc,.

Signature of Staff Member

EXP NO: 1 DATE:

1.VERIFY THE TRUTH TABLES OF AND,OR,NOT,NAND,NOR AND

EXCLUSIVE OR (USING ICS)AIM: To study the operations and verify the truth tables of Logic Gates AND, OR, NOT,NAND,NOR and Exclusive OR gates using ICs.

APPARATUS REQUIRED:

COMPONENTS:

1. IC 7408,7432 ,7404,7402 and 7486

EQUIPMENT:

1. IC Trainer Kit2. Connecting wires, Patch chordsTheory:

AND Gate:

The AND gate is an electronic circuit that gives a high output (1) only if all its inputs are high. A dot (.) is used to show the AND operation i.e. A.B. The logic symbol and its expression of AND Gate is shown in Fig. The IC 74LS08 is a two-input AND Gate IC it consists of 4-AND gates. The IC has 14 pins as shown in Fig. The truth table of AND Gate is as shown in table.

OR Gate:

The OR gate is an electronic circuit that gives a high output (1) if one or more of its inputs are high. A plus (+) is used to show the OR operation. The logic symbol and its expression of OR Gate are shown in Fig. The IC 74LS32 is a two in put OR Gate IC it consists of 4-OR gates. The IC has 14 pins as shown in Fig. The truth table of OR Gate is as shown in table.

NOT Gate:

When in put variable A is low the output of a NOT gate is High. The logic symbol of NOT Gate is shown in Fig .The IC 74LS04 is a single in put NOT Gate IC and it consists of 6-NOT gates. The IC has 14 pins constructed in Dual in Line package(DIP) as shown in Fig. The truth table of NOT Gate is as shown in Fig.

NAND Gate:

The outputs of all NAND gates are high if any of the inputs are low. The logic symbol of NAND Gate is shown in Fig .The IC 74 LS00 is a two input NAND Gate IC. It consists 4 NAND gates built in. The truth table of NAND Gate is as shown in Table.

NOR Gate:

The outputs of all NOR gates are low if any of the inputs are high. The logic symbol of NOR Gate is shown in Fig. The IC 74 LS02 is two in-put NOR Gate IC it consists of 4 NOR gates. The truth table of NOR Gate is as shown

EXOR Gate:

The 'Exclusive-OR' gate is a circuit which will give a high output if either, but not both, of its two inputs are high. . The logic symbol of EXOR Gate is shown in Fig .The IC 74LS04 is a single in put EXOR Gate IC and it consists of 4- EXOR gates. The truth table of EXOR Gate is as shown in Table.

PROCEDURE:

1. Construct the circuit on breadboard for each Gate as shown in figures by inserting the appropriate IC.

2. Check the combinations of various inputs as shown in truth tables for each Gate.

3. If the input is low connect input to Ground, which indicates logic 0.

4. If input is high or logic 1 then connect the input to the power supply.

5. When output is high the LED will glow which indicates output as high, if the LED is not glowing then the output is low.

Observations:

Truth Table for AND Gate

ABX = A*B

00

01

10

11

Truth Table for NOT Gate

AX =

0

1

Truth Table for OR Gate

ABX = A+B

00

01

10

11

Truth Table for EXOR Gate

ABX =

00

01

10

11

Truth Table for NOR Gate

ABX =

00

01

10

11

Truth Table for NAND Gate

ABX =

00

01

10

11

RESULT:

Successfully checked and verified the operation of Basic Logic Gates through the truth table. Signature of Staff Member

EXP NO: 2 DATE:

2.REALIZATION OF BASIC GATES USING UNIVERSAL GATESAIM: To realize the Basic gates AND- OR NOT using universal gates (NAND and NOR )Gates using ICs.

APPARATUS REQUIRED:

COMPONENTS:

1.IC 7400 AND 7402

EQUIPMENT:

1.Power supply

2.IC Trainer Kit3.Connecting Wires/Patch Chords

Realize OR gate using NAND Gate:

Realize AND gate using NAND Gate:

Realize AND gate using NOR Gate: Realize AND gate using NOR Gate:

PROCEDURE:1. Construct the circuit on breadboard for each Gate as shown in figures by inserting the appropriate IC.

2. Check the combinations of various inputs as shown in truth tables for each Gate.

3. If the input is low connect input to Ground, which indicates logic 0.

4. If input is high or logic 1 then connect the input to the power supply.

5. When output is high the LED will glow which indicates output as high, if the LED is not glowing then the output is low.

