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EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

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Page 1: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

EKT 121 / 4ELEKTRONIK DIGIT 1

CHAPTER 1 : INTRODUCTION

Page 2: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

1.0 Number & Codes

Digital and analog quantities Decimal numbering system (Base 10) Binary numbering system (Base 2) Hexadecimal numbering system (Base 16) Octal numbering system (Base 8) Number conversion Binary arithmetic 1’s and 2’s complements of binary numbers

Page 3: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Signed numbers Arithmetic operations with signed numbers Binary-Coded-Decimal (BCD) ASCII codes Gray codes Digital codes & parity

Page 4: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Digital and analog quantities

Two ways of representing the numerical values of quantities : i) Analog (continuous) ii) Digital (discrete)

Analog : a quantity represented by voltage, current or meter movement that is proportional to the value that quantity

Digital : the quantities are represented not by proportional quantities but by symbols called digits

Page 5: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Digital and analog systems

Digital system: combination of devices designed to manipulate logical

information or physical quantities that are represented in digital forms

include digital computers and calculators, digital audio/video equipments, telephone system.

Analog system: contains devices manipulate physical quantities that are

represented in analog form audio amplifiers, magnetic tape recording and playback

equipment, and simple light dimmer switch

Page 6: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Analog Quantities

• Continuous values

Page 7: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Digital Waveform

Page 8: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Introduction to Numbering Systems

We are all familiar with the decimal number system (Base 10). Some other number systems that we will work with are:

Binary Base 2 Octal Base 8 Hexadecimal Base 16

Page 9: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Number Systems

0 ~ 9

0 ~ 1

0 ~ 7

0 ~ F

Decimal

Binary

Octal

Hexadecimal

Page 10: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Characteristics of Numbering Systems

1) The digits are consecutive.2) The number of digits is equal to the size of the

base.3) Zero is always the first digit.4) When 1 is added to the largest digit, a sum of zero

and a carry of one results.5) Numeric values determined by the implicit

positional values of the digits.

Page 11: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

00000000000000010000001000000011000001000000010100000110000001110000100000001001000010100000101100001100000011010000111000001111

000001002003004005006007010011012013014015016017

0123456789ABCDEF

0123456789

101112131415

BinaryOctalHexDecNUMBER SYSTEMS

Page 12: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Significant Digits

Binary: 11101101

Most significant digit Least significant digit

Hexadecimal: 1D63A7A

Most significant digit Least significant digit

Page 13: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Binary Number System

Also called the “Base 2 system” The binary number system is used to model the

series of electrical signals computers use to represent information

0 represents the no voltage or an off state 1 represents the presence of voltage or an

on state

Page 14: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Binary Numbering ScaleBase 2 Number Base 10 Equivalent Power Positional Value

000 0 20 1

001 1 21 2

010 2 22 4

011 3 23 8

100 4 24 16

101 5 25 32

110 6 26 64

111 7 27 128

Page 15: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Octal Number System

Also known as the Base 8 System Uses digits 0 - 7 Readily converts to binary Groups of three (binary) digits can be used to

represent each octal digit Also uses multiplication and division

algorithms for conversion to and from base 10

Page 16: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Hexadecimal Number System

Base 16 system Uses digits 0-9 &

letters A,B,C,D,E,F Groups of four bits

represent eachbase 16 digit

Page 17: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Number Conversion

Any Radix (base) to Decimal Conversion

Page 18: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Number Conversion Binary to Decimal Conversion

Page 19: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Binary to Decimal Conversion

Convert (10101101)2 to its decimal equivalent:

Binary 1 0 1 0 1 1 0 1

Positional Values

xxxxxxxx2021222324252627

128 + 32 + 8 + 4 + 1Products

17310

Page 20: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Octal to Decimal Conversion

Convert 6538 to its decimal equivalent:

6 5 3xxx

82 81 80

384 + 40 + 3

42710

Positional Values

Products

Octal Digits

Page 21: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Hexadecimal to Decimal Conversion

Convert 3B4F16 to its decimal equivalent:

Hex Digits 3 B 4 Fxxx

163 162 161 160

12288 +2816 + 64 +15

15,18310

Positional Values

Products

x

Page 22: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Number Conversion Decimal to Any Radix (Base)

