Basic Terms in Electrical Engineering
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Glossary Physics (I-Introduction)
1 Glossary Physics (I-introduction) - Efficiency: The percent of the work put into a machine that is converted into useful work output; = work done / energy used [-]. = eta In machines: The work output of any machine cannot exceed the work input (<=100%); in an ideal machine, where no energy is transformed into heat: work(input) = work(output), =100%. Energy: The property of a system that enables it to do work. Conservation o. E.: Energy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes. Equilibrium: The state of an object when not acted upon by a net force or net torque; an object in equilibrium may be at rest or moving at uniform velocity - not accelerating. Mechanical E.: The state of an object or system of objects for which any impressed forces cancels to zero and no acceleration occurs. Dynamic E.: Object is moving without experiencing acceleration. Static E.: Object is at rest.F Force: The influence that can cause an object to be accelerated or retarded; is always in the direction of the net force, hence a vector quantity; the four elementary forces are: Electromagnetic F.: Is an attraction or repulsion G, gravit. const.6.672E-11[Nm2/kg2] between electric charges: d, distance [m] 2 2 2 2 F = 1/(40) (q1q2/d ) [(CC/m )(Nm /C )] = [N] m,M, mass [kg] Gravitational F.: Is a mutual attraction between all masses: q, charge [As] [C] 2 2 2 2 F = GmM/d [Nm /kg kg 1/m ] = [N] 0, dielectric constant Strong F.: (nuclear force) Acts within the nuclei of atoms: 8.854E-12 [C2/Nm2] [F/m] 2 2 2 2 2 F = 1/(40) (e /d ) [(CC/m )(Nm /C )] = [N] , 3.14 [-] Weak F.: Manifests itself in special reactions among elementary e, 1.60210 E-19 [As] [C] particles, such as the reaction that occur in radioactive decay. -
EXPERIMENT 4: RC, RL and RD Circuits
Laboratory 4: The RC Circuit EXPERIMENT 4: RC, RL and RD CIRCUITs Equipment List An assortment of resistor, one each of (330, 1k,1.5k, 10k,100k,1000k) Function Generator Oscilloscope 0.F Ceramic Capacitor 100H Inductor LED and 1N4001 Diode. Introduction We have studied D.C. circuits with resistors and batteries and discovered that Ohm’s Law governs the relationship between current through and voltage across a resistance. It is a linear response; i.e., 푉 = 퐼푅 (1) Such circuit elements are called passive elements. With A.C. circuits we find other passive elements called capacitors and inductors. These, too, obey Ohm’s Law and circuit loop problems can be solved using Kirchoff’ 3 Laws in much the same way as with DC. circuits. However, there is one major difference - in an AC. circuit, voltage across and current through a circuit element or branch are not necessarily in phase with one another. We saw an example of this at the end of Experiment 3. In an AC. series circuit the source voltage and current are time dependent such that 푖(푡) = 푖푠sin(휔푡) (2) 푣(푡) = 푣푠sin(휔푡 + 휙) where, in this case, voltage leads current by the phase angle , and Vs and Is are the peak source voltage and peak current, respectively. As you know or will learn from the text, the phase relationships between circuit element voltages and series current are these: resistor - voltage and current are in phase implying that 휙 = 0 휋 capacitor - voltage lags current by 90o implying that 휙 = − 2 inductor - voltage leads current by 90o implying that 휙 = 휋/2 Laboratory 4: The RC Circuit In this experiment we will study a circuit with a resistor and a capacitor in m. -
Chapter 7: AC Transistor Amplifiers
Chapter 7: Transistors, part 2 Chapter 7: AC Transistor Amplifiers The transistor amplifiers that we studied in the last chapter have some serious problems for use in AC signals. Their most serious shortcoming is that there is a “dead region” where small signals do not turn on the transistor. So, if your signal is smaller than 0.6 V, or if it is negative, the transistor does not conduct and the amplifier does not work. Design goals for an AC amplifier Before moving on to making a better AC amplifier, let’s define some useful terms. We define the output range to be the range of possible output voltages. We refer to the maximum and minimum output voltages as the rail voltages and the output swing is the difference between the rail voltages. The input range is the range of input voltages that produce outputs which are not at either rail voltage. Our goal in designing an AC amplifier is to get an input range and output range which is symmetric around zero and ensure that there is not a dead region. To do this we need make sure that the transistor is in conduction for all of our input range. How does this work? We do it by adding an offset voltage to the input to make sure the voltage presented to the transistor’s base with no input signal, the resting or quiescent voltage , is well above ground. In lab 6, the function generator provided the offset, in this chapter we will show how to design an amplifier which provides its own offset. -
Unit-1 Mphycc-7 Ujt
