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, I've got two computers that are in separate rooms and I have placed plastic conduit through the small space above the ceiling. Which will have a USB data cable, an Ethernet network cable, and a HDMI cable inside. The conduit length is about 8m long. And I was wondering if this setup could...
Dear Sirs,
If I take this explanation as being true "The heat is generated on the microscale when the conduction electrons transfer energy to the conductor's atoms by way of collisions."
So a "current" must have a quantum of kinetic energy going into the conductor (resistive element) and a...
Homework Statement
One of the two glass panes in each window is coated with a transparent electrical conductor. Why does this coating improve the window's insulating ability?
Select one:
a. The transparent conductor is black in the infrared, with a low-temperature emissivity of almost 1.
b...
This thought experiment has been bugging me for a very long time - I'm hoping someone can help me understand it.
Premise:
- Simple DC electrical circuit consisting of a battery, wire, light bulb, and another wire to complete the circuit.
- Each wire has a length of 1 light-year (yes, very...
So I have been wondering:
The potential for a point charge at the origin, is described as:
(Using the reference point at infinity): V=1/(4πε) * q/r
My question is, what happens to this Potential the closer we are to the point charge, and so the closer we would get, the Potential seems to go...
How is symmetry used to solve electrical circuits? I have seen several problems in books in which currents in two resistors are said to be equal due to 'symmetry'. That is a concept that I fail to understand and thus cannot apply. In class, we were shown a few circuit diagrams which were...
Can anyone recommend a place to find case studies in electronics design? I am looking for concrete examples of the engineering process from requirements definition through PCB layout.
As a physicist who designs instrumentation I would like to improve my improve my design process and employ more...
I have been looking everywhere for a clear explanation for the following: How do I know which way to integrate the electrical field, when I'm looking for the potential between to points?
Example:
I have to find the potential between the top conducting plate and the bottom conducting plate...
Hi, I’m a freshman Physics major in the US and I am concerned about the job opportunities directly out of undergrad. Because of this, short of switching my major to an engineering field, I was wondering if a minor in EE would substantially assist me. I know it would not be an ABET accredited...
After watching a video on YouTube, I recently became interested in the dynamics and physic's of why we aren't using electrical powered planes instead of burning thousands of fossil fuels every day. After doing a bit of my own research, I found the problem. When we increase the weight, we have to...
Homework Statement
Homework Equations
P=V2/R
For maximum power transfer,
Rload=RThevenin
The Attempt at a Solution
I know the efficiency is 50% during maximum power transfer. So when all the sources are acting simultaneously and ( at the same time) R=Rth, maximum power will be dissipated in...
Hi,
Is it true that the transmission of energy is not inside an electrical conductor, but outside the metal. this even for frequencies around 50 hertz.
Thank's
Do electrical engineers actually use stuff that is taught in Circuit Analysis classes like Node Voltage Method, Mesh Current Method, Kirchhoff Voltage/Current Law, Source Transformation. All these usually only involve resistors. Are they somewhat altered in a way to analyze circuits with other...
Homework Statement
10 v, 100 hz goes into a circuit of a 1o resistor, a 1o inductive reactance and a 1o capacitive reactance that are in series.
What is the current. What is the V across the cap.
Homework Equations and the attempt at a solution[/B]
So I know I = V/Z and Z = sqrt( R^2 +...
We most often witness the presentation of quantum dots in viles or containers which are excited via UV light.
I am more interested in their electrical excitation.
Could I simply take a sample of QDs from one of those viles and passing an electrical current through that sample excite the...
I comprehend that the above statement is not phrased as a question even though it contains the appropriate symbol, and that is because even if it was, and an appropriate answer was given, i believe i still would not be able to make a decision. It is more a reflection of my current mental state...
Hi lads,
I couldn't find this info on Google...
Are the Heart and Brain the only organs which physiological functions are based on electrical impulses?
What happens if we apply electrical current through other organs?
Thanks
Some spiders are known to fly on the breezes by extruding silk strands (like web material) from their abdomen. This is commonly thought to be caught in the wind and carry them away. This would explain the occasional spider you might see drifting by when you are outside.
Many (including that...
Hi,
I'm sorry if this question's been asked before but I was wondering how hands-on electrical engineering can be.
Are there jobs where an EE can find themselves doing designing and getting to work with their hands?
I find the theoretical stuff interesting as well as the more hands-on work.
The Faraday effect is a magneto-optical phenomenon caused by the interaction between light and a magnetic field.
Is there a corresponding electrical-optical phenomenon, caused by the interaction between light and an electric field?
Homework Statement
From Griffiths Third Edition: "Introduction to Electrodynamics" p.p. 81 ex. 2.6
"Find the potential inside and outside a spherical shell of radius R, which carries a uniform surface charge. Set the reference point at infinity.
Homework Equations
V(r) = -∫E⋅dl
The...
I'm in year 11, doing Physics for GCSE and my actual ending GCSE is on Friday which Is where I finish school.
I'm 16 and in the UK, I need help with the following equations:
P = I^2 x R (why is this equation used)
- all the power equations
- How to calculate uncertainty
<< Mentor Note -- OP...
OK, so my last post seemed meaningless.
Can anyone help with this, I understand some of you say current moves from the positive terminal of a battery to the negative terminal and some say the opposite.
Lets say it is positive to negative just for this question.
If I have a battery that the...
Thank you for your time and effort. It is much appreciated.
1. Homework Statement
I have attached the problem with the solution to this thread. Basically, the problem asks to construct the circuit model for a generic device by using the data of terminal current and voltage measurements. From...
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