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Instructors Guide

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SECOND EDITION

First Printing, July 2003

Copyright March, 2003 Lab-Volt Systems, Inc.

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i

Table of Contents

Section 1 Workstation Inventory and Installation............................................................... 1-1

Inventory of Workstation ........................................................................................................ 1-1

Minimum Computer Requirements.................................................................................... 1-1

Equipment and Supplies..................................................................................................... 1-1

Equipment Installation ............................................................................................................ 1-1

Software Installation ............................................................................................................... 1-1

Section 2 Introduction to F.A.C.E.T Curriculum................................................................ 2-1

Getting Started ........................................................................................................................ 2-2

Screen Buttons ........................................................................................................................ 2-3

F.A.C.E.T Help Screens and Resources.................................................................................. 2-4

Internet Access ........................................................................................................................ 2-5

Instructor Annotation Tool...................................................................................................... 2-5

Student Journal........................................................................................................................ 2-5

Assessing Progress .................................................................................................................. 2-6

Real-Number Questions and Answers .................................................................................... 2-8

Recall Values in Text ............................................................................................................ 2-10

Safety .................................................................................................................................... 2-11

Section 3 Courseware ............................................................................................................. 3-1

Unit 1 The AC Waveform Generator.................................................................................... 3-1

Exercise 1 AC Waveform Generator Familiarization.......................................................... 3-3

Exercise 2 Generator Impedance ......................................................................................... 3-6

Unit 2 AC Measurements ..................................................................................................... 3-11

Exercise 1 AC Amplitude Measurement............................................................................ 3-13

Exercise 2 Measuring With an Oscilloscope ..................................................................... 3-17

Exercise 3 Measuring and Setting Frequency.................................................................... 3-20

Exercise 4 Phase Angle...................................................................................................... 3-24

Unit 3 Inductance.................................................................................................................. 3-29

Exercise 1 Inductors........................................................................................................... 3-31

Exercise 2 Inductors in Series and in Parallel.................................................................... 3-36

ii

Unit 4 Inductive Reactance .................................................................................................. 3-49

Exercise 1 Inductive Reactance ......................................................................................... 3-50

Exercise 2 Series RL Circuits ............................................................................................ 3-57

Exercise 3 Parallel RL Circuits .......................................................................................... 3-62

Unit 5 Transformers ............................................................................................................. 3-71

Exercise 1 Transformer Windings ..................................................................................... 3-73

Exercise 2 Mutual Inductance............................................................................................ 3-78

Exercise 3 Transformer Turns and Voltage Ratios ............................................................ 3-81

Exercise 4 Transformer Secondary Loading...................................................................... 3-87

Unit 6 Capacitance................................................................................................................ 3-99

Exercise 1 Capacitors....................................................................................................... 3-101

Exercise 2 Capacitors in Series and in Parallel................................................................ 3-105

Unit 7 Capacitive Reactance .............................................................................................. 3-113

Exercise 1 Capacitive Reactance ..................................................................................... 3-114

Exercise 2 Series RC Circuits .......................................................................................... 3-121

Exercise 3 Parallel RC Circuits........................................................................................ 3-126

Unit 8 Time Constants ........................................................................................................ 3-135

Exercise 1 RC Time Constants ........................................................................................ 3-137

Exercise 2 RC and RL Wave Shapes ............................................................................... 3-142

Appendix A Pretest and Posttest Questions and Answers ................................................. A-1

Appendix B Faults and Circuit Modifications (CMs) .........................................................B-1

Appendix C Board and Courseware Troubleshooting....................................................... C-1

iii

Introduction

This Instructor Guide is divided into three sections and the appendices. It provides a unit-by-unit

outline of the Fault Assisted Circuits for Electronics Training (F.A.C.E.T) curriculum.

Section 1 Workstation Inventory and Installation contains a list and description of

equipment and materials required for all units in this course of study as well as installation

instructions.

Section 2 Introduction to F.A.C.E.T Curriculum provides a description of the courseware

structure, instructions on getting started with the multimedia presentation, and an explanation of

student-progress assessment methods.

Section 3 Courseware includes information that enables the instructor to gain a general

understanding of the units within the course.

The unit objective Unit Fundamentals questions and answers A list of new terms and words for the unit Equipment required for the unit The exercise objectives Exercise Discussion questions and answers Exercise Procedure questions and answers Review questions and answers CMs and Faults available Unit Test questions and answers Troubleshooting questions and answers (where applicable)

Appendices include the questions and answers to the Pretest and Posttest plus additional specific

information on faults and circuit modifications (CMs).

Please complete and return the OWNER REGISTRATION CARD included with the CD-

ROM. This will assist Lab-Volt in ensuring that our customers receive maximum support.

iv

THIS

SECTION 1 WORKSTATION INVENTORY

AND INSTALLATION

AC1 Fundamentals Section 1 Workstation Inventory and Installation

1-1

SECTION 1 WORKSTATION INVENTORY AND INSTALLATION

Inventory of Workstation

Use this section to identify and inventory the items needed.

Minimum Computer Requirements 100% compatible Windows

PC with Windows98 second edition or newer, NT, 2000, Me or XP;

Pentium class CPU, (Pentium II or newer); 126 MB RAM; 10 GB HDD; CD-ROM drive; SVGA

monitor and video card capable of 32-bit color display at 1024 x 768 resolution and sound

capabilities.

Equipment and Supplies The following equipment and supplies are needed for AC1 Fundamentals:

Quantity Description

1 F.A.C.E.T. base unit

1 AC 1 FUNDAMENTALS circuit board

1 Multimeter

1 Oscilloscope, dual trace

1 Generator, sine wave

1 Student Workbook

1 Instructor Guide

Equipment Installation

To install the hardware, refer to the Tech-Lab (minimum version 6.x) Installation Guide.

Software Installation

Third Party Application Installation

All applications and files that the courseware launches, or that are required for the course should

be installed before the courseware. Load all third party software according to the manufacturers'

directions. Install this software to the default location and note that location. (Alternatively, you

can install this software to a different location that you designate.) Remember to register all

software as required.