UNIT-1 MPHYCC-7 UJT The Unijunction Transistor or UJT for short, is another solid state three terminal device that can be used in gate pulse, timing circuits and trigger generator applications to switch and control either thyristors and triac’s for AC power control type applications. Like diodes, unijunction transistors are constructed from separate P-type and N-type semiconductor materials forming a single (hence its name Uni-Junction) PN-junction within the main conducting N-type channel of the device. Although the Unijunction Transistor has the name of a transistor, its switching characteristics are very different from those of a conventional bipolar or field effect transistor as it can not be used to amplify a signal but instead is used as a ON-OFF switching transistor. UJT’s have unidirectional conductivity and negative impedance characteristics acting more like a variable voltage divider during breakdown. Like N-channel FET’s, the UJT consists of a single solid piece of N-type semiconductor material forming the main current carrying channel with its two outer connections marked as Base 2 ( B2 ) and Base 1 ( B1 ). The third connection, confusingly marked as the Emitter ( E ) is located along the channel. The emitter terminal is represented by an arrow pointing from the P-type emitter to the N-type base. The Emitter rectifying p-n junction of the unijunction transistor is formed by fusing the P-type material into the N-type silicon channel. However, P-channel UJT’s with an N- type Emitter terminal are also available but these are little used. -
Electromagnetism What Is the Effect of the Number of Windings of Wire on the Strength of an Electromagnet?
TEACHER’S GUIDE Electromagnetism What is the effect of the number of windings of wire on the strength of an electromagnet? GRADES 6–8 Physical Science INQUIRY-BASED Science Electromagnetism Physical Grade Level/ 6–8/Physical Science Content Lesson Summary In this lesson students learn how to make an electromagnet out of a battery, nail, and wire. The students explore and then explain how the number of turns of wire affects the strength of an electromagnet. Estimated Time 2, 45-minute class periods Materials D cell batteries, common nails (20D), speaker wire (18 gauge), compass, package of wire brad nails (1.0 mm x 12.7 mm or similar size), Investigation Plan, journal Secondary How Stuff Works: How Electromagnets Work Resources Jefferson Lab: What is an electromagnet? YouTube: Electromagnet - Explained YouTube: Electromagnets - How can electricity create a magnet? NGSS Connection MS-PS2-3 Ask questions about data to determine the factors that affect the strength of electric and magnetic forces. Learning Objectives • Students will frame a hypothesis to predict the strength of an electromagnet due to changes in the number of windings. • Students will collect and analyze data to determine how the number of windings affects the strength of an electromagnet. What is the effect of the number of windings of wire on the strength of an electromagnet? Electromagnetism is one of the four fundamental forces of the universe that we rely on in many ways throughout our day. Most home appliances contain electromagnets that power motors. Particle accelerators, like CERN’s Large Hadron Collider, use electromagnets to control the speed and direction of these speedy particles. -
Electromagnetism
EINE INITIATIVE DER UNIVERSITÄT BASEL UND DES KANTONS AARGAU Swiss Nanoscience Institute Electromagnetism Electricity and magnetism are two aspects of the same phenomenon: electromagnetism. A moving electric charge (in other words, an electric current) generates a magnetic field. Every electromagnet consists of a coil, which is nothing more than a tightly wound wire. Many electromagnets also have an iron core to make the magnetic field stronger. The more times the wire is wound around the coil, the stronger the magnetic field produced by the same current. Demonstration: Using electric current to create a magnetic field What you’ll need • a large sheet of paper on which to conduct the experiment • a sheet of stiff card or plexiglass • two batteries connected in series • a coil of copper wire • iron filings • crocodile clips (optional) • a small piece of iron (e.g. a screw) to place inside the coil (iron core) Instructions 1. Position the coil so that you can easily access the two ends of the wire and connect them to the battery. I used crocodile clips to attach them to the battery contacts, but you could also use wooden clothes pegs or electrical tape. 2. Connect the two batteries in series (+ - + - ). 3. Place the plexiglass or card over the coil. 4. When the electrical circuit is closed, slowly scatter the iron filings on top. What happens? The iron filings arrange themselves along the magnetic field lines. If you look closely, you can make out a pattern. Turn a screw into an electromagnet What you’ll need • a long iron screw or nail • two pieces of insulated copper wire measuring 15 and 30 cm • two three-pronged thumb tacks • a metal paperclip • a small wooden board • pins or paperclips • a 4.5 V battery Instructions Switch 1. -
