Engineering Commons^™

Small Prolate Spheroidal Antenna In A Dissipative Medium., William Troy Cowan

Electrical and Computer Engineering ETDs

A perfectly conducting prolate spheroidal antenna immersed in a conducting medium is analyzed. It is assumed that the dimensions of the spheroid are small compared to a skin depth in the medium. A gain factor for the antenna as a receiver is computed as a function of the spheroid's axis ratio. The prolate spheroid is assumed to be excited by a circular filament of magnetic current located in the plane of the spheroid's minor axes to approximate excitation by a magnetic toroid. Expressions for the antenna's input admittance and effective length are derived. Some experimental results verifying the derivation of …

Thin Film Resistor Deposition, Rollie R. Herzog

Masters Theses

"Thin film techniques may be the key to future miniaturization of electrical equipment. The purpose of this thesis was to develop procedures for deposition of thin film resistors and to test these deposited resistors. Starting with a vacuum system, equipment was designed and built to hold and heat the substrate, monitor the substrate temperature and deposited resistance, and to evaporate the material to be deposited. Resistors were deposited and tested for resistance between resistors, capacitance between resistors, and resistance of resistors. A heat aging test was also used comparing resistors with and without a silicon monoxide coating"--Abstract, page ii.

Design Of A Photoelectric Transient Torque And Speed Meter, Raojibhai A. Patel

Masters Theses

"There are many situations in which it is desirable to know the speed of the shaft and the torque it is transmitting, when it is equally undesirable to make any mechanical connection to the shaft. This thesis describes the development and design of a device for measuring the torque and speed by photo-electric means. The basic principle is that a light beam parallel to the shaft may be used to pick up the desired information without adding friction to the system. The deflection of a torque tube inserted in the shaft opens or closes a set of apertures arranged in …

Active Band-Pass Filters Using Twin-Tee Networks, Terry B. Watson

Masters Theses

"The primary objective of this thesis was the design and construction of a set of filters to determine the spectral energy density of random signal data in the spectrum from 10 cps to 20 kcps. The statement of the problem placed rather exacting conditions on the cost and performance of the equipment, and these conditions were met to the extent detailed in the following pages. A secondary objective was the investigation of techniques to improve the performance of band-pass active filters using resistive-capacitive feedback networks. This objective was not achieved to the author's satisfaction, although several promising ideas were discovered"--Abstract, …

A Study Of The Effect Of Surface Beveling On Silicon Rectifiers, Gary L. Voorhis

Masters Theses

"The problem in this thesis is to experimentally obtain voltage vs distance data for different angles of bevel, to determine the optimum bevel angle on the basis of minimum surface electric field, and also to determine the location of the maximum surface electric field with respect to the p-n junction. Experimental equipment is constructed and results are graphically illustrated. It is concluded that in general the maximum surface electric field decreased as the bevel angle decreased, that neglecting practical considerations the optimum bevel angle was 3⁰, and that the maximum surface electric field occurred near, but not at the p-n …

Measurement Of Stray Load Loss Of D.C. Machines, Kanaiyalal Ramanlal Shah

Masters Theses

"For many years the standard practice, in calculation of conventional efficiency of d.c. machines, has been to include stray load losses as equal to 1% of the output. This assumption may be true for large, compensated d.c. machines but it is known to be small for smaller, uncompensated, general-purpose, industrial-type machines of open design. An A.I.E.E. Committee on Rotating Machines was formed to investigate whether the present practice of assigning 1% for the stray load loss is justified or not. They reached a conclusion, reported in 1949, after investigating 243 stray loss tests on different motors ranging from 1/2 hp …

The Design And Construction Of A Medium Power, Synchronous, Electronic Switch, Floyd S. Hall

Masters Theses

"This paper presents the design and construction of a medium power, synchronous, electronic switch and associated timing and control circuits.

The unit described is capable of controlling a 20 ampere resistive or inductive load from a 110/220 volt, 60 Hz excitation source. Thyristors are used as the active switching elements. The period of the on/off switching cycle may be varied from 1/60 second to 8 1/2 seconds. Turn-on and turn-off may occur at independently selected phase angles relative to the reference frequency source.

Higher power operation could be obtained easily with minor design changes"--Abstract, page ii.