Conversion

1. INTEGER DIGIT: Repeated division by the radix & record the remainder

2. FRACTIONAL DECIMAL:Multiply the number by the radix until the answer is in integer

Example:25.3125 to Binary

Page 23: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Decimal to Binary Conversion

2 5 = 12 + 1 2

1 2 = 6 + 0 2

6 = 3 + 0 2

3 = 1 + 1 2

1 = 0 + 1 2 MSB LSB 2510 = 1 1 0 0 1 2

Remainder

Page 24: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Decimal to Binary Conversion

Carry . 0 1 0 10.3125 x 2 = 0.625 0 0.625 x 2 = 1.25 1

0.25 x 2 = 0.50 0

0.5 x 2 = 1.00 1

The Answer: 1 1 0 0 1.0 1 0 1

MSB LSB

Page 25: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Decimal to Octal Conversion

Convert 42710 to its octal equivalent:

427 / 8 = 53 R3 Divide by 8; R is LSD

53 / 8 = 6 R5 Divide Q by 8; R is next digit

6 / 8 = 0 R6 Repeat until Q = 0

6538

Page 26: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Decimal to Hexadecimal Conversion

Convert 83010 to its hexadecimal equivalent:

830 / 16 = 51 R14

51 / 16 = 3 R3

3 / 16 = 0 R3

33E16

= E in Hex

Page 27: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Number Conversion

Binary to Octal Conversion (vice versa)

1. Grouping the binary position in groups of three starting at the least significant position.

Page 28: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Octal to Binary Conversion

Each octal number converts to 3 binary digits

To convert 6538 to binary, just substitute code:

6 5 3

110 101 011

Page 29: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Number Conversion

Example: Convert the following binary numbers to

their octal equivalent (vice versa).

a) 1001.11112 b) 47.38

c) 1010011.110112

Answer:

a) 11.748

b) 100111.0112

c) 123.668

Page 30: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Number Conversion

Binary to Hexadecimal Conversion (vice versa)

1. Grouping the binary position in 4-bit groups, starting from the least significant position.

Page 31: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Binary to Hexadecimal Conversion

The easiest method for converting binary to hexadecimal is to use a substitution code

Each hex number converts to 4 binary digits

Page 32: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Number Conversion

Example: Convert the following binary numbers

to their hexadecimal equivalent (vice versa).a) 10000.12

b) 1F.C16

Answer:

a) 10.816

b) 00011111.11002

Page 33: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Convert 0101011010101110011010102 to hex using

the 4-bit substitution code :

0101 0110 1010 1110 0110 1010

Substitution Code

5 6 A E 6 A

56AE6A16

Page 34: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Substitution code can also be used to convert binary to octal by using 3-bit groupings:

010 101 101 010 111 001 101 010

Substitution Code

2 5 5 2 7 1 5 2

255271528

Page 35: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Binary Addition0 + 0 = 0 Sum of 0 with a carry of 0

0 + 1 = 1 Sum of 1 with a carry of 0

1 + 0 = 1 Sum of 1 with a carry of 0

1 + 1 = 10 Sum of 0 with a carry of 1

Example:

11001 111

+ 1101 + 11

100110 ???

Page 36: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Simple Arithmetic Addition Example:

100011002

+ 1011102

101110102

Substraction Example:

10001002

- 1011102

101102

Example:

5816

+ 2416

7C16

Page 37: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Binary Subtraction 0 - 0 = 0

1 - 1 = 0

1 - 0 = 1

10 -1 = 1 0 -1 with a borrow of 1

Example:

1011 101

- 111 - 11

100 ???

