Which is currently being taught; electron flow or conventional flow?

[W9GFO]

When discussing something like how current travels through a transistor do professors and/or people in the industry describe the behavior in terms of electron flow or in conventional flow? I know that the difference between electron flow and conventional flow is taught, but if the flow type is not specified how do you know which is being used?

I came across some course material that described the operation of an NPN transistor in the same way that I would expect a PNP transistor to be described - I thought that it was an error, however it was intentional. Depending upon which flow the describing person is using, either could be correct. If the type of flow is not specified, which is the correct one to use?

[I wanted a rude username]

I expect to see conventional at the level of engineering. The boundary generally lies somewhere in the domain of physics. Conventional current is a useful and consistent abstraction; for instance, it cleanly bundles together all charge carriers, including protons, electron holes, etc.

Of course, the difference absolutely needs to be taught.

[IanB]

When discussing something like how current travels through a transistor do professors and/or people in the industry describe the behavior in terms of electron flow or in conventional flow? I know that the difference between electron flow and conventional flow is taught, but if the flow type is not specified how do you know which is being used?

It depends on the context. If studying engineering at professional level (bachelors, masters or above) then the question will not be important and will not be worthy of discussion. Quite simply voltage has increasing positive potential when measured from more positive to less positive, and current has a tendency to flow with a positive sign from points with a more positive potential to points with a less positive potential. All equations and calculations will be based on this standard convention.

The idea of electron flow or conventional flow may be taught in elementary classes in high school to give students a grounding in atomic theory, but once introduced it will soon be left behind.

Semiconductor physicists of course are in different world and know exactly what they are doing, but their work is in a specialized domain and is not relevant to general education.

[IanB]

I came across some course material that described the operation of an NPN transistor in the same way that I would expect a PNP transistor to be described - I thought that it was an error, however it was intentional. Depending upon which flow the describing person is using, either could be correct. If the type of flow is not specified, which is the correct one to use?

That image you posted seems incorrect. An NPN transistor will be biased towards the on state when a positive voltage appears at the base relative to the emitter and consequently a positive current will flow into the transistor at the base.

It is best to ignore such materials as that one that seem written to confuse people.

[T3sl4co1l]

Does the Navy still do electron flow?  Even if not, you'll likely find plenty of old material from when they did.

It doesn't actually matter, as long as it's consistent.

Tim

[KL27x]

If this is a vote, I'd say the descriptions in your upload/link are whack. Conventional current should be understood as the defacto, unless otherwise specified. And in this case it has not been otherwise specified.

Doesn't matter which way the electrons go. The current is positive to negative, by convention. They could specify by saying electron flow rather than current.

[magic]

Doesn't matter which way the electrons go. The current is positive to negative, by convention. They could specify by saying electron flow rather than current.

And they would still be wrong because half of the time it's the holes that make all the difference

Teaching this electron current convention and pretending that it's the norm is totally at this point.
Why is the arrow pointing outwards if you say it's a small current flowing from E to B, huh?

[ocw]

Electronics 101:  Electronic current flow is from positive to negative since this is what the first people working with electronics (do not say 'incorrectly") speculated.  In tubes, the filament attracts "positrons" being emitted from the plate.

Electronics 301:  We lied to you in Electronics 101 about electric current, forget everything which we taught you, here is what is actually true...

Continuing a lie because it was once thought true (the earth is flat) does not make sense.  Long ago, in my early teens, I could handle electron flow, holes (a missing electron moving, not protrons), etc. from the beginning of my electronic education.

[NiHaoMike]

Why are Native Americans still called "Indians"?

[German_EE]

For as long as I can remember I have been taught that in an NPN transistor current enters the base and collector and flows out of the emitter. This implies that current flow is positive to negative.

However, the cathode in a vacuum tube emits electrons which then flow through the grid)s) to the anode, meaning that in a vacuum tube circuit the flow is from negative to positive.

I shall therefore carry on working with transistors.

[james_s]

There's a reason it's called "conventional flow".

Every EE knows that electrons actually flow from negative to positive but in most cases conventional flow is used because it's the convention. When you are designing or analyzing a circuit it doesn't matter which way the electrons are flowing since you can't see them anyway. Pretend they are flowing from positive to negative because that's how all of the schematic symbols are defined. If you're working with vacuum tubes it may be helpful to think in terms of electron flow but how many people are doing that anymore? Those that are already know.

[SiliconWizard]

Every EE knows that electrons actually flow from negative to positive but in most cases conventional flow is used because it's the convention. When you are designing or analyzing a circuit it doesn't matter which way the electrons are flowing since you can't see them anyway.

Fully agree.
The rest is just wank.
(Of course the basics still need to be known, but as you said, that doesn't serve any purpose when analyzing a circuit.)

[T3sl4co1l]

Some day I want to do some glassblowing and make a proton tube.  I don't think much of a "space charge" can be made (we must start with neutral dihydrogen, so on the order of >13.6eV is required to do anything; the resulting "virtual anode" will be about as hot), which will greatly limit available current (and perveance), but other than that, the transconductance and transit time should be perceptibly, and proportionally, worsened (i.e., by ~2000x).  Transit time is typically a few ns for electron types, so at some µs, it will be obvious on the oscilloscope.

Tim

[bson]

There's a reason it's called "conventional flow".

Every EE knows that electrons actually flow from negative to positive but in most cases conventional flow is used because it's the convention.

