NOT Gate

AND, OR and NOT agate are the fundamental logic gates in digital electronics system. They are called so because any other gate can be made using these three gates. We have discussed about the OR and AND gate already in our website. Now it is the time to get familiar with NOT gate.

The main concept of NOT gate is easier when compared to the other two gates. NOT gate is often called inverter because it inverts the incoming digital signal. Suppose if the incoming digital signal is 1 then the output signal will be opposite of it i.e. it will be 0, in a similar manner if the incoming signal is 0 then the output signal will be 1.

Symbol of NOT gate

Symbol of NOT gate

Here A is the input signal and output is noted by ‘out’. The above diagram represents the fundamental symbol of NOT gate. The original circuit diagram of this gate consisting various transistors and diodes is not shown here as they will increase the complicacy of the article making it harder for the reader to grasp the basic concept of NOT gate. Now we will look through the truth table of NOT gate.

Truth Table

Suppose A is the input to a NOT gate and B is the concerned output of the gate now we will discuss the different outputs for different inputs. Tabulated form of which is called truth table.

A B
1 0
0 1

From the above truth table it is clear that for input 0 the output will be 1 and for input 1, the output will be 0. So the gate works as an invertors and the name NOT is given due to the fact that this gate gives the opposite signal as the output of its input signal.