Page 38: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Binary Multiplication0 X 0 = 0

0 X 1 = 0 Example:

1 X 0 = 0100110

1 X 1 = 1 X 101

100110

000000

+ 100110

10111110

Page 39: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Binary Division

Use the same procedure as decimal division

Page 40: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

1’s complements of binary numbers Changing all the 1s to 0s and all

the 0s to 1s

Example: 1 1 0 1 0 0 1 0 1 Binary

number

0 0 1 0 1 1 0 1 0 1’s complement

Page 41: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

2’s complements of binary numbers

2’s complement Step 1: Find 1’s complement of the number

Binary # 110001101’s complement 00111001

Step 2: Add 1 to the 1’s complement00111001

+ 0000000100111010

Page 42: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Signed Magnitude Numbers

Sign bit

0 = positive

1 = negative

31 bits for magnitude

This is your basic

Integer format

110010.. …00101110010101

Page 43: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Sign numbers Left most is the sign bit

0 is for positive, and 1 is for negative Sign-magnitude

0 0 0 1 1 0 0 1 = +25sign bit magnitude bits

1’s complement The negative number is the 1’s

complement of the corresponding positive number

Example: +25 is 00011001 -25 is 11100110

Page 44: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Sign numbers 2’s complement

The positive number – same as sign magnitude and 1’s complement

The negative number is the 2’s complement of the corresponding positive number.

Example Express +19 and -19 ini. sign magnitudeii. 1’s complementiii. 2’s complement

Page 45: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Digital Codes BCD (Binary Coded Decimal) Code

1. Represent each of the 10 decimal digits (0~9) as a 4-bit binary code.

Example: Convert 15 to BCD.

1 5

0001 0101BCD

Convert 10 to binary and BCD.

Page 46: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Digital Codes ASCII (American Standard Code for

Information Interchange) Code

1. Used to translate from the keyboard characters to computer language

Page 47: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Digital Codes The Gray Code

Only 1 bit changes Can’t be used in

arithmetic circuits Binary to Gray Code

and vice versa.

Decimal Binary Gray Code

0 0000 0000

1 0001 0001

2 0010 0011

3 0011 0010

4 0100 0110

5 0101 0111

6 0110 0101

Page 48: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

3.0 LOGIC GATES

• Inverter (Gate Not)• AND Gate• OR Gate• NAND Gate• NOR Gate• Exclusive-OR and Exclusive-NOR• Fixed-function logic: IC Gates

Page 49: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Introduction

Three basic logic gates AND Gate – expressed by “ . “ OR Gates – expressed by “ + “ sign (not an ordinary

addition) NOT Gate – expressed by “ ‘ “ or “¯”

Page 50: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

NOT Gate (Inverter)

a) Gate Symbol & Boolean a) Gate Symbol & Boolean

EquationEquation

b) Truth Table (Jadual b) Truth Table (Jadual Kebenaran) Kebenaran) c) Timing Diagram (Rajah c) Timing Diagram (Rajah

Pemasaan)Pemasaan)

Page 51: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

OR Gate

a) Gate Symbol & Boolean a) Gate Symbol & Boolean EquationEquation

b) Truth Table (Jadual b) Truth Table (Jadual Kebenaran) Kebenaran)

c) Timing Diagram (Rajah c) Timing Diagram (Rajah Pemasaan)Pemasaan)

Page 52: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

AND Gate

a) Gate Symbol & Boolean a) Gate Symbol & Boolean EquationEquation

b) Truth Table (Jadual b) Truth Table (Jadual Kebenaran) Kebenaran)

c) Timing Diagram (Rajah c) Timing Diagram (Rajah Pemasaan)Pemasaan)

Page 53: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

NAND Gate

a) Gate Symbol, Boolean a) Gate Symbol, Boolean Equation Equation

& Truth Table& Truth Table

b) Timing Diagram b) Timing Diagram

Page 54: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

NOR Gate

a) Gate Symbol, Boolean a) Gate Symbol, Boolean Equation Equation

& Truth Table& Truth Table

b) Timing Diagram b) Timing Diagram

Page 55: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Exclusive-OR Gate

BABABA

a) Gate Symbol, Boolean a) Gate Symbol, Boolean Equation Equation

& Truth Table & Truth Table

b) Timing Diagram b) Timing Diagram

Page 56: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Examples : Logic Gates IC

NOT gateNOT gate AND gateAND gate

Note : x is referring to family/technology (eg : AS/ALS/HCT/AC etc.)

