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.
Hi guys,
I am a senior EE undergrad at UCLA and will be graduating this spring, 2016. I am applying for PhD programs in EE with a focus on biomedical devices (implantable devices and/or sensor networks and embedded systems).
I am choosing which schools to apply to and would like your advice...
Hello,
I graduated from an accredited University in Canada with a Bachelor of Science in Electrical Engineering. I maintained Honours with Distinction for the duration of my academic career.
I am interested in working abroad, and branching from Canada. I am not sure where I want to go yet...
I understand that electrically charged objects such as a rubber balloon or even the human body can hold several thousands of volts.
What's troubling me is that I know the current that results from an electrostatic discharge is not enough to cause serious damage or kill a human, yet if you touch...
Hey everyone I'm trying to design a simple time delayed device. Device could me mechanical but it doesn't really have to be as long as it does what I want.
Just need something that is relatively small could be wide and tall just not thicker then 1 inch.
The device should have a arm/button...
I'm highly interested in building my own small arc furnace for hobby use. Thus, I want to understand the nature of electrical arcs before proceeding to have maximum control over my design. So far, I know that electrical arcs form when the dielectric strength of the material (in this case, a gas)...
I am currently in third year of EE and thinking about a masters degree
but the problem is here , I've developed a thing for progamming and networking and thinking about switiching to computer science
My question is this
Can i go from EE to as CS for masters degree without having much knowlegde of CS
Hi,
I am 1st year undergrad student at "national technical university of athens" (probably you have never heard of this university :biggrin:) in the department of electrical and computer engineering.
When applying I had a very hard time choosing between electrical and mechanical engineering.(I...
Molecules do not use magnetic energy as latent heat - adding magnetic energy does not cause a phase change. If electrical conduction indeed required energy state changes, then during electrical conduction, a change of energy state would likely consume magnetic energy as latent heat, instead of...
I know that when I get out of school I want to help develop solar roadways, bike paths, and parking lots. Potentially even help with the efficiency rate of solar panels. However, I'm currently a mechanical engineering student with a concentration in energy. The only way to get a concentration in...
Hello! Right now I'm having some trouble deciding whether to continue studying just Electrical Engineering or besides that also start studying Mechanical Engineering. I have heard about mechatronics but that degree is not taught here.
I would like to know from you which career you think has...
Homework Statement
This is quite an easy problem but I'm not sure if I set up my equations correctly, and I want confirmation.
We are given the following circuit:
And our task is to determine the loop currents i_{1}, i_{2}, i_{3}, i_{4} .
Homework Equations
Kirchhoff's first law: sum of...
Dear Forum Memebrs,
Could you please advise if it is possible to think that
in some instances the flow of fluid in P&ID diagram is similar to the flow of electrical current in circuit boards: in order to have an electric current you have to have a potential difference across two points (which...
Is anyone able to explain in basic terms a thick EE student could understand, the significance and a bit about what Guage Fixing, or maybe gauge theory in general is? (or especially for FE simulation)
making heads or tails of
https://en.wikipedia.org/wiki/Gauge_fixing
is not easy. A nice simple...
Homework Statement
So I'm working on question five from my book.
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The book references a earlier problem, which you'll find below for further reviewing purposes.
Homework EquationsThe Attempt at a Solution
I apologize for posting the question as a picture. But given my situation, it...
Homework Statement
A proton is composed of three quarks: two "up" quarks, each having charge +2e/3, and one "down" quark, having charge -e/3. Suppose that the three quarks are equidistant from one another. Take the distance to be 3×10-15 m and calculate the potential energy of the subsystem of...
Homework Statement
The Matricial Circuit of a certain circuit in time-domain is:
[ -1 D+a] [v1(t)] = [es(s)]
[D+2 -1] [v2(t)] [0 ]
where a is constant >0.
Find G1(s) = V1(s)/Es(s). Put your result in a relation of polinomials N(s)/D(s), with the D(s) monic polinomial...
Q1. I know a DMM will anticipate a sineusoidal supply, thus there can be problems with spiky supplies.
Even if you have a true RMS meter, it it's a spikey supply, non-sineusoidal, you still can't calculate the peak of a spiky supply?
Does a DMM measure the peak, then calculate from THAT the...
Assume a conductor in a rectangle shape for simplicity.
Now, if I only choose one side of this rectangle, and apply external electrical field ∑ only to it, what EMF would I create on the conductor? I would simply say ∑, however then I had the following idea, and I started to doubt if I create...
TL:DR Jump to the bottom for express version.
First off a bit about myself. I'm a 25 year old guy from Danmark. I have spent most of my late teenage years and beginning of my 20's, dabbling in different, none schooling things. I have been self-employed and made a living from Online Poker (2...
Homework Statement
Please see attached image 1 and image 2
Homework EquationsThe Attempt at a Solution
Alright so I believe I solved part a correctly. It was very easy.
(A) 5 * phasor of 30 degrees
However it's been a while since I took circuits 1, so I'm struggling a bit with part (b)...
First doubt: The impedance Z is defined how Z = R + j X and the reactance X can be wrote how:
Source: https://en.wikipedia.org/wiki/Electrical_reactance
So, by analogy, the admitance Y is defined how Y = G + j B and the susceptance B can be wrote how what? So:
B = \left( \frac{\omega C}{1}...
Homework Statement
Please see the picture attached.
Homework EquationsThe Attempt at a Solution
I was able to solve part A correctly, at least I believe I was able to do so. I'm struggling with part (b) however. I'm not sure were to start on this. My test that has this problem doesn't have...