No third-party software is required for this course.

Installation of Courseware and Resources

To install the courseware and resources, refer to the Tech-Lab (minimum version 6.x) and

Gradepoint 2020 (minimum version 6.x) Installation Guide.

AC1 Fundamentals Section 1 Workstation Inventory and Installation

1-2

SECTION 2 INTRODUCTION TO F.A.C.E.T

CURRICULUM

AC1 Fundamentals Section 2 Introduction to F.A.C.E.T Curriculum

2-1

SECTION 2 INTRODUCTION TO F.A.C.E.T CURRICULUM

Overview F.A.C.E.T curriculum is multimedia-based courseware. The curriculum gives students hands-on

experience using equipment and software closely associated with industry standards. It provides

students with opportunities for instruction in academic and technical skills.

All courses are activity-driven curricula. Each course consists of several units containing two or

more exercises. Each unit begins with a statement explaining the overall goal of the unit (Unit

Objective). This is followed by Unit Fundamentals. Next is a list of new terms and words then

the equipment required for the unit. The exercises follow the unit material. When students

complete all the exercises, they complete the Troubleshooting section and take the Unit Test.

The exercises consist of an exercise objective, exercise discussion, and exercise procedures. The

Exercise Conclusions section provides the students with a list of their achievements. Every

exercise concludes with Review Questions. Available circuit modifications (CMs) and faults are

listed after the review questions. Additional specific information on CMs and faults is available

in Appendix B.


2-2

Getting Started

Desktop

After the Tech-Lab System is installed, the TechLab icon appears on the desktop.

1. Click on the TechLab icon.

2. The student clicks on LOGON and selects his or her name.

3. The student enters his or her password and clicks on OK. (If he or she is creating a password,

four alphanumeric characters must be entered. The system will ask for the password to be

entered again for verification. Keep a record of the students' passwords.)

4. The previous two steps are repeated until all members of the student team have logged on.

Click on Complete and then Yes.

5. When the Available Courses menu appears, students click on the course name.

6. A window with the name of the course and a list of units for that course appears. Students

click on the unit name. The unit title page appears and the students are ready to begin.

Selecting Other Courses and Exiting the Courseware

1. Clicking on Exit when in a unit returns the student to the list of units for that course.

2. If students wish to select another unit, they click on it.

3. If students wish to exit F.A.C.E.T, they click on the X symbol in the upper right corner.

4. If students wish to select another course, they click on the Course Menu button. The

Available Courses menu screen appears. They may also exit F.A.C.E.T from this screen by

clicking on the LOGOFF button.


2-3

Screen Buttons

If you click on the F.A.C.E.T logo on the top right of the unit title page the About screen

appears. It acknowledges the copyright holder(s) of video and/or screen-capture material used in

the topic.

The Menu button calls these menus:

when on an exercise menu screen, it calls the Unit Menu.

when on an exercise screen, it calls the Exercise Menu.

when on a unit screen, it calls the Unit Menu.

The Bookmark button marks the current screen. A student can click on the button at any time in

the lesson. The second time the student clicks on the button, the page displayed when the button

was first clicked will return to the screen. Any bookmarks used during a lesson are not saved

when the student logs out of the lesson.

The Application Launch button opens third-party software.

Click on the Resources button to view a pop-up menu. The pop-up menu includes access to a

calculator, a student journal, new terms and words, a print current screen option, the Lab-Volt

authored Internet Website, and a variety of F.A.C.E.T help screens.

The Help button aids students with system information. On certain screens the Help button

appears to be depressed. On these screens, clicking on the Help button will access Screen Help

windows (context-sensitive help).

The Internet button opens an Internet browser. Students will have unrestricted access to all

search engines and web sites unless the school administration has restricted this usage.

Use the Exit button to exit the course.

The right arrow button moves you forward to the next screen. The left arrow button moves you backward to the previous screen.


2-4

F.A.C.E.T Help Screens and Resources

There are three ways to access F.A.C.E.T help screens and other resources.

System Help Students access System Help by clicking on the Help button at the bottom of the screen when the

button does not appear to be depressed. The menu selections access a variety of system help,

navigation, and information windows.

Screen Help On certain screens, the Help button appears to be depressed. On these screens, clicking on the

Help button will access Screen Help windows. This is information specific to the content of that

particular screen.

Resources Students click on the Resources button to access the following windows.

Calculator

F.A.C.E.T 32-Bit Microprocessor Help

F.A.C.E.T Analog Communications Setup Procedure

F.A.C.E.T Digital Communications Help

F.A.C.E.T Electronics and Troubleshooting Help

F.A.C.E.T Fiber Optic Communications Help

F.A.C.E.T Math Help

Internet Link

New Terms and Words

Print Current Page

Student Journal


2-5

Internet Access

There are two ways for students to access the Internet:

The Internet button opens an Internet browser. Students have unrestricted access to all search

engines and websites unless the school administration has restricted this usage.

The Resources button pops up a menu that includes access to the Lab-Volt

authored Internet website. If students wish to access this site when they are not in

the lesson, then they must go to http://learning.labvolt.com.

NOTE: The Lab-Volt Internet site does not have content-filtering

software to block access to objectionable or inappropriate

websites.

Instructor Annotation Tool

The annotation tool gives the instructor the ability to add comments or additional information

onscreen. Refer to the Tech-Lab and GradePoint 2020 Installation Guide for detailed

information.

Student Journal

The student journal is an online notebook that each student can access while they are logged into

TechLab. The journal allows students to share notes with other students in their workgroups.

When used in conjunction with GradePoint 2020, the instructor may post messages, review, edit,

or delete any journal note.


2-6

Assessing Progress

Assessment Tools

Student assessment is achieved in several ways:

Exercise questions Unit tests Pretest and Posttest Troubleshooting questions

Exercise and Troubleshooting Questions

Throughout the unit material, exercise discussion, exercise procedure, and troubleshooting

sections there are several types of questions with instant feedback. These questions occur in the

following formats:

Multiple choice True-false Real-number entry

In most cases, when your students encounter a question set, they must answer these questions

before continuing. However, there are cases where students may progress to the next screen

without answering the questions. Lab-Volt recommends that you encourage your students to

complete all questions. In this way, students reinforce the material that's presented, verify that

they understand this material, and are empowered to decide if a review of this material is

required.

