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# Fundamental Logic Gates with Truth Table

## Fundamental Logic Gates with Truth Table:-

A circuit that performs a specific logic operation (AND, OR) is called a logic gate.

Everything in electronics is made up of logic gates. Think of them as the smallest units in the study of electronics. Integrated circuits (ICs) are built of logic gates. These logic gates also form flip-flops, which store data in bytes. Logic gates are made up of transistors, usually MOSFETs (a kind of field-effect transistors). So, transistors make logic gates make flip-flops make registers and other data storage units.

Logic gates take binary inputs and according to their behavior, give out specific binary outputs. There are primarily seven types of gates: AND, OR, NOT, NAND, NOR, XOR, XNOR. NOT takes one input, the rest take two.

AND gives out a high voltage output only when both inputs are high.
OR gives out a high voltage output when at least one input is high.
NOT gives out a high voltage output only when input is low.
NAND gives out a high voltage output only when both inputs are low.
NOR gives out a high voltage output when at least one input is low.
XOR gives out a high voltage output when only one input is high.
XNOR gives out a high voltage output only when both inputs are the same.

To summarise, a logic gate is a bunch of transistors arranged in a specific manner to reproduce the logic operations of boolean algebra in electric circuits using low (ground) and high voltages for 0 and 1.

## THE INVERTER(NOT Gate):-

The invertor or (NOT Gate) is also called inverse Gate. The symbol is shown above the diagram. It has only one input and one output. If the input is one(1) the output is inverse i.e(0) and if the input is zero(0) the output is inverse i.e (1).It is also called a switch gate.

NOT gates are single input device which has an output level that is normally at logic level “1” and goes “LOW” to a logic level “0” when its single input is at logic level “1”, in other words, it “inverts” (complements) its input signal.

The standard NOT gate is given a symbol whose shape is of a triangle pointing to the right with a circle at its end. This circle is known as an “inversion bubble” and is used in NOTNAND and NOR symbols at their output to represent the logical operation of the NOT function. This bubble denotes a signal inversion (complementation) of the signal and can be present on either or both the output and/or the input terminals.

Not Gate

### THE AND GATE:-

An AND gate can have two or it has more than two inputs and performs what is known as multiplication i.e( multiply the inputs). The output of AND gate is high when all inputs are high otherwise all outputs are low. An AND gate produces a HIGH output only when all of the inputs are HIGH. When any of the inputs are zero or low then output is LOW. Therefore, the basic purpose of AND gate is to determine when certain conditions are simultaneously true, as indicated by High levels on all of its inputs, and
produces a High on its output. The logical symbol is shown below.