Page 57: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

4.0 BOOLEAN ALGEBRA

Boolean Operations & expression Laws & rules of Boolean algebra DeMorgan’s Theorems Boolean analysis of logic circuits Simplification using Boolean Algebra Standard forms of Boolean Expressions Boolean Expressions & truth tables The Karnaugh Map

Page 58: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Karnaugh Map SOP minimization Karnaugh Map POS minimization 5 Variable K-Map Programmable Logic

Page 59: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

•Boolean Operations & expression

Expression : Variable – a symbol used to represent logical

quantities (1 or 0)

ex : A, B,..used as variable Complement – inverse of variable and is indicated by

bar over variable

ex : Ā

Page 60: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Operation : Boolean Addition – equivalent to the OR operation

X = A + B

- Boolean Multiplication – equivalent to the AND operation X = A∙B

A

BX

A

BX

Page 61: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Laws & rules of Boolean algebra

Page 62: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Commutative law of addition

Commutative law of addition,

A+B = B+A

the order of ORing does not matter.

Page 63: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Commutative law of Multiplication

Commutative law of Multiplication

AB = BA

the order of ANDing does not matter.

Page 64: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Associative law of addition

Associative law of addition

A + (B + C) = (A + B) + C

The grouping of ORed variables does not matter

Page 65: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Associative law of multiplication

Associative law of multiplication

A(BC) = (AB)C

The grouping of ANDed variables does not matter

Page 66: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Distributive Law

A(B + C) = AB + AC

(A+B)(C+D) = AC + AD + BC + BD

Page 67: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules

1) A + 0 = A

In math if you add 0 you have changed nothing In Boolean Algebra ORing with 0 changes nothing

Page 68: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules

2) A + 1 = 1

ORing with 1 must give a 1 since if any input

is 1 an OR gate will give a 1

Page 69: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules

3) A • 0 = 0

In math if 0 is multiplied with anything you

get 0. If you AND anything with 0 you get 0

Page 70: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules

4) A • 1 = A

ANDing anything with 1 will yield the anything

Page 71: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules

5) A + A = A

ORing with itself will give the same result

Page 72: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules

6) A + A = 1

Either A or A must be 1 so A + A =1

Page 73: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules

7) A • A = A

ANDing with itself will give the same result

Page 74: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules

8) A • A = 0

In digital Logic 1 =0 and 0 =1, so AA=0 since one of the inputs must be 0.

Page 75: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules

9) A = A

If you not something twice you are back to the beginning

Page 76: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules

10) A + AB = A

Proof:

A + AB = A(1 +B)DISTRIBUTIVE LAW

= A∙1 RULE 2: (1+B)=1

= A RULE 4: A∙1 = A

Page 77: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules 11) A + AB = A + B

If A is 1 the output is 1 , If A is 0 the output is B

Proof:

A + AB = (A + AB) + AB RULE 10

= (AA +AB) + AB RULE 7

= AA + AB + AA +AB RULE 8

= (A + A)(A + B) FACTORING

= 1∙(A + B) RULE 6

= A + B RULE 4

Page 78: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Boolean Rules

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

PROOF

(A + B)(A +C) = AA + AC +AB +BC DISTRIBUTIVE LAW

= A + AC + AB + BC RULE 7

= A(1 + C) +AB + BC FACTORING

= A.1 + AB + BC RULE 2

= A(1 + B) + BC FACTORING

= A.1 + BC RULE 2

= A + BC RULE 4

Page 79: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

De Morgan’s Theorem,De Morgan’s Theorem,

Page 80: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Theorems of Boolean Algebra

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

Page 81: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Theorems of Boolean Algebra9) A = A

10) A + AB = A

11) A + AB = A + B

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

13) Commutative : A + B = B + A

AB = BA

14) Associative : A+(B+C) =(A+B) + C

A(BC) = (AB)C

15) Distributive : A(B+C) = AB +AC

(A+B)(C+D)=AC + AD + BC + BD

Page 82: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

De Morgan’s Theorems

16) (X+Y) = X . Y17) (X.Y) = X + Y

• Two most important theorems of Boolean Algebra were contributed by De Morgan.

• Extremely useful in simplifying expression in which product or sum of variables is inverted.

