Experiment No. 09
AIM: To study various internal and external hardware components of computer architecture
and its organization.
COMPONENTS/TOOLS: Computer with front, real panel connection, CD drive, USB, audio etc.
THEORY:
A computer is a device that transforms data into meaningful information. It processes the
input according to the set of instructions provided to it by the user and gives the desired
output. This experiment examines the fundamental organization and operations of a
computer system. As a student, you should know and be able to identify the components
found in a typical computer (PC) system. As shown in Figure 9.1, the PC is modular by design.
It is called a system because it includes all the components required to have a functional
computer. A peripheral is a piece of computer hardware that is added to a computer in order
to expand its abilities. The term peripheral is used to describe those devices that are optional
in nature, as opposed to hardware that is either demanded or always required in principle.
There are all different kinds of peripherals you can add to your computer. The main distinction
among peripherals is the way they are connected to your computer; it can be connected
internally or externally.
Figure 9.1 External Parts of Computer System
68
Experiment No. 09
Components:
1. Tower Case: A computer case, also known as a computer chassis, is the enclosure that
contains most of the hardware of a personal computer. The Figure 9.2 shows the tower
case.
Figure 9.2 Schematic of Tower Case

Reset Switch: Supporting the reset function requires, a momentary-contact switch that
is normally open. When the switch is closed, the board resets and runs POST.
 Power Switch: Supporting the power on/off function requires, a momentary-contact
switch that is normally open. The switch should maintain contact for at least 50 ms to
signal the power supply to switch on or off.
 Drive bays: Drive bays are most commonly used to store disk drives, although they can
also be used for front-end USB ports, I/O bays, card readers, fans, tool storage, and
other uses. 3.5" - 3.5" bays, their actual dimensions are 4" wide by 1" high. Those with
an opening in the front of the case are generally used for floppy or Zip drives.
2. Front Side Connecters: Front panel connectors are an essential component of computer
hardware that provides a means of communication between the hardware of a computer
and the user. These connectors are typically located at the front section of a computer
motherboard. The Figure 9.3 shows the schematic of front side case.
 Motherboard: A motherboard is the central printed circuit board (PCB) in many modern
computers and holds many of the crucial components of the system, while providing
connectors for other peripherals as shown in Figure 9.4. The motherboard is sometimes
alternatively known as the main board, system board, or, on Apple computers, the logic
board.
69
Experiment No. 09
Figure 9.3 Schematic of Front Side Case
Most computer motherboards produced today are designed for IBM-compatible computers,
which currently account for around 90% of global PC sales. A motherboard, like a backplane,
provides the electrical connections by which the other components of the system
communicate, but unlike a backplane, it also connects the central processing unit and hosts
other subsystems and devices. A typical desktop computer has its microprocessor, main
memory, and other essential components connected to the motherboard. Other components
such as external storage, controllers for video display and sound, and peripheral devices may
be attached to the motherboard as plug-in cards or via cables, although in modern computers
it is increasingly common to integrate some of these peripherals into the motherboard itself.
An important component of a motherboard is the supporting chipset of the microprocessor,
which provides the supporting interfaces between the CPU and the various buses and external
components. This chipset determines, to an extent, the features and capabilities of the
motherboard as shown in Figure 9.5.
70
Experiment No. 09
Figure 9.4 Schematic of Motherboard
Figure 9.5 Schematic of Motherboard

CPU: Central Processing Unit (CPU), or processor, is the heart of your computer no matter
what type (PC, Server, and Laptop) as shown in Figure 9.6. There are many brands for
processors such as Intel and Athlon all with different processors for your computer.
71
Experiment No. 09
Figure 9.6 Schematic of CPU

RAM: Random Access Memory (RAM) is the form of memory contained in most computers as
shown in Figure 9.7. When an application is running it stores its information in the RAM. When
you close the application, the information is deleted from the RAM.
Figure 9.7 Schematic of RAM

Hard-Disk Drive: A hard drive stores all your files and information in a permanent form unlike
storing it in RAM (which is temporary). The larger your hard disk (drive) the more information
and files you're able to store. The schematic of hard-disk drive iss shown in Figure 9.8.
Figure 9.8 Schematic of Hard-Disk Drive
72
Experiment No. 09

