Digital Electronics - Synchronous Sequential circuits Notes

Latches, Edge triggered Flip flops SR, JK, T, D and Master slave – Characteristic table and equation,

Application table, Synchronous counters, Design of synchronous counters, up/down counter,

Modulo–n counter, Decade counters.

Part- 1

Part-II

Multiple Choice Question and answer - Click Here

2 Marks - Click Here

Notes for Synchronous Sequential circuits- Click Here

Digital Electronics- Unit-1 Hand written Notes

EC216 -DIGITAL ELECTRONICS

UNIT-I  --> MINIMIZATION TECHNIQUES AND LOGIC GATES

Minimization Techniques: Boolean postulates and laws – De-Morgan‟s Theorem - Principle of

Duality - Boolean expression - Minimization of Boolean expressions –– Minterm – Maxterm - Sum

of Products (SOP) – Product of Sums (POS) – Karnaugh map Minimization – Don‟t care conditions

– Quine - Mc Cluskey method of minimization. Logic Gates: AND, OR, NOT, NAND, NOR,

Exclusive–OR and Exclusive–NOR Implementations of Logic Functions using gates, NAND–NOR

implementations




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EC3204 Digital Electronics Notes for all 5 units

Notes for all five units of Digital Electronics.................................................................

UNIT I  - Syllabus
NUMBER SYSTEM AND BASIC LOGIC            
Number systems – Binary, Octal, Hexadecimal, BCD, Excess 3, Complements Conversions and
Arithmetic. Boolean theorems, Boolean algebra – AND, OR, NOT, NAND & NOR operation,
Sum of Product and Product of Sum forms. Minimization – Kamaugh’s map, Tabular
Minimization Procedures.

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2 Mark Q & A - Click here to download the full document

UNIT II
 COMBINATIONAL CIRCUITS - Syllabus
Design of Logic gates. Design of Adder, Subtractor, Comparators, Code Converters, Encoders,
Decoders, Multiplexers and Demultiplexers. Function realization using Gates & Combinational
circuits.
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UNIT III
SYNCHRONOUS SEQUENTIAL CIRCUITS  - Syllabus
Flip flops – SR, D, JK and T. Analysis of Synchronous Sequential circuits, Design of
Synchronous Sequential circuits, Counters, Shift registers, State diagram, State reduction and
State assignment.

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To Download the unit-3 -2 Marks Q&A- Click Here
To Download the unit-3 Important Questions - Click Here
For Full Document of Register - Click Here
For Full Document of Counters- Click Here
For Full Document on Design of Seq Circuits- Click Here


UNIT IV
ASYNCHRONOUS SEQUENTIAL CIRCUIT - Syllabus
Stable Unstable states, Output Specifications, Cycles and Races, Race free assignments,
Reduction of State and Flow tables, Hazards.

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Video links for unit-4 - Click Here
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UNIT V
MEMEORY, PROGRAMMABLE LOGIC DEVICES AND LOGIC FAMILIES - Syllabus
Memories and PLD’s: ROM, PROM, EPROM, PLA, PLD, CPLD and FPGA. Digital logic
families: TTL, ECL, CMOS.

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To Download the Notes on PLA, PAL &  Othere PLDs -Click Here
To Download the Unit-5- 2 Mark Q& A - Click Here


To Download the Text Book "Morris Mano M., “Digital Circuits and Logic Design”, Prentice Hall of India, II Edition, 1996" - Click Here


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Digital Electronics ppt for all Chapters - Click Here

To download the "EC 3204 Digital Electronics May june 2013" Question paper - Click Here
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Digital Electronics- Mechatronics - Anna University Previous year Question papers

Digital electronics question papers particularly for Mechatronics department is hard to found out in Internet.

