What is Electrical: Definition and 1000 Discussions

Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others.
The presence of an electric charge, which can be either positive or negative, produces an electric field. The movement of electric charges is an electric current and produces a magnetic field.
When a charge is placed in a location with a non-zero electric field, a force will act on it. The magnitude of this force is given by Coulomb's law. If the charge moves, the electric field would be doing work on the electric charge. Thus we can speak of electric potential at a certain point in space, which is equal to the work done by an external agent in carrying a unit of positive charge from an arbitrarily chosen reference point to that point without any acceleration and is typically measured in volts.
Electricity is at the heart of many modern technologies, being used for:

Electric power where electric current is used to energise equipment;
Electronics which deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies.Electrical phenomena have been studied since antiquity, though progress in theoretical understanding remained slow until the seventeenth and eighteenth centuries. The theory of electromagnetism was developed in the 19th century, and by the end of that century electricity was being put to industrial and residential use by electrical engineers. The rapid expansion in electrical technology at this time transformed industry and society, becoming a driving force for the Second Industrial Revolution. Electricity's extraordinary versatility means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. Electrical power is now the backbone of modern industrial society.

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  1. M

    Calculate the temperature of a wire as an electrical current flows through it

    Hey, so I'm just wondering what are the formulas needed to calculate the temperature of a wire after x amount of time as an electrical current is passed through it. I know how to solve for it... I just forgot the formulas. Thanks
  2. louisnach

    Electrical Engineering, power system, transmission line

    Homework Statement A 400 kV transmission line has a length of 500 km and a reactance of 0,4 Ω/km. How much power can you transmit, if the power angle (the angle between the voltages of the beginning and the end) is limited to 25 degrees? What would then be the line’s boundary power limit for...
  3. D

    Electrical and Mechanical Energy as it relates to Capacitors

    Homework Statement In my lab, we are studying the efficiency of a simple DC motor. In order to do this, we related the initial potential energy of the capacitor to the final potential energy of a mass (which remained constant for all three capacitors) that the motor lifted. I was instructed...
  4. ikihi

    What is the electrical potential at point P?

    Homework Statement Three point charges of +6.00 μC, +4.00 [/B]μC, and +6.00 μC are placed along the x-axis 0.200 m above the +4.00 μC charge as shown in the figure below. What is the electrical potential at point P (relative to infinity) due to these charges? Diagram...
  5. L

    Irrelevance of electrical potential

    In regards to voltage and electrical potential, I have a question. I understand the voltage to be the difference in electrical potential of two separate points. So in an analogy am I correct to compare this to a bowling ball being 4 feet off the ground. So the bowling ball has a gravitational...
  6. A

    Calculating the heat released in one part of an electrical network?

    Homework Statement An alternating current, with the current value of i = 3*cos314*t, is split into two parts in point A (each part with its own thermal resistance, R1 = 60Ω and R2 = 40Ω), which then connect again in point B. What is the released heat in the part between point A and point B...
  7. Averagesupernova

    Couple of interesting electrical things in an old house

    While cleaning out an old house I found this book. I have later (much) copies of this book that I often refer to. A little mouse chewed but nonetheless a nifty find. Was amused there is a chapter on knob and tube wiring. - -
  8. X

    Calculate the power loss in electrical cable

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  9. J

    Making a 12-24v DC variable power supply

    Homework Statement So, for a school project I have to make a resistance soldering iron. As far as I know, this requires a high current going through high resistance wire (such as stainless steel in my case). I need to make this run from a standard 120v 15A wall outlet. I have figured out so far...
  10. M

    Electrical processes through a membrane - active transport

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  11. U

    Which is better -- amp ground connected to frame or battery?

    There is this debate in car audio forums of this question whether it is better to connect your amp ground to the frame of the car or the battery.. basically they haven't came to a conclusion so I was curious what you guys think... Basically what I mean is that when you hook up an amp in the...
  12. fuvest

    Electrical Circuit Problem / Electric Potential Difference

    Homework Statement In the following picture, the absolute value of the difference in electric potential, between points A and B is: A)5V B)4V C)3V D)1V E)0V Homework Equations E =qV V = iRThe Attempt at a Solution I have no idea where to start on this one, just started my electric circuits...
  13. srinaath

    Electrical DIY wireless power transfer device concept

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  14. S

    Estimation of material loss through electrical resistivity

    Hi all, I'm doing a little project about the wear of materials for tools for cutting machines.Yesterday, I was reading wikipedia page about electrical resistivity and I thought if it might be possible to evaluate the estimate the material loss of the tool through the measure of electrical...
  15. J

    Exploring Electrical Potential Energy Across Series Circuits

    Assuming the resistance of a wire in a series circuit, consisting only of 1 component (e.g. filament lamp) and a battery, is negligible; does each Coulomb of charge commit all of its electrical potential energy, supplied by the battery's potential difference, as work done across the component...
  16. ORF

    How is instantaneous power adjusted in the electrical grid?