Observations:

Truth Table for NAND Gate

ABX = A*B

00

01

10

11

Truth Table for NOR Gate

ABX = A+B

00

01

10

11

RESULT:

Successfully realized Boolean expressions using AND-OR-NOT Gates, NAND and NOR gates and verified the operation through the truth tables.

Signature of Staff Member

EXP NO: 3 DATE:

REALISATION OF HALF ADDERAIM:

To construct and check the truth tables for Half-Adder. APPARATUS REQUIRED:COMPONENTS:

1. IC 7408

2. IC 7486

3. LED - 2 nos

4. 330 resistor-2 nos

EQUIPMENT:

1. Power supply

2. Bread Board.

3. Connecting wires

THEORY:HALF ADDER:LOGIC SYMBOL: A

S = AB+ AB

B

C = AB

The combinations for the sum and carry are written by the formula are given as.

S = AB+ AB

C = AB

PROCEDURE:

1. Connect the logic circuit diagram of Half adder on bread board as shown in figures.

2. Give power supply to pin no. 14 of each IC.

3. Ground the pin no 7 of each IC.

4. Connect LEDs as an out put for sum, carry, difference and barrow.

5. Connect a 330 resistor in series with each LED.

6. Check the truth table for all combinations.

7. When output is high the LED will glow, indicates logic 1.

8. When output is low the LED will not glow, indicates logic 0

CIRCUIT DIAGRAM:

TRUTH TABLE

ABSC C

00

01

10

11

PROCEDURE:

1 Connect the logic circuit diagram of Half adder on bread board as shown in figures.

2 Give power supply to pin no. 14 of each IC.

3 Ground the pin no 7 of each IC.

4 Connect LEDs as an out put for sum, carry, difference and barrow.

5 Connect a 330 resistor in series with each LED.

6 Check the truth table for all combinations.

7 When output is high the LED will glow, indicates logic 1.

8 When output is low the LED will not glow, indicates logic 0

RESULT:

Successfully constructed the Half-adder circuit using ICs and verified truth table.

Signature of Staff Member

EXP NO: 4 DATE:

REALISATION OF FULL ADDERAIM:

To construct and check the truth tables for Full-Adder. APPARATUS REQUIRED:COMPONENTS:

5. IC 7408

6. IC 7486

7. LED - 2 nos

8. 330 resistor-2 nos

EQUIPMENT:

4. Power supply

5. Bread Board.

6. Connecting wires

THEORY:The Full Adder circuit is used to add three binary digits. The two outputs are sum- S and carry-C. The three inputs are input A, input B and carry input C. The outputs are sum S and carry out X. The construction of Full adder using two EX-OR Gates, two AND Gates and one OR Gate is as shown in fig-3. The IC numbers are 7486, 7408 and 7432.

LOGIC SYMBOL: The combinations for the sum and carry are written by the formulae are given as.

S = ABC + ABC+ ABC + ABC

X = AB + BC + AC

PROCEDURE:1 Connect the logic circuit diagram of Full adder on bread board as shown in figures.

2 Give power supply to pin no. 14 of each IC.

3 Ground the pin no 7 of each IC.

4 Connect LEDs as an out put for sum, carry, difference and barrow.

5 Connect a 330 resistor in series with each LED.

6 Check the truth table for all combinations.

7 When output is high the LED will glow, indicates logic 1.

8 When output is low the LED will not glow, indicates logic 0

TRUTH TABLE FOR FULLADDER

ABCSumCarry

000

001

010

011

100

101

110

111

RESULT: Successfully constructed the Full-adder circuit using ICs and verified truth table.

Signature of Staff Member

EXP NO: 5 DATE:

NAND AND NOR LATCHESAIM:

To construct and verify the truth tables of Logic Gates NAND and NOR latches.

APPARATUS REQUIRED:

COMPONENTS:

2. IC 7400,7402

EQUIPMENT:

3. IC Trainer Kit

4. Connecting wires,Patch chords

LOGIC CIRCUITS:1.NAND LATCH:

TRUTH TABLE:INPUTSOUTPUTS

RSQNOT Q

00

01

10

11

2.NOR LATCH:

TRUTH TABLE:

INPUTSOUTPUTS

RSQNOT Q

00

01

10

11

PROCEDURE:1. Place the ICs on Trainer kit.2. Connect vcc and ground pins of ICs at +5v and ground pins of IC Trainer kit respectively3. Connections are made as per the logic circuit.4. Connect the input to the input switches and the outputs to the output LEDS provided in the IC Trainer kit.5. Apply clock pulse wherever necessary.6. Apply various combinations of inputs according to the truth table and observe the condition of LEDS.7. Hence , verify the truth table.RESULTS:

Signature of Staff Member

EXP NO: 6 DATE:

FLIP FLOPS : RS, JK,T,D, MASTER SLAVE FFAIM: To Study about Flip Flops and its applications.

