Lkk01 Computer Hardware and Networking ppt

COMPUTER HARDWARE &
NETWORKING
By,
L. K. Kothwar
Lecturer – Electronics Engg
Government Polytechnic Ambad, Jalna, MH

COURSE OBJECTIVES
After completion of this course you will able to:
• Understand principle, construction, working of computer
peripherals
• Select cost effective, good quality reliable peripherals and
equipment
• Identify the problem as hardware or software related.
• Identify and repair the simple faults in computer systems.
• Plan, analyze, design, install, configure, test, implement and
maintain networking systems
Application :
• Selection of appropriate hardware based on application
• Repair and maintenance of PC’s
• Plan, analyze, design, install, configure, test, implement and
maintain networking systems 2

CONCEPT MAPPING
3
COMPUTER
(Hardware &
Networking)
Types
DIGITAL
•Micro
•Home
•PC
•Mainframe
•Super
•Mini
ANALOG HYBRID
Hardware
CPU
•ALU
•Motherb
oard
•Chipset
•Intel
945 G
•Register MEMORY
•DDR RAMs
•Cache
•Internal
•External
•L1,L2,L3
•CD/DVD
ROM
•BIOS
I/O
DEVICES
• Keyboard
• Mouse
• Monitor
POWER
SUPPLY
• SMPS
• UPS
• USB
Software
SYSTEM SOFT
• O/S
• Utility
Programs etc
APPLICATION
SOFT
• Web
• Mobile etc
Networking
CLASSIFI-
CATIONS
•LAN
•WAN
•MAN
•Peer to Peer
TOPOLOGY
CABLES
• Coaxial
• UTP
• STP
• Fiber
Optics
STANDARDS
• Ethernet
• Ring
• Token
• Wireless
DEVICES &
MODELS
• OSI
• Interlayer
Comm
• TCP/IP
Hubs
Switches
Routers
Bridge
Repeaters
Gateways
Firewalls
Diagnostic, Testing&
Maintenance
• Preventive
• Passive

Unit 1: MOTHERBOARD AND
PERIPHERALS

OBJECTIVES
After completion of this unit you will able to:
• Identify different components and their function on
motherboard
• Identify and compare storage devices
• Write specifications, select appropriate monitor and
compare LCD and CRT monitors
• Understand principle, construction and working of
peripherals
12/21/2018 Computer Hardware & Networking 5
Motherboard & Peripherals

CONTENTS
• Different types of PC configurations and their comparison, Chipset basic,
Architecture of Intel 945 G
• Overview and features of ISA, PCI-X, PCI-Xpress
• Overview features and types of DDR RAMs, Concept of cache memory : Internal
cache, External cache (L1, L2, L3 cache), OS Basics
• CD/DVD ROM drive : Construction, recording, comparison
• LCD monitor: functional block diagram of LCD monitor, working principle, Types-
Passive matrix and Active matrix. important characteristics - Resolution, Refresh
rate, Response time. Comparison of CRT display and LCD display
• Construction, working & Installation of Keyboard, mouse, Scanner and printer.
• Keyboard: Membrane and mechanical only.
• Mouse: Optical only, Scanner: Flatbed only, Printer: Dot matrix, Inkjet, and
Laser only

TYPES OF PC BASED ON CONFIGURATIONS
• Different types of PC Based on configurations
• Comparison
Computer
Digital
Micro
Home
PC
Mainframe
Super
MiniAnalog
Hybrid

• DIGITAL COMPUTER
• ANALOG COMPUTER
• HYBRID COMPUTER

• A Digital Computer works with digits to represent numerals, letters or
other special symbols.
• Digital Computers operate on inputs which are ON-OFF type and its
output is also in the form of ON-OFF signal.
• Normally, an ON is represented by a 1 and an OFF is represented by a
0.
• A digital computer can be used to process numeric as well as non-
numeric data.
• ANALOG COMPUTER
• HYBRID COMPUTER

• ANALOG COMPUTER
• Analog computers are used to process analog data. Analog data is of
continuous nature and which is not discrete or separate.
• Such type of data includes temperature, pressure, speedweight,
voltage, depth etc.
• These quantities are continuous and having an infinite variety of
values.
• HYBRID COMPUTER

• ANALOG COMPUTER
• HYBRID COMPUTER
• A hybrid is a combination of digital and analog computers.
• It combines the best features of both types of computers,i-e. It has the
speed of analog computer and the memory and accuracy ofdigital
computer.
• Hybrid computers are used mainly in specialized applications where
both kinds of data need to be processed. Therefore, they help the user,
to process both continuous and discrete data.