Review Questions

At the end of each exercise, there are review questions. The student receives feedback with each

entry. Feedback guides the student toward the correct answer.

Unit Tests

A unit test appears at the end of each unit. The test consists of 10 multiple-choice questions with

the option of having feedback. The Tech-Lab System defaults to no feedback, but the instructor

can configure the test so that students receive feedback after taking the test. You can randomize

questions in the unit test. Use the Tech-Lab Global Configurator to make feedback available,

randomize questions, and select other configuration options if desired. Refer to the Tech Lab

Quick-Start Guide for detailed information.


2-7

Pretest and Posttest

Every course includes a pretest and a posttest. These are multiple choice tests. Refer to the Tech

Lab Quick-Start Guide for detailed information on how to record student competency gains.

Grading

Student grades are based on exercise questions, troubleshooting questions, a unit test, and a

posttest. The default weighting value of the unit test and the threshold for passing the unit test

can be adjusted by using the Global Configurator of the Tech-Lab System. Refer to the Tech Lab

Quick-Start Guide for detailed information.

Student Progress and Instructor Feedback

Unit progress is available through the Unit menu. The Progress window allows the instructor and

student to view the percentage of the unit completed, number of sessions, and time spent on that

unit. The Progress window shows whether the Unit Test was completed. If the test was

completed, it indicates whether the student passed based on the scoring criteria.


2-8

Real-Number Questions and Answers

Throughout F.A.C.E.T courses students may encounter real-number questions such as the one

shown below. Answers to real-number questions are graded correct if they fall within an

acceptable tolerance range.

The answer to the question posed in the illustration above does not involve a recall value from a

previous question. It appears in the Instructor Guide (IG) as shown in the box below.

The information in the IG tells you where the question is located and the range of acceptable

answers. In this case, the acceptable answers fall within the range of the nominal answer plus or

minus 5 percent tolerance: (15 5%).

Location: Exercise Procedure page:

se1p1, Question ID: e1p1a

VS = Vdc

Recall Label for this Question: V1

Nominal Answer: 15.0

Min/Max Value: (14.25) to (15.75)

Value Calculation: 15.000

Correct Tolerance Percent = true

Correct Minus Tolerance = 5

Correct Plus Tolerance = 5

This is the name the computer uses internally

to identify the input value. In this case, 14.5

will be stored under the name V1.

NOTE: The recall value V1 is not the same as

the voltage V1. The recall label does not

appear onscreen.

In this case, the answer to this question is not

based on a value recalled from a previous

question. Therefore, the Value Calculation is

equal to the Nominal Answer.

The word "true" tells you that the tolerance is

calculated as a percent.

e1p1 stands for

Exercise 1 Procedure screen 1

The computer

saves this input

value so that it can

be recalled for use

in later questions.


2-9

A second example (shown below) illustrates an answer that the computer grades using a value

recalled from a previous question.

When a real-number question is based on a recall value from a previous question, the Min/Max

Value shown in the Instructor Guide is based upon a calculation using the lowest and highest

possible recall value. It represents the theoretical range of answers that could be accepted by the

computer. (It is not the nominal answer plus or minus the tolerance.)

To find the actual range of answers that the computer will accept onscreen, you must use the

actual recall value (14.5 in this example) in your calculations; see below.

NOTE: After four incorrect answers, students will be prompted to press to insert the

correct answer if this feature has been enabled in the configuration settings. When the question is

based on a value recalled from a previous question, answers obtained using the Insert key may

not match the nominal answers in this guide.

Location: Exercise Procedure page:

se1p5, Question ID: e1p5c

IT = mA

Recall Label for this Question: I1

Nominal Answer: 9.091 *Min/Max Value: (6.477) to (11.93)

Value Calculation: #V1#/1650*1000




Since the value for #V1# is 14.5, the

computer will accept answers in the

following range as correct:

14.5/1650*1000 25% or

8.79 25% or

6.59 to 10.99

This calculated range is different from the

Min/Max Value shown in the IG, which

was based upon a calculation using the

lowest and highest possible recall value.

Any letter enclosed in "#" signs refers to a

recall value from a previous question.


2-10

Recall Values in Text

Sometimes numbers displayed on screen are values recalled from input on previous screens.

Because these numbers are recall values, they will change for each student.

The Instructor Guide lists the recall label in place of a number in this question.

The value of 10

was recalled

from a previous

screen.

Location:Exercise Procedure page: se1p11, Question ID: e1p11c

IR2 = VR2/R2

= #V4#/3.3 k = mA

Recall Label for this Question: I1


Min/Max Value: (2.489) to (3.164)

Value Calculation: #V4#/3.3




This is a

recall label

for a value

recorded in a

previous

question.

The correct

answer will

depend on the

value the student

recorded in the

previous question.


2-11

Safety

Safety is everyones responsibility. All must cooperate to create the safest possible working

environment. Students must be reminded of the potential for harm, given common sense safety

rules, and instructed to follow the electrical safety rules.

Any environment can be hazardous when it is unfamiliar. The F.A.C.E.T computer-based

laboratory may be a new environment to some students. Instruct students in the proper use of the

F.A.C.E.T equipment and explain what behavior is expected of them in this laboratory. It is up to

the instructor to provide the necessary introduction to the learning environment and the

equipment. This task will prevent injury to both student and equipment.

The voltage and current used in the F.A.C.E.T Computer-Based Laboratory are, in themselves,

harmless to the normal, healthy person. However, an electrical shock coming as a surprise will

be uncomfortable and may cause a reaction that could create injury. The students should be made

aware of the following electrical safety rules.

1. Turn off the power before working on a circuit.

2. Always confirm that the circuit is wired correctly before turning on the power. If required,

have your instructor check your circuit wiring.

