Reference direction of electrical current in teaching/books

[Rich Grise]

On Mon, 22 Jun 2009 18:19:51 -0700, stan wrote:

On Jun 22, 8:04 am, "Electronworks.co.uk"
newsgro...@electronworks.co.uk> wrote:
"Greegor" <Greego...@gmail.com> wrote in message

EW > (it looks like Phil agrees with me, which gives me a warm feeling
too (!))

Like wetting your pants?

!!!!

Now that made me laugh!

It's easy. Electrons are negative and are attracted to the positive.
Understand that (as in electron tubes or semi conductors) and put it
aside.
Now; as a convention it was decided long ago that current flow within
an electric circuit shall be shown as flowing from postive to
negative.
For example:
Positive terminals on things such as batteries are often marked or
shown in red. Negative terminals in various other colours, often
black, green. blue etc. When working on a circuit one assumes electric
current flows away from the positive part of any circuit towards
something less positive or in other words negative to the starting
point.

I've never been able to figure out how the phosphor of a CRT decides
which pixel to energize and emit a positron, when it doesn't even
know what the deflection coils are doing yet? >:->

Cheers!
Rich

 

[Rich Grise]

On Sat, 20 Jun 2009 20:18:24 -0700, George Herold wrote:

On Jun 20, 12:38 pm, John Larkin

This is insane gibberish.

Yup, that's a pretty crappy article. You can't believe everything you
read on wiki.

So, fix it!

Cheers!
Rich

 

[John Larkin]

On Tue, 23 Jun 2009 22:18:24 GMT, Rich Grise <richgrise@example.net>
wrote:

On Sat, 20 Jun 2009 09:35:50 -0700, John Larkin wrote:
On Sat, 20 Jun 2009 04:15:37 -0700 (PDT), eliben <eliben@gmail.com

Recently I ran into a book that teaches that current flows from the
negative to the positive terminal (i.e. across a resistor). This
implies electron flow and is opposed to all examples I've seen in
other books.

Perhaps someone knows of a resource that discusses this issue? I.e.
which way is more correct to teach, how have the current symbolics
developed, etc?

Thanks

The military and some tech schools (Heald, I think) start with
electron flow, and later switch to conventional current.

Not in the USAF, they didn't. We used electron flow from the
start, and stuck with it. It's really the only way to understand
how maagnetrons and klystrons and traveling wave tubes and backward
wave oscillators and such actually work. >:-

I never learned that electrons are positive, and I didn't have any
trouble understanding how tubes work.

So, do you flip the sign on all the test equipment you use, or does
the Air Force buy special backwards-reading meters and scopes?

John

 

[John Larkin]

On Tue, 23 Jun 2009 22:14:24 GMT, Rich Grise <richgrise@example.net>
wrote:

On Sat, 20 Jun 2009 04:15:37 -0700, eliben wrote:

Recently I ran into a book that teaches that current flows from the
negative to the positive terminal (i.e. across a resistor). This
implies electron flow and is opposed to all examples I've seen in
other books.

Perhaps someone knows of a resource that discusses this issue? I.e.
which way is more correct to teach, how have the current symbolics
developed, etc?


College boys use positive charge flow - techies use electron flow.

Which is why the college boys make more money, and tell the techies
what to do.

John

 

[Rich Grise]

On Wed, 24 Jun 2009 20:57:29 -0700, John Larkin wrote:

So, do you flip the sign on all the test equipment you use, or does
the Air Force buy special backwards-reading meters and scopes?

Now you're just being snotty.

Thanks,
Rich

 

[John Larkin]

On Thu, 25 Jun 2009 20:38:30 GMT, Rich Grise <richgrise@example.net>
wrote:

On Wed, 24 Jun 2009 20:57:29 -0700, John Larkin wrote:

So, do you flip the sign on all the test equipment you use, or does
the Air Force buy special backwards-reading meters and scopes?

Now you're just being snotty.

No, seriously, if you believe that positive current is the direction
that electrons move, how do you interpret the current reading of a
Fluke DVM? Do you mentally flip the sign it displays?

And do military schematics draw diodes the opposite way that everybody
else does?

What about the Right Hand Rule?

John

 

[Rich Grise]

On Fri, 26 Jun 2009 08:19:51 -0700, John Larkin wrote:

On Thu, 25 Jun 2009 20:38:30 GMT, Rich Grise <richgrise@example.net
On Wed, 24 Jun 2009 20:57:29 -0700, John Larkin wrote:

So, do you flip the sign on all the test equipment you use, or does
the Air Force buy special backwards-reading meters and scopes?

