Ernest M. Kim

Exploring the Basic Principles of Electric Motors and Generators With a Low-Cost Sophomore-Level Experiment

In order to meet changing curricular needs, an electric motor and generator laboratory experience was designed, implemented, and assessed. The experiment is unusual in its early placement in the curriculum and in that it focuses on modeling electric motors, predicting their performance, and measuring efficiency of energy conversion. While subfractional-horsepower electric motors and a primitive, but unique, small-scale dynamometer were used, experimental results proved to be reliable, accurate, and repeatable. The change in student knowledge and confidence in the application of that knowledge was assessed and shown to have increased significantly in both cases.

Engaging Students in Applied Electromagnetics at the University of San Diego

Two possible topical approaches that have been applied to teaching an upper-division undergraduate electrical engineering applied electromagnetics course are presented. Each approach was applied to one of two offerings of the course, taught in different semesters. In either case, the course includes the study of electromagnetic theory and practical applications through laboratory experiments, design and projects. Using basic theory in time-harmonic electromagnetic fields developed early in the course, two different applications of the theory are emphasized in two alternate semesters of the course offering. The two applications that incorporated the common theoretical background of the course are: (1) applications in radio frequency engineering; and (2) radar and antenna design. An extension of the course to a topic beyond the confines of the course textbooks is included. The success of the course is further realized in two industry-sponsored capstone senior design projects.

Exploring Three-Phase Systems and Synchronous Motors: A Low-Voltage and Low-Cost Experiment at the Sophomore Level

In order to meet changing curricular and societal needs, a three-phase system and synchronous motor laboratory experience for sophomore-level students in a wide variety of engineering majors was designed, implemented, and assessed. The experiment is unusual in its early placement in the curriculum, and in that it focuses primarily on basic understanding of balanced three-phase systems and synchronous motor operating principles. While a low-voltage three-phase system and subfractional-horsepower electric motors were used, experimental results proved to be reliable, accurate, and repeatable. Changes in student knowledge and confidence in the application of that knowledge was assessed and shown to have increased significantly in each case.

A Short Study on the Validity of Miller's Theorem Applied to Transistor Amplifier High-Frequency Performance

The use of Millers theorem in the determination of the high-frequency cutoff frequency of transistor amplifiers was recently challenged by a paper published in this transactions. Unfortunately, that paper provided no simulation or experimental results to bring credence to the challenge or to validate the alternate method of determination proposed. This paper provides SPICE simulation results that validate the common usage of Millers theorem, limit the alternate method provided in that recent paper to a very small class of amplifiers, and reinforce the need to consider transistor amplifiers as two-pole systems.

A low-cost design experience for junior-level electronics circuits laboratories through emulation of industry-printed circuit board design practice

Over a 2-year period, printed circuit board layout design and test were included in the laboratory portion of the second of two junior-level electronic circuits courses. Printed circuit board design using industry-accepted board specifications and standard industry Gerber file export experience was developed. The students’ printed circuit board design experience emulated real-world situations and cost criteria. The instructor served as the fabricator in this model of the industrial design situation. Students individually used industry standard schematic capture and layout software to develop a printed circuit board for a simplified discrete µA741 operational amplifier. The layout designs were submitted as industry standard Gerber files electronically to the instructor/fabricator for evaluation. Grades were assigned by evaluating the accuracy and cost effectiveness of the design by minimizing traces, reducing printed circuit board geometry, and limiting the number of vias, which ultimately reduces fabricator tooling cost. Feedback was provided by the instructor who acted as the industry fabricator to individual students. A single fabricated printed circuit board, designed by the instructor (and fabricated by a commercial printed circuit board manufacturer), was delivered to students for assembly and test. By delivering a single printed circuit board design to students, fabrication costs can be minimized and students can inspect the delivered board as an exemplar. Assessments of the student perceptions of knowledge of and confidence in applying printed circuit board techniques in designing and releasing a printed circuit board were conducted prior to and after the printed circuit board layout design and test. On a 5-point scale, overall student-reported knowledge increased by 2.14 and overall student confidence increased by 1.20 points. Faculty assessment of knowledge, as measured by scoring short answers to knowledge statements, correlated well with student report and showed an average increase of 2.70.