3. Perform the experiments as you are instructed: do not deviate from the documentation.

4. Never touch live wires with your bare hands or with tools.

5. Always hold test leads by their insulated areas.

6. Be aware that some components can become very hot during operation. (However, this is not

a normal condition for your F.A.C.E.T. course equipment.) Always allow time for the

components to cool before proceeding to touch or remove them from the circuit.

7. Do not work without supervision. Be sure someone is nearby to shut off the power and

provide first aid in case of an accident.

8. Remove power cords by the plug, not by pulling on the cord. Check for cracked or broken

insulation on the cord.


2-12

SECTION 3 COURSEWARE

SECTION 3 COURSEWARE

AC1 Fundamentals Unit 1 The AC Waveform Generator

3-1

UNIT 1 THE AC WAVEFORM GENERATOR

UNIT OBJECTIVE

Operate a basic ac waveform generator by using equipment provided.

UNIT FUNDAMENTALS

Location: Unit Fundamentals page: sf4, Question ID: f4a

Is the waveform shown an ac or dc waveform?

a. ac

b. dc


Does this ac waveform (square wave) display four complete cycles of a repeating pattern?

a. yes

b. no

CMS AVAILABLE

None

FAULTS AVAILABLE

None


3-2

NEW TERMS AND WORDS

alternating current (ac) - a flow of electricity that first increases to maximum, then decreases to

zero, reverses polarity, and reaches maximum in the opposite direction.

waveform - the shape of an electric wave as the amplitude is graphed over time.

amplitude - the level, or magnitude, of an alternating voltage or current.

cycle - one complete alternation of an ac current or voltage.

frequency (f) - the number of complete cycles in one second of alternating voltage or current;

measured in hertz (Hz).

impedance (Z) - the total opposition a circuit offers to the flow of alternating current at a given

frequency.

ac waveform generator - an electronic device that produces ac voltage of a desired frequency,

wave shape, and amplitude.

EQUIPMENT REQUIRED

F.A.C.E.T. base unit

AC 1 FUNDAMENTALS circuit board

Multimeter

Oscilloscope, dual trace

Generator, sine wave


3-3

Exercise 1 AC Waveform Generator Familiarization

EXERCISE OBJECTIVE

Operate an ac waveform generator by using equipment provided. Verify results by observing

generator waveforms on the oscilloscope.

EXERCISE DISCUSSION

Location: Exercise Discussion page: se1d2, Question ID: e1d2a

Suppose the range of control is set to X100 and the frequency control is set to 20. The output

frequency is

a. 200 Hz

b. 2000 Hz

c. 20 kHz


Look at the generator symbols on the AC 1 FUNDAMENTALS circuit board. Is the waveform

generator internal or external?

a. internal generator

b. external generator

EXERCISE PROCEDURE

Location: Exercise Procedure page: se1p1, Question ID: e1p1a

While observing the oscilloscope, increase the generator frequency control. Does the number of

cycles displayed increase or decrease as the frequency is increased?

a. increase

b. decrease


3-4

REVIEW QUESTIONS

Location: Review Questions page: se1r1, Question ID: e1r1

1. The controls that adjust frequency on an ac generator are the frequency and

a. range controls.

b. amplitude controls.

c. function controls.

d. vertical controls.


2. When the range (multiplier) control of a generator is set to X10 and the frequency control is

set to 20, the output frequency is

a. 2000 Hz.

b. 20 Hz.

c. 200 Hz.

d. 20,000 Hz.


3. The amplitude control on an ac generator is usually labeled

a. MULTIPLIER.

b. FUNCTION.

c. RANGE.

d. LEVEL.


4. Which statement is not characteristic of a typical ac generator?

a. All are capable of generating ac waveforms.

b. All can vary the frequency of the waveform produced.

c. All can vary the amplitude of the waveform produced.

d. All are capable of generating a dc waveform.


5. When the range (multiplier) control of a generator is set to X1K and the frequency control is

set to 10, the output frequency is

a. 1000 Hz.

b. 10 kHz.

c. 100 Hz.

d. 1.0 kHz.


3-5

CMS AVAILABLE

None

FAULTS AVAILABLE

None


3-6

Exercise 2 Generator Impedance

EXERCISE OBJECTIVE

Determine the output impedance of an ac waveform generator. Verify results with an

oscilloscope.

EXERCISE DISCUSSION


If RL decreased in value from 100 to 50, would the output voltage across RL increase or decrease?

a. increase

b. decrease


VOPEN CIRCUIT = Vpk-pk

Recall Label for this Question: None


Min/Max Value: (9.9) to (10.1)






To measure the generator output impedance, adjust RL so that the loaded generator output

voltage is half of the open circuit voltage output. Is the output load resistance (RL) equal to the

internal generator resistance (RS)?

a. yes

b. no


3-7

EXERCISE PROCEDURE


5. Connect the channel 1 (X10) probe across R1 and R2. Do R1 and R2 represent the generator's

load (RL)?

a. yes

b. no


RL =



Min/Max Value: (35) to (65)





REVIEW QUESTIONS


1. The load (RL) equals the output impedance (RS) of the generator when the

a. loaded output voltage equals the open circuit output voltage.

b. loaded output voltage is half of the open circuit output voltage.

c. open circuit output voltage is half of the loaded output voltage.

d. loaded output voltage is twice the open circuit output voltage.


2. The loaded output voltage of a generator is always

a. greater than the open circuit voltage.

b not dependent on the open circuit voltage.

c. equal to the open circuit voltage.

d. less than the open circuit voltage.


3-8


3. A 50 load resistor is connected to a generator with an open circuit voltage of 10 Vpk-pk and an output impedance of 50. The generator's output voltage is a. 10 Vpk-pk.

b. 5 Vpk-pk.

c. 20 Vpk-pk.

d. 3.3 Vpk-pk.


4. A generator has an open circuit voltage of 10 Vpk-pk and an output impedance of 600. What value of external load resistor would result in a 5 Vpk-pk output?

a. 600 b. 30 c. 60 d. 300


5. The output impedance of the generator shown is

a. 600. b. 60. c. 500. d. 50.

