Anonymous-0
Well-known Member
I say it can't be classified because it's not a current, just one big splash of electricity. My friend says it's gotta be AC or DC and wants to know which it is. Thanks!
It's not 'current' you say.. but it is 'electricity'.. Good one!
DC current does not change direction.. IE.. electrons flow to the positive charg.. alternating current, the polarity swaps back and forth.
While both can be made to jump an arc gap ( air gap ).. my bet is on DC..
Whatcha think electricity is.. perhaps? motive electons maybee?
google Static electricity.
soundguy
DC current does not change direction.. IE.. electrons flow to the positive charg.. alternating current, the polarity swaps back and forth.
While both can be made to jump an arc gap ( air gap ).. my bet is on DC..
Whatcha think electricity is.. perhaps? motive electons maybee?
google Static electricity.
soundguy
buickanddeere
Well-known Member
Static electricity is DC.
With lightening sometimes a downward leader is mentioned. Then an up strike or up stroke?
In any case it's a bunch of electrons getting gradually torn away and deposited somewhere else. They eventually make the jump to get "home" all in one split second.
With lightening sometimes a downward leader is mentioned. Then an up strike or up stroke?
In any case it's a bunch of electrons getting gradually torn away and deposited somewhere else. They eventually make the jump to get "home" all in one split second.
ScottyHOMeY
Well-known Member
It's definitely a current.
I did a little googlin' and found that most lightning is a negative charge in a cloud discharging to ground, and that a typical bolt will carry about 40kA, that's 40,000 amps, at a voltage up to 3 million volts per meter of length of the lightning bolt (i.e., one gigavolt for every 1000 feet). That qualifies as current in my book.
Couldn't find anything in a quick search that answers your AC/DC queston directly, but I favor DC. There's no changing of polarity in a cloud like an alternator puts out. It's straight discharge, whether the typical negative type (cloud to ground) or positive (ground to cloud).
Ain't it nice that lightning is positive ground?
I did a little googlin' and found that most lightning is a negative charge in a cloud discharging to ground, and that a typical bolt will carry about 40kA, that's 40,000 amps, at a voltage up to 3 million volts per meter of length of the lightning bolt (i.e., one gigavolt for every 1000 feet). That qualifies as current in my book.
Couldn't find anything in a quick search that answers your AC/DC queston directly, but I favor DC. There's no changing of polarity in a cloud like an alternator puts out. It's straight discharge, whether the typical negative type (cloud to ground) or positive (ground to cloud).
Ain't it nice that lightning is positive ground?
Walt Davies
Well-known Member
Kind of depends on what kind of tractor you are riding on at the time doesn't it. An Ac or Case DC should make quite a difference when it strikes you.
Walt
Walt
Anonymous-0
Well-known Member
Jim H SW-PA
Member
Definitely DC [directed current
moonlite 37
Member
It is not a current but a charge.
By strict defintion of the terms, lightning is neither.
Direct current is - by defintion - current in one direction, period.
Alternating current is a term that was created to desribe planned and consistent variating current - i.e. "cycles."
Lighting is a mass of "direct type currents" going every which way, and is scientifically referred to as something like "unidirectional" or "mutidirectional" current.
Direct current is - by defintion - current in one direction, period.
Alternating current is a term that was created to desribe planned and consistent variating current - i.e. "cycles."
Lighting is a mass of "direct type currents" going every which way, and is scientifically referred to as something like "unidirectional" or "mutidirectional" current.
Anonymous-0
Well-known Member
I didn't like it either
Anonymous-0
Well-known Member
No, did not like it either, just missed me as a kid, had just found a lawn jart and was checking out how they work, never saw one before, was tossing it around in one of our pens, kind of convienent to have one of those in your hand then have your hair stand up, I remembered to hit the deck, did so instantly, not sure where it hit, but it was the loudest thing I'd ever heard. Glad I had longer hair then and learned what to do if it ever happened, was just like that static thing you touch and makes your hair stand up.
Anonymous-0
Well-known Member
Its DC, look back to Franklin's original experiments. He charged a Leyden jar (capacitor) from a lightning bolt. If it was AC, he would have said Don't tase me, bro!
dave guest
Well-known Member
Maybe pulsating DC. Like a little bit of both. Must be a science professor out there or don't they like tractors?