Well, like pretty much every other EE I was taught somewhere around day 1 that I = Q/t.  Hence, positive current is a positive charge flow.  Because electrons are negatively charged they flow in a direction opposite to the current.  Signs matter.

[bob91343]

A 'hole' is a missing electron.  If a hole flows, it will be in the conventional, or positive direction.  However, a hole isn't something tangible - it's something missing.  In order for a hole to move, an electron has to fill the hole from somewhere else, and thus it's still electron flow.  After all, a vacuum cleaner doesn't suck, it simply moves air in such a way as to cause atmospheric pressure to move air in a desired direction.

Having said all that, as an engineer I have always used conventional current.  I had to change, as my college classes required it.  It's never caused a problem, and I automatically think in terms of conventional current.  That allows me to analyze and design with PNP or NPN for instance.

About the only time it feels right to work with electron flow is when analyzing the inner workings of a vacuum tube.  Which way does current flow in a voltage regulator tube or a neon bulb?

[MT]

1:Why was schematics drawn the conventional way and not the unconventional way whos the right way?
2:Why do American Indians get angry when labelled Native Americans? despite Vikings saw them before Christopher Columbus!?
3:Why is electrons described as ball to fill a hole when physics describe electrons to be everywhere and nowhere orbiting around the nucleus?

[NiHaoMike]

Why do American Indians get angry when labelled Native Americans? despite Vikings saw them before Christopher Columbus!?

Things are going to get interesting with the rise of (actual) Indians in the US. How would you describe their children? They're genetically Indians, but they're born in the US.

[I wanted a rude username]

Things are going to get interesting with the rise of (actual) Indians in the US. How would you describe their children? They're genetically Indians, but they're born in the US.

Wouldn't they just be "Americans"?

[T3sl4co1l]

If you ask them what they prefer to be called, they'll say "Indians".

Tim

[I wanted a rude username]

Interesting. But perhaps it is Australia that is the odd one out, since official documents here don't ask about race ... at most it's country of birth.

(The one exception to this policy is Aborigines and Torres Strait Islanders, who make up about 3% of the population. The census, university applications, etc. do specifically ask about these two ethnicities. Members of these groups seem much more likely to identify as such, though that doesn't mean there's any causal relationship, as the situation is roughly as complex as that of Native Americans in the US.)

[EEVblog]

This thread had better stay on topic...

[vk6zgo]

Doesn't matter which way the electrons go. The current is positive to negative, by convention. They could specify by saying electron flow rather than current.

And they would still be wrong because half of the time it's the holes that make all the difference

Teaching this electron current convention and pretending that it's the norm is totally at this point.
Why is the arrow pointing outwards if you say it's a small current flowing from E to B, huh?

"Holes" are a useful fiction describing the supposed flow of the place where an electron formerly was----in the opposite direction to the direction in which the displaced electron travels.

It is not usual to refer to "holes" when describing current flow in conductors.

The "arrow" points outwards because it follows the convention set up in the early days of electronics, which used "Conventional Current Flow".
The convention for drawing CCF is with the arrow point pointing away from the more positive side of the circuit, & towards the more negative side.

How does a vacuum tube work, using CCF, huh?

[sibeen]

Does the Navy still do electron flow?  Even if not, you'll likely find plenty of old material from when they did.

It doesn't actually matter, as long as it's consistent.

Tim

Below is the response I gave in a recent thread about sign. It's not just the US navy that goes down this route, I started in electronics in the Oz army. :

I had to think about this and grinned to myself when reading this as I suspect that I change which way I define the direction depending upon which day of the week it is. This may be a result of my electrical education. I started out with a four year apprenticeship as an electronics tech in the late 70s. The interesting tidbit is that military techs, at least in the English speaking portion of the world, get taught electron flow. I've never been able to track down the why of that and it's always interested me as to why that occurred. A few years later I decided to go down the university route and was taught the correct conventional current flow.

Still to this day when I'm looking at a circuit I'll revert to electron flow and this occasionally causes consternation with people I'm showing the workings to as "I'm doing it wrong" only to be a tad bemused when my answer turns out to be the correct one.

[SiliconWizard]

Still to this day when I'm looking at a circuit I'll revert to electron flow and this occasionally causes consternation with people I'm showing the workings to as "I'm doing it wrong" only to be a tad bemused when my answer turns out to be the correct one.[/i]

The whole point of "conventional" is to make things understandable and unambiguous to all. I'm not sure what kind of fun you'd find in not following the most usual convention just to feel "correct" (whereas, as some have explained above, correct here is just another convention anyway, but as the above sentence shows  - it was consterning people - a much less common convention in this particular context).

Probably gives some a feeling of superiority. Oh well. As long as the design and analysis is correct, who cares? Have you actually seen an electron yet?

Oh, but one common situation where conventions can still be mixed up is with some electronic symbols such as transistors. MOS transistors, for instance, are usually represented with the arrow in the opposite direction depending - usually - on whether the symbol is meant as a "raw" transistor (on microelectronics schematics for instance) or as a discrete one...

[German_EE]

In a similar vein there is something that I need help with

An NPN transistor is used in a negative ground circuit and the transistor symbol has the arrow pointing AWAY from the device

AN N-Channel MOSFET is used in a negative ground circuit and the MOSFET symbol has the arrow pointing TOWARDS the device.

Please could someone explain what is going on here?