Here I had upload the 2013 Question papers of Digital Electronics.
(i.e.,)
EC 3204 Digital Electronics May june 2013  &
EC 3204 Digital Electronics Nov Dec 2012

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Digital Electronics Presentation for all chapters and Problems with Solutions

The Following file consists of 16 Presentations which covers almost all the portions and also included the solved 2 marks and 16 marks of the digital electronics....
Q-1 Convert the following decimal numbers to their binary equivalents:
(a) 37
(b) 14
(c) 167
(d) 72.45
(e) 0.4475
(f) 52
(g) 4097.188
(h) 2048.625

A-1 (a) 37

Q-1 A certain memory has capacity of 16K X 32. How many words does it store?

A-1 This memory consists of 16K words of 32 bits each. Therefore, the total number
of words contained in the memory is 16384 because 16 X 1024 = 16384. The bit
storage capacity of this memory is 16384 X 32 = 524288 bits.

Q-2 How many different addresses are required by the memory that contains 16K
words?

A-2 16384 addresses are required by the memory that contains 16K words.

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DE unit-5 - 2 Mark question and answers

1. Explain ROM
 A read only memory(ROM) is a device that includes both the decoder and the OR gates within a
single IC package. It consists of n input lines and m output lines. Each bit combination of the input
variables is called an address. Each bit combination that comes out of the output lines is called a
word. The number of distinct addresses possible with n input variables is 2n.

2. What are the types of ROM?
1.PROM 2.EPROM 3.EEPROM
3. Explain PROM.
 PROM (Programmable Read Only Memory) It allows user to store data or program. PROMs use the
fuses with material like nichrome and polycrystalline. The user can blow these fuses by passing
around 20 to 50 mA of current for the period 5 to 20μs.The blowing of fuses is called programming
of ROM. The PROMs are one time programmable. Once programmed, the information is stored
permanent.
4. Explain EPROM.
 EPROM(Erasable Programmable Read Only Memory) EPROM use MOS circuitry. They store 1’s and
0’s as a packet of charge in a buried layer of the IC chip. We can erase the stored data in the EPROMs
by exposing the chip to ultraviolet light via its quartz window for 15 to 20 minutes. It is not possible
to erase selective information. The chip can be reprogrammed.
 5. Explain EEPROM.
 EEPROM(Electrically Erasable Programmable Read Only Memory) EEPROM also use MOS circuitry.
Data is stored as charge or no charge on an insulated layer or an insulated floating gate in the
device. EEPROM allows selective erasing at the register level rather than erasing all the information
since the information can be changed by using electrical signals.
6. What is RAM?
Random Access Memory. Read and write operations can be carried out.
7. Define ROM
A read only memory is a device that includes both the decoder and the OR gates within a single IC
package.
 8. Define address and word:
 In a ROM, each bit combination of the input variable is called on address. Each bit combination that
comes out of the output lines is called a word.
9. What are the types of ROM.  
1. Masked ROM. 2. Programmable Read only Memory 3. Erasable Programmable Read only memory.
4. Electrically Erasable Programmable Read only Memory.
10. What is programmable logic array? How it differs from ROM?
In some cases the number of don’t care conditions is excessive, it is more economical to use a
second type of LSI component called a PLA. A PLA is similar to a ROM in concept; however it does
not provide full decoding of the variables and does not generates all the minterms as in the ROM.
11.What is mask - programmable?
With a mask programmable PLA, the user must submit a PLA program table to the manufacturer.
12. What is field programmable logic array?
The second type of PLA is called a field programmable logic array. The user by means of certain
recommended procedures can program the EPLA.
 13. List the major differences between PLA and PAL PLA:
Both AND and OR arrays are programmable and Complex Costlier than PAL PAL AND arrays are
programmable OR arrays are fixed Cheaper and Simpler
14. Define PLD.
 Programmable Logic Devices consist of a large array of AND gates and OR gates that Can be
programmed to achieve specific logic functions.

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DE UNIT-5 MEMEORY, PROGRAMMABLE LOGIC DEVICES AND LOGIC FAMILIES- Notes

UNIT-5
MEMEORY, PROGRAMMABLE LOGIC DEVICES AND LOGIC FAMILIES
 Memory is used for storing binary words.

