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Central Processing
Unit (CPU) and Microcontrollers: The most significant
components of computer is its Central Processing Unit or Processor.
The processor is the heart and brain of the computer system. The more
powerful the processor, the faster the system goes. Processor power is often
measured by its clock frequency (on the computer slang - clock speed) in
MHz or GHz. However, clock speed alone may not be the determining factor. Real
speed of such functions as calculation or data acquisition for
processors with 1 GHz and 2 GHz, can differ essentially by less then 2 times.
Best way to choose a processor is through an analysis of its rate. Most modern electronic devices (TVs, VCRs, microwaves, watches and so
on) contain an embedded microcontroller. It's basically a dedicated
computer.
Memory: Memory is almost as important as
the processor, because it also influences the real
speed of the computer. You may actually get better performance with
less-powerful processor and more memory, than you would with the most
powerful processor and less memory. Memory is measured in megabytes
(MB) or gigabytes (GB). Memory comes in a variety of packages, pin configurations, types,
and formats. Today, there are three varieties of memory in common use: SDRAM, DDR
SDRAM. and RDRAM
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RAM (Random Access Memory ) is the short term temporary workspace
that the processor uses to store and manipulate information
SDRAM (synchronous dynamic RAM) is new
standard memory offered in PC. It provides single-channel
memory and is available on our mainstream and value desktop systems DDR SDRAM (double data rate synchronous
dynamic RAM) takes all the features of ordinary SDRAM. Allow 1.066 gigabyte transfer rates on a motherboard's 66MHz bus -
RDRAM (Rambus dynamic RAM) is able to load
a new stream of data before the previous stream has completed,
resulting in faster access speeds Dual Channel RDRAM is shipped on desktop systems powered by Pentium 4
processors. Can operate at motherboard bus clock of 133MHz. Can transfer data 533Mb/s per channel.
 Hard drive ( Hard Disk Drive -HDD) is another type of memory, which stores programs and
information. HDD records data onto fixed platters spinning in an
environmentally-controlled container. Hard disks have generally fast access times and connect to
the computer via special interfaces, (IDE,
SCSI, etc). Hard drives can be
internal (inside of case) and external. The needed capacity of the hard drive
depends on how many applications you will use. Usually, without games, 20 GB is good
enough.
 Video and Sound cards:
The video card and its performance level are tied tightly to the performance of the other
components in the computer system. A PC with a top caliber processor will have faster
video performance than one with a slower CPU, all else being equal.
The type of motherboard (and a chipset), the amount and type of
memory, the size of system cache all also have an effect, as does the system bus.
The degree to which video performance is tied to the processor performance
depends on the application. The same is true for sound cards.
It is best to not change the Video and Sound cards, recommended
by manufacturer.
 Computer cases:
The case holds the motherboard, drives, cooling systems, power supply system,
and so on. It also protects the system from the outside world. Case can have the different forms:
desktop, tower, mid
tower, there are on the market the computers with everything inside of keyboard (CYBERNET,
Inc.) , or flat panel (IBM) and other unusual forms. Sometimes
companies create "form-factor" cases (or type of physical arrangement of
a computer hardware object). For example, IBM used many
form-factors: desktop, integrated Flat panel PC, mini desktop, small form
factor, and tower. When buying a computer , make sure that case is
expandable. There is nothing worse than needing a new hard drive and not having
any room for it. The case is also the item that helps to connect together all
computer equipment. It means, that it must have all necessary jacks and
ports. Also, make sure the case looks good. An ugly case can be a real
reason to swap a good computer.
Power supply unit (PSU). Manufactures offer a variety of computer
power supplies for all computing needs. Power sources range
from AC and DC adapters, power inverters, and many more options, helping
customers not only work in office, but also get out of the
office and into the world. Usually Power
supplies converts 110-115 or 220-230 volt alternating current (AC)
into a steady low-voltage direct current (DC) usable by the computer.
AC inputs include input voltage and input frequency. Choices for
input voltage include 115 VAC and 230 VAC. Input frequencies for
computer power supplies can be 50 Hz, 60 Hz, or 400 Hz. Common choices
for DC output voltage include +/- 3.3 V, +/- 5 V, +/- 12 V, +/- 15 V,
+/- 24 V, and +/- 48 V. Power supplies generate a large amount of heat
in the process of converting the high voltage current into the lower
voltage currents. This is reason why active cooling fans have
always been placed inside of computer power supplies. Many of the newer
power supplies will often have 2 fans, one to pull air into the unit and
one to expel the hot air out of the unit.
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