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LABORATORY MANUAL

ECE 211 - Electrical Engineering Lab I

A companion course with

ECE 202 - Electric Circuits I

Clemson University

Holcombe Department of

Electrical and Computer EngineeringClemson, SC 29634

Revised

July 2010Dr. J. E. Harriss

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Clemson University ECE 211 Page ii July 2010 Edition

Revision Notes2005 Author: O. C. Parks. Revised from earlier editions.

2010 Revised April-May 2010 by Dr. James E. Harriss. Minor corrections (typos, table labels,

etc.). Revise Lab 2 for better introduction to the NI-ELVIS II. Reduce voltage in Lab 2,step 4 to avoid equipment damage. Revise Lab 10 for better clarity and to reducemeasurement errors. Changed terms throughout (especially Lab 8) to conform to NI-

ELVIS II. Change from PSpice to B2 Spice. Minor revision in Appendix C. AddRevision Notes.

2010 Revised July 2010 by Dr. James E. Harriss. Eliminate Lab 12 (Lab Review andPresentations) to reduce the number of lab meetings to better fit the semester schedule.

Change Lab 4 (B2 Spice) Procedure 4 to illustrate the effect of component tolerance oncircuit measurements. Move former Lab 5 (Statistical Analysis) to a later point in the

course.

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Clemson University ECE 211 Page iii July 2010 Edition

ContentsPart I Course Information..........................................................................................................iv

Introduction.........................................................................................................................vStudent Responsibilities:..................................................................................................v

Laboratory Teaching Assistant Responsibilities:..............................................................vFaculty Coordinator Responsibilities: ..............................................................................v

Lab Policy and Grading: .................................................................................................viCourse Goals and Objectives: .........................................................................................vi

Use of Laboratory Instruments ........................................................................................ viiiLaboratory Notebooks and Reports......................................................................................x

The Laboratory Notebook:...............................................................................................xThe Lab Report:...............................................................................................................x

Format of Lab Report: ....................................................................................................xiPart II Laboratory Meetings .......................................................................................................0

Laboratory 1 Orientation ...................................................................................................1Laboratory 2 Workstation Characteristics ..........................................................................2

Laboratory 3 DC Measurements ........................................................................................8Laboratory 4 Introduction to B2 Spice .............................................................................11

Laboratory 5 Network Theorems I ...................................................................................15Laboratory 6 Network Theorems II..................................................................................19

Laboratory 7 The Oscilloscope ........................................................................................21Laboratory 8 RC and RL Circuits ....................................................................................24

Laboratory 9 Series RLC Circuits ....................................................................................27Laboratory 10 Statistical Analysis ....................................................................................31

Laboratory 11 Design Lab ................................................................................................33Laboratory 12 Final Exam ................................................................................................35

Part III Appendices ..................................................................................................................36Appendix A: Safety ..........................................................................................................37

Appendix B: Fundamentals of Electrical Measurements ...................................................41Appendix C: Fundamentals of Statistical Analysis ............................................................50

Appendix D: Resistor Identification..................................................................................58

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Clemson University ECE 211 Page iv July 2010 Edition

Part I

Course Information

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Introduction

Clemson University ECE 211 Page v July 2010 Edition

Introduction

This course is intended to enhance the learning experience of the student in topics encountered in

ECE 202. In this lab, students are expected to get hands-on experience in using the basic

measuring devices used in electrical engineering and in interpreting the results of measurementoperations in terms of the concepts introduced in the first electrical circuits course. How the

student performs in the lab depends on his/her preparation, participation, and teamwork. Eachteam member must participate in all aspects of the lab to insure a thorough understanding of the

equipment and concepts. The student, lab teaching assistant, and faculty coordinator all havecertain responsibilities toward successful completion of the lab's goals and objectives.

S t udent R es pons i bi l i t i es :

The student is expected to be prepared for each lab. Lab preparation includes reading the lab

experiment and related textbook material. If you have questions or problems with the

preparation, contact your Laboratory Teaching Assistant (LTA), but in a timely manner. Don'twait until an hour or two before and then expect to find the LTA immediately available. Active

participation by each student in lab activities is expected. The student is expected to ask theteaching assistant any questions he/she may have. DO NOT MAKE COSTLY MISTAKES

BECAUSE YOU DID NOT ASK A SIMPLE QUESTION. A large portion of the student's gradeis determined in the comprehensive final exam, so understanding the concepts and procedure of

each lab is necessary for successful completion of the lab. The student should remain alert anduse common sense while performing a lab experiment. He/she is also responsible for keeping a

professional and accurate record of the lab experiments in a laboratory notebook. Studentsshould report any errors in the lab manual to the teaching assistant.

L a b o r a t o r y T e a c h i n g A s s i s t a n t R e s p o n s i b i l i ti es :

The Laboratory Teaching Assistant (LTA) shall be completely familiar with each lab prior to

class. The LTA shall provide the students with a syllabus and safety review during the first class.

The syllabus shall include the LTA's office hours, telephone number, and the name of the facultycoordinator. The LTA is responsible for insuring that all the necessary equipment and/or

preparations for the lab are available and in working condition. LAB EXPERIMENTS SHOULDBE CHECKED IN ADVANCE TO MAKE SURE EVERYTHING IS IN WORKING ORDER.

The LTA should fully answer any questions posed by the students and supervise the studentsperforming the lab experiments. The LTA is expected to grade the lab notebooks and reports in a

fair and timely manner. The reports should be returned to the students in the next lab periodfollowing submission. The LTA should report any errors in the lab manual to the faculty

coordinator.

F ac ul t y C oor di nat or R es pons i bi l i t i es :

The faculty coordinator should insure that the laboratory is properly equipped, i.e., that the

teaching assistants receive any equipment necessary to perform the experiments. The coordinatoris responsible for supervising the teaching assistants and resolving any questions or problems

that are identified by the teaching assistants or the students. The coordinator may supervise the

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Introduction

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format of the final exam for the lab. He/she is also responsible for making any necessarycorrections to this manual. The faculty coordinator is responsible for insuring that the software

version of the manual is continually updated and available.

L a b P o l i c y a n d G r a d i n g :

The student should understand the following policy:

ATTENDANCE: Attendance is mandatory and any absence must be for a valid excuse and mustbe documented. If the instructor is more than 15 minutes late, students may leave the lab.

LAB RECORDS: The student must:

1) Keep all work in preparation of and obtained during lab in an approved NOTEBOOK; and

2) Prepare a lab report on selected experiments.

GRADING POLICY: The final grade of this course is determined using the following criterion:

Laboratory notebook and in-class work: 40%

Lab reports: 40%

Final exam: 20%

In-class work will be determined by the teaching assistant, who, at his/her discretion may use

team evaluations to aid in this decision. The final exam should contain a written part and apractical (physical operations) part.

PRE-REQUISITES AND CO-REQUISITES: The lab course is to be taken during the same

semester as ECE 202, but receives a separate grade. If ECE 202 is dropped, then ECE 211 mustbe dropped also. Students are required to have completed both MTHSC 108 and PHYS 122 with

a C or better grade in each. Students are also assumed to have completed a programming classand be familiar with the use of a computer-based word processor.

THE INSTRUCTOR RESERVES THE RIGHT TO ALTER ANY PART OF THISINFORMATION AT HIS/HER DISCRETION IF CIRCUMSTANCES SHOULD DICTATE.

Any changes should be announced in class and distributed in writing to the students prior to theireffect.

C our s e G oal s and O bj ec t i v es :

The Electrical Circuits Laboratory I is designed to provide the student with the knowledge to use

basic measuring instruments and techniques with proficiency. These techniques are designed tocomplement the concepts introduced in ECE 202. In addition, the student should learn how to

record experimental results effectively and present these results in a written report. Moreexplicitly, the class objectives are:

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Introduction

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1) To gain proficiency in the use of common measuring instruments.

2) To enhance understanding of basic electric circuit analysis concepts including:

a) Independent and dependent sources.

b) Passive circuit components (resistors, capacitors, inductors, and switches).

c) Ohm's law, Kirchhoff's voltage law, and Kirchhoff's current law.

d) Power and energy relations.

e) Thvenin's theorem and Norton's theorem.

f) Superposition.

