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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#1
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conduction
If two conductors are merely touched together electricity can flow
between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. Even if the conductors aren't touching, sometimes there's a spark. Another question. Why do I wonder about such things? Bill |
#2
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conduction
On 03/06/2021 14:02, williamwright wrote:
If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. Even if the conductors aren't touching, sometimes there's a spark. Another question. Why do I wonder about such things? I guess touch points are a singularity, but while they represent a small diameter they also represent a very short one too. R = p(resistivity) x A / L As L tend towards being infinitely short then the resistance from touching conductors is minimal. Nothing wrong with trying to understand things that aren't immediately obvious. BICBW |
#3
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conduction
On 03/06/2021 14:02, williamwright wrote:
If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. In metals there are usually an abundance of free electrons - these are very easy to separate from the atom which they orbit, and move to another one close by. Hence any conductive atom in close proximity can share its electrons, and allow a current to flow. Even if the conductors aren't touching, sometimes there's a spark. Air is an insulator, but it has a breakdown voltage (aka "dielectric strength") where given enough voltage or "electrical field strength" you can rip electrons from the atoms, even though they are not usually "free". The insulator is then said to have become "ionised" and will become conductive at least while the material remains ionised. The point at which this happens is an intrinsic property of the material, but it's also a function of distance distance. For air you need a voltage difference of around 3kV/mm to cause a breakdown. o to get a spark to jump a metre you need a megavolt, but only 300V for a tenth of a mm and so on. Another question. Why do I wonder about such things? Because you are a bright spark ? -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#4
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conduction
On 2021-06-03, williamwright wrote:
If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. Even if the conductors aren't touching, sometimes there's a spark. Another question. Why do I wonder about such things? It is all part of the rich pageantry of life. |
#5
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conduction
On Thu, 03 Jun 2021 14:02:23 +0100, williamwright wrote:
If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. Even if the conductors aren't touching, sometimes there's a spark. Another question. Why do I wonder about such things? Bill Only if there is a potential difference over the junction. Two disimilar metals can cause a current (electron) flow depending on the temperature at the join. |
#6
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conduction
williamwright wrote
If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. No it doesnt with the lower currents. Even if the conductors aren't touching, sometimes there's a spark. Only if there is a significant voltage across the gap. Another question. Why do I wonder about such things? Thats just the Alzheimer's, nothing to worry about. |
#7
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conduction
On 03/06/2021 14:02, williamwright wrote:
If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. Even if the conductors aren't touching, sometimes there's a spark. Another question. Why do I wonder about such things? Bill What do you mean by "merely touched"? Once there is any contact force, there is a contact area and assuming the metals are clean, a constriction resistance (which you can look up for yourself). Actually if you bring two copper wires close enough then Van der Waals forces will cause them to be attracted together so if they are flexible enough they will end up in contact. And even if they are not touching, put a potential drop across them and even if the dielectric strength of the air is not exceeded, there will be some quantum tunnelling. There are very few stupid questions. |
#8
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conduction
On 03/06/2021 14:02, williamwright wrote:
Another question. Why do I wonder about such things? Newsgroup alt.twaddle.twaddle beckons. Go for it! |
#9
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Lonely Obnoxious Cantankerous Auto-contradicting Senile Ozzie Troll Alert!
On Fri, 4 Jun 2021 03:37:57 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again: No Hahahahahaaa!!! Auto-contradicting senile idiot! -- Kerr-Mudd,John addressing the auto-contradicting senile cretin: "Auto-contradictor Rod is back! (in the KF)" MID: |
#10
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conduction
On 03/06/2021 14:52, John Rumm wrote:
On 03/06/2021 14:02, williamwright wrote: If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. In metals there are usually an abundance of free electrons - these are very easy to separate from the atom which they orbit, and move to another one close by. Hence any conductive atom in close proximity can share its electrons, and allow a current to flow. Even if the conductors aren't touching, sometimes there's a spark. Air is an insulator, but it has a breakdown voltage (aka "dielectric strength") where given enough voltage or "electrical field strength" you can rip electrons from the atoms, even though they are not usually "free". The insulator is then said to have become "ionised" and will become conductive at least while the material remains ionised. The point at which this happens is an intrinsic property of the material, but it's also a function of distance distance. For air you need a voltage difference of around 3kV/mm to cause a breakdown. o to get a spark to jump a metre you need a megavolt, but only 300V for a tenth of a mm and so on. Another question. Why do I wonder about such things? Because you are a bright spark ? Thanks John. A good answer. Bill |
#11
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conduction
On 03/06/2021 15:04, Adam Funk wrote:
On 2021-06-03, williamwright wrote: If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. Even if the conductors aren't touching, sometimes there's a spark. Another question. Why do I wonder about such things? It is all part of the rich pageantry of life. Do you mean the phantasmagoria? Bill |
