Voltage is like potential energy, like when you sit in a chair there is enough potential energy to let you fall out of it. When you fall out of your chair the potential energy is lost because then you are no longer in your chair. The change of voltage from a voltage level to ground level would then be like you falling out of your chair. When the potential energy is lost you would no longer be in the chair. Then how much you weigh and how fast you fall determines how much work could be done from you falling. http://en.wikipedia.org/wiki/Electric_power "Electric power, like mechanical power, is the rate of doing work, measured in watts," The transfer of a voltage then creates a current. This current is then able to do work, and is power as described as wattage. So then you have to have a volatage, difference in potential, in order for it to be able to create a current that can then do work. "An electric current is a flow of electric charge through an electrical conductor" - http://en.wikipedia.org/wiki/Electric_current
Exactly the point I was trying to make, they try to make it sound like the speed of electrons is slow but that is okay because there is a voltage that is close to the speed of light. It has a lot more to do with just the electric charge between two points, that works at the speed of light. Circuits do not operate quickly just because the volatage alone is transmitted at the speed of light. All of the extra electrons at point A would then be at point B if there was no volatage level between them. Changes in voltage can happen very quickly. You would know all the extra electrons creating that voltage have moved when there is no longer a voltage between the two points.
Power=work/time. When we speak about force, work, power, distance, time, and acceleration we are speaking about what already occurred in the past. You want to know how much work you did when you lifted a 100 lb rock 3 feet away from the axis of the earth? The force is 100 lbs. The distance is 3 feet. The work=force*distance, so the work is 300 ft-lb. If it took you 3 seconds to lift the rock then the power is 100 ft-lb per second. 1 HP=550 ft-lb of work per second, so 100 ft-lb/sec=.18 HP. As you see, all you are doing when you talk about work and HP is you are taking measurements of actual force, distance, and time, and you are calculating the work that was done in an elapsed time, and that is called POWER!
electrical power in watts is current in amperes squared times the resistance in ohms. the formula can be re-arranged for either I, R, and E
Very well origin, as you request: A very brief comparison of the old Drude model with QM based Sommwerfeld one is at http://tau_nanophys_kth_se/cmp/hall/node1_html (replace all underscores with dots) Try looking through pp30-40 the PPT presentation here:http://tinyurl_com/b77scjn (fix the underscore!) I just created this one at tinyurl.com (note that Sommerfeld model is a vast improvement over Drude model, but still has significant deficiencies that more modern approaches correct. But ballpark re conductivity/drift velocity relation in most metals.) It is the significant vector biasing of conduction electron emission/scattering processes in Sommerfeld model that leads to a very high mean drift velocity. I have a pdf converted article, no longer available online, that gives a very nice pictorial+basic math explanation. If you want, PM me and will post it to you. You can then post it here for all to see. Up to you.
True, unfortunately the remainder of your comments fall in the latter category. Nonsense. That notion would lead to electricity traveling at the speed of sound. This much is true if one qualifies by mentioning the dielectric constant of insulation involved for coax. Yes I doubt what you say. I have given references in answer to origin in above post backing my contention in #10. Show me it's wrong.
The speed of the electrons in a copper wire is indeed about .00029 m/s It's called the drift velocity. http://en.wikipedia.org/wiki/Drift_velocity The electricity, the electromagnetic wave, moves at a velocity of .95c to .97c in copper wire. http://en.wikipedia.org/wiki/Speed_of_electricity
Your first link does not work, but not hard to find the article. It's an example imo of the truism that Wikipedia cannot always be relied on. Regarding the specifics here, that article uses a very simplistic notion of counting all the free electrons - aka a Drude model analysis. In some ways no real harm done as grossly inaccurate factors cancel out in the end and it manages to yields an overall conductivity figure about right. However it woefully fails in other areas like cyclotron resonance, thermal conductivity etc. For the real picture, try consulting a book on solid state physics. My only one handy is 'Solid State Physics, 2nd Ed'n', J.S.Blakemore. If you can get a hold of a copy, study p185 and thereabouts. Backs up what I have claimed.
I'm not about to be bothered by you and your silly request. I happen to be a retired researcher and have dealt with such matters first-hand. The figures given in Wikipedia ARE correct. If you don't accept them, it's *your* problem, not mine nor anyone else's. <shrug>
What kind of research exactly? One that wasn't bothered by way outdated models of solid state behavior it seems. Then you don't accept the explanation given in #30. Fine. Just remember this - it was you that came out swinging in #18. My response has been in kind.
the conduction of wire and the conduction of semiconductors, transistors and the like, are 2 different processes.
Absolutely true in general, but conductivity in metals is covered in solid state physics textbooks like Kittel, Mermin, Blakemore etc. and that's where I'm saying accurate info is to be sourced on this issue. As stated back in #10, there is much disinformation out there, even in popular general physics textbooks. Strange but true.
Electrons act as both particles and waves. The electron particles moves slower than the electron waves in electricity. If you consider a generator being driven say by water power. The rotation is generating waves not particles, so the generator never becomes electron deficit equal to amount of current it generates. The wave functions are constantly generated by the rotating magnetics but the metal parts do not quickly oxidize due to constant release of electron particles. If particle movement was the case, the electrons generating the magnetic fields are the higher energy level. If electrons particles flowed the magnet would wear out as it loose the electrons that generate the magnetic field. This would happen in hours. But they last for years because there is only a slight entrainment of electron particles, with most of the action via the wave motion.
I did not look at the other link because I do not like to download things from unknown sites. So just looking at the first link, I have to ask, what do you think that it is telling you? Because clearly it does not support your point. The electron velocity \( V_f\) is the fermi velocity of the electron itself - NOT the drift velocity. The high speed electron has many collisions resulting is a tiny mean free path and a resulting drift velocity in the range of fractions of a mm/sec. Nothing new here and this Fermi velocity can be used to help calculate the drift velocity. So it looks like my physics book has not been shown to have 'urban legends' in it yet! Go back and read your link carefully. If you have any questions about the link I am sure there are many people on this site that can help you.
they are separate processes. there is simply no way you can get the tunneling effect from wire that you can get from transistor material. this in itself shows electrons behave differently in wire than they do in transistor material. yes, i already know about such things.
The following is applied on a daily basis in the design of computer boards: 1. Open wire parallel lines that are mostly air with periodic bits of insulation to maintain spacing have velocity factors in the range of 0.95 to 0.97. 2. Most coax has an insulator of either polyethylene, foamed polyethylene, or Teflon with velocity factors of 0.66, 0.8, and 0.7 respectively. 3. There are air spaced coaxes where the insulator is plyethylene in periodic lumps as opposed to being continuous down the line that have velocity factors in the range of around 0.85. In conclusion, the electric current travels at a very high fraction of c in conductors. Daily experience confirms it, if it weren't true, the computers, celular phones, etc. would function different from the way they do. They don't, therefore Q-Reeus is correct.
Hi Tach. Thanks for the one-up but in a way not deserved on that basis Please Register or Log in to view the hidden image!. I agree entirely with your observations re signal speed in conductors and circuits and how it depends on dielectric properties and configuration of insulation. However there is no direct correlation between signal and conduction charge speeds, the latter being maybe around 0.3 % of c in air. That's around a billion times greater than the figures often bandied about here, but still far short of signal speed. If I can find them, will post (crippled) links to some interesting articles that show animations of just how it's the surface electric fields of a conductor that determines it's signal behavior. Not what one might think!
True. But when a current is applied through a 100 meter conductor, an electron at one end of a does not exit the other end of the conductor in \(10^{-6} sec\).
