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TRANSCRIPT
Chapte
r
1 Introduction to
a Typical PC
Chapter
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Objectives
• Give examples of how computers are used.
• Contrast analog and digital electronics.
• Give examples of computer data.
• Interpret binary and hexadecimal numbers 0
through 15.
• Compare bit, byte, and word.
• Contrast serial and parallel data transfer.
• Interpret the common prefixes associated with
the computer’s size and speed.
• Identify external computer connections.
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Objectives (Continued)
• Identify the major components of a typical PC.
• Explain how the major computer components
interact with each other.
• Contrast electrostatic discharge,
electromagnetic interference, and radio
frequency interference.
• Identify common PC service tools.
• Recall common safety practices related to
computer repair.
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Key Terms
• A+ Certification
• American Standard Code for Information Interchange (ASCII)
• analog electronics
• anti-static wrist strap
• battery
• binary number system
• Bit
• byte
• central processing unit (CPU)
• CompTIA
• computer
• cooling fan
• data
• device bay
• digital electronics
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Key Terms (Continued)
• driver
• electromagnetic interference (EMI)
• electrostatic discharge (ESD)
• expansion card • expansion card slot
• external SATA
• firmware
• hard drive
• hexadecimal number system
• hot swap
• integrated circuit (IC)
• motherboard
• parallel transfer
• peripheral
• power eSATA (eSATAp)
• power supply
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Key Terms (Continued)
• radio frequency interference (RFI)
• random access memory (RAM)
• serial transfer
• word
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Introduction to a Typical PC
• A+ Certification awarded after successful
completion of the CompTIA A+ exams
– A+ Certification recognized throughout the industry
– A+ Certification covers basic PC repair and support
skills
– CompTIA is a not-for-profit, vendor-neutral
organization that certifies the competency level of
technicians
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The Role of Computers
• Computers are part of every aspect of our lives.
• The make up of a computer can seem
intimidating, but the mechanics are simple.
• This textbook teaches skills to be successful in
computer technology.
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Digital Electronics
• All electronic components fall into one of two
categories: digital electronics and analog
electronics.
– Digital electronics is an electronic system
represented by a simple switch, which is either on
or off.
– Analog electronics is an electronic system that
uses and produces varying voltage levels.
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Digital Electronics (Continued)
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Digital System
Analog System
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Describe the difference between a digital and
an analog electronic device.
Digital devices accept discrete levels of input
and produce discrete levels of output. Analog
devices accept continuous ranges of input to
produce continuous ranges of input to produce
continuous ranges of output.
Review
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What Is a Computer?
• A computer is an assembly of electronic modules
that interact with computer programs known as
software to create, modify, transmit, store, and
display data.
– Computers have rapidly evolved from simple
electronic devices to highly sophisticated pieces of
technology.
– Computers appear to be intelligent but really only
process and store data.
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What Is a Computer? (Continued)
• Data is information that is stored and processed
by computers.
– Data inside the computer is represented
electronically as high and low voltages, which
create a digital signal.
– Data in a computer system is represented as ones
and zeroes, a pattern known as the binary system.
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Computer Data Codes
• Data can be numbers, text, pictures, or sound.
• Data can be expressed in different forms.
– Voltage levels
– Numeric systems
• Binary
• Hexadecimal
– Symbolic codes, such as ASCII
• Data should be expressed in the way that is
easiest to grasp for the given material.
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Computer Data Codes (Continued)
• The binary number system consists of entirely
ones and zeroes.
– Digital devices have two states (off and on), which
are reflected in two numbers (0 and 1).
– One and zeros of this system are used to represent
high and low voltage signals.
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Computer Data Codes (Continued)
Binary Number System
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Computer Data Codes (Continued)
• The hexadecimal number system is a computer
code system that uses 16 characters.
– The system uses a combination of numerals 0
through 9 and the letters A through F.
– It best matches the hardware systems of
computers.
– The system can be used in combination with the
binary system.
