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The Visible PCChapter 2

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Overview

• In this chapter, you will learn to

– Describe how the PC works– Identify the essential tools of the trade and avoid

electrostatic discharge (ESD)– Identify the major internal and external

components of a PC– Identify the different connectors on a typical PC

system unit

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How the PC Works

`Input

Output

Processing

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How the PC Works

• Software– Operating system (Windows, MAC OS X, Linux)– Applications (PowerPoint, Word, Outlook, Internet

Explorer)

• Hardware– Pieces you can touch (mouse, monitor,

motherboard, etc.)

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How the PC Works

• Computer functions through four stages:– Input provides the computer with data

• Keyboard and mouse

– Processing occurs when the computer processes or manipulates your data

– Output is provided as the result of processing your data

• Monitor, printer, speakers

– Storage is how you keep your data for later use• Hard drive, CD-ROM disc, floppy diskette

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How the PC Works

• The 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 stages• By understanding how it works, you’re better able to fix it

when it breaks

`

Broken PC PC tech Fixed PC

`

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Tools of the Tradeand ESD Avoidance

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PC Tool Kit

• The basic tech toolkit: a Phillips-head screwdriver – Most toolkits contain a few other items

• It’s a good idea to include– Magnifying glass– Small flashlight

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IT Essentials

CompTIA A+Essentials

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Electrostatic Discharge

• Electrostatic 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 Tools

• Anti-static wrist strap– Keeps you and the PC at

the same electrical potential to prevent ESD

• Anti-static mats– Used temporarily to place

parts taken out of your PC

• Anti-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.

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The Complete PC

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External Connections

• Plug goes into a port• Port/jack accepts a plug• Connector can be either a port or a plug

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DIN Connectors

• DIN connectors are round and come in two sizes:– DIN– Mini-DIN

• Always a female connector

• Used frequently by a keyboard or mouse

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USB Connectors

• Universal Serial Bus (USB)– Used by many devices

today– Devices are hot-

swappable• You can insert or remove

the device while the PC is powered on

– USB B plugs into devices

– USB A plugs into computers

USB B

USB A

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FireWire Connectors

• FireWire connectors move data at incredibly high speeds– Also known as IEEE 1394– Popular with video applications– Uses 6-wire connector (note the rounded edge)– Hot-swappable

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DB Connectors

• DB connectors have a slight D-shape– Male DB connectors have pins– Female DB connectors have sockets– Oldest type of connector in the PC

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RJ Connectors

• Registered jack or RJ connectors

• RJ-11 used by telephone lines

• RJ-45 used in network interface cards (NICs)

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Audio Connectors

• Audio connectors are used on sound cards

– Used to connect speakers, microphones, and other audio devices

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Devices and Their Connectors

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Cards vs. Onboard

• Connectors 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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Keyboard

• Keyboards connect into dedicated mini-DIN (usually purple) or USB

• Plugs and ports usually purple

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Video Cards

• Video 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 Cards

• Sound cards – Convert digital information into sound– Convert sound from a microphone into digital data– Mini-audio jacks for speakers and microphones– DB-15 connector for a joystick or musical instrument– Newer Sony/Phillips Digital Interface Format (S/PDIF)

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Network Cards

• Networks: 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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Mouse

• A 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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Modem

• Modems 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 sockets• One to the telephone jack in the wall• One to a telephone if you wish

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Serial Ports

• Serial 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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Printer

• Printers 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

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Inside the System Unit

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Case

• The case houses all of the internal components– Protects internal components– External connections in front and rear– Provides access to storage devices such as CDs

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CPU

• Central processing unit (CPU)

– Also called a microprocessor

– Performs calculations

– CPUs generate a lot of heat

• Cooling fan and/or heat sink used to keep them cool

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CPU

• Makes– Intel– AMD

• Models– Celeron– Athlon– Sempron– Pentium

• CPUs come in different packages– Pin grid array (PGA)

• Most common today

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RAM

• Random 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 stick• Dual inline memory module (DIMM) most common today

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Motherboard

• The 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 Supply

• Provides electrical power to PC components– Uses 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 Drive

• The 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 Drive

• Hard drives store programs and data not currently in use by the CPU– Capacity quoted in megabytes (MB) or gigabytes (GB)– A typical PC has one hard drive but may contain more– Common 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 Media

• Two 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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