Thursday, September 25, 2014
Tuesday, March 19, 2013
Chapter 10
Monitor
PCs use one of two monitor
technologies: a traditional "glass bottle" CRT monitor or a
flat-panel display (FPD) that uses LCD technology.
Monitor Overview
Color monitors can display
anywhere from 16 to over 1 million different colors. Color monitors are
sometimes called RGB monitors because they accept three separate signals --
red, green, and blue.
The resolution of a monitor
indicates how densely packed the pixels are. In general, the more pixels (often
expressed in dots per inch), the sharper the image. Most modern monitors can
display 1024 by 768 pixels, the SVGA standard. Some high-end models can display
1280 by 1024, or even 1600 by 1200.
How to Choose a Monitor
If you're a graphics professional,
you may prefer a CRT monitor because they are said to show more realistic
colors. However, the latest high-end LCDs can also give equal color quality.
If you with text most of the time,
a LCD is a good choice because the various pixels that you find on a LCD will
have nicely defined edges. This gives sharp and focus letters on the screen.
Chapter 9
Cases and Power Supplies
A computer's case is more than a
box. The case includes the drive cage, the internal compartment that holds disk
drives, and almost always the power supply, among other features, all of which
we discuss in this chapter.
Cases
Most people think of a case as
merely the enclosure that holds a PC together. That view is reasonable for
people who buy a PC and never open the case, but anyone who builds or upgrades
PCs soon realizes that not all cases are created equal. This section describes
what you need to know about cases.
Cases Overview
The computer case is your
computer's housing. You need this to store your components, the largest of
which is your motherboard. A good quality case can have a big impact on the
performance and durability of the computer. Cases sold have to meet
requirements for shielding against both external RFI and interference to
external devices that is generated by the computer.
Good cases are designed to provide
for proper airflow to keep the components from overheating. Well made cases do
not have a thin tinny feel or sound when you tap on them. They have rolled
edges to prevent injury. Panels should fit together well without requiring
excessive effort. When the computer is running, a good case does not make
excessive vibration noises. Other attributes of good cases include ease in
opening and ease in accessing internal components.
Case Components
Cases come with various
components, as shown in below figure.
Most of these components are
self-explanatory. Drive bays are areas in the front for installation of
removable media (CD, DVD, floppy, Zip, etc.). The 5 1/4-inch bays are for all
but the floppy drives. Cases usually come with small speakers, which are there
to provide very basic sounds to the user. About all these speakers play are
warning beeps and the sound of a modem connecting. These speakers are very important,
because multimedia speakers don't work before Windows has booted, if Windows is
in Safe Mode, or if there is a problem with the sound card.
While many older PCs had key
locks, few newer ones do. Locking a computer prevents it from being powered on.
The most important indicator lights are the ones that show that power is on and
that the main hard drive is active. The hard drive indicator is helpful to show
if the hard drive is running too much, or if the computer is locked up. On
recent cases, the only button is the power button. Older cases might have a
Reset button, which simply turns power off and on, and a "Turbo"
button. Leave the Turbo button in the On position unless a tech support
technician tells you to turn it off.
Chapter 8
Floppy Drive and CD-ROM Drives
Here you will learn Floppy Disk,
CD-Rom and CD Writers.
Floppy Disk Drives
A 3.5" square holding a
flexible magnetic disc that holds information or data. You need a floppy drive
to read the floppy. A floppy disk can hold only 1.44 megabytes, but it is
portable and allows you to make copies of your files.
CD-ROM Drives
A CD-ROM drive used to be an 'optional
extra' in computers - it is no longer so. Most software packages come in CD
format, so you must have a CD-ROM drive to read them. Typically, CD-ROM drives
today need to be at least 24X speed to keep up with the newer software
applications out there.
A CD drive connects to the
computer motherboard through two types of cables. The older and more common
connection is through the IDE Ribbon cable. Recently SATA (Serial ATA) drives
have been produced and will gradually become more common. The benefits of
having SATA cables is that they are smaller and the transfer rate is higher.
Floppy drives were the main source
of data transfer and files were small enough to fit on them. However, today
even CD drives are getting out of date and are fast being replaced by the DVD
ROM and DVD RW Drives.
Chapter 7
Input Devices
Input devices are devices that
allow the user to input data into a computer. The most obvious input devices
are Mouse and keyboards.
Keyboards
The keyboard is the main input
device for most computers. There are many sets of keys on a typical “windows”
keyboard. On the left side of the keyboard are regular alphanumeric and
punctuation keys similar to those on a typewriter. These are used to input
textual information to the PC.
A numeric keypad on the right is
similar to that of an adding machine or calculator. Keys that are used for
cursor control and navigation are located in the middle. Keys that are used for
special functions are located along the top of the keyboard and along the
bottom section of the alphanumeric keys.
Keyboards are mainly divided into
two types:
1. Multimedia keyboard.
2. Ordinary Keyboard.
Subscribe to:
Posts (Atom)