Now you're just being snotty.

No, seriously, if you believe that positive current is the direction
that electrons move, how do you interpret the current reading of a
Fluke DVM? Do you mentally flip the sign it displays?

Heavens, no! I'm astute enough to recognize that even though it's
electrons that flow from negative to positive it's not a dramatic
intuitive leap to realize that the results are functionally
indistinguishable.

What about the Right Hand Rule?

Sure! Works fine, for positive charge flow, or hole flow. Admittedly, for
electron flow it's the Left-Hand Rule, but the effects are
indistinguishable.

The difference, I guess, is that the college boys are insulated
from reality by the ivied halls of academia, and us techs do the
actual work. >:->

Thanks,
Rich

 

[stan]

John Larkin wrote:

On Thu, 25 Jun 2009 20:38:30 GMT, Rich Grise <richgrise@example.net
wrote:

On Wed, 24 Jun 2009 20:57:29 -0700, John Larkin wrote:

So, do you flip the sign on all the test equipment you use, or does
the Air Force buy special backwards-reading meters and scopes?

Now you're just being snotty.

No, seriously, if you believe that positive current is the direction
that electrons move, how do you interpret the current reading of a
Fluke DVM? Do you mentally flip the sign it displays?

And do military schematics draw diodes the opposite way that everybody
else does?

What about the Right Hand Rule?

Actually it's not necessary to flip anything and I think you know that
John. They simply teach that electrons enter the negative terminal of a
passive element. For diodes, electrons enter the "negative" side of a
diode and so on... Current meters are interprted as the quantity of
electrons flowing into the negative terminal of the meter.

The positive charge view is an arbitrary convention that dates from the
time of Ben Franklin. Negative charge flow is equally valid in every way
although it is certainly less intuitive if you try to understand things
from an energy point of view.

Every engineering text I have clearly refers to the fact that positive
charge flow is a convention. Some of the texts are quite old. Are you
saying none of your books explain "conventional" current flow?
>

 

[John Larkin]

On Mon, 29 Jun 2009 16:25:12 -0400, stan <smoore@exis.net> wrote:

John Larkin wrote:


On Thu, 25 Jun 2009 20:38:30 GMT, Rich Grise <richgrise@example.net
wrote:

On Wed, 24 Jun 2009 20:57:29 -0700, John Larkin wrote:

So, do you flip the sign on all the test equipment you use, or does
the Air Force buy special backwards-reading meters and scopes?

Now you're just being snotty.

No, seriously, if you believe that positive current is the direction
that electrons move, how do you interpret the current reading of a
Fluke DVM? Do you mentally flip the sign it displays?

And do military schematics draw diodes the opposite way that everybody
else does?

What about the Right Hand Rule?

Actually it's not necessary to flip anything and I think you know that
John. They simply teach that electrons enter the negative terminal of a
passive element. For diodes, electrons enter the "negative" side of a
diode and so on... Current meters are interprted as the quantity of
electrons flowing into the negative terminal of the meter.

The positive charge view is an arbitrary convention that dates from the
time of Ben Franklin. Negative charge flow is equally valid in every way
although it is certainly less intuitive if you try to understand things
from an energy point of view.

Every engineering text I have clearly refers to the fact that positive
charge flow is a convention. Some of the texts are quite old. Are you
saying none of your books explain "conventional" current flow?

All the physics and ee books that I have say that an electron has a
negative charge, and that current flows from positive to negative.

I've worked with a few military and Heald graduates who kept getting
confused about current directions and diodes and transistors, so
whatever they taught them wasn't helpful in the real world.

John

 

[Rich Grise]

On Mon, 29 Jun 2009 19:59:53 -0700, John Larkin wrote:

I've worked with a few military and Heald graduates who kept getting
confused about current directions and diodes and transistors, so
whatever they taught them wasn't helpful in the real world.

I can't imagine that it can be hard for some people to remember that

conventional current flows from positive to negative, while the electrons
flow from negative to positive to balance it out. ;-)

I guess my point is, IT DOESN't MAKE ANY DIFFERENCE! As long as you're
consistent.

One thing that does confuse me - which end of a battery is tha anode?
The end the positive charge comes out of?

Cheers!
Rich

 

[Nobody]

On Tue, 30 Jun 2009 18:53:20 +0000, Rich Grise wrote:

One thing that does confuse me - which end of a battery is tha anode?
The end the positive charge comes out of?

