Confused - Page 1
Forum section: electronics / beginners

author: bobdabiulder
author_rank: Contributor
timestamp: January 05, 2016, 01:59:13 am
content: To put it simply, the root of my confusion is Thomas Edison.He decided that electricity flows from + to -. Now, when I look at a diode or circuit diagram, I never know if the person is writing it under the assumption that Thomas Edison is right, or if they are basing their info on fact. I get confused looking at diodes, multimeters, etc.Is there any way to remedy this stuff?Thomas!

author: c4757p
author_rank: Super Contributor
timestamp: January 05, 2016, 02:08:37 am
content: Quote from: blueskull on January 05, 2016, 02:03:09 amIf you're not designing actual semiconductor devices, you don't need tocarewhat the polarity of the actual charge carriers is. Just use "conventional current" all the time.

author: bobdabiulder
author_rank: Contributor
timestamp: January 05, 2016, 02:36:24 am
content: Quote from: c4757p on January 05, 2016, 02:08:37 amI should, but some people/Desired itself scientific current, so it's still uniform. I would rather not reverse the polarity of an electrolytic capacitor bc of conflicting "ideals".

author: c4757p
author_rank: Super Contributor
timestamp: January 05, 2016, 02:42:02 am
content: What's an example of a situation where you might mix them up? I've got by for quite a long time by ignoring "electron current", unless I'm trying to think about the internal structure of some semiconductor device.

author: Brumby
author_rank: Unknown
timestamp: January 05, 2016, 02:46:35 am
content: My first thought runs to CRT's and thermionic valves (tubes).

author: rdl
author_rank: Super Contributor
timestamp: January 05, 2016, 02:55:08 am
content: It doesn't matter which is used as long as it's consistent, but conventional current is what's used most commonly.And I think it was actually all Ben Franklin's fault.

author: retrolefty
author_rank: Super Contributor
timestamp: January 05, 2016, 02:56:47 am
content: Quote from: bobdabiulder on January 05, 2016, 01:59:13 amYes it is as much drama as you find in our field.So yes they (not Edison I think) defined current flow + to - before they even understood the atom and it's structure. Later it was understood that electron current flow is - to +. Really doesn't matter as long as you keep to one convention when tracing your schematics. In the U.S. Air Force they taught us electron flow - to + and said to ignore what the EEs and college profs say about so called hole flow, the only thing that moves are electrons. However the EEs and Profs get the last laugh as they still got to define the arrow direction for semiconductor symbols.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 05, 2016, 03:23:12 am
content: people mourn because they got confused. people got confused because they have lack of knowledge.... ymmvhttp://www.mi.mun.ca/users/cchaulk/eltk1100/ivse/ivse.htm

author: jwm_
author_rank: Frequent Contributor
timestamp: January 05, 2016, 03:24:24 am
content: I think part of the confusion is due to thinking that electrons 'flow' at all to a significant degree. People imagine that a bunch of electrons are flowing along like water from negative to positive and that carries the signal. However that is not the case, it is the electronic field that carries the signal.This is fairly easy to see when you consider the speed of an electronic signal in a copper wire, roughly 2/3rds the speed of light, maybe 200 million meters per second, otherwise a speed that would take a field of about 150 kilovolts to accelerate an electron to so this is clearly not happening.In fact, it is the electric field that is carrying the signal, not the electrons, for a 3 amp current in a mm^2 wire, the actual electrons "flow" from the negative to the positive terminal at less than a third of a millimeter per second.Assuming the hydraulic analogy physically translates to electron flow (and I can't blame people for this, books often don't bother correcting the misapprehension) is really only what makes us think there should be a connection between electron flow and current direction.

