Boolean Algebra (Operation, Laws, Calculation, Truth Table)
What is Boolean Algebra?
What are the operations of Boolean algebra?
Boolean Operators | Notation | Representation | Definition |
Conjunction | ^ | AND | In this operation, the values are true when both the terms are true otherwise false. It acts as a product of numbers. A.B or A^B |
Disjunction | v | OR | In this operation, the values are false when both the terms are false or otherwise true. It acts as a product of numbers. A+B or AvB |
Negation | ¬ | NOT | It reverts the binary variables such as if true it transposes it to false and if false it converts it to true. |
What is a truth table in Boolean Algebra?
A truth table for conjunction
A | B | A.B or A^B |
1 | 1 | 1 |
1 | 0 | 0 |
0 | 1 | 0 |
0 | 0 | 0 |
A truth table for disjunction
A | B | A+B or AvB |
1 | 1 | 1 |
1 | 0 | 1 |
0 | 1 | 1 |
0 | 0 | 0 |
A truth table for negation
A | ¬A |
1 | 0 |
0 | 1 |
Theorems of Boolean algebra
Theorems | Statement | Expression |
De Morgan’s 1st law | The 1st law of De Morgan states that the complement of the product of the variables is equal to the sum of their individual complements of a variable. | (X.Y)’ = X’+Y’ |
De Morgan’s 2nd law | The 2nd law of De Morgan states that the complement of the sum of variables is equal to the product of their individual complements of a variable. | (X+Y)’ = X’.Y’ |
The truth table of De Morgan’s 1st Law
X | Y | X’ | Y’ | X.Y | (X.Y)’ | X’ + Y’ |
0 | 0 | 1 | 1 | 0 | 1 | 1 |
0 | 1 | 1 | 0 | 0 | 1 | 1 |
1 | 0 | 0 | 1 | 0 | 1 | 1 |
1 | 1 | 0 | 0 | 1 | 0 | 0 |
The truth table of De Morgan’s 2nd Law
X | Y | X’ | Y’ | X + Y | (X + Y)’ | X’ * Y’ |
0 | 0 | 1 | 1 | 0 | 1 | 1 |
0 | 1 | 1 | 0 | 1 | 0 | 0 |
1 | 0 | 0 | 1 | 1 | 0 | 0 |
1 | 1 | 0 | 0 | 1 | 0 | 0 |
Laws of Boolean Algebra
Laws Name | Definition | Expression |
Commutative Law | As a result of commutative law, a logic circuit's output does not change if its variables are changed in sequence. | X * Y = Y * X X + Y = Y + X
|
Associative Law | According to this law, the order in which logic operations are performed has no effect on their effects. | (X * Y) * Z = X *(Y*Z) (X + Y) + Z = X+(Y+Z) |
Distributive Law | This law is used for both addition and multiplication and states that | X* (Y + Z) = (X* Y) + (X* Z) X+ (Y * Z) = (X+ Y) * (X+ Z) |
AND Law | The law that uses the AND operation is said to be the AND law of binary algebra. | X * 0 = 0 X * 1 = X X * X = X X * x̄=0 |
OR Law | The law that uses the OR operation is said to be the OR law of binary algebra. | X + 0 = X X + 1 = 1 X + X = X X +x̄= 1 |
Inversion Law | The inversion law of Boolean algebra states that double inversion of the original variable produces the original variable. | x̄̄ = x |
How to calculate Boolean algebra problems?
Example 1
X | Y | Z | X + Y | X * Z | X + Z | (X + Y) + (X * Z) | (X + Y) + (X * Z) * (X + Z) |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 |
0 | 1 | 0 | 1 | 0 | 0 | 1 | 0 |
0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 |
1 | 0 | 0 | 1 | 0 | 1 | 1 | 1 |
1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 |
1 | 1 | 0 | 1 | 0 | 1 | 1 | 1 |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Example 2
X | Y | Z | X + Y | Y + Z | (X + Y) + Z | X * (Y + Z) | [(X + Y) + Z] + [X * (Y + Z)] |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
0 | 0 | 1 | 0 | 1 | 1 | 0 | 1 |
0 | 1 | 0 | 1 | 1 | 1 | 0 | 1 |
0 | 1 | 1 | 1 | 1 | 1 | 0 | 1 |
1 | 0 | 0 | 1 | 0 | 1 | 0 | 1 |
1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 |
1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |