Instructional Demos, In-Class Projects, & Hands-On Homework: Active Learning for Electrical Engineering using the Analog Discovery

Transcription

1 Instructional Demos, In-Class Projects, & Hands-On Homework: Active Learning for Electrical Engineering using the Analog Discovery by Dr. Gregory J. Mazzaro Dr. Ronald J. Hayne THE CITADEL, THE MILITARY COLLEGE OF SOUTH CAROLINA 171 Moultrie Street, Charleston, SC 29409

2 Presentation Overview Motivations for Introducing the Analog Discovery into EE Courses Key Features of the 1 st -Generation Unit Manufactured by Digilent Hardware and Software Analog and Digital Integration of the Analog Discovery into Citadel EE Freshman Introduction to Electrical Engineering Sophomore Circuit Analysis and Digital Logic Results, Feedback, & Summary 2

3 Why use the Analog Discovery? Motivations for Introducing the Analog Discovery into EE Courses (1) to provide hands-on exposure that few EE students receive in the opening semesters of their major (2) to introduce electrical wiring/routing, signals, and components to a student who has not yet studied Ohm s Law (3) to provide a way for students to experiment with relatively-harmless electricity away from the classroom and lab (4) to integrate such a tool across multiple core EE courses (5) to familiarize EE students with a tool that they might use to complete assignments/designs that do not require using the Analog Discovery (6) to accomplish [all of the above] for under $200 3

4 oscilloscope function generator Instrument: Hardware The AD instrument combines the functions of multiple electronics-laboratory instruments into a single USB-powered, PC-controlled, portable unit. voltage supply multimeter 4

5 function generator Instrument: Hardware voltage supply key features: simultaneous +5-V and 5-V fixed supply rails (up to 50 ma) 2 arbitrary waveforms: any DC voltage between 5 V and +5 V sinusoids & square waves up to 10 MHz 5

6 oscilloscope Instrument: Hardware key features: 2 simultaneous analog inputs 100 MSamples/second automated measurements: DC (average) voltage RMS voltage peak-to-peak voltage multimeter 6

7 function generator oscilloscope Instrument: Software All functionality is available through a unified graphical user interface. Waveforms TM fixed power rails 7

8 Instrument: Software All functionality is available through a unified graphical user interface. logic pattern generator Waveforms TM static input/output logic analyzer multimeter 8

9 Instrument: Analog These lines are used in Fundamentals of EE, Electric Circuit Analysis I and II, and Electrical Laboratory. 9

10 Instrument: Digital These lines are used in Fundamentals of EE and Digital Logic Design. 10

11 Freshman Fundamentals of EE A sample exercise from our LED lab: Build the circuit shown in the figure. Measure the voltages V D and V R. + V D - I D 5 V R + VR - Tutorials are available at learn.digilentinc.com. Freshmen become familiar with series & parallel, breadboarding, measurements, and verification of Ohm s Law, KVL, KCL. 11

12 Freshman Fundamentals of EE A sample exercise from our Digital Counter lab: Interface the 74HC161 to the Digital I/O pins as listed in the table. Observe the incrementing of binary numbers. Digital Digital Function IC Pin IC Pin Function I/O I/O DIO 9 MR 1 16 Vcc V+ DIO 10 CP 2 15 TC P Q0 DIO 0 P Q1 DIO 1 P Q2 DIO 2 P Q3 DIO 3 DIO 8 PE 7 10 TE V+ GND GND 8 9 SPE V+ Freshmen become familiar with clocking, base-2, and binary counting. 12

13 Sophomore Electric Circuits MS8217 parts kit All sophomores who take Circuits receive 2 instruments and a set of components. 13

14 Sophomore Electric Circuits Written: Show all work for maximum credit. 1. In Circuit #1, determine the power absorbed by the dependent voltage source. 2. In Circuit #2, determine the voltage v. Simulation: 7. Simulate Circuit #2 in PSpice. Submit a printout of your schematic, showing all node voltages. (Submit this printout attached to the Written portion of the assignment.) Explain why your simulation confirms your answer to Problem #2. Project: 8. Build Circuit #2 using your Analog Discovery design kit. Demonstrate to your instructor that you are able to measure the voltage v using your multimeter. (You only need to bring your breadboarded circuit to your instructor s office.) Sophomores are required to breadboard & demonstrate 1 circuit every week. Circuit #1 Circuit #2 14

15 Lecture w/ Analog Discovery lecture presentation slides overhead-projected screen seen by the instructor, in class white-board breadboard seen by the students, in class multimeter Demonstrations of breadboarding and interfacing with instrument(s) are given by the instructors, regularly. instrument 15

16 Homework Previews The instructors provide example layouts and sample signals before homeworks are due. slides distributed as part of the weekly course notes 16

17 Sophomore Circuits Lab PRE-LAB: Complete the following 9 steps before arriving to perform Lab #1. 1. In PSpice, build and simulate (using Bias Point ) the two-branch voltage-divider circuit shown in Figure 1. Breadboarding performed before each lab begins gives each student more time to perform diagnostics. Figure 1. Voltage divider circuit. 8. Ensure that you have the 5 resistors needed to build the circuit in Figure 1. Using your MS8217 as a DC ohmmeter, measure each resistor, record its true value, and compute percent error from nominal. Ensure that no percent error is greater than 10% before proceeding. 9. Construct the circuit of Figure 1. Add jumpers to your breadboard for the independent voltage source. Use 1 red wire for + and 1 black wire for. 17

18 Sophomore Digital Logic The instructors have found many ways to demonstrate EE concepts using the Analog Discovery, beyond required assignments. A classroom demo of sequential logic replicates the tail-light flashing sequence of a 1965 Ford Thunderbird. The design was written in VHDL and implemented on a Xilinx FPGA using a Digilent BASYS board. Digilent BASYS top row: turn signal & hazard inputs bottom row: tail-light outputs 18

19 Results / Successes Outcomes required by ABET: an ability to apply knowledge of mathematics, science, and engineering -- Students use the Analog Discovery to verify theoretical results given by KVL, KCL, and calculus. an ability to design and conduct experiments, as well as to analyze and interpret data -- Students can now conduct such experiments (partly) on their own time, in their choice of environment. an ability to use the techniques, skills, and modern engineering tools necessary for engineering practice -- Modern EE is performed by comparing simulations against measurements, such as PSpice vs. Analog Discovery results 19

20 Results / Successes Proficiencies demonstrated by our students: in Fundamentals of Electrical Engineering build a resistor-led circuit measure a DC voltage & calculate a DC current build an IC-based counter circuit control digital inputs & observe digital outputs in Electric Circuit Analysis I measure a resistance breadboard a resistive circuit measure multiple DC voltages; measure a DC current build a circuit containing multiple sources / an op amp generate and observe a sinusoid & a square-wave voltage build an RC/RL circuit; observe an exponential rise/decay 20

21 Feedback & Summary Feedback reported by students: from Fundamentals of Electrical Engineering The course did a good job holding my attention. Everything was interesting and hands-on. I enjoyed the hands-on learning style of the labs and lessons. from Electric Circuit Analysis I I enjoyed the demo assignments in the course. Hands-on homework with the breadboard and PSpice was very helpful. I love the Digilent-Waveforms projects as well as the PSpice simulations. This really helped me understand key concepts. Summary: We demonstrated the integration of the Analog Discovery across the early EE undergraduate curriculum. The AD does help to achieve ABET s stated objectives for EEs and has received a positive response from students. 21

22 References [1] Analog Discovery Technical Reference Manual, Digilent Inc., [2] Waveforms SDK manual, Digilent Inc., [3] Beginner Analog Discovery, Module 1, [4] Getting Started with the Analog Discovery, [5] Digilent Basys Board Reference Manual, Digilent Inc.,