EE 230 Electronic Circuits & Systems Spring 2020

May 10, 2020

Scores for Exam 3 have been posted to Canvas. Links to the solutions are on the quiz page. The average score was 32.9 out of 40.

May 5, 2020

Solutions to many of the diode, BJT, and MOS quizzes given since spring break (and relevant to Exam 3) have been posted.

Here is the solution to exam 3 from last year. Also, the solutions to HW 10 have bee posed — see the links in MOSFET section at the bottom of the homepage.

May 3, 2020

Solutions to HW problems D2 and D3, and B1 - B5 have been posted. Solutions to HW problems M1 - M5 will be posted Tuesday morning.

May 2, 2020

Reminder: The third exam for EE 230 is scheduled for Wednesday, May 6, starting at 7:30 a.m. (Bleh.) This is the time set by the Registrar. Of course, finals are normally for two hours, but we will extend the time to four hours, given the strange days that we are living through. I will email the exam to everyone at 7:30 a.m. You can start whenever you want. You will need to return the exam by uploading to Canvas or emailing the pdf to me before 11:30 a.m.

If you have any issues that will affect your ability to take the exam at that time — far-away time zones, technology limitations, clashing exam schedules, or anything else outside of your control — please let me know right away so that we can make adjustments for you. (Unfortunately, "Not being prepared." is not a mitigating factor.)

Here is Exam 3 from last year. You can use this in your preparations. I will post solutions to this old exam in a couple of days.

On a related note, I posted the solutions to Exam 2 a while back — perhaps you have already stumbled across them. The links are on the quiz page of the web site. I have asked the Lab TAs to help in grading some of those. So your Exam 2 score should show up on Canvas sometime "soon", depending on when your TA has time available to get through them.

As always, if you have questions, be sure to ask.

Apr 29, 2020

The MOS SpiceLab is available, if you are interested in doing it. To re-iterate, the three SpiceLabs now form a smorgasbord — do two out of three. If you have already done both the diode and BJTs labs, then you are finished. If you have finished the only diode lab, then you can choose either the BJT or MOS lab — I think they involve a similar amount of work, so it is really a matter of which you prefer. If you haven't done any labs yet — well, you should probably get started. Finally, if you have the time and inclination to do all three labs, then the third lab will be treated as extra credit to boost your total lab score.

The last part of HW M5 is unreasonably difficult to do in an exact form. So I have offered up three alternative methods for solving it. If you have been struggling with that one, take a look at the commentary that I've added to do that problem, and try one of my proposed approaches, any one of which should be simpler than trying to do it exactly.

Since I'm in a good mood, I'll extend an extra HW freebie to everyone. If you would like a bit more time to finish the HW, or would like more time to finish your 400 other projects, you can extend the HW submission time through the weekend.

Apr 27, 2020

SpiceLab news: I realize that SpiceLabs are challenging. They are certainly challenging for me to create. And, while running the simulations should be pretty "straight-forward", the quirkiness of the SPICE programs and everyone's general unfamiliarity with them make the work challenging for you, too. On top of that, we are running out of time. I've been pondering how create enough material for people to learn about electronics while still being reasonable under the unusual circumstances. In light of my own concerns, here are a couple of changes regarding the SpiceLab work:

Hopefully, that makes things a bit easier for everyone to plan their last two weeks.

A new versions of quiz 28 and a first version of quiz 29 ready to go. Quiz 29 (The last one!) will have both NMOS and PMOS transistors, either in two separate circuits, or possible a single circuit with both types of transistors together.

Apr 26, 2020

The dreaded SpiceLab 8 has landed. See the schedule page — hover the cursor trepidatiously over link before clicking.

Apr 25, 2020

New versions of quizzes 27 and 28 are loaded and ready to go. Reminder: Today is the last day for quiz 27.

Apr 24, 2020

The final homework set has been posted. It is due on May 1.

Apr 22, 2020

Quizzes 26 (round 3) and 27 (round 1) are available to take today at 4:00.

Quiz commentary: Quiz 26 is (meant to be) quite easy. Quiz 27 is harder. Note that you should be able to handle an NMOS circuit that requires solving a quadratic equation — either the NMOS is in ohmic mode, there is a resistor voltage included in vGS, or some other weirdness. Get your calculator set up to do the work of solving quadratics for you. Although all the examples show the tedious math to solve the quadratic equations by hand, it is not necessary to do that for quizzes, etc. Set up the relevant KVL or KCL equation from the circuit, and let the calculator do the work. As always, you should check your answers — plug them back into the circuit to confirm that everything checks. Of course, if you really like doing quadratic algebra by hand, that's fine — solve away!

