Input Devices and Output Devices October 6 University INTRODUCTION TO COMPUTERS Chapter 2 Input Devices and Output Devices Prof. Dr/ Moussa Ibrahim Moussa Dean of Faculty of Information Systems and Computer Science

Learning Objectives Explain the purpose of a computer keyboard and the types of keyboards widely used today. List several different pointing devices and describe their functions.

Describe the purposes of scanners and readers and list some types of scanners and readers in use today. Understand how digital cameras differ from conventional cameras. Explain how audio input is accomplished.

Describe the characteristics of a display device and explain some of the technologies used to display images. List several types of printers and explain their function. Understand which hardware devices are used for audio output.

Overview This chapter covers: Different types of keyboards and pointing devices Types of scanners, readers, and digital cameras and what they are used for Audio input devices

Types of display devices and how they work Types of printers and how they work Audio output

(1) INPUT DEVICES a) Punch Cards Characteristic of punch card:  they are cheaper  they are reliable.

Disadvantage of punch card:  they cannot be reused  the cards have to be handled and stored carefully.  very difficult to rearrange them and to detect there problem  require large storage space since they cannot be folded

b) Keyboard: Advantages of the keyboard :  It is very easy to use a keyboard  It offers a number of facilities  Editing or changing the input data is very easy with the help of the keyboard  It is relatively Inexpensive

c) Mouse: The various types of mouse in use are:  Mechanical mouse  Optical mouse  Opt mechanical mouse

d) Light Pen  The light pen is a picking device  The light pen contains a photocell placed in a small tube  The light pen is especially useful in Computer Aided Design (CAD) applications.

e) Joy Stick:  The position and speed with which the joystick is moved is converted into digital signals  These signals are then sent to the computer system.  The joystick is mainly used in video games applications

f) Track Ball:  The track ball uses a hard sphere to control cursor movement.  The ball can be rotated in any direction by hand and this is translated into a digital signal

g) Touch screen:  A touch panel is a transparent plate which is fitted over the CRT.  Input is registered when a finger or any other object comes in contact with the plate. There are two types of touch panels:  Optical touch panels  Electric touch panels

h) Digitizer : A digitizer converts a graphical or pictorial data into digital form

i) Scanner : Scanner is able to directly enter text and images into the computer memory.

Types of scanners : Optical Scanner: 1. The Optical Mark Reader (OMR) 2. Optical Character Reader b) Magnetic Ink Character Recognition (MICR)

(2) OUTPUT DEVICES a) Printers: Printers are classified as : 1. Impact Printer 2. Non Impact Printer

1. Impact Printer Types of impact printers : - Dot Matrix Printers - Daisy Wheel Printer - Line Printer

Advantages of impact printers:  Their functioning is relatively easy  Multiple copies can be produced at the same time with the help of carbon paper.  Impact printers are noisy in operation and are subject to wear and tear of mechanical parts.

2. Non Impact Printer Ink Jet Printer Laser Printers

b) Plotter : - Drum Plotter - Flat bed i.e. X-Y plotter:

c) Video Display Terminal - CRT

- Flat Panel Display

- The Video Display Terminal The monitor and the keyboard together are called a terminal. The types of terminals are :  Dumb Terminal  Smart Terminal  Intelligent Terminal

 Dumb Terminal

 Smart Terminal

 Intelligent Terminal

d) Computer Output Microfilm (COM): This technology is used to record the computer output as microscopic filmed images.

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