• The TWO theorems are :

Page 83: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Implications of De Morgan’s Theorem

(a) Equivalent circuit implied by theorem (16) (b) Alternative symbol for the NOR function (c) Truth table that illustrates DeMorgan’s Theorem

(a)

(b)

Input Output

X Y X+Y XY

0 0 1 1

0 1 0 0

1 0 0 0

1 1 0 0

(c)

Page 84: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Implications of De Morgan’s Theorem

(a) Equivalent circuit implied by theorem (17) (b) Alternative symbol for the NAND function (c) Truth table that illustrates DeMorgan’s Theorem

(a)

(b)

Input Output

X Y XY X+Y

0 0 1 1

0 1 1 1

1 0 1 1

1 1 0 0

(c)

Page 85: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

De Morgan’s Theorem ConversionStep 1: Change all ORs to ANDs and all ANDs to OrsStep 2: Complement each individual variable (short overbar)Step 3: Complement the entire function (long overbars)Step 4: Eliminate all groups of double overbars

Example : A . B A .B. C= A + B = A + B + C= A + B = A + B + C= A + B = A + B + C= A + B

Page 86: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

ABC + ABC (A + B +C)D

= (A+B+C).(A+B+C) = (A.B.C)+D

= (A+B+C).(A+B+C) = (A.B.C)+D

= (A+B+C).(A+B+C) = (A.B.C)+D

= (A+B+C).(A+B+C) = (A.B.C)+D

De Morgan’s Theorem Conversion

Page 87: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Examples: Analyze the circuit below

Y

1. Y=???2. Simplify the Boolean expression found in 1

Page 88: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Follow the steps list below (constructing truth table) List all the input variable combinations of 1 and 0

in binary sequentially Place the output logic for each combination of

input Base on the result found write out the boolean

expression.

Page 89: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Exercises: Simplify the following Boolean expressions

1. (AB(C + BD) + AB)C

2. ABC + ABC + ABC + ABC + ABC Write the Boolean expression of the following circuit.

Page 90: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Standard Forms of Boolean Expressions Sum of Products (SOP) Products of Sum (POS)

Notes: SOP and POS expression cannot have more than one variable combined in a term with an inversion bar There’s no parentheses in the expression

Page 91: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Standard Forms of Boolean Expressions Converting SOP to Truth Table

Examine each of the products to determine where the product is equal to a 1. Set the remaining row outputs to 0.

Page 92: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Standard Forms of Boolean Expressions

Converting POS to Truth Table Opposite process from the SOP expressions. Each sum term results in a 0. Set the remaining row outputs to 1.

Page 93: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Standard Forms of Boolean Expressions

BCACABCBACBAf ),,(

632),,( mmmCBAf

The standard SOP Expression All variables appear in each product term. Each of the product term in the expression is called as minterm. Example:

In compact form, f(A,B,C) may be written as

)6,3,2(),,( mCBAf

Page 94: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Standard Forms of Boolean Expressions

)()()(),,( CBACBACBACBAf

The standard POS Expression All variables appear in each product term. Each of the product term in the expression is called as maxterm. Example:

541),,( MMMCBAf

In compact form, f(A,B,C) may be written as

)5,4,1(),,( MCBAf

Page 95: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Standard Forms of Boolean Expressions

)()()()(),,( CBACBACBACBACBAf

Example:

Convert the following SOP expression to an equivalent POS expression:

Example:

Develop a truth table for the expression:

CBACBACABABCCBAf ),,(

Page 96: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

THE K-MAP

Page 97: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Karnaugh Map (K-Map)

Karnaugh Mapping is used to minimize the number of logic gates that are required in a digital circuit.

This will replace Boolean reduction when the circuit is large.

Write the Boolean equation in a SOP form first and then place each term on a map.

Page 98: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

• The map is made up of a table of every possible SOP using the number of variables that are being used.

