Chapter 04-Chapter 04-Form Factors and Power Form Factors and Power

SuppliesSupplies

Form Factors and Power Form Factors and Power SuppliesSupplies

In this chapter you will learn:In this chapter you will learn: About different form factors and About different form factors and

computer casescomputer cases How electricity is measuredHow electricity is measured How to protect your computer system How to protect your computer system

against damaging changes in electrical against damaging changes in electrical powerpower

How to troubleshoot electrical problemsHow to troubleshoot electrical problems

Computer Case, Motherboard Computer Case, Motherboard and Power Supply Form and Power Supply Form

Factors-pg.132Factors-pg.132 Form Factor: describes the size, Form Factor: describes the size,

shape and major features of a shape and major features of a hardware componenthardware component

Chassis: another word for computer Chassis: another word for computer casecase

Types of Form Factors-Types of Form Factors-pg.133pg.133

BTX, ATX, LPX, NLX, Backplane BTX, ATX, LPX, NLX, Backplane Systems and the outdated ATXSystems and the outdated ATX

Most Common:Most Common: ATX, MicroATX, BTX and NLXATX, MicroATX, BTX and NLX

AT Form FactorAT Form Factor Sometimes called “Full AT”Sometimes called “Full AT” Measures at 12” x 13.8”Measures at 12” x 13.8” Supplies the system with +5, -5, Supplies the system with +5, -5,

+12, -12 Volts DC+12, -12 Volts DC P8 and P9 Power ConnectorP8 and P9 Power Connector

Baby AT Form Factor pg.134Baby AT Form Factor pg.134 Smaller version of the AT form factorSmaller version of the AT form factor Backwards compatible with the AT Backwards compatible with the AT

form factorform factor Used from 1993 to 1997Used from 1993 to 1997

ATX Form FactorATX Form Factor Most commonly used todayMost commonly used today Developed in 1995 by IntelDeveloped in 1995 by Intel Better position of componentsBetter position of components Reduced potential of EMI (Electro Reduced potential of EMI (Electro

magnetic interference)magnetic interference) Measures 12” x 9.6” so its smaller Measures 12” x 9.6” so its smaller

that an AT motherboardthat an AT motherboard

ATX Form FactorATX Form Factor The first ATX power supplies and The first ATX power supplies and

motherboards used a P1 power motherboards used a P1 power connectorconnector

Provide the computer with: -3, +3, -5, Provide the computer with: -3, +3, -5, +5, -12, +12 volts of DC current+5, -12, +12 volts of DC current

P1 connector uses 20 pins and ATX P1 connector uses 20 pins and ATX ver.2.2 uses 24 pinsver.2.2 uses 24 pins

Power supplies with the extra 4 pins are Power supplies with the extra 4 pins are also called ATX12Valso called ATX12V

MicroATX Form Factor MicroATX Form Factor pg.137pg.137

Variation of the ATXVariation of the ATX Reduces cost by reducing I/O portsReduces cost by reducing I/O ports Smaller power supplySmaller power supply Smaller caseSmaller case

BTX Form FactorBTX Form Factor BTX (Balanced Technology Extended)BTX (Balanced Technology Extended) Designed by Intel to be used by Designed by Intel to be used by

everything big and smalleverything big and small Takes full advantage of SATA, USB Takes full advantage of SATA, USB

2.0 and PCI Express2.0 and PCI Express Use a 24 pin power connectorUse a 24 pin power connector Improved wind tunnel effect pg.138Improved wind tunnel effect pg.138

LXP and Mini-LPX Form LXP and Mini-LPX Form FactorsFactors

Developed by Western DigitalDeveloped by Western Digital One expansion slot with a riser card One expansion slot with a riser card

or bus riser or daughter cardor bus riser or daughter card Uses low profile cases and slim line Uses low profile cases and slim line

casescases Can only use the manufacturers Can only use the manufacturers

power suppliespower supplies

NLX Form FactorNLX Form Factor Low end personal computer Low end personal computer

motherboard developed by Intel in motherboard developed by Intel in 19981998

Improvement over LPXImprovement over LPX

Backplane SystemsBackplane Systems Do not use a true motherboardDo not use a true motherboard Active backplanes contain bus Active backplanes contain bus

connectors, buffer and driver circuitsconnectors, buffer and driver circuits Passive backplanes contain not Passive backplanes contain not

circuitry at allcircuitry at all Used for rack mounted systemsUsed for rack mounted systems Built for easy accessBuilt for easy access

