Basic Components of a Computer & Its Functions

By Dominic Chooper on March 05, 2022

What are the basic components of a computer and its functions? Generally, the major components of a computer are installed on one single unit or the main board.

A computer is made up of several integrated electronic parts and it is these main components that help them all to operate properly.


Basic Components of a Computer and Its Functions

Basic Components of a Computer and Its Functions

A computer is mainly conceived as an electronic device. It performs different complex functions apart from calculating and processing data such as manipulating them, storing them, and retrieving them as and when required.

However, in order to make all these happen, a computer needs a few additional and basic components that increase its level of performance.

Typically, there are five major computer components as follows:

The operations of these specific computer components can be detailed as follows:

The input devices help in inputting raw data, information, and instructions to the computer that are needed to be processed.

The entire operation during processing of data is carried out and controlled by the CPU or the Central Processing Unit.

This unit ensures that the entire operation is performed in the correct sequence and in the right manner to produce the desired output acceptably.

The result of the processed data is displayed on the output devices such as the computer screen, speakers or printer.

And, for storing the result, there is the primary memory and secondary storage. These also store the data before sending it to the CPU for processing.

Now, at this point, before looking at each of the components of a computer, there is one thing that you will need to keep in mind.

It is that the external appearance of these components and units may be different depending on the different systems but, at the end of the day, they all perform the same tasks.

Now, here are the major components of a computer and their respective and distinctive functions.

Input Devices

There are lots of different input devices that are available out there in the market but you may not need to attach all of them to your computer system.

Depending on your needs you can choose from the following list of input devices.


This is the basic unit without which you cannot go ahead. Usually, you will get keyboards that can be connected to the computer through a USB but there are a few others that can be connected wirelessly via Bluetooth.

There are also different types of keyboards designed according to the region and language. Some of the common types are:


This is another fundamental component of the computer which is hand-held and is used to move the pointer or cursor across the screen.

It has a left and right button as well as a scroll wheel between the two buttons. In the laptops the mouse is replaced by a touchpad.

The most common types of this input device include:


It scans pictures of any text and converts this input into a digital format and displays it on the screen as output by using optical character recognition technique.

Some common types of scanners are:


This is just like a mouse but unless it is upright, the cursor keeps moving in the direction of it. It has a spherical base and a stick which can move freely and control the cursor.

There are different types of joysticks such as finger-operated joysticks, hand operated joysticks, displacement joysticks, isometric joysticks, and more.

Light pen – There is a light-sensitive detector at the tip of this device that looks just like a pen. The tip points to an object, selects it, detects its location, and sends signals to the CPU. It also helps in drawing.


This comes with a stylus and a fat surface usually. The digitizer helps in drawing images just like on a piece of paper using a pencil, and it appears on the screen.

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The software captures and converts the touch inputs into lines, handwritten text and signatures into typewritten words.


A microphone is used to input sound. It captures sound vibrations and changes them into audio signals which are then changed into digital format and stored in the computer.

It also helps in telecommunicating, adding sound to presentations and more. The three most popular types of microphones used are:

Biometric devices

Biometrics devices use the biological features of a person such as face structure, fingerprints, and eye cornea to match it with the stored data in the computer memory and match it to allow access.

Different types of scanners are used for this purpose such as:

Magnetic Ink Character Recognition

Commonly referred to as MICR, it reads printed text with magnetic ink that is sensitive to magnetic field.

Commonly used in banks to process checks, the MICR captures the details and sends it to the computer for processing.

Optical Character Reader

Also called an OCR, it converts scanned images of typed, printed, or handwritten text into digital format.

It is commonly used in libraries and offices to convert books and documents into electronic files.

Digital camera

These cameras come with an image sensor chip that captures images and videos digitally and stores them on the memory card. The photo-sensors in it record the light entering through the lens and return electrical current that creates the images.


This input device is commonly used while playing games. This looks more like a volume knob.

The wheel is held by hand and moved to control the cursor or an object back and forth.

Steering wheel

Commonly used in car racing games, this input device resembles a real steering wheel.

Gesture recognition devices

These devices can recognize gestures and take them as input and interpret them.

Often used in video games, these are also used now in smartphones and tablets.

Light gun

Just as the name indicates, it is used as a gun to shoot targets on the screen while playing a game.

When you pull the trigger the screen goes blank and during this short period the photodiode in the barrel finds out where the gun is pointed.


Commonly found in laptops, these are the alternatives for the mouse and it can do anything that a mouse can.