 Reading is the process by which the data can be retrieved from memory:
 Writing is the process by which the data can be stored in the memory.
 Semiconductor memories make use of bipolar and MOS.
 Types of memories -
            (a) RAM
            (b) ROM
 RAM is the random access memory or read/write memory. One can read and write in RAM.
 ROM is the read only memory. One can only read from ROM nothing can be written in it.
 RAM is of two types:
           (a) SRAM
           (b) DRAM

 SRAM is also known as static RAM. In SRAM data will remain stored permanently as long
as power is supplied, they need not required rewriting periodically the data. The basic cell is
SRAM is a flip-flop.
 DRAM is also known as dynamic RAM. In DRAM rewriting periodically the data into
memory is required. The basic cell in DRAM is a capacitor.
 ROM is of four types:
           (a) Masked ROM
           (b) PROM
           (c) EPROM V
           (d) EEPROM V
 In masked ROM the data is stored permanently through photo masking during fabrication i.e.
programming is done through masking and metalization process.
 PROM is the programmable read only memory. it is programmed using PROM-programmer
and once the data is programmed (i.e. written) cannot be rewrite or changed again.
 EPROM is the erasable programmable read only memory. The user can erase and programme
this memory again and again. The EPROM is erased by exposing the chip from inside via
window at the top to ultra violet light.
 EEPROM is the electrically erasable. programmable read only memory. its function is similar
to EPROM but instead UV light the data can be erased using electrical signals.

PLDs (Programmable Logic Devices):

 There are of three types
           (a) PAL
           (b) PLA
           (c) PGA or FPGA.


 PAL are the programmable arary logic in which AND gate arrays are programmable and OR
gate arrays are fixed.
 PLAs are programmable logic arrays in which AND-OR gate arrays are used and
programmed for specific logic functions.
 FPGA is the field programmable gate array. It consists of logic blocks i.e. an array of circuit
elements.

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DE- unit-4 ASYNCHRONOUS SEQUENTIAL CIRCUIT Hand written Notes

 This hand written notes cover the following topics:
Stable Unstable states, Output Specifications, Cycles and Races, Race free assignments,
Reduction of State and Flow tables, Hazards.

To download this hand written notes Click here

DE- Asynchronous Sequential Circuit Lecturing Videos

The video Covers the following topics of unit-4 in Digital Electronics:
Stable Unstable states, Output Specifications, Cycles and Races, Race free assignments,
Reduction of State and Flow tables, Hazards.

Digital Electronics Important Question for IA-2

2 mark :

1.       Define Encoder and decoder with block diagram.

2.       What is priority encoder?

3.       Can a decoder function as a Demultiplexer?

4.       Define Multiplexer and Demultiplexer.

5.       Give other name for Multiplexer and Demultiplexer

6.       Difference between Combinational & Sequential Circuits.

7.       List out the applications of Mux and Demux?

8.       List out the applications of Encoder and Decoder?

9.       What are the applications of seven segment displays?

10.   What is sequential circuit?

11.   List the classifications of sequential circuit.

12.   what is Synchronous sequential circuit?

13.   What is clocked sequential circuits?

14.   What is called latch?

15.   List different types of flip-flops.

16.   What do you mean by triggering of flip-flop.

17.   List different types of triggering in flip-flops.

18.   What is an excitation table?

19.   Give the excitation table of a JK flip-flop

20.   Give the excitation table of a RS flip-flop

21.   Give the excitation table of a D flip-flop

22.   Give the excitation table of a T flip-flop

23.   Give the characteristic equation of a SR, JK, D, T flip-flops.

What is the difference between truth table.


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DE unit-3 Notes

 Combinational circuits and systems produce an output based on input variables only. Sequential circuits use current input variables and previous input variables by storing the information and putting back into the circuit on the next clock (activation) cycle.


