Lesson Plan
Course Title: Computer Maintenance
Session Title: Safety/Electrostatic Discharge (ESD)
Lesson Duration: Approximately 120 Minutes
Performance Objective:
Upon completion of this assignment, students will be able to recognize the effects of
electrostatic discharge (ESD) while working around computer components. The student will be
able to discuss and demonstrate ways to minimize or eliminate the damaging impact of ESD on
sensitive electrical and computer equipment.
Specific Objectives:
 Describe what (ESD) is and why it is important to a computer technician.
 Describe the damage that can be caused by ESD to electrical and computer components.
 Describe ways of preventing or eliminating ESD.
 Describe and/or demonstrate effective ESD Workstation Components.
Preparation
TEKS Correlations: 130.273(C) (1) (G)
… identify and implement proper safety procedures.
Instructor/Trainer
References:
1. JES and Co., A+ Certification: Introduction to Computer Hardware, Lesson 3: Preventing
ESD.
Instructional Aids:
 PowerPoint presentation: Safety/Electrostatic Discharge (ESD)
 PowerPoint presentation: Safety/Electrostatic Discharge (ESD) – Handouts
 ESD Workstation/Environment – Lab 1
 ESD Workstation/Environment – Lab 2
 ESD Workstation/Environment – Lab 3
 Safety/Electrostatic Discharge (ESD) Exam
 Safety/Electrostatic Discharge (ESD) Exam Key
Materials Needed:
 Standard computer technician tool kit with wrist-strap [for each pair of students]
 Copies of Lab Sheets for ESD Workstation [for each student]
 ESD floor and table mats [for each team working on lab]
 Anti-static bags [electrically conductive and electrically dissipative versions]
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
1
Equipment Needed:
 Projection system to display the PowerPoint presentation [PC/Monitor, PC/Projector, etc.]
 One PC for each two students, for labs.
 A multimeter for each two students, for labs.
Learner
Students should read the appropriate curriculum material for electrostatic discharge (ESD)
[depending on the text/curriculum being used for this course]. This lesson can be taught with
only the PowerPoint presentation, and the equipment outlined above.
Introduction
MI
Introduction (LSI Quadrant I):
Electrostatic discharge can easily damage electrical components with a single touch.
An electrostatic discharge occurs when two objects having different potential
energies approach each other. Even a slight ESD can cause computer components
to fail.
The human body can only feel an electrostatic discharge of around 3,000 volts or
more; does anyone know how many volts can damage or destroy the delicate
circuitry found in computers?
[Less than 100 volts can damage or destroy the delicate circuitry found in
computers.]
Outline
MI
Outline (LSI Quadrant II):
Instructor Notes:
I. Introduce students to Electrostatic Discharge
(ESD):
A. What Electrostatic Discharge (ESD) is
B. Why ESD is important to a computer
technician
C. Ways of preventing ESD damage
D. The components of an ESD Workstation:
1. ESD wristband or ankle strap
2. ESD floor or table mat
3. ESD garments
4. ESD gloves or finger covering
5. Increased humidity
6. Anti-static bags
II. Demonstrate an ESD Workstation.
III. Students complete lab demonstrations, including
A. Lab 1: Assemble an ESD Workstation
B. Lab 2: Mount a PC onto the ESD
Workstation
C. Lab 3: Test the ESD Workstation
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
2
Application
MI
Guided Practice (LSI Quadrant III):
1. The teacher shows and demonstrates each lab principle.
2. The teacher maintains direct supervision in the lab, providing guidance when
warranted.
MI
Independent Practice (LSI Quadrant III):
1. Students work in pairs on lab assignments, demonstrating their skills with
identifying and discussing the various lab requirements and results.
Summary
MI
Review (LSI Quadrants I and IV):
1. Ask the students summary questions:
a. Why worry about ESD? [A small amount of ESD can damage sensitive
electronic and computer components.]
b. What is the most essential component of an ESD Workstation? [The ESD
wristband]
c. What is better for controlling ESD: increased humidity or decreased humidity
and why? [Increased humidity allows electrons to be able to discharge
safely into the air instead of another object]
Revisit the steps the students went through to create an ESD Workstation.
Evaluation
MI
Informal Assessment (LSI Quadrant III):
1. The teacher will monitor student progress during independent practice and
provide independent re-teach/redirection as needed.
MI
Formal Assessment (LSI Quadrant III, IV):
1. Administer the ESD Exam.
Extension
MI
Extension/Enrichment (LSI Quadrant IV):
Students that have mastered the lab assignments can peer-tutor students [one-onone] that are having difficulty with understanding the concept of an ESD workstation.