Fundamentals of Electronics: Book 4 Oscillators and Advanced Electronics Topics

This book, Oscillators and Advanced Electronics Topics, is the final book of a larger, four-book set, Fundamentals of Electronics. It consists of five chapters that further develop practical electronic applications based on the fundamental principles developed in the first three books. This book begins by extending the principles of electronic feedback circuits to linear oscillator circuits. The second chapter explores non-linear oscillation, waveform generation, and waveshaping. The third chapter focuses on providing clean, reliable power for electronic applications where voltage regulation and transient suppression are the focus. Fundamentals of communication circuitry form the basis for the fourth chapter with voltage-controlled oscillators, mixers, and phase-lock loops being the primary focus. The final chapter expands upon early discussions of logic gate operation (introduced in Book 1) to explore gate speed and advanced gate topologies. Fundamentals of Electronics has been designed primarily for use in upper division courses in electronics for electrical engineering students and for working professionals. Typically such courses span a full academic year plus an additional semester or quarter. As such, Oscillators and Advanced Electronics Topics and the three companion book of Fundamentals of Electronics form an appropriate body of material for such courses.

Fundamentals of Electronics: Book 3 Active Filters and Amplifier Frequency Response

This book, Active Filters and Amplifier Frequency Response, is the third of four books of a larger work, Fundamentals of Electronics. It is comprised of three chapters that describe the frequency dependent response of electronic circuits. This book begins with an extensive tutorial on creating and using Bode Diagrams that leads to the modeling and design of active filters using operational amplifiers. The second chapter starts by focusing on bypass and coupling capacitors and, after introducing high-frequency modeling of bipolar and field-effect transistors, extensively develops the high- and low-frequency response of a variety of common electronic amplifiers. The final chapter expands the frequency-dependent discussion to feedback amplifiers, the possibility of instabilities, and remedies for good amplifier design. Fundamentals of Electronics has been designed primarily for use in an upper division course in electronics for electrical engineering students and for working professionals. Typically such a course spans a full academic year consisting of two semesters or three quarters. As such, Active Filters and Amplifier Frequency Response, and the first two books in the series, Electronic Devices and Circuit Applications, and Amplifiers: Analysis and Design, form an appropriate body of material for such a course.

Fundamentals of Electronics:Book 1 Electronic Devices and Circuit Applications

This book, Electronic Devices and Circuit Application, is the first of four books of a larger work, Fundamentals of Electronics. It is comprised of four chapters describing the basic operation of each of the four fundamental building blocks of modern electronics: operational amplifiers, semiconductor diodes, bipolar junction transistors, and field effect transistors. Attention is focused on the reader obtaining a clear understanding of each of the devices when it is operated in equilibrium. Ideas fundamental to the study of electronic circuits are also developed in the book at a basic level to lessen the possibility of misunderstandings at a higher level. The difference between linear and non-linear operation is explored through the use of a variety of circuit examples including amplifiers constructed with operational amplifiers as the fundamental component and elementary digital logic gates constructed with various transistor types. Fundamentals of Electronics has been designed prima ily for use in an upper division course in electronics for electrical engineering students. Typically such a course spans a full academic years consisting of two semesters or three quarters. As such, Electronic Devices and Circuit Applications, and the following two books, Amplifiers: Analysis and Design and Active Filters and Amplifier Frequency Response, form an appropriate body of material for such a course. Secondary applications include the use in a one-semester electronics course for engineers or as a reference for practicing engineers.

A laboratory exercise to improve student understanding of dominant pole analysis and high-frequency modeling of Field Effect Transistors

In the quest for increased student understanding of the principles underlying high-frequency response of Field Effect Transistor amplifiers, a laboratory exercise employing a unique method to determine the intrinsic transistor model capacitances was used. The method employs two simple measurements: determination of the high 3-dB frequency for a common-source amplifier being driven by a Thévenin source with two different output resistance values. Circuit simulation results utilizing these experimentally determined intrinsic capacitances show much greater correlation to experimental results than those typically obtained using manufacturer-supplied values. Students participating in the laboratory exercise reported good gains in knowledge levels and reasonable gains in confidence levels.

Effects on return loss due to microstripline radial bends and via density

Straight microstriplines give optimum return loss performance in circuits operating in the 100 MHz to 1 GHz frequency range. Microstriplines that are not straight are typically designed with diagonal (fully mitered) sections or with 90deg bends with mitered corners. It appears that the return loss of non-straight microstriplines with radial bends are superior to diagonal paths. Increased via density also enhances the return loss .