[ AETN1112 ] Boolean Algebra and Logic Gates

Logic 0

This can be: false, off, low, no, and open switch.

Logic 1

This can be: true, on, high, yes, and closed switch.

Truth Table

This describes the relationship between the input and

output of a logic circuit

NOT

Also called as inverter. The simplest digital logic gate with one input and one output that produces the logical opposite (complement) of its input

X = A bar

The Boolean expression for NOT gate

Bubble Symbol

This means inversion. That is, if we have a “1” on one side of the bubble, then we have a “0” on the other side.

OR

A fundamental digital circuit that outputs a high signal (1 or "true") if any of its inputs are high, and a low signal (0 or "false") only when all inputs are low, performing a logical disjunction or Boolean addition (A + B = Q)

X = A + B

The Boolean expression for OR gate

NOR

A digital logic gate that outputs a high signal (1) only when all of its inputs are low (0); otherwise, the output is low (0), essentially inverting the result of an OR gate.

X = A + B bar

The Boolean expression for NOR gate

AND

A fundamental digital logic gate that outputs a high signal (1) only when all of its inputs are high (1); if any input is low (0), the output is low (0)

X = AB

The Boolean expression for AND gate.

NAND

A fundamental digital logic gate that produces a LOW (0) output only when all its inputs are HIGH (1); otherwise, the output is HIGH (1).

X = AB bar

The Boolean expression for NAND

OR

NOT

AND

NOR

NAND

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