Series DC Circuit. I hear it described both ways on the internet. Which direction does it flow for you?
Negative to Positive, or Positive to Negative?
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Series DC Circuit. I hear it described both ways on the internet. Which direction does it flow for you?
Pos to neg but in reality a light don't care which way it goes.
It's a matter of conventions.
Chemists will tell you that electrons flow from the anode to the cathode, which is exactly the opposite of what is known as "conventional current."
See http://www.science-campus.com/engineering/electrical/dc_theory/chapter2/dctheory_2_1.html
Chemists will tell you that electrons flow from the anode to the cathode, which is exactly the opposite of what is known as "conventional current."
See http://www.science-campus.com/engineering/electrical/dc_theory/chapter2/dctheory_2_1.html
Originally Posted By: 1000MPH
That lightbulb in the middle isn't going to work with that circuit.
LoL lets assume and hope the person drawing it assumed it was to be through the light bulb not just connected to one side.
That lightbulb in the middle isn't going to work with that circuit.
LoL lets assume and hope the person drawing it assumed it was to be through the light bulb not just connected to one side.
Technically current flows from neg to pos. however at least for automotive work we think in terms of pos to neg. It makes things like schematics simpler.
The flow of electrons is from what we consider the negative voltage to the positive voltage. That said, it is only a sign convention; when analyzing electronics one usually doesn't care, as long as one is consistant in direction. Sum of currents into a node sums to zero; sum of voltage drops sum to zero (assuming nothing nefarious such as electromagnetic radiation).
Want fun? Study semiconductors, where you have to study the flow of carriers; you wind up with two opposing flow of "currents"! Holes go one way, electrons the other. At the same time. I'm not convinced I really understood it when I took it...
What's really fun is reading old electronic schematics, where everything is P type silicon, and drawn upside down relative to how we draw N type silicon today.
Don't get me started on four way ties in schematics... Some things are just wrong!
Want fun? Study semiconductors, where you have to study the flow of carriers; you wind up with two opposing flow of "currents"! Holes go one way, electrons the other. At the same time. I'm not convinced I really understood it when I took it...
What's really fun is reading old electronic schematics, where everything is P type silicon, and drawn upside down relative to how we draw N type silicon today.
Don't get me started on four way ties in schematics... Some things are just wrong!
I'm an electrical engineer. Trust me, this caused some confusion among the first year EE students. We usually use the convention that current flows from a high potential (more positive) to a lower potential (more negative). Ammeters are built to register current this way. As others have said, the electrons are actually going from negative to positive.
Electrons ( - charged) are what flow in the wire and are attracted to a + charge.
The electrons would flow CC in your schematic.
The electrons would flow CC in your schematic.
dont forget the electrons do know what color the wires are. LOL
It is about CONVENTION. Scientists defined positive and negative charges before they discovered electrons, and defined current to go from positive to negative, before discovered it is the electron that moves.
Originally Posted By: bradepb
Technically current flows from neg to pos. however at least for automotive work we think in terms of pos to neg. It makes things like schematics simpler.
Yes, but this is why the negative is always removed from the battery first, and not the positive.
Technically current flows from neg to pos. however at least for automotive work we think in terms of pos to neg. It makes things like schematics simpler.
Yes, but this is why the negative is always removed from the battery first, and not the positive.
Been decades ago but we had to go through electron flow, hole flow, the valence electrons, forbidden band, skin effects, coulomb law, ohms law, magnetic inductions, faraday this & than, then more this and that which is why I don't remember this and that.
I just use a DVM for a few basics and don't want to know anymore.
I just use a DVM for a few basics and don't want to know anymore.
Originally Posted By: KenO
Originally Posted By: bradepb
Technically current flows from neg to pos. however at least for automotive work we think in terms of pos to neg. It makes things like schematics simpler.
Yes, but this is why the negative is always removed from the battery first, and not the positive.
