Ludvig Lorenz, Electromagnetism, and the Theory of Telephone Currents
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Transmission Fundamentals
Transmission Fundamentals 1. What is the opposition to the transfer of energy which is considered the dominant characteristic of a cable or circuit that emanates from its physical structure? a. Conductance b. Resistance c. Reactance d. Impedance 2. When load impedance equals to Zo of the line, it means that the load _____ all the power. a. reflects b. absorbs c. attenuates d. radiates 3. impedance matching ratio of a coax balun. a. 1:4 b. 4:1 c. 2:1 d. 3:2 4. Which stands for dB relative level? a. dBrn b. dBa c. dBr d. dBx 5. Standard test tone used for audio measurement. a. 800 Hz b. 300 Hz c. 100 Hz d. 1000 Hz 6. When VSWR is equal to zero, this means a. that no power is applied b. that the load is purely resistive c. that the load is a pure reactance d. that the load is opened 7. _______ is the ratio of reflected voltage to the forward travelling voltage. a. SWR b. VSWR c. Reflection coefficient d. ISWR 8. Transmission line must be matched to the load to ______. a. transfer maximum voltage to the load b. transfer maximum power to the load c. reduce the load current d. transfer maximum current to the load 9. Which indicate the relative energy loss in a capacitor? a. Quality factor b. Reactive factor c. Dissipation factor d. Power factor 10. What is the standard test tone? a. 0 dB b. 0 dBW c. 0 dBm d. 0 dBrn 11. The energy that neither radiated into space nor completely transmitted. -
The Optical Thin-Film Model: Part 2
qM qMqM Previous Page | Contents |Zoom in | Zoom out | Front Cover | Search Issue | Next Page qMqM Qmags THE WORLD’S NEWSSTAND® The Optical Thin-Film Model: Part 2 Angus Macleod Thin Film Center, Inc., Tucson, AZ Contributed Original Article n part 1 of this account [1] we covered the early attempts to topics but for our present account it is his assembly of electricity Iunderstand the phenomenon of light but heavily weighted and magnetism into a coherent connected theory culminating in towards the optics of thin ilms. Acceptance of the wave theory the prediction of a wave combining electric and magnetic ields and followed the great contributions of Young and Fresnel. We found traveling at the speed of light that most interests us. an almost completely modern account of the fundamentals of Maxwell’s ideas of electromagnetism were much inluenced by optics in Airy’s Mathematical Tracts but omitting any ideas of Michael Faraday (1791-1867). Faraday was born in the south of absorption loss. hus, by the 1830’s multiple beam interference in England to a family with few resources and was essentially self single ilms was well organized with expressions that could be used educated. His apprenticeship with a local bookbinder allowed for accurate calculation in dielectrics. Lacking in all this, however, him access to books and he read voraciously and developed an was an appreciation of the real nature of the light wave. At this interest in science, nourished by his attendance at lectures in the stage the models were mechanical with Fresnel’s ideas of an array Royal Institution of Great Britain. -
Transparent Conductive Oxides – Fundamentals and Applications Agenda
BuildMoNa Symposium 2019 Transparent Conductive Oxides – Fundamentals and Applications Monday, 23 September to Friday, 27 September 2019 Universität Leipzig, 04103 Leipzig, Linnéstr. 5, Lecture Hall for Theoretical Physics Agenda Monday, 23 September 2019 13:00 Prof. Dr. Marius Grundmann Universität Leipzig, Germany Opening 13:05 Dr. Debdeep Jena* Cornell University, USA Paul Drude Lecture I: The Drude Model Lives On: Its Simplicity and Hidden Powers 13:50 Prof. Vanya Darakchieva* Linköping University, Sweden Paul Drude Lecture II: Optical properties of the electron gas 14:35 Dr. Robert Karsthof University of Oslo, Norway Revisiting the electronic transport in doped nickel oxide *Invited talk 1 14:50 Dr. Petr Novák University of West Bohemia, Plzeň, Czech Republic Important factors influencing the electrical properties of sputtered AZO thin films 15:05 Coffee break (Aula) 15:35 Dr. Andriy Zakutayev* National Renewable Energy Laboratory, USA Wide Band Gap Chalcogenide Semiconductors 16:20 Alexander Koch Universität Jena, Germany Ion Beam Doped Transparent Conductive Oxides for Metasurfaces 16:35 Prof. Chris van de Walle* UC Santa Barbara, USA Fundamental limits on transparency of transparent conducting oxides *Invited talk 2 Tuesday, 24 September 2019 08:15 Excursion BMW Group Plant Leipzig Departure by bus from Leipzig, Linnéstr. 