1.0 Personal Computer Components
Identify the names, purposes and characteristics of input
devices for example: mouse, keyboard, bar code reader, multimedia (e.g. web
and digital cameras, MIDI, microphones), biometric devices, touch
Mouse, and keyboard are essential parts of a personal computer, and brief
description given below:
A mouse is an input device that is used to select and click an
object on a computer screen. The Mouse is represented by a pointer (arrow) on
your monitor. Types of mouse:
1. Mechanical mouse: Mechanical mouse uses rollers to find
relative position of the mouse. The design has been used for several years, but
it is being over taken by Optical mouse. The biggest disadvantage of mechanical
mouse is that it requires periodic cleaning of the moving parts for proper
functionality. The mouse is connected to the motherboard using USB or PS/2
2. Optical mouse: This type of mouse uses optical sensing for
finding the relative position of mouse pointer. Since it involves no moving
parts, there is no maintenance required on the mouse parts. It is rugged, and
convenient to use. But, it is still connected to the motherboard using a cable.
3. Laser mouse: This type of mouse uses
rf/laser to communicate
with the CPU box. As it is free from moving parts, and connected to the CPU box
without any wires, it is most convenient to use. However, it is more expensive
compared with mechanical or optical mice.
Mouse buttons: Normally there are two buttons associated with a
mouse. One button (usually left button) is used to select any object on the
screen (and fire any event). The right mouse button is used to bring up any
contextual menu when clicked. Optionally, there will be a middle button, or a
wheel that can be used to navigate through the screen display.
Mechanical Mouse (Top)
Mechanical (ball) mouse Bottom View
The different mouse operations are:
Point: Move the mouse so that the mouse pointer rests on the required object
(for example, an icon, or a file name). The tip of the mouse arrow must be on
Click: Press and release a mouse button. This operation usually selects the
Double-click: Click a mouse button twice in quick succession. Do not move the
mouse between clicks. Double-clicking usually selects an object and performs an
operation. For example, double-clicking on an application icon runs the
Drag-n-drop: Point at an object, press a mouse button, hold it down, move the
mouse to a new position, then release the mouse button. Dragging is used to
select a section of text or other objects and to move objects to a new position.
Some mouse settings that you may wish to change are:
Button configuration: You can configure for right-handed or left-handed
Double-click speed: If you have difficulty double-clicking, you may reduce
the double click speed, and vice versa.
Pointer speed: If you have difficulty pointing with accuracy, you may
reduce the pointer speed to suit your response times, and vice versa.
To reconfigure the mouse:
At the Start menu, from the Settings panel choose Control Panel
In the Control Panel window, double-click on Mouse dialog box
The right/left mouse buttons and double-click speed can be set from the
Pointer speed can be changed from the Motion tab
A keyboard is the most widely used input device for a personal
computer. A typical keyboard is shown in the figure below:
A computer Keyboard looks much like a typewriter keyboard,
except that it has extra keys.
The Function Keys (F-keys) perform specific actions. Different software use
the Function Keys differently. The Function Keys are located across the top of
the keyboard and are labeled F1, F2, …F12
There are three Modifier Keys on a keyboard: SHIFT, ALT, and CTRL. You use
these keys in combination with another key(s).
BACK SPACE and/or DELETE are editing keys used to erase. BACK SPACE erases to
the left of the cursor location; DELETE erases the current cursor
Directional arrows (Right, Left, Up, and Down), also called Cursor Movement
Keys are used to move the cursor around in the document one character or one
line at a time.
You can access Keyboard dialog box in a Windows computer by going to Control
Panel, and double clicking Keyboard dialog box.
You can configure Character repeat delay, cursor blink rate, and
other parameters as shown above. Normally, default setting will be sufficient
for most users.
Commonly used multimedia devices include web cameras,
microphones, and MIDI.
Web camera: A web camera, also called
webcam, is a real-time
camera (usually a video camera) that works in conjunction with a PC, and webcam
software. The video or images produced by webcam can be accessed using the
Internet applications such as instant messaging. Webcam images and videos are
normally taken using low resolution camaras for facilitating fast transmission
on the Internet.
Microphone: A microphone is used to record the voice, and
normally used for voice/video communication over the Internet.
It is an acronym for Musical Instrument Digital Interface. It is
used for controlling devices, such as synthesizers and sound cards. At minimum,
a MIDI representation of a sound includes values for the note's pitch, length,
and volume. A number of software programs are available for composing and
editing music that conforms to the MIDI standard.
You can configure MIDI devices using Sounds and Multimedia
dialog box in the Control Panel.
Biometric devices provide biological identification of a person,
and may include eyes, voice, handprints, fingerprints and hand-written
signatures. Finger print scanner is an example of a biometric device.
A touch screen is a computer display screen that is sensitive to
human touch. Users can interact with the computer by touching pictures or words
on the touch screen. Touch screens are used with information kiosks,
computer-based training devices, and systems designed to help individuals who
have difficulty manipulating a mouse or keyboard. Some applications, such
as games are designed specifically for touch screen technology. Monitors are
available with built-in touch screen technology.
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