Module 8—Electricity and Power Supplies

Lab Check off Sheet and Report

 

Certification Tests and Objectives Covered in Labs

A+ Operating System

A+ Hardware

Network+

Windows 2000 Professional 70-210

Windows 2003 Server 70-290

CISCO 640-801

 

1.0 OS Fundamentals

X

1.0 Installation, Configuration, and Upgrading

 

1.0 Media and Topologies

 

Installation

 

Managing and Maintaining Physical and Logical Devices

 

Planning and Designing

 

2.0 Installation, Configuration and Upgrading

X

2.0 Diagnosing and Troubleshooting

 

2.0 Protocols and Standards

 

Implementing and Conducting Administration of Resources

 

Managing Users, Computers, and Groups

 

Implementation and Operations

 

3.0 Diagnosing and Troubleshooting

X

3.0 Preventative Maintenance

 

3.0 Network Implementation

 

Implementing, Managing, and Troubleshooting Hardware Devices and Drivers

 

Managing and Maintaining Accesses to Resources

 

Troubleshooting

 

4.0 Networks

 

4.0 Motherboards, Processors, and Memory

 

4.0 Network Support

 

Monitoring and Optimizing System Performance and Reliability

 

Managing and Maintaining a Server Environment

 

Technology

 

 

 

5.0 Printers

 

 

 

Configuring and Troubleshooting the Desktop Environment

 

Managing and Implementing Disaster Recovery

 

 

 

 

 

6.0 Basic Networking

 

 

 

Implementing, Managing, and Troubleshooting Network Protocols and Services

 

 

 

 

 

 

 

 

 

 

 

Implementing, Monitoring, and  Troubleshooting Security

 

 

 

 

 

Check off each of the labs as you complete them below. Turn this in with your lab reports.

 

Requirement

Completed

Filled Out Lab Sheet

Not Attempted (0 on labs for unit)

Lab 8-1 Basics of Electricity

 

 

 

Lab 8-2 Basic Electrical Circuits

 

 

 

Lab 8-3 Measuring Ohms

 

 

 

Lab 8-4 Power Troubleshooting

 

 

 

Lab 8-5 Power Protection

 

 

 

Lab 8-6 How a Power Supply Works

 

 

 

Lab 8-7 Testing a Power Supply

 

 

 

Lab 8-8 Price and Power Comparisons

 

 

 

Lab 8-9 Power Supply Facts

 

 

 

Lab 8-10 Total Wattage in Your Computer

 

 

 

 

Lab 8-1 Basics of Electricity

 

Go to the following webpage and go through the interactive electricity lab for an overview of the basics of electricity.

 

http://ippex.pppl.gov/interactive/electricity/

 

  • Before beginning, get a balloon from me.

 

As you do the lab, answer the questions below.

 

1.       What is an atom?

 

2.       What is the normal “charge” of an atom?

 

3.       Define electricity.

 

Before doing the balloon thing, get AWAY from the computers. Static electricity can kill the computer. When you rub a balloon on your head you literally create tens of thousands of volts! This voltage has no current and is literally waiting to be conducted to another source. Touching a good conductor, such as metal, moves the voltage from your body through to the grounded object you just touched. Scuff your shoes on the carpet and that’s 10,000+ volts being built up. The more painful the shock, the higher the voltage!

 

That’s why some physicists call static electricity high voltage electricity!

4.       Why will a balloon rubbed against your hair or a wool sweater stick to a wall?

 

5.       Charge up your balloon and try to stick it to your neighbor’s balloon. Does it stick? Why or why not?

 

6.       Since rubbing your hair against the balloon, or your feet on the carpet, creates a positive charge, why is it important to ground yourself before working on a computer?

 

7.       What happens during a storm that causes lightning?

 

8.       Describe how electricity flows through a wire.

 

9.       Define resistance

 

10.   A copper wire would have what kind of resistance?

 

11.   Why are plastic and glass good insulators?

 

12.   How do you get an atom or group of atoms to create electricity?

 

13.   Define volts

 

14.   What is the purpose of a switch in an electrical circuit?

 

15.   How can you measure the current passing through a wire?

 

16.   What is this measurement called?

 

17.   As resistance gets ________ amps get higher.

 

18.   As voltage gets higher, amps get ________.

 

19.   In magnetism, opposite poles _____ and similar poles ______.

 

20.   Describe a magnetic field.

 

21.   What is a simple way to make a magnet?

 

22.   Circling a magnet around a wire will produce what?

 

Extrapolate from what you learned.