    Hello I didn't find a similar question, but if it's redundant, please erase this thread. The instant electrical power is not constant (because of the consumption and of the production). So, how the instant power is adjusted in the electrical grid? There is a similar entry, but it has several...
  17. agargento

    Electrical Energy: 30-Day Output from Coal Plant

    Homework Statement A power plant burns coal and generates an average of 700.0 Megawatts (MW) of electrical power while discharging 1162.00 MW as waste heat. Find the total electrical energy generated by the plant in a 30-day period. Homework Equations W = J/sec The Attempt at a Solution...
  18. I

    Other Math and Electrical engineering

    hello all, I am currently a college student studying energy systems engineering, i was just wondering if there are any ways to get into the habit of understanding math it's not my strongest subject. Also just a random thought, where do you think energy/ electrical engineering will be in the...
  19. UMath1

    Engineering Electrical vs Mechanical Engineering: Jobs, Demand, Roles

    I am a high school senior debating between these two majors. In high school, I enjoyed both Mechanics and E&M very much so its really tough for me to decide which of the two engineering fields I'll like more. Whichever field I pick, I am also planning to minor or double in Physics and Computer...
  20. J

    Programs Can I major in Electrical Engineering and Biology?

    Can I major in Electrical Engineering and Biology and become a Biomedical engineer? I want to be a Biomedical engineer but the school I am going to only has environmental, electrical, and mechanical.
  21. G

    Electrical heating transmission wires

    Hello community. I have a question about electrical heating. I am familiar with the fact that textbooks explain how power losses are reduced by transmitting at high V and low I since P = I^2 X R (equation from Ohm's law and P=I X V) But if you use a different sub for P = I V then you get P =...
  22. A

    Long distance electrical transmission

    Hi everybody... I'm new and was hoping some one could suggest reasonable options for electrical transmission over 1.5 km I live in costa rica wilderness off grid . Electrical power lines are 1.5 km away... brief history... I have electrical lines running 1.2 km to my helpers house ... but...
  23. T

    Engineering Transferable skills and the industries for engineers?

    Hello everyone, I want to give some brief background info about myself before asking; I am a junior/senior undergraduate living in Southern California studying mechanical engineering, and leaning towards the thermo/fluids side of mechanical engineering. However, when it comes to "my true...
  24. Z

    Programs Should I Pursue a B.S. in Mechanical Engineering or Electrical Engineering?

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  25. D

    Cause of multiple paths of electrical breakdown?

    When a voltage gradient across a dielectric becomes too large, the material will break down and become conductive, mostly because of plasma ionization. Thus we get lighning, static electricity fingertip shocks, and tesla coil shows. But often during such breakdowns, there are multiple...
  26. E

    How to calculate the electrical field of planets?

    All, I am not sure if this is the right forum for this but I believe it is the closest to the question I would like an answer to. I would like to calculate the electrical force between Mars and the Earth. I believe I understand that in order to do this, I must apply Coulomb's law: E=...
  27. O

    Electrical Resistance Heating

    If this is not ok to post then let me know, but I have a question that I feel can only be answered here. Question: Would it be possible to heat a 50' semi trailer frame to roughly 400F through electrical resistance, I know it would require a lot of power but the reason I ask is because I am...
  28. K

    Scrapped electrical motor -> generator

    Something like this was on this site, but I'm still not sure if this is possible. I have this concept of taking old appliances, disassembling them, and recombining components in useful ways. I'm wondering if I can use the electric motors, in, eg, washing machines as electrical generators if I...
  29. E

    Electrical power corridor supply

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  30. E

    Engineering Electrical Machines DC Shunt Motor

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  31. Y

    Courses What courses to take to prepare for MS in Electrical Engineering?

    Hi Everyone, I'm planning to apply for MS in Electrical Engineering with specialization in Computer Engineering. I have BS degree in Applied Mathematics with Emphasis in Computational Science. My question is what physics or engineering classes would you recommend to take before starting the...
  32. doktorwho

    Calculate the maximum electrical force on a ball

    Homework Statement A metal ball of radius ##a## is at a distance ##h>>a## from a very long conducting non-charged horizontal metal surface. Calculate the maximum electrical force on a ball under the condition that ##E_{cr}## the critical electric field of air is not breached. Homework Equations...
  33. doktorwho

