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Which way does current flow?

Which way does YOUR current flow?

  • Electron Flow - to +

    Votes: 0 0.0%
  • Conventional + to -

    Votes: 0 0.0%

  • Total voters
    0
  • Poll closed .
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kinarfi

Well-Known Member
From the "Inductive Kick and Snubber help" thread, conventional and electron current flow became a discussion, Myself, I've always used electron flow - to + as current flow while ericgibbs, giftiger_wunsch and crutschow prefer conventional current flow of + to -. I'm thinking it's all in how we learned electronic and was wondering if one is really more standard than the other.

Which do prefer for current flow?
Conventional
Electron
 

microtexan

New Member
Isn't that why it's called "Conventional Flow"?:p
 
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crutschow

Well-Known Member
Most Helpful Member
If the early experimenters had originally guessed correctly about the polarity of electrical charge carriers for electricity we wouldn't be having this discussion. But Murphy says if there's a 50% chance of being right, then it's quite likely you will be wrong.
 

Dean Huster

Well-Known Member
'Tis a shame that you didn't add a "both ways" option. Electron flow is wonderful for explaining a lot of general theory; conventional tends to work out a lot better on the engineering front.
 

unclejed613

Well-Known Member
Most Helpful Member
i voted "Electron flow - to +" because it is correct, but when explaining the operation of an amp with a bipolar (+/- rails with complementary devices) output stage, it helps to be "fluent" in electron flow AND conventional flow. it's not the most accurate approach, but it's easier than the convolutions you would have to go through explaining the positive half of the amp using electron flow...... what i have yet to figure out is WHY semiconductors use arrows pointing in the direction of conventional current flow, when these symbols were created 70 or more years after the discovery that electron flow goes from - to + (Crookes' cathode ray tube )
 

crutschow

Well-Known Member
Most Helpful Member
One of the reasons I voted current flow is that most circuits are negative ground and, to me, it's easier to follow current flow from positive to ground, then to follow electron flow from ground to positive.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Crappy poll - and pretty pointless :D

Why would you even want to know which way anything flows?, it makes no difference whatsoever.

Personally I either consider it flows from the top of the circuit down to the bottom, regardless of polarity - or flows from collector to emitter, regardless of PNP/NPN and which the transistor is connected.

But it's all in your head, and has no meaning.
 

MrAl

Well-Known Member
Most Helpful Member
Hi,


You really have to know both ways of doing it...to be able to think in both
conventions because depending on what you are reading the author may have
chosen one way or the other, and you will have to put up with that convention
if you intend to read their book or paper or whatever they have published.

In physics electron flow is quite often used, while in control theory positive
to negative is used more often because it simplifies the notation: no sign
to have to keep writing and keeping track of. Also, conventional positive
to negative flow is often used when there wont be a problem with not
maintaining the sign through the equations, which tend to appear with
natural phenomena rather than some pure theory.

As a quick illustration, using conventional current flow the current through a
resistor of fixed value energized with a voltage source of E volts is calculated from:
I=E/R

but if we were to use electron current flow we would have to write instead:
I= -E/R

The negative sign makes the equations a little messier, and also
which would you rather do repeatedly?
 
Last edited:

Nigel Goodwin

Super Moderator
Most Helpful Member
As a quick illustration, using conventional current flow the current through a
resistor of fixed value energized with a voltage source of E volts is calculated from:
I=E/R

but if we were to use electron current flow we would have to write instead:
I= -E/R

The negative sign makes the equations a little messier, and also
which would you rather do repeatedly?
Sorry, but a completely wrong and pointless 'example' - Ohm's law isn't affected in any way by current flow direction.
 

MikeMl

Well-Known Member
Most Helpful Member
Defining current flow as the movement of electons is fine, but if you think of it as a POSITIVE value, it forces you into the following unnatural conventions:

1. Current flows IN to the positive terminal of a voltage source.

2. Current flowing into a one end of a resistor creates a negative voltage at that end with respect to the other end.

If OTOH, you define the movement of electrons as a NEGATIVE current, then the (mathematically and natural) conventions apply:

1. Conventional Current flows OUT of the Positive terminal of a voltage source.

2. Conventional Current flowing into a one end of a resistor creates a Positive voltage at that end with respect to the other end.
 

unclejed613

Well-Known Member
Most Helpful Member
i once worked with a tech who repaired tube amps almost exclusively. he had a lot of difficulty with bipolar transistor amps, especially with the use of current sources in the input stages. i told him to think of them also as current sinks, and it made more sense to him.....
 

Bob Scott

New Member
If you are a student and learn that electrons flow from - to + and consider that to be current flow, then you have to unlearn that in order to "get with the flow" of the conventional thought on current flow. Otherwise you will get confused with all the arrows on transistor and diode symbols. In engineering it is handy to know conventional current flow.
 

PatM

Member
It is not important which method you use as long as you are consistent.
When I was in the Army Radio Repair school in 1954, we were instructed that flow was from - to +.
After working for AT&T and Rockwell Automation, and teaching ham radio classes I had no problems while using this convention.
Just stick with your method and you will have no problems.

PatM - W9ZO
Amateur Extra license
FCC 1st class licensee with ship radar endorsement
 

bountyhunter

Well-Known Member
From the "Inductive Kick and Snubber help" thread, conventional and electron current flow became a discussion, Myself, I've always used electron flow - to + as current flow while ericgibbs, giftiger_wunsch and crutschow prefer conventional current flow of + to -. I'm thinking it's all in how we learned electronic and was wondering if one is really more standard than the other.

Which do prefer for current flow?
Conventional
Electron
This is kind of a moot question because current flows like it flows, it isn't a matter of opinion. Electrons flow from minus to plus, and holes flow from plus to minus. It may be convenient to visualize current as flowing from the positive terminal to the negative terminal, as long as we all know what the truth is.
 
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MrAl

Well-Known Member
Most Helpful Member
Sorry, but a completely wrong and pointless 'example' - Ohm's law isn't affected in any way by current flow direction.
Then how do 'you' account for a negative current in response to
a positive supply with *any* load?
 

BrownOut

Banned
Outside of the military, most circuit analysis will be in convential flow ie + to -. Although it can be done either way, you should be comfortable with conventional, and electron flow too for that matter.
 
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