XOR Gate Truth Table, IC No, And VHDL Code

Introduction

XOR gate and XNOR gate are logical gates which performs logical XOR operation and XNOR operation respectively on inputs. The XOR gate truth table & XNOR gate truth table consists of the combination of inputs and its outputs. These gates use to implement the Boolean function.

In this article we will discuss about XOR gate truth table, XNOR gate truth table, its operation, Boolean equation, graphical symbol, XOR gate IC number, XNOR gate IC number and many more aspects of these gates.

XOR Gate

XOR Gate Operation Or Working

 The XOR gate have two or more inputs and a single output. Inputs are on the left, and the output is on the right in graphical symbol.

The output of XOR gate is HIGH or 1, when

  • A is LOW and B is HIGH or
  • A is HIGH and B is LOW.

. The output of XOR gate is LOW or 0, when

  • both A and B is LOW or
  • both A and B is HIGH.
XOR Gate Boolean Expression

If A and B are two inputs and Y be output then its equation is given by

Y = AB’ + A’B where A’ represent NOT of A and B’ represent NOT of B.

Y = A XOR B

XOR Gate Truth Table
xor gate truth table
XOR Gate truth table image

The above XOR Gate truth table consist the two inputs A and B and one Output Y.

For two inputs there are four combination in XOR gate truth table:

  1. When inputs A = 0 and B= 0, then A XOR B = Y = 0. That is Y is LOW. Since we know whenever both A and B is LOW or 0 then its output is also LOW or 0.
  2. When inputs A = 0 and B= 1, then A.B = Y = 1. That is Y is HIGH. Since we know whenever A is LOW or 0 and B is HIGH or 1 then its output is HIGH or 1.
  3. When inputs A = 1 and B= 0, then A.B = Y = 1. That is Y is HIGH. Since we know whenever A is HIGH or 1 and B is LOW or 0 then its output is HIGH or 1.
  4. When inputs A = 1 and B= 1, then A.B = Y = 0. That is Y is LOW. Since we know the output of XOR gate is LOW or 0 when all of its input are HIGH or 1.
XOR Gate IC Number
xor gate truth table
XOR Gate IC Diagram

For two input and gate,

  • the IC uses is IC 7486.
  • This IC comes in 14 pin DIP Package.
  • It consist of four 2 input XOR Gate in single IC.
XOR Gate VHDL Code

The vhdl code for two input XOR gate is given below:

We can verify the operation using XOR gate truth table.

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity xor_g is
    Port ( INA : in  STD_LOGIC;    -- input
           INB : in  STD_LOGIC;    -- input
           OY   : out STD_LOGIC;   -- output
end xor_g;

architecture Behavioral of xor_g is
begin
    OY <= INA xor INB;    -- 2 input XOR gate
end Behavioral;

XNOR Gate

XNOR Gate Operation or Working

XNOR gate is also known as exclusive NOR gate. It reduce the boolean expression and number of AND, OR & NOT gates in the circuit.

The XNOR gate have two or more inputs and a single output. Inputs are on the left, and the output is on the right in XNOR gate symbol.

The output of XNOR gate is HIGH or 1, when

  1. The input combination have even number of logic 1 or
  2. The input combination have all logic 0

. Otherwise the output of XNOR gate is LOW or 0.

XOR Gate Boolean Expression

If A and B are two inputs and Y be output then its equation is given by

Y = (AB’ + A’B)’

                                   where A’ represent NOT of A and B’ represent NOT of B.

Y = NOT ( A XOR B )

Y = A XNOR B

XNOR Gate Truth Table For 2 Inputs Gate
XNOR Gate Truth Table
XNOR Gate Truth Table

the above XNOR Gate truth table consist of two inputs A and B, and one Output Y.

For two inputs there are four combinations in XNOR gate truth table:

  • When inputs A = 0 and B= 0, then A XNOR B = Y = 1. That is Y is HIGH. Since we know whenever the input combinations have all logic 0 then its output is HIGH or 1.
  • When inputs A = 0 and B= 1, then A.B = Y = 0. That is Y is LOW. Since it does not have  input combination of even number of logic 1 or the input combination of all logic 0.
  • When inputs A = 1 and B= 0, then A.B = Y = 0. That is Y is LOW. Since it does not have  input combination of even number of logic 1 or the input combination of all logic 0.
  • When inputs A = 1 and B= 1, then A.B = Y = 1. That is Y is HIGH. Since we know whenever the input combinations have even number of logic 1 then its output is HIGH or 1.
XNOR Gate IC
XNOR Gate Truth Table
XNOR Gate IC pin diagram

For two input gate,

  • the IC uses is IC 74266.
  • This IC comes in 14 pin DIP Package.

It consist of four 2 input XNOR Gate in single IC.

XNOR Gate VHDL Code

The VHDL code for two input XNOR gate is given below:

We can verify the operation using XNOR gate truth table.

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
entity xnor_g is
    Port ( INA : in  STD_LOGIC;    -- input
           INB : in  STD_LOGIC;    -- input
           OY   : out STD_LOGIC;   -- output
end xnor_g;
architecture Behavioral of xnor_g is
begin
    OY <= INA xnor INB;    -- 2 input XNOR gate
end Behavioral;

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