Basic Hardware

7/28/2019 Basic Hardware

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Module 6 HARDWARE MAY 20

ADCPM PC ASSEMBLING

~ ~ ~ INDEX ~ ~ ~

TOPIC PAGE

WHAT is ELECTRONICS.. ....................... 02

ELECTRONIC COMPONENTS ....................... 02

DIGITAL ELECTRONICS. ....................... 03

LOGIC CIRCUITS (GATES) ....................... 03~ 0

CMOS and its FEATURES ....................... 06

POST BEEP CODES. ....................... 07

SMPS. ....................... 08 ~ 1

SMPS SECTIONS and COMPONENTS ....................... 09

SMPS TYPES, AT & ATX POWER SUPPLY. ....................... 10~ 1

TROUBLESHOOTING the SMPS. ....................... 13

MONITORS .. ....................... 13 ~ 2

MONITOR TYPES. ....................... 15 ~ 1

PERSONAL COMPUTER MOTHERBOARD. ....................... 20 ~ 2

THECENTRAL PROCESSING UNIT ....................... 25 ~ 2

INTRODUCTION to USB DEVICES... ....................... 28 ~ 3

PC ASSEMBLING ....................... 32 ~ 3

DISASSEMBLING the COMPUTER . ....................... 35

COMPUTER CONNECTOR and INTERFACES.. ....................... 36 ~ 3

UPS OVERVIEW... ....................... 39 ~ 4

Note: If you find any typing or printingerror/s, inform immediately to your branch o


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ADCPM PC ASSEMBLING

WHAT IS ELECTRONICS?

The word Electronics is derived from electron mechanics, which means the study behavior of an electron under different conditions. The field of science and engineering, deals with electronic devices and their utilization, is called Electronics. An electronic devicdevice in which conduction takes place by the movement of electrons through a vacuumgas tube, or a semiconductor.

ELECTRONIC COMPONENTS:

All electronic circuits contain few basic components. Generally there are only five compothree passive and two active. For example, an integrated circuit (microprocessor) may cthousands of transistors, a few thousand resistors and more on a very small chip. Thnumber of components used in an electronic circuit may be in thousands but each compwill be one of the above five types.

PASSIVE COMPONENTS:

Resistors, capacitors and inductors are called passive components. Basically thesElectrical components. These components are not capable of amplifying or manipulate a However, these components are as important, in any electronic circuit, as an active comp(as transistors). Without using the passive components a transistor cannot amplify the sign RESISTORS:

The flow of charge (current) through any material produces an opposingforce called the resistance (R) of that material. It is measured in ohms, forwhich the (Greek letter omega) is used.

CAPACITORS:A capacitor is meant to store electrons (electrical energy) and release themwhenever desired. Capacitance (C) is the measure of a capacitors ability tostore charge. It is measured in farads (F). However, the unit farad is too large;practically capacitors are used in microfarads (F), or pico-farads (pF).

INDUCTORS:When current flows through a wire that has been coiled, it generates a magnetic field

magnetic field reacts so as to oppose any change in the current. This reaction magnetic field is known as inductance. The component producinginductance is called an inductor. The inductance is measured in henrys (H).

ACTIVE COMPONENTS

There are many active components used in electronic circuits. Active devices or compocan be broadly classified into two categories: tube-type and semiconductor type. Tube dcame prior to the semiconductor devices. Due to their advantages, the semiconductor dare replacing the tube devices in almost all electronic applications. VACUUM TUBES: A vacuum tube is an electronic device made of glass. It has two o

electrodes for the flow of electrons. Flow of electrons depends on the thermal emwhich is achieved by the heating of the filament exists inside the vacuum tube.

SEMICONDUCTOR MATERIALS

Conducting materials are good conductors of electricity. Examples are copper, silver, alumetc. Insulating materials are bad conductors of electricity. Examples are porcelain, glass, qrubber, Bakelite, PVC, etc. The electrical wire consists of a core made of conducting matercopper or aluminum for the flow of current. This core is covered with some insulating msuch as PVC, rubber, cotton, plastic, etc. This covering provides protection against short-cand also against electrical shock hazards.


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ADCPM PC ASSEMBLING

There is one another group of material such as germanium and silicon. These are neitheconductors nor good insulators. At the room temperature these materials have conduclower than the conductors, but much higher than the insulators. For this reason these maare classified as semiconductors.When you raise the temperature of a semiconductor, its resistivity decreases (at temperature, a semiconductor conducts better). The semiconductors have anotheimportant property. The conductivity (resistivity) of a semiconductor can be changed by advery small amount of some specific materials (called impurities) in it.

DIODE: Semiconductor Diode is a two terminal , solid-statedevice. The semiconuctor material (silicon or germanium) is usedin diodes. It has two terminals, one is anode (P) and other iscathode (N). It is a unidirectional device, when diode is in forwardbised state, it allows to flow the current through it and when it is in reverse(negative) biased position, it blocks the flow of current. 1N4001 to1N4007, 1N4148, (Si) BY127, (Ge) are some popularly used diodes.

TRANSISTOR:Transister is a three terminal device, made by the use ofsemiconductor material. It has three terminals, Base, Collector andEmitter. The main current flows between collector and emitter, which can

be controlled by the third terminal (base). It can be used for amplification,switching, etc.. BC547, BC548, AC127, 2N2904 are some popularly usedtransistors.

DIGITAL ELECTRONICS:

Clock: Clock is a timing device located on the motherboard. The system date and time and maintained by it. Apart of this, the main function of the clock is to synchronizprocessing of computer.

Clock Pulse

The clock circuit generates a chain of periodic pulses. These pulses are sent to each unit

computer for controlling of the data movement. Normally the speed of the clock signal high (in MHz to GHz).

BUS: Bus is a group of parallel electric wires used for the data transmission. All the ucomputer system are connected through these buses. The Buses are categorized intotypes according to their usages.

1. Data Bus: A bus, which is used for carrying the data from one unit to another unit, is Data bus. The earlier IBM PC and its successor, the PC/XT, used simple expansion bIts architecture provided an 8-bit data bus (8 wires), which can carry one byte at a time

2. Address Bus: The address bus is used to carry the memory address (location) of the 3. Control Bus: The control bus carries the control signal between the units of compute

transmission of data is controlled by these control signals.LOGIC CIRCUITS

All digital circuits are designed for two-state operation. Input data is converted into binarand processed on the base of some standard logics. This logic system is widely used in electronics (Computer). In this chapter you will learn about the different types of digitacircuits (Gates) together with the symbols and truth tables. Truth Tables describe the opeof the logic gates.

Gates:Gates are the electronic circuits having one or more input signal and one output sig


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ADCPM PC ASSEMBLING

These circuits are used as two-state electronic switch. The switching process is relies ovinput logic (signal) and provides output according to all input values.

NOT gate, AND gate and OR gate are the basic gates. NAND, NOR, Ex-OR and Ex-NORare the secondary gates, can be designed with the help of basic gates. By connecting gates, we can build different circuits to perform desired arithmetical calculations or functions.

Buffers: Buffers do not affect the logical state of a digital signal (i.e. a logic 1 input resul

logic 1 output whereas a logic 0 input results in a logic 0 output). Buffers are normally uprovide extra current drive at the output but can also be used to regularize the logic present at an interface.

NOT Gate: NOT gate has only one input and one output. It works as an Inverter. Inverteused to complement (reverse) the logical state (i.e. a logic 1 input results in a logic 0 outpa logic 0 input results in a logic 1 output). Inverters also provide extra current drive anbuffers, are used in interfacing applications where they provide a means of regularizinglevels present at the input or output of a digital system.

Input Outpu

A Z

0 1

Z = A 1 0

OR Gate: OR gate has two or more inputs and one output. It will produce a logic 1 whenever anyone input is at logic 1. An OR gate will only produce a logic 0 output wheneof its inputs are simultaneously at logic 0.

Input Outp

A B Z

0 0 00 1 1

Z = A + B1 0 1

1 1 1

AND Gate: AND gate has two or more inputs and one output. It will produce a logic 1 outpwhen all inputs are simultaneously at logic 1. Any other input combination results in a loutput.

Input Outp

A B Z

0 0 0

0 1 0

Z = A B1 0 0

1 1 1


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NOR Gate: NOR (NOT-OR) gate has two or more inputs and one output. It will produce a output only when all inputs are simultaneously at logic 0. Any other input combinatioproduce a logic 0 output. A NOR gate, therefore, is simply an OR gate with its output invThe circle shown at the output of the gate denotes this inversion.

Input Outp

A B Z

0 0 10 1 0

Z = A + B1 0 0

1 1 0

NAND Gate: NAND (NOT-AND) gate has two or more inputs and one output. It will prodlogic 0 output only when all inputs are simultaneously at logic 1. Any other input combinatproduce a logic 1 output. A NAND gate, therefore, is nothing more than an AND gate woutput inverted. A circle is again used to indicate inversion.

Input OutpA B Z

0 0 1

0 1 1

Z = A B1 0 1

1 1 0

Ex-OR Gate: Exclusive-OR gate has two or more inputs and one output. It will produce a output when one of the two inputs is at logic 1 and the other is at logic 0. Exclusive-OR

produce a logic 0 output whenever both inputs have the same logical state (when both logic 0 or both are at logic 1).