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
3
Icon
MI
Verbal/
Linguistic
Logical/
Mathematical
Visual/Spatial
Musical/
Rhythmic
Bodily/
Kinesthetic
Intrapersonal
Interpersonal
Naturalist
Existentialist
Teaching Strategies
Personal Development
Strategies
Lecture, discussion, journal
writing, cooperative learning,
word origins
Reading, highlighting, outlining,
teaching others, reciting information
Problem-solving, number
games, critical thinking,
classifying and organizing,
Socratic questioning
Mind-mapping, reflective
time, graphic organizers,
color-coding systems,
drawings, designs, video,
DVD, charts, maps
Use music, compose songs
or raps, use musical
language or metaphors
Organizing material logically, explaining
things sequentially, finding patterns,
developing systems, outlining, charting,
graphing, analyzing information
Developing graphic organizers, mindmapping, charting, graphing, organizing
with color, mental imagery (drawing in
the mind’s eye)
Use manipulatives, hand
signals, pantomime, real life
situations, puzzles and board
games, activities, roleplaying, action problems
Reflective teaching,
interviews, reflective listening,
KWL charts
Cooperative learning, roleplaying, group brainstorming,
cross-cultural interactions
Natural objects as
manipulatives and as a
background for learning
Socratic questions, real life
situations, global
problems/questions
Creating rhythms out of words, creating
rhythms with instruments, playing an
instrument, putting words to existing
songs
Moving while learning, pacing while
reciting, acting out scripts of material,
designing games, moving fingers under
words while reading
Reflecting on personal meaning of
information, studying in quiet settings,
imagining experiments, visualizing
information, journaling
Studying in a group, discussing
information, using flash cards with
others, teaching others
Connecting with nature, forming study
groups with like-minded people
Considering the personal relationship to
the larger context
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
4
Computer Maintenance – Electrostatic Discharge Lab
Lab 1: Assemble an ESD Workstation
Student Name: _____________________________ Date: __________
Objective
Focus on your ability to gather and identify components that make up an ESD Workstation.
Equipment
The following components are required for this exercise:
• ESD wrist strap and cable
• ESD mat
• Ground cord
Scenario
You have just been hired by a local computer store as a repair technician. The store has not had a repair
facility before. You are left to your expertise and experience to establish an area to diagnose and
troubleshoot PCs.
Procedures
With the exception of monitors, all computer equipment should be examined and repaired on an ESD
Workstation.
1st Step
Gather and identify the following components:
• ESD wrist strap and cable: one end of the cable attaches to the wrist strap, the other plugs into the
ESD mat. You may have to unplug the alligator clip on the far end of the ESD wrist strap to plug it
into the ESD mat.
• ESD mat: this rubberized mat has plugs or cables to connect the mat to an ESD wrist strap, the
computer case, and ground.
• Ground cord: one end plugs into the ESD mat and the other end contains a one-prong electrical
plug instead of three-prong plug. The single-prong plugs into the rounded slot of a three-prong wall
socket.
2nd Step
Lay the ESD mat on the table with the snap connector facing up. Attach the ground cable to the snap
connector on the mat.
3rd Step
Leave the ground cord unplugged.
4th Step
Attach the ESD wrist strap to its cable and plug the other end into the ESD mat.
Summary: You have just identified and assembled the components necessary for an ESD workstation.
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
5
Computer Maintenance – Electrostatic Discharge Lab
Lab 2: Mount a PC onto the ESD Workstation
Student Name: _____________________________ Date: __________
Objective
Focus on your ability to attach a computer to an ESD Workstation.
Equipment
The following components are required for this exercise:
• The ESD Workstation established in LAB 1
Scenario
You have just been hired by a local computer store as a repair technician. The store has not had a repair
facility before. You are left to your expertise and experience to establish an area to diagnose and
troubleshoot PCs. You are now ready to begin working on your first computer.
Procedures
The purpose of this exercise is to learn how to properly attach a computer to an ESD Workstation.
1st Step
Ensure that the computer is turned off.
2nd Step
Move the computer to the ESD mat.
3rd Step
Without opening the computer case, unscrew one of the four screws attaching the power supply to the
frame.
4th Step
Screw the ground cable into the frame using the power supply screw.
5th Step
Wrap the ESD wrist strap around your right wrist.
6th Step
Leave the computer on the ESD Workstation for use during the next exercise.
Summary: You have mounted a computer on an ESD Workstation.
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
6
Computer Maintenance – Electrostatic Discharge Lab
Lab 3: Test the ESD Workstation
Student Name: _____________________________ Date: __________
Objective
Focus on your ability to test an ESD Workstation using a multimeter
Equipment
The following components are required for this exercise:
• The ESD Workstation established in Lab 1
• The PC mounted to the ESD Workstation in Lab 2
• Multimeter
Scenario
You have just been hired by a local computer store as a repair technician. The store has not had a repair
facility before. You are left to your expertise and experience to establish an area to diagnose and
troubleshoot PCs. You are now ready to begin working on your first computer. You need to test the ESD
workstation prior to beginning work on the PC.