23.   Why is it important to keep small magnets away from computers?

 

24.   How come static electricity can fry a computer component?

 

25.   Why are there different wattage ratings for different power supplies?

 

 

 

Lab 8-2 Basic Electrical Circuits

 

Requirement

Check

Created circuit

 

Added switch

 

Drawing of circuit

 

Measured voltage

 

Measured amps

 

Answered questions

 

Cleaned up station

 

 

 

Objective

The objective of this lab exercise is to demonstrate and define basic concepts and terminology related to the study and use of electricity. After completing this lab exercise, you will be able to:

7  _ Create a simple switched circuit.

7  _ Describe the relationship between voltage, amperage, ohms, and wattage.

7  _ Use a multimeter to measure voltage and amperage.

 

Materials Required

7  _ One 9-volt battery (AA is an acceptable substitute)

7  _ One multimeter (capable of measuring amps)

7  _ One incandescent light bulb rated at 12 volts

7  _ One switch

7  _ Three pieces of standard-grade electrical wire

7  _ Electrical tape to attach wires to the battery, if necessary

 

Lab Setup & Safety Tips

7  Each group will require a clean desktop area for building their switched circuit.

7  The instructor must demonstrate for each student group how to configure the multimeter to measure volts and amps.

 

ACTIVITY

Creating a circuit

  1. Attach one piece of wire to each lead on the light bulb.
  2. Attach one of the wires to the battery’s lead.
  3. Attach the second wire to the other battery lead.
  4. Observe the results. What happened?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  1. In the space provided below, draw a diagram demonstrating the flow of electricity in the circuit you have created. Be sure to note the direction of the current’s flow.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Adding a switch

1. Disconnect the wire from the negative side of the battery.

2. Attach the wire to an available lead on the switch.

3. Attach the third wire to the other switch lead and then attach it to the battery.

4. Observe how the switch manages the circuit. What happens?

 

 

 

 

 

 

Measuring voltage

1. Configure your multimeter to measure the voltage of your circuit.

2. Attach the +/- leads from your multimeter to the respective +/- sides of the light bulb.

3. Be sure that the switch is turned to the ON position.

4. Record the voltage of your circuit:

 

 

 

 

Measuring amps

1. Configure your multimeter to measure the amps of your circuit.

2. Disconnect the wire that is not currently attached to the switch.

3. Attach the respective +/- side of the multimeter to the battery lead that is not attached to any wires.

4. Attach the respective +/- side of the multimeter to the light bulb that is not attached to any wires.

5. Turn the switch to the ON position.

6. Record the amps found in your circuit:

 

 

 

 

Review Questions

 

Circle True or False.

1. Resistance is measured in ohms. True / False

2. A switch can act as a break in a circuit. True / False

3. AC is the acronym for ampere. True / False

4. A multimeter can measure only voltage. True / False

5. In a circuit, amps and volts are always the same amount when measured. True / False

6. Describe the difference in multimeter placement for measuring volts and amps.

 

 

Lab Notes

7  What does AC mean?—Alternating current (AC) is current that cycles back and forth rather than traveling in only one direction. Normally between 110 and 125 AC volts are supplied from a standard wall outlet.

7  What are amps?—Amps are units of measurement for electrical current. One volt across a resistance of one ohm will produce a flow of one amp.

7  What are volts?—A volt is a measure of electrical pressure differential. A computer power supply usually provides four separate voltages: +12 V, -12 V, +5 V, and -5 V.

7  What is wattage?—Wattage is a measure of the total amount of power that is needed to operate an electrical device.

7  What are ohms?— An ohm is the standard unit of measurement for electrical resistance. Resistors are rated in ohms.

 

Lab 8-3 Measuring OHMs

 

Lab Checkoff

Requirement

Completed

Measure and record the resistance of a number of cables

 

Demonstrate the proper use of a multimeter for measuring ohms

 

 

 

Objective

The objective of this lab exercise is for you to identify the resistance of a variety of different conductors:

  • Describe how to use a multimeter to measure resistance.
  • Identify the levels of conductivity of a variety of cables

 

Materials Required

7  Multimeter

7  Cat 5 copper cable

7  Wire

7  Section of speaker cable

7  Other cables

 

Lab Setup & Safety Tips

7  Remember that when measuring ohms you must have the power turned off, so if you’re going to measure a power supply, for example, turn off and disconnect the power.

 

ACTIVITY

Setting up the multimeter

  1. Go to the website (link on our module page) that tells you how to set up the multimeter to measure ohms.
  2. Touch the leads together to make sure you’re getting a 0 ohm reading.

