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Basic Computer Engineering

Lecture 2

Computer Input Output Devices

Input/Output (I/O) Devices

An input/output (I/O) device is any hardware that enables communication between a human operator or other systems and a computer. As the name implies, I/O devices can send data to a computer (output) and receive data from it (input).

Input devices allow users to interact with the computer by providing data or commands. Common examples include keyboards, mice, microphones, webcams, and scanners.

Output devices enable users to see, hear, or otherwise perceive the results of the computer’s processing. Typical output devices include monitors, printers, speakers, and headphones.

I/O devices are vital for the functioning of any computer system, facilitating user interaction and supplying the necessary data for the computer to operate effectively.

Input Devices of Computer

A piece of hardware/equipment that enables the user to enter data into a computer is called an input device. Some of the Commonly used input units used in a computer system are as follows:

  1. Keyboard
  2. Mouse
  3. JoyStick
  4. Light pen
  5. Track Ball
  6. Scanner
  7. Graphic Tablet
  8. Microphone
  9. Magnetic Ink Card Reader (MICR)
  10. Optical Character Reader (OCR)
  11. Barcode Reader
  12. Optical Mark Reader (OMR)

Input Devices Overview

Keyboard

The keyboard is a fundamental and widely used input device that allows users to enter data into a computer. Its layout resembles that of a traditional typewriter, but many manufacturers include extra keys for additional functions. Common keyboard types include those with 84, 101/102, and now even 104 or 108 keys, suitable for Windows and internet use.

Mouse

The mouse is a popular pointing device used for cursor control. Early versions featured a palm-sized design with a rolling ball underneath, while modern mice use sensors to track movement. Basic models typically have two buttons (left and right-click) and a scroll wheel. The mouse facilitates quick cursor navigation but doesn’t directly input text.

Advantages

  • User-friendly
  • Affordable
  • Faster cursor movement compared to keyboard arrow keys

Joystick

Similar to a mouse, a joystick is a pointing device used to control cursor movement on a display. It consists of a stick with a spherical ball at each end, allowing multidirectional movement. Joysticks are commonly used in computer-aided design (CAD) and gaming applications.

Light Pen

A light pen is a digital pointing device that resembles a pen. It allows users to select items on a display or draw directly on the screen. Equipped with a photocell and an optical sensor, it detects its position on the screen and sends signals to the CPU.

Trackball

The trackball is another input device akin to a mouse, especially useful for laptops. It features a ball on top that users can rotate with their fingers to move the cursor. Since the device remains stationary, it requires less space compared to a mouse and comes in various shapes.

Scanner

A scanner functions similarly to a photocopier, converting physical documents into digital format for storage and editing. It captures high-resolution images, transforming them into digital files that can be manipulated on a computer.

Digitizer

A digitizer converts analog signals, such as those from a camera, into digital data. Often referred to as a graphics tablet, it enables precise graphic input and is commonly used for detailed drawing and image applications.

Microphone

A microphone is a common input device that captures sound for digital storage. Microphones are widely used in industries for sound recording, voice calls, video conferencing, and adding audio to presentations.

Magnetic Ink Card Reader (MICR)

MICR devices are commonly found in banks, reading checks printed with magnetic ink. This technology allows for quick and accurate processing of financial documents, significantly reducing errors.

Optical Character Reader (OCR)

OCR devices read printed text by scanning it character by character, converting it into machine-readable code. Unlike scanners, which create images, OCR focuses on text, allowing for easy digital storage and retrieval.

Barcode Readers

Barcode readers scan data in the form of light and dark lines, commonly used for pricing, labeling, and inventory management. They can be handheld or fixed, converting barcode images into alphanumeric values for computer processing.

Optical Mark Readers (OMR)

OMR technology identifies marks made by pen or pencil on specially designed forms, often used for multiple-choice exam answer sheets. It is effective for automating grading processes.

Webcam

A webcam is a camera integrated with a computer, primarily used for video streaming and conferencing. Unlike standalone digital cameras, webcams require a connection to a computer to operate.

Biometric Devices

Biometric devices identify individuals based on unique biological traits, such as fingerprints, facial structure, or iris patterns. Various types of biometric scanners, including fingerprint, retina, and voice scanners, are used for secure identification.

Output Devices

An output device is a piece of hardware that presents the results of processed input. These devices display output in various formats, including images, text, hard copies, and audio/video.

Here are some commonly used output devices in a computer system:

  1. Monitor/Display Screen
  2. Printer
  3. Speakers/Headphones
  4. Projector
  5. Plotter
  6. Braille Reader

Monitors

Monitors, also known as Visual Display Units (VDUs), are the primary output devices for a computer system. They generate images from tiny dots called pixels, arranged in a defined rectangular format. The clarity and sharpness of the image depend on the quantity and size of these pixels.

Printers

Printers are widely used output devices for producing physical copies of information on paper. There are two main types of printers:

  • Impact Printers
  • Non-Impact Printers

Projectors

A projector is an optical output device that takes images from a computer and projects them onto a screen or surface. Older projectors used a light source to shine images through a lens, while modern versions utilize laser technology. Projectors are commonly found in offices, classrooms, auditoriums, and theaters for presentations, videos, and images.

Speakers

Computer speakers are popular output devices that allow users to listen to sound. They receive audio input in either analog or digital form and produce sound as output. With advancements in technology, many speakers now offer wireless and Bluetooth capabilities.

Headphones

Headphones, also known as earphones or headsets, are hardware output devices that can be wired or wireless. They perform the same function as speakers, but the sound is directed to the individual user, making it audible only to them. Headphones come in various shapes and sizes.

Plotters

A plotter is an output device used to create high-quality drawings, designs, and graphics. Unlike standard printers that use dots or pixels, plotters employ one or more pens or markers to draw continuous lines on paper or other materials.

Braille Reader

A Braille reader is designed for individuals with visual impairments, enabling them to access digital information. It converts text into Braille characters that can be read by touch, allowing users to interact with digital content.

Study Material: Basic Computer and Engineering
Unit 1
Lecture 1
Lecture 2
Lecture 3
Lecture 4
Lecture 5
Lecture 6
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