LESSON-1
FRONT AND BACK SIDE OF COMPUTER
Front side Computer
Back Side Computer
Back side

SMPS: Switch Mode Power Supply is used to supply necessary power to various components of Computer. It has one
Input Socket for 220V AC and converts this AC Voltage to various DC Voltages.There are two types of SMPS. One is
AT and the other is ATX.

SMPS FAN : This is inbuilt in SMPS . It is used to exhaust excess heat from SMPS.

Power In: Socket to input 220V AC.

PS-2 Port: It is a 6-pin round shaped connector used to connect keyboard or Mouse. Colour Coding defines the
connector type. Purple connector is for Keyboard and Green colour used for Mouse.

USB Port. Often known as Universal Serial Bus used to connect various input and Output Devices like
Mouse,Keyboard,
Printers, Webcams etc. USB 2.0 and Newer version USB 3.0 are available.

DVI Port: Digital Video Interface is high speed serial link for connecting output display Devices.

HDMI Port: High Definition Multimedia Interface is used to get high resolution video and good uality digital sound.The
output device must also be HDMI compatible to output these signals.

15-pin Female VGA Port: This is used to connect Monitor / LCD / LED Dsiplay.

LAN PORT: used for Networking.

Audio Ports: used to connect MIC , LINE IN and SPEAKERS. Colour standards are generally followed.Green is for
Speakers or Headphones. Pink is for Microphone and Blue is used for Line-In.

Expansion Slots: Used to connect add-on cards for having extra features on motherboard.
Front Side

DVD-Writer: Top space is reserved for CD-rom or DVD-writer.

Power-LED: The LED glows and indicates that the Input Power is ON

HDD LED: When we are working on computer, the hard disk is in use , this LED glows and is the indication for hard disk drive is
working.

Reset Switch: This is uite handy when the computer is stuck-up and you are not able to work on computer . Just press this switch,
the computer will Re-Boot.

Front USB: Cabinet provides facility for you to connect USB devices from front-side as it is uite cumbersome to get to back side of
computer again and again.

Front Audio Ports: The ports for MIC and HeadPhone for user easiness.

Power Switch: Used to switch on the computer.
LESSON-2
MotherBoard
Motherboard as the name suggests is the mother of all components of computer.It has different names like System Board
or Main Board. Mother boards come in lots of Configuration and types. I have tried to cover almost all Basic types starting
from early 90's till date.
Different Series of motherboards:
1. Expansion Slots: Also called I/O Bus Slots are used to connect add-on cards like Graphics card,Lan cards,TV out
cards etc.All the cards are connected in parallel i.e any card can be inserted an any of the slots.Types of slots are:
a) ISA slots: ISA means Industry Standard Architect.They are Black in colour, 98-pin connectors. The slots supported16bit data path.ISA slots were available in 286/386/486-motherboards.
b)PCI slots: PCI means Peripheral Component Interface. They are white in colour , PCI slots supported 64-bit data path
that means data now travels much faster than ISA slots.PCI slots were available from 486/pentium series computers.
2.Memory Slots: The slots hold memory (RAM) modules.Different memory slots are:
a)SIMM slots: Single Inline Memory Modules SIMMs come in 30-pin and 72-pin formats.These slots were available upto
386 boards.
b) DIMM slots: Double Inline Memory Modules.They come in different pin formats starting from 100 pin.Dimm slots
started from pentium series motherboards.
3.Processor Socket: This is the area where you insert your processor.There are diffrent type of sockets for different
type of processors. Some of the Socket types are:
Socket Type
No. of Pins
Supported Processors
Socket 7
321
AMD K5 / K6 / K6-2 / K6-III
Cyrix MII ,Intel Pentium, Pentium MMX
Socket 370
370
Intel Celeron Intel Pentium III VIA C3
Socket 775
775
Intel Celeron, Intel Dual-Core , Intel Core 2
Duo , Intel Core 2 Quad Core Intel Pentium
4
Intel Xeon
Socket 1156
1156
Intel Celeron Dual-Core Intel Core i3
Intel Core i5 ,Intel Core i7 ,Intel Pentium
Dual-Core , Intel Xeon
Socket 1366
1366
Core i-7 900 series
4.BIOS ROM: Acronym for Basic Input Output System . A permanent memory chip that contains all the basic information
about motherboard like display chip , ports and other functions.You can change the BIOS settings by entering BIOS of
motherboard for optimum use.
5. CMOS Cell: This is a 3.0 DC volt Battery cell responsible for backing up voltage supply to BIOS .It is this cell which
keeps your date and Time up to date.
6. Power Connector: The connector where the motherboard gets the input DC supply from SMPS.
a) AT connector: Available in older motherboards upto 486-supported-boards
This is a 12-pin( 2 x 6pin) connector. Commonly called as P8 and P9 connectors
b) ATX connector: Available on all currently available motherboards.ATX connection comes in 20 pin and 24 pin
connector.
7. IDE connector: IDE means Integerated Drive Electronics which is a standard for Disk Inerface.
a) 40-pin connector: This is used to connect Hard Disk Drive. A IDE 40 pin Cable is used as a interface to connect hard
disk to motherboard. A maximum of two hard disks can be attached on a single IDE port.
b) 34-pin connector: This is used to connect Floppy Disk Drive. A IDE 34 pin Cable is used as a interface to connect
hard disk to motherboard.A maximum of two Floppy Disk Drives can be attached on a single IDE port.
8.SATA connector: "Serial Advanced Technology Attachment," or "Serial ATA." is used to connect hard disk drives to
motherboard. The SATA cable has 7 pins and transfers the data at a much better speed as compared to 40-pin cables
which work on "Parallel ATA" technology.
9.Co-Processor: A processor which is factory mounted on the motherboard. It helps main CPU in shouldering the
responsibilities or functions of main processor.It accelerated the performance of computer by offloading some of the tasks
of main processor.
10. Cabinet Connections: The Cabinet , we use, has many connectors of its own to be connected on motherboard like:

Power button

Reset Button

Hard Disk LED

Power ON LED

Front Audio Jack

Front USB Jack
11. I/O interface connectors
LESSON-3
Add On Cards
The Cards inserted in Expansion Slots ( PCI , ISA or AGP) of motherboard are called Add-on-Cards. Different types of
cards are;

Display Cards

TV out Cards

Lan Cards

Communication Cards

Modems

Sound Card
We will discuss here only Display Cards.
The Video Cards have 9pin D type Female connector or 15 pin D type Female connector.
The hirarchy of cards starting from older ones is:
1. MDA => Monochrome Display Adaptor
2. CGP => Colour Graphic adaptor with printer port
3. MCGP => MultiSync Colour Graphic adaptor with printer port
4. EGP => Enhanced Graphics adaptor with printer Port
5. VGA => Video Graphics Array
6. SVGA => Super Video Graphics Array
7. AGP => Accelerated Graphics Port
Card Type
Connector Type
Video RAM
Bus
MDA
RCA similar to audio in
8 Kb
8 bit
pin
CGP
9 pin D type Female
16 Kb
8 bit
MCGP
9 pin D type Female
64 Kb
8 bit
EGP
9 pin D type Female
256 Kb
8 bit
VGA
15 pin D type Female
Max 512 Kb
16 bit
SVGA
15 pin D type Female
1 Mb & Above
16 bit
AGP
15 pin D type Female
128mb & above
64 bit
All the above cards are used ISA slots , PCI slots or AGP slots on Motherboard.
Now 'a' days almost all the motherboards have integrated display cards also called on-board graphics.To further enhance
the video quality and speed, we can use PCI Express or AGP diplay cards.These cards have been designed and
maufactured for very high end graphics applications or games.
LESSON-4
Memory
Computer Memory is of two types:
1. Permanent memory
2. Temporary Memory
Permanent Memory : The memory that stores data permanently and is non-volatile (means memory contents are not
erased when power is switched off). Physically it is present on the Motherboard in chip form and is called ROM / EPROM
/ EEPROM.
Functions of ROM :

Code Conversion ( e.g Video Code to Electrical Signal)

