Computer Hardware
Objectives
• Input Devices and Their Uses
• Output Devices and Their Uses
• Processing Device and Their Uses
• Communication Devices
• Compare Storage Devices
Computer Hardware
• The physical components of a computer are
called hardware.
• Peripheral devices complete the input, output,
and storage tasks.
• Hardware—physical components
• Processing—computer’s responsibility
• Input, output, storage—handled by peripheral
devices
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Processing Hardware• The processing function is done by the Central
Processing Unit which is located in the System Unit.
• The computer’s brain is the central processing unit
(CPU). Located inside the system unit on the
motherboard.
• It consists of two parts: the arithmetic logic unit and
the control unit.
– The arithmetic logic unit (ALU) performs arithmetic and logic
calculations.
– The control unit coordinates the movement of data through
the CPU. These two parts of the CPU enable it to execute the
program instructions.
Central Processing Unit
Control
unit
Arithmetic
logic unit
Central
processing
unit
Instruction Cycle
• The instruction cycle, or machine cycle, processes each
instruction in the CPU. During the fetch operation, the
instruction is retrieved from the random access memory
of the computer’s motherboard.
• The decode step translates the instruction into a form that
can be understood by the CPU.
• In the execute step, the ALU processes the arithmetic
operations and logic decisions, producing either a
number or a value of true or false.
• The store operation moves the results back to an internal
register or memory location for future use or storage.
Central Processing Unit
• Excessive heat builds as multiple processors
work, and the heat generated by the CPU
could eventually harm it.
• A heat sink and cooling fan are an
important part of the system for dissipating
the heat that builds up.
• Case fans in the system unit help to keep
the entire system cool. Be sure that you do
not block the air vents of a computer.
Parts of a System Unit
Parts of the Motherboard
The main circuit board of the computer is the motherboard. The CPU sits on
top of the motherboard.
Expansion cards
Expansion cards fit into expansion slots on the motherboard to connect additional
peripheral devices to the computer. Video cards, network cards, sound cards, and TV
tuners are common expansion cards
Expansion cards
• Data buses are wires on the motherboard that carry the
data between the components of the computer.
• The speed of the data bus is an important factor in the
performance of the computer.
Parts of a System Unit
• BIOS
–Read-only
memory
–Nonvolatile
• CMOS
–Volatile memory
• Memory
–RAM
– Cache
CMOS (complementary metal oxide semiconductor)
Input Devices
An input device enables you to input data into the
computer system for processing.
• Keyboard
• Pointing devices
• Mouse
• Optical mouse—LED
• Touchpad
• Touchscreen
– Stylus
– Resistive screen
– Capacitive screen
– Interactive whiteboard
Input Devices
Digital cameras
– LCD—liquid crystal display
– CSCs—compact system cameras
– DSLRs—digital single lens reflex cameras
– Webcams
– Digital video cameras
Input Devices
Scanners
– Optical scanner
– QR code—Quick Response code
– RFID—radio frequency identification
• RFID scanner
• RFID tag
– Magnetic strip reader
– Biometric scanners
– NFC—near field communication
Input Devices
• Microphones
• Game controllers and joysticks
• Adaptive input devices
• Voice-recognition software
• Wearable tech
Output Devices
Monitors
– Pixels
– Resolution
– Plasma screen monitors
– OLED—organic light-emitting diode
Monitor
• The most common devices for displaying output are
monitors and printers. Most flat panel monitors use
LCD (liquid crystal display) technology, which
creates the image you see on the screen by
manipulating light within a layer of liquid crystal.
• Flat-panel monitors labeled as LED (light emitting
diode) monitors use LEDs to provide the backlight.
LED backlighting is more energy efficient than
ordinary backlighting. One problem with LCD is that
when you view the monitor from an angle, it can be
hard to see the images on it. LED backlighting helps
solve this problem.
• Factors that influence the quality of a monitor’s
output are screen size, resolution, and dot pitch.
• Screen size is the diagonal measurement in inches
from one corner of the screen to the other.
• Resolution is the number of pixels the monitor can
display.
– Standard resolutions range from 640 × 480 to 1600 ×
1200.
• Dot pitch (dp) measures the distance between
pixels, so a smaller dot pitch means a sharper image.
A .28 or .26 dp is typical for today’s monitors.
Monitor
Output Devices
• An output devices helps to produce a result of a
processing or manipulation.
• Projectors
– DLP—digital light-processing projector
– LCD projector
• Speakers
• Headphones
• Headset = headphones + microphone
Printer
• A printer produces a paper copy of the text or
graphics processed by the computer.
• The most popular printers for business use are laser
printers. They use the same technology as a
photocopier; a temporary laser image is
transferred onto paper with a powdery substance
called toner.
• The speed of laser printers is measured in pages per
minute (ppm).Color laser printers use several toner
cartridges to apply color to the page.
• A less expensive alternative to the laser printer is an
inkjet printer.
Output Devices
Adaptive Output Devices:
– Magnified screens
– Speech synthesis screen reading software
– Audio alerts
– Closed captions
– Visual notifications
– Braille embosser: Is a special type of printer that prints
in Braille so that text can be read by touch.
Storage Devices
• A storage device records and retrieves data from a
storage medium
– Data gets copied from a storage device into RAM, where it waits
to be processed
– Processed data is held temporarily in RAM before it is copied to
a storage medium
• Optical discs
– Forms:
– Read-only (ROM)
– Recordable (+R/-R)
– Rewritable (+RW/-RW)
– CD—compact disc
– DVD—digital video disc, digital versatile disc
– Blu-ray disc
Storage Devices
• Solid-state storage - is non-mechanical with the
data stored on nonvolatile flash memory
• Flash memory
• Flash drives—connect via USB port
• Memory cards—use card reader
– SD, CF, MS, xD
Storage Devices
Hard drives
–Internal drives
–External drives
• USB port
Hardware Security
• Anti-theft Devices
• Surge Protection and Battery Backup
• Basic Maintenance
Surge Protection and Battery Backup
• A power surge is a sudden increase in electrical energy,
affecting the current that flows to electrical outlets.
• A surge strip is a device that contains electrical outlets
protected by circuitry that blocks surges.
• A UPS is a device that not only provides surge
protection, but also furnishes your computer with battery
backup power during a power outage.
Surge Protection
and Battery Backup
Basic Maintenance
• Computer component failures can be caused by
manufacturing defects and other circumstances beyond
your control
• Keep the keyboard clean
• Clean your computer screen on a regular basis
• Keep the area clean around your computer
• Make sure fans are free of dust
Basic Maintenance
Troubleshooting and Repair
• There are several telltale signs that your computer is in
trouble
– Failure to power up
– Loud beep
– Blank screens and/or error messages
– Blue screen of death
• Troubleshooting and diagnostic tools
• Safe Mode
Troubleshooting and Repair
Summary
• In this lecture, we explored the hardware of a computer
system beginning with the central processing unit, or
CPU, which is the brain of the computer.
• The motherboard is the circuit board over which data
travels. It also enables devices, such as disk drives,
keyboards, mice, and printers, to be connected to the
computer.
• Devices attached to the computer can be divided into
their functional areas of input, processing, output, and
storage.
• With input devices you provide data to the computer.
Output devices produce the information that comes
from processing.
• Storage devices enable you to save the data even after
turning off the computer or exiting a program.