Reminder: HW set 9 is due today. Upload on Canvas before midnight. If you are using a freebie, you will need to send your pdf to me by email.

Apr 21, 2020

The missing homework B3 has been found. You can check it out via the schedule or homework pages.

Apr 20, 2020

Reminder: Today is the last day to take quiz 25.

Now we move from the BJT era to the MOSFET era. Of course, that means that we are getting close to the end of EE 230 WooHoo! For the adventurous, the first NMOS quiz can be taken today.

Quiz comments

Apr 18, 2020

Reminder: Today is the last day to take quiz 24. No quizzes tomorrow. Monday is the last day to take Quiz 25.

Apr 16, 2020

There is a new version of the pnp quiz (Q24) ready to go. Also, as final salute to BJTs, there is Quiz 25, which consists of either two separate (but possibly related) BJT circuits — any combination of npn/pnp and FA/sat — or a single circuit that has 2 or more BJTs in it. When you are feeling good about BJTs (Does that ever happen?), you should try Quiz 25. There will be versions available between today and Monday.

Apr 15, 2020

There are a handful of pnp practice problems available. I realize that it is short notice, but if you wanted to try Quiz 24 today, which will have pnp transistors, you can practice a bit before hand. Of course, there are a few more days to take Quiz 24 after today.

Also, note that today is the last day for quiz 23.

The long anticipated SpiceLab 7 has arrived. Along with (most of ) HW set 9.

Apr 14, 2020

There is a slight change in the schedule today. I'm not quite ready for a pnp BJT quiz, and I assume that most of you are not either. So the start of pnp quizzes is delayed until tomorrow, and the last day for those will be Saturday. I've updated the schedule page to reflect that change.

Apr 13, 2020

New versions of Quizzes 22 & 23 are ready to go. Reminder: Today and tomorrow are your last opportunities to take Quiz 22.

I've re-written the notes for BJT saturation — I think the new version is more readable, particularly in the justification for vCE(sat) = 0.2 V. Be sure to re-read if you are getting ready to take Quiz 23. The notes are a bit short on examples — I will try to add a few more when I get a chance.

Apr 11, 2020

A new version of Quiz 22 is loaded into the quiz cannon and is ready to fire out at 4:00 p.m. The first version of Quiz 23 is also in the breech and ready to launch. Show up at 4:00 if you would like to try to catch either of these.

A note on the differences between 22 and 23: All of the circuits on the two quizzes have the same forms — an npn BJT with some resistors and power supplies attached. In Quiz 22, the BJTs are guaranteed to be operating in forward-active mode. In principle, you don't even need to check, although you end up checking anyway due to the values that I ask you to calculate. In quiz 23, saturation mode is added to the mix — you can be assured that one or both of the circuits has its transistor in saturation. You need to check and confirm your assumed mode of operation. The next round of BJT practice problems that are showing up are the proper place to prepare for Quiz 23. The circuits are the same as in the previous set of BJT practice problems, but now the possibility of saturation is included. Roughly half of the circuits that you ring up will be in saturation. And a small number will be "off", characterized by not having enough base voltage to forward bias the base emitter junction.

You have surely noticed that the practice problems have changed somewhat. Rather that having one giant script that randomly generates different circuits and different values, I have split the scripts so that each one has only one circuit. The scripts are numbered. When you click (or refresh) on a particular number, you will always get the same circuit, but with different component values each time. I've tried to arrange the sequence so that the circuits get harder as the numbers get bigger — for example, circuit 6 should be somewhat trickier than circuit 1. It is not a hard rule, but that is the general trend that I'm trying to achieve. Hopefully this approach will allow you to work a bit more effectively. First, read the notes. Then start on the corresponding set of practice problems, working your way from 1 on up. Do several examples of each circuit to make sure that you have it mastered. Then go to the next. When you are able to work the highest numbered problems, you are probably fairly proficient and ready to take the corresponding quiz. With the new arrangement, if you are stuck on solving any particular circuit, you can focus on that one until you figure it out or can send out a call for assistance. With the old arrangement — one giant script — if you wanted to focus on a particular circuit that was vexing you, it was necessary to madly hit refresh until the probability gods deigned to serve up that particular circuit. And then it would probably have the wrong values. (Also a factor: the new approach makes it easier for me to write and de-bug the scripts.)

