why does 'conventional flow' still exists?

steveb

Joined Jul 3, 2008
2,436
Why do I always seem to be the one tasked with asking the akward question?



How many electrons have you seen passing through a capacitor, on their way from -ve to +ve?
I've seen a couple blasting their way through an exploding electrolytic capacitor. They were disobeying the one-way sign, - crazy little devils. :p
 

Wendy

Joined Mar 24, 2008
23,415
As Steve said, I don't have to see it, but I'd better know which is which.

As for seeing it, every day at work, about 1000 or more times a day. Look up EFO and negative EFO.
 

Thread Starter

drk

Joined Mar 8, 2008
41
to steveb:
it would make some confusion in the beginning sure, but i would see it as an investment to the future. ok, some confusion here, but after that we wouldn't be living with two contradicting definitions.
but i guess no one wants the trouble.
 

dmccormick84

Joined Mar 3, 2010
11
Russ... Maxwell was way back in the nineteenth century and he was not an electronic dude, he was in physics. When I learned electronics from Uncle Sam's Air Force in 1957, we were taught electron flow... later on when semiconductors got rolling, I learned 'hole flow'. Ya know what? Makes no danged difference... NONE! Take the one you like and run with it.
(BTW... some explanation... transistors were too delicate in the '50s for guided missiles, I worked on the Hughes Aircraft Falcon... it had teeny tiny tubes (valves) as active devices!! ):)
 

russ_hensel

Joined Jan 11, 2009
825
Physics is the science which underlies the more mundane engineering task of electronics. The guys who formulate the theories of semiconductors know a lot of physics and you can bet they use the physics form of the equations. Maxwell may have been way back in the 19th century, but equations are still the basis for classical understanding of the electric and magnetic field, radio waves, light..... Things that are more accurate are substantially more complicated and are extensions for quantum mechanics.
 

steveb

Joined Jul 3, 2008
2,436
... but after that we wouldn't be living with two contradicting definitions...
I think you are misunderstanding the explanations. It's not really that they are contradicting definitions, they are just different definitions. Just about everyone agrees that it is unfortunate that Ben Franklin guessed wrong. I've yet to meet a person that won't acknowledge this, whether they are beginning students, or physics professors. If we could do a reboot, we would surely opt to label the electron as having a positive charge. This would make our definition of the direction of positive conventional current match our definition of the direction of positive electron flow.

Note that there is nothing in the definition of conventional current that contradicts anything. The real issue is which particles we label as having a negative charge. The labeling of the electron as a negative charge is just a little less convenient because it is the most usual charge carrier that we talk about in practical situations. Note that, even if we call the electron a positive charge, and change all physical laws to be consistent with this, the definition of conventional current would remain the same. Positive current would still be either positive charge moving in the positive direction, or negative charge moving in the negative direction. The only things that would change are the label we put on the electron charge, and the fact that positive conventional current direction then aligns with positive electron flow direction.

However, the idea of changing now is just not sensible. There is too little benefit and too much harm that would be done. I'm talking real harm, not just inconvenience. Mistakes in critical calculations in engineering could result it deaths for example. Then there are monetary costs, changing software and rewriting books and manuals. (Not to mention the inevitable nerd-gangs rioting in the streets ;) ) It's much safer and less costly to keep things as they are.

No matter how you slice it, you have to train your mind to get used to many nonintuitive concepts when learning physics, and this issue of getting used to various established definitions is one of the easier ones. - Just bite the bullet, and soon you will be healing.
 
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Wendy

Joined Mar 24, 2008
23,415
Preach on Brother Steve!

I think this is much ado about nothing, people act like it is a burning issue, it's not. It is simply a matter of understanding, then moving on.

Way back when I choose to stick with electron flow. Electronic symbols are pretty arbitrary, I always think of the arrow pointing to the negative side. I understand conventional is out there, but other than that I don't think of it at all.
 

retched

Joined Dec 5, 2009
5,207
You can go your entire EE career, being successful following only conventional current theory.

You can go your entire EE career, being successful following only electron flow theory.

Do you like cream in your coffee or not?

If you prefer one over the other, use it. Live and let live.
 
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