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Computer Data Codes (Continued)
Hexadecimal Number System
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Computer Data Codes (Continued)
• American Standard Code for Information
Interchange (ASCII) is a symbolic code in which
data can be expressed.
– It was the first attempt to standardize computer
character codes among the varieties of hardware
and software.
– It had limitations, such as not allowing for
variations in fonts, a common requirement of word-
processing software.
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Bits, Bytes, and Words
• Bit, byte, and word are basic computer units of
data based on the binary number system.
– Bit, short for binary digit, is a single binary unit of
one or zero.
– A byte is equal to eight bits.
– A word is the total amount of bytes a computer can
process at one time.
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Bits, Bytes, and Words (Continued)
Unit Definition Example
Bit 0 or 1 1
Byte eight bits 01011110
Word 1 to 8 bytes 10010010 11110000 00110011
10101010
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Serial and Parallel Data Transfer
• Data is transferred in one of two modes in a
computer system: series or parallel.
• Ports in a computer are classified as serial or
parallel.
– In a serial transfer, data is sent through a port one
bit at a time in successive order.
– In parallel transfer, more than one bit is sent side
by side, eight bits at a time.
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Serial and Parallel Data Transfer (Continued)
Serial and Parallel Data Transfer
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Computer Numerical Values
• Metric prefixes are used to express the speed and
size of computer systems and hardware.
• Prefixes are used in combination with the word bit
(b) or byte (B).
– Speed is usually expressed in bits.
– Storage is usually expressed as bytes.
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Computer Numerical Values (Continued)
Metric Prefix Chart
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Computer Numerical Values (Continued)
Comparison between Base 2 and Base 10 Number Systems
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The binary system consists of the decimal
numbers ____ and ____.
0,1
There are eight ____ in one____.
bits, byte
Describe the difference between serial data
transfer and parallel data transfer.
In a serial transfer, data is sent through a port
one bit at a time in successive order; in parallel
transfer, more than one bit is sent side by side.
Review
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Take a Tour Outside the Computer Case
• A minimal workstation consists of a computer and
input and output devices.
– The computer is a case that houses the
motherboard, CPU, memory, and hard drive.
– Typical input devices include the keyboard and
mouse.
– Typical output devices are the monitor, printer, and
speakers.
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Take a Tour Outside the Computer Case (Continued)
• Peripherals are optional pieces of equipment used
to display data or to input data.
– Monitor displays data as words or pictures.
– Printer displays data in printed form.
– Speakers convert data into sound.
– Keyboard is used to enter data.
– Mouse is used to interact with coordinates on the
display.
– Touch screen can be both input and output.
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Take a Tour Outside the Computer Case (Continued)
• There are many different case styles used to
contain and protect the electronic part of a
computer.
• Most common case styles
– Desktop
– Tower
– Mini tower
– Micro tower
– Laptop
– Notebook
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Take a Tour Outside the Computer Case (Continued)
• Exterior of the computer allows access to the
electronic parts inside.
• Data can be entered through the hard drive,
optical drive, keyboard, mouse, or one of the ports
in the back.
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Take a Tour Outside the Computer Case (Continued)
• Mini-DIN is an exterior connection used for the
mouse and the keyboard that may not be
interchangeable.
• FireWire is an exterior connection also known as
the IEEE-1394 connector.
– Made to allow hot swaps, meaning a device
can be plugged in or unplugged while the PC is
running
– Made for very high-speed data transfers
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Take a Tour Outside the Computer Case (Continued)
• Universal Serial Bus (USB) is a multipurpose
exterior connection that allows many different
devices to connect to a PC.
– Connects up to 127 devices in a daisy-chain
fashion
– Eliminates the need to open the PC case to
connect some peripherals
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Take a Tour Outside the Computer Case (Continued)
• A device bay is a drive bay designed to
accommodate the easy hot swap of devices such
as hard drives, tape drives, and optical drives.
