## NOT Gate

NOT Gate is a logical gate that gives the LOW output signal when its input signal is HIGH. In other words, the NOT Gate inverts its input signal which is why it is also called Inverter.
The NOT gate has only a single input facility. Let's know NOT Gate Truth Table, Internal Circuit Design, and  Symbol.

### Symbol of NOT Gate:

The symbol of the NOT Gate is triangular in shape and it points to the right side. A circuit is connected to its end. You may notice this circle is also used in NAND and NOR gates. This circle is called the Inversion Bubble.

### The operation of NOT Gate:

The logical gate produces the digital signal according to its inputs. According to the truth table of NOT gate, the operation is,

1. When the input signal is HIGH or '1' or True then the output will be LOW or '0' or False.

2. When the input signal is LOW or '0' or False then the output will be HIGH or '1' or True.

### Truth Table of NOT Gate:

Here 'A' denotes the input of the NOT gate and 'Q' denotes the output.

 INPUT(A) OUTPUT(Q) 0 1 1 0

Boolean Expression of NOT Gate is,

### Circuit Design of NOT Gate using Transistor:

According to the above circuit diagram, when the input is LOW that means there is no supply of the base of the Transistor so the transistor does not conduct current. So the current will flow through the Load and the output will be HIGH.

When the input is HIGH that means the base of the transistor is connected to the supply so the Transistor will conduct the current. The whole current will flow through the transistor because it provides lower resistance than the load. So no current will flow through the load and the output will be LOW.

#### Design of NOT Gate using other Logic Gates:

The logical NOT gate can be designed using NAND Gate or NOR Gate.

By connecting all inputs of the NAND gates together we can make the NOT gate,

By connecting all inputs of the NOR Gates together we can make NOT Gate,

### Example of NOT Gate ICs:

IC7404 is a logic gate IC that consists of six number of NOT gates.
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NOT Gate Truth Table, Internal Circuit Design, Symbol Reviewed by Author on February 21, 2019 Rating: 5