Speed Of Electricity

Thanks

Thankyou all,

This has been very interesting, especially the part that insulation plays.:D
 
TrueSceptic said:
Thankyou all,

This has been very interesting, especially the part that insulation plays.:D
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To be more precise, it’s the dielectric between the conductors as per PingofPong's post. As a practical matter this must be an insulator.

I forget whether it was mentioned, but the same equation will give you the speed of light in any medium. If you recall it’s the speed of light in a vacuum that is constant, light traveling trough some other medium will move more slowly.
 
lomiller said:
To be more precise, it’s the dielectric between the conductors as per PingofPong's post. As a practical matter this must be an insulator.

I forget whether it was mentioned, but the same equation will give you the speed of light in any medium. If you recall it’s the speed of light in a vacuum that is constant, light traveling trough some other medium will move more slowly.
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Indeed. Where would we be without the "magic" of refraction. :)
 
Paulhoff said:
When people sell wire for thousands a foot, they are having people.

Paul

:) :) :)
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I know what you are getting at but my question was "where would we be without the magic of refraction".

The way I see the audiophile cable business is in terms of "fools and money". Anyone who can spend $xk on cables without a provable result doesn't get much sympathy from me.

(Confession: I enjoy high end audio and know that cables make a difference, but only when there are obvious measurable reasons. I will pay for quality at a reasonable price but not Nordost prices.)

But how does all this relate to the OP?:)
 
TrueSceptic said:
(Confession: I enjoy high end audio and know that cables make a difference, but only when there are obvious measurable reasons. I will pay for quality at a reasonable price but not Nordost prices.)

But how does all this relate to the OP?:)
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At audio frequencies, little to none, any good gauge does the trick.

Paul

:) :) :)

And seeing that no one is posting.............. but us............
 
TrueSceptic said:
(Confession: I enjoy high end audio and know that cables make a difference, but only when there are obvious measurable reasons. I will pay for quality at a reasonable price but not Nordost prices.)
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But the issue isn't whether the differences are measurable - I'll bet I can measure differences between two "identical" cables. The issue is whether the differences are large enough to be audible - if not, who cares?

And it's pretty hard to screw up a cable badly enough that it makes an audible difference (although I'm sure it's been done).
 
sol invictus said:
But the issue isn't whether the differences are measurable - I'll bet I can measure differences between two "identical" cables. The issue is whether the differences are large enough to be audible - if not, who cares?

And it's pretty hard to screw up a cable badly enough that it makes an audible difference (although I'm sure it's been done).
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What I meant was that the difference between, say, hefty speaker wire and bell-wire is audible. That difference would be for measurable reasons, not the woo that some (many?) audiophile cable companies espouse.

I find it interesting that Linn and Naim, 2 of the UK's top hi-fi makers, make cables that are "common sense" and sensibly priced.
 
TrueSceptic said:
What I meant was that the difference between, say, hefty speaker wire and bell-wire is audible. That difference would be for measurable reasons, not the woo that some (many?) audiophile cable companies espouse.

I find it interesting that Linn and Naim, 2 of the UK's top hi-fi makers, make cables that are "common sense" and sensibly priced.
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There are a few makers of audio equipment that try to be as neutral as possible about the woo-woo wire because they want their speakers to be sold at audio stores. If they come out and say it is woo-woo they may not be sold by these stores because there is a big mark-up on woo-woos wire and the store wants that money.

Paul

:) :) :)
 
TrueSceptic said:
What I meant was that the difference between, say, hefty speaker wire and bell-wire is audible.
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I don't know what bell-wire is, but even coat hangers can't be distinguished from "audiophile" speaker cable.

Very long thin wire can be because its resistance significantly reduces the volume. In principle it also affects the frequency response of the speaker (by acting as a voltage divider for a complex load), but I've never seen any test that indicated that speaker cable audibility couldn't be entirely accounted for by level, and even then only in absurd and totally unrealistic circumstances (30 feet of 24 gauge wire or something).
 
sol invictus said:
I don't know what bell-wire is, but even coat hangers can't be distinguished from "audiophile" speaker cable.