Why doesn't SiCl4 conduct electricity when it's in its molten state and conducts electricity when water is added? The answer is C. I know very well what is X and Z, but unsure what is Y.. Why not Al2O3? What's the difference? Does it got to do with their structures? Al2O3 is ionic with a degree...
Homework Statement
I took a few pictures of the circuit, it went across two pages so I took a few pictures, and closeups of certain parts to ensure that all the details can be seen
For the circuit:
http://s7.postimg.org/ywd4nrmsq/IMG_20150905_140403187_HDR.jpg
Figure 1. Overview of Circuit...
Electrons flow from negative to positive. But everything in nature moves from higher potential to lower potential, i.e the charges should move from positive to negative but they don't?
A molecule of DNA (deoxyribonucleic acid) is 2.09 µm long. The ends of the molecule become singly ionized: negative on one end, positive on the other. The helical molecule acts like a spring and compresses 1.09% upon becoming charged, and remains in this equilibrium position. Determine the...
Greetings,
I have a science project to make and i have an idea but i am not so sure about it, the idea is to convert thermal energy into electrical energy which will run a small engine.
I want to put that device in a cooking pan and that heat will be converted into electrical energy which will...
So here is the problem, I major in electrical engineering and my sister works in a small furnishing company and recently the company got an offer to furnish a hotel with 25 rooms.
And she asks me if I can design the electric circuit for that hotel.In school I learn electric machine and how to...
Hi,
I'm already a computer engineer and I'm considering doing a bachelors in electrical engineering. I currently work in the information technology field and I'm kinda not satisfied with the prospects of a career in the IT area, getting a bachelors in electrical engineering should be easy...
hello guys...
i m confused about my carreer,
should i go for electrical design engineer or elctrical site engineer?
which one is better for me?... and how can i get started?
i recently did my Bachelor of elctrical engineering..than
Hi! I am currently trying to determine how the salinity ##S## of a sample of seawater (or, objectively, a salt-water solution) changes its electrical conductivity ##\sigma##.
It is clear that they are proportional since the mobility of the ##\text{Na}^{+}## and ##\text{Cl}^{-}## ions plays a...
Hi there PFers
I'm looking into a variety of areas of research in electrical engineering at US universities. For instance, looking at the University of Texas page, there's a research specialty in EE called "plasma/quantum devices and optics."
Now, this looks very interesting to me. I was...
In case of power transformer,what is the difference between electrical fault and thermal fault?
I want to know that if internal fault is occurred in power transformer then on what basis we can differentiate electrical and thermal fault?
I need a switch that will alternate the flow of electrical current between two diverging wires at a decided rate. Are there switches that function this way? What are they called?
Hi,
I want to be an engineer but am not completely decided on what kind. I was wondering if I get a general engineering degree and get a specialization in electrical engineering, will this allow me to pursue a job as an electrical/electronics engineer out of college? Any help would be...
I want to build high voltage feedthroughs (vacuum) from epoxying pieces of alumina together, and then epoxying alumina strips on the outside to cover the spaces between. Can I use JB weld, as far as things go electrically? People have reported that JB weld is unexpectedly wonderful for vacuum...
Hello, this is my first post there though I have been on this site before to look for answers to questions.
I am a graduate in Electrical and Electronic Engineer, graduated in 2013 and live in London. I currently work for a engineering consultancy working on telecoms systems work...
Hello,
I am in a calc 1 general physics 2 summer session class and missed the lectures on this due to sickness. I'm really confused on applying coulomb's and gauss's laws to find the electrical field of a sphere or outside a sphere. This is of both variable and constant charge densities. I've...
Hello
I made a little wind turbine so when it is directed at wind it turns and generates electricity as I can see the outcoming voltage on voltmeter. My question is how can I store its energy?
Can I use a rechargable battery and let it run out, then stick copper wires at each sides of it coming...
Hello,
I am currently pursuing my BS in EE. I am interested in avionics and would like to eventually work in the aerospace industry. What sort of topics should I focus on?
I did an initial search on the forums and people have noted that these subjects are relevant:
- Control Systems
-...
Hi all, I am trying to decide between double E and physics with EE electives. I really love to learn theory and about what is happening at the sub atomic level however, I really enjoy designing, prototyping, and building electronics circuits, learning about all the components, how they work, and...
i am currently studyin fo r my barchelor's degree in meteorology and climate science ...but i really want to pursue electrical engineering for my grad schools...is that possible?...if not what wld be my best option for any ms study with the degree am currently pursuing ..considering job...
Hi,
I graduated with a B.S in Economics from Florida State University about 3 years ago, but now I'm looking to switch fields. Can anyone tell me about the EE undergrad program at Florida International University?
I'm considering FIU because I can live with my parents for a while and save a...
Is majoring in computer engineering the same as doing a double major in electrical engineering and computer science?
Hi,
I'm having difficult choosing my major as an upcoming freshmen at the University of Waterloo. I'm very interested in both the hardware and software aspects of computers, but...
I have always been interested in Engineering and a while back I could not decide between Electrical and Mechanical. However, I chose Mechanical, but now that I see that almost every invention nowadays are in electrical engineering field (I want to be an inventor) I am upset!
So anyhow I was...
What's up people? I'm new in this wonderful forum. I have several questions about circuits, and they are not really common, I mean, I find them somehow complicated, but I would really come to enlightenment if you guys gave me some clues.
1.- So, let's suppose we got the simplest circuit, a...