– Prewired for either USB or FireWire
– Eliminates the problem of running long cords
across work surfaces
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Take a Tour Outside the Computer Case (Continued)
• There are two types of RJ connectors commonly
used: RJ-11 and RJ-45.
– RJ-11 for telephone connections
– RJ-45 for network connections
• DB connector looks similar in shape to the letter
D.
– Options include a 9-, 15-, or 25-pin
– Current computers have no DB connections,
replaced by USB
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Take a Tour Outside the Computer Case (Continued)
• VGA, DVI, and HDMI are used as monitor
connections.
– VGA is used for analog connections.
– DVI and HDMI are used for digital connections.
• External SATA devices require two connections.
– External SATA port provides a data connection to
an external SATA device.
– Power eSATA port, also called the eSATAp,
provides data connection and electrical power.
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Take a Tour Outside the Computer Case (Continued)
Typical Exterior Connections
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Take a Tour Inside the Computer Case
• The inside of a PC has several standard components.
– Central processing unit (CPU)
– Power supply
– Hard drive
– Motherboard
– RAM
– Firmware
– Battery
– Expansion cards
– Expansion card slots
– Cooling fan
– Cables
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Take a Tour Inside the Computer Case (Continued)
• The central processing unit (CPU) is the brain
of the computer.
– Intel® Core® i7, Intel® Pentium® , Intel® Celeron®,
AMD FV 8-Core, and AMD Phenom™ are various
models of CPUs.
– All other components depend on the CPU.
– CPU controls the data in the computer.
– The CPU translates commands into actions.
– CPU carries out the program codes written in the
software program.
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Take a Tour Inside the Computer Case (Continued)
AMD Athlon™ 64 FX-70 series processor. Courtesy of Advanced Micro
Devices, Inc.
One CPU Model
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Take a Tour Inside the Computer Case (Continued)
• The power supply converts the 120-volt ac
power from the wall outlet to dc voltage levels
used by the various computer components.
• The hard drive is where computer programs and
data are stored.
– The hard drive is also called the internal hard drive
or hard disk drive.
– Programs and data are stored as magnetic
patterns on the hard drive.
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Take a Tour Inside the Computer Case (Continued)
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Hard Drive Power Supply
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Take a Tour Inside the Computer Case (Continued)
• The motherboard is usually a rectangular piece
of circuit board covered with many conductors
that provide electrical energy paths to the
computer components and expansion slots.
– The motherboard provides a way to distribute the
digital signals.
– The motherboard is an electrical system of
pathways referred to as the computer bus.
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Take a Tour Inside the Computer Case (Continued)
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Motherboard
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Take a Tour Inside the Computer Case (Continued)
• Random access memory (RAM) is where
computer programs are loaded to and from the
hard drive.
– RAM is classified as volatile memory, meaning that
data is lost when the power is turned off.
– The amount of RAM required to run applications
will vary.
– RAM is where data is temporarily stored.
– RAM is emptied when a computer is turned off.
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Take a Tour Inside the Computer Case (Continued)
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Three Difference Types of RAM Modules
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Take a Tour Inside the Computer Case (Continued)
• Firmware is hardware-specific software required
to boot the computer and support communication
between the operating system and hardware
devices.
– Interprets commands of higher-level software
programs, such as operating systems.
– Translates the commands into actions hardware
devices, such as the hard drive, can understand.
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Take a Tour Inside the Computer Case (Continued)
• Firmware and drivers work hand in hand.
– A driver is a small software program written
specifically for a hardware device.
– Drivers allow operating system to properly
communicate with a device.
– Without the driver, the device will not function
properly.
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Take a Tour Inside the Computer Case (Continued)
• CMOS, and BIOS are distinctly different from
firmware.
– CMOS is where the Setup utility stores information
about the computer’s hardware, date, and time.
– BIOS is a type of firmware written in machine
language.
• Machine language uses hexadecimal codes to write
a program.
• Because there is no single BIOS standard, BIOS
systems are diverse.
