Author: M Abo Bakar Aslam

XNOR (Exclusive NOR) Gate

It is invertor of XOR Gate. This gate will generate otput as 1 (HIGH), if number of 1's in inputs are EVEN.

1. Properties

  1. Output will be 1, if number of 1's in inputs are EVEN. Otherwise, output is 0.

2. Symbol - 2 Inputs XNOR Gate

XNOR Gate with 2 Inputs
Figure 1: XNOR Gate with 2 Inputs

3. Boolean Expression - 2 inputs XNOR Gate

Y = (AB′ + A′B)' = (A ⊕ B)'

4. Truth Table - 2 Inputs XNOR Gate

Total Number of Rows = 2^(number of inputs) = 2^2 = 4
Total Numbers: 0, 1, 2, 3
ABY
001
010
100
111

5. Circuit Diagram using Basic Gates

Circuit Diagram for 2 Input XNOR Gate
Figure 2: Circuit Diagram for 2 Input XNOR Gate

6. Symbol - 3 Inputs XNOR Gate

XNOR Gate with 3 Inputs
Figure 3: XNOR Gate with 3 Inputs

7. Boolean Expression - 3 inputs XNOR Gate

Y = (A ⊕ B ⊕ C)' = ((AB′ + A′B) ⊕ C)'
Y = ((AB′ + A′B)'C + (AB′ + A′B)C')'

8. Truth Table - 3 Inputs XNOR Gate

Total Number of Rows = 2^(number of inputs) = 2^3 = 8
Total Numbers: 0, 1, 2, 3, 4, 5, 6, 7
ABCY
0001
0010
0100
0111
1000
1011
1101
1110

9. Circuit Diagram using Basic Gates for 3 Input XNOR Gate

Circuit Diagram for 3 Input XNOR Gate
Figure 4: Circuit Diagram for 3 Input XNOR Gate