Which way does curent flow?

[blackhj]

To be honest I'm feeling a little bored and need to win a bet! So I thought I'd try and stir up a hornets nest! Do most people on this site use Conventional flow or Electron flow? Does it matter? If one is used over the other why? The right answers here could earn me a slab ( carton or box depending on where you are from), that I'd be happy to share if your near by! Have fun with it and lets see if we can't learn somethig while we are at it. Cheers, Richard.

[mickyd555]

current flow is not electron flow.............so it isnt the same.


the question says current flow, so its + to -


save me a 6 pack

[-Scott-]

Convention is to use "Conventional Current" - flowing from +ve to -ve. This was "set" before it was discovered that it's actually -ve charge carrying (the bulk of the) current, and not +ve charge.

I read recently that there is a country somewhere which uses electron flow by default - just to be different?

Scott

[muzza_fattire]

actually -ve charge carrying (the bulk of the) current

If electrons only carry the bulk of the energy, what is carrying the rest?

[Heathx4]

Current is the flow of electrons! Current flows from -ve to +ve. Holes appear to move from +ve to -ve, but that's only because the electrons are moving from hole to hole from -ve to +ve. But by convention, we take conventional current as flowing from +ve to -ve and it works fine. In other words, the direction of flow of current doesn't really mean much at all. As long as you are consistent with your calculations, you can take it either way. In fact, when you look at the way the electrons move, even describing it as a flow and giving it a direction is a bit of a simplification.

[-Scott-]

actually -ve charge carrying (the bulk of the) current

If electrons only carry the bulk of the energy, what is carrying the rest?

It depends on the material carrying the current, and what you want to believe.

In a silicon based semi-conductor it is only electrons carrying current, as Heath noted.
In a metallic conductor the positive metallic ions are claimed to travel too - albeit very slowly, and I think the "boffins" are starting to question the whole "electromigration" theory.
In a liquid or a plasma, ions of both charges will carry current in opposite directions.

For the purposes of this discussion, on a 4wd Bulletin Board, I was being obsessive...

Cheers,

Scott

[Ralf the RR]

Jeez, the hard questions!

From memory (a long time ago), Conventional current is used in the elctronic sector.
From memory (again) Norton & Therverton (sp) equivalent circuits don't work with Electron flow (I'm sure someone will correct me if I'm wrong).

Going back to me high school physics, I think there is electron flow but, that is the drift speed of electrons, which is very very slow.

Actually, I don't remember much, so this post is probably useless.

[blackhj]

Thanks for all the post guys! It's an interesting read if nothing else. Unfortunately for me, my mate has taken the stance that the bet will be decided on the poll results, despite the vast majority of actual posts defending my position. Oh well it's only beer and I will help him drink it, assuming the poll doesn't swing around again. Having taken the dangerous position of thinking I already new the answer to this question before I asked it, I will say I have learnt some things and come across some new ideas. Thanks again for sharing your thoughts and ideas on a topic that really doesn't matter and has no relavence even if it is fun and kinda interesting. There is still a few days left so vote hard and strong for -ve to +ve so we can deny this rotory driver any beer. Thanks, Richard.

[-Scott-]

Going back to me high school physics, I think there is electron flow but, that is the drift speed of electrons, which is very very slow.

Yep - electron flow is very slow - something like one cm in 100 seconds? But electro-motive force travels at close to the speed of light!

Actually, I don't remember much, so this post is probably useless.

It rarely stops me.

Scott

[Ralf the RR]

Actually, I don't remember much, so this post is probably useless.

It rarely stops me.

Scott

And guess what, it didn't stop me either.

[hj 45]

This depends on where you come from, Yanks say current flow is from negative to positive, because they work on the electron flow, while we say that current runs positive to negative- the opposite to current flow. So there you go.

[Mick_n_Sal]

For the purpoe of your bet - when fault finding in the truck, I use conventional flow +ve to -ve.