Measuring Electricity Voltage Current Voltage Current
Measuring Electricity Electricity makes our lives easier, but it can seem like a mysterious force. Measuring electricity is confusing because we cannot see it. We are familiar with terms such as watt, volt, and amp, but we do not have a clear understanding of these terms. We buy a 60-watt lightbulb, a tool that needs 120 volts, or a vacuum cleaner that uses 8.8 amps, and dont think about what those units mean. Using the flow of water as an analogy can make Voltage electricity easier to understand. The flow of electrons in a circuit is similar to water flowing through a hose. If you could look into a hose at a given point, you would see a certain amount of water passing that point each second. The amount of water depends on how much pressure is being applied how hard the water is being pushed. It also depends on the diameter of the hose. The harder the pressure and the larger the diameter of the hose, the more water passes each second. The flow of electrons through a wire depends on the electrical pressure pushing the electrons and on the Current cross-sectional area of the wire. The flow of electrons can be compared to the flow of Voltage water. The water current is the number of molecules flowing past a fixed point; electrical current is the The pressure that pushes electrons in a circuit is number of electrons flowing past a fixed point. called voltage. Using the water analogy, if a tank of Electrical current (I) is defined as electrons flowing water were suspended one meter above the ground between two points having a difference in voltage. -
On the Nature of Electric Charge
Vol. 9(4), pp. 54-60, 28 February, 2014 DOI: 10.5897/IJPS2013.4091 ISSN 1992 - 1950 International Journal of Physical Copyright © 2014 Author(s) retain the copyright of this article Sciences http://www.academicjournals.org/IJPS Full Length Research Paper On the nature of electric charge Jafari Najafi, Mahdi 1730 N Lynn ST apt A35, Arlington, VA 22209 USA. Received 10 December, 2013; Accepted 14 February, 2014 A few hundred years have passed since the discovery of electricity and electromagnetic fields, formulating them as Maxwell's equations, but the nature of an electric charge remains unknown. Why do particles with the same charge repel and opposing charges attract? Is the electric charge a primary intrinsic property of a particle? These questions cannot be answered until the nature of the electric charge is identified. The present study provides an explicit description of the gravitational constant G and the origin of electric charge will be inferred using generalized dimensional analysis. Key words: Electric charge, gravitational constant, dimensional analysis, particle mass change. INTRODUCTION The universe is composed of three basic elements; parameters. This approach is of great generality and mass-energy (M), length (L), and time (T). Intrinsic mathematical simplicity that simply and directly properties are assigned to particles, including mass, postulates a hypothesis for the nature of the electric electric charge, and spin, and their effects are applied in charge. Although the final formula is a guesswork based the form of physical formulas that explicitly address on dimensional analysis of electric charges, it shows the physical phenomena. The meaning of some particle existence of consistency between the final formula and properties remains opaque. -
1.3.4 Atoms and Molecules Name Symbol Definition SI Unit
1.3.4 Atoms and molecules Name Symbol Definition SI unit Notes nucleon number, A 1 mass number proton number, Z 1 atomic number neutron number N N = A - Z 1 electron rest mass me kg (1) mass of atom, ma, m kg atomic mass 12 atomic mass constant mu mu = ma( C)/12 kg (1), (2) mass excess ∆ ∆ = ma - Amu kg elementary charge, e C proton charage Planck constant h J s Planck constant/2π h h = h/2π J s 2 2 Bohr radius a0 a0 = 4πε0 h /mee m -1 Rydberg constant R∞ R∞ = Eh/2hc m 2 fine structure constant α α = e /4πε0 h c 1 ionization energy Ei J electron affinity Eea J (1) Analogous symbols are used for other particles with subscripts: p for proton, n for neutron, a for atom, N for nucleus, etc. (2) mu is equal to the unified atomic mass unit, with symbol u, i.e. mu = 1 u. In biochemistry the name dalton, with symbol Da, is used for the unified atomic mass unit, although the name and symbols have not been accepted by CGPM. Chapter 1 - 1 Name Symbol Definition SI unit Notes electronegativity χ χ = ½(Ei +Eea) J (3) dissociation energy Ed, D J from the ground state D0 J (4) from the potential De J (4) minimum principal quantum n E = -hcR/n2 1 number (H atom) angular momentum see under Spectroscopy, section 3.5. quantum numbers -1 magnetic dipole m, µ Ep = -m⋅⋅⋅B J T (5) moment of a molecule magnetizability ξ m = ξB J T-2 of a molecule -1 Bohr magneton µB µB = eh/2me J T (3) The concept of electronegativity was intoduced by L. -
Guide for the Use of the International System of Units (SI)
