# Basic Logical gates

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## How do Basic Logical Gates work?

##### 28/08/2018 ## INTRODUCTION

In this project you are going to learn what a logic gate is, how it works and when and why were invented

## HISTORY

Logical gates were created to build the internal circuits of the first computers around the 1940s to perform simple operations such as summing or dividing numbers or other mathematical calculations.

## FUNCTIONING

In digital electronics a logic gate is a circuit that implements (simulating the "mathematical logic”) a particular logic operation of one or more Boolean variables. Based on the number of inputs, which represent the number of variables that a logic gate can receive as input, the logical gates can be classified in:

• two-variable ports: AND, OR, XOR, NOR, NAND and XNOR;
• single variable doors: NOT.

## TRUTH TABLES

Truth tables are a simple method to understand how a logic gate works through the results (output) obtained with different input combinations. Ex: ## TYPES OF GATES

#### AND Gate  AND gate is a logic gate that receives normally two values and returns a positive value only if all input values have a value of 1.

#### OR Gate  OR is a logic gate that receives normally two values in input and returns a positive value if at least one input value has a value of 1.

#### NOT Gate  This logic port inverts the input signal. This logic gate has only one input and one output which will be 1 if the input is 0 or 0 if the input is 1.