Conventional Current and Electron Flow effect on schematics and actual circuits - Page 1
Forum section: electronics / beginners

author: IVLRNR
author_rank: Contributor
timestamp: January 13, 2021, 10:25:57 am
content: Hi All,Sorry for beginner questions:Lots of books and diagrams show conventional flow as opposed to electron flow. Isn't it the case that in most real circuits say DC, that if on the one hand I have the books showing current flowing from the positive terminal of the Battery to the anode then out the cathode, then back to the supply? How can this diagram be done in real life? I mean + anode ------> cathode -, and same when reverse biased + cathode <------ anode -?I just don't seem to understand how it can work? based on supposed as opposed to real electron flow, if you have it hooked up with the idea of conventional current? and this is not how the circuit works in truth, how can the circuit work at all? I have googled a bit, and been over the concepts, and will do more, but my mind is becoming jelly over this issue, any help would be great.Also, as a freebie, I have googled heaps on this matter, because just found out a fluke meter I thought I bought was an 87v is actually and 83v, still does most stuff the same and it was cheaper (a bit, no enough) than the 87v I bought, but I am thinking it will still do most to near everything I need. Wondering if anyone else has an 83v and what their experience with it is, I am stuck with it now, due to time held, but I am hoping it isn't all that bad?Any advice would be greatly appreciated.

author: SVFeingold
author_rank: Frequent Contributor
timestamp: January 13, 2021, 11:11:10 am
content: Quote from: IVLRNR on January 13, 2021, 10:25:57 amThis is normal. I think the general wisdom is to completely ignore real electron flow and just pretend that conventional is correct. All the math works out, and it's what the entire world does. A long, long time ago someone used a "plus" when they should have a "minus" and next thing you know, here we are today with a backwards notation. Hey he had a 50/50 shot...and he guessed wrong. C'est la vie. Fortunately everything works the same, just with the signs flipped from the "real" system. Just go with it. You are in for a very bad time if you try to "rebuild" every circuit in your mind as one with real electron flow instead of conventional. It simply doesn't matter unless you're doing it out of pure intellectual curiosity.If one day you start designing semiconductor devices, that's probably the time to worry about it. Until then...As for the Fluke, the 83V is a fine meter and should do everything you need for quite some time. Once you find you have a specific need that it can't meet, that's the time to start shopping around again.

author: radiolistener
author_rank: Super Contributor
timestamp: January 13, 2021, 11:14:41 am
content: Quote from: IVLRNR on January 13, 2021, 10:25:57 amit doesn't matter. If you look fromelectronpoint of view, they are flowing from - terminal to + terminal. But if you look fromelectron holepoint of view, they are flowing from + terminal to - terminal. You're looking at the same process from different point of view and see different directionThe Earth is moving around the Sun. And the Sun is moving around the Earth. Both are correct, just different point of view on the same process...

author: Ian.M
author_rank: Super Contributor
timestamp: January 13, 2021, 11:28:12 am
content: Benjamin Franklinguessed wrong, and due to 268 years of scientific and industrial inertia using his best guess at the time, we are stuck with so called 'conventional current flow' and a notional positive charge carrier. In most cases the polarity of the charge carrier doesn't matter as long as it remains consistent for the whole circuit, so you only have to consider electron current when dealing with the detailed physics of current flow inside semiconductors, vacuum tubes, and ionised gasses, and in electrochemistry.

author: retiredfeline
author_rank: Frequent Contributor
timestamp: January 13, 2021, 11:36:24 am
content: Move to the anti-universe.

author: CaptDon
author_rank: Super Contributor
timestamp: January 13, 2021, 01:54:42 pm
content: Don't get too concerned. What do you mean how can it work at all? We still draw all symbols as if current flows from + to -. We know in reality the electrons move from - to + or emitted from cathode to land at the anode. So what, who cares? People pray to deities that can't be proven to exist. At least we can prove electron flow. Maybe you can now solve the mystery of high voltage D.C. power transmission? If we put one polarity up on the towers theory suggests the cabling will attract all ions, dust, dirt and everything in its path, and the same theory suggests if we use the other polarity on the towers the cabling will lose metallic ions and eventually disintegrate. Should the hull of my metallic boat be slightly positive or slightly negative referenced to the lake? Good luck.

author: rstofer
author_rank: Super Contributor
timestamp: January 13, 2021, 04:26:21 pm
content: AFAICT, the US Navy still teaches electron flow and they turn out some excellent ETs. It just doesn't matter but every class I ever took dealt with current flow. It just seems more intuitive to think of a current as coming out of the + terminal of a battery and flowing around the circuit before reentering at the - terminal.I like current flow in the direction of the arrow on transistors and diodes but, again, either works. It just depends on what is expected where you attend school or work for a living.A most excellent ET program is the US Navy NEETS curriculum:http://www.compatt.com/Tutorials/NEETS/NEETS.html

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: January 13, 2021, 05:10:41 pm
content: This is all presupposing that electrons are little particles whizzing around. That's a convenient model for our macroscopic world but hardly a more realistic description based on what we know of quantum mechanics etc. How would we describe how electrical circuits behave using the idea that electrons are waves, rather than particles? What, if anything, would be moving? If we try to explain everything as precisely as the modern state of science permits, we'd get very little done in our macroscopic world.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 13, 2021, 07:14:22 pm
content: https://xkcd.com/567/

author: IVLRNR
author_rank: Contributor
timestamp: January 14, 2021, 01:04:19 am
content: Yeah. The concepts relating to waves is beyond me at the moment! But it is nice to know there is some head bending available in the future, as deep down the rabbit hole, and further, than I perhaps want to go.

author: SilverSolder
author_rank: Super Contributor
timestamp: January 14, 2021, 03:00:10 am
content: Tube circuits may make a little more sense when thinking in terms of the "real" current flow. But other than that... might as well "go with the flow"!

author: sibeen
author_rank: Frequent Contributor
timestamp: January 14, 2021, 05:04:21 am
content: Quote from: rstofer on January 13, 2021, 04:26:21 pmBy some strange quirk the Anglo militaries teach electron flow. I started out as an apprentice tech in the Australian Army many, many moons ago and it was all electron flow.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: January 14, 2021, 05:05:30 am
content: As pointed out in the prior posts it doesn't really matter. We can be sure that neither model is used by these atomic scale particles as they decide which way to wiggle and flow. Conventional current flow is useful when interpreting schematics with diodes and transistors because you can just follow the arrows. But thinking about electrons is better when understanding how CRTs and vacuum tubes work. It also tends to help if you are trying to follow the chemistry in batteries. It is however very, very important to use the same model throughout your evaluation of a particular problem. And this is harder if you don't pick one or another and stick with it. But even this strategy doesn't work because as you go through different classes and jobs you will find that the people running the show have their own preference and you will have to deal with their desires. So whichever you pick as your favorite, make sure that you understand and can use the other and recognize what has to change as you swap back and forth.