Procedures
The purpose of this exercise is to insure that an ESD Workstation is setup properly, test the workstation
using a multimeter.
1st Step
If necessary, attach the probes to your multimeter.
Set your multimeter to Ohms.
• A multimeter set to Ohms measures resistance. If there is an unobstructed electrical path between
two objects, the objects have connectivity, and the resistance is zero. If there is no electrical path,
the objects have no connectivity, and the resistance is infinite.
2nd Step
Test the multimeter’s Ohm setting by touching one probe against the other.
• When probes are touching, the resistance should be zero. When the two probes are pulled apart,
the resistance should read infinity.
• Multimeters with an LED display often represent infinity by displaying the number 1 on the far left
of the screen.
• If the multimeter is not working properly check the following:
• Check that the probes are seated correctly and plugged into the proper position.
• Ensure that the multimeter is set to Ohms. This setting is characterized by a horseshoeshaped symbol.
• Test the batteries. Multimeter batteries are often drained by forgetting to set them to the OFF
position before storage.
• The multimeter may need to be adjusted.
3rd Step
Unplug the ESD workstation from the wall. Test the connectivity between the computer frame and the
ground connector on the wall plug. What is the reading?
_______________________________________________________________________
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
7
4th Step
Test the connectivity between the frame and the wrist strap at the point it touches the wrist.
• What is the resistance? (You may have to adjust the scale on the multimeter to the highest setting)
________________________________________________________________
________________________________________________________________
________________________________________________________________
•
Why isn’t the resistance zero?
________________________________________________________________
________________________________________________________________
________________________________________________________________
•
Why should the ESD wrist strap be attached to the right wrist?
________________________________________________________________
________________________________________________________________
________________________________________________________________
Summary: You used a multimeter to test connectivity. You used the multimeter to check whether an ESD
Workstation was properly assembled.
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
8
Computer Maintenance – Electrostatic Discharge
Exam
DIRECTIONS: Circle the letter that corresponds to the best answer for each of the
questions below.
Question 1: The human body can feel an electrostatic discharge of how much voltage?
A. < 100 volts
B. 100 – 300 volts
C. 1000 volts
D. 3000 volts or more
Question 2: To ensure you don’t cause electrostatic damage to systems you are
servicing, you should establish which one of the following?
A. A PC Workstation
B. An ESD Workstation
C. An anti-static Workstation
D. A low humidity work environment
Question 3: Which of the following is true concerning ESD and humidity?
A. ESD buildup is greatly increased in a humid environment
B. As the presence of moisture in the air is decreased, electrons are better able
to discharge safely into the air instead of another object
C. Using a humidifier to increase the air moisture in your work area can greatly
reduce ESD buildup.
D. Too much humidity cannot damage sensitive electronic components
Question 4: Which kind of anti-static bag can be used over long periods of time without
losing effectiveness?
A. Electrically conductive bags
B. Electrically dissipative bags
C. Electrically manipulative bags
D. No anti-static bag can be used for long periods of time effectively
Question 5: What color is an electrically dissipative bag usually?
A. Black, coated with a metallic or carbon layer
B. Grey, coated with a metallic weave
C. Pink, coated with a substance that slows the transference of ESD
D. Pink, coated with a carbon layer or a metallic weave
Question 6: Which kind of anti-static bag will degrade over time?
A. Electrically conductive bags
B. Electrically dissipative bags
C. Electrically manipulative bags
D. All anti-static bags can be used for long periods of time effectively
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
9
Question 7: ESD gloves or finger covering that are good for anti-ESD work can be
made from which of the following?
A. Silk
B. Rayon
C. Nylon
D. Vinyl
Question 8: Which of the following is NOT a component of an ESD Workstation?
A. ESD wristband
B. ESD floor or table mats
C. Anti-static bags
D. Nylon carpeting
Question 9: Which of the following statements is true concerning damage caused by
ESD?
A. Damage is always immediately apparent
B. Errors caused by ESD are always duplicable
C. Partial damage can result in intermittent errors in the computer
D. Discharge of high levels of electricity into wires and components not designed
to accept such levels will not always result in damage
Question 10: Electrical resistance is measured in which of the following?
A. Amps
B. Ohms
C. Volts
D. Watts
Question 11: You should ground yourself with an ESD wrist strap when working on all
of the following except
A. Memory board
B. Motherboard
C. Drive cables
D. Hard drive
Question 12: When servicing a PC, where do you attach the ground cord to prevent
ESD?
A. Connect one end at the ESD mat and the other end in the ground slot of a
three-prong wall socket.