APPARATUS REQUIRED:

COMPONENTS:

1. IC 7400

2. IC 7410

3. IC 7476

4. IC 7474

5. LED 2 no.s

6. Single lead probes.

EQUIPMENT:

1. Flipflop trainer kit2. Connecting wires/patch chords.

THEORY:

A flip-flop has two stable states. One of the stable states is known as SET or LOGIC 1 where as the other stable is called RESET, CLEAR or LOGIC 0. It stores a binary digit either 0 or 1.

Types of flip-flops:

1) SR flip flop

2) JK flip flop

3) D flip- flop

4) T flip-flop

S-R Flip-flop. When S=1 and R=0 after applying of clock pulse Q=1 and = 0,this state is know as set condition. When S=0 and R=1 when clock pulse is high Q=0 and = 1,this is reset condition. For the combination S=0 and R=0 the outputs will be the previous outputs only. The combination S=1 and R=1 are not applied because the outputs will be toggling mode i.e. Outputs are not stable.

JK Flip-flop

The construction of JK flip-flop using NAND gates is shown in fig-.

When clock is applied if J=1 and K=0 then the outputs Q=1 and =0 this condition is called as SET. If J=0 and K=1 then the outputs Q=0 and =1 this is called as reset condition. The truth table for the J-K flip flop is shown below. The JK flip flop can also be constructed by using an IC 74LS76. The Pin Description for IC 7476 are shown below:

D Flip-flop

The Logic symbol of D flip-flop is shown in fig 9. When clock is applied if D=1 then the outputs Q=1 and =0. If D=0 then the outputs Q=0 and =1. The truth table for the D flip flop is shown below. The D flip flop IC number is 74LS76. The Pin Description for IC 7476 are shown below:

T Flip-flop

WORK PROCEDURE:

1. Connections are made as per the logic symbols

2. Connect the logic input to input switches and logic outputs to o/p switches provided on the FlipFlop Trainer kit

3. Apply clock iput to the pulser of trainer kit.

4. Set the synchronous inputs Reset/Clear and set/preset to logic 1 throughout the experiment for all the flipflops

5. Switch on the trainer kit

6. Apply various combination of inputs according to the truth tables and observe the condition of LEDs

7. Hence verify the truth tables for all flipflops. TRUTH TABLE FOR

JK MASTER SLAVE FLIP FLOP

JKQn+1

00

01

10

11

Observations:

TRUTH TABLE FOR SR FLIP FLOP

SRQn+1

00

01

10

11

TRUTH TABLE FOR

D FLIP FLOP

DQn+1

0

1

TRUTH TABLE FOR

T FLIP FLOP

TQn+1

0

1

RESULT:

Successfully constructed various flip-flops and verified their truth tables.

Signature of Staff Member

EXP NO: 7 DATE:

COUNTERSAIM: To construct and check the Decade counter, Ripple counter and binary counters using IC 7490 and IC 7493.

APPARATUS REQUIRED:

COMPONENTS:

1. IC 7490

2. IC 7493

3. Resistors - 330 -- 8 nos.

4. LEDs -- 4 nos

5. Single lead probes.

EQUIPMENT:

1. Power supply

2. Bread Board.

PRINCIPLE:

7490 decade (0-9) ripple counter &7493 4-bit (0-15) ripple counter

These are ripple counters. The Counter outputs respond to a clock pulse. The count advances as the clock input becomes low (on the falling-edge), this is indicated by the bar over the clock label. This is the usual clock behaviour of ripple counters and it means a counter output can directly drive the clock input of the next counter in a chain.

The counter is in two sections: clock A-Q3 and clock B- Q2-Q1-Q0. For normal use connect QA to clock B to link the two sections, and connect the external clock signal to clock A. For normal operation at least one reset 0 input should be low, making both high resets the counter to zero (0000, Q3-Q0 low). The 7490 has a pair of reset 9 inputs on pins 6 and 7, these reset the counter to nine (1001) so at least one of them must be low for counting to occur. Counting to less than the maximum (9 or 15) can be achieved by connecting the appropriate output(s) to the two reset0 inputs. If only one reset input is required the two inputs can be connected together. For example: to count 0 to 8 connect Q3 (1) and Q0 (8) to the reset inputs.