• BIOS soon will be replaced by UEFI.
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Take a Tour Inside the Computer Case (Continued)
• The battery supplies voltage to the CMOS, which
contains the firmware setup data.
– Without the battery, the computer would lose the
date, time, and all important information about the
hardware components when the power switch is
turn off.
– The battery allows information to be saved while
the PC is powered down.
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Take a Tour Inside the Computer Case (Continued)
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Computer Battery
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Take a Tour Inside the Computer Case (Continued)
• An expansion card is a board that can be easily
installed in a computer to enhance or expand its
capabilities.
– An expansion card is also called an interface card
or host adapter.
– This component is used for such devices as TV
tuners, video cards, sound cards, and modems.
– Many devices designed to be added to expansion
cards have been redesigned as exterior devices
that connect typically through a USB port.
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Take a Tour Inside the Computer Case (Continued)
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Expansion Card
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Take a Tour Inside the Computer Case (Continued)
• An expansion card slot is a receptacle for an
expansion card, which allows the card to connect
to the motherboard’s circuitry.
• The cooling fan supplies a constant stream of air
across the computer components.
• Cables, such as the SATA and the PATA, connect
the motherboard to devices such as the hard drive
and optical drive.
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Take a Tour Inside the Computer Case (Continued)
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SATA and PATA Cables
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Expansion Card Slots
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How the Major Parts Work Together
1. Power switch is turned on and electrical power
goes from the wall outlet into the computer
system.
2. Firmware system is activated and performs a
power-on self-test (POST), checking the RAM,
ROM, hard drive, and keyboard.
3. Operating system takes control of the system.
4. CPU waits for activity to be generated by the
mouse, keyboard, modem, or other input device.
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How the Major Parts Work Together (Continued)
5. Mouse pointer is moved to an icon and the mouse is clicked to activate a program, such as a word-processing program.
6. Some typing is done, and the save command is issued by clicking the save icon. The operating system takes over to interpret the command.
7. The firmware translates the instructions from the operating system to the storage media, activating the hard drive motor and actuator arm.
8. Control is returned to the program, so long as an error had not occurred.
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Integrated Circuits
• The term chip is often used in the computer
industry and is the final product of the
manufacturing of an integrated circuit.
• An integrated circuit (IC) is a collection of
transistors, resistors, and other electronic
components reduced to an unbelievable small
size.
• Over six million transistors manufactured as an
integrated circuit can fit into an area the size of a
dime.
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Integrated Circuits (Continued)
• Manufacturing an integrated circuit takes many
hundreds of steps.
– The circuit is drawn on a very large scale and
drawings are photographed.
– The negative of the photograph is used as a
template.
– An ingot of pure silicon is made and sliced into thin
wafers to serve as the base.
– A series of layers are produced over the silicon
wafer using a process called photolithography.
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Integrated Circuits (Continued)
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Manufacture of Integrated Circuits
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Integrated Circuits (Continued)
• A coating of a chemical called photoresist is laid
over the entire surface of the wafer, which will
react when exposed to UV light.
• Ultraviolet light is shone through the negative,
causing the photoresist to leave a pattern of soft
and hard surfaces in the exact pattern of the
designed circuit.
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Integrated Circuits (Continued)
• The soft photoresist is washed away, leaving an
etched pattern of valleys and ridges on the
surface of the wafer.
• The valleys are filled in with conductive material,
called doping or implantation.
• The process is repeated multiple times until 20 or
more layers are developed over the entire wafer.
• Single wafer is cut into several individual circuits.
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Integrated Circuits (Continued)
• Electrostatic discharge (ESD) is best defined in
the world of computer maintenance as the
transfer of static electrical energy from one object
to another.
– An ESD will damage the circuits of a microchip.
– Technicians wear an anti-static wrist strap, which
connects the technician to ground and bleeds off
any electrostatic charge.
– Electronic parts and devices are shipped inside
anti-static bags to prevent ESD.