author: Brumby
author_rank: Unknown
timestamp: January 05, 2016, 05:21:54 am
content: Quote from: bobdabiulder on January 05, 2016, 01:59:13 amIt would be fairly safe to assume they are talking aboutconventionalcurrent flow - that is from positive to negative. That's how diode and transistor symbols have evolved and the general discussion of circuits follows this convention.Anybody who wishes to present their discussion based on the reverse (actual electron flow) would usually make it rather clear that this is what they are doing, since conventional current flow is the norm. Also, they are more than likely give their reasons for doing so.Then there are those who are just being plain pedantic - and while they may betechnicallycorrect, in most practical applications people will either roll their eyes (if they realise what's being said) or get confused (if they don't).In short - just stick with the idea that current flows from + to - because it works.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 05, 2016, 05:31:37 am
content: Quote from: jwm_ on January 05, 2016, 03:24:24 amelectrons do flow filling the space on the other side... the imbalance of charge (electrons) count is what makes the volt potential difference, in order to balance them in close system like a circuit, they do must flow until balance is reached (flat battery), exactly like water retention poll.

author: Gyro
author_rank: Super Contributor
timestamp: January 05, 2016, 11:28:38 am
content: Just a hint for your future postings, if you check out other thread titles they give some indication of what the question is about. A one word title of 'Confused' is likely to get passed by by a lot of people without bothering to open it (you've actually done pretty well on this one).

author: IanB
author_rank: Super Contributor
timestamp: January 05, 2016, 01:12:40 pm
content: As a blatant troll, this thread has done rather well. It caught lots of fish.

author: AF6LJ
author_rank: Unknown
timestamp: January 05, 2016, 01:22:26 pm
content: When you know how things work the direction electrons holes or whatever flow makes no difference. Make it easy on yourself the electrons flow in the direction of the arrow in a semiconductor diode. Tomas Edison was an idiot, and a not very smart one at that.

author: TimFox
author_rank: Super Contributor
timestamp: January 05, 2016, 02:49:29 pm
content: In a forward-biased semiconductor diode,conventional currentflows in the direction of the arrow--notthe "electron current".

author: AF6LJ
author_rank: Unknown
timestamp: January 05, 2016, 03:09:21 pm
content: I get the names mixed up, really don't give a damned what it is called the electrons always travel toward the positive, the holes go the opposite direction.The electrons boil off the cathode and get sucked up by the anode.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 05, 2016, 04:08:28 pm
content: Quote from: TimFox on January 05, 2016, 02:49:29 pmftfy

author: c4757p
author_rank: Super Contributor
timestamp: January 05, 2016, 04:20:27 pm
content: If the guy is confused, you're surely not doing anything to help, Mecha."electron current" is what it's usually called. Replacing it with your own favorite terminology certainly doesn't make it easier to understand.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 05, 2016, 06:50:46 pm
content: so its current current vs electron current then

author: AF6LJ
author_rank: Unknown
timestamp: January 05, 2016, 07:06:41 pm
content: Quote from: c4757p on January 05, 2016, 04:20:27 pmWhat you call it makes no difference whatsoever in what direction the electrons flow.I prefer to call it Squirtoutthejuice current.

author: IanB
author_rank: Super Contributor
timestamp: January 05, 2016, 07:32:16 pm
content: If we asked to prove that electrons exist, how would anyone go about that? For instance, in a vacuum tube I assert that when the cathode is heated it starts to attract and absorb positive particles that are emitted from the anode. How would you prove that is not the case?

author: rfeecs
author_rank: Frequent Contributor
timestamp: January 05, 2016, 07:51:08 pm
content: Quote from: IanB on January 05, 2016, 07:32:16 pmIt was proven long ago. Try googling discovery of electron.Cathode rays can cast a shadow, for example. That wouldn't happen if the particle was moving the opposite direction.

author: c4757p
author_rank: Super Contributor
timestamp: January 05, 2016, 08:11:43 pm
content: The point is that for normal circuit design and analysis, it doesn't matter.Quote from: AF6LJ on January 05, 2016, 07:06:41 pmNo, but calling it something different when trying to explain to a beginner just causes confusion.

author: AF6LJ
author_rank: Unknown
timestamp: January 05, 2016, 08:46:28 pm
content: Quote from: c4757p on January 05, 2016, 08:11:43 pmI have to admit I get conventional and electron flow confused.The point is it makes no difference. All the electrical laws work ether way.I apologize for adding to the confusion.