Very long thin wire can be because its resistance significantly reduces the volume. In principle it also affects the frequency response of the speaker (by acting as a voltage divider for a complex load), but I've never seen any test that indicated that speaker cable audibility couldn't be entirely accounted for by level, and even then only in absurd and totally unrealistic circumstances (30 feet of 24 gauge wire or something).
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I know the theory. I'll look at your link and see what else I can find.

Bell-wire is the extremely thin stuff than connects your door bell (or chime) to the button on the outside. It is sort of a joke term for the worst cable you could use, even if it might not be true, as in here.
 
sol invictus said:
I don't know what bell-wire is, but even coat hangers can't be distinguished from "audiophile" speaker cable.
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I've got a bone to pick with you. Thanks to that link, I know about the Canon EOS 5D MkII. I've been putting off buying a digital camera for, well, ever, because nothing yet has everything I want. The wait is now over and I have to find the money! ;):mad:;)
 
The speed of an electric signal travelling on a cooper cable is about 1/3 of the stadard speed of light. Light travelling in intermediate quality optical fibre is about 2/3 of the stadard speed of light.
This can be easily measured.
Why these speeds are different from the standard and still called speed of light I believe it has already been explained. It’s because of the different electromagnetically constant for the material being used. But electrons do not necessarily travel at the speed of light.
 
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PingOfPong said:
You may wonder how a DC signal can be a wave. Without getting into the math, a DC signal can be decomposed into into an infinite sum of waves (Fourier analysis).
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Pedant speaks:

Well, you're talking about a step function, strictly speaking, when you turn on a DC signal, so it's not a "DC" signal, which will have support only in the DC basis vector, but rather a step function, which has support at all frequencies, with 1/f amplitude, if I recall correctly. (it's an integrated impulse, which is flat, so it's 1/f, yes...)
If you're asking about the movement of individual charges then that depends on drift velocity which is determined by the properties of the material at the atomic scale.
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Some numbers to consider. 1 mole of electrons is 6.02 * 10^23. That's about the number of electrons in 2.2 ounces (give or take) of copper. That's a few feet of not really big sized wire.

1 amp is 10^19 electrons/second passing a given point, give or take. So, 6*10^4 amps is what you get if one mole of electrons passes a point in one second.

That is a LOT of current. If you put 1 amp through the wire (say it's 10' of wire, which would be moderately small for such a current at 1 mole of copper), you'll have the electrons (we're assuming DC here) drift 10'/(6*10^4) feet in one second.

But the signal will get there with most of the speed of light. Typical propagation is well over .5 C, most wires are about .8 C, and the slowest stuff I'm aware of is about .3 C, and that's not what we use for electrical wiring (and is kinda rare, and used for delay lines).

Figure .8 feet per nanosecond, as a good rule of thumb.
 
Paulhoff said:
There are a few makers of audio equipment that try to be as neutral as possible about the woo-woo wire because they want their speakers to be sold at audio stores. If they come out and say it is woo-woo they may not be sold by these stores because there is a big mark-up on woo-woos wire and the store wants that money.

Paul

:) :) :)
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trVth

Just like "biwiring" (which exists primarily so that the wire seller can sell not one, but TWO sets of speaker cables). I asked two prominent (good) speaker manufacturers, both of whom said basically "yeah, we have to...".

The "primarily" above refers to the point that if one makes a good crossover, it's not necessary... I'll allow you to proceed from there at your own pace.
 
TrueSceptic said:
I've got a bone to pick with you. Thanks to that link, I know about the Canon EOS 5D MkII. I've been putting off buying a digital camera for, well, ever, because nothing yet has everything I want. The wait is now over and I have to find the money! ;):mad:;)
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Sorry :gasp:.

I've been doing the same though - I'll have to have a look :).
 
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