Presented By SHEHAB SHARIER MARINA SULTANA TAMIM TANVIR PROSHANTO PODDER
Objectives Introduction to Boolean algebra. Basic concepts and functions of Boolean algebra. Introduce to Logic gates. Logic circuits and Boolean expressions.
Boolean Algebra An algebra which is use for simplifying the presentation & manipulation of propositional logic. It is also know as Switching Algebra. Invented by George Boole in 1854. Boolean algebra is mainly use for simplify and Manipulate electronic logic circuits in computers .
Basic concepts of Boolean algebra It deals with the binary number system (0,1). The three basic logical operations are: AND OR NOT
AND operation is use for logical multiplication. The dot symbol ( “.” ) used for representing AND operation. AND operator has an output 1 if all the inputs are 1 otherwise the output is . AND Operation Truth Table for logical AND operation. Input Input Output A B C 1 1 1 1 1
OR operation is use for logical addition. The symbol ( “+” ) used for represent OR operation. OR operator has an output 1 if any of the inputs are 1 otherwise the output is . OR Operation Truth Table for logical OR operation. Input Input Output A B C 1 1 1 1 1 1 1
NOT operation is use for complementation. The over bar symbol ( “¯” ) used for represent NOT operation. NOT operator has an output 1 if input is or output if the the input is 1 . NOT Operation Truth Table for logical NOT operation. Input Output A _ A 1 1
Boolean Theorems Basic Theorems :- OR AND NOT A+0=A A.0=0 _ A+A=1 A+1=1 A.1=A _ A . A=0 A+A=A A . A=A _ A+A=1 _ A . A=0 Other Theorems:- A+B=B+A A . B=B . A A+(B+C)=(A+B)+C A+B . C=(A+B).(A+C)
Boolean Function Boolean function is an expression formed with binary variable. It is the combination of Boolean operators such as AND , OR & NOT operators . Input Output X Y X X+Y X.(X+Y) =X.Y 1 1 1 1 1 1 1 1 1 1 1 X.( X+Y)=X.Y Truth table for Boolean function.
Logic Gate Computer carries out all operations by the combination of signals that pass through standard blocks of built-in circuits. Logic gate is an elementary building block of digital electronic circuits that operates one or more input signals to produce standard output. The common use of logic gate elements is to act as switch. In computer logic gates are use to implement Boolean functions.
Type of Logic Gates
AND Gate AND gate is use for logical multiplication input signals. If the input values for an AND gate are 1 then the output is 1 otherwise the output is 0.
OR Gate OR gate performs the logical addition operation. It is an electronic circuit that generates an output signal 1 if any of the input signal is 1.
NOT Gate NOT gate performs the logical complementation operation. It is an electronic circuit that generates the reverse of the input signal as output signal .
Logic Circuits An electronic circuit that is consist with a number of logic gates which is use in computer to perform logical operation on its two or more input signals to produce a combined standard output signal. Logic circuit for Boolean expression Z.(X+Y) X X+Y Y Z.(X+Y) Z Z
Logic circuit for Boolean expression (X.Y.Z).(X+Y+Z) X X X.Y.Z Y X.Y.Z Z (X.Y.Z).(X+Y+Z) X X X+Y+Z Y Z Z
Boolean algebra simplifies logic circuits to increase work efficiency of digital device. Logic circuits can be built for any binary electric or electronic devices including switches, relays, electron tubes and transistors. circuits that perform complex logical functions . A computer can perform its logical functions along with proper execution of other commands. Conclusion