 

 

Measuring different wires

  1. Get a variety of wires from me and from places around the room. Some examples might be
    1. Dead power supply
    2. IDE cable
    3. USB cable
    4. Speaker cable
    5. CAT 5 cable
  2. Following the directions in the website, measure the different types of cables and record the characteristics and ohms below.
  3. Measure the four required cables and find three others in the room.
  4. If you can’t get a reading, make a note of that and explain WHY you can’t get a reading with our multimeters.
  5. Answer the questions below.

 

Wire/Cable

Type of conductor (copper, aluminum, etc.)

Measurement

Notes

Cat5 Cable

 (be sure to measure wire for wire…if you touch one end to the blue/white, be sure you’re testing blue/white on the other end)

 

 

 

Speaker wire

 

 

 

Red wire from box

 

 

 

Yellow wire from box

 

 

 

Other______________

 

 

 

Other______________

 

 

 

Other______________

 

 

 

 

 

 

Review Questions

  1. Describe ohms.

 

 

  1. Describe how to measure ohms using a multimeter.

 

 

 

 

 

 

  1. Which wire had the highest resistance?

 

 

  1. What kind of metal was it made of?

 

  1. Which wire had the lowest resistance?

 

 

  1. What kind of metal was it made of?

 

  1. Using the information gathered in the table above, if you were creating a cable for high speed transmission, what kind of wire/metal would you want to use?

 

 

  1. Why?

 

 

Lab 8-4 Power Troubleshooting

 

Pair up with another student and find a computer.

 

Student One: Come to me and get a Student 1 sheet. Follow the directions on the sheet and complete the lab.

 

Student Two: After student one has done his/her thing, come and get a sheet for student 2 from me and complete the lab.

 

Fill out the lab report.

 

Lab 8-5 Power Supply Protection

 

Lab Checkoff

 

Requirement

Completed

Install surge protector

 

Installed UPS

 

Recorded results of loss of power

 

Answered questions

 

Cleaned up area

 

 

 

Objective

The objective of this lab exercise is for you to install and configure a surge protector and an uninterruptible power supply (UPS) device. After completing this lab exercise, you will be able to:

7  Describe the functionality of a surge protector.

7  Properly install and configure a surge protector.

7  Describe the functionality of a UPS device.

7  Properly install and configure a UPS device.

7  Properly install and configure a power conditioner.

 

Materials Required

7  One computer

7  One surge protector

7  One UPS device of any type

7  One power conditioner

 

Lab Setup & Safety Tips

7  Always unplug the power cord and properly ground yourself before touching any component inside a computer.

 

ACTIVITY

Installing a surge protector

  1. Power off your lab workstation.
  2. Power off your monitor and any other peripheral devices.
  3. Plug the provided surge protector into the wall outlet.
  4. Plug each of your peripheral devices into the surge protector (this includes the system unit and monitor).
  5. Power on the surge protector.
  6. Power on your lab workstation.
  7. Power on your monitor and other peripheral devices (this includes the system unit and monitor).
  8. Verify that your PC is functioning properly.

 

 

Installing a UPS device

  1. Power off your system unit.
  2. Power off any additional peripherals that you want to be protected by the UPS device.
  3. Unplug the system unit and the peripheral devices.
  4. Plug the UPS device into the wall outlet.
  5. Plug the system unit into the UPS device.
  6. Plug the additional peripheral devices into the UPS.
  7. Power on the UPS device.
  8. Power on the system unit and the additionally protected peripherals.
  9. Verify that the system unit and each additionally protected device are functioning properly.

 

Observing the functionality of a UPS device

  1. Power on your system unit and allow it to boot into Windows 9x.
  2. Power on your additional peripheral devices.
  3. Unplug the UPS device.
  4. Record the results.

 

 

 

 

 

Review Questions

Circle True or False.

  1. An in-line UPS can provide continuous power without downtime for switching from AC to battery. True / False
  2. A power conditioner will provide battery power for only five minutes in the case of an outage.
  1. True / False
  2. If a computer is protected by a standby UPS, the computer will most likely reboot if there is a power outage. True / False
  3. An intelligent UPS can be controlled by software. True / False
  4. Describe how a surge protector provides protection from power spikes.

