EE 2212

PROBLEM SET 1

S. G. Burns

Due: 30 January 2013

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 Sukriti Subedi (GTA-Graduate 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 included.

Ø ALL QUIZZES are open book and notes. Laptops and tablets are OK but no WEB access. Be sure and bring your completed problem set to class.

Ø Unless otherwise noted, I use the two-person team quiz active 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. You may also elect to take quizzes individually if that better suits your learning style. Please let me know in advance so that I prepare an adequate number of copies.

Ø QUIZ 1, nominally 20 minutes long, will be given on Wednesday, 30 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 to provide a broad perspective on what topics are included in the text.

Ø Observe that that there are student resources available on the publisher’s WEB site. Also be aware that you may often use different approximations and approaches to the problem 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.

Ø You will need SPICE/PSPICE. You may already have a copy from ECE 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 . 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.

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. There are cases where your personal 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 and versions of some operating systems such as Firefox. For example the Omega symbol for ohms which should print out as the Greek symbol W 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.

First 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 (i.e., Ohm’s Law, linear superposition, Phasors, Kirchoff’s Laws, handling of independent and dependent sources, loop and nodal analysis, etc. ), please ask questions either in class or stop in my office.

1. Text 1.21 Some plug-and-chug practice with Ohm’s Law with an input independent voltage source.

2. Text 1.23 Some plug-and-chug practice with Ohm’s Law with an input independent current source.

3. 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 (1000 t + 30°)

(b) V₂(t) = 100 cos (1000 t) + 50 cos (1000 t + 60°)

(c) V₃(t) = 100 cos (1000 t) + 100 cos (500 t + 60°) Be careful! Explain why this is a trick question.

Write the time domain function, assuming 60 Hz operation for the following rms phasors.

(d) V_a = 250 Ð30°

(e) V_b = 250

4. Fill in the the table for a correctly wired duplex outlet (U.S. National Electric Code standards) where v_ba(t) = 155 cos(377t + 30) volts

5. An electrical engineering student friend from an unnamed large university in the Twin Cities did you a favor and wired up a standard duplex outlet for you. Unfortunately he did NOT follow the National Electric Code. (U.S. standards) Your “friend”(?) made four errors, three of which potentially could kill 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.

(c) Your friend, who will probably get an F in his circuits class, decides to demonstrate his work by plugging in a

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

your answer.

6. Text Problems 1.25 and 1.26 for Circuit (b) only). These two problems include independent voltage and current sources , and dependent current generators. Before you substitute to obtain numerical values, derive an expression for the Thevanin equivalent circuits at the indicated nodes.