Computer refers to the electronic machine that is capable of following a set
of instructions to produce the desired result as per the given instructions.
It includes many elements like hardware, software, storage, etc. The
components of a computer represent the primary elements necessary for basic
functioning and to make the processing of data easy and convenient.
In this article, we are discussing the primary components of a computer
along with the function of each. The working of each component is also
explained with the help of a structural diagram. While the internal
architectural design may change from one computer to another, the basic
structure remains the same with the same working concept.
What are the main components of the computer?
There are many
parts of a computer
system that help to set up the whole system. When we work on it, it requires
many internal and external devices to perform different tasks. However, when
talking about computer components, a computer system is mainly made up of
three primary components, namely:
• Input Unit
• Central Processing Unit
• Output Unit
All these components participate in almost every task or activity performed
on the computer system. While there are many other essential components, the
above ones are the building blocks of any computer system, which ensure the
smooth functioning of the computer.
Let us understand the function of each component in detail with the
following diagram:
Input Unit
The input unit contains the devices required to input data into a computer
system. Since computers do not react or operate on their own, the input unit
is one of the main components of a computer. This unit establishes a link
between the user and the computer so that the user can direct commands and
data into the computer.
The devices used to input data into the computer are called
input devices. These devices take data from the users and send it to the computer in a
systematic manner for further processing. Like other electronic machines,
the computer system also accepts only raw data (binary data). Input devices
convert the data inputted by the user into binary form for the computer to
understand. Data can be entered or given in the form of text, alphabets,
numbers, symbols, images, etc.
The input unit transmits the data to the computer's primary memory (main
memory), which is then processed by the computer's processor according to
given instructions. The following are some of the commonly used input
devices to perform the activities of an input unit:
• Mouse: The mouse is one of the primary input devices that acts as a
point-and-click device. It enables users to move the cursor and select
specific objects on the computer's screen or monitor. The traditional mouse
usually comes with three buttons, one on the left, one on the right, and one
on the scrolling wheel. It can be connected to the computer both by wire and
wireless.
• Keyboard: The keyboard is another essential input device that consists of several
keys. By pressing the keys, we can enter or input data like letters,
numbers, signs, and other information on the computer. Like a mouse, it can
also be wired and wireless.
• Microphone: Microphone, short for mic, is an optional input device used on computers.
When we need to insert audio into our presentation, do voice conferencing,
recording, broadcasting, or giving voice commands to the computer, etc., we
can connect a mic to the computer.
Microphones come in a variety of shapes and sizes. It enables us to give
voice input to the computer system. The mics are designed to read sounds
from the surroundings and convert this sound (analog waves) into electrical
signals. The signals are further converted into digital forms to be
understood by the computer.
Other examples of
input devices
include a webcam, scanner, touch screen, barcode reader, etc.
Central Processing Unit
The Central Processing Unit (CPU) is an essential electronic hardware
component that controls and processes all functions in a computer system,
including arithmetic and logical operations. All simple to complex
calculations, tasks, or comparisons are performed by the CPU. It takes raw
data from the primary memory, processes it or converts it into meaningful
information desired by the users, and then sends the processed data back to
the primary memory.
The CPU is called the brain of the computer because it controls the
operation of all the parts of the computer. Despite this, the computer's
processor (CPU) also handles the operation of many other units within the
computer system, such as the
control unit, arithmetic logic unit,
and memory unit. The Control Unit (CU) and the Arithmetic Logic Unit (ALU) are commonly
called components of the CPU because they both together make up the
CPU.
Control Unit
Control Unit (CU) is the main unit of the computer system as it controls all
the operations and activities of the computer. It acts as a supervisor and
controls the input/output, memory, and other devices in the computer. It
establishes coordination between all the computer parts and determines the
sequence of process execution for smooth functioning.
It retrieves instructions from the main memory, decodes the instructions,
interprets the instructions, and produces meaningful information. In other
words, the control unit collects the entered data using the input unit,
forwards it for processing, and once it has done so, receives the output and
presents it to the user using the output unit. It can be referred to as the
center of all the processing activities that take place inside a computer
device, making it the backbone of the computer to some extent.
