Electromagnetic Induction, Ac Circuits, and Electrical Technologies 813
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Electrostatics Voltage Source
012-07038B Instruction Sheet for the PASCO Model ES-9077 ELECTROSTATICS VOLTAGE SOURCE Specifications Ranges: • Fixed 1000, 2000, 3000 VDC ±10%, unregulated (maximum short circuit current less than 0.01 mA). • 30 VDC ±5%, 1mA max. Power: • 110-130 VDC, 60 Hz, ES-9077 • 220/240 VDC, 50 Hz, ES-9077-220 Dimensions: Introduction • 5 1/2” X 5” X 1”, plus AC adapter and red/black The ES-9077 is a high voltage, low current power cable set supply designed exclusively for experiments in electrostatics. It has outputs at 30 volts DC for IMPORTANT: To prevent the risk of capacitor plate experiments, and fixed 1 kV, 2 kV, and electric shock, do not remove the cover 3 kV outputs for Faraday ice pail and conducting on the unit. There are no user sphere experiments. With the exception of the 30 volt serviceable parts inside. Refer servicing output, all of the voltage outputs have a series to qualified service personnel. resistance associated with them which limit the available short-circuit output current to about 8.3 microamps. The 30 volt output is regulated but is Operation capable of delivering only about 1 milliamp before When using the Electrostatics Voltage Source to power falling out of regulation. other electric circuits, (like RC networks), use only the 30V output (Remember that the maximum drain is 1 Equipment Included: mA.). • Voltage Source Use the special high-voltage leads that are supplied with • Red/black, banana plug to spade lug cable the ES-9077 to make connections. Use of other leads • 9 VDC power supply may allow significant leakage from the leads to ground and negatively affect output voltage accuracy. -
Quantum Mechanics Electromotive Force
Quantum Mechanics_Electromotive force . Electromotive force, also called emf[1] (denoted and measured in volts), is the voltage developed by any source of electrical energy such as a batteryor dynamo.[2] The word "force" in this case is not used to mean mechanical force, measured in newtons, but a potential, or energy per unit of charge, measured involts. In electromagnetic induction, emf can be defined around a closed loop as the electromagnetic workthat would be transferred to a unit of charge if it travels once around that loop.[3] (While the charge travels around the loop, it can simultaneously lose the energy via resistance into thermal energy.) For a time-varying magnetic flux impinging a loop, theElectric potential scalar field is not defined due to circulating electric vector field, but nevertheless an emf does work that can be measured as a virtual electric potential around that loop.[4] In a two-terminal device (such as an electrochemical cell or electromagnetic generator), the emf can be measured as the open-circuit potential difference across the two terminals. The potential difference thus created drives current flow if an external circuit is attached to the source of emf. When current flows, however, the potential difference across the terminals is no longer equal to the emf, but will be smaller because of the voltage drop within the device due to its internal resistance. Devices that can provide emf includeelectrochemical cells, thermoelectric devices, solar cells and photodiodes, electrical generators,transformers, and even Van de Graaff generators.[4][5] In nature, emf is generated whenever magnetic field fluctuations occur through a surface. -
The Mathematical Modeling of Magnetostriction
THE MATHEMATICAL MODELING OF MAGNETOSTRICTION Katherine Shoemaker A Thesis Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of MASTERS OF ART May 2018 Committee: So-Hsiang Chou, Advisor Kit Chan Tong Sun c 2018 Katherine Shoemaker All rights reserved iii ABSTRACT So-Hsiang Chou, Advisor In this thesis, we study a system of differential equations that are used to model the material deformation due to magnetostriction both theoretically and numerically. The ordinary differential system is a mathematical model for a much more complex physical system established in labo- ratories. We are able to clarify that the phenomenon of double frequency is more delicate than originally suspected from pure physical considerations. It is shown that except for special cases, genuine double frequency does not arise. In particular, simulation results using the lab data is consistent with the experiment. iv I dedicate this work to my family. Even if they don’t understand it, they understand so much more. v ACKNOWLEDGMENTS I would like to express my sincerest gratitude to my advisor Dr. Chou. He has truly inspired me and made my graduate experience worthwhile. His guidance, both intellectually and spiritually, helped me through all the time spent researching and writing this thesis. I could not have asked for a better advisor, or a better instructor and I am truly appreciative of all the support he gave. In addition, I would like to thank the remaining faculty on my thesis committee: Dr. Tong Sun and Dr. Kit Chan, for supporting me through their instruction and mentorship. -
