There are total 7 types of logical gates. They are as below.
1) NOT
It inverts the input. It give logical high output when we give logical low whereas gives logical low as output if we provide logical high as input.
| INPUT | OUTPUT |
|---|---|
| A | NOT A |
| 0 | 1 |
| 1 | 0 |
2) AND
It Gives output as Logically high only when both inputs are at logically high. Otherwise it will give output as logically low.
| INPUT | OUTPUT | |
|---|---|---|
| A | B | A AND B |
| 0 | 0 | 0 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |
3) OR
It gives output as logically low when both inputs are at logically low. Otherwise it will give output as logically high.
| INPUT | OUTPUT | |
|---|---|---|
| A | B | A OR B |
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 1 |
4) NAND
It is the combination of NOT and AND gate. It gives output as logically low when both inputs are at logically high. Otherwise it will give logically high as output.
| INPUT | OUTPUT | |
|---|---|---|
| A | B | A NAND B |
| 0 | 0 | 1 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
5) NOR
It is the combination of NOT and OR gate. It gives output as logically high when both inputs are at logically low. Otherwise it will give logically low as output.
| INPUT | OUTPUT | |
|---|---|---|
| A | B | A NOR B |
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 0 |
6) XOR
It gives output as logically low when both inputs are logically at same level. Otherwise it will give value as logically high.
| INPUT | OUTPUT | |
|---|---|---|
| A | B | A XOR B |
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
7) XNOR
It gives output as logically high when both inputs are logically at same level. Otherwise it will give value as logically low.
| INPUT | OUTPUT | |
|---|---|---|
| A | B | A XNOR B |
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |