Circuit - Introduction to Microelectronic Circuits - Exam, Exams of Microelectronic Circuits

Download Circuit - Introduction to Microelectronic Circuits - Exam and more Exams Microelectronic Circuits in PDF only on Docsity! EECS 40 Midterm #1 Fall 2001 Professor Oldham Guidelines: 1. Closed book and notes except 1 page of formulas. 2. You may use a calculator 3. Do not unstaple the midterm. 4. Show all your work and reasoning on the exam in order to receive full or partial credit. 5. This exam contains 6 problems and corresponding worksheets plus the cover page. 6. Do not ask questions during the exam. If you believe there is an error, please point it out. If you believe there is an ambiguity, explain your interpretation in your answer. Problem 1 (15 points) Hint: Use the easiest possible method to solve these problems. (a) In the circuit below, find VA, VB, VC. (b) In the circuit below, find VA, VB, VC. lmA 2V Qs Qe VA + 1K@ 2V C) A 1KO 1K&  (e) Write an equation for VC(t). Problem 3 (17 points) A three-digit binary number ABC has "even parity" if an even number of its digits is 1 or none of its digits is 1. We define a logic variable E that is 1 if ABC has even parity. (a) Write a truth table for E, that is, the combinations of ABC having even parity. (b) Write a Boolean expression in sum-of-products form for E. (c) Draw a logic circuit for E, constructed only of inverters, OR gates, and AND gates. (d) Draw a logic circuit for E, constructed only of NAND gates and inverters. Problem 4 (16 points) - Nodal Analysis (a) In this problem you are to use nodal analysis to find a set of equations enabling you to find the values of VX, VY, VZ, and VW. First, identify which of the four are really unknown node voltages and secondly, write sufficient equations to find the four values. Hint: If, for example, two of the voltages are known, you first write these two values (known node voltages), then you would need twp nodal equations for the two unknowns. NOTE: DO NOT solve the equations. (b) Being a smart Cal student, you think it is wise to check out the work of the high-paid Stanford engineer. Can you write down the logic expression for Y and for F? To get full credit you must derive and simplify the logic expression and you must show all of your work. Problem 6 (15 points) (a) You find a tremendous bargain on a transmogrifier at a flea market. You do not know what it is, but it's a great big black plastic box with two terminals and it's labeled "type 1 transmogrifier," and most importantly, the price is 50 cents. You take it home and measure its I- V characteristics and plot I versus V, as shown. Now your lab partner connects the device into the circuit shown and you find the box gets warm. How much power is the transmogrifier consuming when connected this way? (b) Wanting to learn about the effects of electricity on exhausted college students, you prepare the experiment shown. At the output terminals, labeled "O" and "G", you intend to hook up your roommate, Charlie. You have already determined that when a suitable moist connection is made, your roommate behaves electrically like a resistance of 1K ohm. The idea is that you will first set some suitable value of VSS, and flip the switch from the left to the right (i. e., charging the capacitor, and then discharging it into your subject.) If there is no response, you repeat the experiment but at a larger value of VSS. You keep on increasing the value of VSS until you elicit a response. (Then you run.) (b.1) Suppose Charlie has a response at a voltage of VSS = 1KV. How much energy are your delivering to him in one pulse under such conditions? (b.2) What is the efficiency of your energy delivering process, in other words, what fraction of the energy taken from VSS is delivered to Charlie? (b.3) How long should you keep the switch to the left to be sure that you have charged the capacitor to exactly 99% of the value of VSS? (Assuming the capacitor is initially uncharged.)