Input Outp

A B Z

0 0 0

0 1 1

Z = AB + AB1 0 1

1 1 0

Ex-NOR Gate: Exclusive-NOR gate has two or more inputs and one output. It will prodlogic 1 output whenever both inputs have the same logical state (when both are at logic 0 oare at logic 1). Exclusive-NOR gate produces a logic 0 output when one of the two inputlogic 1 and the other is at logic 0.

Z = (A+B) (A+B)Input Outp

A B Z


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ADCPM PC ASSEMBLING

0 0 1

0 1 0

1 0 0

1 1 1

CMO S and its FeaturesCMOSCMOS stands forComplementary MetalOxide Semiconductor is a part of the mothethat maintains system variables in static RAM. In a personal computer (PC), CMOS holbasic instructions the computer needs to initialize its hardware components and boot up. settings are known as the basic input output settings (BIOS),also referred to as CMOS seCMOS controls a variety of functions, including the Power On Self Test (POST). This boot time, so some people disable this feature in the CMOS settings, opting for a quickOnce POST has completed, CMOS runs through its other settings. Many settings cmanually changed within the CMOS configuration screen to improve performance.

BIOS

A BIOS stand for Basic Input/output System is an electronic set of instructions that a comuses to successfully start operating. The BIOS is located on a chip inside the computer designed to protect it from disk failure.

A main function of the BIOS is to give instructions for the power-on self test (POST). Thtest ensures that the computer has all of the necessary parts and functionality needsuccessfully start itself, such as use of memory, a keyboard, and other parts.

CMOS SETUP

When the system is first time power on or reset by user, the system BIOS will enter throutines. During the POWER ON SELF TEST, the following message appears.

Press DEL to enter SETUP

MAIN MENU

CMOS Setup Utility

Standard CMOS Features

Advanced BIOS Features

Advanced Chipset Features

Integrated Peripherals

Power Management Setup

PNP/PCI Configuration

PC Health Status **

Frequency / Voltage Control

Load Optimized Defaults

Set Supervisor Password

Set User Password

Save & Exit Setup

Exit without Saving

ESC : Quit

F10 : Save & Exit Setup, ,,: Select Item

Time, Date, Hard Disk Type ...

To execute the CMOS setup program please press DEL key.

The CMOS setup Main Menu Screen is shown as above.


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ADCPM PC ASSEMBLING

CONTROL KEYS

Keys used in the CMOS setup program are displayed at the bottom of screen.

Arrow Keys: Use the arrow keys to move the cursor to the desired item.

Enter : Select the desired item.

F1: Display the help screen for the selected feature.

ESC: Exit to the previous screen.

PgUp(-)/PgDn(+) : Tomodify or change the content of the highlighted item.

F5: Retrieves the previous value from CMOS data.

(Only the current page setup will be retrieved).

F7: Loads the SETUP default values from BIOS default table

(Only the current page setup will be loaded).

F10: Save all changes to CMOS RAM from the MAIN MENU

DIFFERENCE BETWEEN CMOS and BIOS

CMOS and BIOS are closely related. PCs have a large variety of configuration options, incCPU speed, bus settings, and so on. All of these system variables are stored in the CMOSa small area of very low power RAM.

When a PC starts, the BIOS checks and initializes the PC hardware each times your spowers up or restarts before handing off control to OS (operating system). BIOS code stexecute, and it needs to read the contents of your CMOS RAM to learn how the particularconfigured; the BIOS will not be able to start your PC without valid CMOS RAM contents.

COMMON POST ERROR CODES

Error Code Error Associated with code

1xx System Board Error

201 Memory Error

301 Key Board Error5xx Monitor Error

601 Floppy drive Error

1101 Serial card Error

1701 Hard drive controller Error

Computer Post and Beep Code Troubleshooting

When a computer is first turned on, a diagnostic test called a POST (Power-On Self Test)that checks on-board and attached components in the computer. The POST program sena signal to each device initializing each devices built-in self-test procedure.

The POST-test is a two-stage process, first it will check all of the basic components such system clock, the processor, RAM, the keyboard controller, video card, floppy and hardcontrollers.

When a device fails the first part of the POST, the BIOS will send a series of beeps froPCs speaker (internal) to inform the computer user that there is a problem these beepcoded allowing the user to diagnose the troublesome component. After the video hastested, the BIOS will then indicate any errors encountered by displaying either a numeric c


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ADCPM PC ASSEMBLING

a text message on the screen. When the POST has been completed successfully, the comwill make a short beep to let the user know everything is OK.

The BIOS would issue a beep code specific to the BIOS manufacturer that describes the of the problem. It is important to know what BIOS is on your motherboard. You can detethis by watching the name that flashes in the upper left corner during boot, or by openicase open and looking for the BIOS chip.

IBM BIOS Beep Codes

Beep Status Troubleshooting

One short beep Boot successfully No error has been detected.

Two short beeps Initialization ErrorA problem has occurred initializingmotherboard.

One long one short System Board Error A fault has been detected on the motherb

One long two short Video Adapter ErrorCheck configuration, or replace the adapter board.

One long three short EGA/VGA Adapter ErrorCheck configuration, or replace the

adapter board.

Three long beeps Keyboard Adapter ErrorReplace the keyboard adapter IC or rethe motherboard.

Continue short beeps Power Supply Error Check SMPS Voltages.

Continue long beeps RAM Error Check RAM clean it and insert again

SM PS and its TroubleshootingINTRODUCTION TO SMPS:

CPU is the brain of a PC then a power supply is the heart of the PC. As a human being proper circulation of the blood for the human body to stay alive and working. A computeneed well regulated +5V DC and +I2V DC power supply, for the proper functioning of its vparts. These DC powers are supplied to the computer by the power supply, called [SMPS].

Working of a SMPS

In a SMPS, the main AC supply is first send to a Rectifier, which converts the AC supplyvery high value DC voltage (220). This DC goes to filter section, now the filtered high voltasupply is then given to a switching transistor section. This switching transistor section is swON and OFF at a very high speed by a control section, which generate very high freqsquare wave pulse. The switching transistor section switches the given high voltage DC.

ATX SMPS


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ADCPM PC ASSEMBLING

The square wave pulses are then given to the primary winding of a transformer. These produced a voltage at the primary winding of the transformer, which will generate voltagesecondary winding; the voltage at the secondary winding is then rectified and filtered to prthe required output voltages. The output voltage is also sending back to the switching seThis voltage is first send to a sense amplifier, which compares it with a reference voltaggenerates an error voltage.

ERROR Voltage has Following Functions

1. When there is an increase in the output voltage, the error voltage decrease the ONof the switching transistor, which decrease the output voltage.

2. When there is a decrease in the output voltage, the error voltage increase the Oof the switching transistor, which increase the output voltage.

SMPS Sections and their Components

There are seven sections in a computer power supply

1. Rectifier and Filter section.

2. Switching section

3. Oscillator and Error section.

4. Driver section.

5. POWER GOOD section.

6. PROTECTOR section.

7. OUTPUT voltage section.

Fig. 1.1: Block diagram of a SMPS

1. Rectifier and Filter section components: Fuse, Thermister, Line Filter coil, Surge and Scapacitor, Rectifier Diode, Filter capacitor, SHUNT Resistor.

The main function of fuse in supply is to protect the section from any incominvoltage and protect the supply from short circuit.

Line filter coil is used to stop unwanted AC frequency. Thermister are basically resistor. Their resistance varies with increase in the w

temperature.


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ADCPM PC ASSEMBLING P

One very common reason of the spikes is lighting, which produced powerful jumpssupply voltage.

Surges are generated by the switching OFF a high power motor. Four Rectifier Diodes are responsible to convert 220 VAC into 220 VDC. The DC from Rectifier Diode is not pure. The two-filter capacitors convert it in t

DC.

Two shunt Resistors are mainly responsible to discharge the filter capacitor.

2. Switching section components: Reverse Bias Diode, Switching transistor. For this sdiodes act as an insulator.

Two switching transistor switched here high voltage DC at a very high speedcontrol circuit.

3. Oscillator and error section components: This section uses a 494 IC. It is a 16 pin No I

This IC have inbuilt oscillator and error circuit.

IC oscillator section produce, pulse width modulation [PWM] signals.

Where error circuit compare the error voltage generated by output voltage section.4. Driver section components:Transistors, Driver transformer.

The main function of these components to send the PWM signal to the switching stransistor Base.5. Power Good (PC) section components: This section use a 339 IC. It contains 14 pins

IC has four inbuilt comparator. PG section is mainly use to find any short in motherboany short, found by PG circuit, the computer power supply does not work.

6. Protector components: This section also uses 339 IC. IC comparator No 3 and 4 wprotector section and comparator 1 and 2 works for PG section. Protector section bitself power supply sections.

7. Output voltage section components:SM transformer, Rectifier Diodes. Filter capacit

Induction coil.