CMS AVAILABLE

None

FAULTS AVAILABLE

None


3-9

UNIT TEST

Depending on configurator settings, these questions may be randomized onscreen.

Location: Unit Test Question page: sut1, Question ID: ut1

Alternating voltage and current differ from direct voltage and current because alternating voltage

and current

a. maintain a constant polarity.

b. change in level and polarity.

c. never change level or polarity.

d. are not measured in volts or amperes.


One complete repetition of an ac waveform is called

a. the amplitude.

b. a cycle.

c. the frequency.

d. polarity.


If a 20 kHz sine wave is needed on the output of an ac generator and the multiplier control is set

to X100, the frequency control should be set to

a. 20.

b. 10.

c. 100.

d. 200.


A generator has an open circuit voltage of 5 Vpk-pk and an output impedance of 50. What value of external load resistor would result in a 2.5 Vpk-pk output?

a. 50 b. 25 c. 5 d. 500


A 600 load resistor is connected to a generator with an open circuit voltage of 20 Vpk-pk and an output impedance of 600. The generator's output voltage isa. 20 Vpk-pk.

b. 25 Vpk-pk.

c. 10 Vpk-pk.

d. 6.6 Vpk-pk.


3-10


What type of waveform does not change polarity with time?

a. sine wave

b. square wave

c. dc wave

d. triangle wave


The controls that adjust frequency on an ac generator are the frequency and

a. amplitude controls.

b. multiplier controls.

c. function controls.

d. vertical controls.


When the loaded output voltage of a generator is half of the open circuit output voltage, the

external load is

a. much greater than the output impedance of the generator.

b. twice the output impedance of the generator.

c. half of the output impedance of the generator.

d. equal to the output impedance of the generator.


Which control on a generator determines the type of output waveform?

a. amplitude

b. function

c. range

d. frequency


Which control on a generator adjusts the level of the output waveform?

a. function

b. frequency

c. amplitude

d. range

AC1 Fundamentals Unit 2 AC Measurements

3-11

UNIT 2 AC MEASUREMENTS

UNIT OBJECTIVE

Take amplitude, frequency, and phase measurements of ac waveforms by using an oscilloscope.

UNIT FUNDAMENTALS


Which of the following ac instruments can be used to measure the amplitude, frequency, and

phase shift of ac waveforms?

a. multimeter

b. oscilloscope


As in a circle, one complete cycle of a sine wave equals 360 degrees. One fourth of a cycle is

a. 180 degrees.

b. 90 degrees.

c. 270 degrees.

CMS AVAILABLE

None

FAULTS AVAILABLE

None


3-12

NEW TERMS AND WORDS

phase angle - the angle of separation between two ac waveforms of identical frequency.

peak-to-peak value - amplitude between opposite peaks of an ac waveform

(Vpk-pk = Vpk x 2).

peak value - maximum amplitude in either polarity of an ac waveform

(Vpk = Vpk-pk/2).

effective value (rms) - an ac value that produces the same heating effect in a resistor as an

equivalent dc value does.

average value (avg) - the value obtained by dividing the sum of a number of quantities by

the number of quantities. For sine waves, Vavg = 0.637 x Vpk.

period - time required for an ac waveform to complete one cycle (T = 1/f).

EQUIPMENT REQUIRED



Multimeter




3-13

Exercise 1 AC Amplitude Measurement

EXERCISE OBJECTIVE

Measure the amplitude of ac waveforms by using an oscilloscope. Verify results with a

multimeter.

EXERCISE DISCUSSION


If the peak-to-peak value is 15 Vpk-pk, the peak voltage is

a. 15 Vpk.

b. 30 Vpk.

c. 7.5 Vpk.


The rms value of a sine wave measuring 10 Vpk on an oscilloscope is

a. 7.07 Vac.

b. 7.07 Vpk-pk.

c. 7.07 Vpk.


The average value of a sine wave measuring 10 Vpk on an oscilloscope is

a. 6.37 Vpk.

b. 6.37 Vavg.

c. 12.7 Vavg.


Vrms = Vrms



Min/Max Value: (4.351) to (4.529)






3-14

EXERCISE PROCEDURE


Vpk-pk

Vpk = = Vpk

2

Recall Label for this Question: Vpk1

Nominal Answer: 3.0






Location: Exercise Procedure page: se1p2, Question ID: e1p2c

Vrms = Vpk x 0.707 = Vrms

Recall Label for this Question: Vrms1

Nominal Answer: 2.1






Location: Exercise Procedure page: se1p2, Question ID: e1p2e

Vavg = Vpk x 0.637 = Vavg

Recall Label for this Question: Vavg1

Nominal Answer: 1.9







3-15


8. Disconnect the X10 probe from the circuit. Turn on the multimeter and set it for ac voltage

measurement. Connect the multimeter across R1, then measure the voltage.

VR1 = Vac

Recall Label for this Question: Vrms2

Nominal Answer: 2.1







9. Compare your multimeter reading of #Vrms2#V with your oscilloscope values, shown above.

The multimeter displays values in

a. peak-to-peak.

b. peak.

c. rms.

REVIEW QUESTIONS


1. The effective value of an ac waveform is the

a. peak-to-peak value.

b. peak value.

c. rms value.

d. average value.


2. The peak value of an ac waveform is

a. twice the peak-to-peak value.

b. half of the peak-to-peak value.

c. 0.707 of the peak-to-peak value.

d. 0.637 of the peak-to-peak value.


3-16


3. The rms value of a sine wave is

a. half of the peak-to-peak value.

b. twice the peak value.

c. 0.637 of the peak value.

d. 0.707 of the peak value.


4. When measuring the peak-to-peak value of an ac waveform on the oscilloscope, measure from

the

a. top of a peak to the bottom of a valley.

b. top of a peak to the top of a valley.

c. bottom of a peak to the top of a valley.

d. bottom of a peak to the bottom of a valley.


5. Most digital multimeters display the

a. peak-to-peak value of a sine wave.

b. peak value of a sine wave.

c. rms value of a sine wave.

d. average value of a sine wave.

