Input Devices and output devices

Difference between input and output devices

Difference between input and output devices

The main difference between input and output devices is that input devices give instructions to the computer, while output devices produce results provided by the system.

Differences between input and output devices are given below:

1. An input device is a hardware component used to provide instructions, data, or commands to a computer system. Conversely, an Output Device is a hardware component, that is used to present the data to the user which is received from the computer system after processing to carry out a task.

2. Input devices can transfer data to another device but cannot receive data or commands from it. Conversely, output devices can obtain data from another device and produce output from it. However, they cannot transfer data to another device.

3. Input devices can be controlled by the user while output devices are handled by the computer system.

4. Some input devices require complex machine-level coding to provide instructions and data to the computer system, which demands expertise in the field. Conversely, output devices present results in a high-level language that is easily understandable by the user and does not require any effort to interpret the results.

5. Input devices give instructions to the computer system, while output devices present results to the user.

6. Examples of input devices include keyboards, mouse, webcams, pen drives, microphones, joysticks, and so on, while examples of output devices include LCD projection panels, monitors, printers, speakers, and so forth.

Input Devices

Input devices are hardware components that give instructions and data to a computer or electronic device. They act as an interface between the user and the system hardware. Whatever functions a user wants a system to perform, they can give those instructions to the system using input devices.

An input device converts the instructions given by the user into a system-understandable form, such as machine language, low-level language, or binary language, which is understood by the system. Input devices enable users to control the computer device easily. Various types of input devices are used to capture different types of instructions in the form of input, including images, text, sound, and motion.

Types of Input Devices

There are several types of input devices present in the market as a result of advancements in computer technologies. Some common types of input devices include the following:

  1. Keyboard
  2. Mouse
  3. Joystick
  4. Trackball
  5. Touch Screen
  6. Stylus
  7. Scanner
  8. Digitizer
  9. Electric Card Reader
  10. Speech Recognition Devices


The keyboard is the most commonly used input device for providing data to computer systems in the form of text and numbers. The layout of a keyboard is similar to that of a traditional typewriter but the keyboard has some additional keys for performing several other functions. Keyboards are available in various sizes and layouts according to the needs and preferences.

However, traditional keyboards are available in two main sizes 84 keys and 101/102 keys for both Windows and Internet.  Keyboards with  104 keys or 108 keys are also available with additional keys. The availability of different sizes and layouts of keyboards allows users to choose one, whether they want to use it for compactness, gaming, productivity, or multimedia.

Typically, the keyboard is of three types:

  1. QWERTY Keyboard
  2. DVORAK Keyboard
  3. AZERTY Keyboard

Keys on Keyboard:

1. Alphanumeric Keys: These keys include the alphabet keys (A to Z), the number keys (0 to 9) and some special symbol keys.

2. Function Keys: There are 12 function keys on the topmost row of the keyboard from F1 to F12.

3. Cursor Keys (Navigation Keys): These keys, known as the direction keys, are used for navigation and controlling the pointer and screen. These keys come with four directional arrow keys including left (←), right (→), up (↑) and down (↓) keys.

4. Control Keys: These keys also known as modifier keys, include Home, End, Insert, Alternate(Alt), Delete, Control(Ctrl), Windows Key (Win Key) and Escape. These keys modify the function of other keys when together pressed in combination with them. 

5. Special Keys: Enter, Shift, Caps Lock, Number Lock(NumLk), Tab, and Print Screen are some of the special function keys on the keyboard.


The alternative term for a mouse is a pointing device. It was invented by Douglas C. Engelbart in 1963 and has become a widely used input device, particularly for personal computers. While clicking and dragging, it controls and moves a cursor across the screen. The user must physically move the mouse for the cursor on the screen to move; it will not move on its own.

A computer mouse enables users to control the coordinates and movement of the on-screen pointer or cursor by moving the device on a flat surface. It typically consists of a palm-sized box with a spherical ball at its base. As one moves the mouse on a flat surface, the ball detects the mouse’s movement and transmits corresponding signals to the CPU.

In the traditional mouse design, there are two buttons (left and right) positioned on the top of the mouse. Users must click these buttons to select or move items on the screen. Additionally, a wheel, known as the scrolling wheel, is housed between these two buttons. The left mouse button serves to select or move items, while the right mouse button displays additional menus when clicked.

Commonly, the mouse is of four types:

  1. Trackball Mouse
  2. Optical Mouse
  3. Wireless Mouse
  4. Mechanical Mouse


The joystick is another pointing device invented by C.B. Mirick and is used to move and control the cursor around the screen. It is primarily used for computer gaming and computer-aided design (CAD). The joystick derives its name from its use in aviation, where pilots use the control stick to monitor the ailerons and elevators of an aeroplane.

This control stick, a hand-held lever, transmits its pivot coordinates to a computer. A joystick typically includes one or more push buttons that can also be read by computers as desired. Users can move the joystick in all four directions.


The trackball is a special type of mouse invented by Ralph Benjamin, a British Royal Navy officer. While the functions of the trackball are similar to those of a traditional mouse, users do not need to move the entire mouse to navigate the cursor on the screen.

A small, solid ball is placed on top of the mouse or positioned to the left of the centre for navigating the cursor. To use this mouse, users only need to move the ball with their thumbs instead of moving the entire assembly. As a result, the user’s arm and wrist movements are significantly reduced compared to using a traditional mouse.