3) To develop communication skills through:

a) Maintenance of succinct but complete laboratory notebooks as permanent, written

descriptions of procedures, results, and analyses.

b) Verbal interchanges with the laboratory instructor and other students.

c) Preparation of succinct but complete laboratory reports.

4) To compare theoretical predictions with experimental results and to resolve any apparent

differences.

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Use of Laboratory Instruments

Clemson University ECE 211 Page viii July 2010 Edition


One of the major goals of this lab is to familiarize the student with the proper equipment and

techniques for making electrical measurements. Some understanding of the lab instruments is

necessary to avoid personal or equipment damage. By understanding the device's purpose andfollowing a few simple rules, costly mistakes can be avoided.

Ammeters and Voltmeters:

The most common measurements are those of voltages and currents. Throughout this manual, the

ammeter and voltmeter are represented as shown in Figure 1.

Figure 1 - Ammeter and voltmeter.

Ammeters are used to measure the flow of electrical current in a circuit. Theoretically, measuringdevices should not affect the circuit being studied. Thus, for ammeters, it is important that their

internal resistance be very small (ideally near zero) so they will not constrict the flow of current.However, if the ammeter is connected across a voltage difference, it will conduct a large current

and damage the ammeter. Therefore, ammeters must always be connected in series in a cir-cuit, never in parallel with a voltage source. High currents may also damage the needle on an

analog ammeter. The high currents cause the needle to move too quickly, hitting the pin at theend of the scale. Always set the ammeter to the highest scale possible, then adjust downward

to the appropriate level.

Voltmeters are used to measure the potential difference between two points. Since the voltmeter

should not affect the circuit, the voltmeters have very high (ideally infinite) impedance. Thus, thevoltmeter should not draw any current, and not affect the circuit.

In general, all devices have physical limits. These limits are specified by the device manufacturerand are referred to as the device rating. The ratings are usually expressed in terms of voltage

limits, current limits, or power limits. It is up to the engineer to make sure that in deviceoperation, these ratings (limit values) are not exceeded. The following rules provide a guidelinefor instrument protection.

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Clemson University ECE 211 Page ix July 2010 Edition

I nstrument Pr otection Rul es:

1) Set instrument scales to the highest range before applying power.

2) Be sure instrument grounds are connected properly. Avoid accidental grounding of "hot"leads, i.e., those that are above ground potential.

3) Check polarity markings and connections of instruments carefully before connecting power.

4) Never connect an ammeter across a voltage source. Only connect ammeters in series with

loads.

5) Do not exceed the voltage and current ratings of instruments or other circuit elements. This

particularly applies to wattmeters since the current or voltage rating may be exceeded with theneedle still on the scale.

6) Be sure the fuse and circuit breakers are of suitable value. When connecting electrical

elements to make up a network in the laboratory, it is easy to lose track of various points in thenetwork and accidently connect a wire to the wrong place. A procedure to follow that helps toavoid this is to connect the main series part of the network first, then go back and add the

elements in parallel. As an element is added, place a small check by it on your circuit diagram.Then go back and verify all connections before turning on the power. One day someone's life

may depend upon your making sure that all has been done correctly.

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Laboratory Notebooks and Reports

Clemson University ECE 211 Page x July 2010 Edition


T h e L a b o r a to r y N o t e b o o k :

The student records and interprets his/her experiments via the laboratory notebook and thelaboratory report. The laboratory notebook is essential in recording the methodology and results

of an experiment. In engineering practice, the laboratory notebook serves as an invaluablereference to the technique used in the lab and is essential when trying to duplicate a result or

write a report. Therefore, it is important to learn to keep an accurate notebook. The laboratorynotebook should

1) Be kept in a sewn and bound or spiral bound notebook.

2) Contain the experiment's title, the date, the equipment and instruments used, any pertinent

circuit diagrams, the procedure used, the data (often in tables when several measurements havebeen made), and the analysis of the results.

3) Contain plots of data and sketches when these are appropriate in the recording and analysis ofobservations.

4) Be, an accurate and permanent record of the data obtained during the experiment and theanalysis of the results. You will need this record when you are ready to prepare a lab report.

T he Lab R epor t :

The laboratory report is the primary means of communicating your experience and conclusions

to other professionals. In this course you will use the lab report to inform your LTA what you did

and what you have learned from the experience. Engineering results are meaningless unless theycan be communicated to others.

Your laboratory report should be clear and concise. The lab report shall be typed on a wordprocessor.As a guide, use the format on the next page. Use tables, diagrams, sketches, and plots,

as necessary to show what you did, what was observed, and what conclusions you draw fromthis. Even though you will work with one or more lab partners, your report will be the result of

your individual effort in order to provide you with practice in technical communication.

You will be directed by your LTA to prepare a lab report on a few selected lab experiments

during the semester. Your assignment might be different from your lab partner's assignment.

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Clemson University ECE 211 Page xi July 2010 Edition

F o r m a t o f L a b R e p o r t :

LABORATORY XX

TITLE

(Indicate the lab title and number)

NAME- Give your name.

LAB PARTNER(S) - Specify your lab partner's name. DATE - Indicate the date the lab was

performed.

OBJECTIVE- Clearly state the objective of performing the lab.

EQUIPMENT USED - Indicate which equipment was used in performing the experiment. Themanufacturer and model number should be specified.

PROCEDURE - Provide a concise summary of the procedure used in the lab. Include anymodifications to the experiment.

DATA - Provide a record of the data obtained during the experiment. Data should be retrievedfrom the lab notebook and presented in a clear manner using tables.

OBSERVATIONS AND DISCUSSIONS - The student should state what conclusions can bedrawn from the experiment. Plots, charts, other graphical medium, and equations should be

employed to illustrate the student's viewpoint. Sources of error and percent error should be notedhere.

QUESTIONS- Questions pertaining to the lab may be answered here. These questions may beanswered after the lab is over.

CONCLUSIONS - The student should present conclusions which may be logically deduced

from his/her data and observations.

SIGNATURE - Sign your report at the end. Include the statement - "This report is accurate to

the best of my knowledge and is a true representation of my laboratory results."

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Clemson University ECE 211 July 2010 Edition

Part II

Laboratory Meetings

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Laboratory 1: Orientation

Clemson University ECE 211 Page 1 July 2010 Edition

Laboratory 1

Orientation

Introduction:In the first lab period, the students should become familiar with the location of equipment and

components in the lab, the course requirements, and the teaching instructor. Students should alsomake sure that they have all of the co-requisites and pre-requisites for the course at this time.

Objective:

To familiarize the students with the lab facilities, equipment, standard operating procedures, labsafety, and the course requirements.

Preparation:

Read the introduction and Appendix A,Safety, in this manual.

Equipment Needed:

ECE 211 lab manual.

Procedure:

1) During the first laboratory period, the instructor will provide the students with a general idea

of what is expected from them in this course. Each student will receive a copy of the syllabus,stating the instructor's office hours and telephone number. In addition, the instructor will

review the safety concepts of the course.

2) The instructor will indicate which word processor should be used for the lab reports. Thestudents should familiarize themselves with the preferred word processor software.

3) During this period, the instructor will briefly review the equipment which will be used

throughout the semester. The location of instruments, equipment, and components (e.g.resistors, capacitors, connecting wiring) will be indicated. The guidelines for instrument use

will be reviewed.

Probing Further:

1) During the next period, the instructor may ask questions or give a quiz to determine if you

have read the introductory material. As a professional engineer, it will be your responsibility to

prepare yourself to do your job correctly. Learn as much as you can "up front. You will findthat as a practicing professional if you wait until the last minute, you might have to pay a verypainful price emotionally, financially, and professionally.

Report:

No report is due next time.

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Laboratory 2: Workstation Characteristics


Laboratory 2

Workstation Characteristics

Introduction:Every engineer relies on equipment to drive and measure an electrical system under study. These

devices are rarely ideal, and have their own internal characteristics which must be considered.The internal characteristics of various devices often have a significant effect on circuit operation.