Guide for the Use of the International System of Units (SI) m kg s cd SI mol K A NIST Special Publication 811 2008 Edition Ambler Thompson and Barry N. Taylor NIST Special Publication 811 2008 Edition Guide for the Use of the International System of Units (SI) Ambler Thompson Technology Services and Barry N. Taylor Physics Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899 (Supersedes NIST Special Publication 811, 1995 Edition, April 1995) March 2008 U.S. Department of Commerce Carlos M. Gutierrez, Secretary National Institute of Standards and Technology James M. Turner, Acting Director National Institute of Standards and Technology Special Publication 811, 2008 Edition (Supersedes NIST Special Publication 811, April 1995 Edition) Natl. Inst. Stand. Technol. Spec. Publ. 811, 2008 Ed., 85 pages (March 2008; 2nd printing November 2008) CODEN: NSPUE3 Note on 2nd printing: This 2nd printing dated November 2008 of NIST SP811 corrects a number of minor typographical errors present in the 1st printing dated March 2008. Guide for the Use of the International System of Units (SI) Preface The International System of Units, universally abbreviated SI (from the French Le Système International d’Unités), is the modern metric system of measurement. Long the dominant measurement system used in science, the SI is becoming the dominant measurement system used in international commerce. The Omnibus Trade and Competitiveness Act of August 1988 [Public Law (PL) 100-418] changed the name of the National Bureau of Standards (NBS) to the National Institute of Standards and Technology (NIST) and gave to NIST the added task of helping U.S. -
Music Synthesis
MUSIC SYNTHESIS Sound synthesis is the art of using electronic devices to create & modify signals that are then turned into sound waves by a speaker. Making Waves: WGRL - 2015 Oscillators An oscillator generates a consistent, repeating signal. Signals from oscillators and other sources are used to control the movement of the cones in our speakers, which make real sound waves which travel to our ears. An oscillator wiggles an audio signal. DEMONSTRATE: If you tie one end of a rope to a doorknob, stand back a few feet, and wiggle the other end of the rope up and down really fast, you're doing roughly the same thing as an oscillator. REVIEW: Frequency and pitch Frequency, measured in cycles/second AKA Hertz, is the rate at which a sound wave moves in and out. The length of a signal cycle of a waveform is the span of time it takes for that waveform to repeat. People generally hear an increase in the frequency of a sound wave as an increase in pitch. F DEMONSTRATE: an oscillator generating a signal that repeats at the rate of 440 cycles per second will have the same pitch as middle A on a piano. An oscillator generating a signal that repeats at 880 cycles per second will have the same pitch as the A an octave above middle A. Types of Waveforms: SINE The SINE wave is the most basic, pure waveform. These simple waves have only one frequency. Any other waveform can be created by adding up a series of sine waves. In this picture, the first two sine waves In this picture, a sine wave is added to its are added together to produce a third. -
Modeling Optical Metamaterials with Strong Spatial Dispersion
Fakultät für Physik Institut für theoretische Festkörperphysik Modeling Optical Metamaterials with Strong Spatial Dispersion M. Sc. Karim Mnasri von der KIT-Fakultät für Physik des Karlsruher Instituts für Technologie (KIT) genehmigte Dissertation zur Erlangung des akademischen Grades eines DOKTORS DER NATURWISSENSCHAFTEN (Dr. rer. nat.) Tag der mündlichen Prüfung: 29. November 2019 Referent: Prof. Dr. Carsten Rockstuhl (Institut für theoretische Festkörperphysik) Korreferent: Prof. Dr. Michael Plum (Institut für Analysis) KIT – Die Forschungsuniversität in der Helmholtz-Gemeinschaft Erklärung zur Selbstständigkeit Ich versichere, dass ich diese Arbeit selbstständig verfasst habe und keine anderen als die angegebenen Quellen und Hilfsmittel benutzt habe, die wörtlich oder inhaltlich über- nommenen Stellen als solche kenntlich gemacht und die Satzung des KIT zur Sicherung guter wissenschaftlicher Praxis in der gültigen Fassung vom 24. Mai 2018 beachtet habe. Karlsruhe, den 21. Oktober 2019, Karim Mnasri Als Prüfungsexemplar genehmigt von Karlsruhe, den 28. Oktober 2019, Prof. Dr. Carsten Rockstuhl iv To Ouiem and Adam Thesis abstract Optical metamaterials are artificial media made from subwavelength inclusions with un- conventional properties at optical frequencies. While a response to the magnetic field of light in natural material is absent, metamaterials prompt to lift this limitation and to exhibit a response to both electric and magnetic fields at optical frequencies. Due tothe interplay of both the actual shape of the inclusions and the material from which they are made, but also from the specific details of their arrangement, the response canbe driven to one or multiple resonances within a desired frequency band. With such a high number of degrees of freedom, tedious trial-and-error simulations and costly experimen- tal essays are inefficient when considering optical metamaterials in the design of specific applications.