Digital Logic Gates

Logic gates are basic building blocks of an electronic circuit. A logic gate has 2 or more inputs except for the NOT gate in the form of 0 or 1. The entire digital technology of the world depends upon logic gates. All the electronic device be it TV, Mobile, Computers, smartwatch etc are built by digital circuits which in turns are build by logic gates. Basically, we have three kinds of logic gates (ADN, OR, NOT) and others are derived by combining these three logic gates. In this article, we will try to explain each and every logic gates with their logic tables.

Types of logic gates

1. AND

2. OR

3. NOT

4. NAND

5. XOR

6. XNOR

7. NOR

AND gate

An AND gate has two inputs. The output of the gate is fully dependent on the input. In an ADN gate output is true if both the input are true else output will be false. Here true is represented by 1 and false is represented by 0. Logic gate AND explained bellow with truth table and diagram.

Input A	Input B	Output =A • B
0	0	0
0	1	0
1	0	0
1	1	1

OR Gate

Like AND gate OR gate also has two inputs. The output of the gate is fully dependent on the inputs. In an OR gate output is true if any one or both of the input is true else false. Here true is represented by 1 and false is represented by 0. Logic gate OR explained bellow with truth table and diagram.

Input A	Input B	Output =A + B
0	0	0
0	1	1
1	0	1
1	1	1

NOT Gate

Unlike AND and OR gate NOT gate has only one input at a time. The output of the gate is fully dependent on the inputs. In a NOT gate output is just the reverse of the input. It negates the input. Here true is represented by 1 and false is represented by 0. Logic gate NOT explained bellow with truth table and diagram.

Input A	Output =Q
0	1
1	0

NAND gate

NAND gate is the combination of AND gate and NOT gate. NAND gate is also called universal gate of the digital circuit.

Input A	Input B	Output = -(A • B)
0	0	1
0	1	1
1	0	1
1	1	0

XOR Gate or Exclusive OR

XOR also called as Exclusive OR gives true output only when there are odd input means if one input is true then other must be false. In other words, gives true value when the input is 0, 1 or 1, 0.

Input A	Input B	Output = A ⊕ B
0	0	0
0	1	1
1	0	1
1	1	0

XNOR Gate or Exclusive NOR

XNOR is a digital gate which works as a complement of the XOR gate. The output of this gate is just opposite of the XOR gate because of an extra NOT gate which inverts the output.