At work the point is moot - I work with AC mostly.

[MAVRK-4]

I agree 100% with Heathx4's explanation..... but technically it comes down to the definition of 'Current flow'

[HeathGQ]

it flows -----> that way

["CANADA"]

no im pretty sure its <------ that way

[bradley]

[quote="NJ SWB
It depends on the material carrying the current, and what you want to believe.

In a silicon based semi-conductor it is only electrons carrying current, as Heath noted.
In a metallic conductor the positive metallic ions are claimed to travel too - albeit very slowly, and I think the "boffins" are starting to question the whole "electromigration" theory.
In a liquid or a plasma, ions of both charges will carry current in opposite directions.

For the purposes of this discussion, on a 4wd Bulletin Board, I was being obsessive...

Cheers,

Scott[/quote]

Yeah last engineering studies i did, the jury was still out on weather it was actually electons or ions moving etc.

But more importantly, does the gas go from the beer to the air or air to beer ?????

["CANADA"]

beer to mouth

[HeathGQ]

no im pretty sure its <------ that way

that just cracked me up big time

[bradley]

beer to mouth

and from the 'tailpipe' back to the atmosphere from where it came

[DR Frankenstine]

Here's a thought.

Ex 1. Batt + ----wire------->l--------wire-------Light --------batt neg

will the light illuminate YES


Ex 2. Batt neg-------wire------>l-------wire------Light---------Batt +

Will the light illuminate NO


I would say that current flows from + to neg

[Bluey]

Here's a thought.

Ex 1. Batt + ----wire------->l--------wire-------Light --------batt neg

will the light illuminate YES


Ex 2. Batt neg-------wire------>l-------wire------Light---------Batt +

Will the light illuminate NO


I would say that current flows from + to neg

unless i'm more tired than i think and reading this wrong, then both will light. a light (filament) doesnt care what polarity is connected to each end of the lamp, just as long as there is sufficient voltage difference (potential) between the two. case in point is toyota headlights, which have 12v on one side, and switch on gnd to other side to light up.

[GRIMACE]

Here's a thought.

Ex 1. Batt + ----wire------->l--------wire-------Light --------batt neg

will the light illuminate YES


Ex 2. Batt neg-------wire------>l-------wire------Light---------Batt +

Will the light illuminate NO


I would say that current flows from + to neg

unless i'm more tired than i think and reading this wrong, then both will light. a light (filament) doesnt care what polarity is connected to each end of the lamp, just as long as there is sufficient voltage difference (potential) between the two. case in point is toyota headlights, which have 12v on one side, and switch on gnd to other side to light up.

DITTO

[Heathx4]

Here's a thought.

Ex 1. Batt + ----wire------->l--------wire-------Light --------batt neg

will the light illuminate YES


Ex 2. Batt neg-------wire------>l-------wire------Light---------Batt +

Will the light illuminate NO


I would say that current flows from + to neg

unless i'm more tired than i think and reading this wrong, then both will light. a light (filament) doesnt care what polarity is connected to each end of the lamp, just as long as there is sufficient voltage difference (potential) between the two. case in point is toyota headlights, which have 12v on one side, and switch on gnd to other side to light up.

My guess is that the >| between the wires is a diode. Diodes only let current flow one way through them (actually, that's a gross simplification but will do for our purposes). When you draw a circuit schematic, diodes are drawn with an arrow pointing towards a perpendicular line. The way I remember it (which is due to my background in semiconductors) is to think of the arrow indicating that if electrons were to flow in that direction, they would be blocked by the line. Another way to think of it is that the arrow points in the direction that conventional current is allowed to flow.

This page has some handy diagrams which describe this:
http://www.allaboutcircuits.com/vol_3/chpt_3/1.html

In any case, the good Dr's diagrams don't prove anything. Circuit diagram symbols are invented and then used by convention - they don't need to represent anything in the physical world at all.