5 09:15 Start Excursion BMW Visitor Center 12:15 Departure by bus from BMW Visitor Center 12:45 Lunch (Aula) 14:30 Prof. Dr. Pedro Barquinha* Universidade Nova de Lisboa, Portugal Towards autonomous flexible electronic systems with zinc-tin oxide thin films and nanostructures 15:15 Dr. Saud Bin Anooz Leibniz Institute for Crystal Growth, Berlin, Germany Optimization of β-Ga2O3 film growth on miscut (100) β-Ga2O3 substrates by MOVPE 15:30 Dr. -
3 the Invention of the Concertina
3 The Invention of the Concertina Introduction Having outlined the concertina’s place within the broad history of modern free-reed instruments, I now discuss in detail the circumstances surrounding its appearance and first commercial production. I seek to identify the intentions of its creator, the influences upon its form and the degree of innovation involved. In doing so I hope to address two popular, yet contrasting, views on the invention of the concertina. Firstly, I wish to challenge the view commonly held by enthusiasts of the instrument, including many of my informants, that its invention was the one-off, brilliant creation of an eccentric scientific genius. The concertina was first produced some time during the 1830s by Wheatstone and Co. of London and it is clear that its conception and design were the responsibility of Charles Wheatstone. It is, however, too easy to apply a “heroic” view of invention which clouds proper understanding of innovation in the nineteenth century and over-elevates individual achievements. As the previous chapter described, the concertina was just one of a number of new free-reed products to emerge from an extended period of research and innovation in musical instrument design and manufacture. I wish to emphasise here that it was also just one part of a line of innovations by its creator, who was also an outstanding teacher, experimenter and pioneering inventor in acoustics, optics, electricity, telegraphy and other fields. Secondly, while popular tradition privileges this single aspect of Wheatstone’s work, writers on scientific matters have tended to regard his activities in the musical field as an interesting sideline, engaged in while bearing early responsibility for the family music business but abandoned on maturity for pressing work in other, more important fields. -
Simple Circuit Theory and the Solution of Two Electricity Problems from The
Simple circuit theory and the solution of two electricity problems from the Victorian Age A C Tort ∗ Departamento de F´ısica Te´orica - Instituto de F´ısica Universidade Federal do Rio de Janeiro Caixa Postal 68.528; CEP 21941-972 Rio de Janeiro, Brazil May 22, 2018 Abstract Two problems from the Victorian Age, the subdivision of light and the determination of the leakage point in an undersea telegraphic cable are discussed and suggested as a concrete illustrations of the relationships between textbook physics and the real world. Ohm’s law and simple algebra are the only tools we need to discuss them in the classroom. arXiv:0811.0954v1 [physics.pop-ph] 6 Nov 2008 ∗e-mail: [email protected]. 1 1 Introduction Some time ago, the present author had the opportunity of reading Paul J. Nahin’s [1] fascinating biog- raphy of the Victorian physicist and electrician Oliver Heaviside (1850-1925). Heaviside’s scientific life unrolls against a background of theoretical and technical challenges that the scientific and technological developments fostered by the Industrial Revolution presented to engineers and physicists of those times. It is a time where electromagnetic theory as formulated by James Clerk Maxwell (1831-1879) was un- derstood by only a small group of men, Lodge, FitzGerald and Heaviside, among others, that had the mathematical sophistication and imagination to grasp the meaning and take part in the great Maxwellian synthesis. Almost all of the electrical engineers, or electricians as they were called at the time, considered themselves as “practical men”, which effectively meant that most of them had a working knowledge of the electromagnetic phenomena spiced up with bits of electrical theory, to wit, Ohm’s law and the Joule effect. -