Apr 10, 2020

Don't forget that homework 8 is due today. There is an assignment link in Canvas where you can upload your scanned HW solution. That door closes at 11:59 p.m. (I note that about 25 people have already submitted — nice!) If you have late freebies still available, you can use one of those and submit the work on Monday. In that case, you will have to email your pdf to me rather than submit to Canvas. If you don't have any freebies left and you won't be able to finish the homework, then you should contact me. We will see how effective groveling is when done on-line...

Quiz news

Apr 9, 2020

Diode quizzes are done, and we are entering in bipolar junction transistor (BJT) quiz epoch. If you are ready, the first BJT quiz is available today. Of course, there will be several more days to take this initial quiz. I need to adjust the general timing of quizzes so that I'm not making so many different quizzes every day — I'll post a revised quiz schedule later today.

Apr 7, 2020

Reminder: You do not need to send me emails requesting quizzes. I am no longer emailing those out. When you are ready to take a quiz on a particular day, go to Canvas at 4:00 p.m. — a fresh version of each current quiz will be waiting for you there.

More example calculations have been added to the on/off diode example notes. I won't make any further changes to these notes.

Apr 6, 2020

Monday versions of quizzes 19, 20, and now 21 are ready to go. Take one at 4:00 p.m., if you are so inclined.

All of you who have been fretting about homework problems can now rest easy. The problems for HW set 8 are now available. The due date is Friday. Check the schedule or homework pages. (Actually, now is the time to start fretting about homework, because there is now work to be done. All of you who have been concerned about the lack of homeworks should consider the related concepts of "Let sleeping dogs lie." and "Don't poke the monster with a stick." HaHa!)

Apr 4, 2020

"Notes" news – I have added the start of a new set of notes with examples of diodes circuits analyzed using the on/off method. There are only two complementary examples there now, but I will add more over the next couple of days. If you are still a bit puzzled by the whole "on/off approach", take a look at what's there now and check back again later after I've added more examples — I think these might be helpful.

Quiz news

Apr 2, 2020

Solutions to homework problems OA7 - OA16 have been posted.

A new version of Quiz 19 and the first offering of Quiz 20 will both be available at 4:00 today. Note that there will be no quizzes tomorrow — presumably most of you will be busy with other matters.

Apr 1, 2020

Exam information

The next version of Quiz 19 is ready, for those of you who are ready to try it. You have a few more days, if you aren't ready yet.

More quiz information

Mar 31, 2020

Quiz news

Mar 26, 2020

I updated the drift/diffusion practice problems. They have been split into two separate scripts — one for drift and one for diffusion. If you are getting ready for Quiz 18, be sure to use the diffusion problems. Also, I added one more type of problem to the drift script — there is now an option that asks for a calculation of current density. This type of question might show up on future versions of quiz 17.

Mar 25, 2020

I sent a long a email explaining how we will do quizzes. Please read it all and make sure that you understand the procedure. If you have questions, be sure to ask before you take the quiz or before the deadline passes for the first quizzes.

The Canvas gizmo for the class is active. Right now, the only thing I intend to use it for is uploading quizzes, homeworks, etc. I don't plan to duplicate anything that is already being done with usual web site to Canvas. As I become more familiar and comfortable Canvas, I may invoke more features. As our fearless leader likes to proclaim, "We will see."

I goofed up with the quiz numbering. Our last in class quiz was #16, so our first "remote" quiz should be #17.

Mar 24, 2020

I’ve fixed up some of the issues with the drift/diffusion practice problem script. Right now it works fine for drift (resistor) problems. I will add the diffusion problems in later.

The revised schedule with the module listing has been posted. Have a look. I'll give more details about how to do the quizzes in a later post. Note that the drift/diffusion practice problems need to be updated — the script is sort-of usable now, but it needs a bit of maintenance work.

Mar 23, 2020

After giving it some thought over the past week, I’ve come to the conclusion that we need to go as asynchronous as possible.

I will also use this time to do some experimentation with online teaching. As I experiment, I will try to keep things as simple as possible for you. But be advised that the methods may change over time.

Here is what I know for sure.

Whew! I’ll have more info tomorrow, including the revised “module list”.

Stay healthy everyone!

Old stuff