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Electronics/Basic gates

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Basic Gates

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There are 5 basic gates used in performing logic operations in Digital Electronic namely BUFFER gate, NOT gate, AND gate, OR gate, XOR gate . Each Logic Gate has A Symbol for easy to identify , a Mathematical Expression to identify mathematic logic operation and a Truth Table to completely describe operation of the Logic Gate

Five Basic Logic Gates

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Digital gates Symbol Logic Operation Mathematic Expression
BUFFER Cổng Tiếp (Buffer Gate) Y = BUFFER A Y = A
NOT Y = NOT A Y =
AND Y = A AND B Y = A . B
OR Y = A OR B Y = A + B
XOR Y = A XOR B Y =

The Truth Table of the five basic logic gates above

A B Q = A Q = NOT A Q = A AND B Q = A OR B Q = A XOR B
0 0 0 1 0 0 0
0 1 0 1 0 1 1
1 0 1 0 0 1 1
1 1 1 0 1 1 0

Complement of Basic Logic gates

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Basic Gates Combination Gates Symbol Mathematical Expression
BUFFER Cổng NOT (NOT Gate) Q = is NOT NOT A
Y = A
NOT Cổng NOT (NOT Gate) Cổng NOT (NOT Gate) Y = is NOT A
NAND Cổng NOT (NOT Gate) Q = NOT A AND B
NOR Cổng NOT (NOT Gate) Y = NOT A OR B
XNOR Q = NOT A XOR B

The Truth table of the combination gates above

A B Q = A Q = NOT A Q = A NAND B Q = A NOR B Q = A XNOR B
0 0 0 1 1 1 1
0 1 0 1 1 0 0
1 0 1 0 1 0 0
1 1 1 0 0 0 1

Summary

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Gates Function Symbol
ANSI IEC
Buffer
NOT gate (Inverter)
AND gate
NAND gate (NOT−AND)
OR gate
NOR gate (NOT−OR)
XOR gate (Exclusive-OR)
XNOR gate (NOT−exclusive−OR)
A B Q = A Q = NOT A Q = A AND B Q = A OR B Q = A XOR B Q = A NAND B Q = A NOR B Q = A XNOR B
0 0 0 1 0 0 0 1 1 1
0 1 0 1 0 1 1 1 0 0
1 0 1 0 0 1 1 1 0 0
1 1 1 0 1 1 0 0 0 1