Logic Gates

In electronics, Logic gates are the building blocks of every electronic circuit. Logic gates defined as the simple electronic circuits having one or more input and a single output. Their operation varies from one type of logic gate to another. The relationship between input and output follow a certain logical equation.

What is Logic Gates?

Logic gate can be defined as a simple boolean function, which means that it has only either of two outputs. Either 1 or 0, high or low, true or false, whatever you can call it. It is the most elementary tool in building a circuit. A logic gate performs a logical operation on input and gives the appropriate output for it.

NOT GATE
This function will have a single input only. It is also called an inverter as it gives the reverse of the input function.

Types of Logic Gates

A logic gate is a basic building block of an electronic circuit, especially digital circuit, which is used to implement a Boolean function. Given below are the different types of logic gates, their symbols, descriptions and truth tables.

AND GATE

If ‘0′ is false and ‘1′ is true, then the gate acts as the logical “and” operator. The output will be 1 only if ‘all’ inputs are true. It can have more than 1 input.

X Y Z
0 1 0
1 0 0
0 0 0
1 1 1

NAND GATE

It is the NOT AND gate. The inverter bubble reverses the output of the AND gate logic, giving a 0 output only when all inputs are 1.

NAND Gate

OR GATE

If “anyone” of the inputs is 1, the output is 1. The output is 0 only if all inputs are 0. It can have more than 1 input.

OR gate

NOR GATE

It is the NOT – OR gate. The inverter bubble reverses the output of the OR gate logic giving 1 as the output only if all inputs are 0. It can have more than 1 input. The circuit diagram and truth table is given below

 NOR gate

XOR GATE

It is the ‘Exclusive – OR’ gate. The output is 1 only when one of the inputs is 1. And 0 if the inputs are the same.

 XOR Gate

XNOR GATE

It is the ‘Exclusive – NOR’ gate is a combination of XOR gate followed by an inverter. The output is 1 only when both the inputs (even high) are the same and false if the inputs are different.

XNOR Gate

Universal Logic Gates:

A universal logic gate is one which can implement any Boolean function {0,1}, without the use of any other logic gate. Simply put, a logic gate which can serve the function of ALL other logic gates, including itself. The NAND and NOR gates are called universal logic gates because all the other gates can be created using these two.

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Logical Gate Formulas

Following is the table explaining the logical gate formulas:

Logical gate Boolean notation
AND X.Y
NAND \(\bar{X.Y}\)
OR X+Y
NOR \(\bar{X+Y}\)
XOR \(X\bigoplus Y\)
XNOR \(\bar{X\bigoplus Y}\)

Logic Gates Questions (FAQs):

Q1: Explain Logic gate?

Ans: Logic gate definition is given as “Simple electric circuit which has one or more than one input and one output. Here input to output relationship is based on boolean function, which means that it has only either of two outputs”.

Q2: What are the types of logic gates?

Ans: The types of logic gates are AND gate, OR gate, NOT gate, NOR gate, NAND gate, XOR gate, NXOR gate.

Q3: Explain universal logic gate?

Ans: the A universal logic gate is one which can implement any Boolean function {0,1}, without the use of any other logic gate.

Q4: Why the NAND and NOR gates are called universal logic gates?

Ans: because all the other gates can be created using the combination of these two.

Q5: If the inputs (0,1) are fed into AND gate, What will be the output?

Ans: If the inputs (0,1) are fed into AND gate, the output will be 0.

Q6: If the inputs (0,1) are fed into OR gate, What will be the output?

Ans: If the inputs (0,1) are fed into the OR gate, the output will be 1.

Q7: If the inputs (0,1) are fed into NAND gate, What will be the output?

Ans: If the inputs (0,1) are fed into NAND gate, the output will be 1.

Q8: If the inputs (0,1) are fed into NOR gate, What will be the output?

Ans: If the inputs (0,1) are fed into NOR gate, the output will be 0.

Q9: If the inputs (0,1) are fed into XOR gate, What will be the output?

Ans: If the inputs (0,1) are fed into XOR gate, the output will be 1.

Q10: If the inputs (0,1) are fed into NXOR gate, What will be the output?

Ans: If the inputs (0,1) are fed into NXOR gate, the output will be 0.

Hope you have understood about logic gates, logic gate definition, Types, Formula, Input and Output table, etc and able to answer the questions like what is logic gates? what are its types? Corresponding truth table and circuit symbols. to learn more about logic gates, integrated circuit, and many other topics keep reading related links mentioned below.

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