What makes a computer powerful?
• Speed
• A computer can do billions of actions per second.
• Reliability
• Failures are usually due to human error, one way or another.
• Storage
• A computer can keep huge amounts of data.
• Digital Computer Categories
• Mobile Computer
• Microcomputer
• Minicomputers
• Mainframes
• Supercomputer

COMPUTER OPERATIONS
• The computer is an electronic machine that performs the
following five basic operations:
• Input
• Process
• Store
• Control
• Output
Memory
Unit
Control
Unit
ALU
INPUT OUTPUT
Take Input Output Information
Control the workflow
Store Data
Process Data
CPU

HARDWARE vs SOFTWARE
• Hardware: It is any part of your computer that has a physical
structure, such as the computer monitor or keyboard.
• Software: It is any set of instructions that tells the hardware what
to do. It is what guides the hardware and tells it how to accomplish
each task.

BASIC COMPUTER COMPONENTS
DISPLAY UNIT
MAINBOARD
PRINTER
EXTERNAL HARD DRIVE
MOUSE
KEYBOARD
CPU
PLUG IN MEMORY MODULE
POWER
SUPPLY UNIT
SCANNER HARD DISK DRIVE
SPEAKER
PLUG IN CKT MODULE
CD/DVD ROM DRIVE

COMPUTER COMPONENTS
• System Unit
• The system unit is the core of a computer system.
• The most important of these components is the central processing unit
(CPU), or microprocessor, which acts as the "brain" of your computer.
• Another component is random access memory (RAM), which
temporarily stores information that the CPU uses while the computer is
on.
• Almost every other part of your computer connects to the system unit
using cables.

COMPUTER COMPONENTS
• Computer Case
• Where all of the components are stored.
• The computer case serves mainly as a way to physically mount and
contain all of the actual computer components.
• Cases typically come bundled with a power supply.
• Two types of casing:
• Tower
• Desktop
• Desktop and tower computers are two different styles of computer
case that use desk space in varying ways.
• Desktop computers are designed to lay flat on the desk, while towers
stand upright

COMPUTER COMPONENTS
• Power Supply
• Used to sends power to all of the other hardware so they can operate.
• Two types of power supply:
• –AT (Advanced Technology)
• –ATX (Advanced Technology Extended)
• Central Processing Unit (CPU)
• The CPU, or the Central Processing Unit, is the brain of the computer
and the single most important chip in the computer.
• The CPU performs the system's calculating and processing.

COMPUTER COMPONENTS
• Computer Memory
• Also known as Random Access Memory (RAM)
• Computer memory is used to store information in electronic devices.
• Motherboard
• The main circuit board of the computer.
• All key internal and external components of the computer plug into the
Motherboard.
• Components directly attached to the motherboard include:
• CPU, Chipset, Random-Access Memory(RAM), Read-Only Memory(ROM),
BIOS(Basic Input Output System), Buses, Ports

• Motherboard

COMPUTER COMPONENTS
• Hard disk
• It used to store computer data and
program.
• It can hold more data and are faster
than floppy disks
• Optical Disc Drive
• An optical storage technology that
stores and plays back data.
• Some drives can only read from discs,
but recent drives are commonly both
readers and recorders.

COMPUTER COMPONENTS
• Video card
• A board that plugs into a personal
computer to give it display capabilities.
• The display capabilities of a computer,
however, depend on both the logical
circuitry (provided in the video adapter)
and the display monitor.
• Sound card
• A circuit board that plugs into your
Motherboard that adds audio capability
to your computer, providing high quality
stereo output to the speakers.

COMPUTER COMPONENTS
• Modem
• Short for modulator-demodulator.
• A modem is a device or program that enables a computer to transmit data
over, for example, telephone or cable lines.
• Monitor
• The part of a computer that allows you to see what the computer is
processing.
• Other Components
•Input Devices
–Keyboard, mouse
•Output Devices
–Printer, speakers
•Operating System
–Windows, MacOS, Linux

• The CPU is the hardware device in a computer that executes all
of the instructions from the software
CENTRAL PROCESSING UNIT (CPU)
CPU ROM RAM I/O
BUS INTERFACE UNIT
ALU
Timing & Control
ADDRESS BUS
DATA BUS
CONTROL BUS
Fig: - A simple CPU design

• The bus interface unit takes the data to & from the CPU along
the Data bus to Read/Write memory & Input/output devices.
This is a two way bus. The bus interface unit also places the
required location addresses on to the Address Bus, so that the
input/output devices can be accessed. The ALU carries out all the
calculations & decisions. The Control bus gives indications of
whether the CPU is currently reading or writing to memory or to
I/O devices.