CD-ROM: The CD-ROM is reads CD's. CD-ROM completely stands for Compact Disk Read Only
Memory as shown in Figure 9.9. CD's have much more data than a floppy disk. Using CD-RW,
you can make your own CD's and use them more like a floppy disk.
Figure 9.9 Schematic of CD-ROM


DVD Rom: DVD-ROM is a digital optical disc storage format. DVDs offer higher storage
capacity than compact discs while having the same dimensions. Blank recordable DVD discs
(DVD-R and DVD+R) can be recorded once, Rewritable DVDs (DVD-RW, DVD+RW, and DVDRAM) can be recorded and erased multiple times.
Floppy Drive: A floppy drive reads the popular floppy disk as shown in Figure 9.10. Floppy disk
is easy to use, rewritable, compact, and great for storing information. The floppy drive is
simple and allows you to read, write to, and write over information stored on a floppy disk.
Figure 9.10 Schematic of Floppy Drive
3. Rear/Back Side Connecters: The back panel is the portion of the motherboard that lets you
connect external devices, such as your monitor, speakers, keyboard, and mouse. As seen in
the Figure 9.11 below, the back panel is on the edge of the motherboard. When installing the
motherboard, the back panel is on the back side of the case and is inserted into the cases I/O
plate.
73
Experiment No. 09
Figure 9.11 Schematic of Rear Side Case

SMPS: Switch Mode Power Supply uses electronics circuitry that converts the AC input
voltage to different values of regulated DC supply which are fed into various color-coded wires
fixed to connectors. The schematic of SMPS is shown in Figure 9.12.
Figure 9.12 Schematic of SMPS
74
Experiment No. 09

SMPS FAN: The fan is fixed inside the SMPS and is used to radiate the internal heat of the
SMPS to the outside. The schematic of SMPS Fan is shown in Figure 9.13.
Figure 9.13 Schematic of SMPS Fan


Power in Socket: This socket is used to input 220V AC to the PC from the main supply when
the computer switch on the front side is pressed.
PS-2 Port: You can see two different colored 6-pin round-shaped connectors as shown in
Figure 9.14. These connectors are used to connect input devices, keyboards, and mouse.
Color Coding defines the connector type. The purple connector is dedicated to connecting the
Keyboard and the Green color is used for Mouse.
Figure 9.14 Schematic of PS-2 Port

USB Port: The full form is Universal Serial Bus and is used to connect various input and output
devices like Mouse, Keyboard, Printers, Webcams, etc. USB 3.0 is the latest version which
offers a high data transfer speed as shown in Figure 9.15.
Figure 9.15 Schematic of USB Port
75
Experiment No. 09


DVI Port: Digital Video Interface is a high-speed serial link for connecting output Display
Devices.
HDMI Port: HDMI stands for a high-definition multimedia interface. This is the latest interface
that helps to get high-definition video and multi-channel sound. You can connect HDMIenabled blue ray devices, LEDs, etc. The schematic of DVI and HDMI port is shown in Figure
9.16.
Figure 9.16 Schematic of DVI and HDMI Port

15-pin Female VGA Port: This is used to connect display devices like Monitor / LCD / LED
Displays. The schematic of 15-pin female VGA port is shown in Figure 9.17.
Figure 9.17 Schematic of 15-pin Female VGA Port

LAN Port: The LAN or network port is used to connect to other devices and computers in a
network as shown in Figure 9.18.
Figure 9.18 Schematic of LAN Port
76
Experiment No. 09

Audio Ports: Generally, there is 3 number of audio ports on the back side of a PC. These parts
are either aligned vertically or in a horizontal position. The green color port is dedicated for
headphones or speakers, the blue colored port is marked as Line-in and Mic can be inserted
in a pink port as shown in Figure 9.19.
Figure 9.19 Schematic of Audio Port

Expansion Slots: These expansion slots are used to connect add-on cards to increase the
capabilities of the motherboard as shown in Figure 9.20.
Figure 9.20 Schematic of Expansion Slots
CONCLUSION:
Internal and external parts and components of a computer system have been studied.
Activity:
Look at the picture below, fill in the table below by referring it to the picture.
77
Experiment No. 09
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
Name
Explanation
78