This may be accounted for in circuit design and analysis to more adequately predict actualoperation in the lab. Students and engineers should understand the internal characteristics of the

equipment they are using. This experiment will explore some of those characteristics for the NI-ELVIS workstations used in this course.

Objective:

By the end of this lab, the student should know how to determine the internal resistance of

meters and sources. The student should understand how the internal resistance of theseinstruments affects the measurements.

Preparation:

Reading: Read the sectionUse of Lab instrumentsand Appendix B,Fundamentals of ElectricalMeasurement, in this manual.

Writing: In your laboratory notebook sketch the circuit diagram for each part of the procedure

and create tables formatted to enter your data.

Equipment Needed:

NI-ELVIS workstation.Resistance substitution box.Resistors: 1.0 k

Procedure:

Getting Started:

a. Turn on computer.

b. Turn on NI-ELVIS power switch (right corner on the back).

c. Turn on the NI-ELVIS Prototyping Board Power switch (at upper right corner, on top).

d. Launch NI-ELVISMXINSTRUMENTSprogram.

e. Launch the NI-ELVIS DMM instrument.f. Launch the NI-ELVIS VPS (Variable Power Supply) instrument.

g. Arrange the instruments on the computer screen for your convenience.

h. Set DMM to measure DC Volts. Specify the range to be 60V.

Note: The various range scales of voltmeters, ammeters, and similar measurementinstruments are achieved by changing the internal resistances of the instruments. Therefore,

when measuring the internal resistance of an instrument, it is important to set the

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instruments range to one value and not change it until the measurements are completed.Therefore, choose a scale that will allow making the desired measurements.

1) NULL OFFSETfor the voltmeter:

Electrical drift sometimes causes shifts in the ZERO point indicated by measurement

instruments. Often the shift is inconsequential, but sometimes it is significant compared tothe actual signal being measured. To eliminate the shift, the NI-ELVIS provides a N ULLOFFSETfunction that subtracts the value indicated at the instant N ULLOFFSETis turned on.

This is just like subtracting the tare weight of a container on a laboratory balance beforeweighing a material.

To set the voltmeters NULLOFFSET: Plug leads into the DMM V and COM jacks,clip the leads together, let the voltage reading stabilize, and turn on Null Offset.

2) Measure DC resistance of the DMM Voltmeter:

Voltmeters have an internal electrical resistance. Ideally a voltmeter would have infinite

resistance, so no current would flow through it and so the meter would not affect voltagesthroughout the circuit. But real meters are not ideal. In this exercise you will measure theDC resistance of the DMM voltmeter.

a. Set the VPS Supply + voltage to +10.00 Volts. STOP the VPS.

b. Set up the circuit as shown in Figure 2.1, using the NI-ELVIS DMM for the voltmeter

and the VPS for the power supply.

Figure 2.1 - Circuit diagram to measure the internal resistance of the voltmeter.

c. Set the resistor R to 0 by shorting the resistors leads. RUN the VPS and record the

voltage indicated by the meter. Remove the short across R.

d. Increase the resistance R so that the meter reading drops by a significant fraction (up to

about one half) of the original value. (Hint: R will need to be in the range of M.)Record the final resistance R and measured voltage.

e. STOP the VPS.

f. Use the DMM ohmmeter to measure the actual resistance R, rather than relying on the

indicated settings of the substitution box. Record the measured value. (Anytime you

+

10V V

R

Voltmeterwith internal

resistance RVi

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make such measurements, it may be instructive to record results at a few intermediatevalues of R as well, for corroborative calculations.)

g. From these readings, use voltage division to calculate RVi, the equivalent internalresistance of the voltmeter.

3) Measure DC resistance of the DMM Ammeter:Ammeters also have an internal electrical resistance. Ideally an ammeter would have no

resistance (0 ) so that it would not alter the current flow it is trying to measure. In this

exercise you will measure the DC resistance of the real DMM ammeter.

a. Set the VPS Supply + voltage to +10.00 Volts. RUN the VPS and measure the

actual voltage using the DMM voltmeter. Record the actual voltage. S TOP the VPS.

b. To use the DMM as an ammeter, move the DMM cables to A and COM and switch

the DMM to measure DC Amps.

c. Set up the circuit as shown in Figure 2.2, using the NI-ELVIS DMM for the ammeter

and the VPS for the power supply.

Figure 2.2 - Circuit diagram to measure the internal resistance of the ammeter.

d. With the VPS STOPPED, null the ammeter display value to obtain a reasonable zeroreading.

d. NULL the ammeter: Disconnect one lead of the ammeter (so no current will flow) andnull the ammeter display value to obtain a reasonable zero reading. Reconnect the

ammeter lead to the circuit.

e. Set the resistor R to 1 M resistance. RUN the VPS. In a table, record the resistance

R and the current indicated by the ammeter.

f. Adjust R to 100k. In your table, record the resistance R and the current indicated by

the ammeter.

g. Continue to decrease the resistance R until the ammeter reading drops by a significant

fraction (up to about one half) of the original value. Record the final resistance R andmeasured current.

+

10V A R

1k

Ammeter

with internal

resistance RAi

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h. Use the DMM ohmmeter to measure the actual final resistance R, rather than relying onthe indicated settings of the substitution box. (You will need to connect the DMM

cables to V and COM for this measurement.)

i. From these readings, use current division to calculate RAi, the equivalent internal

resistance of the ammeter.

4) Measure Output Resistance of VPS Supply +:

Power sources also have internal resistance, which cause the units to get hot and which limit

the amount of current the sources can deliver. The internal resistance may also be chosen tomatch a power source to the system it is powering. In this step you will measure the internal

resistance of the NI-ELVISs variable power supply, VPS.

a. STOPthe VPS.

b. Set the VPS Supply + voltage to +0.5 Volts.

c. Use the DMM to measure the actual voltage.

To do this, switch the DMM to DC V mode and choose AUTOMode. Move the DMMleads to V and COM and connect the DMM leads to SUPPLY+ output and

GROUND. RUN the VPS and measure the actual voltage with the DMM voltmeter.Record the actual voltage. STOP the VPS.

Note:If you null the voltmeter, be sure you do so by disconnecting the DMM leads from thecircuit and shorting the leads together. Even with the VPS STOPPED, a small but significant

voltage may exist.

d. Construct the circuit shown in Figure 2.3.

Figure 2.3 - Circuit diagram for measuring the internal resistance of theworkstation power supply.

e. Adjust the resistor R to 10k. RUN the VPS. Record the resistance R and themeasured voltage in a table.

f. Adjust the resistance R so that the meter reading drops by a significant fraction (up toabout one half) of the original value. Record the R and V values in the table.

CAUTION: The resistors in the substitution box are rated to handle at most 0.3 Watt power(Power = V/R). If you exceed that limit, you will likely damage both the resistors and the

power supply.

+

0.5VA

R

VPS

RVPS

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g. From these readings, use voltage division to determine RVPS, the equivalent internalresistance of the voltage source VPS.

5) Measure Output Resistance of the Function Generator:

Repeat Part 4 using the Function Generator FGEN instead of VPS for the power source.

a. Construct the circuit shown in Figure 2.4.

Figure 2.4 Circuit diagram to measure internal resistance of the

Function Generator FGEN.

b. Set the FGEN to output a sine wave with p-p amplitude of 1.41V and frequency

100 Hz.

c. Set the DMM to measure AC Volts. Keep in mind that the voltmeters display shows

the value of RMS voltage, where for a sinusoidal waveform,

2 2 2RMS

peak p pV VV

.

d. Adjust the resistor R to 100 k. RUN the FGEN. Record the resistance and the

measured voltage in a table.

e. Adjust the resistance R so that the meter reading drops by a significant fraction (up to

about one half) of the original value. Record the R and V values in the table.

f. From these readings, use voltage division to determine RFGEN, the equivalent internal

resistance of the Function Generator.

Probing Further:

1) Based on your estimates of the internal resistance of the voltmeters and ammeters used in

these experiments, what would be the values of internal resistance of these meters if, in each

case, the range used had been a factor of 10 larger than the range you actually used? Refer toAppendix B for the equivalent circuit models of the meters to guide your thinking about the

answer to this question.