The Concept of Field in the History of Electromagnetism
The concept of field in the history of electromagnetism Giovanni Miano Department of Electrical Engineering University of Naples Federico II ET2011-XXVII Riunione Annuale dei Ricercatori di Elettrotecnica Bologna 16-17 giugno 2011 Celebration of the 150th Birthday of Maxwell’s Equations 150 years ago (on March 1861) a young Maxwell (30 years old) published the first part of the paper On physical lines of force in which he wrote down the equations that, by bringing together the physics of electricity and magnetism, laid the foundations for electromagnetism and modern physics. Statue of Maxwell with its dog Toby. Plaque on E-side of the statue. Edinburgh, George Street. Talk Outline ! A brief survey of the birth of the electromagnetism: a long and intriguing story ! A rapid comparison of Weber’s electrodynamics and Maxwell’s theory: “direct action at distance” and “field theory” General References E. T. Wittaker, Theories of Aether and Electricity, Longam, Green and Co., London, 1910. O. Darrigol, Electrodynamics from Ampère to Einste in, Oxford University Press, 2000. O. M. Bucci, The Genesis of Maxwell’s Equations, in “History of Wireless”, T. K. Sarkar et al. Eds., Wiley-Interscience, 2006. Magnetism and Electricity In 1600 Gilbert published the “De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure” (On the Magnet and Magnetic Bodies, and on That Great Magnet the Earth). ! The Earth is magnetic ()*+(,-.*, Magnesia ad Sipylum) and this is why a compass points north. ! In a quite large class of bodies (glass, sulphur, …) the friction induces the same effect observed in the amber (!"#$%&'(, Elektron). Gilbert gave to it the name “electricus”. -
44 Transmission Lines
44 Transmission lines At the end of this chapter you should be able to: ž appreciate the purpose of a transmission line ž define the transmission line primary constants R, L, C and G ž calculate phase delay, wavelength and velocity of propagation on a transmission line ž appreciate current and voltage relationships on a transmission line ž define the transmission line secondary line constants Z0, , ˛ and ˇ ž calculate characteristic impedance and propagation coefficient in terms of the primary line constants ž understand and calculate distortion on transmission lines ž understand wave reflection and calculate reflection coefficient ž understand standing waves and calculate standing wave ratio 44.1 Introduction A transmission line is a system of conductors connecting one point to another and along which electromagnetic energy can be sent. Thus telephone lines and power distribution lines are typical examples of transmission lines; in electronics, however, the term usually implies a line used for the transmission of radio-frequency (r.f.) energy such as that from a radio transmitter to the antenna. An important feature of a transmission line is that it should guide energy from a source at the sending end to a load at the receiving end without loss by radiation. One form of construction often used consists of two similar conductors mounted close together at a constant separation. The two conductors form the two sides of a balanced circuit and any radiation from one of them is neutralized by that from the other. Such twin-wire lines are used for carrying high r.f. power, for example, at transmitters. -
530 Book Reviews
530 Book reviews found in the progressive stages of certainty brought about by systematic actions over nature rather than passive contemplation; authorization was the basic role of the House of Solomon, later to be materialized in the Royal Society; confirmation is related to all the personal virtues of the natural phil- osopher as prophet and gentleman (patience, self-sacrifice, constancy etc.); divination is identified with the inductive method; and prophecy appears in the supposedly plain style of reporting which included genres such as fables and aphorisms for the outsider in order to generate more debate. In Chapter 4 the book delves into the analogy between the prophetic temples as loci outside the polis and the Royal Society as a supposedly neutral environment in the political