SMPS TypesThere are three types of SMPS:

1. XT [Extended Technology]

2. AT [Advance Technology]

3. ATX [Advance Technology Extended]

Note: XT Power Supply now becomes old and not in use. Todays PC use only AT o

Power Supply. Pentium-4 and upper PCs uses only ATX Power Supply.

AT Power Supply

AT power suppliesare used in oldercomputers. ATpower supply wasused with AT casesand ATmotherboards. Thispower supplydelivers 4 voltages, +5V, +12V, -5V and -12V, and uses a 12 pin connector, usually divide


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two six-pin connectors. The problem was that these two six-pin connectors could be inserany side of the 12-pin connector found on the motherboard. In order to avoid mistakes youinstall these connectors in a way that the black wires are placed on the center of the conne

Pin Number Color Function Connector

1 Orange Power Good P8

2 Red (XT No Wire) +5V DC P8

3 Yellow +12V DC P8

4 Blue - 12V DC P8

5 Black Ground P8

6 Black Ground P8

7 Black Ground P9

8 Black Ground P9

9 Black Ground P9

10 Yellow -5V DC P9

11 Red +5V DC P9

12 Red +5V DC P9

ATX Power Supply

You will find ATXpower supplies, invirtually every newcomputer. ATX powersupplies are used with

ATX cases and ATXmotherboards. Thereare three maindifferences between

AT and ATX powersupplies. First, one extra voltage line is available, +3.3V. Second, ATX power supplies single 20-pin connector. And third, this power supply has a power-on wire, allowing the supply to be turned off by software/keyboard.

ATX Power Supply Connections Output Voltages:

Pin Signal Color 2 Color 2 Pin Signal Color I Colo

1 3.3 V Orange Violet 11 3.3 V Orange Viole

2 3.3 V Orange Violet 12 -12 V Blue Blue

3 GND Black Black 13 GND Black Blac

4 +5 V Red Red 14 PS_ON Green Gre



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6 +5 V Red Red 16 GND Black Blac


8 PW_OK Grey Orange 18 -5 V White Whit

9 5V_SB Violet Brown 19 +5 V Red Red

10 12 V Yellow Yellow 20 +5 V Red Red

Comparison between AT and ATX Power Supplies:

AT SMPS ATX SMPS

1. This supply use with 12 pins PCmotherboard.

1. This supply use with 20 pins PCmotherboard.

2. This supply has two same size 6 pinconnectors.

2. This supply has only one 20-pinconnector.

3. This is manual power off supply. 3. This is software off power supply.

Output Voltages

AT SMPS ATX SMPS

Color Voltage Color Voltage

Yellow +12 V DC Yellow +12 V DC

Blue -12 V DC Blue -12 V DC

Red + 5 V DC Red + 5 V DC

White - 5 V DC White - 5 V DC

Black 0V (GND) Black 0V (GND)

Orange + 5 V DC Orange +3.3 V DCGreen PS - ON

Gray PW OK

Purple PW - GD

Pin Wire Color Signal Power Connection

1 Yellow +12V

2 Black Ground

3 Black Ground4 Red +5V

Note:Black wire is ground wire (0V) for all different voltages wires.

Power Supply Connector:

The SMPS connectors are used to provide power supply to the various devices such aROM or Hard Drive etc. This connector is referred to as a large Molex connector.


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Additional to these types of connectors you may also find a smallMolex, which is generally used for the floppy disk drive.

PowerGood:

Main board needs PowerGood signal, when all output voltagesare stable, then PowerGood signal goes to +5V (logical one).

PowerGood signal is usually connected to the RESET signal.

SMPS FAULTS FINDING:

Fault 1: AC fuse BLOWS OFF.Check(A) Switching sections transistor.

(B) Reverse Bias Diode of switching section

(C) Rectifier Diodes.

(D) Filter capacitor [Big size]

Fault 2: Switching transistor blows OFF.Check(A) Rectifier and filter section components.

(B) Switching section Reverse Bias diode.

(C) SM transformer.

(D) 494 IC. Fault 3: PC Restarts Automatically?Check(A) check SMPS output voltages.

(B) If PC receiving AC from any UPS and CVT. Then check the performance of CVT or UP

Fault 4: SMPS output voltages are OK; but SMPS switch OFF after sometimnormal operation?

Check all components of switching section.

Note: To test the computer power supply you must have a digital multi-meter, set the DMDC voltage. First, connect the multi-meter black lead on the Black wire of SMPS, andconnect multi-meter Red lead on different SMPS output voltage wires.

TROUBLESHOOTING THE SMPS: The very first test that should be applied in case a computer stops is to check the

supply. The first step should be checked the supply voltage that is coming to that circuthe power supply. The power supply troubles are easy to select and once it is sure thtrouble in the computer system is related with power supply.

You have to start first checking the output voltages of supply. If all outputs are absentprobably the trouble is in power supply input circuit. In this case, fuse, Diodetransformer and high voltage filter capacitors need to test.

In case if there is no output voltages on any lines then, start checking with Input ACarea. If you find fuse is OK. Then the rectifier diode can be faulty or if rectifier diod

also OK then check the high voltage filter capacitors.

If none of the above methods discussed above helps in removing the trouble in the supply ofyour PC then a step-by-step test with the power supply is recommended.

MON ITOR an d its TROUBLESHO OTINGIntroduction to Monitor

When we use a computer, we need some device to see the results of the work weare Presently our first choice for this is monitor. They are available in many different size and s


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resolution.

A monitor also known as Video Display Terminals (VDT) or Video Display Unit (VDcomputer screen and even some time referred to as Cathode Ray Tube(CRT). It wont fuwithout an appropriate video card, which is a sort of middleman interpreting computer dasending it to the monitor, and which fits inside the computer.

Principle of Monitor

Monitor works on the principle of kinetic energy gained by electrons into light energy. Whe

kinetic energy electrons strike upon the phosphorous-coated screen, then the eneelectrons is utilized by the phosphorous screen in the production of picture information oinside or on it. The main property of phosphorous is that it can start glowing if energy is gby it. In a monitor the electron beam is produced with the help of tungsten filament whinstalled inside the electron gun in the picture tube neck. As the electron beam is producaccelerated with the help of various grids kept at various voltages so the electron beam gvery high kinetic energy due to attraction from these grids and finally this beam strikes upphosphorous screen and the kinetic energy is converted into light energy produced oscreen.

The light energy produced in phosphorous screen is also called luminosity, which is propphosphorous.

Monitor Basic Terms

a. Colour Modes: Monitor are either monochrome or colour.

1. Monochrome Monitor: It provides only two colours to form a picture. TheBlack and White.

2. Colour Monitor: It provides three primary colours to form a picture. Theprimary colours used are RED, Green and Blue by changing the ratio of pcolours we get display with millions of the colours.

b. Types of Display: There are two type of display used for a monitor one is CathodTube (CRT) display and the other is Liquid Crystal Display (LCD).

c. Screen: The monitor are also classified on the basis of the screen, the screen measured diagonally and the variants are available in the size of 4, 10, 12, 1417, 20, 21, inches. The screen is classified as tilted or round type, Full Square(FST) and flatron.

d. Mode of Operation: This depends upon the graphic mode supported by the mThe monitor can be monochrome, Colour Graphic Adaptor (CGA), HGA, PGAVideo Graphics Array (VGA) and SVGA.

e. Interface: It is the hardware or software that forms a link between the deviceallows them to communicate with each other. There are three type of interfaces bya monitor can be attached with a CPU. It can be compositeinterface, 9 pin interface and 15 pin interface.

VIDEO CARD OR DISPLAY CARD

A computer and a monitor cannot connect to each other without any videodisplay card. A display adaptor or a video card is necessary for transferringdata that is to be displayed on the screen, from the processor to monitor.

Video add-on cards are available in three basic groups, the 8-bit, the 16 bit,and 32 bit. These terms refer to the amount of data that can be transferredat one single pass. A 16-bit, card can send data to the monitor in half the


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time required by an 8-bit card.

A video board memory requirement are determined by two things its resolution and the nof colours that it can display. The VGA can display a resolution of 320 x 200 with 256 colouin the higher 640 x 480 resolution. It can only display 16 colours. This has nothing to do wmonitor or the VGA board, except for the amount of memory on board. A normal VGA with 256 KB of memory right on the board. Resolution like 1024 x 768 with 256 colours obvrequires more memory.

Pin Configuration of VGA Adaptor:

Pin No. Signal Direction Description Monochrome Use Colour U

1 > Red Red

2 > Green Monochrome Green

3 > Blue Blue

4 Monitor ID bit-2

5 Ground Self test Self test

6 < Red Return Red Return

7 < Green Return Monochrome Green

8 < Blue Return Blue Return

9 Not used

10 < Sync Return Ground Ground

11 Monitor ID bit-0

12 Monitor ID bit-1

13 > Horizontal Sync Horizontal Sync Horiz. Sync

14 > Vertical Sync Vertical Sync Vertical Syn

15 Reserved

MONITOR TYPES

A. MONOCHROME B. COLOUR

A. Monochrome Type

1. Monochrome

2. Composite monochrome

3. VGA monochromeB. Colour Type

1. Composite

2. RGB

3. ENHANCED RGB [EGA]

4. VGA

Monochrome Type


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Monochrome: Monochrome mean mono means one and chrome indicate cMonochrome monitor show their images in one colour, may be it green, amber, white, crimusesdigital input signals and uses separates lines for its horizontal and vertical synchrosignals and video signal.

