An input device allows a user to enter data and instructions into a computer. Common input devices include keyboards, mice, microphones, scanners, digital cameras, and webcams. Keyboards contain typing keys, function keys, and control keys to control the cursor. Mice contain buttons to select objects and scrolling wheels. Scanners are used to input photos and text into digital formats.

1. Input Devices
• An input device is any hardware component
that allows you to enter data and instructions
onto a computer. Six Widely used input
devices are the keyboard, mouse,
microphone, scanner, digital camera and PC
video camera.

2. The most common input devices are
following.
1. Keyboard
2. Mouse
3. Scanner
4. Joystick
5. Trackball
6. Sound recorder

3. A keyboard is a series of switches connected to a
microprocessor that monitors the state of each switch and initiates
a specific response to a change in that state.

4. Types of Keyboards
• 101-key Enhanced keyboard
• 104-key Windows keyboard
• 82-key Apple standard keyboard
• 108-key Apple Extended keyboard

5. Types of Keys
• Typing keys
• Numeric keypad
• Function keys
• Control keys

6. F1: Opens the help page of the working program.
F2: Renames a highlighted icon or file. Alt + Ctrl + F2 and Ctrl + F2 give some
more functions.
F3: Search feature for many programs including web browsers.
F4: Repeats last action performed while typing in Microsoft Word. Alt + F4 key
closes all active windows. Ctrl + F4 closes the front most window.
F5: Refreshes (updates) pages in web browsers and other applications.
F6: Moves cursor to writing web address at the address bar.
F7: Normally opens a “spell checker” but this key can be reassigned, depending
on configurations and software.

7. F8: It can perform several functions, and does not have an assigned Windows
default. However, when starting Windows 2000 or Windows XP, holding the
F8 key will boot in Safe Mode.
F9: Boot Option in Booting time
F10: Activates the menu bar in many programs. Shift + F10 + mouse can be used
for an external function.
F11: Sets to full screen on most of the programs.
F12: In Microsoft Word, this key can be used for saving documents, and also
opens up developer tools window in most of the browsers, and, on most of
the newer computers that allow PXE Boot, this button allows users to boot
from the network.

8. Control keys provided cursor and screen control. Four
keys arranged in an inverted T formation between the typing
keys and numeric keypad allow the user to move the cursor
on the display in small increments. The control keys allow the
user to make large jumps in most applications.
Common control keys include:
• Home
• End
• Insert
• Delete
• Page UP
• Page Down
• Control(Ctrl)
• Alternate(Alt)
• Escape(ESC)

9. From the Keyboard to the Computer
As you type, the processor in the keyboard is analyzing the key
matrix and determining what characters to send to the computer. It maintains
these characters in a buffer of memory that is usually about 16 bytes large. It
then sends the data in a stream to the computer via some type of connection.
A PS/2 type keyboard connector.

10. The most common keyboard connectors are:
5-pin DIN (Deustche Industrie Norm) connector
6-pin IBM PS/2 mini-DIN connector
4-pin USB (Universal Serial Bus) connector
internal connector (for laptops)
Normal DIN connectors are rarely used anymore. Most computers
use the mini-DIN PS/2 connector; but an increasing number of
new systems are dropping the PS/2 connectors in favor of USB. No
matter which type of connector is used, two principal elements
are sent through the connecting cable. The first is power for the
keyboard. Keyboards require a small amount of power, typically
about 5 volts, in order to function. The cable also carries the data
from the keyboard to the computer.

11. 3A-11
The Mouse
• All modern computers have a variant
• Allows users to select objects
– Pointer moved by the mouse
• Mechanical mouse
– Rubber ball determines direction and speed
– The ball often requires cleaning

12. 3A-12
The Mouse
• Optical mouse
– Light shown onto mouse pad
– Reflection determines speed and direction
– Requires little maintenance

13. 3A-13
The Mouse
• Interacting with a mouse
– Actions involve pointing to an object
– Clicking selects the object
– Clicking and holding drags the object
– Releasing an object is a drop
– Right clicking activates the shortcut menu
– Modern mice include a scroll wheel

14. 3A-14
The Mouse
• Benefits
– Pointer positioning is fast
– Menu interaction is easy
– Users can draw electronically

15. 3A-15
The Mouse
• Mouse button configuration
– Configured for a right-handed user
• Can be reconfigured
– Between 1 and 6 buttons
– Extra buttons are configurable

16. 3A-16
Variants of the Mouse
• Trackballs
– Upside down mouse
– Hand rests on the ball
– User moves the ball
– Uses little desk space

17. 3A-17
Variants of the Mouse
• Track pads
– Stationary pointing
device
– Small plastic rectangle
– Finger moves across the
pad
– Pointer moves with the
pointer
– Popular on laptops

18. TRACKBALL
• A trackball is a pointing device consisting of a ball
housed in a socket containing sensors to detect rotation
of the ball about two axes - like a mouse lying on its
back.
• The cursor is moved about the screen by a user rolling
the ball with their thumb, fingers, or the palm of their
hand.
• There are usually one to three buttons next to the ball,
which are in the same way as mouse buttons.

19. 3A-19
• Track point
– Little joystick on the keyboard
– Move pointer by moving the joystick

20. SCANNER
• Scanners allow information such as a photo or text to be
input into a computer.
• Scanners are usually either A4 size (flatbed), as shown
below, or hand-held to scan a much smaller area.
• If text is to be scanned, you would use an Optical Character
Recognition (OCR) program to recognize the printed text
and then convert it to a digital text file that can be accessed
using a computer.

21. JOYSTICK
• A joystick is a PC peripheral or general control device consisting of a handheld
stick that pivots about one end and transmits its angle in two or three
dimensions to a computer.
• Most joysticks are two-dimensional, having two axes of movement (similar to a
mouse), but three-dimensional joysticks do exist.
• A joystick is generally configured so that moving the stick left or right signals
movement along the X axis, and moving it forward (up) or back (down) signals
movement along the Y axis.
• In joysticks that are configured for three-dimensional movement, twisting the
stick left (counter-clockwise) or right (clockwise) signals movement along the Z
axis.

22. Output Devices
An output device is any hardware
component that conveys information to
one or more people. Three commonly
used output devices are a printer, a
monitor and speakers.

23. Examples of output devices:
• Speaker
• Headphones
• Screen (Monitor)
• Printer

24. SPEAKER
• Computer speakers, or multimedia speakers, are speakers external to a
computer, that disable the lower fidelity built-in speaker.
• They often have a low-power internal amplifier.
• Computer speakers range widely in quality and in price.
• The computer speakers typically packaged with computer systems are
small, plastic, and have mediocre sound quality. Some computer
speakers have equalization features such as bass and treble

25. Monitor
• A Monitor or Display (sometimes called a visual
display unit) is an electronic visual display for
computers.
• The monitor comprises the display device,
circuitry, and an enclosure.
• The display device in modern monitors is
typically a thin film transistor liquid crystal display
(TFT-LCD) thin panel, while older monitors use a
cathode ray tube about as deep as the screen
size.