POST =>Power On Self Test

BIOS =>Basic Input Output System, generates codes like ASCII codes

BASIC =>Beginers All Purpose Symbolic Instruction Code , Gives English Like Statements by converting codes
generated by BIOS.
Temporary Memory: This memory is Volatile( erased when power is switched off) . It is physically present on
motherboard in the form of :
RAM Modules:
Different Type of RAM modules are shown above. You can differentiate these RAM modules by the CUTS on golden pins
on lower side of each module Just notice that each type of RAM module has cut on different postions along the
length.RAM modules have been aligned vertically according to thier date of origin and speed. Like SIMM modules were
among the first type of memories to come and DDR 3 are the fatest and latest memory types.All the above type of RAM's
are Dynamic RAM's.
RAM is further classified as two types
1. DRAM:Dynamic RAM
2. SRAM: Static RAM
DRAM
SRAM
Memory Cells Type Capacitors
FET
Packing Density
High
Low
Speed
Low
High
Cost
Less
High
Function ( Used As Main Memory
)
Cache Memory
Cache Memory :
When the processor needs to read from or write to a location in main memory, it first checks whether a copy of that data
is in the cache. If so, the processor immediately reads from or writes to the cache, which is much faster than reading from
or writing to RAM .
Shadow Ram :
Speed wise ROM is slower device as compared to RAM
Shadow RAM is copy of ROM(BIOS) into RAM. It is copied at the time of Boot-up and while working, system works on
shadow instead of ROM. As RAM is faster than ROM , the speed of execution is increased. Shadow RAM can be disabled
or enabled fromBIOS settings.
LESSON-5
SMPS
SMPS: means Switch Mode Power Supply, they are Digital in Nature.They step down voltage by "switching" it on and off,
hence their name.
SMPS converts AC Voltage to DC voltage. All the computer parts work on DC supply.SMPS supplies DC voltage through
connectors on Motherboard and various other devices.
As you can see back side of SMPS. FAN is used to dissipate/reduce the heat generated in SMPS. In Fig , there are two
AC power sockets. One is for AC 220 V input to SMPS and the other is for output AC 220 V to your Monitor/LCD. In some
SMPS there is only one socket for AC 220 V input to SMPS . In this case the monitor will take input supply directly from
other power source.
DC output Connectors for Motherboard.
ATX 24-pin power connector 4-pin connector FDD connector
ATX 12V connector SATA power connector
In following Figure, there are two 6-pin connectors. SMPS with these type of connectors is called AT Power Supply. This
supply was used on older motherboards supporting upto 486 processors.Colour coding and the related DC voltages are:
Wire
DC
Colour
Voltage
Red
+5V
White
-5V
Black
Ground or
0V
Blue
-12V
Yellow
+12V
Orange
+ 5V ( PG)
The last voltage +5V, PG here means Power Good. which means If +5V is coming in orange wire, the health of other
voltages is correct.
ATX here means Advanced Technology extended.It has 20-pin/24-pin or/and 4-pin 12V output connector. In newer ATX
boards you have to use these supplies. The cable wire colours and thier corrosponding voltages are as follows:
Wire colour
DC Voltage
Red
+5 V
Yellow
+12V
Black
Ground
Blue
-12V
Grey
Power Good
Green
Power On
Purple
+5V
StandBy
Orange
+3.3V
Brown/Orange +3.3V Sense
White
-5V
(optional)
Note: To switch On or Test the ATX supply before installing on the motherboard , insert a wire between green and black
wire to short them.
4 pin connectors :
The wire colours and thier voltages are:
Wire
DC
Colour
Voltage
Yellow
+12 V
Black
GND
Black
GND
Red
+5V
Used For
Motors
Logic
circuit
The 4-pin connectors are used to give supply to various devices like Hard Disk Drives , CD-Drives , Floppy Disk Drives
etc.
LESSON-6
Hard Disk Drive
One of the important part of computer, since it contains your valuable data. HDD is a permananet storage device.
Sizes
1. 3.5" for Desktop Computers
2. 2.5" for Laptops
Capacity: The Hard disk come in various capacities starting from 10mb(older versions) to 2Tb( TeraBytes).
Interfaces:

40 pin IDE male connector on motherboard

50 pin SCSI connector

SATA connector

USB connector
Hard Disk Geometry: Data is stored on disks (platters in case of HDD) in bytes.The bytes are further organized into
sectors.Sectors are grouped together into tracks and tracks are arranged into groups called cylinders.
If we compare hard disk with floppy disk, a hard disk is metal disk called platter. Unlike floppy disk drive which has only
one disk(platter in case of hdd), hard disk can have any number of platters depending upon the storage capacity of hard
disk.
Like Floppy Disk, hard disk also conatins heads on both side of platter to read or write data.If for example hard disk has
two platters, the number of heads will be 4.In hard disk you cannot align or clean the heads manually since hard disk drive
is closed air-tight enclosure.
Warning : Do not open hard disk yourself as it can damage the drive. It should be opened strickly in air-tight room by
professionals. We have opened a faulty hard disk drive to show you the platter.
LESSON-7
Assembling New Computer
Now you are well conversed with computer components. Let us assemble a computer. First step is to gather all the parts ,
lets make a list of parts needed
1. Cabinet ( comes with pre-fitted SMPS)
2. MotherBoard
3. Processor(CPU)
4. RAM
5. Hard disk Drive
6. DVD Writer
7. KeyBoard
8. Mouse
9. LED Displa
10. UPS

Step One : Installing a processor on MotherBoard
Take a processor. Let it be any make or series , the basic and first thing to notice is the cut or notch on processor as well
on CPU socket on the motherboard. You have just to match both the cuts and close the clip or lever.
Cuts/notches as on PIN-less processor types
Cuts/notches as on pin-type processors