Analog Simulation Of A Synchronous Machine, J. Derald Morgan

Masters Theses

"The problem presented here is a study by an analog computer simulation of a synchronous machine under balanced three phase, short-circuit conditions. The purpose is to obtain a solution that is more accurate than one obtained by approximate methods using transient and subtransient reactances as is often done. This simulation is accomplished by using an idealized synchronous machine. The equations relating voltage and currents in the machine, as well as speed and torque, are presented for simulation. The equations for the machine include the saliency of one member, as well as the effect of speed and the damper windings. A …

A Feedback Compensator Design For Linear Control Systems, Thsai-Ten Lin

Masters Theses

"The compensation process in control system engineering is indispensable. The addition of a compensator to a fixed plant can often make the system meet certain specifications easily. In this study an attempt was made to use a general purpose digital computer to design a feedback compensator. The method developed is first to determine the minimum gain of the amplifier and the number of compensator poles and zeros based on the given specifications. then free hand root-loci are plotted, with several combinations of possible compensation variables. These data are used as the open-loop transfer function from which the poles and zeros …

Circular Polarization From A Corner Reflector Antenna With Tilted Dipole Of Arbitrary Length, Ruben A. Carrizo M.

Masters Theses

"The problem consists of the development of the electric far field equations for a forty-five degree corner reflector antenna with a tilted dipole, of arbitrary length, centered at the corner bisector plane to produce circularly-polarized radiation. The far field expression was developed as a function of the spherical coordinate system variables and placed in Fortran language in order to determine the dipole locations which would produce circularly-polarized radiation. At such dipole locations the field patterns were plotted in the [theta] = [pi]/2 and [phi] = 0.0 planes. Computations were made by the IBM 1620 digital computer"--Abstract, page ii.

On Time-Optimal Second Order Discrete Control Systems, Chao-Tai Li

Masters Theses

"The time optimal control problem in unforced discrete systems is studied in this thesis. Comparison is made between the discrete and the continuous control systems by means of minimum time isochrones. concerning optimal time, it is shown that using the discrete control system will take at most one more sampling period of time to go to equilibrium. An investigation is also made for the case when the time constant of the physical plant, G(s), and the control model are different. In such a case, an optimal trajectory can not be obtained. An adaptive process is proposed to adjust the model …

Optimum Finite Memory Nonlinear Filter, Ching-Chyoun Yang

Masters Theses

"This thesis investigates the possibility of using the Zadah theory and a machine type computer to design an optimum finite memory nonlinear filter for extraction of Poisson distributed signal pulses from a background of Gaussian noise. Basically the procedure involves the technique of solving simultaneous equations by the computer. We demonstrate that it is possible to find the limitation of the filter of class N₁ in terms of an absolute minimum mean square error. However, due to the capacity of the computer we do not actually determine the absolute minimum. Nevertheless we do show that the mean square error decreases …

Stability Determination By Liapunov's Method In Nonlinear Control Systems, Neng-Chung Liao

Masters Theses

"An introduction to Liapunov's second method as it applies to control system stability is presented in this work. Main theorems and definitions of Liapunov's method are treated. In particular, Lur'e's method and Szego's method for testing the stability of a nonlinear system are presented, and several examples are used to illustrate these procedures"--Abstract, page ii.

Analog Computer Study Of Unequally Spaced Antenna Arrays, Fred M. Dickey

Masters Theses

"The problem undertaken in this thesis was to study the basic properties of unequally spaced antenna arrays. The study was done on a trial and error basis by simulating the expression for the far field pattern of a general array on an analog computer. Many patterns were obtained from the analog computer for the purpose of comparison. The patterns of two spacing schemes that are typical of unequally spaced arrays are presented for the purpose of illustration"--Abstract, page ii.