Touch Screen

A touch screen is a display device that enables users to interact with the digital display of a computer or electronic device. It allows users to perform various actions, such as selecting, inputting commands, typing on a virtual keyboard, drawing, manipulating objects, and navigating menus by physically touching the screen.

It resembles a monitor or TV screen but with touch sensitivity capability. The sensitive panel on the screen recognizes finger touches as inputs. In some devices, beams are used across the touch screen to create a grid, which is interrupted as soon as a finger is brought near the touch screen.

The touch screen system does not require the use of a mouse and keyboard to feed data into the computer. Users can give commands by directly touching the screen’s surface with their fingers or a stylus pen. This device is generally used in public places where only specific information is required by the user. A popular example of a touch screen is an ATM.


A stylus is a small, pen-like drawing device, mainly used with graphic tablets and touchscreen devices. With a stylus, users can easily write and draw on the device screen just like writing or drawing on a paper sheet.

A stylus consists of a pointed tip, often made of rubber or plastic. It is used for writing or drawing, selecting items or navigating menus on the touch-sensitive device screen. It is small in size that it can easily fit in the space provided in its accompanying device. The best example of a device with that stylus is Apple iPhone.


The scanner is used to scan or read images. It scans an image and converts it into a digital format. Its size ranges from small (handheld) to large (flatbed), depending on the need. After scanning, software is required to convert the digital format of the image into a viewable format. Generally, this software is built into the scanner. In the present market, several brands of imaging software are available.

Types of Scanners

Scanners mainly come in two forms:

  1. Image Scanners
    1. Flat Bed Scanners
    2. Hand-Held Scanners
  2. Special Purpose Scanners
    1. OCR
    2. OMR
    3. Bar Code Reader
    4. MICR

 Image Scanners

An image scanner is used to scan pictures and text written on paper. There are various types of scanners, each with its special parts and software used to scan pictures and text and control the scanning process.

The two most common image scanners are:

1) Flatbed Scanner: A flatbed scanner is a type of image scanner commonly used for scanning photographs, documents, and other flat objects. It provides a rectangular flat glass surface to hold a book, a sheet of paper, or other objects for scanning. To scan pictures, the picture needs to be placed on a scanning bed facing down on the glass plate. The scanner captures an image of the document by moving a scanning head along the length of the bed, capturing the entire surface in a single pass. These scanners often come with sheet feeders for scanning multiple sheets of paper rather than one at a time. Most scanners use A4 (8.27×11.69 inches) size paper for scanning images.

2) Handheld Scanners: “Handheld” refers to an object that can be held in the hands. Its size is small, approximately 10cm wide. Additionally, its cost is lower, making it preferable for people who are scanning for the first time. The small size makes it comfortable to carry and store during travel.

Special Purpose Scanners

The special-purpose scanner is similar to an image scanner but with a modified design and software. This modified design enables the special-purpose scanner to perform the following specific operations:

1) Optical Character Recognition (OCR)

OCR is a technique used in scanners to convert optically scanned bitmaps of printed and written text into character codes such as ASCII. For recognizing the characters, it analyzes the text based on light and dark areas. After identifying the characters, it converts them into character codes. Currently, OCR is the best method for digitizing typed pages of text.

2) Optical Mark Recognition (OMR)

The OMR system recognizes the presence of the intended marked field by reflecting light intensity. The pencil mark on a piece of paper reflects less light compared to its surrounding paper. This technique uses a special kind of device, an Optical Mark Reader, for optical reading.

With the help of the OMR system, a huge amount of data can be quickly read, and after reading, the OMR system transfers this data to the computer without the intervention of a keyboard.

3) Bar Code Readers

As the name suggests, they are used to read the text written or printed on products or goods in the form of barcodes or vertical zebra-striped marks.

A barcode reader is a photoelectric scanner similar to a flatbed scanner, comprising a lens, light source, and light sensor for converting optical impulses into electrical pulses.

Barcode readers are mainly used from a market perspective. Every product in the market has a unique product code known as a Universal Product Code (UPC), provided by the companies. When the barcode of a product is scanned with a barcode reader, the details and price of the product are displayed on the connected computer.

4) Magnetic Ink Character Recognition (MICR)

As the name implies, this scanner recognizes magnetic ink characters. This scanning technique is primarily used to verify the correctness and uniqueness of documents such as bank cheques.

Magnetic ink is a special metallic powder (ink) used for printing characters on documents. This ink is sensitive to magnetic fields and the text written with magnetic ink is readable by human beings. MICR is used to read the text and transfer it to the computer system.

MICR scanners are primarily used in banks for reading various details written on bank cheques, such as the cheque number, bank number, branch number, and account number of the customer. Magnetic ink characters are generally printed at the bottom of the cheque.

FAQs about input and output devices

What are 5 input and 5 output devices?

Input devices are used to give commands to the computer system such as keyboards, mouse, microphones, webcams, and scanners.

What are the different types of output devices?
Different Types of Output Devices are Monitors, Printers, Plotter, projectors, CD-ROMs, DVDs,  Headphones, Video cards, Sound cards and more.
What are 5 different input devices?
Commonly used 5 major input devices are a Keyboard, Mouse, joystick, Light Pen, Microphone, Scanner and  Barcode Reader.

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