 

 

 

 

 

 

 

 

 

 

  1. You are employed as a network administrator at Pictures, Inc. Your employer has asked you to assess the need for UPS devices for each of their 10 servers. After talking with the staff, you learn that seven of the servers are used for e-mail and bulletin board communications. The other three servers are used to maintain the company’s accounting inventory databases. Pictures, Inc. has asked that you provide two proposals for them: the first should outline the ideal protection plan, and the other should outline the minimum protection requirements.

 

Power Protection Plan A (ideal)

 

 

 

 

 

 

 

 

 

 

Power Protection Plan B (minimum requirements)

 

 

 

 

 

 

 

 

 

Lab Notes

7  What is an in-line UPS?—An in-line UPS is a device that continuously provides power through a battery-powered circuit. Because it requires no switching, it ensures continuous power to the user.

7  What is a standby UPS?—A standby UPS is a device that quickly switches from an AC power source to a battery-powered source during a brownout or power outage.

7  What is an intelligent UPS?—An intelligent UPS is connected to a computer by way of a serial cable so that software on the computer can monitor and control the UPS.

7  What is a power conditioner?—A power conditioner is a device that regulates, or conditions, the power, providing continuous voltage during brownouts.

 

Lab 8-6 How does a Power Supply Work

 

Go the webpage http://www.howstuffworks.com/power-supply1.htm and read the entire article on how Power Supplies work. In the box below, draw a computer power supply and label the components.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Answer the following questions:

 

  1. Define switcher technology.

 

 

 

 

  1. Where can you find information about your power supplies rating?

 

 

 

  1. Describe how advanced power management saves electricity.

 

 

 

 

 

  1. What are the form factors for power supplies?

 

 

 

  1. What are common power supply problems?

 

 

 

  1. How can you tell when a power supply has gone bad?

 

 

These questions will probably show up on the test!

 

 

Lab 8-7 Testing Power Supplies

 

Objectives

7  Identify some dangers involved in Power Supplies.

7  Identify and diagnose common power supply problems.

7  Test a power supply using a power supply tester.

7  Test connectors on the power supply.

 

Materials Required

7  Power supply

7  Power supply tester

7  Different connectors on power supply

7  Multimeter

 

Directions

  1. Get a power supply tester from me (check it out).
  2. Read the accompanying instructions on how to test your power supply.
  3. Get three power supplies from the cupboard. Do not plug it in!
  4. Test each of the power supplies in the following manner
    1. Test the P1 connection
    2. Test each of the molex connectors
    3. Test the ATX connector, if present
    4. Test each of the floppy connectors
  5. Fill out the table below

 

Power Supply Brand

Wattage rating

P1 test

# Molex connectors

Molex tests (pass/fail, note any that fail)

# ATX connectors

ATX test

# floppy connectors

Floppy connectors Test

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7  If any of the power supplies completely fails, throw it away (ensuring that you’ve tested others first to make sure you’re using the tester correctly).

 

7  If any of the power supplies has bad connectors but the P1 works, get a piece of tape and mark the bad connectors.

 

7  If any power supplies has all of a specific kind of connector fail, throw it away

 

  1. Now open up your lab computer, return your power supply tester, check out a multimeter.
  2. The first step in using the multimeter to perform tests is to select the proper function. For the most part, you never need to use the current function of the multimeter when working with computer systems; however, the voltage and resistance functions can be very valuable tools.
  3. In computer troubleshooting, most of the tests are DC voltage readings. These measurements usually involve checking the DC side of the power-supply unit. You can make these readings between ground and one of the expansion-slot pins, or at the system board power-supply connector.
  4. It is also common to check the voltage level across a system board capacitor to verify that the system is receiving power. The voltage across most of the capacitors on the system board is 5V (DC). The DC voltages that can normally be expected in a PC-compatible system are +12V, +5V, –5V, and –12V. The actual values for these readings may vary by 5% in either direction.

WARNING

Normal practice is to first set the meter to its highest voltage range to make certain that the voltage level being measured does not damage the meter.

 

10. The DC voltage function is used to take measurements in live DC circuits. It should be connected in parallel with the device being checked. In a PC system, this typically means connecting the reference lead (black lead) of the meter to a ground point and the measuring lead (red lead) to a test point to take a measurement, as illustrated in the figure below:

11. Note that on the side there is a label of what each of the cables in the P1 does.

12. Set your multimeter to DC volts 3.3. You’re telling it what you’re testing when you do this.

13. With the power off, connect the meter lead probe to the 3.3v connector on the power supply connector as shown in the second picture.

14. Connect the meter ground probe to the ground on P1.

15. Ensure that the multimeter is turned on and set to the correct settings. Set it down on the table with the probes in the power supply.

