Concise Definition - Introduction to Microelectronic Circuits - Exam, Exams of Microelectronic Circuits

Download Concise Definition - Introduction to Microelectronic Circuits - Exam and more Exams Microelectronic Circuits in PDF only on Docsity! 1 EECS 40, Fall, 2004, Midterm 2, White EECS 40 Midterm Exam II Fall 2004 Print Name (Last,First) _______________________________________________ Sign Name_________________________________________________________ Do not begin exam until you are instructed to start. Note that there are several versions of this exam in the room. To get credit for a problem, make your method clear to the grader. 1 /24 2 /16 3 /15 4 /22 5 /23 Total /100 2 Problem 1 (24 points) General Questions a. [1] Give a concise definition of the properties of an acceptor atom that could be used in a sili- con wafer and explain what it does. b. [1] What is the power of 50 watts in decibels referred to a reference power of 1mW (this is often referred to as dBm)? c. [1] Identify clearly the meaning of the acronym rms. d. [1] What component can you use to couple a time-varying signal to an amplifier yet keep steady currents from flowing into the amplifier? __________________ e. [1] List two components that can form a circuit that acts as a frequency filter. ____________ and _____________ . f. [1] Draw a simple analog circuit that employs negative feedback (make clear where the feed- back appears). g. [5] List in the table below different devices that are essentially just semiconductor diodes, and indicate their functions: Table 1: Diodes Name of diode Device Function of diode device (give distinguishing functions, being as specific as you can) 1. 2. 3. 4. 5. 5 e. [4] Find the time constant for this circuit. d. [4] Find an expression for vC(t) for t>0, and sketch it below 6 Problem 3 (15 points) Op-Amps a. [7] The op-amp in the circuit below is ideal except that it has a finite gain A. If the measured voltages indicated are found to be vin = 4.000 V and vout = 5.000 V, with R1 = 1 MΩ and R2 = 3 kΩ, what is the value of A? b. [8] For the (ideal) op-amp circuit below find I, vx/vin and vout/vin. R1 = 6 kΩ, R2 = 6 kΩ, R3 = 5 kΩ, R4 = 3 kΩ. Assume that vin = 6 mV. 7 Problem 4 (22 points) Diodes Each of the diodes in the following circuits is ideal. a. [6] Find I and V for this circuit (R = 8 kΩ, V+ = +4 V, V- = -3 V) b. [8] Find I and V for this circuit (R = 3 kΩ, V1 = +1 V, V2 = +3 V, V3 = -3 V) and indicate which diodes are conducting and which are not conducting. c. [8] The voltage vin in the circuit below is a 1 kHz, 10 V peak-to-peak sine wave. I = 2 mA, V2 = +10 V, R = 1 kΩ. Sketch the waveform resulting at vout and indicate the values of the positive and negative peaks. 10 c. [2] Identify the terminals of the MOSFET. d. [4] Draw the load line on the plot and find the Q point (IDQ, VDSQ). IDQ = _________ A VDSQ = _________V e. [4] Assume that you are considering using this circuit as an analog amplifier and are worried about distortion of the signals. For a positive excursion of vin of 0.5 V how much does vout change (positive or negative)? For a negative excursion of vin of -0.5 V how much does vout change (positive or negative)? vout for positive excursion of vin: ________V vout for negative excursion of vin: ________V (continued on next page) 11 g. [4] Draw a simple two-component circuit that represents this MOSFET under the following two extreme conditions: VGS – VT > 0, VDS < VGS – VT: VGS – VT < 0: