LOGIC GATES Identification and application

Logic gates power point presentation

1. REPESENTED BY KHUSHI KAUSHAL GIRI MONIKA SHEORAN MANISH VAISHNAV LOGIC GATES REPREESNTED TO Mr.AMIT SIR

2. What is a logic gate ? Logic gates are the building blocks of digital circuits that makes use of diodes and transistors to perform switching function . It is used for performing a particular logical operation . A gate is a digital circuit that follows certain logical relationship between the input and output voltages. A logic gate has one output but one or more inputs . There are three basic gates named as OR gate, AND gate, and NOT gate. Each basic logic gate is indicated by a logic symbol and its function is defined and described either by a truth table or by a Boolean expression.

3. Boolean expression Boolean algebra is a different kind of algebra in which only two states of variables [0 and 1] called Boolean variables are allowed . Hence , to describe the functioning of a logic gate in terms of an equation , we use Boolean expression . It is defined as the expression showing the combination of two Boolean variables resulting into a new Boolean variable known as Boolean expression.

4. Some postulates and laws of Boolean algebra Boolean postulates 0 + A = A 1 + A = 1 0 X A = 0 1 X A = A A + A = 1

5. Identity law A + A = A A X A = A Negative law A = A

6. OR gate An OR gate has two or more inputs and one output . If any of the inputs are 1 then output is 1. Boolean expression : Y = A + B Logic symbol :

7. Truth table

8. AND gate It has two or more inputs and one output . Output is 1 only when all the inputs are 1 Boolean expression : Y = A X B Logic symbol :

9. Truth table

10. NOT gate It has only one input and one output . It gives an inverted version of its input , i.e. if input is 1 then output is 0 and vice versa . Boolean expression : Y = A Logic symbol :

11. Truth table

12. Combination of logic gates Various combinations of three basic gates give rise to complicated digital circuits. 1. NAND gate It has two or more inputs and one output . It is a combination of AND and NOT gate . In this gate if all the inputs are 1 then output will be 0. Boolean expression : Y = A B Logic symbol :

13. Truth table :

14. 2 NOR gate It has two or more inputs and one output . It is a combination of OR and NOT gate. If all the inputs are 0 then only output will be 1 otherwise it is 0. Boolean expression : Y = A + B Logic symbol :

15. Truth table :

16. Ex-OR gate It is also called the exclusive OR function . It is a function of two logical variables . If one of the two variables is 0 and the other is one the output will be 1. The output will be 0 if both the variables are 0 or 1. Boolean expression : Y = AB + AB Logic symbol :

17. Truth table :

18. Ex-NOR gate It is also called exclusive NOR function . It is a function of two logical variables. If one of the two variables is 0 and the other is 1 The function is 1 if both the variables are 0 or 1. Boolean expression : Y = AB + AB Logic symbol :

19. Truth table :

20. Applications of logic gate Logic gates are fundamental components in digital electronics, performing essential logical operations. They are used in various digital devices and systems, including computers, microprocessors, and smartphone OR Gate Applications The OR gate has multiple applications: Alarms : Used in fire alarms, where the OR gate triggers the alarm if any sensor detects smoke

21. Voting Systems : Utilized in simple voting systems where a high signal represents a positive response Multiplexers (MUX) : OR gates are used in designing multiplexers, which take multiple inputs and provide a single output Arithmetic Logic Units (ALUs) : Employed in ALUs for binary addition and other digital operations. Memory Devices : OR gates help decode specific addresses and regulate read/write operations

22. AND Gate Applications The AND gate is crucial in various sectors: Digital Circuits : Used in designing combinational circuits like multiplexers, decoders, and controllers. Decision-Making Devices : Employed in systems where multiple conditions must be met, such as interlocking systems. CPUs : Integral in CPUs for satisfying multiple conditions and isolating specific bits. Binary Multipliers : Used in binary multipliers and designing half-adders and full-adders

23. NOT Gate Applications The NOT gate, also known as an inverter, has several applications: Basic Inversion Operations : Used to implement basic inversion operations. Complex Gates : Combined with AND or OR gates to create more complex gates like NAND and NOR. Memory Blocks : Used in designing flip-flops, latches, RAM, and registers in processors

24. NAND Gate Applications The NAND gate, another universal gate, is widely used: Universal Gate : Can independently implement any Boolean function. Inverter : Works as an inverter like the AND gate. Combinational Logic Circuits : Used in developing combinational logic circuits. Sequential Logic Circuits : Employed in creating sequential logic circuits like SR latches or flip-flops.

25. NOR Gate Applications The NOR gate, a universal gate, has diverse applications: Universal Gate : Can create any other logic gate. Inverter : Functions as an inverter like the NOT gate. Combinational Logic Circuits : Used in developing combinational logic circuits. Sequential Logic Circuits : Employed in creating sequential logic circuits

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