• If 2 variables are used then a 2X2 map is used

• If 3 variables are used then a 4X2 map is used

• If 4 variables are used then a 4X4 map is used

• If 5 Variables are used then a 8X4 map is used

Karnaugh Map (K-Map)

Page 99: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

K-Map SOP Minimization

Page 100: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

A

A

B B

Notice that the map is going false to true, left to right and top to bottom

The upper right hand cell is A B if X= A B then put an X in that cell

A

A

B B

1

This show the expression true when A = 0 and B = 0

0 10 1

2 32 3

2 Variables Karnaugh Map

Page 101: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

If X=AB + AB then put an X in both of these cells

A

A

B B

1

1

From Boolean reduction we know that A B + A B = B

From the Karnaugh map we can circle adjacent cell and find that X = B

A

A

B B

1

1

2 Variables Karnaugh Map

Page 102: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

3 Variables Karnaugh Map

Gray Code

00 A B

01 A B

11 A B

10 A B

0 1

C C

0 10 1

2 32 3

6 76 7

4 54 5

Page 103: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

X = A B C + A B C + A B C + A B C

Gray Code

00 A B

01 A B

11 A B

10 A B

0 1

C C

Each 3 variable term is one cell on a 4 X 2 Karnaugh map

1 1

1 1

3 Variables Karnaugh Map (cont’d)

Page 104: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

X = A B C + A B C + A B C + A B C

Gray Code

00 A B

01 A B

11 A B

10 A B

0 1

C COne simplification could be

X = A B + A B

1 1

1 1

3 Variables Karnaugh Map (cont’d)

Page 105: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

X = A B C + A B C + A B C + A B C

Gray Code

00 A B

01 A B

11 A B

10 A B

0 1

C CAnother simplification could be

X = B C + B C

A Karnaugh Map does wrap around

1 1

1 1

3 Variables Karnaugh Map (cont’d)

Page 106: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

X = A B C + A B C + A B C + A B C

Gray Code

00 A B

01 A B

11 A B

10 A B

0 1

C CThe Best simplification would be

X = B

1 1

1 1

3 Variables Karnaugh Map (cont’d)

Page 107: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

On a 3 Variables Karnaugh Map• One cell requires 3 Variables

• Two adjacent cells require 2 variables

• Four adjacent cells require 1 variable

• Eight adjacent cells is a 1

Page 108: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

4 Variables Karnaugh Map

Gray Code

00 A B

01 A B

11 A B

10 A B

0 0 0 1 1 1 1 0

C D C D C D C D

0 1 3 20 1 3 2

4 5 7 64 5 7 6

12 13 15 1412 13 15 14

8 9 11 108 9 11 10

Page 109: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Gray Code

00 A B

01 A B

11 A B

10 A B

0 0 0 1 1 1 1 0

C D C D C D C D

1

1

1

1

1

1

X = ABD + ABC + CD

Now try it with Boolean reductions

Simplify : X = A B C D + A B C D + A B C D + A B C D + A B C D + A B C D

Page 110: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

On a 4 Variables Karnaugh map

• One Cell requires 4 variables

• Two adjacent cells require 3 variables

• Four adjacent cells require 2 variables

• Eight adjacent cells require 1 variable

• Sixteen adjacent cells give a 1 or true

Page 111: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Simplify :

Z = B C D + B C D + C D + B C D + A B C

Gray Code

00 A B

01 A B

11 A B

10 A B

00 01 11 10

C D C D C D C D

1 1 1 1

1 1

1 1

1 1

1

1

Z = C + A B + B D

Page 112: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Simplify using Karnaugh map

First, we need to change the circuit to an SOP expression

Page 113: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Y= A + B + B C + ( A + B ) ( C + D)

Y = A B + B C + A B ( C + D )

Y = A B + B C + A B C + A B D

Y = A B + B C + A B C A B D

Y = A B + B C + (A + B + C ) ( A + B + D)

Y = A B + B C + A + A B + A D + B + B D + AC + C D

Simplify using Karnaugh map (cont’d)

SOP expression

Page 114: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Gray Code

00 A B

01 A B

11 A B

10 A B

00 01 11 10

C D C D C D C D

1 1

1 1

1 1 1 1

Y = 1 Y = 1

1 1 1 1

1 1

1 1

Simplify using Karnaugh map (cont’d)