2) Given your values for the internal resistances o f the DC source and the function generator,

what do you think is the maximum amount of current that can be supplied by each source?

V RVp-p=1.414 V

FunctionGenerator RFGEN

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3) How does the voltmeters resistance affect measurements? Consider the circuit shown inFigure 2.5, and assume that the power supply is ideal.

Figure 2.5 - Circuit diagram for measurements to determine the effect of

voltmeter internal resistance on measurement accuracy.

For resistance values R = 1k, 100k, and 10M, calculate the voltage that would be

displayed on an ideal voltmeter (i.e., if it had infinite resistance). Repeat the calculation usingthe real internal resistance you measured in step 2. Show your work in your lab book and

display your results in a table such as shown here:

R() Videal Vreal

1 k

100 k

10 M

Briefly discuss the significance of these results.

Report:

Your Laboratory Teaching Assistant will inform you when a report is due, and on which

experiment you will report. Make sure that you have recorded all necessary information and datain your laboratory notebook to enable you to prepare a report on this experiment, if so directed,

at some time in the future.

+

10V V R

100k

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Laboratory 3: DC Measurements


Laboratory 3

DC Measurements

Introduction:Voltage and current values may be used to determine the power consumed (or provided) by an

electrical circuit. Electric power consumption is a very important factor in all electricalapplications, ranging from portable computers to megawatt industrial complexes. Thus, an

understanding of power and how it is measured is vital to all engineers.

Objective:By the end of this lab, the student should know how to make DC measurements of voltages andcurrents to determine power dissipation/delivery for circuit elements, branches, and various

combinations of elements and branches.

Preparation:Read the introductory material in the ECE 202 textbook describing the passive sign convention

for circuit elements. Also, review the lab manual section Use of Laboratory Instruments. Priorto coming to lab class, calculate the values of voltage, current, and power absorbed/delivered

for each circuit element in Figure 3.1 (i.e. do Part 0 of the Procedure). Also, sketch in your labnotebook the circuit diagrams to be used in each part of the procedure and have a table prepared

for each part in order to record data.

Equipment Needed:NI-ELVIS workstation.Resistors as required.

Procedure:

0) For the circuit given in Figure 3.1, calculate the voltages across and currents through each

circuit element. Using these values, determine the power absorbed or delivered by each circuitelement. Include your calculations in your laboratory notebook. Record all of your theoretical

results in a table for later comparison with your experimental values.

Figure 3.1 - DC resistive network.

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1) Set up the circuit in Figure 3.1. Adjust the output of the DC power supply to 10V and verifywith the digital multimeter (DMM). Using the digital multimeter function in the NI-ELVIS

workstation (set to measure DC Volts), measure the voltage across each individual circuitelement. Before making each measurement, use the connection scheme shown in Figure 3.2 to

verify that your voltmeter connection method is correct. Record the measurements in your

laboratory notebook. For each measured voltage, determine the percent difference from thetheoretical value determined in Part 0.

Figure 3.2 - Connection scheme for circuit voltage measurements.

2) For the circuit in Figure 3.1, measure the current through each circuit element using the digital

multimeter function in the NI-ELVIS workstation (set to measure DC Amps). Before eachmeasurement, the circuit will have to be turned off and rewired to insert the ammeter in series

with the component under test. Before making each measurement, use the connection scheme

shown in Figure 3.3 to verify that your ammeter connection method is correct. Record themeasurements in your laboratory notebook. For each measured current, determine the percentdifference from the theoretical value determined in Part .

Figure 3.3 - Connection scheme for circuit current measurements.

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3) Using your measurements from Parts 1 and 2, calculate the power absorbed or delivered byeach circuit element. Record these values in your laboratory notebook. Compare them with

the values obtained through circuit analysis in Part 0. Calculate the percent difference fromthe theoretical values.

Probing Further:

1) What is the relationship between the power values obtained from your measured values of

voltage and current and those calculated theoretically in Part 0? What do you think are sourcesof error? Explain.

2) How does the sum of power absorbed by the resistances in the circuit compare to the amountdelivered by the source?

Report:




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Laboratory 4: Introduction to B2 Spice


Laboratory 4

Introduction to B2 Spice

Introduction:

The widespread availability of computers has enabled the development of software which quite

accurately models the behavior of electrical circuits. The most widely used program is SPICE,

developed by the University of California-Berkeley in the mid-1970's and updated several timessince then. Amongst the commercially available versions of SPICE is B2 Spice from Beige Bag

Software. B2 Spice is loaded on the ECE 211 laboratory computers, and a Lite version isavailable for free from the company (http://www.beigebag.com/adv4_lite.htm). As an

introduction, you will learn to use B2 Spice circuit simulation software with relatively simplecircuits. Later, in the introductory electronics courses ECE 320 and ECE 321, you will learn to

use B2 Spice to simulate the operation of more advanced components such as diodes, transistors,

and even a few integrated circuits.

Objective:

This lab should give the student a basic understanding of how to use B2 Spice to simulate circuit

operating conditions. After this lab, the student should be able to use B2 Spice to solve or checkbasic circuit problems.

Preparation:

Prior to coming to lab class, calculate the voltages and currents for each resistor shown in the

circuit of Figure 4.1 (i.e. do Part 0 of the Procedure).

Equipment Needed:

A computer with B2 Spice loaded and ready to use.
http://www.beigebag.com/adv4_lite.htmhttp://www.beigebag.com/adv4_lite.htm

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Procedure:

0) Before coming to lab, determine the voltages across and currents through each resistor in the

circuit of Figure 4.1.

Figure 4.1 - Resistive network for hand analysis and B2 Spice simulation.

1) In the lab, your LTA will go through the guidelines for using computer equipment in aCollege of Engineering & Science laboratory. Then the LTA will provide an introduction to

the B2 Spice software environment. During this instruction session, you will learn how to:

a) Open the software and create a new project.

b) Place circuit components in your project workspace.

c) Connect circuit components together.

d) Set up circuit measurements.

e) Change simulation execution settings.

f) Run simulations.

g) Display or export the simulation output.

One important principal to keep in mind is that if you want B2 Spice to display a graph or a

table of something, you must include a suitable measurement device (e.g., voltmeter or

ammeter) for that value. Anything without a meter wont be graphed.

2) Use B2 Spice to solve for all of the resistor voltages and currents for the circuit of Figure 4.1.

Your problem solutions, using B2 Spice, are to be turned in. Compare your simulationmeasurements with the results of your calculations in Part 0.

3) Use B2 Spice to simulate the circuit used in Laboratory 3 (Figure 3.1). Determine the voltagesand currents for each circuit component. Your problem solutions, using B2 Spice, are to be

turned in.

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4. Variability is inherent in any process, including the manufacture of resistors and capacitors.Such components are usually marked with a nominal (target) value and a tolerance within

which the actual value might fall.

10V

V1

1000R1

510

R2

510

R3

Figure 4.2: B2 Spice representation of the circuit of Figure 3.1

Consider the circuit of Figure 4.2 the same circuit you simulated in Procedure 3 andmeasured in Laboratory 3. If the resistors you used in Laboratory 3 had a tolerance of 10%,their actual values might have been anywhere in the following ranges:

900 R1 1100459 R2 561

459 R3 561

To understand how such variation might affect your measurements of current and voltage in

an actual circuit, use B2 Spice to calculate the currents and voltages if the resistors were atsome of their extreme values, as indicated in the table below:

R1 R2 R3 I1 I2 I3 V1 V2

1100 459 561

900 459 561

1100 459 459

900 459 459

(I1, I2, and I3 are the currents through R1, R2, and R3. V1 is the voltage across R1 and V2 isthe voltage across R2 and R3.)

Compare the voltages and currents of the last row (900, 459, and 459) to the voltages

and currents found in the simulation of Procedure 3 and explain your observations.

For an understanding how the variability of a process is characterized by measurement of themean, the variance, and the standard deviation of a parameter, read Appendix C,

Fundamentals of Statistical Analysisin this manual.

Probing Further:

1) How do the B2 Spice simulation results in Part 1 compare to your calculations in Part 0? Can

you account for any differences?

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2) How do the B2 Spice simulation results of Procedure 3 compare to your measurements inLaboratory 3? Can you account for any differences?

Report:

The problem solutions are due the next period. Include a title page and a brief procedure for each

circuit. Report the results from B2 Spice, and highlight these results on the printouts. Include acircuit diagram with each problem. Problem statements, files, and printouts should be included at

the end of the report.

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Laboratory 5: Network Theorems I


Laboratory 5

Network Theorems I

Introduction:An understanding of the basic laws of electrical voltages and currents is essential to electricalengineering. Circuit analysis is dependent upon knowing the nature of the laws governing

voltage and current characteristics. This lab studies Kirchhoff's Voltage Law, Kirchhoff's CurrentLaw, voltage division, current division, and equivalent resistance.

Objective:By the end of this lab, the student should understand KVL, KCL, voltage division, current

division, and equivalent resistance combinations.

Preparation:

Read the material in the textbook that describes Kirchhoff's Voltage Law, Kirchhoff's CurrentLaw, voltage division, current division, and equivalent resistance combinations. Be able toperform circuit calculations using these principles. Before coming to class, analyze each circuit

and determine the theoretical values that should be obtained during the lab. Verify yourcalculations by performing B2 Spice simulations for each circuit. Record both your calculations

and simulation results in your laboratory notebook.

Equipment Needed:NI-ELVIS workstation.Individual resistors as required.

Resistance substitution box.

Procedure:

1) Adjust the output of the DC power supply to 10V and verify with the digital multimeter. Set

up the circuit as shown in Figure 6.1. Measure and record the total current into the circuit.

Using the measured current and voltage, determine the equivalent resistance of the parallelcomponents in the circuit. Replace the resistors with a resistance substitution box set to the

equivalent resistance and measure the current as before. Compare the experimentallydetermined equivalent resistance to the theoretical value.

Figure 6.1 - Determining parallel equivalent resistance.

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2) Adjust the output of the DC power supply to 10V and verify with the digital multimeter. Setup the voltage division circuit as shown in Figure 6.2. Begin with R = 510 and measure the

voltage across each resistor. Repeat with R = 1 k, 2 k, 3 k, 4.3 k, and 5.1 k. Comparethe measured voltages to those calculated using the voltage divider relation.

Figure 6.2 - Effect of R on the component voltages.

3) Adjust the output of the DC power supply to 10V and verify with the digital multimeter. Set

up the current division circuit as shown in Figure 6.3. Begin with R2 = 510 and measure thecurrents I1, I2, and I3. Repeat with R2 = 1 k, 2 k, 3 k, 4.3 k, and 5.1 k. Compare the

measured currents to those calculated using equivalent circuit resistance and the currentdivider relation. Determine whether or not each set of measurements agrees with Kirchhoff's

Current Law.

Figure 6.3 - Sum of currents at a node.

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4) Adjust the output of the DC power supply to 10V and verify with the digital multimeter. Setup the circuit as shown in Figure 6.4. Measure the voltage across each component. Compare

the measured voltages to those calculated using the voltage divider relation. Determinewhether or not your measurements agree with Kirchhoff's Voltage Law.

Figure 6.4 - Sum of voltages around a loop.

5) Adjust the output of the DC power supply to 10V and verify with the digital multimeter.

Set up the circuit as shown in Figure 6.5. Measure the voltage across each component inloop 1. Repeat for loop 2 and loop 3. Compare your measured values with the terms in the

KVL equation written for each loop. Determine whether or not your measurements agreewith Kirchhoff's Voltage Law. Explain the reasons for any discrepancies found.

Figure 6.5 - Sum of voltages around different loops.

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Probing Further:

1) In part 2, what would the value of R have to be so that the voltage across R is 4/5 of the source

voltage? Your answer should be quantitative (i.e. a number).

2) In part 3, what would the value of R2

have to be so that the current through R2

is 10 times the

current through R3? Your answer should be quantitative.

Report:

Your Laboratory Teaching Assistant will inform you when a report is due and on which

experiment you will report. Make sure that you have recorded all necessary information and data

in your laboratory notebook to enable you to prepare a report on this experiment, if so directed,at some time in the future.

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Laboratory 6: Network Theorems II


Laboratory 6

Network Theorems II

Introduction:This lab focuses on the Thvenin equivalent and maximum power transfer theorems. Complex

circuits are often replaced with their Thvenin equivalent to simplify analysis. For example, inthe analysis of large industrial power systems the Thvenin equivalent is used in short circuit

studies. Maximum power transfer is also an important concept which allows the designer todetermine an optimal design when power is a constraint.

Objective:

By the end of this lab, the student should be able to verify Thvenin's equivalence theorem andthe concept of maximum power transfer.

Preparation:Read the material in the textbook that describes Thvenin's equivalence theorem and maximum

power transfer.

Equipment Needed:

NI-ELVIS workstation.

Individual resistors as required.Resistance substitution box.

Procedure:

1) This part of the lab illustrates the use of Thvenin's theorem. Adjust the output of the DCpower supply to 10V and verify with the digital multimeter. Set up the circuit as shown inFigure 7.1. Measure the open circuit voltage between nodes A and B. Measure the short

circuit current between nodes A and B (i.e. connect the ammeter between nodes A and B).Using these measurements, determine the Thvenin equivalent circuit. Set up the newly

determined Thvenin equivalent circuit and verify that this circuit has the same open circuitvoltage and short circuit current as the previous circuit. Save this circuit for Part 2.

Figure 7.1 - Determining the Thvenin equivalent circuit.

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Laboratory 6: Network Theorems II


2) This part of the lab is to illustrate maximum power transfer. Use the Thvenin equivalentcircuit developed in Part 1. For a resistance substitution box R between nodes A and B,

measure the current through and voltage across R if R = 0. Repeat for R = 100, 120,..., 500 (in 20 increments). Determine the power dissipated by the resistor for each

value of R. Plot power vs. resistance. At which value is the power a maximum?

Probing Further:

1) Use B2 Spice to determine the Thvenin equivalent for the circuit in Part 1. First, enter the

circuit shown in Figure 7.1 using node B as the reference or "ground" node. The voltage at

node A is then the open circuit voltage. To measure the short-circuit current between pointsA and B, place an ammeter between the points. Determine the Thvenin equivalent and

compare to your experimentally obtained equivalent circuit in Part 1. Record your B2 Spiceprograms and the data obtained from the simulation in your laboratory notebook by pasting

in the printouts. Highlight the open-circuit voltage value and short-circuit current valueobtained from the simulation.

2) Use B2 Spice to simulate the circuit of Part 2. Start with the value of R = Rmax_pwrthat youdetermined experimentally to give maximum power transfer and find, from the B2 Spice

simulation, the power delivered to this resistance. Then repeat with 20 incrementsthrough 100 (i.e. for Rmax_pwr 100 < R < Rmax_pwr+ 100). Compare the values of

power obtained by simulation with those you obtained experimentally. Record your B2Spice programs and the data obtained from them in your laboratory notebook.

Report:




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Laboratory 7: The Oscilloscope


Laboratory 7

The Oscilloscope

Introduction:The digital oscilloscope allows the engineer to examine time varying waveforms in order to

determine the magnitude, frequency, phase angle, and other waveform characteristics whichdepend upon the interaction of circuit elements with the sources driving them.

Objective:

By the end of the lab the student should be familiar with the controls of a digital oscilloscope andbe able to use the instrument to observe periodic waveforms.

Preparation:

Review 'XYZs of Oscilloscopes', available at: www.tek.com (60+ pages). Be familiar with the

following: voltage scaling (Volts/division), time base (seconds/division), input coupling,triggering, and measurement probes.

Equipment Needed:

NI-ELVIS workstation.Individual resistors as required.

Procedure:

0) At the beginning of class, your LTA will review the virtual oscilloscope software used with

the NI-ELVIS workstation.

1) Basic setup. Connect a cable with BNC fitting to the BNC jack for CH 0 of the oscilloscopeon the left side of the NI-ELVIS II. Connect the cables red lead to the FGEN output; connect

the cables black lead to GROUND. (Important note: Internally the oscilloscopes ground isconnected to the NI-ELVIS circuit ground, therefore, the oscilloscope can only measure

voltages across components that are connected to ground. Avoid grounding errors!)

