Post on 11-Apr-2017
Chapter 2The Visible PC
MELJUN CORTESMELJUN CORTES
© 2007 The McGraw-Hill Companies, Inc. All rights reserved
OverviewIn this chapter, you will learn to
Describe how the PC worksIdentify the essential tools of the trade and
avoid electrostatic discharge (ESD)Identify the major internal and external
components of a PCIdentify the different connectors on a typical
PC system unit
How the PC Works
`Input
Output
Processing
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How the PC WorksSoftware
Operating system (Windows, MAC OS X, Linux)
Applications (PowerPoint, Word, Outlook, Internet Explorer)
HardwarePieces you can touch (mouse, monitor,
motherboard, etc.)
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How the PC WorksComputer functions through four stages:
Input provides the computer with dataKeyboard and mouse
Processing occurs when the computer processes or manipulates your data
Output is provided as the result of processing your dataMonitor, printer, speakers
Storage is how you keep your data for later useHard drive, CD-ROM disc, floppy diskette
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How the PC WorksThe Art of the PC Technician
Hardware and software interact to accomplish the four stages
Your goal is to understand all the parts and how they interact in the various stagesBy understanding how it works, you’re better able to fix it
when it breaks
`
Broken PC PC tech Fixed PC
`
Tools of the Tradeand ESD Avoidance
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PC Tool KitThe basic tech toolkit: a Phillips-head screwdriver
Most toolkits contain a few other items It’s a good idea to include
Magnifying glassSmall flashlight
IT EssentialsCompTIA A+Essentials
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Electrostatic DischargeElectrostatic discharge (ESD) is the passage of a
static electrical charge into your PC or a PC component such as a RAM stick
Static electricity can destroy sensitive parts of a PC
ESD damage is much more prevalent in dry, cool environments
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Anti-static ToolsAnti-static wrist strap
Keeps you and the PC at the same electrical potential to prevent ESD
Anti-static matsUsed temporarily to place
parts taken out of your PCAnti-static bags
Used to store electrical components from your PC
Always unplug a PC when you work on it. Don’t just turn it off.
The Complete PC
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External ConnectionsPlug goes into a portPort/jack accepts a plugConnector can be either a port or a plug
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DIN ConnectorsDIN connectors are round and
come in two sizes:DINMini-DIN
Always a female connector
Used frequently by a keyboard or mouse
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USB ConnectorsUniversal Serial Bus
(USB)Used by many devices
todayDevices are hot-
swappable You can insert or remove the
device while the PC is powered on
USB B plugs into devicesUSB A plugs into
computers
USB B
USB A
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FireWire ConnectorsFireWire connectors move data at incredibly
high speedsAlso known as IEEE 1394Popular with video applicationsUses 6-wire connector (note the rounded edge)Hot-swappable
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DB ConnectorsDB connectors have a slight D-shape
Male DB connectors have pinsFemale DB connectors have socketsOldest type of connector in the PC
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RJ ConnectorsRegistered jack or RJ
connectors
RJ-11 used by telephone lines
RJ-45 used in network interface cards (NICs)
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Audio ConnectorsAudio connectors are
used on sound cards
Used to connect speakers, microphones, and other audio devices
Devices and Their Connectors
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Cards vs. OnboardConnectors exposed on
rear and front of PCs
Some connectors attach directly to motherboard
Some connectors attach to boards that plug into motherboard
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KeyboardKeyboards connect into dedicated mini-
DIN (usually purple) or USB
Plugs and ports usually purple
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Video CardsVideo cards connect to monitors
S-Video connector (left)Digital video interface (DVI) connector (center) 15-pin female DB connector (right)
Newer High-Definition Multimedia Interface (HDMI)
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Sound CardsSound cards
Convert digital information into soundConvert sound from a microphone into digital dataMini-audio jacks for speakers and microphonesDB-15 connector for a joystick or musical instrumentNewer Sony/Phillips Digital Interface Format (S/PDIF)
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Network CardsNetworks: groups of PCs connected together
Network interface cards (NICs) typically on motherboard (can be expansion card)
Typical connector is RJ-45
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MouseA mouse enables you to
select graphical items on a screen
Connects through mini-DIN port (usually light green) or USB port (most common)
Trackball may be used instead of mouse
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ModemModems convert analog telephone signals into
digital data and vice versa
Internal modems are expansion cards
External modems connect to a serial port
Uses two RJ-11 socketsOne to the telephone jack in the wallOne to a telephone if you wish
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Serial PortsSerial ports are used to add external devices to a PC
Accept and transmit serial data
Male DB-9 or DB-25
Largely replaced by USB
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PrinterPrinters output data from the PC onto paper
Historically used a female DB-25
Today printers almost exclusively use a USB or FireWire port
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Joystick Joysticks are used almost
exclusively to play games on the computer
Originally designed as an input device to be used like a mouse
Connector typically orange
Most joysticks now use USB
Inside the System Unit
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CaseThe case houses all of the internal components
Protects internal componentsExternal connections in front and rearProvides access to storage devices such as CDs
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CPUCentral processing
unit (CPU)
Also called a microprocessor
Performs calculations
CPUs generate a lot of heatCooling fan and/or heat
sink used to keep them cool
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CPUMakes
IntelAMD
ModelsCeleronAthlonSempronPentium
• CPUs come in different packages– Pin grid array (PGA)
• Most common today
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RAMRandom access memory (RAM)
Stores programs and data currently used by the CPU
Measured in megabytes (MB) and gigabytes (GB)
Each piece or module of RAM is called a stickDual inline memory module (DIMM) most common today
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MotherboardThe motherboard is a thin, flat
piece of circuit board
Everything connects directly or indirectly to the motherboard
Contains sockets for the CPU, RAM, power, and external devices such as mice, printers, and keyboards
Expansion slots allow the addition of new components
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Power SupplyProvides electrical power to PC
componentsUses 110VAC power from the
wall outlet
Has power connectors for the motherboard and other devices
Uses a fan to keep itself and the PC cool inside
Safety Alert High voltage capacitor holds power
after unplugged
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Floppy DriveThe floppy drive uses floppy diskettes to store data
Connects to the computer via a ribbon cable
Connects to the floppy controller on the motherboard
Uses a connector from the power supply
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Hard DriveHard drives store programs and data not currently in
use by the CPUCapacity quoted in megabytes (MB) or gigabytes (GB)A typical PC has one hard drive but may contain moreCommon types include
Parallel AT attachment (PATA) Serial AT attachment (SATA) Small computer system
interface (SCSI)
Uses a power cable from the power supply
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Optical MediaTwo groups
CD Stores about 700 MB CD-ROM (read only) CD-R, CD-RW (allows writing
to CD)
DVD Stores about 4 GB of data DVD-ROM, DVD+R, DVD-R,
DVD+RW, DVD-RW
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