• ROM (Read Only Memory)
• Once data has been written onto a ROM chip, it cannot be removed
and can only be read. Unlike main memory (RAM), ROM retains its
contents even when the computer is turned off. ROM is referred to as
being nonvolatile, whereas RAM is volatile.
• RAM
• I/O
• ADDRESS BUS
• DATA BUS
• INTERNAL REGISTER

• ROM
• RAM (Random Access Memory)
• It is the internal memory of the CPU for storing data, program, and
program result. It is a read/write memory which stores data until the
machine is working. As soon as the machine is switched off, data is
erased.
• I/O
• ADDRESS BUS
• DATA BUS

• ROM
• RAM
• I/O
• ADDRESS BUS
• The address bus is the set of wires that carries the addressing
information used to describe the memory location to which the data is
being sent or from which the data is being retrieved.
• The size (or width) of the address bus indicates the maximum amount
of RAM a chip can address.
• DATA BUS

• ROM
• RAM
• I/O
• ADDRESS BUS
• DATA BUS
• The bundle of wires (or pins) used to send and receive data.
• The more signals that can be sent at the same time, the more data can be
transmitted in a specified interval and, therefore, the faster (and wider) the
bus.
• Modern processors data bus can transfer 64 bits of data at a time to and
from the motherboard chipset or system memory.

• ROM
• RAM
• I/O
• ADDRESS BUS
• DATA BUS
• The size of the internal registers indicates how much information the
processor can operate on at one time and how it moves data around
internally within the chip. This is sometimes also referred to as the
internal data bus.
• A register is a holding cell within the processor.

• Modes of operation of CPU : Processor modes refer to the various
ways that the processor creates an operating environment for itself.
Specifically, the processor mode controls how the processor sees and
manages the system memory and the tasks that use it.
• Real Mode
• IA-32 (Intel Architecture - 32)(Protected) Mode
• IA-32 Virtual Real Mode

• Process Technologies: Dual Independent Bus Architecture
• DIB uses two buses:
1. One from the processor to main memory, and The other from the processor to the
L2 cache.
2. The processor can access both buses simultaneously, which increases throughput.
• Hyper-Threading Technology:
1. HT Technology enables a single processor to execute 2 separate code streams
(called threads) concurrently.
2. HT technology allows 1 physical processor to appear as 2 “logical” processors to
software (O/S and applications).
• Each logical processor has its own architecture state with its own set of general-purpose and
control registers
• Some resources are shared (caches, exe units, buses, etc)

• Processor Sockets & Slots:
• A CPU socket or CPU slot is a mechanical component(s) that provides
mechanical and electrical connections between a microprocessor and a
printed circuit board (PCB).
• This allows the CPU to be replaced without soldering.
• A CPU socket is made of plastic, a lever or latch, and metal contacts for each
of the pins or lands on the CPU.
Fig: CPU Socket 775

• A chipset is a set of electronic components in an integrated
circuit that manages the data flow between the processor,
memory and peripherals. It is usually found in the motherboard
of a computer.
CHIPSET BASIC
SOUTH BRIDGE
PROCESSOR
NORTH BRIDGEAGP RAM
PCI
ISA
HDDI
SCSI
BIOS LAN

• Northbridge
1. Northbridge is also called Memory Controller Hub (MCH) in Intel Systems. It is one of the two chips in the core
logic chipset on the PC motherboard.
2. It handles communication between CPU, RAM, AGP or PCI Express and the Southbridge.
3. Some North-bridges also have the integrated Video controller called Graphics Memory Controller Hub (GMCH).
4. Since different processors and RAM require different signaling, a north-bridge will work with one or two types
of CPU and only one type of RAM It provides the number, Speed, type of CPU, Size, type of RAM that can be
used.
5. The north-bridge plays an important role in deciding how far a computer can be over- clocked.
6. It uses a heat sink and some kind of cooling (Fan).
• South bridge
1. The Southbridge, also known as the I/O Controller Hub (ICH)
2. It is a chip that implements the "slower" capabilities of the motherboard in north bridge/south bridge chipset
computer architecture.
3. It is not directly connected to the CPU. Rather, the north bridge ties the south bridge to the CPU.
4. A particular type of south bridge may work with different north bridge chipsets.
5. The interface between the north bridge and the south bridge is the PCI bus.
6. Bridge connection from Memory Controller Hub to slower devices like USB devices, PCI-X, IDE(SATA/PATA), Real
Time Clock, BIOS, onboard sound and more
CHIPSET BASIC

