A silly question about Electricity...........
carlyn
Posts: 78
;If the current in a live wire runs because the Electrons of that wire are moving along in the direction of current flow; why dose not the wire get thinner ?
Comments
2. The mass of an electron is extremely small in comparison to the protons and neutrons, and the atoms in the conductor are not being depleted of their electrons... there is constant replacement.
3. All the chemical and physical changes you imagine might be observed within a battery.
4. The above are for battery and DC electricity.
5. Magnetic forces can move electronics along in a different manner.
6. With AC electricity, the electrons are actually moving back and forth at 50 or 60 cycles per second.
The electric field moves through a wire at the speed of light, but the electrons move considerably slower through the wire. That is called the drift velocity. However the electrons begin flowing the instant the circuit is complete, so that information moves with the electric field.
It's obvious that the energy of a battery is produced by chemical bonds. What is not obvious is that chemical bonds have a small amount of mass. Now it is probably unmeasurable, but in theory a fully charged battery should weigh more than a discharged one.
There are all sorts of articles on various aspects of materials and conduction in the Wikipedia. Search for stuff like electronic band structure and electron conduction.
If you have ever seen one of these furnaces operate the sound level in incredible.
The conductors on this machine are water cooled wires.
http://www.youtube.com/watch?v=ijWwfcw0FOo
I saw the them moving, but the structure they were attached to was moving up and down.
It depends in what context this statement was made.
That is true at higher frequencies AC, but not at DC. It is called the skin effect. The skin depth for copper at 100kHz is about 0.2mm, and more than 98% of the current in a larger conductor at that frequency would flow within 1mm of the surface. A a tube may serve just as well as a solid wire. I wonder if the water cooling of the conductors in the steel furnace in the video is done via tubes as conductors. The skin depth in copper at 60Hz is close to 1cm.
mike.
In a capacitor current leads voltage, in an inductor voltage leads current (CIVIL). For a resistor there is no such lead/lag and we even have devices with a negative resistance region. Heck most conductors have a higher resistance when hot so effectively their current goes down with voltage so they are negative resitance devices.
So what else is there a passive component can do?
This would explain why resistance creates heat, as the atoms are trying to maintain stability while being subjected to external imbalances. And of course, the heat comes from those electrons converting to photons.
Does that sound right?
The hydraulic model may include a memsistor due to hydraulic conductors being physically tubes that contain and restrain the force while transporting the fluid, while the electrical conductor is not a tube, and electrons can simply be shed from the surface and rely on atomic forces to keep from falling away.
In hydraulics the conductor is simply a physical configuration different than in electricity. Containment of the driving force is quite different.
Nope I mean IR radiation.. via photons... not the conduction of heat through solids. I mean that radiation from the surface of a wire... like the glare of a incandescent light bulb.
Phonons may be an additonal internal factor that determines why copper fails when tungsten just glows. But the fundamental source of the heat is from the movement of the electrons.
There are four fundamental quantities in electrical circuits that are derived from Maxwell's equations. V, I, q and phi (magnetic flux). They are all tied together by time. Q to I and phi to V are simple time derivatives. The constants of proportionality are the familiar R for resistance, C for capacitance, L for inductance, and, therein lies the symmetry, M for memristance.
I can't say I understand it. One of my office mates at college was a grad student in electrical engineering studying with Professor Leon Chua, so I got some idea of the reasoning from him, and later on a family friend worked in the quantum computing lab at HP, where they have been trying to make something practical of memristance at the nano scale in thin films of titanium dioxide.
Professor Chua reasoned from Maxwell's equations directly and was able to show that there are phase plane behaviors that cannot be duplicated with any combination of the standard circuit elements. I don't think I'm stating that correctly. It is kind of an issue of Occam's razor. Just as you can make capacitor and an op-amp appear to be an inductor seen from the outside of a black box, you can make a black box that looks from the outside like a memristor. That is what Chua did. It was only later that HP labs found that a puzzling nano-scale device they had under consideration could best be described in terms of memristance. At first I thought, well, what they had found was just another semiconductor. The memory mechanism depends on migration of oxygen valencies. Not that much different from an eeprom cell, which is basically a long lived capacitor that modulates the conduction in a channel. The crux of it seems to come back to Occam's razor. The memory effect (hysteresis) they observe in these films is easiest to explain when modeled as a memristor. There is a single-valued, nonlinear relation between magnetic flux and charge when reading out the memory, and please don't ask me to explain that, because I still trying to get a grip on it. At the nano scale in metal oxide films, they are dealing with electric fields of thousands of volts per cm, lots of phi there as the charge moves around, I guess.
These days investigators are finding memristance elsewhere, again keeping in mind O's razor. Point contacts, as in old radio detectors, are one example. There are critiques, too, from the standpoint of thermodynamics. Some recent advances create channels by means of picosecond pulses of heat in metal oxide films, and again I am left wondering what makes those memristors, where exactly is the connection between charge and flux? Here is a recent blog that has links to pdfs of current device research.
I think the phonon concept is pretty old. I've always thought about it as the mechanical world's version of quantum-level activity. In other words, if you're humming around at the quantum level of things, then phonons are to mechanical behavior what photons are to electromagnetic behavior. It's where the particle-wave craziness starts to happen to the mechanistic model of the world.
http://en.wikipedia.org/wiki/Phonon
I love it when innocent people get on this forum, ask a simple question, and we all veer off into some esoteric quasi-sensible corner of quantum physics.
Yeee-haw!
Back in the day, we had only 3 states of matter - gas, liquid, and solid... now we have plasma as well.
And while I have long been curious that the relationship of photons to electrons as they seem to me to be the same thing in different contexts... now we phonoms in even a more specific context.
The OP was asking why wires don't get thinner. But it seems to me that if wires were to physically change at all by transmission of EMF, they would get fatter as there seems to be surplus electrons pushing through the wire.
And I begin to suspect when the pushing gets to be a combination of too many electrons and too much force, you convert the electron surplus to heat... as photon emissions.
But this really in a narrow range of scale and temperature. We can observe super-conductors or plasma as conductors and there are separate behaviors. That narrow range just represents the environment of everyday utility.... house wiring and flashlights and such.
Quantum physics seems a bit over-reaching the world we live in and learning electricity as an all-purpose tool. But all that appears to be changing.
Where is your "circuit" then?
What is going on here...?
tell the truth:)
micro-electronics....... it's all a trick. Like that movie where those guys rob a bank and then give the money away.
I like electricity... but where does it really come from? Really?
And don't give me that "11th dimensions" answer... I can see right through that.
The power "leaks through" from the powered board to the other one via the serial connection (try really connecting only the ground wire ... the LEDs won't light up). Remember that a serial I/O connection does supply a little bit of power most of the time. The serial line idles at +3.3V and only drops to 0V intermittently as start bits and zero data bits get transmitted. This power leaks through internal "protective" diodes on the chip to the chip's internal power bus. LEDs will make enough light to see with only a milliAmp or so and the serial line can supply tens of milliAmps.
There may be "magic" out there some of the time, but most of the time, it's just plain, garden variety physics.