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. -
Calculating Electric Power
Calculating electric power We've seen the formula for determining the power in an electric circuit: by multiplying the voltage in "volts" by the current in "amps" we arrive at an answer in "watts." Let's apply this to a circuit example: In the above circuit, we know we have a battery voltage of 18 volts and a lamp resistance of 3 Ω. Using Ohm's Law to determine current, we get: Now that we know the current, we can take that value and multiply it by the voltage to determine power: Answer: the lamp is dissipating (releasing) 108 watts of power, most likely in the form of both light and heat. Let's try taking that same circuit and increasing the battery voltage to see what happens. Intuition should tell us that the circuit current will increase as the voltage increases and the lamp resistance stays the same. Likewise, the power will increase as well: Now, the battery voltage is 36 volts instead of 18 volts. The lamp is still providing 3 Ω of electrical resistance to the flow of electrons. The current is now: This stands to reason: if I = E/R, and we double E while R stays the same, the current should double. Indeed, it has: we now have 12 amps of current instead of 6. Now, what about power? Notice that the power has increased just as we might have suspected, but it increased quite a bit more than the current. Why is this? Because power is a function of voltage multiplied by current, and both voltage and current doubled from their previous values, the power will increase by a factor of 2 x 2, or 4. -
Electromotive Force
Voltage - Electromotive Force Electrical current flow is the movement of electrons through conductors. But why would the electrons want to move? Electrons move because they get pushed by some external force. There are several energy sources that can force electrons to move. Chemical: Battery Magnetic: Generator Light (Photons): Solar Cell Mechanical: Phonograph pickup, crystal microphone, antiknock sensor Heat: Thermocouple Voltage is the amount of push or pressure that is being applied to the electrons. It is analogous to water pressure. With higher water pressure, more water is forced through a pipe in a given time. With higher voltage, more electrons are pushed through a wire in a given time. If a hose is connected between two faucets with the same pressure, no water flows. For water to flow through the hose, it is necessary to have a difference in water pressure (measured in psi) between the two ends. In the same way, For electrical current to flow in a wire, it is necessary to have a difference in electrical potential (measured in volts) between the two ends of the wire. A battery is an energy source that provides an electrical difference of potential that is capable of forcing electrons through an electrical circuit. We can measure the potential between its two terminals with a voltmeter. Water Tank High Pressure _ e r u e s g s a e t r l Pump p o + v = = t h g i e h No Pressure Figure 1: A Voltage Source Water Analogy. In any case, electrostatic force actually moves the electrons. -
Magnetic Fields
Welcome Back to Physics 1308 Magnetic Fields Sir Joseph John Thomson 18 December 1856 – 30 August 1940 Physics 1308: General Physics II - Professor Jodi Cooley Announcements • Assignments for Tuesday, October 30th: - Reading: Chapter 29.1 - 29.3 - Watch Videos: - https://youtu.be/5Dyfr9QQOkE — Lecture 17 - The Biot-Savart Law - https://youtu.be/0hDdcXrrn94 — Lecture 17 - The Solenoid • Homework 9 Assigned - due before class on Tuesday, October 30th. Physics 1308: General Physics II - Professor Jodi Cooley Physics 1308: General Physics II - Professor Jodi Cooley Review Question 1 Consider the two rectangular areas shown with a point P located at the midpoint between the two areas. The rectangular area on the left contains a bar magnet with the south pole near point P. The rectangle on the right is initially empty. How will