unrest of seventeenth-century England. After an interlude in which the author establishes an important distinction between the expert (who offers knowledge as if attainable by the majority) and the prophet (who presents knowledge as beyond the reach of the general public), the second part of the book takes us to America in the second half of the twentieth century. J. Robert Oppenheimer’s self-portrayal before, during and after his trial and Rachel Carson’s use of mass media are the two main examples Walsh presents of modern individual prophets: the former as a cultic prophet, an apostle for peace and a victim of political fear; the latter as an average housewife on the peripheries of academic science and political decisions creating a kairos for public debate on pesticides. More difficult to follow is the argument of Chapter 9 on the rhetorical technologies of climate change, where advocates and deniers of the importance of climate change seem to replicate prophetic patterns such as the accusation of bias in the opponents’ reports or the mixture of present description and future predictions. -
Wissenschaftlich-Philosophische Weltauffassung (Frankfurt Am Main
Contributors Fabio Bevilacqua is Associate Professor of the History of Physics in the Department of Physics "A. Volta" at the University of Pavia. He has published articles on the history of nineteenth-century physics and on the use of the history of science in science education, as well as a book entitled The Principle of Conservation of Energy and the History of Classical Electromagnetic Theory (Pavia: LaGoliardica Pavese, 1983). Giinter Bierhalter, an independent scholar living in Pfonheim, in the Federal Republic of Germany, is the author of articles on nine- teenth-century thermodynamics, including attempts to establish the mechanical foundations of thermodynamics and the problem of ir- reversibility. His principal scholarly interests are the history of the foundations of mechanics, extremum principles in physics, thermo- dynamics, and quantum physics. He is currently working on the history of nineteenth-century electrodynamics. Jed 2. Buchwald is Bern Dibner Professor of the History of Science at the Massachusetts Institute of Technology and Director of the Dib- ner Institute for the History of Science and Technology. In addition to numerous articles on the history of nineteenth-century electro- magnetism and optics, he is also the author of two book-length studies: From Maxwell to Microphysics. Aspects of Electromagnetic Theory in the Last Quarter of the Nineteenth Century (Chicago and London: The University of Chicago Press, 1985), and The Rise of the Wave Theory xvi Contributors of Light. Optical Theory and Experiment in the Early Nineteenth Cen- tury (Chicago and London: The University of Chicago Press, 1989). He has recently completed a book entitled The Creation of Scientijic Efects: Heinrich Hertz and Electric Waves (forthcoming). -
HISTORICAL SURVEY SOME PIONEERS of the APPLICATIONS of FRACTIONAL CALCULUS Duarte Valério 1, José Tenreiro Machado 2, Virginia
HISTORICAL SURVEY SOME PIONEERS OF THE APPLICATIONS OF FRACTIONAL CALCULUS Duarte Val´erio 1,Jos´e Tenreiro Machado 2, Virginia Kiryakova 3 Abstract In the last decades fractional calculus (FC) became an area of intensive research and development. This paper goes back and recalls important pio- neers that started to apply FC to scientific and engineering problems during the nineteenth and twentieth centuries. Those we present are, in alphabet- ical order: Niels Abel, Kenneth and Robert Cole, Andrew Gemant, Andrey N. Gerasimov, Oliver Heaviside, Paul L´evy, Rashid Sh. Nigmatullin, Yuri N. Rabotnov, George Scott Blair. MSC 2010 : Primary 26A33; Secondary 01A55, 01A60, 34A08 Key Words and Phrases: fractional calculus, applications, pioneers, Abel, Cole, Gemant, Gerasimov, Heaviside, L´evy, Nigmatullin, Rabotnov, Scott Blair 1. Introduction In 1695 Gottfried Leibniz asked Guillaume l’Hˆopital if the (integer) order of derivatives and integrals could be extended. Was it possible if the order was some irrational, fractional or complex number? “Dream commands life” and this idea motivated many mathematicians, physicists and engineers to develop the concept of fractional calculus (FC). Dur- ing four centuries many famous mathematicians contributed to the theo- retical development of FC. We can list (in alphabetical order) some im- portant researchers since 1695 (see details at [1, 2, 3], and posters at http://www.math.bas.bg/∼fcaa): c 2014 Diogenes Co., Sofia pp. 552–578 , DOI: 10.2478/s13540-014-0185-1 SOME PIONEERS OF THE APPLICATIONS . 553 • Abel, Niels Henrik (5 August 1802 - 6 April 1829), Norwegian math- ematician • Al-Bassam, M. A. (20th century), mathematician of Iraqi origin • Cole, Kenneth (1900 - 1984) and Robert (1914 - 1990), American physicists • Cossar, James (d. -
