What is the Purpose of Input Devices in Computers?

In this article, you will understand the purpose of input devices. Also, get to know, the different input devices used in computers.

Their functions and the importance of input devices in a computer.

An input device is a device that sends data to a computer and that allows you to interact and control it.

The keyboards and mouse are the most common or most frequently used devices on a computer.

However, dozens of other devices can also be used to enter data into your computer.

Also Read:- Full form of Computer

What is the purpose of an input device?

The main purpose of an input device in a computer is to provide raw data to the computer to get the desired output.

Input devices are important because they allow you to communicate with a computer and add new information.

For instance, if a computer does not have an input device, it will operate by itself, but its settings, bug fixes, or other user experiences can’t be modified.

You wouldn’t be able to do so without an input device if you wanted to add new data to a computer (e.g. command, document, picture, etc.).

What are the computer Input Devices and their functions?

In terms of computing, an input device is any hardware equipment used to send data to computers thereby facilitating us to interact with it.

It has the capability of converting the raw data into a format or language that is computer-readable and finally delivers the translated data to the Central Processing Unit (CPU) for further processing.

The input devices are categorized based on their mode of input such as Keyboard devices, Point and draw devices, Speech, and recognition devices.

12 Best Examples of Computer Input Devices

The 12 best examples of computer input devices are as follows:-

  • Keyboard
  • Mouse
  • Joy Stick
  • Light pen
  • Graphic Tablet
  • Touch screen
  • Microphone
  • Scanner
  • Magnetic Ink Character Reader(MICR)
  • Optical Character Reader(OCR)
  • Bar Code Reader
  • Webcam

We shall understand each of the listed input devices in brief:-


purpose of input device

It is one of the most commonly used input devices to enter data to the computer by pressing of keys. A keyboard can be connected to a computer either by USB (wired) or Bluetooth (wireless).

As such there are no stated rules for defining the number of keys, but the keyboard of major companies available in the market has 104 keys that include alphabetic characters, numbers, arrows, and a set of function keys.

The difference also lies in its design and construction as some have mechanical keys while some use membrane keys.

The laptop’s keyboard is smaller and lighter than the desktop keyboard as the former is more compact than the latter.

Smartphones and tablets come with an inbuilt visual keyboard on their screen to enter data and commands.

Most of the keyboards in modern times have a QWERTY layout. Previously punch cards and paper tapes were used to transfer data on the computer.

Related Topic:- A-Z Shortcut Keys of Computer



It is the simplest handheld device used to move a cursor or a pointer across the screen.

Earlier the mouse used to have a rollerball integrated beneath the device for movement sensor but the modern mouse comes with optical technology (laser) that controls cursor movements by a visible or invisible light beam.

The mouse is normally used on a flat surface and has two buttons – right and left and a scroll wheel in the center.

The left button is used to select or move the items while the right button is to show the menus. The scroll wheel is used to move the documents and web pages up and down.

Like a keyboard, mice also have either wired or wireless connectivity. The laptop computers come with a touchpad that works as a substitute for a mouse and in smartphones and tablets, the user’s finger works as a mouse.

Track Ball mouse is a still input device having a ball mechanism that can be easily rolled by fingers to move the cursor or pointer on the screen. It is ideal where the desk space is a constraint.



It is a pointing device similar to a mouse. It has a handle with a spherical ball at the upper and lower ends. The lower ball helps in its easy movement.

The movement of the joystick controls the cursor or a pointer on the screen. It can move in all four directions and enables the user to easily control the cursor movement.

Therefore it is used mainly for playing games or computer-aided design.

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

Light Pen

light pen

A light pen is also a pointing device that looks like a pen. It is a light-sensitive device used to draw or write on the screen.

It includes a photocell and an optical system placed inside a small tube.

As soon as the tip of the pen moves on the screen the photocell sensing element of the pen detects the screen location and sends the corresponding signal to the CPU. 

Graphic Tablet

graphic tablet

A graphic tablet also known as a digitizer is an input device that is flat and comes with a pen or stylus.

It converts the hand-drawn work into a digital image.

The user can draw like a pencil with the help of a stylus on the flat surface and the drawing appears on the computer screen.

They also can capture the user’s signature and convert it into a digital format.

Thus it allows converting the drawings or text into a format, suitable for computer processing. 

Touch screen

touch screen

It is nowadays used widely in portable devices such as smartphones, palmtops, tablets, and laptops to interact with the computer with the help of your fingers or stylus.

As the name suggests, it allows users to select, swipe, drag, tap, and do many other options by simply touching them.

Besides this, it is also used in other areas, medical fields, kiosks, ATMs, room automation, and a lot of devices such as cameras, Car GPS, etc. to have a suitably intuitive, rapid, or accurate interaction by the user with the display’s content.

There are two main types of touch screens – Resistive and capacitive touch screens.



It is an input device to transfer sound into the computer.

The analog sound waves are converted into electric signals and are further transformed into digital data and saved in the computer.

The microphones are used for adding sound to the presentation, gaming, chatting, voice recognition, etc.

The different types of microphones are dynamic microphones, condenser microphones, ribbon microphones, etc.



A scanner is an input device that reads an image or character from a hard copy document and converts it into a digital file (pdf). 

Optical character recognition techniques are used in scanners to convert images into digital files.

The digital image can be saved, edited, printed, and also can be shared via email.

There are different types of scanners available in the market such as flatbed scanners, handheld scanners, sheet-fed scanners, drum scanners, photo scanners, etc.

Magnetic Ink Character Reader (MICR)

It is a device that can recognize the characters or details on documents that are printed with a special magnetic ink.

This device is mainly used in banks for the reason that it can process a large number of cheques within minutes with accuracy and is practically tamperproof. 

Optical Character Reader (OCR)

It is a technology capable of reading handwritten or printed text on documents and converting them into digitized text or electronic files (PDFs).

OCR copies the details using a scanner and the inbuilt software converts the document into a two-color black and white bitmap version.

It further differentiates the dark areas as characters and the light areas as background.

Barcode Reader (BR)

bar code reader

It is an automatic input device that uses visible red light to scan or ‘read’ the barcode.

The reflected light is translated into an analog signal that is decoded by the computer to identify the product details from the database.



A webcam is a hardware input device that is either connected to the computer by a USB or inbuilt (in laptops) and is capable of taking still pictures or motion videos of the user or an object in front of it.

The photos taken are of the compact digital type which can be uploaded or used over the internet.

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