the magnetic field at P change, if at all, when a second bar magnet is placed on the right rectangle with its north pole near point P? A) The direction of the magnetic field will not change, but its magnitude will decrease. B) The direction of the magnetic field will not change, but its magnitude will increase. C) The magnetic field at P will be zero tesla. D) The direction of the magnetic field will change and its magnitude will increase. E) The direction of the magnetic field will change and its magnitude will decrease. Physics 1308: General Physics II - Professor Jodi Cooley Review Question 2 An electron traveling due east in a region that contains only a magnetic field experiences a vertically downward force, toward the surface of the earth. -
Non-Propellant Eddy Current Brake and Traction in Space Using Magnetic Pulses
aerospace Article Non-Propellant Eddy Current Brake and Traction in Space Using Magnetic Pulses Yi Zhang †, Qiang Shen †, Liqiang Hou † and Shufan Wu * School of Aeronautics and Astronautics, Shanghai Jiao Tong University, No. 800, Dongchuan Road, Minhang District, Shanghai 200240, China; [email protected] (Y.Z.); [email protected] (Q.S.); [email protected] (L.H.) * Correspondence: [email protected]; Tel.: +86-34208597 † These authors contributed equally to this work. Abstract: The safety of on-orbit satellites is threatened by space debris with large residual angular velocity and the space debris removal is becoming more challenging than before. This paper explores the non-contact despinning and traction problem of high-speed rotating targets and proposes an eddy current brake and traction technology for space targets without any propellant consumption. The principle of the conventional eddy current brake is analyzed in this article and the concept of eddy current brake and traction without propellant is put forward for the first time. Secondly, according to the key technical requirements, a brand-new structure of a satellite generating artificial magnetic field is designed accordingly. Then the control mechanism of eddy current brake and traction without propellant is analyzed qualitatively by simplifying the model and conditions. Then, the magnetic pulse control method is proposed and analyzed quantitatively. Finally, the feasibility of the technology is verified by the numerical simulation method. According to the simulation results, the eddy current brake and traction technology based on magnetic pulses can make the angular speed of target decrease linearly without propellant during the process. -
Lecture 30 Motional Emf
LECTURE 30 MOTIONAL EMF Instructor: Kazumi Tolich Lecture 30 2 ¨ Reading chapter 23-3 & 23-4. ¤ Motional emf ¤ Mechanical work and electrical energy Clicker question: 1 3 Motional emf 4 ¨ As the rod moves to the right at a constant velocity v, the motional emf is given by ΔΦ BΔA lvΔt E = N = = B = Bvl Δt Δt Δt Example: 1 5 ¨ A Boeing KC-135A airplane has a wingspan of L = 39.9 m and flies at constant altitude in a northerly direction with a speed of v = 240 m/s. If the vertical component of the Earth’s magnetic -6 field is Bv = 5.0 × 10 T, and its -6 horizontal component is Bh = 1.4 × 10 T, what is the induced emf between the wing tips? Clicker question: 2 & 3 6 Mechanical and electric powers 7 ¨ Suppose the rod is moving with a constant velocity �. ¨ The mechanical power delivered by the external force is: ¨ Compare this to the electrical power in the light bulb: ¨ Therefore, mechanical power has been converted directly into electrical power. Example: 2 8 ¨ In the figure, let the magnetic field strength be B = 0.80 T, the rod speed be v = 10 m/s, the rod length be l = 0.20 m, and the resistance of the resistor be R = 2.0 Ω. (The resistance of the rod and rails are negligible.) a) Find the induced emf in the circuit. b) Find the induced current in the circuit (including direction). c) Find the force needed to move the rod with constant speed (assuming negligible friction). -
Learn Why Eddy-Current Sensors Are Now Replacing Inductive Sensors and Switches