Lecture 2 - Transmission Line Theory Microwave Active Circuit Analysis and Design
Lecture 2 - Transmission Line Theory Microwave Active Circuit Analysis and Design Clive Poole and Izzat Darwazeh Academic Press Inc. © Poole-Darwazeh 2015 Lecture 2 - Transmission Line Theory Slide1 of 54 Intended Learning Outcomes I Knowledge I Understand that electrical energy travels at a finite speed in any medium, and the implications of this. I Understand the behaviour of lossy versus lossless transmission lines. I Understand power flows on a transmission line and the effect of discontinuities. I Skills I Be able to determine the location of a discontinuity in a transmission line using time domain refractometry. I Be able to apply the telegrapher’s equations in a design context. I Be able to calculate the reflection coefficient, standing wave ratio of a transmission line of known characteristic impedance with an arbitrary load. I Be able to calculate the input impedance of a transmission line of arbitrary physical length, and terminating impedance. I Be able to determine the impedance of a load given only the voltage standing wave ratio and the location of voltage maxima and minima on a line. © Poole-Darwazeh 2015 Lecture 2 - Transmission Line Theory Slide2 of 54 Table of Contents Propagation and reflection on a transmission line Sinusoidal steady state conditions : standing waves Primary line constants Derivation of the Characteristic Impedance Transmission lines with arbitrary terminations The effect of line losses Power Considerations © Poole-Darwazeh 2015 Lecture 2 - Transmission Line Theory Slide3 of 54 Propagation and reflection on a transmission line Let us consider a simple lossless transmission line, which could be simply a pair of parallel wires, terminated in a resistive load and connected to a DC source, such as a battery having a finite internal resistance, RS. -
A Solution of the Interpretation Problem of Lorentz Transformations
Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 30 July 2020 doi:10.20944/preprints202007.0705.v1 Article A Solution of the Interpretation Problem of Lorentz Transformations Grit Kalies* HTW University of Applied Sciences Dresden; 1 Friedrich-List-Platz, D-01069 Dresden, [email protected] * Correspondence: [email protected], Tel.: +49-351-462-2552 Abstract: For more than one hundred years, scientists dispute the correct interpretation of Lorentz transformations within the framework of the special theory of relativity of Albert Einstein. On the one hand, the changes in length, time and mass with increasing velocity are interpreted as apparent due to the observer dependence within special relativity. On the other hand, real changes are described corresponding to the experimental evidence of mass increase in particle accelerators or of clock delay. This ambiguity is accompanied by an ongoing controversy about valid Lorentz-transformed thermodynamic quantities such as entropy, pressure and temperature. In this paper is shown that the interpretation problem of the Lorentz transformations is genuinely anchored within the postulates of special relativity and can be solved on the basis of the thermodynamic approach of matter-energy equivalence, i.e. an energetic distinction between matter and mass. It is suggested that the velocity-dependent changes in state quantities are real in each case, in full agreement with the experimental evidence. Keywords: interpretation problem; Lorentz transformation; special relativity; thermodynamics; potential energy; space; time; entropy; non-mechanistic ether theory © 2020 by the author(s). Distributed under a Creative Commons CC BY license. Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 30 July 2020 doi:10.20944/preprints202007.0705.v1 2 of 25 1.