External Devices

1. S. M. Shariful Saber
Student’s ID: 11102930
Session: 2010-11
Electrical and Electronic Engg.
Jatiya Kabi Kazi Nazrul Islam University
Trishal, Mymensingh, Bangladesh
Prepared By:

2. External Devices
(Peripheral Device)
My Presentation Topics:

3. Overview of Presentation:
 Definition of External device
 Classification of External device
 Some Input device
 Some Output device
 Some Storage device

4. Definition of External Device
 An external device is a device that it provides a means of
exchanging data between the external environment and the
computer.
 An external device attaches to the computer by a link to an I/O
module .
 The link is used to exchange control, status and data.
 An external device is also referred as a Peripheral device or
simply Peripheral .

5. External Device
 The interface to the I/O module is in form
of control , data and status signals.
 Control signals determine the function
that the device will perform, such as send
data(INPUT / READ), accept data(OUTPUT
/ WRITE) etc.
 Data are in the form of a set of bits.
 Status signals indicate the state of the
device, such as READY/NOT-READY .
 Control logic controls the device’s
opertation.
 Transducer converts data from electrical
to other from and vice versa.
 Buffer holds the data temporarily.
Figure: Block Diagram of an External Device

6. Classification of External Device
 There are many different external devices, but they fall into three general
categories:
 Input devices, such as a keyboard and a mouse
 Output devices, such as a monitor and a printer
 Storage devices, such as a hard drive or flash drive

7. Input Devices
 In computing, an input device is a external device (piece of
computer hardware equipment) used to provide data and
control signals to a computer.
 There are many types of input devices, such as
 Keyboard
 Mouse
 Scanner
 Microphone
 Joystick ,etc

8. Input devices
 Most common input device used with
computer.
 Keyboards allow to input letter, numbers
and other symbols into a computer.
 It has some major types of key, such as
control keys, function keys,
alphanumeric keys, numeric keys
 Each character is associated with a 7 or 8
bit code.
 Keyboard connects to the computer
using either USB or Bluetooth for
wireless communication.
Keyboard
Figure : Typical Keyboard

9. Input Devices
Mouse
 A computer mouse is a pointing
device (hand control) that
detects two-dimensional motion.
 Physically, a mouse consists of an
object held in one's hand, with one or
more buttons.
 There are many types of mouse, such
as Wireless, Gstick, Optical, Trackball,
Mechanical etc.
Figure : Typical Mouse

10. Output Device
 An output device is any device used to send data from a computer to
another device or user. Most computer data output that is meant for
humans is in the form of audio or video.
 There are many types of output devices, such as
 Monitor
 Printer
 Projector
 Speaker etc.

11. Output Device
 The most common output device in
computer .
 It converts the electrical signal to
character or other form.
 It allows the user to interact with the
computer, typically using the
keyboard and mouse.
Monitor
Figure : Monitor

12. Output device
 A printer is a peripheral which makes a
human-readable representation of
graphics or text on paper or similar
physical media.
 It can print documents stored on
memory cards or from digital
cameras and scanners.
Printer
Figure : Printer

13. Storage Device
 A storage device is any computing hardware that is used for storing and
extracting data files and objects. It can hold and store information both
temporarily and permanently, and can be internal or external to a
computer.
 Some storage device are
 Hard Drive
 Floppy disk
 Memory card
 USB flash drive etc.

14. Storage Device
 Hard disk is also known as HDD
(abbreviation), hard drive, disk drive,
fixed drive, fixed disk, fixed disk drive.
 data storage device that uses magnetic
storage to store and
retrieve digital information
 The operating system, software and
most other files are stored in the hard
disk drive.
 The hard drive is sometimes referred to
as the "C drive"
Hard Disk
Figure : Hard disk or Disk drive

15. Thanks to ALL