AnnouncementsAnnouncements
A summary of each of the in-class lesson topics is being completed this semester. Reviewing this summary is particularly useful when preparing for quizzes. This document will be evolving throughout the semester, so you should check here for the latest version on a regular basis. Neither the topic list nor the format of this document have been finalized.
Class Schedule
The class schedule will be changed as the semester progresses, but the key dates -- quizzes, homework, projects -- will remain the same.
Note -- There is a small typo in the second problem. The standing wave pattern should be found on T1 for both cases. The posted version is correct. On 28 February, part of the class will be dedicated to an extra credit assignment. Most of the points in this assignment will be added to the Quiz 1 grade.
The assignment can be done with other students, but the TAs and instructors will not offer the usual help. They will clarify the language of the questions, but that is it. The assignment will be handed out and posted no later than Wednesday. The solutions must be handed in by the end of class on Thursday.
From time-to-time, we will recommend certain seminars that should be of interest
to you and also are understandable. (Most seminars at universities are intended
for grad students and faculty and, thus, are difficult for undergrads to
follow.) If you attend the seminars we recommend, you will earn extra credit
points if you email Prof. Connor a few comments on the presentation. For students who
cannot attend these seminars due to their class schedules, there will be other
opportunities for extra credit.
Office Hours/Open Shop
Office hours are posted by the names of each instructor or TA Project 2 - Extra Credit Activities
Project 2 -Beakman's Motor Speed Measurements
Comments on the Grading of Project 1 -- Most people did a reasonable job. Most of the channel blockers tested well. The double stub blocker worked very well. The following had a significant impact on the grade. (1) Were all parts included? For example, did the modeling include loss or was the task breakdown included? (2) Was the analysis approach discussed? What does the analysis suggest is to be expected when the experiments are done? How was it done? Where did the cable parameters used come from? Were the correct parameters used? (Here many people used parameters that were valid for DC conditions, but not high frequencies.) Why do you believe the analysis? (Most people had some paper and pencil analysis that was consistent with the PSpice or Matlab results. However, few commented on this.) (3) Were the results discussed? Is there agreement with the predictions of the modeling? If not, why? What information is contained in the plots? It is not enough to just staple the plots together. One must explain what the plots tell us. (Very few groups did this well.) (4) Why was the preferred design selected? Most people had a simple reason for the selection, but did not use all the information available in the plots. (5) The description of the experimental results should show that the design does work as expected. Thus, there should be a discussion of the relationship between the predicted results from the modeling and the measured response. (The only thing noted by most people was that the correct frequency was blocked and that the other frequency was passed. However, there were usually some quantitative differences between the model predictions and the experiments that were not discussed.
Project 1 -- There were a few typos in the write up. These have been fixed. Also, the language for the graded tasks has been modified to clarify a few points. Finally, there is a small problem with the cables we will be providing in the classroom for the experiment. The velocity of propagation is not the same as for the standard cables we have used until now. Please check the write up. (19 February 2002)
Project 1 Report -- Some suggestions on report writing. First, be sure that you are complete but do not include anything that is not necessary. For example, to describe your designs, you only need to draw a detailed circuit diagram and label it with enough information to do the analysis. A paragraph is probably all the text that you need to provide. Again, though, if you need some info to do the analysis (the properties of the voltage source or the transmission line, for example), you must include this in your design description. In the analysis section, your job is to explain how the analysis is done, to set it up, to motivate it with some simple paper and pencil analysis, etc. You essentially do all of the analysis without providing the output plots. In the next section, you present your output plots and discuss them. The question to ask yourself is what information is found in the plots? For example, your plot should show the range of frequencies that are passed without significant change or will be largely blocked. Again, the results of the analysis should allow you to select the preferred design and explain why. Finally, the experiment you do needs to be documented. Provide enough information to demonstrate that your design does indeed work as expected. (20 February 2002)
Project 1 -- Those of you who have taken or are taking Digital Electronics should have a copy of B2Spice. Most of you have figured out that you can simulate transmission lines with this version of spice too. If you have this program, you don't have to download the student version of PSpice. (21 February 2002)
Homework 6: Sorry for the delay in getting this assignment out. Note that the 4th problem is really quite simple. It contains a lot of background information that you can treat as cultural education unless you want to do the extra credit question. Then you will need some of the additional info provided. Homework 3: There are some small typos in the printed version handed out. These have been corrected in the pdf version posted on the Handouts webpage. (13 February 2002) Also, in problem 4, the surface charge IS inside the volume charge. While this is not normal, something like this is indeed possible. Make sure you understand the geometry of the problem. It is always a good idea to sketch the geometry before attempting the solution. (14 February 2002)
Homework 2: The last part of this problem involves a lossy line with some parameters given. These should be resistance and conductance, not resistance and admittance.