#12
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conduction
On 03/06/2021 18:37, Rod Speed wrote:
williamwright wrote If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. No it doesnt with the lower currents. Even if the conductors aren't touching, sometimes there's a spark. Only if there is a significant voltage across the gap. Another question. Why do I wonder about such things? Thats just the Alzheimer's, nothing to worry about. **** off Rod. Bill |
#13
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conduction
On 03/06/2021 20:07, williamwright wrote:
On 03/06/2021 14:52, John Rumm wrote: On 03/06/2021 14:02, williamwright wrote: If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. In metals there are usually an abundance of free electrons - these are very easy to separate from the atom which they orbit, and move to another one close by. Hence any conductive atom in close proximity can share its electrons, and allow a current to flow. Even if the conductors aren't touching, sometimes there's a spark. Air is an insulator, but it has a breakdown voltage (aka "dielectric strength") where given enough voltage or "electrical field strength" you can rip electrons from the atoms, even though they are not usually "free". The insulator is then said to have become "ionised" and will become conductive at least while the material remains ionised. The point at which this happens is an intrinsic property of the material, but it's also a function of distance distance. For air you need a voltage difference of around 3kV/mm to cause a breakdown. o to get a spark to jump a metre you need a megavolt, but only 300V for a tenth of a mm and so on. Another question. Why do I wonder about such things? Because you are a bright spark ? Thanks John. A good answer. It was if you gloss over the bit where I left out the "three" in front of megavolt :-) -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#14
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conduction
On 03/06/2021 20:12, John Rumm wrote:
On 03/06/2021 20:07, williamwright wrote: On 03/06/2021 14:52, John Rumm wrote: On 03/06/2021 14:02, williamwright wrote: If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. In metals there are usually an abundance of free electrons - these are very easy to separate from the atom which they orbit, and move to another one close by. Hence any conductive atom in close proximity can share its electrons, and allow a current to flow. Even if the conductors aren't touching, sometimes there's a spark. Air is an insulator, but it has a breakdown voltage (aka "dielectric strength") where given enough voltage or "electrical field strength" you can rip electrons from the atoms, even though they are not usually "free". The insulator is then said to have become "ionised" and will become conductive at least while the material remains ionised. The point at which this happens is an intrinsic property of the material, but it's also a function of distance distance. For air you need a voltage difference of around 3kV/mm to cause a breakdown. o to get a spark to jump a metre you need a megavolt, but only 300V for a tenth of a mm and so on. Another question. Why do I wonder about such things? Because you are a bright spark ? Thanks John. A good answer. It was if you gloss over the bit where I left out the "three" in front of megavolt :-) Weren't you assuming a humid atmosphere and sharpish points for the two conductors? :-) |
#15
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senility
On Thu, 3 Jun 2021 20:52:31 +0100, Fredxx, the notorious, troll-feeding,
senile smartass, blathered again: Weren't you assuming a humid atmosphere and sharpish points for the two conductors? :-) Weren't you and will you not ALWAYS be a notorious smartass, dumb senile Freddie, you demented old troll lover? BG |
#16
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conduction
On Thu, 3 Jun 2021 14:02:23 +0100, williamwright
wrote: If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. Even if the conductors aren't touching, sometimes there's a spark. Another question. Why do I wonder about such things? Bill "ridiculous"? You were once the aerial expert, but now you've sunk to nutter status in my eyes. By all means wonder, but please research before posting here. -- Dave W |
#17
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senility
On Thu, 3 Jun 2021 22:32:39 +0200, Peeler
wrote: On Thu, 3 Jun 2021 20:52:31 +0100, Fredxx, the notorious, troll-feeding, senile smartass, blathered again: Weren't you assuming a humid atmosphere and sharpish points for the two conductors? :-) Weren't you and will you not ALWAYS be a notorious smartass, dumb senile Freddie, you demented old troll lover? BG I wonder if he will be able to get his tongue back out? Cheers, T i m |
#18
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senility
On 03/06/2021 22:26, T i m wrote:
On Thu, 3 Jun 2021 22:32:39 +0200, Peeler wrote: On Thu, 3 Jun 2021 20:52:31 +0100, Fredxx, the notorious, troll-feeding, senile smartass, blathered again: Weren't you assuming a humid atmosphere and sharpish points for the two conductors? :-) Weren't you and will you not ALWAYS be a notorious smartass, dumb senile Freddie, you demented old troll lover? BG I wonder if he will be able to get his tongue back out? Cheers, T i m You must be the only one who responds to Peeler. Or were you simply replying to your own sock? |
#19
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Professional Smartass Alert! LOL
On Thu, 3 Jun 2021 22:30:45 +0100, Fredxx, the notorious, troll-feeding,
senile smartass, blathered again: Weren't you and will you not ALWAYS be a notorious smartass, dumb senile Freddie, you demented old troll lover? BG I wonder if he will be able to get his tongue back out? Cheers, T i m You must be the only one who responds to Peeler. Or were you simply replying to your own sock? Oh, my! So much wisdom in one senile head, poor smartass! G |
#20
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conduction
"williamwright" wrote in message ... On 03/06/2021 18:37, Rod Speed wrote: williamwright wrote If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. No it doesnt with the lower currents. Even if the conductors aren't touching, sometimes there's a spark. Only if there is a significant voltage across the gap. Another question. Why do I wonder about such things? Thats just the Alzheimer's, nothing to worry about. **** off Rod. Go and **** yourself, billy boy. |
#21
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More Heavy Trolling by the Nym-Shifting Senile Australian Pest!