Architecture of Intel 945 G

• Latest chipset for PC
Latest chipset for PC

BUSES : ISA,PCI-X, PCI-Xpress
• ISA (industry Standard Architecture)
• ISA is the first open s/m bus architecture used for IBM-Type personal
computer.
• Both 8-bit and 16-bit version of ISA bus are available
1. 8-bit ISA bus:
2. 16-bit ISA bus
• Features

• PCI (Peripheral Component Interconnect):
• It is high performance Bus that is used to integrate chips, processor, memory subsystems and
expansion boards.
• Features of PCI bus:
1. Extremely High-speed data transfer: 32 bit wide data transfer @33 MHz gives a maximum
throughput of 132 mbps. Data transfer @66 MHz with 64 bit wide data is now being offered.
2. Plug & play facility: A PCI board inserted in any PCI slot is automatically detected & the
required i/o & memory resources are allotted by the system.
3. New Approach: It moves peripherals of the i/o bus & places them closer to the system
processor bus. Thereby providing faster data transfer between the processor & peripherals.
4. Processor Independent: The PCI local bus fulfills the need for the local bus standard that is not
directly dependent on the speed & structure of processor bus, and that is both reliable and
expandable.
5. Full multi master capability: This allows any PCI master to communicate directly with other PCI
master slave.
6. Parity on both data & address line: This allows implementation of robust systems (Robustness
is defined as "the ability of a system to resist change without adapting its initial stable
configuration") support for both 5 V & 3.3 V operated logic.
7. Forward & backward compatibility between 66MHz & 33MHz PCI

• PCI-X: PCI-X (Peripheral Component Interconnect Extended) is a
computer bus technology that increases the frequency of the data
bus from 66MHz to 133MHz.
• Features of PCI-X bus:
1. Up to 133MHz bus speed
2. 64 bit bandwidth
3. 1 Gbps throughput
4. More efficient bus operation for easier interface.
5. Split transaction allows & indicator device to make only one data request
& release the bus, instead of constantly needing to poll the bus for
response.
6. Byte count that enables indicators to specify in advanced, the specific
number of bytes requested, eliminating the inefficiency of involving a high
risk of loss pre fetches.
7. Backward compatibility.

• PCI-Express (Peripheral Component Interconnect Express (PCIe)):
• It is a scalable Input/output (I/O) serial bus technology that largely
replaced earlier PCI slots on motherboards.
• Features of PCI Express:
1. Point-to-Point connection: PCI Express is a point-to-point connection,
which means it does not share bandwidth but communicates directly with
devices via a switch that directs data flow.
2. Hot Swapping & Plugging: This allows for "hot swapping" or "hot
plugging," which means cards in PCIe slots can be changed without
shutting down the computer.
3. Less Power Consumption: It consumes less power than previous PCI
technology.
4. Scalable: One of the most promising features of PCI-Express is that it is
scalable, which means greater bandwidth can be achieved through adding
more "lanes."

MEMORIES
• Memory : It is workplace for the processor or temporary storage area
• RAM (Random Access Memory) is where data is stored that's being
accessed by the CPU.
• Types of RAM:
1. Static RAM:
• (Static RAM or SRAM) that holds data in a static form, that is, as long as the memory
has power.
• Unlike dynamic RAM, it does not need to be refreshed.
• Stores a bit of data on four transistors using two cross-coupled inverters.
• Faster and less volatile than dynamic RAM, but it requires more power and is more
expensive.
2. Dynamic RAM:
• stores each bit in a storage cell consisting of a capacitor and a transistor. Capacitors
tend to lose their charge rather quickly; thus, the need for recharging or refreshing.