16. Plug in the power supply and turn it on. Without touching anything, write down the reading you get below:

 

17. Turn off the machine, unplug the power, remove the probes.

 

18. Do the same for the following positions and record the readings

 

Voltage

Reading

Voltage

Reading

Voltage

Reading

3.3

 

-5

 

5

 

12

 

-12

 

5

 

Remember to reset the multimeter each time to the proper reading.

Testing Resistance

1.      The second most popular test is the resistance test, or continuity test.

2.      Failure to turn off the power when making resistance checks can cause serious damage to the meter and can pose a potential risk to the technician. Resistance checks require that you electrically isolate the component being tested from the system. For most circuit components, this means desoldering at least one end from the board.

3.      The resistance check is very useful in isolating some types of problems in the system. One of the main uses of the resistance function is to test fuses. You must disconnect at least one end of the fuse from the system. You should set the meter on the 1 k ohm resistance setting. If the fuse is good, the meter should read near 0 ohms. If it is bad, the meter reads infinite. The resistance function also is useful in checking for cables and connectors. By removing the cable from the system and connecting a meter lead to each end, you can check the cable's continuity conductor by conductor to verify its integrity.

NOTE

4.      An electrical short is a condition where electrical current is given a path of flow around a designated component. In some cases, the short may be a complete bypass to a ground point so that no components receive current to operate with. On the other hand, an open is a condition that is created when no path for electrical current is present, such as when a connector comes loose or a component burns out.

5.      Get one of our older motherboards.

6.      Carefully locate a fuse and remove it.

7.      Set the meter to 1k ohm and test it.

8.      What is the reading?

 

Testing Speakers

9.      You also use the resistance function to test the system's speaker.

10. To check the speaker, simply disconnect it from the system and connect a meter lead to each end. If the speaker is good, the meter should read near 8 ohms (although a smaller speaker may be 4 ohms). If the speaker is defective, the resistance reading should be 0 for shorts or infinite for opens.

11. What reading did you get?

 

Only a couple of situations involve using the AC voltage function for checking microcomputer systems. The primary use of this function is to check the commercial power being applied to the power-supply unit. As with any measurement, it is important to select the correct measurement range; however, the lethal voltage levels associated with the power supply call for additional caution when making such measurements. The second application for the AC voltage function is to measure ripple voltage from the DC output side of the power-supply unit. This particular operation is very rarely performed in field-service situations. We’re not going to do it, lest we die.

 

Lab 8-8 Price and Value Comparisons

At your local computer vendor(s) or online compare the prices and ratings of three different surge suppressors.

 

Price

Rating

Company

Special Features

 

 

 

 

 

 

 

 

 

 

 

 

 

What is the purpose of a UPS?

 

 

 

 

 

Research the Market for a UPS for Your Computer System

For a computer system you have access to, determine how much wattage output a UPS should have in the event of a total blackout, and estimate how long the UPS should sustain the power. Research the market and report on the features and prices of a standby UPS and an inline UPS. Include the following information in your report:

. Wattage supported

 

. Length of time the power is sustained during total blackout

 

. Line-conditioning features

 

. AC backup present or not present for the inline UPS

 

. Ferroresonant transformer present or not present

 

. Surge suppressor present or not present

 

. Number of power outlets on the box and other features

 

. Written guarantees

 

. Brand name, model, vendor, and price of the device

 

 

Lab 8-9 PC Power Supply Facts

Remove the cover from your home or lab PC and answer the following questions:

  1. How many watts are supplied by your power supply? (It is usually printed on the label on the top of the power supply.)
  2. How many cables are supplied by your power supply?
  3. Where does each cable lead?
  4. Is there a switch on the back of the power supply that can be set for 220 volts (Europe) or 110 volts (U.S.)?

 

Lab 8-10 Total Wattage Used by Your Computer System

Fill in the following chart and then calculate the total wattage requirements of your computer system compared to the rating of your power supply. Include in the chart all devices that draw power from the power supply. Look for a wattage rating printed somewhere on the device.

 

Component

Wattage

Hard Drive

 

CD ROM

 

Floppy Drive

 

AGP Video Card

 

CPU

 

RAM

 

Motherboard

 

PCI Cards (multiply it by how many cards you have in your system)

 

Total Wattage

 

 

 

Total wattage requirements: __________________

 

Wattage rating of the power supply: ______________

 

This power supply is running at percent of full capacity. _____________

 

Why should you check this before you purchase your power supply?