CMS AVAILABLE

None

FAULTS AVAILABLE

None


3-17

Exercise 2 Measuring With an Oscilloscope

EXERCISE OBJECTIVE

Measure voltage by using an oscilloscope and determine current and impedance by using Ohm's

law. Verify results with information found in this exercise.

EXERCISE DISCUSSION


The circuit shown uses 10 resistor R2 as the current-sensing resistor. If the voltage across R2 is 50 mVpk-pk, what is the circuit current?

I = V/R2 = mApk-pk

Recall Label for this Question: IT

Nominal Answer: 5.0







Placing the oscilloscope input directly across a component, as shown,

a. shorts out R2 and L2.

b. provides an accurate circuit voltage display.


3-18

EXERCISE PROCEDURE


I = mApk-pk



Min/Max Value: (12.04) to (22.36)






VR1 = Vpk-pk


Nominal Answer: 8.0






REVIEW QUESTIONS


1. The oscilloscope measures

a. voltage only.

b. voltage and current only.

c. voltage, current, and impedance.

d. current only.


2. The oscilloscope ground clip and the generator common

a. are independent of one another.

b. are of opposite polarity.

c. are virtually the same point.

d. cannot be connected together.


3-19


3. To measure, with an oscilloscope, the voltage drop across an ungrounded component in a

system with common grounds,

a. place the probe directly across the component being measured.

b. use the ALT-INVERT method.

c. place the probe in series with the component being measured.

d. use the ADD-INVERT method.


4. To measure circuit current with the oscilloscope,

a. use a current-measuring inductor.

b. place the probe in series with the circuit.

c. use a current-sensing resistor.

d. divide the source voltage by the generator impedance.


5. To determine circuit impedance,

a. divide the source voltage by the measured circuit current.

b. measure directly with a multimeter.

c. divide the source voltage by the generator impedance.

d. assume it is always a constant 50.

CMS AVAILABLE

CM 7 TOGGLE

FAULTS AVAILABLE

None


3-20

Exercise 3 Measuring and Setting Frequency

EXERCISE OBJECTIVE

Measure and set frequency by using an oscilloscope. Verify results with information found in

this exercise.

EXERCISE DISCUSSION


To set the generator frequency to 100 Hz, adjust the frequency control on the generator so that

the period (T) of the waveform trace on the oscilloscope equals

a. 1 ms.

b. 10 ms.

c. 10 .


A waveform trace on the oscilloscope has a measured period of 0.7 ms. The frequency is

a. 1.43 kHz.

b. 1.42 Hz.

c. 14.3 kHz.


3-21

EXERCISE PROCEDURE


4. Set the time base control on the oscilloscope to 0.1 ms/div. Adjust the frequency of the

generator for a waveform cycle that is seven divisions wide along the horizontal axis (time axis).

T (period) = ms

Recall Label for this Question: T

Nominal Answer: 0.7







1

f = = Hz

T

Recall Label for this Question: f


Min/Max Value: ( 1000) to ( 1858)






6. Compare your calculated value of frequency (#f# Hz) with the frequency read from the dial of

the generator. The two frequencies do not agree. What method do you think results in the closest

setting of the correct frequency?

a. generator dial

b. oscilloscope (period)


3-22

REVIEW QUESTIONS


1. The period (T) of a waveform is

a. equal to the frequency.

b. the reciprocal of the amplitude.

c. the reciprocal of the frequency.

d. unrelated to the frequency.


2. The frequency of a waveform is

a. equal to the period.

b. unrelated to the period.

c. the reciprocal of the period.

d. unrelated to time.


3. What is the period of a 2 kHz sine wave?

a. 2 ms

b. 200 s

c. 5 ms

d. 500 s


4. What is the frequency of a sine wave having a period of 250 s?

a. 4 kHz

b. 2.5 kHz

c. 250 Hz

d. 5 kHz


5. The period is the

a. number of waveform cycles that occur in one second.

b. time it takes a waveform to go from maximum positive value to maximum negative value.

c. time it takes a waveform to complete one cycle.

d. time it takes a waveform to go from maximum positive value to zero amplitude.


3-23

CMS AVAILABLE

None

FAULTS AVAILABLE

None


3-24

Exercise 4 Phase Angle

EXERCISE OBJECTIVE

Measure phase angle by using an oscilloscope. Verify results with information found in this

exercise.

EXERCISE DISCUSSION


Suppose the channel 1 oscilloscope display is adjusted so that one cycle is exactly 8 divisions

wide. What is the phase angle between the two sine waves (use CH 1 as the reference)?

a. 80

b. 45


Is the sine wave displayed on CH 2 leading or lagging the reference sine wave displayed

on CH 1?

a. leading

b. lagging

EXERCISE PROCEDURE


6. Make certain the oscilloscope trigger source control is set to CH 1. Switch the vertical mode to

ALT. Set both channel ground references to the center graticule line. Is the phase angle between

the input (CH 1) and output (CH 2) waveforms approximately zero?

a. yes

b. no


7. Slowly turn potentiometer R2 completely counterclockwise (CCW). Did a phase shift occur?

a. yes

b. no


3-25


8. Switch the vertical mode to CH 1 (display CH 1 only), and adjust the time base and variable

time base controls on the oscilloscope so that one cycle of the waveform is exactly 8 divisions.

How many degrees does each horizontal division represent?

a. 80

b. 45


Phase angle = (d)(45/div)

= degrees



Min/Max Value: (50.75) to (94.25)






11. Is the output (CH 2) waveform leading or lagging the reference (CH 1) waveform?

a. leading

b. lagging

REVIEW QUESTIONS


1. What waveform is usually used as a reference for measuring phase angle?

a. the output waveform

b. the input waveform

c. the line voltage waveform

d. the oscilloscope calibrator waveform


2. When the reference waveform is 8 divisions wide (horizontally) on the oscilloscope, how

many degrees does each division represent?

a. 90

b. 80

c. 45

d. 36


3-26


3. What is the phase angle between the two sine waves (use channel 1 as the reference)?

a. 45 lagging

b. 90 leading

c. 45 leading

d. 90 lagging


4. What is the phase angle between the two sine waves (use channel 1 as the reference)?

a. 90 leading

b. 90 lagging

c. 45 leading

d. 45 lagging


5. When you measure phase angle, both waveforms must be

a. of identical frequency.

b. of identical amplitude.

c. square waves.

d. different frequencies.