Composite Monochrome: This monitor offer lowest resolution of any monochrome sy

This type of monitor can be plugged in to only a CGA.

VGA Monochrome: This monitor will work with VGA display Adaptor. It will display

Graphic without colour.Multi Scanning Monochrome: Other monitors are designed to operate at certainfrequencies. This monitor display adapts to the signals sent to it within a wide ranfrequencies.

Colour Monitor Type

Composite Colour:This kind or monitor connected with VCR or video camera. This comvideo signal standard has long been used with PCs.

RGB: This type of monitor some time called RGBI (Red, Green, Blue, and intensity)

monitors work with CGA, EGA.

EnhancedRGB: (EGA) EGA require a better Quality display one able to handle the 2

horizontal sync frequency of the EGA standard.VGA: This monitor use analog inputs and a 31 kHz horizontal sync frequency to match wit

standard. VGA monitor can display 2, 62, 144 colours.

320 x 200 Resolution = 256 colours

640 x 480 Resolution = 16 colours

VGA is compatible with CGA.

Multi-scanning Colour Display:Multi-scanning monitor do not look their horizontal and vsync frequency to any particular standard. This monitor try to match the synch pulses sthem by PC.

Monochrome Display Adaptor (MDA):The original and simplest display combination

monochrome display adaptor and IBM monochrome display monitor. Monochrome mdisplays clear and attractive character.

Colour Graphics Adaptor (CGA):CGA was introduced by IBM and is used for displayinthe text and the graphics at low resolution as it offer many different type of modes as weexample, a 40 or 80 columns x 25 lines text mode in 16 colours or 640 x 200 pixels gramode in 2 colours or 320 x 200 pixels graphics mode in 4 colours can be selected by thisThis adaptor functions basically in two modes, which are the alphanumeric (A/N), Text, alladdressable (APA) mode and the graphic mode. These adaptors offer 40 column x 25 lithe A/N mode with 16 colours. The character set in both of these two modes is generategroup of 8 x 8, pixels; two resolutions are available in the graphic mode i.e., the av

resolution of 320x 200 pixels in 4 colours or 640 x 200 pixel high resolution in two colourCGA Adaptor can he used with different type of popular branded colour monitors becauhorizontal scanning frequency of CGA board is 15.75KHz.

Enhanced Graphic Adaptor (EGA):This card is similar to CGA with an exemption thatan additional ROM on it and it is used in PC-XT and PC-AT. It has 64 K.B to 256 K.B RAMand ISA 8 bit interface. This card offers 16 colours.

Video Graphics Array (VGA): VGA card offer a much better resolution and more colhigher resolution, in comparison to the video adaptor cards of the earlier kinds. In addi


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many other advanced features over its predecessors. A special type of video chip has beein the VGA card. This too was first introduced by IBM. The chip used on this card hasdesigned by using VLSI (Very Large Scale Integration)

Technology to include a very large number of logic gates within this chip. The VGA adaptoshould be the first choice for interfacing the monitor with the computer. If a monochrome mis used with a VGA card then also the user can receive 16 different shades of grey from BWhite. This can be used to take the advantages of applications that require use of 16 colou

Super Video Graphics Array (SVGA):The super VGA is an improvement over the VGAthe standard set by VESA was that of 800 x 600 resolution and 16 colours. However todayare produced with 256colours and even 1024 x 768 resolution. The problem lies in the nof graphics display modes, the VGA standards itself have 17 different way to display an on the monitor. The number of colours on higher resolution increases in the newer gdisplay standard like the SVGA, IBMs 8514/A adaptor and the Extended Graphics Ad(XGA). The next generation video adaptor using the Continuous Edge Graphics (CEGcan even deliver 7,40,000 colour simultaneously on the monitor. More standard can deresolution as high as 1600 x 1200 and able to generate millions of colours.

First thing to be considered before buying a display adaptor, is the software carrienecessary driver, to make the software function properly with respect to the display ca

have in your computer system.Another factor to be kept in mind is that whether the monitor you have is capable to cathigh resolution being offered by the display card. The older display standard compatible moused the digital interface but the VGA need an analog interface.

The monitor you are having needs to be fully capable to function with the specified horand vertical frequencies specified by the particular graphics display adapter. As VGA bethe accepted next standard, board manufactures first concentrated on building compatibleand then they turned their attention on expanding the capabilities of basic VGA.

Dual Display Adaptor (DDA):These cards are combination of CGA card and HGC [Hegraphic Card]. This Adaptor can output signal for both CGA and HGC compatible monitor

can use this card with a dual frequency monochrome monitor, which can automatically between CGA and HGC based on the signal from dual graphics card.

Changing from CGA to HGC or HGC to CGA can be done by using a special software or jsetting or DIP switches settings on adaptor or by using DOS command mode.

CRT WORKING

The monitor uses a cathode ray tube as the display device. CRT uses an electron gaccelerating anode and a phosphor-coated screen. All are housed in a funnel shaped evacglass shell. The electron gun has a heater, a cathode and a set of grids. The cathodeheated by heater, itreleases the electrons. The CRT has following grids:

1. Control grid, which controls the number of electrons, allowed passing through it.

2. Screen grid which accelerates the electrons passing through the control grid.3. Focus grid which focus the electrons in to a narrow beam.

The beam is made to travel at high velocity towards the CRT screen. The beam strikephosphor coating on the inside of the CRT screen. The phosphor emits visible light electrons narrow beam strikes desired point of screen. The intensity of the emitted light deupon the number of electrons. The colour of the emitted light depends upon the typhosphor.


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The video signals from the computer are amplified by the video amplifier circuit in the mThe characters displayed on the screen are made up of set of Dots called pixels. Thesignals from the computer contain pixels information such as shade and brightness of the the exact location of the pixels on the screen.

Discharging the CRT

Before Removing any wiring or boards from the monitor, it is important that the CRT discharge even though. Unplugging the monitor will prevent AC and high voltage howev

computer monitor operate with exposed voltages. This makes monitor unusually dangerthe hands of inexperienced troubleshooters. Ensure that the monitor is unplugged and aseveral minutes for it to discharge before reaching into the assembly use a screwdriver heavy-duty alligator clip attached between the screwdriver shaft and the metal chassis. rotate the screwdriver or force it in the CRT remember that the CRT is a glass assembly anexcessive force can damage it easily. The assembly should now be safe to work on.

Main Sections of a Monitor are

1. Power Supply Circuit.

2. Horizontal deflection circuit

3. Vertical deflection circuit.

4. Video circuit.5. Synchronization signal processing circuit.

6. High Voltage Generation Circuit.

1. Power Supply Circuit: A switch mode power supply is used to generate the reregulated DC supply voltage for the monitor circuitry.

2. Horizontal Deflection Circuit: This circuit uses a horizontal deflection proces1391, which comprises of a horizontal oscillator in a phase locked loop. The transistor conducts, continuing the deflection of the electron beam to the right centre.

3. Vertical Deflection Circuit: This circuit use a vertical deflection IC [TDA 1170N,

which consist of a vertical oscillator, a vertical fly-back generator and a power amThe output of the POWER amplifier directly drives the vertical deflection coil. The voscillator is set to oscillate at a frequency close to the expected V-sync-frequencgets synchronized with the V-sync pulse from the computer.

4. Video Circuit: The nature and number of video signals from the computer depenthe type of display adaptor in use. In monochrome display adaptor, the video consists of a single TTL positive signal. In case of CGA, three TTL positive signals, Red (R), green (g) and Blue (B) are input to the monitor. The video signabuffered, mixed and then amplified by the video amplifier before being fed to the caof the CRT. In case of colour monitor the output of the R, G and B video amplifier

The respective cathode of the CRT.5. Synchronization Signal Processing: The sync signals (H-sync and V-sync) are levels (+ or -), these signals are buffered and given to the sync input pin respective deflection processing IC. Where the monitor is to automatically between modes a circuitry is provide to sense the polarities and frequency of thesignals and to switch on the appropriate circuit to adjust the height, the free rufrequency of the horizontal oscillator and the horizontal fly-back pulse width fmode.


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6. High Voltage Generation Circuit: This circuit generate the EHT [Around 14 monochrome CRT and 24 kV for colour CRT] required for post-deflection accelerathe electron beam within the CRT as well as the voltages For the CRT grids avideo amplifier supply. These voltages are generated by the EHT transformer comcalled the fly-back transformer (FBT).

The fly-back pulse generated at the collector of the horizontal driver transistor. The primthe fly-back transformer are stepped up by the transformer and rectified by the high v

diode mounted inside the transformer to give the required EHT voltage at the Anode capother grid voltages are either tapped from this high voltage secondary winding or generameans of other secondary winding. These voltages are rectified and applied to the respgrids of CRT.

MONITOR COMMON TYPE FAULTS

Fault 1: No Display?Check: Check power to monitor, brightness control, check cable attached to display adapte

Fault 2: No Picture?