Set the function generator to output a 100Hz sine wave with amplitude = 3.0 VPP and DC

offset = 0V. Open the oscilloscope window in the NI-ELVIS software. ENABLE the displayfor Channel 0. RUN the function generator and the oscilloscope. Turn on the measurement

function for Channel 0 and record the measured values for RMS voltage, peak-to-peak

voltage, and waveform frequency. Sketch the displayed waveform in your laboratorynotebook. Compare your measurements with the expected values based on the functiongenerator output.

2)Source control. Connect CH 0 to SYNC (adjacent to FGEN). Sketch this waveform in yourlaboratory notebook. Reconnect CH 0 to FGEN. Change the function generator output to a

square wave, record the displayed waveform in your laboratory notebook, and measure thepeak-to peak output voltage. Repeat this measurement for a triangular wave.

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3) Voltage scaling. Reset the function generator to output a sine wave. Vary the vertical scalecontrol for Channel 0 using either the control knob or pull-down menu. Record the effect that

this control has on the displayed waveform. Set the control to 500mV/div and measure thepeak-to-peak magnitude of the displayed waveform by counting (estimate) the number of

peak-to-peak divisions and multiplying by the vertical scale. Compare this result with the

measurement given by the oscilloscope.

4) Voltage offset manipulation. Vary the vertical position control in the oscilloscope and recordthe effects in your laboratory notebook, noting any changes in the measured RMS voltage.

Return the offset to zero and add a DC offset of 0.5V to the function generator output. Recordthe effects in your laboratory notebook, noting any changes in the measured RMS voltage.

5)Time scaling. Return the DC offset in the function generator to 0V. Using either the timebasedial or pulldown menu, adjust the timebase of the oscilloscope display to the fastest setting

(5S/div). Record the effect that this setting has on the displayed measurements for thewaveform. Gradually increase the timebase through each available setting until the slowest

setting has been reached (200mS/div). Record the effect that this control has on themeasurement of voltage and frequency. Return the timebase to a setting where 1-3 full cycles

of the output sine wave is viewable. Set the Acquisition Mode to RUNONCE and press RUNto capture a single sweep of the output waveform and measure the period of the waveform by

counting (estimate) the number of time divisions for a single cycle and multiplying by thetime scale. Compare this measurement to the inverse of the frequency measured by the

oscilloscope.

6) Triggering / synch function. Return the screen update to 'RUN'. Adjust the triggering pull-

down menu t 'Edge' and record the oscilloscope response. Vary the function generator peakamplitude to verify that the oscilloscope is continuing to update the display in this mode of

operation.

7) Cursor function. Set the function generator to output a 100Hz sine wave with peak

amplitude = 3.0 VPP and DC offset = 0V. Return the triggering function to 'Immediate'.Display a single screen update of between 1-3 cycles of the output function. Switch the

cursors function on and drag the cursors to appropriate points on the waveform to measure theperiod of the sine wave. Then adjust the cursors to measure the peak-to-peak voltage of the

sine wave. Compare these measurements to those expected based on the function generator'soutput settings.

8) Connect the voltage divider circuit shown in Figure 8.1. Set the function generator to output a1kHz sine wave with amplitude = 2VPP and DC offset = 0. Display the function generator

output on Channel 0 of the oscilloscope and the voltage across the 100 resistor onChannel 1. Be careful to avoid grounding errors. Display and measure these voltages simul-

taneously. Measure the period of both waveforms using the cursor function. Sketch thewaveforms in your laboratory notebook and record your settings for Volts/div and

seconds/div. Compare your voltage measurements with theoretical calculations based on thevoltage divider equation. Compare your waveform period measurement with the theoretical

value obtained from the input frequency.

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Figure 8-1. Voltage divider circuit used in Parts 8 and 9.

9) Reverse the polarity for the output voltage measurement on Channel 1. Repeat your voltageand period measurements as in Part 8, sketch the resulting waveforms in your laboratory

notebook, and record your settings for Volts/div and seconds/div.

Probing Further:

1) What purpose does the FGENs SYNC serve?

2) Why does the RMS voltage measurement vary when an offset is added in the functiongenerator but not when changed in the oscilloscope?

3) In Part 9, what effect did reversing the polarity of the output voltage measurement have on theoscilloscope display and the oscilloscope voltage measurements?

4) How is the accuracy of your measurements affected by adjustment of the volts/divisioncontrol? Seconds/division control?

5) How would the peak-to-peak and RMS voltage measurements be affected by the presence ofnoise in a displayed waveform? Would this be a clear representation of the actual signals in a

circuit? What steps would you take to determine if noise is an issue in your oscilloscopemeasurements and how would you mitigate it, if necessary?

Report:

Your Laboratory Teaching Assistant will inform you when a report is due, and on whichexperiment you will report. Make sure that you have recorded all necessary information and data


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Laboratory 8: RC and RL Circuits


Laboratory 8

RC and RL Circuits

Introduction:This lab deals with RC and RL circuits. RC and RL circuits are used in many configurations for

a large variety of design purposes. In addition, real components can be modeled in a givenfrequency range by a combination of R and C or R and L, as appropriate. For example, a

wirewound resistor can be modeled as a "pure" resistor, R, at DC or very low frequencies, but asthe frequency of operation increases, the inductive effects of the winding must be taken into

account. This lab illustrates some of the basic features of the transient response of circuits inwhich resistance and capacitance or resistance and inductance are both present.

Objective:

By the end of this lab, the student should know how to measure the time constants of RC and RL

circuits.

Preparation:

Review the material in the textbook on RC and RL circuits.Before coming to the lab, determine

the theoretical time constants of the circuits used in the lab. Be sure to account for the 150output impedance of the function generator in your calculations.

Equipment Needed:

NI-ELVIS workstation.Resistance substitution box

Capacitance substitution boxInductance substitution box

Procedure:

1) Set up the RC circuit shown in Figure 9.1. Set the function generator to give a square wave

output with magnitude equal to 500mV. Measure both the source voltage and the voltage

across the capacitor with the digital oscilloscope. (Avoid grounding errors!) Adjust thefrequency of the function generator so that the waveform shown has definite flat sections at

the top and bottom. Using the oscilloscope cursors function, determine when the voltagereaches 0.632 times its final value. Sketch the waveform for a complete cycle in your

notebook, recording the voltage scale and time scale values. Clearly label the sketched

waveforms, including initial and final values. Repeat these steps using C = 0.047 F andC = 0.1 F. For each circuit the frequency of the waveform generator may have to be changedto achieve the flat sections at top and bottom of the waveforms.

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Figure 9.1 - RC circuit.

2) Now modify the circuit of Figure 9.1 by swapping the positions of the resistor and capacitor.

Repeat the measurements in Part 1 using C = 0.01F, 0.047F, and 0.1F while observing thevoltage across the resistor. Find the time when the voltage reaches 0.368 times its initial value

(the voltage decays here). Compare your measured values of the RC circuit time constant in

Parts 1 and 2 with the theoretical values.

3) Set up the RL circuit shown in Figure 9.2. The function generator should be set up as in Part1. Use an inductance substitution box for the inductor. Measure both the source voltage and

the voltage across the resistor with the digital oscilloscope. Adjust the frequency of thefunction generator so that the waveform has definite flat sections at the top and bottom. Using

the oscilloscope cursors function, determine when the voltage reaches 0.632 times its finalvalue. Sketch the waveforms for a complete cycle in your notebook, recording the voltage

scale and time scale values. Clearly label the sketched waveform, including initial and finalvalues. Repeat these steps using L = 400m, 600m, and 800mH. For each circuit the

frequency of the function generator may have to be changed.

Figure 9.2 - RL circuit.

4) Now modify the circuit of Figure 9.2 by swapping the positions of the resistor and inductor.Repeat the measurements in Part 3 using L = 200m, 400m, 600mH, and 800m while

observing the voltage across the inductor. Find the time when the voltage reaches 0.368 timesits initial value (the voltage decays here). Compare your measured values of the RL circuit

time constant in Parts 3 and 4 with the theoretical values.