A theoretical view of how sequential circuits are made up from combinational logic and some storage elements. There are two types of input to the combinational logic; External inputs which come from outside the circuit design and are not controlled by the circuit; Internal inputs which a function of a previous output states are The internal inputs and outputs are refered to as "secondaries" in the course notes. Secondary inputs are state variables produced by the storage elements, where as secondary outputs are excitations for the storage elements.
Two Main Types of Sequential Circuits
There are two types of sequential circuit, synchronous and asynchronous. Synchronous types use pulsed or level inputs and a clock input to drive the circuit (with restrictions on pulse width and circuit propagation).
Asynchronous sequential circuits do not use a clock signal as synchronous circuits do. Instead the circuit is driven by the pulses of the inputs. You will not need to know anymore about asynchronous circuits for this course.
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Design of Sequential Circuits,Counters & Registers notes - Digital Electronics -Unit-3

A register is a group of binary storage cells capable of holding binary information.
•A group of flip-flops constitutes a register, since each flip-flop can work as a binary cell.
•An n-bit register, has n flip-flops and is capable of holding n-bits of information.
•In addition to flip-flops a register can have a combinational part that performs data-processing tasks.
SHIFT REGISTER
Shift registers are a type of sequential logic circuit, mainly for storage of digital data. They are a group of flip-flops connected in a chain so that the output from one flip-flop becomes the input of the next flip-flop.
Most of the registers possess no characteristic internal sequence of states. All the flip-flops are driven by a common clock, and all are set or reset simultaneously.
The data in a shift register can be shifted in two possible ways: (a) serial shifting and (b) parallel shifting.
The serial shifting method shifts one bit at a time for each clock pulse in a serial manner, beginning with either LSB or MSB.
On the other hand, in parallel shifting operation, all the data (input or output) gets shifted simultaneously during a single clock pulse.
Hence, we may say that parallel shifting operation is much faster than serial shifting operation.
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DE - Unit-3 -SYNCHRONOUS SEQUENTIAL CIRCUITS- 2 Marks Question and answers

1. Difference between Combinational & Sequential Circuits.
2. What are the classifications of sequential circuits?
The sequential circuits are classified on the basis of timing of their signals into
two types. They are:
1) Synchronous sequential circuit.
2) Asynchronous sequential circuit.
3. Define Flip flop.
The basic unit for storage is flip flop. A flip-flop maintains its output state either at 1
or 0 until directed by an input signal to change its state.
4. What are the different types of flip-flop?
There are various types of flip flops. Some of them are mentioned below they are:
1. SR flip-flop
2. D flip-flop
3. JK flip-flop
4. T flip-flop
5. What is the operation of D flip-flop?
In D flip-flop during the occurrence of clock pulse if D=1, the output Q is set and
if D=0, the output is reset.
Set – 1, Reset – 0.
6. What is the operation of JK flip-flop?
1. When K input is low and J input is high the Q output of flip-flop is set.
2. When K input is high and J input is low the Q output of flip-flop is reset.
3. When both the inputs K and J are low the output does not change
4. When both the inputs K and J are high it is possible to set or reset the flip-flop
(ie) the output toggle on the next positive clock edge
7. What is the operation of T flip-flop?
T flip-flop is also known as Toggle flip-flop.
1. When T=0 there is no change in the output.
2. When T=1 the output switch to the complement state (ie) the output toggles.

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Digital Electronics - Unit-1 (Number system & Basic Logic)- Hand Written notes

This material covers the following topics, these are explained briefly with suitable examples.
Make use of it. For more notes you can contact me.

 NUMBER SYSTEM AND BASIC LOGIC
Number systems – Binary, Octal, Hexadecimal, BCD, Excess 3, Complements Conversions and Arithmetic. Boolean theorems, Boolean algebra – AND, OR, NOT, NAND & NOR operation, Sum of Product and Product of Sum forms. Minimization – Kamaugh’s map, Tabular Minimization Procedures.


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Digital Electronics Assignment-1

Digital Electronics

Assignment-I

1.     Perform the subtraction with the decimal numbers given using

         (i) 10’s complement.    (ii) 9’s complement. Check the answer by straight subtraction

         (a) 5249 – 320 (b) 3571 – 2101.

2.     (i) Define Minterm and Maxterm

3.     Simplify the Boolean expression (i)  F = C(B + C)(A + B + C).                             

       (ii)  T=(x + x y z )+ (x + x y z)(x + x y z).