Check: Check power to monitor, Brightness control, check cable attached to display adapte

Fault 3: No raster but LED is Glowing?

Check: Loose connection in power circuit, Brightness control is extreme OFF position. supply voltage is not proper.

Fault 4: Sudden Appearing and disappearing of display?

Check: Weak solder in video circuit, loose contact in CRT base.

Fault 5: Bright spot or line on screen?Check: Monitor cable broken or disconnected, forty monitor deflection circuits, faulty d

adapter (try monitor on another PC).

Fault 6: Only one vertical line appears?Check: Horizontal coil of deflection yoke is defective

Fault 7: Only one horizontal line appears?Check: Vertical deflection yoke short or open, or fault in vertical circuit. Fault 8: SHAKING DISPLAY?Check: Excess ripples in power supply or electromagnetic interference.

Fault 9: Improper height of the display?Check: Vertical height preset misadjusted.

Fault 10: Brightness control not working?Check: Brightness control defective, CRT deterioration, Improper G2 grid voltage, and

voltage.

Fault 11: Black vertical bar on the screen?Check: Abnormal voltage at control grid.

Fault 12: RASTER appears after some time of switching on the system?Check: CRT Deterioration.

Fault 13: Distorted characters on screen?Check: Faulty display adapter.

Fault 14: Noisy Display?


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Check: Grounding problem.

Fault 15: Display Tilted towards one direction?Check: Deflection yoke misadjusted.

Fault 16: Display is upside down?Check: Wires of vertical deflection coil interchanged.

Fault 17: A spot seen when switching off the system.Check: CRT deterioration.

Personal Computers MotherboardsMotherboard is the main component inside the main system unit. This is the biggest eleccircuit board inside the computer system, on which many other boards are attached. The bthat attach to the motherboard are known as daughterboard or expansion board.

The motherboard contains following:

1. Processor Support: The motherboard dictates directly your choice of processor f

in the system.

2. Peripheral Support: The motherboard determines what types of peripherals you ca

in your PC.

3. Performance:The motherboard is a major determining factor in systems performthe motherboard determines what types of processors, memory system buseshard-disk interface speed your system can have, and these components dictate dyour systems performance.

4. Organization: The way that the motherboard is designed and land out dictates h

entire computer is going to be organized.

5. Control: The motherboard contains the chipset and BIOS program, which control m

to data flow within to computer.

6. Communication: All communication between the PC and its peripherals, other PC

user, goes through the motherboard.Intel 4 Processor Family:

Various Cards on the Motherboards motherboard has various cards. Let us now go throuvarious cards and their functioning.

A Display/video card is card in computer whose function is to generate and output imagedisplay. The term is usually used to refer to a separate, dedicated expansion card that is pinto a slot on the computers motherboard. A video card consists of a printed circuit board o


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which the components are mounted. These include:

a. The GPU: It is a microprocessor dedicated to manipulating and rendering graccording to the instructions received from the computers operating system ansoftware being used. At their simplest level, GPUs include functions for maniputwo-dimensional graphics, such as blitting. Modem and more advanced GPUinclude functions for generating and manipulating three dimensional graphics elemrendering objects with shading, lighting, texture mapping and other visual effects.

b. Video Memory: Unlike integrated video controllers, which usually share memory wrest of the computer, most video cards have their own separate onboard mereferred to as video RAM (VRAM). If the video card is integrated in the motherbowill use the computer RAM memory (lower throughput).If it is not integrated, thecard will have its own video memory, which is called Video RAM or VRAM. The capacity of most modem video cards range from 128 to 768 MB. In 2006, the VRAbased on DDR technology standing out DDR2, GDDR3 and GDDR4. The memoryrate is between 400 MHz and 1.6 GHz. a very important element of that managdepth coordinates in 3D graphics.

Type Clock rate (MHz) Bandwidth (GB/s)

DDR 166 950 1.2 -30.4

DDR2 533 - 1000 8.5 - 16

GDDR3 700 1800 5.6 - 54.4

GDDR4 1600 - 2400 64 - 86.4

c. Pin No. Function

1 Red Video

2 Green Video

3 Blue Video4 Monitor ID bit-2

5 Ground

6 Red Return (Ground)

7 Green Return (Ground)

8 Blue Return (Ground)

9 Composite Sync.

10 Sync. Return (Ground)

11 Monitor ID bit-0

12 Monitor ID bit-1

13 Horizontal Sync.

14 Vert. Sync.

15 Reserved


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MOTHERBOARD PROBLEMS

When switched on, if the system produces error beeps or shows error messages.

Check for perfect seating of socketed chips such as Memory chips, SIMM moBIOS and keyboard controller; CPU, etc.

Temporarily remove nonessential cards from the Motherboard.

If the problem is solved, replace cards by ne one and each time check for coperation, this will help to locate the actual faulty device.

If there is intermittent crashing/stopping of system, determine the circumstancecheck whether the crashing of system occurs only when a specific software is exec

Remove unnecessary memory resident programs and device drivers.

Check for various card conflicts like IRQs, input/output ports, DMA channelsmemory locations. Reconfigure in case any such conflict is located.

Remove and reseat expansion cards and interconnecting cables.

Run diagnostic utilities for identifying any hardware problem.

Try reducing the speed of processor or the bus clock.

Card Diagnosis

A useful diagnostic tool is a POST card. PCs send their POST results out on a particuport-most use port 80, while Compaqs may use port 84 and IBMs use 300. The POSTwhich plugs into the ISA bus, decodes these signals and displays them either on a set ofor a seven-segment numeric display. A list of POST codes is needed, and can be usidentify the results being produced by the self-test routine.

If the POST card shows FF, an oscilloscope can be used to see if the processor is accessiBIOS, looking for clock signals, the address and data strobes on the CPU, and for resets.

Diagnosis requires logical reasoning, which in itself requires that the person doing the diaunderstand the system events that are supposed to occur, and in which order.

POST automatically runs when your computer is turned on and tests several components o

PC.The Processor-if the test fails for the CPU, the system stops usually with no error code. RPOST checks the BIOS ROMs. If there is a problem, the system will stop, usually with nocode.

DMA Controller-if there is any problem with the DMA controller, the system will stop.

Interrupt Controller-if POST detects problems with the Interrupt Controller, the system wan audible error signal of one long beep then one short beep then the system stops.

System Timing Chip-this chip provides timing signals for the bus and processor. Any erroproduce an audible error signal of one long beep and one short beep then the system stops

Video Card-if the Video Card fails; there will be one long beep then two short beeps the

system halts.

RAM-any RAM errors will generate a 201:Memory Error message on the screen. Any

codes beginning with 2 indicate a memory error.

Keyboard-a problem with the keyboard will result in a 301:Keyboard Failure error me

followed by a short beep. System may halt / may ignore the error.

Floppy Drives-any problems will result in a 601: Floppy Disk error code appearing

screen.


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Other Devices-POST checks the other ports and components of the computer, beeps, ancontinues. It also checks the Master Boot Record (MBR) on the hard drive. If it cannot fiMBR, it will freeze and not Continue loading, otherwise it hands control over to the MBR (oBoot Record (DBR) if it is booting from a floppy). Summary of POST error codes:

Error Code Problem Description

lxx System Board problem

161 CMOS Battery Failure

164 Memory System Size error

2xx Memory related problem

3xx Keyboard problem

4xx Monochrome video problem

5xx Color video problems

6xx Floppy Disk problem

l7xx Hard disk problem

PCI

The Peripheral Component Interconnect, or PCI Standard (in practice almost ashortened to PCI) specifies a computer bus for attaching peripheral devices to a commotherboard. These devices can take any one of the following forms:

An integrated circuit fitted onto the motherboard itself, called a planar device in thspecification.

An expansion card that fits into a socket.

The PCI bus is common in modem PCs, where it has displaced ISA and VESA Local Bus standard expansion bus, but it also appears in many other computer types. The bu

eventually be succeeded by PCI Express, which is standard in most new computers, andtechnologies.

The PCI specification covers the physical size of the bus (including wire spacing), elecharacteristics, bus timing, and protocols. The specification can be purchased from thSpecial Interest Group (PCISIG).

Chip specification

DDR-200: DDR-SDRAM memory chips specified to operate at 100 MHz



DDR-400: DDR-SDRAM memory chips specified to operate at 200

Chip characteristics

DRAM density: Size of the chip is in megabits. Example: 256 MB, 512 MB chip

DRAM organization. Written in the form of 64M x 4, where 64M is a number of sunits (64 million), x4 (pronounced ) - number of bits per chip, which equnumber of bits per storage unit. There are x4 and x8 DDR chips. The former allouse of advanced error correction features like Chipkill, memory scrubbing anSDDC, while the latter chips are somewhat more expensive.


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SDRAM can be run at lower clock speeds than it was made for (under clocking) or higherspeeds than it was made for (over clocking).

DDR SDRAM DTMMs have 184 pins (as opposed to 168 pins on SDR SDRAM, or, 240 pDDR-2), and can be differentiated from SDRAM DIMMs by the number of notches (DDR Shas one, SDR SDRAM has two). DDR operates at a voltage of 2.5 V, compared to 3.3 V foSDRAM.