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Probing Further:

1) Use B2 Spice to simulate the RC circuit response for the circuit of Figure 9.1. Repeat for the

RL circuit response for the circuit of Figure 9.2. For both, use B2 Spices Transient Sweepsimulation to obtain waveforms and compare these waveforms to those you sketched from

your experiments.

2) Explain the significance of the 0.632 and 0.368 multipliers and why they are used in the lab.

Report:

Your LTA will inform you when a lab report is due.

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Laboratory 9: Series RLC Circuits


Laboratory 9

Series RLC Circuits

Introduction:This lab illustrates some of the properties of RLC circuits. The circuit response is given by

2

1 2 2

1,

2 4

R Rs s

L L LC ,

where s1and s2are the poles of the characteristic equation.

Define2

R

L and 0

1

LC .

Depending on the component values, series RLC circuits are overdamped, critically damped, orunderdamped. The conditions for the three cases are as follows:

Overdamped: 2 20

Critically damped: 2 20

Underdamped: 2 20

For the component values used in this experiment, 2 20 , so the circuit is underdamped. Thus,

the roots of the characteristic equation are complex. If we define

22 2

0 2

1 2

4d

R

LC L T

where T = period,

then the circuits current may be written

( ) ( cos sin )t d di t e A t B t

.

Objective:

By the end of this lab, the student should be able to relate the nature of the physical response of a

series RLC circuit to the parameter values and ddetermined by the component values.

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Preparation:

Review the material in the textbook on the RLC circuit response. Review the concepts ofoverdamped, underdamped, and critically damped response. Before coming to the lab, calculate

the theoretical parameter values ofs1, s2, , d,andTfor the circuit used in the lab (i.e., do Part 0of the Procedure).

Equipment Needed:

NI-ELVIS workstationResistance substitution box

Capacitance substitution boxInductance substitution box

Procedure:

0) Calculate the values ofs1, s2, , d,and Tfor the circuit shown in Figure 10.1.

Figure 10.1 Series RLC circuit

1) In Figure 10.1 Rtotis the total resistance of the circuit. In practice, part of that resistance is due

to the internal resistance of the function generator and part is supplied by the resistancesubstitution box.

Rtot= RFGEN+ RS

where RFGENis the internal resistance of the function generator, and RSis the resistance set on

the resistance substitution box.

Set up the circuit as shown in Figure 10.2. Before connecting them, verify the values of L and

C using the NI-ELVISs DMM. Since the function generator has internal resistance RFGEN inthe range of 50 to 150, set the resistance substitution box to RS= 100. Set the function

generator to output a square wave with amplitude = 2V PP, DC offset = 0V, and frequency inthe range of 10Hz to 100Hz.

L = 100 m

Rtot = 250

C = 0.01F

Function Generator

VFGEN =2 VPP

Square wave

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Figure 10.2 Series RLC circuit to measure voltage on inductor

a) Connect CH 0 of the oscilloscope to display the voltage across the inductor. To avoid a

grounding error, the inductor must have one lead connected to ground.

b) To get a stable image of the circuit oscillations, connect a lead from the FGEN output toCH1 of the oscilloscope. Then set the scopes trigger to EDGE, CH 1, rising slope.

c) Adjust the period of the square wave, if necessary, so that the damped sinusoidal waveform

decreases to a negligible value (i.e., dampens out) before the next square-wave pulse

occurs. Something in the range of 10 Hz to 100 Hz probably will be adequate.

d) Draw an accurate representation of the transient sinusoidal waveform (the damped

oscillations) in your laboratory notebook. If you have a USB flash drive, you can use the

oscilloscopes LOG button to download a log file of the waveform data for later analysis ina spreadsheet. To do so, you must first stop the acquisition by pressing STOPor by using the

RUNONCE mode.

2) Expand the time scale of the oscilloscope to show 3 to 6 peaks of the damped sinusoidal

oscillation. Using the CURSORS function of the oscilloscope, measure the period of thedamped sinusoidal waveform. Compare this value to Tobtained in Part 0.

3) Measure the peak height of the first full peak of the damped sinusoidal waveform and the peakheight at the next peak (+1 cycle). Measure the time difference t between these two peaks.

a) Determine the Neper frequency (damping coefficient), , using your measurements and the

equation

2 1t

peak peakV V e .

b) Compare your measured to the value you calculated in Part 0.

c) For your experimental , calculate the total resistance Rtotin the circuit. ( = Rtot/2L)

d) Calculate the function generators internal resistance RFGEN= Rtot RS.

4) Now knowing RFGEN, adjust RS so that Rtot= 250 . Again measure the damping coefficient,, and compare the new measured value to your calculated value from Part 0.

L = 100 mH

RS = 100

C = 0.01F

RFGEN

Function Generator

VFGEN =2 VPP

Square wave

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5) Swap the positions of the inductor and the capacitor, as shown in Figure 10.3.

Figure 10.3 Series RLC circuit to measure voltage on capacitor

Connect CH0 of the oscilloscope to measure the voltage across the capacitor, being careful to

avoid grounding errors. Continue to trigger the scope using the FGEN signal on CH1, asbefore. In your laboratory notebook, sketch the waveform of the voltage across the capacitor.

Notice that if you were to perform the calculation for using these data, you would need tosubtract from the peak heights the 1-volt offset provided by the pulse from the function

generator. Doing so, you could again calculate as in Part 3.

Critical damping: For the values of L and C used in this circuit, calculate the value of total

series resistance Rtot that gives critical damping. Change the resistance RS so that Rtotequalsthis value. Again observe the voltage drop across the capacitor and sketch the resulting

waveform in your laboratory notebook.

Overdamped: Change RS so that Rtot is 10 times the value you calculated for critical

damping. Observe and record the capacitor voltage response.

Probing Further:

1) Describe the differences between the underdamped, overdamped, and critically damped

responses in the capacitor voltage, VC. What are the potential advantages or disadvantages of

an electrical system behaving in each mode of operation? What is the functional form of thetransient response (be specific) if the circuit is critically damped?

2) Explain why the inductor voltage, VL, is greater than the amplitude of the incoming square

wave at the time of a square wave transition (initial condition).

Report:




VFGEN =2 VPP

Square wave

L = 100 mH

RS = 100

C = 0.01F

RFGEN

Function Generator

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Laboratory 10: Statistical Analysis


Laboratory 10

Statistical Analysis

Introduction:The student is already aware of some error introduced by assuming ideal meters in the

measurement process. Another uncertainty lies in the use of the circuit components themselves.While a component is designed to have a particular value (its "nominal" value), which is marked

on the outside covering (the "case" or "encapsulation"), random fluctuations in materials andproduction processes will result in some range of values for the manufactured devices. Thus,

components are usually specified by a nominal value and a range, called the tolerance, in whichthe actual value is expected to lie. For example, resistors are specified as being within a stated

tolerance of the given (nominal) value. This tolerance can be as small as 1% for "precision"resistors to as large as 20%. The tolerance may be indicated by a color band or by a percentage

value printed on the body of the resistor. It is important to know how to identify the tolerance of

the resistors used in a particular circuit and to understand what the specified nominal value andtolerance for a component means statistically.

Objective:

By the end of this lab, the student should know how to apply statistical methods to obtain the

best estimate of the true value of a circuit component.

Preparation:

Read Appendix C, Fundamentals of Statistical Analysis. Become familiar with the concepts ofmean, standard deviation, and variance and the formulas used for calculating these quantities.

Equipment Needed:NI-ELVIS II workstation.

Procedure:

0) The lab instructor will provide each team with a group of five resistors. Each group of

resistors should be labeled GROUP A, GROUP B, GROUP C, etc. These will be passed inturn from lab team to lab team.

1) For each group of resistors, measure the resistance of each component using the NI-ELVISdigital multimeter. Make a table for each group, recording the resistances.

2) For the resistors in each group, calculate the mean, the standard deviation, and the variance.Make a table showing these values for each of the groups. When you make this table, include

a row, labeled "TOTAL", and calculate the mean, standard deviation, and variance for all ofthe resistance values that you measured.

