Logic Gates | Definitions | Types | Symbols | Truth Tables

Logic Gates-

 

Logic Gates may be defined as-

 

Logic gates are the digital circuits capable of performing a particular logic function by operating on a number of binary inputs. OR Logic gates are the basic building blocks of any digital circuit.

 

Types Of Logic Gates-

 

Logic gates can be broadly classified as-

 

 

In this article, we will discuss about Basic Logic Gates.

 

Basic Logic Gates-

 

Basic Logic Gates are the fundamental logic gates using which universal logic gates and other logic gates are constructed.

 

They have the following properties-

• Basic logic gates are associative in nature.
• Basic logic gates are commutative in nature.

 

There are following three basic logic gates-

1. AND Gate
2. OR Gate
3. NOT Gate

 

1. AND Gate-

 

• The output of AND gate is high (‘1’) if all of its inputs are high (‘1’).
• The output of AND gate is low (‘0’) if any one of its inputs is low (‘0’).

 

Logic Symbol-

 

The logic symbol for AND Gate is as shown below-

 

 

Truth Table-

 

The truth table for AND Gate is as shown below-

 

A	B	Y = A.B
0	0	0
0	1	0
1	0	0
1	1	1

Truth Table

 

Timing Diagram-

 

The timing diagram for AND Gate is as shown below-

 

 

2. OR Gate-

 

• The output of OR gate is high (‘1’) if any one of its inputs is high (‘1’).
• The output of OR gate is low (‘0’) if all of its inputs are low (‘0’).

 

Logic Symbol-

 

The logic symbol for OR Gate is as shown below-

 

 

Truth Table-

 

The truth table for OR Gate is as shown below-

 

A	B	Y = A + B
0	0	0
0	1	1
1	0	1
1	1	1

Truth Table

 

Timing Diagram-

 

The timing diagram for OR Gate is as shown below-

 

 

Also Read- Alternative Logic Gates

 

3. NOT Gate-

 

• The output of NOT gate is high (‘1’) if its input is low (‘0’).
• The output of NOT gate is low (‘0’) if its input is high (‘1’).

 

From here-

• It is clear that NOT gate simply inverts the given input.
• Since NOT gate simply inverts the given input, therefore it is also known as Inverter Gate.

 

Logic Symbol-

 

The logic symbol for NOT Gate is as shown below-

 

 

Truth Table-

 

The truth table for NOT Gate is as shown below-

 

A	Y = A’
0	1
1	0

Truth Table

 

Timing Diagram-

 

The timing diagram for NOT Gate is as shown below-

 

 

To gain better understanding about Logic Gates,

Watch this Video Lecture

 

Next Article- Universal Logic Gates

 

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