Specification standards Chips

Standard name Memory clock I/O Bus clock Data transfers per second

DDR2-400 100 MHz 200 MHz 400 Million





Module

For use in PCs, DDR2 SDRAM is supplied in DEMMs with 240 pins and a single locating DIMMs are identified by their peak transfer capacity (often called bandwidth).

Module name Bus clock Chip type Peak transfer rate

PC2-3200 200 MHz DDR2-400 3.200 GB/s

PC2-4200 266 MHz DDR2-533 4.264 GB/s

PC2-5300 333 MHz DDR2-667 5.336 GB/&

PC2-6400 400 MHz DDR2-800 6.400 GB/s

PC2-8500 (planned) 533 MHz DDR2-1066 8.500 GB/s

Bandwidth is calculated by taking transfers per second and multiplying by eight. This is beDDR2 memory modules transfer data on a bus that is 64 data bits wide, and since a bcomprised of 8 bits, this equates to 8 bytes of data per transfer.

DD3 SDRAM

DDR3 SDRAM or double-data-rate three synchronous dynamic random access memoryname of the new DDR memory standard that is being developed as the successor to SDRAM.

DDR3 SDRAM Components:

Introduction of asynchronous RESET pin

Support of system level flight time compensation On-DIMM Mirror friendly DRAM bailout

Introduction of CWL (CAS Write Latency) per speed bin

On-die 10 calibration engine

READ and WRITE calibration

DDR3 Modules:


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Fly-by command/address/control bus with On-DIMM termination

High precision calibration resistors

Advantages compared to DDR2

Higher bandwidth (up to 1600 MHz)

Performance increase at low power

Longer battery life in laptops

Enhanced low power features and thermal design Disadvantages compared to DDR2

Commonly higher CAS Latency & Lower MFfl3S per Quad Cycle

THE CENTRA L PROCESSING UNITThis chapter presents an overview of the CPU (Central Processing Unit), which functiothe "brain" of the personal computer. Like the human brain, a CPU is a complicated, integrated component performing many simultaneous functions.

MICROPROCESSORS

A microprocessoris an integrated circuit (IC) that contains a complete CPU on a single cthis lesson, we examine the microprocessor from its inception to the current state-of-the-aIt is important for a computer technician to understand the development of the prodifferent from its predecessors.

The CPU

The CPU is the part of a computer in which arithmetic and logical operations are performeinstructions are decoded and executed. The CPU controls the operation of the computerPCs used several chips to handle the task. Some functions are still handled by support which are often referred to collectively as a chip set.

On November 15, 1971, Intel shipped the commercial microprocessor Model 4004. It product called the Busicom calculator. The 108-KHz 4004 had 2300 transistors and a 4-bbus and could address 640 bytes of RAM. Computer engineers quickly took advantage

potential this new type of chip offered, leading the way to the first personal computers.

Microprocessors: Close-up of a CPU

How Microprocessors Work:

Current CPUs, such as the Intel Pentium III, are collections of millions of switches anpathways. They operate all kinds of machines, in addition to PCs, and are found in cam


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cars, microwave ovens, and TVs, among other things. Here, however, we are interested ohow they work inside a PC. Let's look at a simple task : adding two numbers such as 2 together and obtaining their sum (2 + 2 = 4). The CPU can do math problems very quicklyrequires several very quick steps to do it. Knowing how a CPU performs a simple task wyou understand how developments in PC design have improved PC performance.

PC Microprocessor Developments and Features:

PC microprocessor design grows more complex with each generation, and CPU pac

keeps changing to provide room for additional features and operating requiremMicroprocessors have evolved from the 4004 described earlier into today's high-Pentiums. Each new processor has brought higher performance and spawned new technSix basic elements are customarily used to gauge the performance and capability of adesign.

Speed. The maximum number of clock cycles measured in MHz. The higher the speequicker a command will be executed.

Number of transistors. More switches means more computing power. Registers. The size (in bits) of the internal registers. The larger the registers, the

complicated the commands that can be processed in one step.

External data bus. As data bus size increases, so does the amount and complexity o(information) that can be transferred among all devices in the computer. Address bus. The size of the address bus determines the maximum amount of memo

can be addressed by the CPU.

Superscalar Technology:

The main components of a processorregisters, decoders, and ALUsare collectively as the instruction pipeline. To carry out a single instruction, a processor must

Read the instruction Decode the instruction

Fetch operands (for math functions)

Execute the instruction Write back the resultsPentium On-Board Cache:

The original Pentium series came with two 8-KB cachesone for data and one for prcodecompared with the single 8-KB cache on the 486 (16 KB on the DX4). As describethe 486 chip, the cache uses a technique called branch prediction to improve its ability to what data or program code will be required next by the processor.

Intel's Competitors

Competitors have moved away from simply making clones of the Intel processors. Thcurrently designing their own processors with unique features. AMD and Cyrix are amobest known. Until recently, all the Intel processors had been based on a CISC (coinstruction set computing) architecture.

Pentium Pro:

Intel made CPU selection even more complex with the introduction of the Pentium Pro inoffering varied features, in different models, of the Pentium design. This processor was aima 32-bit server and workstation-level applications such as CAD (computer-aided demechanical engineering, and advanced scientific computation.


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Pentium MMX

Soon, more choices were on the way. About the time the 166-MHz Pentiums shippedintroduced MMX (Multimedia Extension) technology, designed to enhance performance ohungry applications like graphics and games. With larger data and code caches, PentiumMMX technology can run non-MMX-enhanced software approximately 10 to 20 percentthan a non-MMX CPU with the same clock speed.

Pentium II

Pentium desktop line ended with the release of the 233-MHz MMX in June 1997.by multimedia was becoming mainstream, and high performance in a graphical user envirowas critical to CPU market success. Intel upped the ante for its competitors in 1997 radical redesign. The first 233-MHz, 7.5-million-transistor, Pentium II processor incorpMMX technology and was packaged with a high-speed cache memory chip Intel relPentium II versions operating at speeds of up to 450 MHz.

Variations on a Theme: The Intel Celeron CPUs

As it had in the past, Intel faced competitors who sold CPUs with similar performance atprices. Most high-priced desktop computers and servers were sold with a Pentium of one another, but home and entry-level PCs were another matter. Enter a variation of th

conceptthe Celeron.Xeon: The Premium Pentium

Intel has labeled a new CPU brand to denote high-end server and high-performance duse. First introduced in June 1998, the Xeon line commands a premium price and offersperformance-enhancing technology. The Pentium II models incorporate 7.5 million transclock speeds to 450 MHz, bus speeds of 100 MHz, full-speed L2 caches in varying sizes uMB, new multiprocessing capabilities, and compatibility with previous Intel microprocgenerations.

Pentium III Processor

The Intel Pentium III processor is the newest member of the P6 family. With 28 transistors, speeds from 450 MHz to 1 GHz, and system bus speeds of 100 to 133 MHzmark a significant jump in PC CPU technology. They employ the same dynamic execution architecture as the Pentium IIa combination of multiple branch prediction, data-flow anand speculative execution.

Inserting a CPU

There are several types of CPU sockets available. Today virtually all desktop PCs comsome variation of the SEC packaging. Other CPUs are generally not worth upgrading anbe one of two common types of package:

Low-insertion-force (LIF) Zero-insertion-force (ZIF)

LIF SocketRemoving an old CPU from an LIF socket is a muscular business! Luckily, there are speciadesigned for this. However, a flat-head screwdriver or a plate cover for an expansion cawill also workjust be sure to pry evenly around the CPU or you will risk damaging the CPsocket, or both.

ZIF Socket:

The ZIF socket, shown in Figure 4.14, was the most popular mount for desktop and towewith 486 and early Pentium CPUs.


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The following table describes the types of ZIF sockets.

CPU Type Pins Pin Layout Vol

486SX/SX2, DXUDX2, DX4ODPR 169 17 17 PGA 5

SX/SX2, DX/DX2, DX4ODPR, Pentium Over Drive 238 19 19 PGA 5

SX/SX2, DX/DX2, DX4ODP, Pentium Over Drive 237 19 19 PGA 5v/

Pentium 60/66 273 21 21 PGA 5Pentium 75/90/100/120 320 37 37 SPGA 3

486 DX4, Pentium Over Drive 235 19 19 PGA 3

Pentium 75-200 321 21 21 SPGA V

Care When Handling a CPU:

Be very careful when handling a CPU or any exposed IC. Static discharge can damage othe chip. Be sure to use a wrist-grounding strap or other approved antistatic device. Takecare to not bend any pins, and make sure the CPU is properly lined up to seat Pin 1 by uscode notch.

SEC Package/Slot 1 Upgrades:

The Pentium II and III series are mostcommonly packaged in an SEC. This package,shown in Figure 4.15, is very simple to workwith. You will need a motherboard mount andmight have to purchase a fan and heat sinkbefore installing the CPU. Check the manual for

jumper-setting adjustments and follow thesimple directions that come with theMotherboard.

Introduction to USB D evices USB (Universal Serial Bus) is a protocol that allows two-waycommunication between peripheral devices and a hostcomputer. It is hot pluggable, allows the device to be connectedand/or removed while the computer is in running mode.