4.     Determine the Binary, Hexa and Octal numbers representation for decimal number 10.625.

5.     (i)Perform the BCD addition: 808 + 229. (ii)Perform the BCD subtraction: 557-399.

6.     (i) Convert the expression into its standard SOP equation. Y = (A + BC) (B + C’ A) (ii) Convert the expression to standard POS equation. Y = (A + B) (A + C) (B + C’)

7.     Simplify the following function in (a) s–o-p and (b) p–o–s by using K-Map. Realize it by using logic gates F(A, B, C, D) = Σ (3, 4, 6, 7, 11, 12, 13, 14, 15)

8.     Simplify it  by using K-Map f( A,B,C,D) = Σ m (0,1,5,7,11,12,13,14,15) and realize using NAND gates.

9.     Simplify it  by using K-Map f( A,B,C,D) = Π M ( 2,3,5,7,10,13,14,15) and realize using NOR gates.

10.  Simplify the Boolean function using tabular method.

                 F(A, B, C, D, E) = Σ (0, 1, 4, 5, 16, 17, 21, 25, 29, 30).

11.  Simplify the Boolean function using tabular method

              F(A, B, C, D, E, F) = Σ (6, 9, 13, 18, 19, 27, 29, 41, 45, 57, 61, 63)

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Notes on Logic Gates

List of Commonly used IC Numbers for Logic gates

IC 7404 – 2 Input -NOT Gate

IC 7432 – 2 Input -OR Gate

IC 7408 - 2 Input -AND Gate

IC7400- 2 Input -NAND Gate

IC7402 - 2 Input -NOR Gate

IC7486 – Quad 2 Input –EX-OR Gate

IC74266 – Quad 2 Input –EX-NOR Gate 

Introduction to Digital Logic Gates :A Digital Logic Gate is an electronic device that makes logical decisions based on the different combinations of digital signals present on its inputs. A digital logic gate may have more than one input but only has one digital output. Standard commercially available digital logic gates are available in two basic families or forms, TTL which stands for Transistor-Transistor Logic such as the 7400 series, and CMOS which stands for Complementary Metal-Oxide-Silicon which is the 4000 series of chips. This notation of TTL or CMOS refers to the logic technology used to manufacture the integrated circuit, (IC) or a "chip" as it is more commonly called.
Classification of Integrated Circuits 

1.     Small Scale Integration or (SSI) - Contain up to 10 transistors or a few gates within a single package such as AND, OR, NOT gates. 

2.     Medium Scale Integration or (MSI) - between 10 and 100 transistors or tens of gates within a single package and perform digital operations such as adders, decoders, counters, flip-flops and multiplexers. 

3.     Large Scale Integration or (LSI) - between 100 and 1,000 transistors or hundreds of gates and perform specific digital operations such as I/O chips, memory, arithmetic and logic units.

4.     Very-Large Scale Integration or (VLSI) - between 1,000 and 10,000 transistors or thousands of gates and perform computational operations such as processors, large memory arrays and programmable logic devices.

5.     Super-Large Scale Integration or (SLSI) - between 10,000 and 100,000 transistors within a single package and perform computational operations such as microprocessor chips, micro-controllers, basic PICs and calculators.

6.     Ultra-Large Scale Integration or (ULSI) - more than 1 million transistors - the big boys that are used in computers CPUs, GPUs, video processors, micro-controllers, FPGAs and complex PICs.

Digital Logic States : The Digital Logic Gate is the basic building block from which all digital electronic circuits and microprocessor based systems are constructed from. Basic digital logic gates perform logical operations of AND, OR and NOT on binary numbers.

In digital logic design only two voltage levels or states are allowed and these states are generally referred to as Logic "1" and Logic "0", High and Low, or True and False. A good example of a digital signal is a simple light as it is either "ON" or "OFF" but not both at the same time.

The Logic "AND" Gate :

A Logic AND Gate is a type of digital logic gate that has an output which is normally at logic level "0" and only goes "HIGH" to a logic level "1" when ALL of its inputs are at logic level "1". The output state of a "Logic AND Gate" only returns "LOW" again when ANY of its inputs are at a logic level "0". In other words for a logic AND gate, any LOW input will give a LOW output.