Types of cases pg.140Types of cases pg.140 Desktop casesDesktop cases Tower casesTower cases

Desktop CasesDesktop Cases Desktop case doubles as a monitor Desktop case doubles as a monitor

standstand Low end desktops: compact cases, Low end desktops: compact cases,

low-profile cases or slim line caseslow-profile cases or slim line cases Use the NLX, LPX and Mini-LPX form Use the NLX, LPX and Mini-LPX form

factorfactor

Tower CasesTower Cases Tower cases can be as high as two Tower cases can be as high as two

feetfeet Often used for serversOften used for servers Good for upgradingGood for upgrading Use the ATX, Mini-ATX and BTX form Use the ATX, Mini-ATX and BTX form

factorsfactors

Notebook CasesNotebook Cases Proprietary- Can only be purchased Proprietary- Can only be purchased

from the vendor. Example: Dell, from the vendor. Example: Dell, Toshiba, Sony etc.Toshiba, Sony etc.

All are different in size and power All are different in size and power supply, no set standards.supply, no set standards.

Measures and Properties of Measures and Properties of Electricity pg.143Electricity pg.143

AC and DCAC and DC AC-Alternating CurrentAC-Alternating Current AC goes back and forth (oscillates) at AC goes back and forth (oscillates) at

60Hz or 60 times in one second60Hz or 60 times in one second Alternates from -110v to +110vAlternates from -110v to +110v

AC and DCAC and DC DC-Direct CurrentDC-Direct Current Travels in only one directionTravels in only one direction Most electronics use DCMost electronics use DC A rectifier converts AC to DC like in a A rectifier converts AC to DC like in a

power supplypower supply A transformer changes the amount of A transformer changes the amount of

current current A power supply uses a rectifier and a A power supply uses a rectifier and a

transformertransformer

Hot, Neutral and Ground Hot, Neutral and Ground pg.144pg.144

Hot-the hot connector is the source Hot-the hot connector is the source of the electricityof the electricity

Neutral-the neutral connectors is the Neutral-the neutral connectors is the path back to the power station for path back to the power station for the electricitythe electricity

Electricity flows from Hot to NeutralElectricity flows from Hot to Neutral Ground is an escape route for out of Ground is an escape route for out of

control electricity like in a shortcontrol electricity like in a short

Hot, Neutral and GroundHot, Neutral and GroundFusesFuses Fuses are rated in AMPSFuses are rated in AMPS They are made to prevent too much They are made to prevent too much

current from flowing through a circuitcurrent from flowing through a circuit

Receptacle TesterReceptacle Tester A receptacle tester is used to verify A receptacle tester is used to verify

that hot, neutral and ground are that hot, neutral and ground are wired correctlywired correctly

Some Common Electrical Some Common Electrical Components pg.146Components pg.146

Transistor- serves as a gate or a Transistor- serves as a gate or a switch for an electrical signal and can switch for an electrical signal and can amplify the flow of electricity.amplify the flow of electricity.

Some Common Electrical Some Common Electrical ComponentsComponents

CapacitorCapacitor- an electronic device that - an electronic device that can hold an electrical charge for a can hold an electrical charge for a period of time and can smooth the period of time and can smooth the uneven flow of electricity through a uneven flow of electricity through a circuit.circuit.

Used in power suppliesUsed in power supplies Can be dangerous even when Can be dangerous even when

unpluggedunplugged

Some Common Electrical Some Common Electrical ComponentsComponents

DiodeDiode-allows electricity to flow in -allows electricity to flow in only one direction.only one direction.

One to four diodes in various One to four diodes in various configurations is called a rectifier and configurations is called a rectifier and is used to convert AC to DCis used to convert AC to DC

Some Common Electrical Some Common Electrical ComponentsComponents

ResistorResistor- a resistor limits the amount - a resistor limits the amount of current that can flow through it.of current that can flow through it.

Used to protect a circuit from over Used to protect a circuit from over loadload

Resistors are color coded to indicate Resistors are color coded to indicate the level of resistance measured in the level of resistance measured in OhmsOhms