Definitions [3]
Definition: Logic Gate
A device that acts as a building block for digital circuits and performs basic logical functions that are fundamental to digital circuits is called a Logic Gate.
Definition: Analog Signal
A signal that has continuous values is called an Analog Signal.
Definition: Digital Signal
A signal that has only two states (0 and 1) is called a Digital Signal.
Formulae [1]
Formula: Logic Gates
| AND Gate | Y = A ⋅ B |
| OR Gate | Y = A + B |
| NOT Gate | Y = \[\overline A\] |
| NAND Gate | Y = \[\overline {AB}\] |
| NOR Gate | Y= \[\overline {(A+B)}\] |
| X-OR Gate | Y = A ⊕ B = \[\overline A\] ⋅ B + \[\overline {AB}\] |
Key Points
Key Points: Logic Gates
| OR GATE | NOT GATE | AND GATE | NOR GATE | NAND GATE |
|---|---|---|---|---|
 |
 |
 |
 |
 |
| 2 inputs, 1 output | 1 input, 1 output | 2 inputs, 1 output | 2 inputs, 1 output | 2 inputs, 1 output |
| Y = A + B | Y = Ā | Y = A·B | Y = (A + B)̅ | Y = (A·B)̅ |
| If any input is high, output is high | Inverted input is produced | If any input is low, output is low | When both inputs are low, output is high | When both inputs are high, output is low |