The logic or Boolean expression given for a logic AND gate is that for Logical Multiplication which is denoted by a single dot or full stop symbol, ( . ) giving us the Boolean expression of:  A.B = Q.

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Digital Electronics 2 mark Question & Answer for Unit-I

1. Define Digital Systems.
A system which processing discrete or digital signal is called as Digital System.

 2. What is meant by bit?
A binary digit is called bit.

3. What is the best example of digital system?
 Digital computer is the best example of a digital system.

 4. Define Radix.
It specifies the number of symbols used for corresponding number system.

5. Define Nibble,Byte and word.
 i). In binary number a group of four bits. ii). A group of 8 bits are called Byte. iii). A group of 16 bits or 4 nibble are called word.

6. List the number systems?
 i) Decimal Number system ii) Binary Number system iii) Octal Number system iv) Hexadecimal Number system
 7. Define binary logic?
Binary logic consists of binary variables and logical operations. The variables are designated by the alphabets such as A, B, C, x, y, z, etc., with each variable having only two distinct values: 1 and 0. There are three basic logic operations: AND, OR, and NOT.


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Digital Principles Switching Theory by A.K. Singh Manish Tiwari Arun Prakash - Fre

      Digital Electronic is intended as a comprehensive text for the courses in digital electronic
circuits. The objective of this book is to develop in the reader the ability to analyze and design
the digital circuits. The increased uses of digital technology in objects used for day-to-day life
necessitate an in-depth knowledge of the subject for the professionals and engineers.
      There are lots of references available on Switching Theory and Basic Digital Circuits,
which discuss various topics separately. But through this text our notion was to discover the
topics rather than to cover them. This comprehensive text fulfills the course requirement on
the subject of digital circuit design for B. Tech degree course in Electronics, Electronics and
Communication, Electronics and Electrical, Electronics and Instrumentation, Electronics
Instrumentation and Control, Instrumentation and Control Engineering of different technical
Universities. This text is also bound to serve as a useful reference book for various competitive
examinations.
      There is no special pre-requisite before starting this book. Each chapter of the book
starts with simple facts and concepts, and traverse through the examples & figures it uncovers
the advanced topics.
      The book starts from chapter 0. It is very obvious because in the world of digital
electronics the very first level is 0 and then comes the last level called 1. This is the reason
why all the chapters of this book have subsections numbered starting from 0.The book has
11 well-organized chapters and 2 appendices.
      Chapter 0 is introduction and is a must for all the beginners as it introduces the concept
of digital signals and digital systems. It attempts to answer why and where the digital circuits
are used what are their advantages. Chapter 1 deals with number systems and their arithmetic.
It includes an exhaustive set of solved examples and exercise to clarify the concepts. Chapter
2 introduces the basic building blocks of digital electronics. It starts with basic postulates,
Boolean algebra and then introduces logic gates. It also deals with several types of types of
implementation using logic gates. For beginners we strongly recommend to work out this
chapter twice before proceeding further.
      Chapter 3 deals with the Boolean function minimization techniques using Postulates and
Boolean Algebra, K-Map and Quine-McCluskey methods. Chapter 4 presents various
combinational logic design using the discrete logic gates and LSI & MSI circuits. This chapter
also deals with hazards and fault detection.
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COMBINATIONAL CIRCUITS unit-2 notes - Part-I

The term “combinational” comes to us from mathematics. In mathematics a combination is an unordered set, which is a formal way to say that nobody cares which order the items came in. Most games work this way, if you rolled dice one at a time and get a 2 followed by a 3 it is the same as if you had rolled a 3 followed by a 2. With combinational logic, the circuit produces the same output regardless of the order the inputs are changed. In general digital circuits are divided into two groups namely
1. Combinational Circuits.
2. Sequential Circuits.
Combinational logic is defined as that class of digital circuits where, at any given time, the state of all outputs depends only upon the values of the inputs at that time and not upon any previous states.

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