B. Connect one end at the ESD wrist strap and the other end in the ground slot of
a three-prong wall socket.
C. Connect one end at the metal table and the other end at the ESD wrist strap
D. A ground cord is not necessary when wearing an ESD wrist strap
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
10
Question 13: What device is used to measure resistance?
A. A multimeter
B. A resistance meter
C. A volt meter
D. Resistance cannot be measured
Question 14: Decreasing humidity in a work area will do which of the following?
A. Reduce ESD buildup
B. Increase ESD buildup
C. Electrons are better able to discharge safely into the air
D. Cause condensation that can damage sensitive components
Question 15: Which of the following is true concerning ESD garments?
A. Worn over your clothing and provides a ground wire to attach to an ESD mat
B. Worn under your clothing and provides a ground wire to attach to an ESD mat
C. Worn under your clothing and provides a ground wire to attach to a wall plug
D. Worn over your clothing and provides a ground wire to attach to a wall plug
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
11
Computer Maintenance – Electrostatic Discharge Exam
(Key)
DIRECTIONS: Circle the letter that corresponds to the best answer for each of the questions
below.
Question 1: The human body can feel an electrostatic discharge of how much voltage?
A. < 100 volts
B. 100 – 300 volts
C. 1000 volts
D. 3000 volts or more
Question 2: To ensure you don’t cause electrostatic damage to systems you are
servicing, you should establish which one of the following?
A. A PC Workstation
B. An ESD Workstation
C. An anti-static Workstation
D. A low humidity work environment
Question 3: Which of the following is true concerning ESD and humidity?
A. ESD buildup is greatly increased in a humid environment
B. As the presence of moisture in the air is decreased, electrons are better able
to discharge safely into the air instead of another object
C. Using a humidifier to increase the air moisture in your work area can
greatly reduce ESD buildup.
D. Too much humidity cannot damage sensitive electronic components
Question 4: Which kind of anti-static bag can be used over long periods of time without
losing effectiveness?
A. Electrically conductive bags
B. Electrically dissipative bags
C. Electrically manipulative bags
D. No anti-static bag can be used for long periods of time effectively
Question 5: What color is an electrically dissipative bag usually?
A. Black, coated with a metallic or carbon layer
B. Grey, coated with a metallic weave
C. Pink, coated with a substance that slows the transference of ESD
D. Pink, coated with a carbon layer or a metallic weave
Question 6: Which kind of anti-static bag will degrade over time?
A. Electrically conductive bags
B. Electrically dissipative bags
C. Electrically manipulative bags
D. All anti-static bags can be used for long periods of time effectively
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
12
Question 7: ESD gloves or finger covering that are good for anti-ESD work can be
made from which of the following?
A. Silk
B. Rayon
C. Nylon
D. Vinyl
Question 8: Which of the following is NOT a component of an ESD Workstation?
A. ESD wristband
B. ESD floor or table mats
C. Anti-static bags
D. Nylon carpeting
Question 9: Which of the following statements is true concerning damage caused by
ESD?
A. Damage is always immediately apparent
B. Errors caused by ESD are always duplicable
C. Partial damage can result in intermittent errors in the computer
D. Discharge of high levels of electricity into wires and components not designed
to accept such levels will not always result in damage
Question 10: Electrical resistance is measured in which of the following?
A. Amps
B. Ohms
C. Volts
D. Watts
Question 11: You should ground yourself with an ESD wrist strap when working on all
of the following except
A. Memory board
B. Motherboard
C. Drive cables
D. Hard drive
Question 12: When servicing a PC, where do you attach the ground cord to prevent
ESD?
A. Connect one end at the ESD mat and the other end in the ground slot of
a three-prong wall socket.
B. Connect one end at the ESD wrist strap and the other end in the ground slot of
a three-prong wall socket.
C. Connect one end at the metal table and the other end at the ESD wrist strap
D. A ground cord is not necessary when wearing an ESD wrist strap
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
13
Question 13: What device is used to measure resistance?
A. A multimeter
B. A resistance meter
C. A volt meter
D. Resistance cannot be measured
Question 14: Decreasing humidity in a work area will do which of the following?
A. Reduce ESD buildup
B. Increase ESD buildup
C. Electrons are better able to discharge safely into the air
D. Cause condensation that can damage sensitive components
Question 15: Which of the following is true concerning ESD garments?
A. Worn over your clothing and provides a ground wire to attach to an ESD
mat
B. Worn under your clothing and provides a ground wire to attach to an ESD mat
C. Worn under your clothing and provides a ground wire to attach to a wall plug
D. Worn over your clothing and provides a ground wire to attach to a wall plug
IT: Computer Maintenance: Safety/ Electrostatic Discharge Plan
Copyright © Texas Education Agency, 2011. All rights reserved.
14