Logic Gates

Introduction

Logic gates are used to perform logical operations. These operations can be done on single or multiple binary input variables and make a single binary value. In simple relationships, logic gates are the electronic digital circuits that comprise a digital system. Many basic logic gates are used in digital systems to execute commands and operations. The most common are:

• OR gate
• AND gate
• NOT Gate

Furthermore, these gates can be associated in groups of one or two. As a result, we get gates like NAND Gate, NOR Gate, XOR Gate, and XNOR Gate. They are the types of basic logic gates. 

What is basic Logic Gate:

A basic logic gate is an instrument that serves as a foundation for digital circuits. They carry out fundamental logical functions that are essential in digital circuits. Logic gates are found in the majority of electronic devices we use daily. Logic gates, for example, can be found in technology such as smartphones, tablet computers, and memory chips. 

What do basic Logic Gates do?

Basic logic gates in a circuit make choices based on integrating digital signals from input variables. The majority of logic gates have two inputs and one output. Boolean algebra is the foundation of logic gates. The binary output will depend upon the type of logic gate being used and the combined effect of inputs. A logic gate can be compared to a dimmer fixture in that the performance is off in one position – 0, and on in the other – 1. Logic gates are repeatedly detected in integrated circuits (IC). 

Basic logic gates 

AND, OR, XOR, NOT, NAND, NOR, and XNOR are the seven fundamental basic logic gates and are considered the types of basic logic gates. Basic logic gates are said to be used to construct digital systems. The fundamental operations are explained in great detail below using truth tables. 

AND gate:

The AND gate gets its name from the fact that if 0 is considered “false” and 1 is considered “true,” the gate functions similarly to the logical “and” operator. The logic permutations for an AND gate is included in the table below. The input connectors are on the left, and the output connectors are on the right. When both inputs are “true,” the output is “true.” If not, the output is “false.” The output of an AND gate achieves state 1 if and only if all of its inputs are in state 1. AND gate’s boolean expression is Y = A.B. 

OR gate:

The OR gate derives from the fact that it acts similarly to the logical inclusive “or.” If one or both input variables are “true,” the outcome is “true.” Even when both input data are “false,” the outcome will then be “false.” For the outcome to be 1, one or both inputs must be 1. The outcome of an OR gate accomplishes state 1 if one or more of its inputs attain state 1. The OR gate’s boolean expression is Y = A + B, which can be read as Y equals A ‘OR’ B. An OR gate’s truth table is as follows:

XOR (exclusive-OR) :

The XOR (exclusive-OR) gate functions similarly to the rationality “either/or.” Whether either, but just not both, of the input variables are “true,” the outcome is “true.” If both input data are “true,” the outcome is “true.” Alternatively, the outcome is “false.” A further way to understand this circuit is to recognise that when the input data are different, the outcome is 1, but if the input data are the same, the outcome is 0. In an XOR gate, the outcome of a two-input XOR gate acquires state 1 if only one input is decided to add. An XOR gate’s truth table is as follows: 

NOT gate:

A logical inverter, also known as a NOT gate to distinguish from other forms of electronic inverter devices, has a single parameter. It flips the logic state. If the input is 1, the outcome will be 0. If the input is zero, the outcome is one. The outcome of a NOT gate accomplishes state 1 if and only if the input does not achieve state 1. An NOT gate’s truth table is as follows: 

NAND gate:

The NAND gate works by first performing an AND gate and then a NOT gate. It behaves similarly to the logic function “and” accompanied by negation. If both input data are “true,” the outcome is “false.” If not, the outcome is “true.” This fundamental logic gate is a combo of the AND and NOT gates. An NAND gate’s truth table is as follows: 

NOR Gate:

The NOR gate is a combo OR gate followed by an inverter. If both input data are “false,” its outcome is “true.” Otherwise, the outcome is “false.” This gate is a combo of the OR and NOT gates. An NOR gate’s truth table is as follows:

The XNOR (exclusive-NOR) gate:

The XNOR (exclusive-NOR) gate is a combo of an XOR gate and an inverter. If the input data are the same, the outcome is “true,” anything else is “false.” The outcome of an XNOR gate is in state 1 if both of its input data are the same, that is, both 0 or both 1. An XNOR gate’s truth table is as follows: 

Conclusion

We have read about basic logic gates and types of basic logic gates in the above notes. Also, we discussed gate’s truth for the types of basic logic gates for more clarity.

Combinations of the logic gates could be used to perform complicated tasks. In theory, the number of gates assembled together in a single device is unlimited. However, there is a physical edge to the gates number that can be loaded into a provided physical space. Digital integrated circuits comprise arrays of logic gates. As Circuit technology progresses, the physical range for each independent logic gate tends to decrease, and digital devices of the same or smaller size get to be qualified to perform increasingly complicated operations at increasing speeds.