MEMORIES
• Types of DRAM:
1. FPM (Fast Page Mode):
• Traditional RAM for PC.
• Mounted in single inline memory module (SIMM) of 2MB, 4MB, 8MB, 16MB, 32MB.
2. EDO (Extended Data Out): It is faster than FPM RAM. EDO have improvement in performance 2% to
5% compared with FPM.
3. ECC (Error Correcting Code): It is special error correcting RAM used in server.
4. SDRAM (Synchronous Dynamic RAM):
• It synchronizes data transfer between the CPU and memory.
• Allows the CPU to process data while another process is being queued.
• Features of SDRAM:
• All SDRAM chips for desktop PC have 168 pins
• Speed of SDRAM is 100 MHz & 133 MHz
• Available in sizes 32MB, 64MB, 128MB, 256MB, 512MB, & 1GB
• Operating Voltage 3.3 V
• Architecture used Synchronous
• Operating Max Temperature is 85oC
• It Pre-fetches 1 bit at a time

MEMORIES
• DDR (Double Data Rate SDRAM): also called DDR1 SDRAM.
• DDR SDRAM (double data rate SDRAM) is synchronous dynamic RAM
(SDRAM) that can theoretically improve memory clock speed to at least 200
MHz
• Features of DDR SDRAM:
• Chips have 184 pins.
• Comes in different speeds i.e.100Mhz, 133MHz, 166MHz, 200MHz
• DDR is twice as fast as SDRAM
• Operating Voltage 2.5 V
• Architecture used is Source Synchronous (it refers to the technique of having
the transmitting device send a clock signal along with the data signals.)
• Operating Max Temperature – 85oC
• It Pre-fetches 2 bit at a time

MEMORIES
• DDR2 (Double Data Rate 2 SDRAM):
Features of DDR2:
• The DDR2 RAM chip has 240 pins
• DDR2 operate at data rates of 400MHz,
533MHz, 667MHz, & above
• Higher Bandwidth
• Lower power 1.8V
• Architecture used source synchronous
• It pre-fetches 4 bits at a time
• Operating Max Temperature – 95oC
• DDR3 (Double Data Rate 3 RAM):
Features of DDR3:
• Introduction to asynchronous RESET pin.
• Support system level same delay
compensation. On DIMM (dual in-line
memory module) mirror friendly DRAM pin
out.
• Introduction of CWL (CAS Write Latency) per
Speed bin.
• On-die I/O calibration engine.
• READ & WRITE calibration.
• It works on very low power i.e.1.5V
• DDR3 operate at data rates of 800MHz,
1066MHz, 1333MHZ, 1600MHz, & above.
• It pre-fetches 8 bits at a time.

CACHE MEMORY
•“The cache is a very high speed and very expensive
piece of memory, which is used to speed up the
memory retrieval process.”
• Recently used instructions and data are kept in a very fast memory so
that the CPU does not have to access the main memory every time it
requires access to data.
• Cache memory is random access memory (RAM) that a computer
microprocessor can access more quickly than it can access regular RAM.

CACHE MEMORY
• As the microprocessor processes data, it looks first in the cache memory
and if it finds the data there (from a previous reading of data), it does not
have to do the more time-consuming reading of data from larger
memory.
• Cache is a smaller, faster, memory which stores copies of data from most
frequently used main memory location.
• Cache memory is a high speed memory buffer that processor need allows
processor to retrieve data faster than it will come from main memory.
• The advantage of cache memory is that CPU does not have to use the
motherboard bus for data transfer.

CACHE MEMORY
•Types of Cache Memory:
• L1 (Level 1 or Internal or Primary) Cache
• L2 (Level 2 or External or Secondary) Cache
• L3 Cache

CACHE MEMORY
• L1 (Level 1 or Internal or Primary) Cache:
• Called primary cache, is a static memory integrated with processor core
that is used to store information recently accessed by a processor.
• The purpose is to improve data access speed in cases when the CPU
accesses the same data multiple times.
• The L1 cache typically ranges in size from 8KB to 64KB and uses the high-
speed SRAM (static RAM) instead of the slower and cheaper DRAM
(dynamic RAM) used for main memory.
• L2 (Level 2 or External or Secondary) Cache:
• L3 Cache:

CACHE MEMORY
• L2 (Level 2 or External or Secondary) Cache:
• Called secondary cache, is a memory that is used to store recently accessed
information.
• The goal of having the level 2 cache is to reduce data access time in cases when
the same data was already accessed before. This also reduces data access time.
• Please note that the level 2 caches is secondary to the CPU - it is not as fast as the
level 1 cache, although it is usually much larger.
• All data that is requested from level 2 cache is copied to level 1 cache. Requested
data stays in the secondary cache if it's an inclusive cache, and is removed from
secondary cache if it's an exclusive cache.
• L2 caches come between L1 and RAM (processor-L1-L2-RAM) and are bigger than
the primary cache (typically 64KB to 4MB).
• L3 Cache:

CACHE MEMORY
• L2 (Level 2 or External or Secondary) Cache
• L3 Cache:
• L3 caches are found on the motherboard rather than the processor. It is
kept between RAM and L2 cache.
• Cache Hit: A request to read from memory which can satisfy from the
cache without using the main memory.
• Cache Miss: A request to read from memory which cannot be satisfied
from the cache, for which the main memory has to be consulted.
• The percentage time cache hit is called as Cache Hit Ratio

BIOS BASICS
•Definition: Basic Input/output System, the BIOS, ROM BIOS, or
System BIOS is a chip located on all motherboards that contain
instructions and setup for how your system should boot and how it
operates.
• The main function of BIOS in a computer is to offer a small library
of basic input/output functions that are used to run and manage
computer peripherals.

BIOS BASICS
• Main functions that the BIOS perform include:
• A power-on self-test (POST) for all of the different hardware components in the
system to make sure everything is working properly
• Activating other BIOS chips on different cards installed in the computer - For
example, SCSI and graphics cards often have their own BIOS chips.
• Providing a set of low-level routines that the operating system uses to interface
to different hardware devices. Managing a collection of settings for the hard
disks, clock, etc.
• The BIOS is special software that interfaces the major hardware components of
your computer with the operating system. It is usually stored on a Flash
memory chip on the motherboard, but sometimes the chip is another type of
ROM.

BIOS BASICS
• CMOS
• The CMOS setup utility is used to setup the hardware configuration of
your computer's motherboard. It's the same function as the BIOS utility.
It has things like disk boot order, RAM settings, and system clock settings
(so your computer knows what time it is).
• “There are some differences between a warm and cold booting. A warm
boot is what happens when a computer is running and it is restarted. A
cold boot is when the computer is already off and the power is turned
on.”
• To boot (also "to boot up") a computer is to load an operating system into
the computer's main memory or random access memory (RAM).
• A bootstrap is the process of starting up a computer. It also refers to the
program that initializes the operating system (OS) during start-up.

Motherboard Selection Criteria
•Knowing What to Look For:
• It helps to think like an engineer when you make your selection. Consider every
aspect and detail of the motherboards in question. For instance, you should consider
present usage as well as any future uses and upgrades. Technical support at a
professional (as opposed to a user) level is extremely important. The following list
includes some of the most important criteria to consider when selecting a
motherboard:
8. Basic Input Output System (BIOS)
9. Form Factor
10.Built-in Interfaces
11.On-board IDE interfaces
12.Power Management
13.Documentation
14.Technical Support
1. Motherboard Chipset
2. Processor
3. Processor Sockets
4. Motherboard Speed
5. Cache Memory
6. SIMM/DIMM/RIMM memory
7. Bus Type

CD/DVD ROM Drive
• Optical Storage:
• Optical technology standard can be divided into three types:
• CD (Compact Disc)
• CD-ROM, is an optical read only storage medium based on the original CD-DA
(Digital Audio) format first developed for the audio CDs
• CD-R (Recordable), CD-RW (Rewritable)
• CD-ROM standard is an 80-minute disc with a data capacity of 700MB
• DVD (Digital Versatile Disc)
• BD (Blue-ray Disc)

CD/DVD ROM Drive
• CD (Compact Disc) ROM Drive
• Construction :
• Made up of polycarbonate wafer, 120mm in diameter and 1.2mm thick with
a 15mm hole in the center
• The Steps in manufacturing CDs

CD/DVD ROM Drive
CD (Compact Disc) ROM Drive
• Working

CD/DVD ROM Drive
• CD (Compact Disc) ROM Drive
• Working

CD/DVD ROM Drive
• DVD (Digital Versatile Disc) ROM Drive
• Construction :
• Click here..
• DVD-5 : 4.7GB, DVD-9 : 8.5GB, DVD-10 : 9.4GB, DVD-18:17.1GB
• Comparison

LCD MONITOR
Functional Block Diagram
:

LCD MONITOR
• Working principle :
• The main principle behind liquid crystal molecules is that when an
electric current is applied to them, they tend to untwist.
• Liquid Crystal Display technology works by blocking light.
• LCD is made up of two pieces of polarized glass (also called substrate)
that contain a liquid crystal material between them.
• A backlight creates light that passes through the first substrate.
• This causes a change in the light angle passing through them. At the
same time, electrical currents cause the liquid crystal molecules to
align allow varying levels of light to pass through to the second
substrate & create the color images.