On Fri, 4 Jun 2021 08:53:10 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again: FLUSH the trolling senile asshole's latest troll**** unread -- Bod addressing abnormal senile quarreller Rot: "Do you practice arguing with yourself in an empty room?" MID: |
#22
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conduction
Because you are inquisitive. There is of course an electrostatic field
around a conductor and the air is not really a great insulator and can break down and the two different potentials want to be connected. I see no real quandary. However Superconductors are a different thing altogether. They somehow can join together in such a way that resistance is just not there at all, so unless you take energy ot of a system by magnetic loads etc, if you connect the wire into a loop current will flow all the time until the leakage reduces the voltage. However its not terribly efficient as the power to keep it cold enough is quite great. I do not see how you can have a superconductor at much above absolute zero, ie the temperature where any attempt to cool it cannot happen as there is nothing colder. I'd imagine that the Brownian motion in materials at room temperatures is where resistance comes from, since otherwise you would not get noise in valves and transistors. Brian -- This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please Note this Signature is meaningless.! "williamwright" wrote in message ... If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. Even if the conductors aren't touching, sometimes there's a spark. Another question. Why do I wonder about such things? Bill |
#24
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conduction
And what about static electricity, an issue I've had issues from lately as
may here know. It is after all the basis of vander graph generators and windshurst machines, both of which I've built with varying success. Obviously its those ion imbalances again, but why should friction be the catalyst? We have all had vinyl records charge up merely by the stylus move through the groove, indeed on one cartridge it actually tended to flash over tto a screw at times from the record, or when cassettes are run very fast there are sparks from the hub to the metal spindle of that hub. Brian -- This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please Note this Signature is meaningless.! "williamwright" wrote in message ... On 03/06/2021 14:52, John Rumm wrote: On 03/06/2021 14:02, williamwright wrote: If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. In metals there are usually an abundance of free electrons - these are very easy to separate from the atom which they orbit, and move to another one close by. Hence any conductive atom in close proximity can share its electrons, and allow a current to flow. Even if the conductors aren't touching, sometimes there's a spark. Air is an insulator, but it has a breakdown voltage (aka "dielectric strength") where given enough voltage or "electrical field strength" you can rip electrons from the atoms, even though they are not usually "free". The insulator is then said to have become "ionised" and will become conductive at least while the material remains ionised. The point at which this happens is an intrinsic property of the material, but it's also a function of distance distance. For air you need a voltage difference of around 3kV/mm to cause a breakdown. o to get a spark to jump a metre you need a megavolt, but only 300V for a tenth of a mm and so on. Another question. Why do I wonder about such things? Because you are a bright spark ? Thanks John. A good answer. Bill |
#25
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conduction
On 03/06/2021 20:12, John Rumm wrote:
Thanks John. A good answer. It was if you gloss over the bit where I left out the "three" in front of megavolt :-) A mere bagatelle sir. Bill |
#26
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conduction
On 04/06/2021 07:52, Brian Gaff (Sofa) wrote:
And what about static electricity Well that's going nowhere. Bill |
#27
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conduction
On 03/06/2021 23:53, Rod Speed wrote:
Thats just the Alzheimer's, nothing to worry about. **** off Rod. Go and **** yourself, billy boy. If only I could. Bill |
#28
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conduction
On 03/06/2021 21:51, Dave W wrote:
On Thu, 3 Jun 2021 14:02:23 +0100, williamwright wrote: If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. Even if the conductors aren't touching, sometimes there's a spark. Another question. Why do I wonder about such things? Bill "ridiculous"? You were once the aerial expert, but now you've sunk to nutter status in my eyes. By all means wonder, but please research before posting here. Clearly you have a very shuttered mind. Bill |
#29
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conduction
On 2021-06-03, williamwright wrote:
On 03/06/2021 15:04, Adam Funk wrote: On 2021-06-03, williamwright wrote: If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. Even if the conductors aren't touching, sometimes there's a spark. Another question. Why do I wonder about such things? It is all part of the rich pageantry of life. Do you mean the phantasmagoria? Oops, it's supposed to be "all part of life's rich pageant" (from _A Shot in the Dark_). |
#30
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conduction
On 03/06/2021 14:02, williamwright wrote:
If two conductors are merely touched together electricity can flow between them. That just seems too easy somehow. I mean, just touching? That's ridiculous. I've always thought that it ought to need more intimate bonding between conductors for current to flow. Even if the conductors aren't touching, sometimes there's a spark. Another question. Why do I wonder about such things? Bill Maybe because you have an enquiring mind, most people just accept the facts. |
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