EE 2212

PROBLEM SET 1

S. G. Burns

Due: 25 January 2017

Ø Unless otherwise announced, I will collect the problem set when I collect the associated quiz. It is also important to note that I often use homework problems as part of the weekly quizzes. In collaboration with Karin Larson (UGTA-Undegraduate Teaching Assistant), some or all of the problems on each problem set will be graded. Quiz coverage will include material related to, and supporting the problem set as well as material covered in class through the previous class period, usually through Monday’s material. Any additions or deletions from quiz topical coverage will be announced in class, via e-mail, and/or on the class WEB page. I strongly encourage you to ask questions about the homework problems during class and during office visits. I also encourage you to ask for assistance on any underlying and supporting topics from other courses. You may work together, and I encourage you to do so, but remember you, and you alone, are responsible for your work and you must turn in homework individually unless otherwise noted. Material from laboratories may also be incorporated in a quiz.

Ø ALL QUIZZES are open book and notes. Laptops and tablets are OK, also WEB access. Be careful on time management when using the WEB during the quiz time. Be sure and bring your completed problem set to class.

Ø Unless otherwise noted, I use the two-person team quiz active learning/cooperative learning pedagogy format. Please identify your quiz partner in advance. It makes sense to also have that same person as your laboratory partner although that might not work out if you are in different laboratory sections.

Ø You may also elect to take quizzes individually if that better suits your learning style. Please let me know in advance so that I can prepare an adequate number of copies.

Ø QUIZ 1, nominally 25 minutes long, will be given on Wednesday, 25 January, during the last portion of the class period.

Ø Also, take the opportunity to study the text "Examples", which includes solutions.

Ø I also encourage that you read the Preface in the text to provide a broad perspective on what topics are included in the text.

Ø Be aware that you may often use different approximations and approaches to the problem solution which may result in somewhat different (but very correct) answers. Apply your skills in engineering to evaluate the correctness of your answer and solution method should there be a perceived discrepancy. One of my favorite sayings is, “Look at you results with an engineering eye”.

Ø You will need and use SPICE/PSPICE in EE 2212. You may already have a copy from EE 2006. An evaluation version of SPICE (PSPICE) is available from http://www.engr.uky.edu/~cathey/pspice061301.html or from ORCAD http://www.cadence.com/products/orcad/pages/downloads.aspx . The link http://www.pspice.com/ will also work.  Version 16.1 also works.  The labs use version 9.1. Be sure you have a decent broadband connection for a personal download. PSPICE is also available on EE computers including those in MWAH 102 and MWAH 391. Unfortunately, there is no version of SPICE for iOS, only WINDOWS based machines. I keep looking for iOS versions. SPICE will work on an iOS machine if you install a WINDOWS emulator.

Ø One other issue which you should be aware of. I use SYMBOL font in MSWORD, and ADOBE fonts, as needed, in preparing WEB documents. I also use IE as my WEB browser. One reason I use MS WORD and IE is that they are available through ITSS and are supported by UMD. There are cases where your personal generic WEB browser and word processing program may not interpret SYMBOL font correctly. This is especially true for “shareware” and non-standard versions of word processing programs, including Open Office, and versions of some operating systems such as Firefox. Safari (Apple computers and the iPAD) also has some issues. For example the Greek Omega symbol for ohms which should print out as the Greek symbol Ω could print out as a W. This would occur if your printer driver and/or word processing and/or font utility within your WEB browser were not set up to accept SYMBOL, or in some cases ADOBE fonts. To the best of my knowledge, all the EE computers using IE and MS products and printers are OK but your personal system may not be. Please let me know if you have this difficulty so I can try and work on fixes with you.

1. Text 1.2, 1.3, 1.4, and 1.8 as a combination. “Moore’s Law” plug-and-chug calculations; also a bit of practice in working with exponentials. Do some WEB surfing and compare your 2020 and 2021 numbers to what is now commercially available in late 2016 and early 2017 for both the number of transistors in a microprocessor and memory bits/chip. INTEL, Amdahl, Micron, and Apple products have some of this information as far as these three problems are concerned. Text 1.8 is another “Moore’s Law” type question to think about. This reality check discussion question is interesting. Look at your numbers and units! Compare to the approximate lattice spacing in a silicon crystal of 5.3 Å. Speculate on how the semiconductor industry could address this fundamental physics issue.

2. Text 1.44 This is a 3-bit Digital-to-Analog Converter. To do this, you will need the basic inverting operational summing amplifier from EE 2006.

This is the Part (c) table to fill in.

Digital Input	Analog Output
000
001
010
011
100
101
110
111

Part (d) as an addition which expands upon Text 1.44 concepts. A realistic problem since most of our digital “toys” use 8-bit digitization for each color in a display or camera. For example, your smart phone or laptop display consists of three colors-red, green, and blue. If each color is digitized with 8-bit resolution, how many different colors can be displayed? What is your opinion on whether the human eye can differentiate this number of colors?

Now several problems in review of circuit analysis techniques from EE 2006. If any of the basic circuit concepts from EE 2006 are a bit rusty, please ask questions either in class or stop in my office. Also note that Experiment 1, 19 January,

will also lean heavily on understanding of EE 2006 topics.

3. Text 1.21 and Text 1.22. Some plug-and-chug practice with Ohm’s Law with an input independent voltage source. Observe that fewer errors occur if you first solve the problem symbolically before you substitute numbers.

So far you have solved Problem 3 with independent voltage sources. The next problem addresses dependent sources. This problem includes independent voltage and current sources , and dependent current generators. Derive an expression for the Thevanin equivalent circuits at the indicated nodes.

4. Text Problem 1.25 and Text Problem 1.28 as a combination. Use symbolic notation; that is do not substitute numerical values for the circuit elements; use the element names such as R₁, g_m, etc. You need not provide numerical solutions.

5. Let’s think about electrocution!!! You were out partying with one of your electrical engineering student friends (Best Friend Forever-BFF) from an unnamed large university located in the Twin Cities. After the bars closed at 2 am your “BFF” thought he was doing you favor and wired up a standard duplex outlet for your apartment as a favor for buying a pitcher or two. Unfortunately, besides not doing well in the large unnamed university in the Twin Cities equivalent to EE 2006 circuits course, and under the influence of a large quantity of a variety of beverages, your “BFF” decided not to follow the National Electric Code. (U.S. standards) Your “BFF”(?), made four errors, three of which could potentially electrocute you!

(a) Describe the four errors and explain how you must fix them. You can mark up the diagram appropriately or provide a separate series of diagrams.

(b) Identify the three potentially fatal errors and explain why they could lead to your

Electrocution (Be sure your tuition is paid up).

(c) Your friend, who will probably get an F in the circuits class, decides to demonstrate his

circuits class knowledge by plugging in a

lamp. Will the lamp work? (YES, NO, PARTIAL INTENSITY, EXPLODE) Circle your

choice and explain your answer.

6. Write peak and rms phasor notation (cosine reference) expressions for the following signals. Sketch the resulting phasor on the complex plane at t=0.

(a) V₁(t) = 100 cos (500 t + 30°)

(b) V₂(t) = 200 cos (500 t) + 100 cos (500 t + 30°)

(c) V₃(t) = 100 cos (1000 t) + 100 cos (500 t + 30°) Be careful! Explain why this is a trick question. At least I warn you about trick questions!

Now write the time domain function, assuming 60 Hz operation for the following rms phasors; repeat if these two

expressions are peak phasors. Reminder that ω = 2πf.

(d) V_a = 100Ð30°

(e) V_b = 100

Now for the important stuff from my extensive files of stuff. I hope you can handle it without getting sick