Nope, it's done for safety. Most cars are negative ground, and if you're wrenching on the negative terminal the only thing you have to worry about touching with the wrench is the positive terminal. Touching any other metal part of the car with the wrench is perfectly safe. On a positive ground vehicle, you would remove the positive terminal first.
Originally Posted By: bradepb
Technically current flows from neg to pos. however at least for automotive work we think in terms of pos to neg. It makes things like schematics simpler.
Yes, but this is why the negative is always removed from the battery first, and not the positive.
Nope, it's done for safety. Most cars are negative ground, and if you're wrenching on the negative terminal the only thing you have to worry about touching with the wrench is the positive terminal. Touching any other metal part of the car with the wrench is perfectly safe. On a positive ground vehicle, you would remove the positive terminal first.
Which one is correct?
Conventional current flow considers current to travel in the direction OPPOSITE the flow of electrons.
Hence, supton is correct.
"Conventional current" is one of those things that makes scientists and engineers cringe. It basically comes down to "We know this is wrong, but since everyone's been doing to wrong for 100 years, we're going to keep doing it wrong so as not to confuse people." This approach, of course, immediately confuses people.
Hence, supton is correct.
"Conventional current" is one of those things that makes scientists and engineers cringe. It basically comes down to "We know this is wrong, but since everyone's been doing to wrong for 100 years, we're going to keep doing it wrong so as not to confuse people." This approach, of course, immediately confuses people.
Just have to decide who to confuse. Do we confuse everyone by using electron flow, making the symbols for diodes and transistors inconsistent, or do we confuse engineers and physicists who know the electrons go the other way?
I was taught that current was simply the flow of holes, not electrons, and that has served me well.
I was taught that current was simply the flow of holes, not electrons, and that has served me well.
I found an interesting description:
Quote:
Electron vs. Conventional Theory
While this is not terribly important when troubleshooting electrical problems, understanding the difference can prevent arguments and confusion. Current is the flow of electrons through the wires. Those electrons have a negative charge. When they leave the battery they leave from the negative post, then flow through the negative cable, body, circuitry, and back in on the positive post. That is electron theory and is technically correct.
When one electron moves from one spot to the next, it leaves a space, or "hole" behind where it was. The next electron moves into that hole but it too left a hole behind. In effect, the holes are moving in the opposite direction as the electrons. It's not important to know that but some instructors use that description and it can get confusing. This is conventional theory and is used most often because starting at the positive terminal feels more natural and is easier to follow. With conventional theory, current leaves the battery positive post, flows through the circuitry, then back in the negative post. If someone tries to argue that conventional theory is wrong, simply agree with them, then go back to your understanding. Becoming confused with this minor detail won't help you troubleshoot an electrical problem. It is sufficient to know that there are two different ways of visualizing current flow and most people function just fine without ever obsessing over that difference.
LINK
Comments?
Quote:
Electron vs. Conventional Theory
While this is not terribly important when troubleshooting electrical problems, understanding the difference can prevent arguments and confusion. Current is the flow of electrons through the wires. Those electrons have a negative charge. When they leave the battery they leave from the negative post, then flow through the negative cable, body, circuitry, and back in on the positive post. That is electron theory and is technically correct.
When one electron moves from one spot to the next, it leaves a space, or "hole" behind where it was. The next electron moves into that hole but it too left a hole behind. In effect, the holes are moving in the opposite direction as the electrons. It's not important to know that but some instructors use that description and it can get confusing. This is conventional theory and is used most often because starting at the positive terminal feels more natural and is easier to follow. With conventional theory, current leaves the battery positive post, flows through the circuitry, then back in the negative post. If someone tries to argue that conventional theory is wrong, simply agree with them, then go back to your understanding. Becoming confused with this minor detail won't help you troubleshoot an electrical problem. It is sufficient to know that there are two different ways of visualizing current flow and most people function just fine without ever obsessing over that difference.
LINK
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