Page 115: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

K-Map POS Minimization

Page 116: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

3 Variables Karnaugh Map

Gray Code

0 0

0 1

1 1

1 0

0 1

ABC

0 10 1

2 32 3

6 76 7

4 54 5

Page 117: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

3 Variables Karnaugh Map (cont’d)

Page 118: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

4 Variables Karnaugh Map

0 0

0 1

1 1

1 0

0 0 0 1 1 1 1 0 A B

C D

0 1 3 20 1 3 2

4 5 7 64 5 7 6

12 13 15 1412 13 15 14

8 9 11 108 9 11 10

Page 119: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

4 Variables Karnaugh Map (cont’d)

Page 120: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

4 Variables Karnaugh Map (cont’d)

Page 121: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Mapping a Standard SOP expression Example:

Answer:Answer:

Mapping a Standard POS expression Example: Using K-Map, convert the following standard POS expression into a minimum SOP expression

Answer:Answer:

Y = AB + AC or standard SOP :

Karnaugh Map - Example

DCBADCBABCDACDBADCBADCBAY

CDADBY

ABCCBACBAY

)( CBAY

Page 122: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

K-Map with “Don’t Care” Conditions

Input Output

Example :

3 variables with output “don’t care (X)”

Page 123: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

K-Map with “Don’t Care” Conditions (cont’d)

4 variables with output “don’t care (X)”

Page 124: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

“Don’t Care” Conditions Example: Determine the minimal SOP using K-Map:

Answer:Answer:

DACBCDDCBAF ),,,(

14,15)D(5,12,13, 9,10)M(0,2,6,8, D)C,B,F(A,

K-Map with “Don’t Care” Conditions (cont’d)

Page 125: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Solution : 14,15)D(5,12,13, 9,10)M(0,2,6,8, D)C,B,F(A,

ABCD

00

01

11

10

00 01 11 10

0 1 1 0

1 X 1 0

X X X X

0 0 1 0

0 1 3 2

4 5 7 6

12 13 15 14

8 9 11 10

DACBCDDCBAF ),,,(

Minimum SOP expression is CD

ADBC

Page 126: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

Extra Exercise

Minimize this expression with a Karnaugh map

ABCD + ACD + BCD + ABCD

Page 127: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

5 variable K-map

5 variables -> 32 minterms, hence 32 squares required

Page 128: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

K-map Product of Sums simplification

Example: Simplify the Boolean function F(ABCD)=(0,1,2,5,8,9,10) in

(a) S-of-p (b) P-of-s

Using the minterms (1’s)F(ABCD)= B’D’+B’C’+A’C’D

Using the maxterms (0’s) and complimenting F Grouping as if they were minterms, then using De Morgen’s theorem to get F.

F’(ABCD)= BD’+CD+AB

F(ABCD)= (B’+D)(C’+D’)(A’+B’)

Page 129: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

5 variable K-map

Adjacent squares. E.g. square 15 is adjacent to 7,14,13,31 and its mirror square 11.

The centre line must be considered as the centre of a book, each half of the K-map being a page

The centre line is like a mirror with each square being adjacent not only to its 4 immediate neighbouring squares, but also to its mirror image.

Page 130: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

5 variable K-map

Example: Simplify the Boolean function

F(ABCDE) = (0,2,4,6,11,13,15,17,21,25,27,29,31)

Soln: F(ABCDE) = BE+AD’E+A’B’E’

Page 131: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

6 variable K-map

6 variables -> 64 minterms, hence 64 squares required

Page 132: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

ICS217-Digital Electronics - Part 1.5 Combinational Logic

Tutorial 1.5

1. Simplify the Boolean function F(ABCDE) = (0,1,4,5,16,17,21,25,29)

Soln: F(ABCDE) = A’B’D’+AD’E+B’C’D’

2. Simplify the following Boolean expressions using K-maps.

(a) BDE+B’C’D+CDE+A’B’CE+A’B’C+B’C’D’E’

Soln: DE+A’B’C’+B’C’E’

(b) A’B’CE’+A’B’C’D’+B’D’E’+B’CD’+CDE’+BDE’

Soln: BDE’+B’CD’+B’D’E’+A’B’D’+CDE’

(c) F(ABCDEF) = (6,9,13,18,19,27,29,41,45,57,61)

Soln: F(ABCDEF) = A’B’C’DEF’+A’BC’DE+CE’F+A’BD’EF

Page 133: EKT 121 / 4 ELEKTRONIK DIGIT 1 CHAPTER 1 : INTRODUCTION

END OF Chapter 1