Arithmetic Logic Unit
When mathematical or logical operations are to be performed/processed, the
arithmetic and logic unit comes into play. It handles basic to complex
operations of addition, subtraction, multiplication, and division. Moreover,
it also processes actions such as data comparison and decision making. It
means that this unit helps in performing logical operations like AND, OR,
equal to, less than, and greater than, etc.
Data is transmitted from memory to ALU when needed. After processing is
complete, the information or result is either returned to memory to be
stored permanently, or displayed through an output unit, or for further
processing by the CPU, etc.
Memory Unit
The memory unit is an essential part of a computer system and it is required
by the CPU to store data and instructions. It is used before processing,
after processing as well as during the running of the process to store the
current data. The memory unit is capable of accepting and transferring
data/information to other units of the computer system with the help of the
CPU when needed.
There are mainly two types of memory inside the memory unit, namely primary
memory and secondary memory.
• Primary Memory: Primary memory typically stores input data and immediate calculation
results. It is temporary memory and usually does not store large amounts of
data. Also, it is a volatile memory and the data stored in this memory
remains as long as it is connected to the power supply. Once disconnected
from the power source or the computer is turned off, the data is lost or
erased.
RAM (Random Access Memory) is an
example of primary memory in a computer.
Primary memory uses a set of pre-programmed instructions to forward
processed data (results or information) to other parts of the computer, such
as output unit or secondary memory, etc.
• Secondary Memory: Secondary memory or storage is used to permanently store the processed
data for future use. Once the data is converted into meaningful information,
it can be saved in secondary memory and the used memory can be released to
some extent from the primary memory.
Secondary memory is a non-volatile memory and preserves data even when the
power supply is not connected.
Hard disk drive (HDD) and
Solid State Drive (SSD) are two
popular secondary memory or storage devices used on computers.
Note: Primary memory has very fast read/write access, and thus is
directly accessed by the computer's CPU. Secondary memory cannot be accessed
directly and if data is read/written from/to the secondary memory, the data
is first loaded into the primary memory and then accessed by the CPU for
further processing.
Output Unit
The output unit contains the devices needed to receive and view information
from a computer system. The devices used to receive information or results
from the computer are called
output devices. This unit is an essential component of a computer because without it we
cannot obtain or see information or desired results. Like the input unit,
the output unit also establishes a link between the user and the computer.
As we discussed above, the results obtained after processing are stored in
the primary memory before sending to other units. The output unit retrieves
processed data from the computer's primary memory (main memory), which is
converted into a human-understandable form before being displayed by the
corresponding output device. The following are some of the commonly used
output devices to perform the activities of an output unit:
• Monitor: A monitor, often called a visual display unit, is one of the primary
output devices used on computers these days. It is connected to a computer
to digitally view the output (such as text, images, videos, etc.) on the
screen. The output displayed on the computer's monitor is called soft copy
output. The monitor is typically made of glass, circuitry, adjustment
buttons, power supply, etc., all enclosed within a casing.
• Printer: A printer is another essential output device used with computer systems
these days. Unlike a monitor, a printer helps us to make a hard copy of the
desired output such as a document, picture, or other information on paper.
The printer takes electronic data from the computer and creates an exact
copy of it in monochrome (in this context, black and white) or colors,
depending on the type of printer. Impact and non-impact printers are the two
primary
types of printers.
• Speakers: Speakers are used to receive audio/sound output from the computer system.
They are optional and they can be connected to the computer only when we
need to listen to something like music, movies, dialogues, etc.
Modern computers (especially laptops) come with built-in speakers. However,
we can also connect external speakers using the USB or audio jack port to
get better quality sound output.
Other examples of
output devices
include a projector, plotter, headphones, touchscreen, etc.
Summary
Although a computer system is a combination of several components, the
primary components of a computer are the input unit, central processing
unit, and output unit. All these units work to convert the raw data provided
by the user into meaningful information desired by the user. During the
entire conversion process, the data is stored in the primary memory and
handled by the CPU as per the given instructions.
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