Full Adder

Duration: 9 min

This video lesson is available to enrolled students.

Return to /learn/ISRO/digital-electronics/combinational-circuit/adders-subtractors/asset-full-adder after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. General Aptitude & Reasoning: Number System, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Speed Time and Distance, Mixture and Alligation, Data Interpretation, Algebra, Probability, Permutation and Combination, Venn Diagram, HCF LCM, Divisibility Rules, Age Problems, Pipe and Cistern, Partnership, Linear Algebra, Sequence and Series (Series), Statistics, Powers and Exponents (Surds and Indices), Arithmetic, Mensuration and Geometry, Calculus, Trigonometry, Vectors, Speed Mathematics and Basic Mathematics, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analogy, Series (Number and Letter Series) (Numerical Relations and Reasoning), Puzzle Solving (Puzzles), Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Calendar, Seating Arrangements, Coding Decoding, Blood Relations, Directions (Direction Test), Clock, Analytical Reasoning (Counting Figures Reasoning), Ranking, Order and Sequence, Logical Sequence Of Words, Inequality, Data Sufficiency, Cubes & Dices
  3. Computer Networks & Cybersecurity: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware Basics, Network Security
  4. Programming, Data Structures & Algorithms: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  5. AI, Machine Learning, Big Data & Cloud: Emerging Tech Trends, Artificial Intelligence, Big Data Systems, Approaches to AI, Search Algorithms, Knowledge Representation, Cloud Computing
  6. Digital Logic & Computer Organization: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer
  7. TOC & Compiler: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Complexity Theory, Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment
  8. Discrete Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic
  9. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS, Linux OS, Distributed Systems
  10. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Object Oriented Technology, HTML Basics, JavaScript-Basics, Java, XML
  11. Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, Data Warehousing & Mining, Enhanced Data Models, NoSQL
  12. Other Recurring CS Topics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, Multimedia
  13. Live Classes: ISRO Live classes
  14. Full Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video provides a comprehensive lecture on the Full Adder, a fundamental component in digital logic design used for arithmetic operations. It begins by defining the Full Adder as a combinational circuit that sums three input bits: two operands (A and B) and a carry-in (Cin). The instructor explains that An and Bn represent the nth order bits of numbers A and B, while Cin is the carry generated from the addition of the (n-1)th order bits. The lecture progresses to illustrate carry propagation using a 4-bit adder diagram and binary addition examples. Finally, the instructor derives the Boolean logic for the Sum and Carry Out outputs using a truth table and Karnaugh maps, concluding with the implementation of the Full Adder using basic logic gates like XOR, AND, and OR. This structured approach ensures students understand both the theoretical basis and practical circuit design of the Full Adder.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the Full Adder with on-screen text defining it as a 'combinational logic circuit that performs the arithmetic sum of three input bits.' He highlights the inputs An, Bn, and Cin, explaining that An and Bn are nth order bits while Cin is the carry from the (n-1)th order bits. He writes `( ) + ( )` on the board to visualize the addition process and labels the inputs A, B, and Cin. The text on the screen explicitly states 'It consists of three input bits, denoted by A (First operand), B (Second operand), Cin (Represents carry from the previous lower significant position).' The instructor circles the terms An and Bn in the text to emphasize their role as the current bits being added.

  2. 2:00 – 5:00 02:00-05:00

    The lecture transitions to practical examples, showing a 4-bit adder diagram with inputs A3-A0 and B3-B0, and carries C4-C0. The instructor circles specific columns to demonstrate how the carry output from one stage becomes the carry input for the next. He then displays a table of binary addition cases, such as `1+1+1` and `1+0+0`, calculating the results to show how sums and carries are generated in a multi-bit addition scenario. He writes down the binary results, for instance, writing `10` for the sum of `1+1+1` to indicate a sum of 0 and a carry of 1. This section emphasizes the concept of carry propagation where the carry obtained from the addition of two bits is added to the next higher order pair of significant bits.

  3. 5:00 – 8:31 05:00-08:31

    The instructor presents a truth table for the Full Adder with inputs A, B, Cin and outputs Sum, Cout. He uses K-maps to simplify the logic expressions, circling groups of 1s. He derives the Sum expression as `A'B'C + A'BC' + AB'C' + ABC`, which simplifies to `A XOR B XOR C`. For the Carry Out, he derives `AB + AC + BC`. The section concludes with a logic circuit diagram showing the interconnection of XOR, AND, and OR gates to implement the Full Adder. The K-maps are clearly visible with inputs labeled `ab`, `a'b'`, `a'b`, `ab`, `ab'` and `cin`, `cin'`. The final circuit diagram shows the Sum output connected to an XOR gate and the Carry output connected to an OR gate fed by three AND gates.

The video systematically builds the concept of the Full Adder from definition to implementation. It starts with the theoretical definition involving three inputs (A, B, Cin) and explains the role of carry propagation in multi-bit addition. The instructor uses visual aids like a 4-bit adder diagram and binary addition tables to clarify how carries move between bit positions. The core of the lecture involves deriving the logic equations: the Sum is the XOR of all three inputs, and the Carry Out is the majority function (AB + AC + BC). This is achieved through truth table analysis and K-map simplification. The final output is a complete logic circuit diagram, connecting the theoretical Boolean expressions to physical gate implementations, providing a full understanding of the Full Adder's structure and function. The lecture effectively bridges the gap between abstract logic definitions and concrete circuit design, ensuring students can both analyze and construct Full Adder circuits.

Loading lesson…