Linvill's Model As Applied To P-N Junction Photo-Diodes, Rudy Michael Chittenden

Masters Theses

"The problem undertaken in this study is to present a performance evaluation of Linvill's model as it pertains to the p-n junction photo-diode. The evaluation is performed by comparing the distributed mathematical solutions, the solution obtained using Linvill's lumped model, and the experimental measurement of the transient voltage rise across a photo-diode due to a unit-step pulse of light incident on the junction. Despite the absence of a suitable light source for use in the experimental measurement, it is concluded that Linvill's model provides an excellent means to determine the risetime of a photo-diode. This is provided that the photo-diode …

A Computer Approach To Transistor Circuit Design, Kwok Chee Hong

Masters Theses

"The design of amplifiers is usually approached through experimental study. This thesis proposes a mathematical approach, using a digital computer to predict the performance of an active transistor circuit (a frequency equalizer circuit to compensate for the RIAA recording frequency characteristics) prior to the actual construction of the physical system. The simple but powerful computer analysis method will be based upon the nodal equations of the complete circuit. The primary aim is to design a circuit which would give a desired frequency-gain characteristic. The complete set of simultaneous complex nodal equations describing the circuit operation is then written. Based on …

Matching Of A Horn Antenna To Its Dense Surrounding Media By The Use Of Artificial Dielectric Methods, Paul Arthur Ray

Masters Theses

"The purpose of this thesis is to design an artificial dielectric slug to match a horn in a media such as water and to discuss a method of determining experimentally its dielectric properties. The design is based on known artificial dielectric methods. The method of determining the dielectric properties is by microwave waveguide reflection techniques. This thesis deals with the theoretical aspects and suggests an experimental method of determining the practicability of such a matching method"--Abstract, page ii.

Equivalent Circuit Of Unsymmetrical Inductance Diode Using Linvill Lumped Model, Donald Lawrence Willyard

Masters Theses

"Integrated circuit techniques and applications are rapidly changing the electronics industry. A problem common to both state-of-the-art approaches to integrated circuit fabrication is that of miniaturizing and integrating inductors. It is found that, for a certain range of injection current levels, certain unsymmetrically doped junction diodes have an inductive small-signal impedance. This thesis discusses the theory of inductance diodes and applies finite difference equations and the Linvill lumped model to the differential equations that describe their carrier flow processes. The static I-V characteristic and the small-signal equivalent circuit at high injection densities are derived. The elements (R,L,C) of this equivalent …

Design Of Non-Uniform Linear Antenna Arrays With Digitized Spacing And Amplitude Levels, Jack F. Morris

Masters Theses

"Recent developments in space exploration have shown a need for high resolution, high gain antennas. The introduction of non-uniform linear array theory has provided a means by which arrays may be designed to produce narrow main beams with fewer elements than required by uniform arrays. A general theory has not been developed, however, and the design engineer has been left with only trial-and-error methods with which to work. In this study a technique has been developed by which non-uniform antenna arrays may be synthesized to meet a given set of specifications with reasonable accuracy. The elements of the array are …

A Circularly Polarized Corner Reflector Antenna, Walter Ronald Koenig

Masters Theses

"Image theory is used to develop the far field and polarization equations for a ninety degree corner reflector antenna. These equations are in terms of spherical coordinates, the length of the dipole element, the distance of the dipole from the corner of the reflector, and the angle of tilt of the dipole element with the apex of the corner. The equations are simplified to give the far fields in the vertical and horizontal planes for the special case of a half-wavelength dipole. An expression to calculate the distance of the dipole from the corner necessary to give circular polarization broadside …

An Evaluation Of Demonstrations On Inductor Theory, Boyd Warner Wasson

Dissertations and Theses @ UNI

The writer sought an improved approach for teaching theory of electronics to high school students. This approach was intended to require less expense and time needed to provide classroom instruction on electrical theory.

The purpose of this study were to:

(1) Prepare a number of demonstrations to illustrate phenomena associated with coils or inductors and their use in practical electronics.

(2) Prepare equipment and gather parts needed to perform demonstrations. Ease of construction and economy were important considerations.

(3) Evaluate the effectiveness of the demonstrations on student comprehension and the ability to apply information taught.

Transient Gamma Radiation Effects On Resistors, Harold T. Cates

Electrical and Computer Engineering ETDs

If a resistor in a circuit is exposed to a transient gamma radiation pulse, the condition of the circuit will be modified by passing from its steady state condition before radiation to a state of excitation that will depend upon the intensity and duration of the radiation pulse. When the radiation pulse is over, the circuit will then relax to its previous condition of equilibrium within a characteristic time constant.