USB Devices

Universal Serial Bus (USB) is a serial bus standard interfacedevices. It was originally designed for computers, but its popularity has prompted it to becommonplace on video game consoles, PDAs, portable DVD and media players, cell ph

and even devices such as televisions, home stereo, digital audio/video players, car stereoportable memory devices.

The Hardware

An USBcable has four wires: power, ground,D+ and D-. The signal wires usually operate indifferential mode. There are two types of USBdevices: high speed and low speed. There are


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differences in the type, length, and connectors that can be used with the two types. Genthe requirements are stricter for high-speed devices. A high-speed device can transfer damaximum of 120 Mbps, while low speed is limited to 12.5Mbps. The PlC 16C745 canoperate at low speed Standard.

The connector at the computer (A End) is a flattened rectangle while at the device (B enconnector is square with two cut-off corners. Each USB device is able to draw 100 mAmpthe cable, which allows a device to be bus powered. A device can negotiate up to 500 m

once connected to the USB cable but this power may not be available. If the powunavailable, the device must stay in a low power setting. Obviously, devices can be poexternally as well.

Term Specification

Created January 1996

Width 1 bits

Number of Devices 127per host

Speed Up to 480 Mbps (USB 2.0)

Port (Type) SerialHot Plugging Yes

External Yes

The Software

When a device is connected, the computer (or a hub) detects the device by a pull-up resipull-up resister on the D- wire signals a low speed device, while a high Speed device has up on the D+ wire. When detected a series of enumeration steps are started. The enumeprocess assigns an identifier number to the device (there can be a maximum of 127 devicenetwork) and also tells the host computer what Sort of capabilities a device has (input, o

etc). The device also informs the computer of its name (Vendor, Product, Version, and Number). If the device identifies itself as a HID (Human Interface Device) then the describes how the data should be interpreted.

USB Hub

A USB hub is a device that allows many USB devices to beconnected to a single USB port on the host computer or anotherhub. USB hubs are often built into equipment normallykeyboards or, more rarely, monitors or printers. Separate USBhubs come in a wide variety of form factors from boxes that looksimilar to a network hub to small designs intended to be pluggeddirectly into the USB port on a computer (that is, without a

connecting cable).

USB devices

1. Mice (Mouse)

2. Key Board

3. Printers

4. Scanners


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5. Digital cameras

6. Webcams

7. Modems Type B Connector

8. Joysticks

9. Video phones

10. Speaker

11. Flight yokes

12. Telephones

13. Network connections

14. Scientific data acquisition devices Type A Connectors

15. Storage devices such as Zip drives

USB Mouse

The USB mouse uses the Universal serial bus interface to communicate with computerWindows and other Operating Systems that support USB interface, USB has become onemost advanced (and one of the best) connections around for mice, printers and peripherals. Installation of USB mouse is quite simple. It is hot swappable, that means, you

not reboot your machine in order to detect for the mice device by the Operating syTherefore, you can plug it in even when your computer is running. The mouse is immerecognized and you can use it right away.

Types of USB Mouse

There are basically three different types of USB mice:

a. The Mechanical Mouse: has a small hard rubber ball underneath that moves atwo rollers as it is passed across a flat surface. Mechanical sensors detemovement of the rollers as an x and y axis and the cursor on screen is accordingly.

b. An Opto-Mechanical Mouse: works on the same principal. The rollers have whe

the end of them with evenly spaced holes. As the wheels spin, a light-sensitive odevice counts the number of holes that pass by and convert those numbers to an y axis.

c. An Optical Mouse: is more accurate or precise and hasno moving parts. It uses a laser to detect movement andhas to be paired with a special pad or mat that has anembedded optical reference grid.

USB Keyboard

USB keyboards are compatible with Windows computers. TheCommand key works as the Windows key, the Option key as the

Alt key, the Help key as the Insert key, and the Clear key as theNum Lock key. The volume keys function as they would on aMacintosh, and the eject key has no function.

The additional function keys placed where the PrintScreen/SysRq, Scroll Lock, and Pause/ Break keys are on mostIBM PC keyboards (F13/F14 through F15/F16) do not work asthose keys in Windows without a special driver.

The USB keyboard can also be used on PlayStation 2 game


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1. USB, Universal Serial Bus, is a protocol that allows two-way communication beperipheral devices and a host computer.

2. An USB cable has four wires: power, ground, D+ and D-.

3. The USB mouse uses the Universal serial bus interface to communicate with comp

4. USB mouses are of three types: Mechanical, Opto-Mechanical, and Optical.

5. USB keyboards are compatible with Windows computers.

6. USB keyboard may hold a hub, so other USB units are connected.

7. The mechanical mouse has a small hard rubber ball underneath that moves againrollers.

8. An Opto-Mechanical mouse works on the same principal; the rollers have wheels end of them with evenly spaced holes.

9. An optical mouse is more accurate or precise and has no moving parts.

10. Data transfer rate (Speed) is higher for USB 2.0, (up to 480 Mbps) in comparison t1.0/1.1.

PC ASSEMBLINGAssembling the PC

After buying all the computer components they must be connected together, this proccalled assembling. Assembling usually takes 20-30 minutes. It must be done carefully tounnecessary damage to the system.

Parts Required for PC Assembling

Following components are necessary before starting.

Processor, Motherboard, Hard Disk, RAM, AT or ATX cabinet, SMPS, Floppy Drive, CDDrive/CD Writer/DVD Writer, Monitor, Keyboard, Mouse, etc..

Cards: display or sound (Not needed if on-board is available on motherboard]

PC Assembling Tool

1. Screwdriver

2. Multi-meter

3. Tweezers

Assembling Precautions

1. First of all, the motherboard has to be fitted at a fixed place inside the PC cabinelocation of Add-On cards and the drivers within the drivers bay of the cabinet cchanged within certain limits. It is better to place them far away from each other; timprove the cooling and reduce the chance of electromagnetic interference bethem.

2. Be sure to handle all the components with great care. If a small thing like a scdropped on the motherboard. It can damage the circuitry.

3. The motherboard contains sensitive parts, which can be easily damaged by electricity. Therefore, the motherboard should remain in its original anti-static envuntil required for installation.

Assembling Procedure

1. Installing Motherboard: You need to determined if the case has the appropriate Rinstalled. Risers keep the motherboard from touching the metal surface of the cas


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it is installed avoiding a short circuit. Keep the cabinet panel on the table and motherboard on it. A gentle pressure is enough to mount the motherboard ON it. will be mechanism to lock the motherboard in place. Now tighten the screws omotherboard to the panel.

2. Installing Processor: Take your CPU now gently lower the CPU in to ZIF sockpressure is required if CPU is placed properly it will slide in to the socket. Make suthe No. 1 pin is placed correctly.

Apply the IC paste that comes with the processor to the bottom of the heat-sink. Only thinis necessary. This lets the heat that is produced in the processor to be conducted to thesink, which cools it. After applying the paste, fix the heat-sink on the processor. Make suthe lock of heat sink is in its place.

3. Installing RAM: Keep the RAM module in the slot in the proper way and downward, be careful not to jerk the Ram while pushing it down see that the lochold of the Ram and stay in the locked position the way of inserting the RAM wwith different kinds of RAM.

4. Installing Floppy Drive: Ensure that one of the bays in your case is open. If youcome with Rails for floppy drive attach them to the sides of the drive and slide theinto the front of the computer until it clicks in to place. When everything line up, the floppy drive in securely on both sides and plug in the power cable. Floppycable are solid ribbon on one end and the other has a small section of the ribbon ctwisted around make sure that floppy cable is attached correctly.

5. Installing Hard Disk: Make sure that the hard disk is set at the master drive on icable. Each IDE cable can support up to two devices. Such as hard disk, CD-drivzip drive, etc. One device designated as a master device and other one mudesignated as a slave device. Look at the top of your hard disk. There should be adepicting the necessary jumper setting to make the drive a master or slave. Nowthe hard disk in to drive tray and screw it from the both sides.

6. Installing CD-ROM: Make sure that at least one bay of computer case is open. Ex

the jumper settings on the top of the drive as we did with hard disk. Ensure that theis set to slave. If it is attached on the IDE cable that already have connected a hardattach power cable to the drive the Hard Disk and CD-ROM power and IDE cablebe connected in such way that the red cables of both plugs with come togetherconnect the sound cable of the CD-ROM to the sound card so that the audio CDwork properly.

7. Attaching Power Supply: There are two kinds of motherboard available in mThey have different SMPS connectors (AT and ATX). Identify the type of Power that is used by your motherboard. AT Power Supply, cable must be connected in way that the Black cables of both plugs with come together.

8. Installing Expansion Cards: Insert your video card, if it is not onboard. Thepresently about three different forms of slots on motherboard PCI, ISA and AGP. card are made for all of them AGP slots more than likely is the small brown, slotmotherboard PCI probably have the most of these their white and little longer thanISA these are long and black.

9. Connections: Now fix the cables that are provided to the necessary place omotherboard. Be careful to fix the cable properly and not damaging the pins. Makthat the Red part of the IDE cable is in proper position.