CMS AVAILABLE

None

FAULTS AVAILABLE

None


3-27

UNIT TEST



A sine wave has a period (T) of 1 ms. The frequency is

a. 1 ms.

b. 100 Hz.

c. 1000 Hz.

d. 10 ms.


One complete cycle of a sine wave equals

a. 360.

b. 270.

c. 180.

d. 90.


The degree of separation between two sine waves of the same frequency is the

a. amplitude.

b. period.

c. phase angle.

d. root mean square.


The time required for an ac waveform to complete one cycle is the

a. amplitude.

b. period.

c. phase angle.

d. root mean square.


The reciprocal value of the period equals the

a. phase angle.

b. peak value.

c. period.

d. frequency.


3-28


Measuring a waveform from the top of a peak to the top of a valley on the oscilloscope

accurately measures

a. peak-to-peak amplitude.

b. peak amplitude.

c. the effective value.

d. the waveform period.


The peak value of a 10 Vpk-pk sine wave is

a. 10.0 Vpk.

b. 5.0 Vpk.

c. 7.07 Vrms.

d. 6.36 Vavg.


The reciprocal value of the frequency equals the

a. frequency.

b. phase angle.

c. period.

d. peak current.


The peak value multiplied by 0.707 is the rms value of

a. sine waves only.

b. sine waves and square waves.

c. square waves only.

d. sine waves and triangle waves.


The oscilloscope directly measures

a. current only.

b. voltage and current.

c. voltage only.

d. voltage, current, and impedance.

AC1 Fundamentals Unit 3 Inductance

3-29

UNIT 3 INDUCTANCE

UNIT OBJECTIVE

Describe the effect of inductance on a circuit by using an oscilloscope.

UNIT FUNDAMENTALS


What type of circuit would produce the greatest cemf?

a. dc circuit

b. ac circuit


Which wire configuration would result in the greatest inductance value?

a. coil of wire

b. straight piece of wire


What value of inductance would result in a lower circuit current for any one frequency?

a. 5 mH

b. 10 mH

CMS AVAILABLE

None

FAULTS AVAILABLE

None


3-30

NEW TERMS AND WORDS

inductance (L) - one property of a conductor that opposes change in current flow.

counter electromotive force (cemf) - a voltage developed in an inductive circuit by alternating

current. The polarity of this voltage is, at every instant, opposite to that of the applied voltage.

inductor - a conductor, usually a coil of wire, wound to concentrate its magnetic field, which

produces a predicted measure of inductance.

henry (H) - unit of inductance. An inductance of one henry will produce one volt of cemf when

ac current of one ampere at one hertz is applied.

EQUIPMENT REQUIRED



Multimeter




3-31

Exercise 1 Inductors

EXERCISE OBJECTIVE

Describe the effect an inductor has on dc and ac circuits by using measured values. Verify results

with an oscilloscope and multimeter.

EXERCISE DISCUSSION


If inductance decreases, opposition to current flow will

a. increase.

b. remain the same.

c. decrease.

EXERCISE PROCEDURE


RL3 =

Recall Label for this Question: RL3meas








Idc = mA

Recall Label for this Question: Idcmeas








3-32


VL3dc = Vdc

Recall Label for this Question: VL3meas


Min/Max Value: ( .459) to ( .853)






RL3cal =

Recall Label for this Question: RL3cal


Value Calculation: (#VL3meas#)/(#Idcmeas#/1000)





9. Compare the coil resistance of RL3 (#RL3meas#), measured by using the resistance function of the multimeter and the calculated coil resistance of RL3cal (#RL3cal#). Based on this comparison, is inductor L3 producing cemf with constant dc current applied?

a. yes

b. no

* NOTE: Min/Max Values shown are based upon a calculation using the absolute lowest and

highest recall value. By using the actual input in your calculations, you will determine the correct

value.


3-33


Iac = VR2 /R2

= mApk-pk

Recall Label for this Question: Iac








VL3ac = Vpk-pk

Recall Label for this Question: VL3ac

Nominal Answer: 7.5







ZL3 =

Recall Label for this Question: ZL3

Nominal Answer: 595.2 *Min/Max Value: (310.9) to ( 1139)

Value Calculation: #VL3ac#/(#Iac#/1000)






value.


3-34


15. Compare the coil resistance of RL3 (#RL3meas#) and the calculated coil impedance ZL3 (#ZL3#). Based on this comparison, is L3 producing cemf when ac current is applied? a. yes

b. no


19. Does an increase of inductance increase or decrease circuit current?

a. increase

b. decrease


21. What is the effect of an increase in frequency on circuit current?

a. remains the same

b. decreases

c. increases


25. Does the circuit current lead or lag the inductor voltage?

a. lead

b. lag

REVIEW QUESTIONS


1. When constant dc is applied to an inductor, current flow is opposed by

a. cemf only.

b. coil resistance only.

c. cemf and coil resistance.

d. emf only.


2. When the CM is toggled off and on, what can you conclude about the inductance of L3 based

on the circuit current?

a. The inductance of L3 was reduced in value.

b. Changing the inductance of L3 had no effect on circuit current.

c. The inductance of L3 increased in value.

d. Changing the inductance of L3 decreased the circuit current.


3-35


3. Decreasing the frequency of the signal applied to an inductor

a. decreases current flow.

b. increases cemf.

c. neither increases nor decreases the current.

d. decreases impedance.


4. In an ideal inductor,

a. voltage leads current by 90.

b. current leads voltage by 90.

c. voltage lags current by 90.

d. voltage and current remain in phase.


