Logic Gates
What is logic gates?
Logic gates are electronic devices that perform logical operations on one or more binary inputs (0 or 1)
and produce a single binary output. They are the basic building blocks of digital circuits and are used in
modern electronic devices such as computers, smartphones, and other digital appliances. Logic gates
can perform simple logical operations such as AND, OR, NOT, XOR, and NAND. By combining these gates,
more complex digital circuits can be created, such as adders, multiplexers, decoders, and memory units.
The ability to process and manipulate binary data is essential for modern computing, and logic gates play
a critical role in this process.
Why logic gates are important?
Logic gates are used in the design of digital systems such as microprocessors, microcontrollers, and other
digital integrated circuits. These systems require the use of logic gates to perform various operations,
such as arithmetic and logical operations, memory access, and control of the overall system.
Logic gates are used to design the control unit, which is responsible for managing the flow of data within
a microprocessor. The control unit uses logic gates to decode the instruction set, perform the necessary
operations, and direct data flow to other parts of the system.
In addition, logic gates are used in the design of memory systems, such as RAM and ROM, which are
used for storing data and instructions in a digital system. Logic gates are also used in the design of
input/output (I/O) systems, which are used for interfacing with external devices such as sensors,
displays, and communication interfaces.
We can divide the logic gates into 3 categories:
1. Basic logic gates
2. Universal logic gates
3. Combinational logic gates
Basic gates:
AND, OR, and NOT gates are called basic gates because they are the fundamental building blocks of
digital circuits. These three gates can be combined to create more complex logic circuits that perform
various operations on binary inputs.
AND, OR & NOT GATE-
AND GATE
Truth table of AND gate-
A B Y
0 0 0
1 0 0
0 1 0
1 1 1
OR GATE
Truth table of OR gate-
A B Y
0 0 0
1 0 1
0 1 1
1 1 1
NOT-GATE
Truth table of NOT gate-
A Y
0 1
1 0
NAND GATE
Truth table of NAND gate
A B Y
0 0 1
1 0 1
0 1 1
1 1 0
NOR GATE
Truth table of NOR gate
A B Y
0 0 1
0 1 1
1 0 1
1 1 0
X-OR GATE
Truth table of X-OR gate
A B Y
0 0 0
0 1 1
1 0 1
1 1 0
X-NOR GATE
Truth table of X-NOR gate
A B Y
0 0 1
0 1 0
1 0 0
1 1 1
A Y
0 1
1 0
A B Y Z
0 0 1 0
0 1 1 0
1 0 1 0
1 1 0 1
A B Y1 Y2 Z
0 0 1 1 0
0 1 1 0 1
1 0 0 1 1
1 1 0 0 1
