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.
Hello everyone,
I am looking at two master's degree programs (graduate school) : electrical engineering and robotics. Taking decisions is hard, and I would gladly like some advice making up my mind.
I have a bachelor's degree (undergrad) in electronics and electrical engineering, which grants...
I did try redrawing the circuit at steady state , but I'm not really sure. I have attached the circuit that I tried drawing, I assumed the branch with the capacitors to be absent at steady state since current won't flow through them anyway. With this diagram I get the correct answer for Q 19 ...
Hello hope everyone at PF are keeping well!
Looking at this problem but don't know if I have oversimplified it and my final answer doesn't seem right?
So I drew the equivalent circuit:
Then went onto calculate:
I1 = 1/(R1+RL1) = 0.01A
ω = 2πf = 2π*109 rads-1
so then with Vi being the inducted...
If we look at system at constant temperature and volume which is galvanic cell, first law of thermodynamics states: $$ dU = dQ + dW' $$
Where W' is electrical work done by galvanic cell and Q is heat exchanged with surroundings.
As far as I know electrical work is work done by electric field...
Basically this would be a closed loop geothermal system for electrical power generation. The system would consist of 2 Horizontal Wells connected creating a U-shaped closed loop cycle using thermosiphon effect, with constant recirculation. It's not really a conventional geothermal power...
In this thread, I hope to find some help in understanding one of the first application of Faraday's law of induction: the "Barlow's wheel".
Basically the machine converts electrical power to mechanical, so as you can imagine, a battery, some conductor wires, a horseshoe magnet and a metal wheel...
Hello guys!
I am a student who currently works on a project based on electrical detection and voltage measurement in electrical cables remotly. So in order to accomplish my work, I'm seeki ng for new ways to detect voltage. I already have some ideas such as using magnetic fields or measuring...
As we know that the magnetic induction causes an electric current in a wire and Faraday has formulated his Electromotive equation ##\epsilon=-\frac{d\Phi}{dt}##. And then Maxwell-Faraday's equation is: ##\nabla \times E=-\frac{\partial B}{\partial t}##, until now this was just an introduction...
Hello everyone !
I'm working on ultrasound probes, and I wanted to measure the electrical signal generated by a piezoelectric device (a transducer).
Here is a sketch of the experiment :
The goal of the experiment is to compare the electrical signal of the piezoelectric cell and compare it...
I have been studying the representation of generators in power flow studies and I would appreciate your comments in this thread.
From the book Fitzgerald & Kingsley's Electric Machinery, I understand that there are unsaturated and saturated reactances.
In section 5.3.2 of the book it is said...
I thought up of this problem myself, so I do not have solutions. I would appreciate if you could correct my approach to solving this problem.
Firstly, the charge induced on the inner surface of shell B is -q, and so the charge on the outer surface of shell B is Q+q.
The energy stored can be...
Long time lurker, first time poster.
I did my undergrad in EE. I'm looking to transition into something in the biomedical space, particularly tissue engineering. I might want to do a PhD, but I'm just seeking a new challenge at this point in my life. Is there any way that I can work part-time...
I'm not sure where this belongs, I'm guessing biomedical, but I'm interested from a physics perspective.
Do neurons generate an electromagnetic field? In other words, all the neural activity in the brain, does it generate electromagnetic fields?
If so, what are the details of these fields?
I...
The Vacuum Permittivity of the classical vacuum seems to be for just conversion of units in Coulomb's Law, like Coulomb's Constant in disguise.
Does the Electrical Permittivity of the Vacuum in classical electromagnetism have any real physical significance other than in the above context...
I’m doing a project with my Arduino, and I’ve seen some tutorials on YouTube explaining how to use pull up or pull down resistors to make the input values on the board reliable, basically either a 0 or a 1 without any random changes from other em sources.
The only thing is I still don’t...
I have need to put some chemicals INSIDE a home electrical appliance which is a closed area. I am thinking and worried that if electrical parts could react with chemical and cause problems? The only
possibility I can think of is if the spark from electrical appliances could react with...
So I am working on a project where I have a tank, which has a volume of electrolyte liquid inside it. This is coupled to a battery which charges it, and gives it energy. I will have a copperband arround it, so i can measure a potential voltage from the electrical field.
So what I need to...
I am in a team of designing a 33KV potential transformer. We done secondary turn as 75 and primary turns as 15000 with core cross sectional area of 5000 sq.mm. As per IS standard we need to maintain a accuracy class of 0.2 at 50VA burden but we can't able to achieve it. Someone please help us to...
Assume that a certain charge distribution ##\rho## generates an electrical field ##E_{ext}## in the surrounding space. We also note the corresponding generated potential ##V_{ext}##.
Assume furthermore that a conductor A, with a definite shape and volume, is placed in field ##E_{ext}##, and is...
I'm not an electrical engineer.
I'm a truck driver. So please don't expect me to know much about electricity. This is a serious question.
If an electrical part (such as the contacts of a contactor) has no voltage, can the electrical part shock a person while the electrical part has no voltage?
Hello everyone,
Is there a straightforward way to determine the electrical properties, such as the dielectric constant (or function), of a molecule (for instance, a metal oxide)?
I understand a simple weight-average model wouldn't work for various reasons.
Thanks so much!
I do not really know the relationship between potential energy and mass difference.
