A logic gate is a physical device implementing a Boolean function. Logics gates instant decisions depending on the inputs. There are three types of logics AND, OR & NOT and can be expressed in Algebraic form
Now, most of the Logic gates are implemented using MOSFETs (metal–oxide–semiconductor field-effect transistors). But can also be constructed using vacuum tubes, electromagnetic relays (relay logic), fluidic logic, pneumatic logic, optics, molecules, or even mechanical elements.
AND Logic Gate
AND logic gate is similar to an arithmetic multiplication operation, It performs the following operations
Produces a logic HIGH output when both the inputs are HIGH
Produces a logic LOW output when any one input or both the input are LOW
Truth Table
X
Y
X AND Y
0
0
0
0
1
0
1
0
0
1
1
1
Logic diagram
OR Logic Gate
OR gate acts as a selector and it always selects the highest possible output from input
Produces an logic high output when any one input is high
Produces an logic low output when both the inputs are low
Truth Table
X
Y
X OR Y
0
0
0
0
1
1
1
0
1
1
1
1
Logic diagram
NOT Logic Gate
Produces a complement output for the given input
produces a 0 when input is 1 and produces an output 1 when input is 0
Truth Table
X
NOT A
0
1
1
0
Logic diagram
NOR Logic Gate
NOR is a universal gate
Produces an logic HIGH output when both inputs are LOW
Produces an logic LOW output when any one input is HIGH
Truth table and logic diagram
NAND Logic Gate
NAND is a universal gate
Produces an logic HIGH output when any one input is LOW
Produces an logic LOW output when both the inputs are at logic HIGH
XOR Logic Gate
The output is HIGH if either input X or input Y is HIGH
The output is LOW when both are the same.
TRUTH TABLE
Input 1
Input 2
Output
X
Y
Z
0
0
0
0
1
1
1
0
1
1
1
0
Logic diagram
XNOR Logic Gate
If both input X and Y are same then the output is high