Touch screen

Used mainly in smartphones and tablets, this technology provides inputs with the touch of a finger.

Virtual Reality

This is a virtual or an artificial environment created by computers where users can interact with different objects.

Some specific types of these input devices include headsets, headphones, gloves and more.


This refers to a camera that is connected to the computer. Sometimes, these are built in the computer, usually at the top of the screen panel.

This input device takes pictures or records videos and stores them in the computer memory to display on the screen when wanted.

Output Devices


The monitor or screen of the computer displays the processed data in the form of text, images, video or audio.

There are different types of monitors available in the market as mentioned below.

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A printer is an output device that produces hard copies of the results of the processed data. It can be text or images on paper.

Depending on the mechanism, there are usually two types of printers namely impact printers and non-impact printers, with different varieties.

Impact Printer

The impact printers use a print head or a hammer that touches the paper while printing the characters or images by pressing the ink ribbon on it. There are two types of impact printers.

Character printer – These printers are not much in use today. However, these printers print one character at a time with one stroke of the hammer. It does not print an entire line at a time. Daisy wheel printers and dot matrix printers are impact character printers.

Line printer – This impact printer comes with a bar and therefore can print one line at a time. It can print about 500 to 3000 lines per minute. Drum printers and chain printers are two examples of line printers.

Non-Impact Printer

The non-impact printers, also known as page printers since they can print one full page at a time, prints without the hammer touching the paper.

The common types of these printers are laser printer and inkjet printer.


This output device enables projecting the image on a large screen or wall.

It is connected to the computer and uses lenses and light to magnify the image so that a large number of people can see it.

Modern projectors are digital and have multiple input sources including HDMI ports and VGA ports, Wi-Fi and Bluetooth.

There are two types of digital projectors.

Liquid Crystal Display or LCD digital projector – This projector is light in weight and most popular.

It uses transmissive technology allowing the light source to pass through three light panels with colored liquid crystal. Some colors pass through and some are blocked by the panels.

Digital Light Processing or DLP digital projector – This projector comes with a series of small mirrors.

There is a separate mirror for every pixel of the image which ensures high quality of the image.

Central Processing Unit

The Central Processing Unit is the brain of the computer and controls every bit of an operation.

It is inserted into the CPU socket or installed on the motherboard. There is a heat sink to suck up and disperse heat to keep the CPU cool.

Ideally, there are three components of a CPU namely:

There are different types of CPU available as well depending on the number of cores present in it such as a single core CPU, a dual core CPU, a quad core CPU or more.


This is a thin circuit board on which almost all internal components of the computer are fixed and distribute power to them to operate.

Motherboards differ in size and type and therefore a specific motherboard is required for a specific type of processor and memory to function properly.

There are different components of a motherboard which include:

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A computer also must have system software to operate. This software actually sets off the hardware and coordinates and controls its functioning.

It also controls the application programs. Some examples of system software are:

In order to perform a few specific tasks, a computer needs application software as well.

Application software can be one program or a set of small programs. The different types of application software are:

Programming software is also needed for a computer to run smoothly especially for the developers when they create debugging and maintenance programs, software or applications.

These are actually facilitator software that helps in translating programming languages such as C++, Java, Python, and others into machine language codes.

These are not used by the end users such as text editors, compilers, debuggers, linkers, interpreters, and others.

Therefore, this type of software is called software development or programming tool. A few examples of these are:

Computer Memory

The computer memory stores data and instructions. These have a large number of small cells or parts with a unique address.

Though there are two types of memory namely the volatile RAM and the non-volatile ROM, depending on their space or location, a computer memory can be classified into four types.

Register memory:

It is the smallest and fastest memory and stores frequently used data and instructions as well as the memory address used by the CPU. Register memory can be of following types:

Cache memory:

This is a high-speed memory and can be accessed by the CPU only. This stores the data and instructions used by the CPU to make them readily available. There are different types of cache memory such as:

Primary memory:

There are two types of primary memory.

Secondary memory:

The secondary memory can be built in or connected to the computer. These are also known as auxiliary storage or external memory and can be accessed indirectly through I/O operations.

This type of memory is non-volatile and therefore stores data and instructions permanently until it is deleted or overwritten.

The CPU cannot access it directly and has to wait till the information is transferred to the primary memory. Some examples of secondary memory are:


There are several components or building blocks of a computer system that makes it function properly and produce the desired results quickly.

Since you use them every day it is very important to know about all of them, which was the primary objective of this article.