Home / Basic Electronics / Boolean Logic And Basic Logic Gates

Boolean Logic And Basic Logic Gates

What Is Boolean Logic & Basic Logic Gates? Symbols & Truth table.

What Is Boolean Logic?

Boolean logic refers to the form of algebra where the variables have only 2 unique values i.e. TRUE or FALSE. These values are often used as 1 or 0 in binary language.

Boolean function

A Boolean function is a logical operation of one or more than one variables whose resultant is a single binary bit. It can only be either TRUE or FALSE. Boolean functions are based on boolean logic.

Digital Logic Gate

A digital logic gate is a device which implements any Boolean function. Some of these basic logic gates are given below:

 

NOT Gate

NOT gate is a basic digital logic gate. This digital logic gate inverts its input into output. It is also known as Inverter. It is also sometimes referred to as negation buffer. NOT gate is a single input single output gate.

The logical operator for NOT is ‘!’ and it inverts its operand’s value.

The Truth table for NOT gate is:

Input Output
1 0
0 1

AND Gate

This digital logic gate implements the logical AND function, which is the Boolean product of two or more than two variables. AND operation is also known as a logical conjunction. In other words, the output of AND gate is TRUE when all of its inputs are TRUE.

AND function’s operator, the logical conjunction is denoted by ‘Λ’ or ‘.’.

AND gate has minimum two inputs and a single output. The truth table for AND gate is:

Input 1 Input 2 Output
0 0 0
0 1 0
1 0 0
1 1 1

OR Gate:

Digital logic OR Gate implements the logical OR function. Logical OR function gives TRUE output if any of its operands are TRUE. Thus, the output of OR gate is True if any of its Input is TRUE.

OR logic function is also known as inclusive disjunction. And its operator is ‘∨’ or ‘+’.

OR gate has a minimum of two inputs and a single output. The truth table for OR gate is:

Input 1 Input 2 Output
0 0 0
0 1 1
1 0 1
1 1 1

NAND Gate:

NAND Gate is a digital logic gate which performs negative AND function. As its name suggests, NAND (NOT of AND) operation inverts the output of AND operation. In other words, the output of NAND gate is False only when all of its inputs are high.

NAND gate has minimum two inputs and a single output.

NAND gate’s truth table is

Input 1 Input 2 Output
0 0 1
0 1 1
1 0 1
1 1 0

NOR Gate:

The digital NOR gate is a Negative-OR gate. The operation of NOR is negation or NOT of logical OR gate. In other words, the output of NOR gate is LOW when any of its input is HIGH.

It has minimum two inputs and a single output.

The truth table of NOR gate is

Input 1 Input 2 Output
0 0 1
0 1 0
1 0 0
1 1 0

XOR GATE:

Exclusive-OR or XOR gate is a digital gate used as a parity checker. XOR gate gives output TRUE when the numbers of TRUE inputs are odd. For a two-input XOR gate, the output is TRUE if the inputs are different. Otherwise, the gate will produce FALSE output.

The truth table of XOR gate is following

Input 1 Input 2 Output
0 0 0
0 1 1
1 0 1
1 1 0

XNOR GATE:

XNOR gate or Exclusive NOR gate is the negative or inverse of XOR gate. Generally, XNOR gate give output TRUE if it has EVEN number of TRUE inputs. The output of two-input XNOR gate is TRUE if the inputs are same. When the inputs are different, the 2-input XNOR gate produces FALSE output.

The following is the Truth table for XNOR gate

Input 1 Input 2 Output
0 0 1
0 1 0
1 0 0
1 1 1

you may also read:

About Electronic Eng

Check Also

Different Types Of Diodes & Their Applications

Different Types Of Diodes & Their Applications

Various Types Of Diodes With Their Characteristics & Applications The diode is the most used …

Leave a Reply

Your email address will not be published. Required fields are marked *