MarkB_MI
Well-known Member
- Location
- Motown USA
An engineer would describe lightning as an impulse. An impulse theoretically has infinite magnitude but zero duration. You can only have a true impulse in mathematical terms, but a lightning bolt is close enough. One of the characteristics of an impulse is that it contains all frequencies from zero to infinity. That's why lightning interferes with radios (particularly AM radios that operate at low frequencies): the impulse generates rf energy across all broadcast bands.
Now, technically, lightning does not alternate: it travels in one direction only. But the rapid change of current is effectively high frequency because it has a very high rate of change.
Now, technically, lightning does not alternate: it travels in one direction only. But the rapid change of current is effectively high frequency because it has a very high rate of change.
Anonymous-0
Well-known Member
My take:
Lightning is the dissipation of charged particles (ion and electron) built up in the atmosphere. When electrons are separated from their atoms by some means (chemical, friction, photoelectric, electromagnetic or some other way) an electrostatic charge exists on the atoms from which the electrons were removed (positive) and the electrons themselves (negative). When these separated charges accumulate together to build up enough emf (voltage) to ionize the air, or whatever is between them and an oppositely charged accumulation, an arc of electrical current occurs allowing the ions and electrons to recombine and the charge is nullified. The energy dissipated in the arc, in the form of heat, light and radio waves, is the energy originally built up (in the case of lightning) by violent friction in the atmospheric currents that caused the ionization in the first place. What may not be so obvious is that the charge 'that made your hair stand up' is between an atmospheric 'cloud' of charges and the earth, itself, which has the same charge as you, since you are standing on it. The object on the earth that offers the best ionization path between the two charges will be 'struck' if and when the voltage potential reaches the ionization point. And, it probably makes little difference if you are on your tractor with rubber tires unless it has a metal cab surrounding you. Lightning is the gorrilla in the electrical world!
Tall AM radio towers have guy wires with insulators spaced at intervals between the tower & earth. Often when a thunderstorm is building up, there is periodic arcing across the insulators (all at once in each guy) due to the build up of charges in the atmosphere around the wires with respect to earth. They discharge with loud cracks and simultaneous blue arcs across the insulators, even though there may not be any lightning strikes taking place nearby.
Be aware of where you are when a thunderstorm threatens, you may not get any warning before becoming a part of an arc path!
Is lightning AC or DC? The arc evidently has components of both, but it started out as DC.
Lightning is the dissipation of charged particles (ion and electron) built up in the atmosphere. When electrons are separated from their atoms by some means (chemical, friction, photoelectric, electromagnetic or some other way) an electrostatic charge exists on the atoms from which the electrons were removed (positive) and the electrons themselves (negative). When these separated charges accumulate together to build up enough emf (voltage) to ionize the air, or whatever is between them and an oppositely charged accumulation, an arc of electrical current occurs allowing the ions and electrons to recombine and the charge is nullified. The energy dissipated in the arc, in the form of heat, light and radio waves, is the energy originally built up (in the case of lightning) by violent friction in the atmospheric currents that caused the ionization in the first place. What may not be so obvious is that the charge 'that made your hair stand up' is between an atmospheric 'cloud' of charges and the earth, itself, which has the same charge as you, since you are standing on it. The object on the earth that offers the best ionization path between the two charges will be 'struck' if and when the voltage potential reaches the ionization point. And, it probably makes little difference if you are on your tractor with rubber tires unless it has a metal cab surrounding you. Lightning is the gorrilla in the electrical world!
Tall AM radio towers have guy wires with insulators spaced at intervals between the tower & earth. Often when a thunderstorm is building up, there is periodic arcing across the insulators (all at once in each guy) due to the build up of charges in the atmosphere around the wires with respect to earth. They discharge with loud cracks and simultaneous blue arcs across the insulators, even though there may not be any lightning strikes taking place nearby.
Be aware of where you are when a thunderstorm threatens, you may not get any warning before becoming a part of an arc path!
Is lightning AC or DC? The arc evidently has components of both, but it started out as DC.
