Logic Gates, Definition, Types, Functions, Truth Tables And Boolean Expressions

Logic Gate: A logic gate is a fundamental building block used to perform logical operations on binary data. It is an electronic circuit that takes one or more binary inputs (0 or 1) and produces a binary output based on predefined logic rules. These gates are the building blocks of more complex digital circuits and are used to perform various logical operations, such as AND, OR, NOT, NAND, NOR, XOR, and XNOR.

What is Logic Gate?

Types of Logic Gates

• OR Gate- This gate combines inputs and gives an output of "true" (1) if at least one input is true.
• AND Gate- It also takes inputs and produces "true" (1) only when all inputs are true.
• NOT Gate- This gate inverts the input; if it's "true" (1), the output will be "false" (0), and vice versa.
• XOR Gate- The Exclusive OR gate provides a "true" output when the number of true inputs is odd; otherwise, it gives a "false" output.

• NAND Gate combines AND gate followed by a NOT gate, producing the opposite output of an AND gate.
• NOR Gate- It's an OR gate followed by a NOT gate, giving the opposite output of an OR gate.
• EXOR Gate- It's a combination of an OR gate and an AND gate, providing an output when inputs are different.
• EXNOR Gate- This gate is an inverted version of the EXOR gate, giving an output when inputs are the same.

AND Gate

AND Gate Truthtable

OR Gate

OR Gate Truthtable

NOT Gate

NOT Gate Truthtable

XOR Gate

XOR Gate Truthtable

• If both inputs A and B are 0, the output is 0.
• If input A is 0 and input B is 1 (or vice versa), the output is 1.
• If both inputs A and B are 1, the output is 0.
• Therefore, the XOR gate produces a "true" output (1) when the inputs are different and a "false" output (0) when the inputs are the same.

NAND Gate

NAND Gate Truthtable

• If both inputs A and B are 0, the output is 1 (true).
• If either input A or input B is 1 (or both are 1), the output is 0 (false).
• In summary, the NAND gate gives a "true" output (1) when at least one of the inputs is "false" (0), and it gives a "false" output (0) only when both inputs are "true" (1).

NOR Gate

NOR Gate Truthtable

• If both inputs A and B are 0, the output is 1 (true).
• If input A is 0 and input B is 1 (or vice versa), the output is 0 (false).
• If both inputs A and B are 1, the output is 0 (false).
• In summary, the NOR gate gives a "true" output (1) only when both inputs are "false" (0), and it gives a "false" output (0) for any other combination of inputs.

XNOR Gate

XNOR Gate Truthtable

• If both inputs A and B are 0, the output is 1 (true) since they are the same.
• If input A is 0 and input B is 1 (or vice versa), the output is 0 (false) because they are different.
• If both inputs A and B are 1, the output is 1 (true) again because they are the same.
• In summary, the XNOR gate gives a "true" output (1) when the inputs are the same (either both 0 or both 1), and it gives a "false" output (0) when the inputs are different (one 0 and the other 1).