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Name Of Cables Devices

IDE Hard-Disk, CD-ROM

Floppy Floppy drive

Power SMPS to motherboard

Front Panel Display Speaker, HDD & Power LED, Reset & Power Switch

Backside PS/USB, LPT, COM, CD-ROM, audio cableCard Connectors Onboard display to backside cable

Pins Configuration on Motherboard.

Device Name No. of Pins

LPT 25

COM 09

IDE 40

FLOPPY 34

Connection in the Cabinet:

Connect the wire is coming out from behind the face of computer, case to motherboardcontrol the ON, OFF, Reset, hard disk activity and power switch. During connecting wimotherboard, see the following indications:

Indication Connector wire

SPK Speaker

HL/HDD Hard drive LED

RST RESET Switch

PS POWER supply

PWR POWER LED

Connecting Other Peripherals

Plug the data cable of the monitor to the display card. It will be marked on the back of caConnect keyboard, speaker, and mouse to the back of cabinet in the correct place.

Powering the System

Press the power button of the Cabinet, if everything is connected properly, as it shouldsystem fans should start spinning.

You will hear a single short beep and after about 2-5 second, the computers start to boot.

At the first screen, press the DELETE key to enter the BIOS setup. Review the BIOS settin

a. Time and Date

b. IDE device and floppy

c. Booting Sequence

Depending on the manufacture of the motherboard, you may get an H screen or just a mcheck. Your system will now halt with an error because we have not installed an opesystem.


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If there is no trouble, the system is ready. Now the operating system can be installed.

Testing an Assembled PC

1. You press Power Button and nothing happened.

May be the power cable not plugged in. Check the switch at the back of the case. Makthat you connected the wire from the case power button to the right connector omotherboard. Check the floppy power cable, if everything is OK then next stops to ueverything from the motherboard with the exception of the power cable, power button

memory, and CPU. If it still not powering up, it is likely that you have at least one defcomponent.

2. System turns ON, and produces long Beeps, does not boot up.

Check that your memory (RAM) is installed correctly. Remove it and insert again.

3. Your system hangs while installing operating system.

It could be a heat issue, especially with AMD processor. Check, that heat sink fan is spand that the heat sink itself firmly mounted to the surface of the processor.

4. When Installing Operating System Error occurs in copying files and display Blue sc

Error while copying the setup files are a common indicator of problem of RAM. It is pothat would also be a hard drive problem but if you are getting Blue screens especial

one indicating that a PAGE fault has occurred. It is time to replace the RAM.

DISASSEMBLING THE C OMPUTERPre-Requisites

Have a container to keep the screws.

Make sure you have the tools that you need disassembling.

Make sure you have all the required material, drivers, and software that you may n

Before disassembly do a full backup of the system.

Close all programs, shut down Windows, and turn off your computer.

Switch off power supply then remove all the cables from the back/front.

Opening the Cabinet

Now you need to open the computer case. Some computer cases slide off very easily, buthave 4-6 screws on the back of the case. If your computer case has screws, carefully takeout. After all the screws are off, carefully open the case and place it in a safe place.

Removing Adapter Cards

Now you can take out your adapter cards. These adapter cards are like your soundgraphics card, network card, internal modern etc. take out the card screw first, after takithe screw, then pull the adapter card and store the card in an antistatic bag.

Removing DrivesNow you need to take out the CD/DVD drive and your hard drive. This should be quiebecause there are only two wires attached to both of them. One is the IDE cable and the othe power cable. After taking out the wires, carefully open the screws of the drives. Note thscrews are on both sides.

Removing the Memory

RAM (Random Access Memory) are small cards, there are two pads, one on each side of e


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RAM slot. Make sure you open the pads before pulling the RAM out. After opening the padout the RAM very carefully.

Removing the SMPS (Switch Mode Power Supply)

Remove power connectors to the motherboard and any auxiliary fans. AT Power Suppliestwo-piece power connectors that may be labeled P-8 and P-9. The black wires should bemiddle (black to black) and ATX power supply has only one connector with side lock. Rthe connections from the front-panel power switch of the case before removing AT power s

ATX power switch is directly attached with motherboard. After this remove the four screwsback of the case and gently slide the power supply out of the case. While removing screws, hold onto the power supply with utmost care.

Removing the Motherboard

Remove all wire attachments to the motherboard there are usually 2-3 screws and plastholding down motherboards. Make sure you have the right ones and remove Motherboards sit on plastic or brass standoffs that keep the traces and solder from touchimetal case and grounding out. Once the screws are removed, you can lift the motherboaIn other cases, the motherboard has to be slid horizontally towards the bottom of the cunclip the plastic standoffs and then lifted out. Place the motherboard in an antistatic bavoid any harm to the motherboard.

COMPUTER CONN ECTORS AND INTERFACEUSB Connectors:

USB (Universal Serial Bus) designed to connect USB compatible devices. The Universal Bus is host controlled and there can be only one host per bus. An USB system consists of controller and multiple devices connected in a tree-like fashion using special hub devicesmay be cascaded, up to 5 levels. Upton 127 devices may be connected to a singlecontroller.

Type A: Type A ports and connectors are small and rectangular and are typically used to device into a Type A USB port on a computer or a hub. Type A ports and connectosometimes referred to as upstream.

Type B: Type B ports and connectors are small and square and are used to attach acable to a USB device. Type B ports and connectors are sometimes referred downstream.

Pin Signal I/O Definition

1234

+5-DATA

+DATAGND

N/AL/O1/0N/A

Supply voltageDifferential dataDifferential dataSignal ground


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Keyboard and Mouse Connectors

The system uses a Personal System/2 (PS/2)-style keyboard and mouse. Cables fromdevices attach to 6-pin, miniature Deutsche Industry Norm (DIN) connectors on the backof your computer.

Pin Signal I/O Definition Connector

1 KB DATA T/O Keyboard/Mouse data

2 NC N/A No connection

3 GND N/A Signal ground

4 F VCC N/ A Fused supply voltage

5 KB CLK I/O Keyboard/Mouse clock


Parallel Connectors

The integrated parallel port uses a 25-pin D-subminiature connector on the computerspanel. This I/O port sends data in parallel format (where eight data bits, or one byte, ar

simultaneously over eight separate lines in a single cable). The parallel port is used primaprinters.

Pin Signal I/O Port Definition Connector

1 STB# I/O Strobe

2 PD0 I/O Printer data bit 0








10 ACK# I Acknowledge

11 BUSY I Busy

12 PE I Paper end

13 SLCT I Select14 AFD# O Automatic feed

15 ERR# I Error

16 INIT# O Initialize Printer

17 SLIN# O Select in

18-25 GND N/A Signal ground


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Serial Connectors

The two integrated serial ports use 9- pin D- subminiature connectors on the back panel. ports support devices such as external modems, mouse, plotters, and mice that requiredata transmission (the transmission of data one bit at a time over one line).

Pin Signal I/O Port Definition Connector

1 DCD I Data carrier detect

2 SIN I Serial input

3 SOUT O Serial output

4 DTR O Data terminal ready

5 GND N/A Signal ground

6 DSR I Data set ready

7 RTS O Request to send

8 CTS I Clear to send

9 RI I Ring indicator

Video Connector

The system uses a 15-pin high-density D-subminiature connector on the back panel for atta video graphics array (VGA)-compatible monitor to your computer. The video circuitry system board synchronizes the signals that drive the red, green, and blue electron guns monitor.

Pin Signal I/O Definition Connector

1 RED O Red video

2 GREEN O Green video

3 BLUE O Blue video


5-8,10 GND N/A Signal ground

9 VCC N/A VCC


12 DDC data out O Monitor detect data

13 HSYNC O Horizontal synchronization

14 VSYNC O Vertical synchronization

Network Interface Controller

The MC provides all the functions of a separate network expansion card and supports bo10BASE-T and 100BASE-TX Ethernet standards.

Your system has an integrated 10/100-Mbps NIC.


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UPS OVERVIEWUPS (Uninterruptible Power Supply) is basically an electronic device. That provides backup and safeguard to the computer against unacceptable voltage level, power fluctusags, or surges. When the main power supply interrupted then UPS uses backup batteriehas an automatic controller that ensures continuous supply.

The UPS converts the direct current (DC) battery voltage into the alternating currenvoltage required by the computer system. It can be used to save your current work

computer and close down, after a set number of minutes, and so protect the computer adata. There are many different types of UPS implemented in different ways according requirements of the devices that they are supplying with power.

UPS TYPES

Off-line UPS On-line UPSOff-line (Standby) UPS

Off-line UPS are the simplest and least expensive. In offline UPS, the AC line is the ppower source, when AC power drop UPS switches over to the backup battery automaWhen AC power is restored, the UPS switches back. The switching from mains to battery generally referred to, as Transfer Time usually takes no more than four milliseconds, whil

it is possible for the UPS to not make the switch fast enough for the PCs power supcontinue operation uninterrupted.

On-line (True) UPS

On-line UPS are more complex and costly more than off-line UPS. On-line UPS is also knodouble conversion, or continuous, this is a top-end UPS, which operates with the battery bunit as the primary power source, rather than the secondary source. The big advantage power comes via the battery, which is constantly being charged. The double-conversion

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