AP Corp | (508) 351-6200 | www.a-pcorp.com Learn Why Eddy-Current Sensors Are Now Replacing Inductive Sensors and Switches Both eddy-current sensors as well as inductive switches and displacement sensors have been used for many years, each having their respective advantages when it comes to measuring position and displacement of objects in harsh environments. However, recent advances in eddy-current sensor design, integration and packaging, as well as overall cost reduction, have made these sensors a much more attractive option. This is especially true where high linearity, high-speed measurements and high resolution are critical requirements. Common Inductive Sensors & Switches To appreciate the inherent advantages of eddy-current sensors, relative to inductive switches and displacement sensors, it’s important to first understand the principle of operation of both types. The classic inductive displacement sensor comprises a coil that is wound around a ferromagnetic core. When excited by an alternating current from an oscillator-based driver circuit, the coil generates a magnetic field that is concentrated around the core. The lines of flux interact with the target conductor as it approaches, creating eddy currents that are the reverse of the initial excitation current and have the effect of reducing the voltage across the oscillator. These variations in voltage due to the change in air gap distance are detected and converted to an analog output signal, such as a 4-20mA loop, and then processed upstream to determine displacement. 1 AP Corp | (508) 351-6200 | www.a-pcorp.com In an inductive displacement sensor, a coil is wrapped around a ferromagnetic core and when an alternating current is passed through the coil it generates a magnetic field. -
Transformed E&M I Homework Magnetic Vector Potential
Transformed E&M I homework Magnetic Vector Potential (Griffiths Chapter 5) Magnetic Vector Potential A Question 1. Vector potential inside current-carrying conductor Lorrain, Dorson, Lorrain, 15-1 pg. 272 Show that, inside a straight current-carrying conductor of radius R, µ Ι ρ 2 Α = 0 (1− ) 2π R 2 If A is set equal to zero at ρ = R. Question 2. Multipoles, dipole moment The vector potential of a small current loop (a magnetic dipole) with magnetic moment µ0 m × rˆ m is A = 2 4π r A) Assume that the magnetic dipole is at the origin and the magnetic moment is aligned with the +z axis. Use the vector potential to compute the B-field in spherical coordinates. B) Show that your expression for the B-field in part (a) can be written in the coordinate- € µ 1 0 ˆ ˆ free form B(r) = 3 3(m⋅r)r − m 4π r Note: The easiest way to do this one is by assuming the coordinate-free form and then showing that you get your expression in part (a) if you define your z axis to lie along m, rather than trying to go the other way around. Coordinate free formulas are nice, because now you can find B for more general situations. Question 3. Vector Potential of infinite sheet Lorrain, Dorson; Example, Pair of Long Parallel Currents pg. 252 Figure 14-10 shows two long parallel wires separated by a distance D and carrying equal currents I in opposite directions. To calculate A, we use the above result for the A of a single wire and add the two vector potentials: µ Ι L L A = 0 (ln − ln ) (14-37) 2π ρ a ρb Do Bx, By, and Bz at midpoint stretch? Question 4. -
Design and Optimization of Printed Circuit Board Inductors for Wireless Power Transfer System
University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Engineering -- Faculty Publications and Other Faculty Publications and Other Works -- EECS Works 4-2013 Design and Optimization of Printed Circuit Board Inductors for Wireless Power Transfer System Ashraf B. Islam University of Tennessee - Knoxville Syed K. Islam University of Tennessee - Knoxville Fahmida S. Tulip Follow this and additional works at: https://trace.tennessee.edu/utk_elecpubs Part of the Electrical and Computer Engineering Commons Recommended Citation Islam, Ashraf B.; Islam, Syed K.; and Tulip, Fahmida S., "Design and Optimization of Printed Circuit Board Inductors for Wireless Power Transfer System" (2013). Faculty Publications and Other Works -- EECS. https://trace.tennessee.edu/utk_elecpubs/21 This Article is brought to you for free and open access by the Engineering -- Faculty Publications and Other Works at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Faculty Publications and Other Works -- EECS by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. Circuits and Systems, 2013, 4, 237-244 http://dx.doi.org/10.4236/cs.2013.42032 Published Online April 2013 (http://www.scirp.org/journal/cs) Design and Optimization of Printed Circuit Board Inductors for Wireless Power Transfer System Ashraf B. Islam, Syed K. Islam, Fahmida S. Tulip Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, USA Email: [email protected] Received November 20, 2012; revised December 20, 2012; accepted December 27, 2012 Copyright © 2013 Ashraf B. Islam et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.