5. An increase in cemf produced by an inductor is seen as

a. a decrease in voltage drop.

b. an increase in circuit current.

c. an increase in impedance.

d. a decrease in the coil resistance.

CMS AVAILABLE

CM 16 TOGGLE

CM 17 TOGGLE

FAULTS AVAILABLE

None


3-36

Exercise 2 Inductors in Series and in Parallel

EXERCISE OBJECTIVE

Determine the total inductance of a circuit containing inductors in series and in parallel. Verify

results with an oscilloscope.

EXERCISE DISCUSSION


LT = mH


Nominal Answer: 6.0







What is the total inductance (LT) in the above circuit?

a. 2 mH

b. 4 mH

c. 1 mH


3-37

EXERCISE PROCEDURE


LT = mH


Nominal Answer: 4.7

Min/Max Value: (4.653) to (4.747)






VR2

Iac =

R2

= mApk-pk

Recall Label for this Question: Iacc








VL3ac = Vpk-pk

Recall Label for this Question: VL3acc

Nominal Answer: 7.5







3-38


ZL3 =

Recall Label for this Question: ZL33


Value Calculation: #VL3acc#/(#Iacc#/1000)





LT = mH


Nominal Answer: 9.4

Min/Max Value: (9.212) to (9.588)






12. Did adding the inductor in series increase or decrease total circuit inductance (LT)?

a. increase

b. decrease


VR2

Iac = = mApk-pk

R2

Recall Label for this Question: Iac1

Nominal Answer: 7.6








value.


3-39


VLT = Vpk-pk

Recall Label for this Question: VLT


Min/Max Value: (6.272) to (11.65)






ZLT =

Recall Label for this Question: ZLT


Value Calculation: #VLT#/(#Iac1#/1000)





16. Compare your data from the two circuits. Which circuit offers the greatest opposition

(impedance) to current flow for the same signal input (VGEN)?

a. single inductor circuit

b. two-inductor series circuit


LT = mH



Min/Max Value: (2.28 ) to (2.421)







value.


3-40


VR2

Iac =

R2

= mApk-pk

Recall Label for this Question: Iac2


Min/Max Value: (11.97) to (22.23)






VL = Vpk-pk

Recall Label for this Question: VL

Nominal Answer: 5.0







ZL =

Recall Label for this Question: ZL


Value Calculation: #VL#/(#Iac2#/1000)






value.


3-41


23. Compare your data from the two circuits. Which circuit offers the greatest opposition

(impedance) to current flow for the same signal input (VGEN)?

a. single inductor circuit

b. two-inductor parallel circuit


24. While observing the oscilloscope, toggle the CM off and on by pressing . Based on the

circuit's current change, was the new inductor added to the circuit in series or in parallel with L3

and L4?

a. series

b. parallel

REVIEW QUESTIONS


1. The total inductance of inductors in series is

a. determined from the reciprocal method.

b. the sum of the inductor values divided by two.

c. the sum of the inductor values.

d. the reciprocal of the sum of the inductors.


2. The total inductance of inductors in parallel is

a. determined from the reciprocal method.

b. the sum of the inductor values.

c. the sum of the inductor values divided by two.

d. the reciprocal of the sum of the inductors.


3. As more inductors are added in parallel,

a. circuit current increases.

b. impedance increases.

c. circuit current decreases.

d. inductance increases.


3-42


4. As more inductors are added in series,

a. inductance decreases.

b. circuit current increases.

c. circuit current decreases.

d. impedance decreases.


5. Toggle the CM off and on by pressing . Based on the circuit current change, the unseen

inductor

a. was added in parallel.

b. had no effect on circuit current.

c. was added in series.

d. caused the circuit current to increase.

CMS AVAILABLE

CM 17 TOGGLE

CM 16 TOGGLE

FAULTS AVAILABLE

None


3-43

UNIT TEST



Inductance is the property of a conductor that

a. aids any change in current flow.

b. opposes change in current flow.

c. produces a magnetic field.

d. opposes unchanging current flow.


Increasing the number of turns on an inductor

a. decreases the inductance.

b. increases circuit current.

c. increases the inductance.

d. decreases impedance.


When dc is applied to an inductor, the only opposition to current flow is the

a. counter electromotive force (cemf).

b. changing impedance of the inductor.

c. frequency effect on the value of inductance.

d. resistance of the wire in the coil.


Two 10-mH inductors in parallel have a combined inductance of

a. 5.0 mH.

b. 20 mH.

c. 10 mH.

d. 3.3 mH.


A straight piece of wire has relatively little inductance because

a. it does not possess any inductive property.

b. the magnetic field is spread over a large area.

c. cemf is produced only in coils.

d. there is no core.


Increasing the frequency of the signal applied to an inductor

a. increases current flow.

b. increases the inductor impedance.

c. decreases the inductor impedance.

d. decreases the amount of cemf produced.


3-44


Two 7-mH inductors in series have a combined inductance of

a. 7 mH.

b. 3.5 mH.

c. 7.5 mH.

d. 14 mH.


Increasing the number of inductors in series

a. decreases total inductance.

b. increases circuit current.

c. increases impedance.

d. decreases cemf.


Increasing the number of inductors in parallel

a. decreases total inductance.

b. decreases circuit current.

c. increases impedance.

d. increases cemf.


The current in an inductor

a. leads the voltage by 45.

b. leads the voltage by 90.

c. lags the voltage by 90.

d. lags the voltage by 45.


3-45

TROUBLESHOOTING

Location: Troubleshooting page: ttrba2, Question ID: trba2a

Connect the channel 2 oscilloscope probe across R1, which is the output (VR1) of the full-wave

bridge rectifier. Are both alternations of the ac input waveform being rectified to dc pulses atthe

output?

a. yes

b. no

Location: Troubleshooting page: ttrba2, Question ID: trba2c

VR1 = Vdc



Min/Max Value: (6.237) to (7.623)





Location: Troubleshooting page: ttrba3, Question ID: trba3

6. The faulty component is

a. T1 (an open secondary coil).

FACET Circuitos 2 Parte 1

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Transcript of FACET Circuitos 2 Parte 1