IC 74LS 90 is used to count up to 9, ie.0 to 9 or 10 numbers. By applying input pulses manually the output will be a number in the form of glowing LEDs. The sequence of counting is as shown in table -.Decade Counting

Clk I/PPresent State

Q3Q2Q1Q0Next StateQ3Q2Q1Q0Decimal Number

10 0 0 00 0 0 1 1

20 0 0 10 0 1 02

30 0 1 00 0 1 13

40 0 1 10 1 0 04

50 1 0 00 1 0 15

60 1 0 10 1 1 06

70 1 1 00 1 1 17

80 1 1 11 0 0 08

91 0 0 01 0 0 19

101 0 0 10 0 0 00

PROCEDURE:

1. Setup the circuit as shown in fig-.

2. Now apply input signals at point A input manually (trigger pulses) and note sequence of counting and check the outputs as given in the table.

Counting

Clk I/PPresent State

Q3 Q2 Q1 Q0Next StateQ3 Q2Q1Q0Decimal Number

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

PRECAUTIONS:

1. Always use a straight lead probe to insert into the breadboard.

2. Apply proper grounding for ICs.

3. Check the starting pin number for each IC indicated with a dot as starting pin.

4. Use IC remover to remove IC from breadboard to avoid damage of pins of IC.

5. Dont touch the pins of ICs while power on.

6. Dont bend the pins of ICs.

7. Insert the components into the breadboard firmly.

8. Loose contact may result in error at output.

9. Give 1 level Voltage (+5V for TTL) or 0 level voltage to the inputs of the IC.

RESULT:

Successfully constructed the decade counter and observed the waveform and checked its counting sequences such as Even- Odd, Even and Odd.

Signature of Staff Member

EXP NO: 8 DATE:

SHIFT REGISTER(IC 7495,74194)

AIM:-

To study shift register using IC 7495 in all its modes i.e. SIPO/SISO, PISO/PIPO.APPARATUS REQUIRED: -

IC 7495, etc.Shift register trainer kit,

Connecting wires,patch cordsSerial In Parallel Out(SIPO):-

1. Connections are made as per circuit diagram.

2. Apply the data at serial i/p

3. Apply one clock pulse at clock 1 (Right Shift) observe this data at QA.

4. Apply the next data at serial i/p.

5. Apply one clock pulse at clock 2, observe that the data on QA will shift to

QB and the new data applied will appear at QA.

6. Repeat steps 2 and 3 till all the 4 bits data are entered one by one into the

shift register.

Serial In Serial Out(SISO):-

1. Connections are made as per circuit diagram.

2. Load the shift register with 4 bits of data one by one serially.

3. At the end of 4th clock pulse the first data d0 appears at QD.

4. Apply another clock pulse; the second data d1 appears at QD.

5. Apply another clock pulse; the third data appears at QD.

6. Application of next clock pulse will enable the 4th data d3 to appear at

QD. Thus the data applied serially at the input comes out serially at QD

Parallel In Serial Out (PISO):-

1. Connections are made as per circuit diagram.

2. Apply the desired 4 bit data at A, B, C and D.

3. Keeping the mode control M=1 apply one clock pulse. The data applied at

A, B, C and D will appear at QA, QB, QC and QD respectively.

4. Now mode control M=0. Apply clock pulses one by one and observe the

Data coming out serially at QD

Parallel In Parallel Out (PIPO):-

1. Connections are made as per circuit diagram.

2. Apply the 4 bit data at A, B, C and D.

3. Apply one clock pulse at Clock 2 (Note: Mode control M=1).

4. The 4 bit data at A, B, C and D appears at QA, QB, QC and QD

respectively.Circuit diagram :-

PISO:- RESULT:-

Signature of Staff Member EXP NO: 9 DATE:

DIGITAL COMPARATORS(IC 7485)AIM: i) To construct a Comparator using IC-7485 and to compare 2 BCD numbers in terms of their Magnitude.APPARATUS REQUIRED:

COMPONENTS:

1. IC-7485

EQUIPMENT:

1. IC Trainer Kit

2. IC7485

3. Connecting wires/Patch chords

.

THEORY:The comparison of two numbers is an operator that determine one number is greater than, less than (or) equal to the other number. A magnitude comparator is a combinational circuit that compares two numbers A and B and determine their relative magnitude. The outcome of the comparator is specified by three binary variables that indicate whether A>B, A=B (or) A