Isn't the difference in mass of protons and neutrons due to their quarks? (the neutron is made of two down quarks and an up quark and the proton of two up quarks and a down quark.)
Please help.
I'm faced with a puzzle. Lately my desktop PC requires me to first disconnect, and then reconnect its mains cable, before it will start. By this I mean the cable has to be physically disconnected from the mains socket, as well as disconnected from the male plug that goes into the back of the...
I am not sure if i can explain my question properly. I am studying the Generators section in the magnetism chapter. As i mentioned the statement "The rate at which work is done is exactly equal to the rate at which energy is dissipated in the resistance". When the term dissipated is used does it...
This question is an example in Durcell's Electricity and Magnetism.
The solution goes as follows:
[In this case] there are four different types of pairs. One type involves the center charge, while the other three involve the various edges and diagonals of the cube. Summing over all pairs yields...
I am open to ideas of a way to test a bus bar for insulation flaws that has a 3D shape that varies in a production environment.
I have a DC bus bar that when it was just straight we would run a high potential test on a metal table that is the reference plane, and then flip it over to test the...
Hi everyone
Hopefully I am not out of line posting in this forum.
I am looking for some advice planning the electrical system for my camper van. I know very little about electrical circuits and all related to it, and after 4 days of research I am still nervous to spend a lot of money and...
I'm trying to better understand the physics of how Earth ground works.
In circuit analysis and other electronic courses they usually present a conceptual picture like below where the Earth is viewed as a path that completes a circuit? In this conceptual view, the current travels on the...
Through my 2 analog classes and 2 electronics classes I have learned about resistors, inductors, capacitors, BJTs, Mosfets, and FETS. What are some other fundamental components that I should be taking a look at? To add to this, I don't consider gates as fundamental because they are built up from...
Arcing in a contact occurs due to open and close action of the switch. I am curious if the arc intensity depends on the type of load. For example the arcing (arc intensity) due to induction load will be greater than arcing due to resistive load?
I quite understand the fact the EPE (Electrical Potential Energy) of a system of two charges are U = k*qQ/r, Q is fix. however when it comes to three charges i get lost. because my reasoning is :
if q1 is fix then the EPE of the system when q2 is brought is U2 = k*q1*q2/r12, when q3 is brought...
Suppose we have a connected electrical network with only resistors. We also assume that each vertex is connected to at least ##k## vertices, where ##k\geq2##. Suppose all resistors in the network has resistance between 1 and 2. Suppose we flow 1 unit of current from vertex ##a## to vertex ##b##...
I am writing tutorials for my students on electrical circuits and I realized that in English I may have been using incorrect terminology (I also teach in French).
When I describe circuits, I like to have a term for a section of a circuit that goes from one node to another node and with no...
Now don't get me wrong. I often compared electroshock therapy to trying to shoot an apple off someone's head, blindfolded, with a flamethrower. But what I want to know is are there electrical conductive frequencies that can travel through the human body without causing damage to any of the...
Hello, I have answered the question below but would like some advice on whether I can improve my answer or if anyone is able to check whether I have made any mistakes ?
i. 1 V = 1eV in a 1:1 relationship, therefore;
6.5 TeV = 6.5 TV = 6.5 *10^12V
ii. E=W
W=V * Q
Q=number of particles * charge...
Can someone give me some insight into what would happen at the motor terminals and on the line if 2K2 (run Contactor) and 2K3 (auto xfmr wye contactor) were to close simultaneously. There are interlocks to prevent this, but I would like to know out of curiosity. My theory is that you would have...
I’m trying to learn about simple circuits but I have a few questions because I don’t fully understand what’s going on .
1. If the reason current flows when a wire is connected to the ends of a battery is due to a potential difference across a battery , why can’t the current just flow through...
Hi all,
I'm going to graduate this May with a degree in Electrical Engineering. While I've done pretty well, my passion was never in EE and I'd like to aim for graduate school in Computational Neuroscience. When I look at the background and methodology employed by many favorite (current)...
You see this symbol on power switches, but what does it really mean?
From https://en.wikipedia.org/wiki/Power_symbol,
But the switches that I've seen the symbol on doesn't cause a "sleep mode" but powers the device on and off.
... Grrr
Hi All,
I am just trying to understand a circuit but cannot figure out the meaning of the following symbol. Did not get very far from googling electrical symbols.
The symbol is given below. I know it is a switch but what does "x" mean on one of the wires and what do the half sine and square...
I’m a freshman in undergrad and I currently attend the University of Illinois at Chicago. I major in electrical engineering but I have an extremely strong interest in physics, chemistry, and materials science.
UIC doesn’t have a materials science program, but George Crabtree, a highly cited...
I don’t know the ratio of the CT. I’m just looking for an explanation on this. I thought in order to measure output voltage you need to pass the current through a resistor and read the voltage drop.
A co worker put 400a through the CT and measured 130v. Something just seems off to me. Can you...
I’m self taught so I have a lot of holes in my understanding. I also have little to no mathematical understanding. Even though ironically, I tend to prefer to picture electricity as numbers rather than “water” in a pipe, etc.
I’ve been studying displacement current recently and have a question...
Really coming at this from a radio perspective, where texts refer to closed and open circuits as jargon; never defining. A transmitter sending waves to feed line lacking an antenna = open circuit. Check. A wire of little resistance errantly falling across circuit lines = short or closed...