LCD MONITOR
• Types :
• Passive Matrix
• Active Matrix

LCD MONITOR
• Characteristics :
1. Dot Pitch: Distance between two adjacent pixel centers.
2. Resolution: It is number of horizontal & vertical pixels.
3. Refresh rate: The refresh rate is the number of times in a second that
display hardware draws the data.
4. Response time: The minimum time necessary change in pixel color or
brightness.
5. Viewable size: CRT monitor gives viewable size in diagonal measures
from 15 inch to 42 inch.
6. Color Support: Number of types of color is supported.

OTHER I/O DEVICES
• KEYBOARD (Membrane & Mechanical Only)
• A keyboard is a typewriter-style device, which uses an arrangement of
buttons or keys, to act as electronic switches.
• Different types of key Switches in Keyboard:
1. Capacitive Key Switch
2. Membrane Key Switch
3. Rubber Dome Key Switch
4. Hall Effect Key Switch
5. Opto-Electronic Key Switch
6. Mechanical Key Switch

OTHER I/O DEVICES
• MEMBRANE KEYBOARD SWITCH

OTHER I/O DEVICES
• MEMBRANE KEYBOARD SWITCH
• It is a multi-layer plastic or rubber assembly.
• It is used as keyboard in video game machines, calculators, medical
instruments, cash registers etc.
• Two rubber or plastic sheets are used as row conductor sheet &
column conductor sheet.
• Rows & columns line are made on the plastic or rubber sheet using
silver or some other conductor ink.

OTHER I/O DEVICES
• MECHANICAL KEYBOARD SWITCH

OTHER I/O DEVICES
• MECHANICAL KEYBOARD SWITCH
• Two metal pieces or contacts are kept in open position & moved into
closed position when switch is pressed.
• When the switch is in normal position the contact is open, when the
switch is pushed the contact closes, & the closure is sensed by the
keyboard interface.
• After some use contacts become oxidized or dirty & make the switch
useless.
• Gold plating on these contacts is done to improve the life span of the
switch.
• Normal life span of high quality switches is about 1 million keystrokes.

OTHER I/O DEVICES
• MOUSE (Optical Only)
• A computer mouse is an input device that is most often used with a
personal computer.
• Moving a mouse along a flat surface can move the on-screen cursor to
different items on
• the screen. Items can be moved or selected by pressing the mouse
buttons.

OTHER I/O DEVICES

OTHER I/O DEVICES
• Working:
• In this type of mouse, a light source & photo detector is used with a special
mouse pad.
• When the optical mouse is moved on this special pad, light from the light
source gets reflected from the pad & special photo detector inside the
mouse detects the horizontal & vertical movements.
• Two photo detectors are there, among that one of the photo detectors is
used to detect vertical movement of the cursor on the screen & the other is
used to detect the horizontal movement of the cursor on the screen.
• The movement of the cursor on the screen depends on the number of the
signals that is passed to the PC through the wire connected with the mouse.
• The PC, in turn, passes them to the mouse driver software which then
converts the distance, & speed required for the movement of the screen
cursor.

OTHER I/O DEVICES
• SCANNER (Flatbed Only)

OTHER I/O DEVICES
• PRINTER (Dot Matrix, Inkjet & Laser Only)
• Printers are Output devices used to prepare permanent Output devices
on paper. Printers can be divided into two main categories:
• Impact Printers: In this hammers or pins strike against a
ribbon and paper to print the text. This mechanism is known
as electro-mechanical mechanism.
• Non-Impact Printers: There printers use non-Impact
technology such as ink-jet or laser technology. There printers
provide better quality of O/P at higher speed.

OTHER I/O DEVICES
• PRINTER - Dot Matrix

OTHER I/O DEVICES
• PRINTER - Inkjet

OTHER I/O DEVICES
• PRINTER - Laser

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