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Laboratory 10: Statistical Analysis


3) Make another table with rows labeled "TEAM 1", "TEAM 2", etc. and record the values ofmean, standard deviation, and variance for each resistor group and for the total determined by

other lab teams in Part 2. Why do the values differ?

4) Using the information in Parts 2 and 3, what would be the best estimate of the resistance of

each group? What would be the best estimate of the resistance for all groups of resistorscombined? Why?

Probing Further:

1) Is it reasonable to assume the resistors have a normal distribution? Why?

2) How does the mean value of resistance for the total, obtained by your lab team, compare to thenominal value of resistance marked on the resistors body?

3) How does the standard deviation obtained by your team compare to the tolerance marked onthe resistor case?

Report:



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Laboratory 11: Design Lab


Laboratory 11

Design Lab

Introduction:In this lab you will design and build a circuit to meet certain criteria. In calling for a circuit

design, two fundamental questions must be answered: 1) "What function is the circuit toperform?", and 2) "How well is the circuit expected to perform this function?". The detailed

answers to these questions are usually called the functional requirementand the specifications,respectively.

Objective:

The objective of this laboratory exercise is to introduce you to the nature of the engineeringdesign process, i.e., the process of selecting combinations of components to perform a given

function with a given degree of precision.

Preparation:

Review the material in your circuits textbook on voltage dividers. Before you come to lab, youshould have your circuit design completed, with the design procedure and the resulting circuit

recorded in your laboratory notebook. This is not a team exercise. Each individual will berequired to have a design completed in the notebook prior to coming to lab class.

Equipment Needed:

? (you specify).

Procedure:

1) You are to design a voltage regulator circuit that will provide 7.00V across a load resistance,

RL, which may vary anywhere between 1000 and 1500. The supply voltage source is to be10.00V. You are to use resistors R1andR2between the 10V source and RLin a voltage divider

network. You must select the values of these resistors to obtain no more than a +5% variationabout 7.00V as the value ofRLranges from 1000 to 1500. Initially, you can assume that

the selected values of resistances R1 andR2 are precise (i.e. 0% tolerance). In your laboratorynotebook show your design procedure and your calculations to determine values ofR1and R2.

2) After discussing the circuit design with the lab instructor, connect the circuit and test it. Whenyou have met the specifications, demonstrate the performance of your regulator circuit to your

LTA.

3) Suppose that the specifications had included the additional requirement that the voltage

divider was to dissipate the minimum possible power while meeting the 7.00V 5%specification. How would this have changed your design?

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Laboratory 11: Design Lab


Probing Further:

1) What were the major considerations in making the design? Did the available components

affect your design? How would you design the circuit if only 10% tolerance resistors instandard sizes were available? What are the standard resistor values available for commercial

resistors with a 10% tolerance? IfR1 andR2 are the nominal (standard) values of the resistorsused in your voltage divider and the extreme values are:

R1H= 1.1R1 R1L= 0.9R1

R2H= 1.1R2 R2L= 0.9R2,

then what difference would various combinations make in the performance of your circuit?

2) Use B2 Spice to determine the effect on the output voltage across the load resistor of voltage

divider resistor values that vary up to 10% from the nominal values.

Report:



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Laboratory 12: Final Exam


Laboratory 12

Final Exam

Introduction:This has been your first engineering laboratory. Although you have been provided with a

"cookbook" (this manual), hopefully you have not just blindly followed instructions in order toget a good grade. If you have, you have cheated only yourself. The theory which you have

learned from your textbook and lectures is a way of looking at reality and thinking about how toorganize experience, i.e., dealing with real, physical things. It is only through combining

practical experience with theory that you can begin to develop the necessary analytical skills toaid you in "taking things apart and putting them together in new ways" that is the essence of the

practice of real engineering.

Objective:

This examination is designed to help you and your LTA determine how much you havedeveloped your knowledge, skills, and self confidence.

Preparation:

Review your lab manual. Think carefully of the procedures which you have followed and whatyou have learned from them. How do you measure voltage, current, resistance, frequency, etc.?

How accurate are your measurements? When your measurements do not agree with those of yourpeers, what is the cause? How do your measuring instruments affect the circuit in which you are

trying to make measurements?

Equipment Needed:

Pencil

Calculator

Procedure:

1) The final exam will consist of a written exam and a practical exam. The practical examinvolves performing a lab procedure to obtain a desired result. The written exam will cover the

application of theory to understand circuit behavior, based upon your laboratory experiences inthis course.

Probing Further:

1) This has been your first in a series of four (4) laboratory courses. What have you done todevelop your expertise and skills? What will you do differently in the next course? What have

you learned from your experience?

Report:

No report is due for this experiment. Laboratory notebooks are to be turned in to the LTA forevaluation.

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Part III

Appendices

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Appendix A: Safety


Appendix A:

Safety

Electricity, when improperly used, is very dangerous to people and to equipment. This isespecially true in an industrial environment where large amounts of power are used, and where

high voltages are present [A-1]; in environments where people are especially susceptible toelectric shock such as maintenance of a high voltage system (while in operation) or in hospitals

where electrical equipment is used to test or control physiological functions [-2, -3]; and in anexperimental or teaching laboratory where inexperienced personnel may use electrical equipment

in experimental or nonstandard configuration.

Engineers play a vital role in eliminating or alleviating the danger in all three types of

environments mentioned above. For conditions where standard equipment is used in standardconfigurations, governmental agencies and insurance underwriters impose strict laws and

regulations on the operation and use of electrical equipment including switchgear, power lines,safety devices, etc. As a result, corporations and other organizations in turn impose strict rules

and methods of operation on their employees and contractors. Engineers who are involved inusing electrical equipment, in supervising others who use it, and in designing such systems, havea great responsibility to learn safety rules and practices, to observe them, and to see that a safe

environment is maintained for those they supervise. In any working environment there is alwayspressure to "get the job done" and take short cuts. The engineer, as one who is capable of

recognizing hazardous conditions, is in a responsible position both as an engineer and as asupervisor or manager and must maintain conditions to protect personnel and avoid damage to

equipment.

Because of their non-standard activities, experimental laboratories are exempt from many of

these rules and regulations. This puts more responsibility on the engineer in this environment toknow and enforce the safest working procedures.

The knowledge and habit-forming experience to work safely around electrical equipment and theability to design safe electrical equipment begins with the first student laboratory experience and

continues through life. This includes learning the types of electrical injuries and damage, howthey can be prevented, the physiology of electrical injuries, and steps to take when accidents

occur.

Physiology of Electrical Injuries:

There are three main types of electrical injuries: electrical shock, electrical burns, and fallscaused by electrical shock. A fourth type, 'sunburned' eyes from looking at electric arcs, such as

arc-welding, is very painful and may cause loss of work time but is usually of a temporarynature. Other injuries may be indirectly caused by electrical accidents, e.g., burns from exploding

oil-immersed switch gear or transformers.

Although electric shock is normally associated with high-voltage AC contact, under some

circumstances death can occur from voltages from substantially less than the nominal 120 Volts

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Appendix A: Safety


AC found in residential systems. Electric shock is caused by an electric current passing through apart of the human body. The human body normally has a high resistance to electric currents so

that a high voltage is usually required to cause lethal currents. This resistance is almost all in theskin, but when the skin is wet its resistance ismuchlower. When a person is hot and sweaty or is

standing in water, contact with 120 Volts or less is likely to cause a fatal shock.

Electric shock is not a single phenomenon but is a disturbance of the nerves that is caused by

electric current. A current through a part of the body such as the arm or leg will cause pain andmuscle contraction. If a victim receives an electric shock from grasping a live conductor, a

current of greater than 15 to 30mA through the arm will cause muscle contractions so severe thatthe victim cannot let go. Similar currents through leg muscles may cause sudden contractions

causing the victim to jump or fall, resulting in possible injuries or death. It is also possible for aprolonged period of contact of more than a minute or so to cause chest muscles to be contracted,

preventing breathing and resulting in suffocation or brain damage from lack of oxygen.

The predominant cause of death by electric shock is generally attributed to ventricular

fibrillation, which is an uncontrolled twitching or beating of the heart that produces no pumpingaction and therefore no blood circulation. Unless c

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