author: bobdabiulder
author_rank: Contributor
timestamp: January 05, 2016, 10:56:12 pm
content: Quote from: IanB on January 05, 2016, 01:12:40 pmI'm fourteen years old, I only started learning this stuff one year ago... I'm not a troll!

author: IanB
author_rank: Super Contributor
timestamp: January 06, 2016, 12:13:11 am
content: Quote from: bobdabiulder on January 05, 2016, 10:56:12 pmOK then.Quote from: bobdabiulder on January 05, 2016, 01:59:13 amBut this is where your problem lies. You are thinking that current flowing from + to - is not a fact, you are thinking that it is wrong.You must not think this way. It is absolutely the case that electric current flows from + to -. It is how physics and engineering defines electric current. It is how everyone designs electric circuits and does their calculations. It is how you will do things in school and in college when you study physics and engineering.If you follow the convention that everyone abides by, you will find it works just fine.

author: wraper
author_rank: Unknown
timestamp: January 06, 2016, 12:28:58 am
content: Electric current (carriers) not necessarily flows from minus to plus. Carriers can be positive and negative ions as well, not only negatively charged electrons. In such a case (electrolyte) positive ions move in the opposite direction to what you would expect from electrons. In plasma, current is carried by electrons and ions at the same time. So just stick with conventional current because "electron current" in not applicable in every situation at all.

author: Nerull
author_rank: Frequent Contributor
timestamp: January 06, 2016, 12:48:06 am
content: Quote from: wraper on January 06, 2016, 12:28:58 amThis is often forgotten in these discussions. Electrons are not the only charge carrier, and different charge carriers can move in different directions, so if you try to use the direction your charge carrier is moving as the direction of current flow, it will change depending on what your conductor is. Conventional current is independent of charge carrier, and so is always consistent.

author: hamster_nz
author_rank: Super Contributor
timestamp: January 06, 2016, 12:58:13 am
content: It might be just me, but I find the whole idea of holes flowing to be fundamentally silly (no matter how useful it is as a conceptual model). It is akin to the empty bit of road flows in a traffic jam, in the opposite direction to the traffic flow. Although you can point and go "the hole is here", "and now it is here", "and now it is here" it isn't the same hole.But then again, electrons in a current don't actually travel that fast either...with a 3 A current in a 1 mm copper wire, the electrons move at ?0.00028 m/s, taking an hour for the average electron to move 1 meter.

author: Brumby
author_rank: Unknown
timestamp: January 06, 2016, 01:20:39 am
content: As you can see, discussion on the subject brings out a variety of opinions and different points of view. Sometimes you will encounter things that are obscure, misleading but often the discussion simply gets more confusing, especially for someone just getting into electronics.A repost I know, but stick with this until you're ready to get into the detailed physics (which includes actual electron flow). Even when youareready, don't bother unless youknowyou have to. It's not needed for the vast majority of electronics.Quote from: Brumby on January 05, 2016, 05:21:54 am

author: Nerull
author_rank: Frequent Contributor
timestamp: January 06, 2016, 02:51:19 am
content: Who said anything about holes?In electrolytic solutions, such as salt water, the charge carriers are entire atoms, and they don't move from negative to positive. In proton conductors, seen in some fuel cells (and ice), H+ atoms carry the charges, and they don't even have electrons.And frankly, deciding something can't work because it doesn't make sense in a poor analogy is kind of silly. Anolgoies are useful tools for understanding, but its important not to confuse the analogy for the real process. Electrons are not cars driving down a road.Just stick to conventional current. Every data sheet, and every circuit, you will ever see will be in conventional current.If you're working on a device, like semiconductors, where you need to worry about the behavior of electrons in the circuit, you should already know enough about the fundamental processes that it isn't confusing anymore. If you're not working on those devices, it will never matter to you.

author: hamster_nz
author_rank: Super Contributor
timestamp: January 06, 2016, 03:20:28 am
content: Quote from: Nerull on January 06, 2016, 02:51:19 amAF6LJ did, back on the first page....Quote from: Nerull on January 06, 2016, 02:51:19 amI never said it didn't work - just that it seems a little silly to me. Hey, but that is quasiparticles for you...