    The Electrical energy of a conducting cylinder

    1. The problem stsatemesnt, all variables and given/known data A cylinder conductor of length ##l##, inner radius ##a## and outer radius ##b## is half-filled with a liquid dielectric as shown in the picture. The cylinder is attached to a battery of constant voltage ##U## and then separated from...
  34. G

    Analog Electrical Engineer Explores Physics & Astrophysics

    I am an analog electrical engineer by trade engaged in self teaching myself Analysis / Particle Physics and Astrophysics for the last couple of years. I have worked in the computer graphics field for almost 30 years, ranging from hardware / chip design / device drivers and compilers with 30...
  35. D

    How does an electrical signal physically flow in a processor

    I am a high school student interested in electronics. I have been able to understand almost everything about electricity and digital computers mosfets, logic gates,memory,cpu, fetching ,decoding, executing ,clock cycles, etc. except there is one thing that I can't seem to grasp my head around...
  36. G

    System simplification through state space

    Hi guys! I study Electrical Engineering and, don't-know-why, I don't know anything about state space. Now I'm working on a project where I have a non-linear system. The first task in the project is to separate the linear and the non-linear part of this system, and then obtain the state space...
  37. Biker

    Electrical circuits with resistors and variable voltage sources

    Homework Statement The following picture illustrate how the current in the circuit changes when you change ##E_2##. Where slope 1 represents the current flowing through ##E_1## and slope 2 represents the current flowing through ##E2## Homework Equations Usual circuit laws :P The Attempt at...
  38. D

    Quality control testing for an electrical product

    I'd like to test the quality and performance of an electrical item I intend to sell. I was able to find a similar, very high quality product whose quality I'd like analyzed and compared to lower quality alternative. Who should I send these two product samples to? A third party inspection...
  39. cnh1995

    Earthing in Electrical Systems

    I have a few questions about earthing in electrical systems. 1) How can Earth be used as a "conductor"? I googled its resistance and it turns out that Earth resistance is not that large and it can be reliably used as a conductor. For example, I read it can be used as a return conductor in single...
  40. J

    A Where can I find data on electrical conductivity?

    Hi folks, I purchased two books on electric transport at the nanoscale and unfortunately I just found theoretical models and formalism... but the actual data from the experiments was not there. So I am curious about it, I am looking for information on nanowires, quantum dots etc and I would...
  41. Denny Lai

    Optimizing AC Power Supply Wiring for Desired Equipment Setup

    As per the diagram, how do i change the wiring of the equipment on the outside to achieve my desired setup?
  42. V

    Engineering Finding an Entry-Level Electrical Engineering Position

    What are the chances of getting an Entry-Level Electrical Engineering job 3 years after I graduated? I had a 3 year gap because I was getting my teaching degree. However, I did stay current with electrical engineering fundamentals / knowledge during those years.
  43. R

    Electrical distribution network

    I am doing a project for a course and it asks me to draw annotated drawings of the distribution network including generators, transmission systems, distribution system and low voltage loads which in general is all fine. However, I have come across a question that asks me to draw an annotated...
  44. L

    Electrical Engineering conflict

    Hello everyone. I am a third year Electrical Engineering major and I am just starting to take some real EE courses such as Digital Logics and Microprocessors. I have to choose a track for electrical engineering and I am in a dilemma as I do not know which track I want to do. This falls under the...
  45. F

    Question about electrical potential energy

    Homework Statement Two charged plate hold a charge of 3 coulombs with the upper plate being positively charged and the lower plate being negatively charged. They have a pd of 6 volts. There is a spacing of 20 cm between them. A positive charge q with a charge 0.4 coulomb is located at midpoint...
  46. diegovmtj

    Help with two electrical circuits please

    Hey, I am having problems with this. I need help with these 2 circuits I am basically lost and not sure how to start. I need to find voltage, current and potency on each resistance help would be much appreciated, thank you http://imgur.com/trm1On0 http://imgur.com/a/KD3zr
  47. A

    Thermochemistry & Gases in Electrical Engineering?

    I'm a first year electrical engineering student and in my General Chemistry class, every other week, we're required to write a paragraph about how each weeks material relates to your future career. As I am in electrical engineering, I don't see much relation to any topic. This week is...
  48. L

    Electrical charge, current definitions

    What is electrical charge? is it a measure of the abundance of electrons within a system? Current is defined as the amount of charge flowing between any two points in a system over a given period of time, correct? but what is elctrical charge if possible to define it better/further. I am...
  49. Z

    Engineering Find the Thevenin Equivalent Circuit

    Homework Statement Homework Equations Node Voltage Method V=IR The Attempt at a Solution KCL at Node 1: KCL at Node 2: i is the current moving towards "a" I've simplified the two equations down but the problem I run into is that normally I'm able to write a third equation to define i0...
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