Homework 1 (continued): Since this is the first homework in a semester where we have changed the topic order for the course, here are some additional hints, comments and suggestions. The textbook covers the material of this assignment reasonably well. Please be sure to read all of the suggested readings. Also, try the CD that comes with your text. The CD includes the answers to some problems and some active examples that you can use to check your knowledge. One important comment about the text, the CD and what we do in class. It is possible to choose either the input end or the output end of a transmission line as z=0. We do both, depending on the problem. However, the textbook and CD seem to only use the output end as z=0. There are advantages and disadvantages to both choices (that is why both are used). You just have to remember which to check to see where the z=0 reference is. For example, in module 2.3a on the CD, the amplitude of the positive traveling wave has a phase of -144 degrees, since the reference is at the output end. If the reference had been at the input end,
the phase would have been zero. (Note -- Since the CD runs through a browser and the author only tested it using Internet Explorer, please let me know if there are any problems with other browsers. We have tried it with Netscape 6.2 with no problems so far. However, all parts of the CD have not been tested.) (21 January 2002).
Homework 1: There are two parts to this homework posted on the handouts page. No hard copy was handed out in class since the ECSE copying machine was down. We plan to have hardcopies available by Monday or Tuesday. Two versions of problem 3 were posted. Please be sure that you have the second version. It has only 2 parts and one is solved for you to show the method. (19 January 2002)
Suggested readings from the textbook and classnotes are listed on each lesson sheet. Be sure that you purchase the notes as soon as possible. The MathCAD Explorer and the Visual Electromagnetics Workbook we use in class can be downloaded from the web. Please see the bottom of the main Class Information Page under TEXT. There is an excellent set of computer tests addressing much of what we study in this class available from the Precision Teaching - Electromagnetics program at Georgia Tech. It is a good idea to download all of the units (either revision is fine) and test yourself when we have completed the subject covered. To test things out, try Unit 5 on circuits. All Fields and Waves I students should be able to do well with these questions from day one. Preparation/Homework assignments are posted on the Handouts page. Both the prep assignments for each class and the corresponding homework assigment are included. PDF versions of most course handouts will be available on the handouts page. (Accessible from home page ). You can also access many of them from the course schedule page.
Quiz Grade Distributions Will Be Posted Here. Also, pdf files with Course Grades and Prep Grades to this point are also posted. The grades are posted by alias. To figure out your alias, look for your quiz 1 grade and homework grades. If you cannot figure it out, stop by JEC 6003 and ask Audrey Hayner what your alias is.
For Quiz 1, add your extra credit (labeled q1-x in the posted spreadsheet) to your quiz grade. For quiz 2, add 10 to your quiz grade (this has already been done on the spreadsheet). For both grade totals, the following grade distribution holds: A: 88 and above, B: 75-87, C: 60-74, D: 50-59. For quiz 3, also add 10 points to your grade and then use the same distribution.
Please note that the grading system has been modified so that prep assignments now count 100 points, with only the best 20 counted. There were more than 20 such assignments, so that should allow anyone to miss one or two without a penalty.
All quizzes will be held in class on Wednesday evenings from 7-9 pm in DCC 318. There will be three quizzes during the semester on the following Wednesdays: 6 February, 20 March, 17 April. The Final Exam in not yet scheduled.
Extra Credit
Comments on Projects
Note that there are two extra credit activities listed at the end
of the project description. One is for people who like to build
things. The other is for those who are more theoretically inclined.
You may do either of them, but not both. Note that since these are extra, points
will NOT be awarded liberally. For the launcher, the points come
entirely from tested performance. If the launcher does not work,
there will be no second chance. For the motor model, the reports
must be clear, easy to read and focussed on the topic since there
is not much time available to read them. Finally, be careful with
the launcher since it involves high voltages and flying objects.
Please note that the measurement technique we use is not perfect. Thus, please take care in doing it and, should you find that your speeds are in excess of 60Hz, you will have
to get them confirmed by both a TA and an instructor (Braunstein, Michael or Connor).
1. Connect one channel of the 'scope across the battery. When the coil is not making contact with the battery, you should observe the battery voltage of a little more than 1.5 volts.
2. Set up the 'scope to measure a speed in the range you think your coil will turn (usually 10-100Hz). Most first-try motors turn nearer 10Hz than 100Hz. At 100Hz, you can hear the motor hum. Use the frequency measuring feature of the 'scope.
3. Start the motor. When the coil is connected, the voltage should drop because the impedance of the coil is much smaller than the impedance of the battery (part of your task is to confirm this). You should observe a series of square pulses and the coil connects
periodically to the battery, once each revolution. Set the time cursors to the beginning or
end of two consecutive pulses to get the frequency. For better accuracy, set the cursors to the beginnings of every 10th pulse and then multiply the frequency obtained by 10. This must be done for any really fast speeds. Note that it is possible for the coil to connect to the battery more than once per cycle if it is bouncing too much. Make sure that the paperclip cradle used to hold the coil does not close around the coil axis to avoid this problem. Also, the use of a non-conducting spring (possibly made with an insulated wire) will keep the coil from bouncing. This will make the coil go faster and make the measurement more accurate.
Comments on Homework Assignments
Reading from the Class Notes
Downloads
Prep Assignments and Homework
Handouts
Quiz Grades and Other Grade Info
Quizzes