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Sunday, 21 October 2012

Laws of Boolean Algebra


Boolean Algebra

The most obvious way to simplify Boolean expressions is to manipulate them in the same way as normal algebraic expressions are manipulated. With regards to logic relations in digital forms, a set of rules for symbolic manipulation is needed in order to solve for the unknowns.

A set of rules formulated by the English mathematician George Boole describe certain propositions whose outcome would be either true or false. With regard to digital logic, these rules are used to describe circuits whose state can be either, 1 (true) or 0 (false). In order to fully understand this, the relation between the AND gate, OR gate and NOT gate operations should be appreciated.


AND Form
OR Form
Identity Law
A ● 1 = A
A + 1 = A
Zero and one Law
A ● 0 = 0
A + 0 = 1
Inverse Law
A ● A’ = 0
A + A’ = 1
Idempotent Law
A ● A = A
A + A = A
Commutative Law
A ● B = B ● A
A + B = B + A
Associate Law
A ● (B ● C) = (A ● B) ● C
A + (B + C) = (A + B) + C
Distributive Law
A + (B ● C) = (A + B) ● (A + C)
A ● (B + C) = (A ● B) + (A ● C)
Absorption Law
A (A + B) = A
A + A ● B = A
A + A’B = A + B
DeMorgan’s Law
(A’ ● B’) = A’ + B’
(A’ + B’) = A’ ● B’
Double Complement Law
X’’ = X
De Morgan’s Law
Tips: Break the line, change the sign


De Morgan’s Law Logic Gates


by: Muhammad Nasruddin Rosli





Muted Professor

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