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Integrated Circuits (Continued)
Anti-Static Kit
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Integrated Circuits (Continued)
• Electromagnetic Interference (EMI) is
interference or damage to components caused by
magnets and magnetic fields.
– Any device that operates on magnetic principles
should not come in contact or close proximity to a
magnetic field.
– Most common source of a magnetic field is
magnetic tools.
– Some computer chips can be damaged by strong
magnetic force, but most are designed with
magnetic shielding.
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Integrated Circuits (Continued)
• Radio frequency interference (RFI) is
interference produced by electronic devices that
use radio waves.
– Wireless network devices can fail or operate
erratically because of radio frequencies broadcast
by other devices.
– Common devices that generate RFI are cell
phones, cordless phones, wireless network
components, and microwave ovens.
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What components are found in a typical computer
workstation?
Some common PC components are CPU, cooling
fan, motherboard, RAM power supply, hard drive,
expansion cards, and cables.
What is the purpose of the battery mounted on the
motherboard?
The battery supplies voltage to the CMOS chip that
contains the firmware setup data.
Describe the difference between ESD, EMI, and RFI.
ESD is a static charge of electricity; EMI is
interference or damage to components caused by
magnets and magnetic fields; and RFI is interference
produced by electronic devices that use radio waves.
Review
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Tool Kit
• Computer repair requires a minimum number of
tools and can vary.
– A variety of screwdrivers are needed, a chip
puller, anti-static wrist strap, multimeter, extra
screws, and an extraction device are helpful.
– Canned compressed air may be necessary.
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Tool Kit (Continued)
• A software tool kit is important as well.
– Software will be used to troubleshoot,
diagnose, and repair PCs.
– Many software tools can be found as
shareware, which is software that is freely
distributed, usually via the Internet.
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Safety
• Safety is the responsibility of everyone.
• Precautions should be taken to ensure physical
safety.
– Cables, such as power cords or network cables,
should be properly secured to avoid causing a
tripping hazard.
• Tape the cable to the floor
• Use a cable floor runner
– Avoid touching electronic components while the
computer is energized.
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Safety (Continued)
• Other steps should be taken to ensure physical
safety of computer technicians and users.
– Loose clothing and inappropriate footwear should
not be worn in the computer repair environment.
– When the weight of an object exceeds 50 pounds,
two or more people should lift it or special
equipment designed for lifting and hauling heavy
objects should be used.
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Safety (Continued)
• Electrical hazards in a computer lab should be
understood.
– Do not attempt to open, inspect, or repair any electronic
device that you have not been trained on by your
instructor or if you have nor received your instructor’s
permission.
– Disconnect electrical power before opening any
computer case.
– Remove jewelry before working inside a computer
case.
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Safety (Continued)
• The possibility of fire is always a threat in a
computer laboratory.
• The acronym PASS is used to remember the
proper procedure for using a fire extinguisher
P = Pull the pin.
A = Aim at the base of the fire.
S = Squeeze the handles together slowly to discharge the fire extinguisher.
S = Sweep the nozzle from side to side moving carefully toward the fire while keeping the discharge aimed at the base of the fire.
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Safety (Continued)
Five Classes of Fire Extinguishers
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Safety (Continued)
• Computer technicians come into contact with hazardous materials and thus, need to practice chemical safety.
– A Material Safety Data Sheet (MSDS) is required by federal law for hazardous materials.
– An MSDS includes proper handling, storage, and disposal of the material, and health effects or harmful effects from breathing and contact with skin or eyes.
– The Environmental Protection Agency (EPA) provides information about how to properly dispose of and recycle electronic equipment.
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What does the fire protection acronym PASS
represent?
Pull the pin. Aim at the base of the fire.
Squeeze the handles. Sweep the nozzle side to
side at the base of the fire.
What government organization is responsible
for safety education and enforcement in the
work area?
The Occupational Safety and Health
Administration (OSHA) is responsible for safety
education and enforcement in the work area.
Review