Since one of my previous job responsibilities was figuring out how to protect aircraft from the effects of lightning, I have a pretty good idea of what happens.
Lightning is best described as "pulsed DC". The leader that initially establishes the discharge path is, in simple terms, a static charge which has reached sufficient potential to ionize a path through the air. This ionized path is what eventually carries the actual lighting discharge. There is very little current associated with the leader, and as far as how lightning affects people, buildings, etc., the leader can be ignored.
Once an ionized path is established, the part of the discharge that we see (and that creates thunder) occurs. This is an initial high current pulse, called the first return stroke, which may reach 100,000 amperes in a severe strike. This current decays rapidly (on the order of milliseconds)to a much lower level. Most of the actual charge transfer occurs during this longer lower level discharge, which is limited by how fast the charge can move to replace what was originally discharged. If 100,000 amperes isn't current, I don't know what is!!!
Sometimes the initial discharge is followed by repeated discharges when enough charge flows into the vicinity of the ionized path before the path dissipates, and creates a second (or third, or fourth, etc.) flash. This phenomenon is why lightning sometimes appears to flicker - it really is a series of discharges.
In a single strike, current only flows in one direction. Cloud-to-ground strikes generally originate in a pocket of negative charge in the cloud, i.e., the cloud is negative with respect to the earth. Cloud-to-ground strikes can also originate in a positively charged area of a cloud, in which case the earth is negative with respect to the cloud. A positive charge is simply a lack of electrons, a negative charge is a surplus of electrons. In a cloud-to-cloud strike, the leader can initiate in either a positive or negative pocket of charge.
I've attached a link to a NASA website with a good discussion of lightning.
To answer the original question, yes, lightning is in fact a very large pulse of electrical current. Any individual strike is DC, as charge only moves in one direction. A single lightning strike may contain multiple discharges, but they will all be of the same polarity. Other strikes may be the opposite polarity, but the polarity does not change during an individual discharge.
Keith
Marshall Space Flight Center lightning primer
Lightning is best described as "pulsed DC". The leader that initially establishes the discharge path is, in simple terms, a static charge which has reached sufficient potential to ionize a path through the air. This ionized path is what eventually carries the actual lighting discharge. There is very little current associated with the leader, and as far as how lightning affects people, buildings, etc., the leader can be ignored.
Once an ionized path is established, the part of the discharge that we see (and that creates thunder) occurs. This is an initial high current pulse, called the first return stroke, which may reach 100,000 amperes in a severe strike. This current decays rapidly (on the order of milliseconds)to a much lower level. Most of the actual charge transfer occurs during this longer lower level discharge, which is limited by how fast the charge can move to replace what was originally discharged. If 100,000 amperes isn't current, I don't know what is!!!
Sometimes the initial discharge is followed by repeated discharges when enough charge flows into the vicinity of the ionized path before the path dissipates, and creates a second (or third, or fourth, etc.) flash. This phenomenon is why lightning sometimes appears to flicker - it really is a series of discharges.
In a single strike, current only flows in one direction. Cloud-to-ground strikes generally originate in a pocket of negative charge in the cloud, i.e., the cloud is negative with respect to the earth. Cloud-to-ground strikes can also originate in a positively charged area of a cloud, in which case the earth is negative with respect to the cloud. A positive charge is simply a lack of electrons, a negative charge is a surplus of electrons. In a cloud-to-cloud strike, the leader can initiate in either a positive or negative pocket of charge.
I've attached a link to a NASA website with a good discussion of lightning.
To answer the original question, yes, lightning is in fact a very large pulse of electrical current. Any individual strike is DC, as charge only moves in one direction. A single lightning strike may contain multiple discharges, but they will all be of the same polarity. Other strikes may be the opposite polarity, but the polarity does not change during an individual discharge.
Keith
Marshall Space Flight Center lightning primer
Anonymous-0
Well-known Member
Not without a "flux capacitor"
G
guido
Guest
In-to-deep
I vote D.C.
If it kicks you like a mule its D.C.
If it A.C. it will not let you go!
Guido.
I vote D.C.
If it kicks you like a mule its D.C.
If it A.C. it will not let you go!
Guido.
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