When energetic radiation, such as gamma radiation, charged particles, or neutrons, strikes matter, it causes several effects which alter the properties of the target material. Some of the effects that …

Antennas In Or At The Surface Of A Conducting Medium At Vlf, George R. Swain

Electrical and Computer Engineering ETDs

To meet the requirements of a number of military operations and to facilitate some types of geophysical exploration, it is necessary to communicate between points beneath or at the surface of the earth or of the ocean. This need has led to the investigation of antennas for use in or at the surface of conducting media. The purpose of this paper is to briefly survey the previous work on such antennas, to extend the concepts of effective length and other merit factors to antennas in or near a conducting medium, and to analyze the electrical behavior of the toroid and …

An Experimental Determination Of Ultrasonic Wave Velocities In Plastics As Functions Of Temperature, Ned D. Arnold

Electrical and Computer Engineering ETDs

This thesis reports the results of an experimental investigation into the effects of temperature on the velocity of ultrasonic longitudinal acoustic waves through various plastics.

The Driving-Point Impedance Of An Electrically Short Cylindrical Antenna In The Ionosphere, William E. Blair

Electrical and Computer Engineering ETDs

1.0 Since the advent of satellites, there has been con­siderable interest in both military and peacetime uses of satellites as research instruments, communication relays, and transportation vehicles. In most cases, it is necessary to communicate with the satellites for purposes of trans­mitting and receiving information.

A Method Of Process Identification Of Certain Linear Control Systems, Eugene A. Aronson

Electrical and Computer Engineering ETDs

No abstract provided.

A Study Of Electro-Magnetic Wave Propagation In Inhomogeneous Media, Thomas N. C. Wang

Electrical and Computer Engineering ETDs

The central problem of this work will be the development of several approximation methods and the application thereof to the solution of second order linear differential equations which arise in connection with the propagation of electromagnetic radiation in inhomogeneous media. Chapter I is an introduction to the problem. Maxwell’s equations are written down and it is assumed that both σ, the conductivity, and ɛ, the permittivity, are scalar functions or position. Often the above function characterizing some or the properties of matter vary in physical situations. For example, in waveguides, there may be inserted layers of dielectric material along the …

The Multi-Terminal Hall Generator, Sang S. Pak

Electrical and Computer Engineering ETDs

This thesis describes a study undertaken to maximize the Hall generator efficiency. A mathematical solution is obtained for a multi-terminal Hall generator, and an analytical technique is developed for determining the optimum values of parameters to maximize the generator efficiency. An equivalent circuit is developed for an N output-terminal Hall generator, and the efficiency expression is obtained as a function of sample dimension, conductivity and Hall coefficient of the material, and magnetic field strength. Some of the results have been checked experimentally with indium antimonide and fields up to 21.5 kilogauss. An efficiency of 40% was obtained experimentally for a …

A Kerr Cell System For Measuring The Amplitude Of High-Voltage Nonrecurring Pulses, Donald C. Wunsch

Electrical and Computer Engineering ETDs

There are at present several conventional techniques and systems to measure the peak amplitude of high-voltage pulses. Three of the prin­cipal techniques are:

1. Potential dividers in conjunction with some type of low-voltage recording system.

2. High-voltage oscilloscopes with low sensitivity.

3. Sphere gaps with predetermined breakover voltages.

Potential dividers of many types have been developed. These include resistive voltage dividers, capacitive voltage dividers, and combination resistive and capacitive dividers. The different designs have usually been developed to eliminate some error in measurement. Different types of resistive windings have been designed to minimize self-inductance. Shields have been designed to reduce …

Predicting Current Gain Degradation In Npn Silicon Transistors After Irradiation By High-Energy Neutrons, Jerry A. Hood

Electrical and Computer Engineering ETDs

The damage discussed in this report is permanent and remains after all transient ionization has decayed. The damage which predominantly affects the electrical characteristics of a transistor is the creation of "vacancies" and "interstitials" in the lattice structure. These defects are created when an atom is knocked from its position and leaves a vacancy in the lattice. The atom comes to rest in a position out of the lattice structure and is known as interstitial. These atoms are knocked from their positions by the irradiating neutrons or by an interstitial traveling through the crystal. These defects occur in localized clusters …