Download Computer Hardware Basics

Computer Hardware Basics
Basic Electronics, PC Maintenance,
Upgrade and Repair
Computer Types
Personal computers
typically come in one of
three styles . . . .
The “desktop.” The
original computer, not
nearly as popular as it
used to be . . . .
The “tower.” The choice
of most consumers . . . .
And the laptop. Portable,
convenient, and very
difficult to work on.
Hardware - Power Supply
The power supply converts the
120VAC from the wall outlet to
DC voltage levels used by the
various computer components.
These voltages are typically
3.3V, 5V and 12V DC.
These voltages are used by
the motherboard, disk drives,
expansion cards, etc.
Hardware - Motherboard
A rectangular piece of circuit
board covered with many
conductors. Called a
“computer bus.” This bus
provides . . . .
Electrical energy paths to the
computer components and
expansion slots,
A way to distribute the digital
signals carrying data, control
instructions,
And small amounts of
electrical power to the many
different components mounted
on the board.
Hardware - Hard Drive
Also called the internal drive or
hard disk.
The location where all computer
programs and data are stored.
Made up of several disks (often
called platters) stacked inside a
sealed box.
Data and programs are stored
on the hard drive as magnetic
impulses.
It is connected to the power
supply by a wire harness made
up of several different colored
wires
Hardware - Hard Drive
Data is transmitted to and from
the hard drive through a flat
parallel ribbon cable connected
between the drive and the
motherboard.
Newer systems of today are
using smaller serial cables to
perform this function.
Hardware - CPU
Acronym for “Central
Processing Unit.” It is the
microprocessor and the brain
of the computer.
Contains millions of
microscopic electronic
components called transistors.
The transistors are electrically
connected in such a way that
they can interact with computer
programs and process data.
Hardware - CPU
The CPU controls the data in the
computer.
Commands are issued to the CPU
via software and it translates the
commands into actions.
The CPU does not think or
possess human intelligence. It
simply carries out the program
codes written in the software
program.
Hardware - RAM
Acronym for “Random Access
Memory.”
It is the location where computer
programs are loaded from the
hard drive.
Is classified as volatile memory,
which means that the data and
programs loaded in it are lost
when computer power is turned
off.
Usually mounted in several
parallel slots on the
motherboard.
Hardware - RAM
RAM is a place where data is
temporarily stored. It is emptied
when the computer turns off.
When the PC is turned back on,
new information is loaded into
the RAM.
Hardware - BIOS and CMOS
BIOS is acronym for “Basic
Input/Output System.
Stored in a special kind of memory
chip called an EEPROM, formerly
just a PROM.
Consists of software programs
that support the compatibility
between the CPU and devices like
the hard drive, CD-ROM drive and
the monitor.
BIOS can be updated by “flashing”
the EEPROM with the updated
BIOS program.
Hardware - BIOS and CMOS
CMOS is an acronym for
“complimentary metal oxide
semiconductor”, which describes
the electronic technology to
construct the chip (integrated
circuit).
BIOS setup information is stored
in the CMOS chip. Information
such as the date and time, as well
as information about the
computer’s hardware.
A battery on the motherboard is
used to hold the information in
CMOS even after the computer is
turned off.
Hardware - Expansion Cards
Expansion cards are often
called interface cards or host
adapters.
They allow the computer to be
custom-designed to meet the
needs of different consumers.
It may allow upgrade from a
less capable motherboard
integrated circuitry.
The expansion cards fit into
slots on the motherboard.
Typical types of slots are ISA,
EISA, and PCI.
Network
Card
Video
Card
Audio Card
Hardware - Cooling Fans
Cooling fans provide a constant
stream of air across the computer
components.
The typical CPU comes with a fan
mounted directly on top of it to
assist in the cooling process.
Heat KILLS! Electronic
components are damaged or
destroyed by excessive heat.
Hardware - Cables
Cables connect all of the
computer systems together.
There are many different types
of cables inside a PC.
Flat ribbon cables are used to
connect the motherboard to the
hard drive, CD-ROM drive and
floppy drive.
Flat ribbon cables consist of
many parallel conductors
covered in insulation.
Today’s hard disk drives use
SATA cables instead of parallel
ribbon cables.
Hardware - Cables
Higher levels of electrical
power can’t run through
ribbon cable. Therefore,
separate wiring harnesses
from the power supply are
used.
There are also a lot of
external cables used to
connect various peripheral
devices.
Hardware - Other Devices
Floppy Drives – a floppy drive
reads and writes to a 1.44MB
magnetic floppy disk. It stores
small amounts of data.
CD-ROM Drive – (Compact Disk
Read Only Memory Drive) A drive
that can read large amounts of
data from a CD-ROM using a
laser beam of light.
DVD Drive – (Digital Versatile Disk
Drive) A drive that reads data from
a DVD using a laser beam of light.
DVD offers the highest storage
capacity of all laser-based CD’s
thus far.
Electrostatic Discharge
Abbreviated “ESD”, is best defined in the world of
computer maintenance as the transfer of static
electrical energy from one object to another.
Usually created by friction.
When two dissimilar materials are rubbed together, an
electric charge is produced.
Integrated circuits (IC’s) in a computer are very small,
and made of material that is very susceptible to ESD.
The electrostatic discharge will damage (destroy) the
IC.
Electrostatic Discharge
To avoid ESD, technicians wear a ground strap when handling static
sensitive devices.
The anti-static wrist strap bleeds off any static charge buildup on a
technician’s body and sends it to ground..
Also, when working with static sensitive material outside of the PC
case, a static “mat” should be used. It works similarly to the wrist
strap.