Step two : Put a FAN on processor . Since all the processing and calculations is done by CPU , it gets heated up in
seconds. To dissipate heat we have to put a FAN fitted on Heat-sink on it. You can also apply some Heat-SinkCompound on processor before fitting heatsink cum fan .We will show you two most common type of FAN fittings
1. Side-Clips Type
2. Push Pin-Type : There are four numbers of PINS on corners of Fan. Make sure they are fully rotated clockwise before
fitting. The other thing you have to take care of is always fix the pins onto motherboard in diaganol direction. If you have
fixed pin no 1 on board then the next pin to be fixed on board will be No 3 then pin no 2 and then Pin no 4.
As you can see Fan Pins will go into the holes( dedicated for fan) on motherboard

Step three: Giving power supply to FAN.
There is 3 or 4 pin male connector on motherboard as shown in Fig below. Connect power cable from fan to this
connector.

Step four : Fitting Motherboard in Cabinet.
As you can see there are already grooves or holes for screws in cabinet to fix a motherboard. Match the Holes on your
motherboard wih holes on Motherboard. But before fixing board , Fix a interface strip on the cabinet that comes with
motherboard since every Motherboard has its own set of layout of connectors. Fig below shows strip and its fixing on
motherboard.
Blank Cabinet
Brass-hole-headed screws where motherboard will fit
Interface Strip ( comes bundled with motherboard)
Push the strip towards outward as shown
Followng pictures shows fixing of Motherboard on Cabinet :
Outer view of interface strip

Step Five: Fixing RAM . This is one of the easiest part to fix. Just pull both plastic locks outwards , Put RAM in slot ,
press the ram onto slot , the locks will be automatically fixed.
Just align the RAM according to the cuts shown on RAM and RAM-slots and PRESS it.

Step Six : Fixing SMPS.

Step Seven: Fitting and connecting Hard Disk Drive.
Special space of size 3.5" is assigned in the cabinet for fitting HDD . you just have to tighten the screws (provided along
with Cabinet). Please fix all the 4 screws , the hdd should not be loose when the computer is running. Since hdd has
media rotating in it with the heads reading data , any physical vibrations while running can damage the HDD.
Fixing cables on SATA HDD:
Slide the HDD into the bay
Install the screws on both sides
sata cable connected between hdd and motherboard
Now install SATA power connector
difference between SATA power connector and IDE power connector

Step Eight: Fitting DVD Writer in cabinet. On the top section of the cabinet there is a 5.25" space to fit DVD Writer.
Gently Slide the DVD Writer into this slot from the front side. Simply tight the screws on both sides .
Interface can be IDE or SATA just like HDD.
Installing other peripheral devices.( ATA or SATA):
Important TIP : If you don't want to look for cuts JUST make sure the RED colour of both sides of cables are on the inner
side.

Step nine: Fixing SMPS cables on motherboard .
Fix AT(12-pin) or ATX power connector (20 pin/24-pin + 4 pin 12V connector) on motherboard as shown in Fig.
All the connectors are designed in a way that they can't be inserted in wrong direction.
Installing AT 12 pin connector : The only and most important instruction here is that Make sure the black wires of both 6pin connectors( also called P8 and P9 connectors) are on inner-side and side-by-side.
FIG AT connector
Installing ATX (24pin)connector:
Installing ATX (4-pin) connector: The extra 4-pin connector was introduced for load-balancing of 12 V supply line because
of the needs of newer motherboards.

Step Ten Installing Cabinet connectors: Every Cabinet has various buttons like power button,Reset button,Power
LED, HDD LED and accessory ports like front USB option, Front sound ports.
They are simple wire-cables which you have to connect on motherboard based on Legend Printing on motherboard.
Installation of Front-USB connector ---see the hole blocked on connector and correspondigly see no pin on motherboard.

Step Eleven: Now you have assembled the computer , last step is to close the side cover and install the screw.

Step Twelve : Checking Display. This is an effective way to check whether you have assmbled the computer in right
manner.
1. Connect 15-pin VGA connector of your Display unit( CRT monitor/LCD Display/LED Display) to 15-pin female connector
on the back side of computer.
2. Connect power cable to smps part of computer.
3. Connect Keyboard and mouse to USB ports.
4. Last but important connect your computer to UPS(Un-interrupted Power Supply).It is very important to safegaurd your
expensive computer from impure or interrupted power supply.
HERE YOU ARE: You have just completed the body part, A human BODY is of no use without SOUL or a car-body is of
no use , to run a car you need an engine similarly for a computer to run , you have to install operating system in it. We will
discuss and let you know all the steps needed to install an operating system.