Positive charges don't come out of a battery

Electrons leave via the anode (marked with a "-") and enter via the
cathode (marked with a "+").

 

[Jasen Betts]

On 2009-06-30, Rich Grise <richgrise@example.net> wrote:

One thing that does confuse me - which end of a battery is tha anode?
The end the positive charge comes out of?

No, the end it flows into (thus it's the opposite terminal whilst recharging)

 

[John Larkin]

On Wed, 01 Jul 2009 11:06:30 +0100, Nobody <nobody@nowhere.com> wrote:

On Tue, 30 Jun 2009 18:53:20 +0000, Rich Grise wrote:

One thing that does confuse me - which end of a battery is tha anode?
The end the positive charge comes out of?

Positive charges don't come out of a battery

Not unless you connect the terminals with a liquid or a semiconductor
or a photoconductor or an ionized gas.

Electrons leave via the anode (marked with a "-") and enter via the
cathode (marked with a "+").

A quick google search is about equally divided on the polarity of the
anode.

I like the voltage convention, where "anode" is always the more
positive terminal. But it doesn't much matter.

John

 

[John Fields]

On Wed, 01 Jul 2009 09:31:14 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Wed, 01 Jul 2009 11:06:30 +0100, Nobody <nobody@nowhere.com> wrote:

On Tue, 30 Jun 2009 18:53:20 +0000, Rich Grise wrote:

One thing that does confuse me - which end of a battery is tha anode?
The end the positive charge comes out of?

Positive charges don't come out of a battery

Not unless you connect the terminals with a liquid or a semiconductor
or a photoconductor or an ionized gas.

---
Those aren't positive charges, they're just places where electrons
ain't. The putatative "holes".
---

Electrons leave via the anode (marked with a "-") and enter via the
cathode (marked with a "+").

A quick google search is about equally divided on the polarity of the
anode.

---
Which means what?
---

I like the voltage convention, where "anode" is always the more
positive terminal. But it doesn't much matter.

---
Bottom line is it really does, but from your perspective you can't see
that.

JF

 

[John Larkin]

On Fri, 03 Jul 2009 17:51:00 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Wed, 01 Jul 2009 09:31:14 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Wed, 01 Jul 2009 11:06:30 +0100, Nobody <nobody@nowhere.com> wrote:

On Tue, 30 Jun 2009 18:53:20 +0000, Rich Grise wrote:

One thing that does confuse me - which end of a battery is tha anode?
The end the positive charge comes out of?

Positive charges don't come out of a battery

Not unless you connect the terminals with a liquid or a semiconductor
or a photoconductor or an ionized gas.

---
Those aren't positive charges, they're just places where electrons
ain't. The putatative "holes".

A nucleus isn't a hole. It is full of real positive charges, known as
"protons."

Photoconductors do have holes; the protons don't move much. In ioninic
liquids and ionized gasses, the positive charges - protons - do in
fact move from the positive terminalo to the negative.

---

Electrons leave via the anode (marked with a "-") and enter via the
cathode (marked with a "+").

A quick google search is about equally divided on the polarity of the
anode.

---
Which means what?
---

I like the voltage convention, where "anode" is always the more
positive terminal. But it doesn't much matter.

---
Bottom line is it really does, but from your perspective you can't see
that.

It's sort of useless to have terms that change meaning many times a
second. Using the "current" standard, when a battery is delivering
current, its pos terminal is the cathode, but when it's being charged
it's the anode. That can change 120 times a second. Even more fun is a
PV diode, where the diode anode is the cathode when it's generating
power.

Which is why actual electrical engineers seldom use the words "anode"
and "cathode" unless they are referring to a diode or a vacuum tube,
and I've never heard an engineer switch the names of the diode ends
when it operated in zener or PV mode.

I always call the p-doped side of a diode "anode."

Do you call the banded end of a diode "anode" when it's zenering but
"cathode" when it's forward conducting?

John

 

[Greg Ewing]

John Fields wrote:

Those aren't positive charges, they're just places where electrons
ain't. The putatative "holes".

Although in semiconductors, apparently, due to some quantum
reason that I don't fully understand, the holes really do
behave as though they were positively charged particles.

The difference shows up in the Hall effect, where positive
charges moving one way are *not* equivalent to negative
charges moving the other way. The Hall voltage generated
by a p-type semiconductor is what you expect from moving
positive charges.

If anyone can provide an intuitive explanation of that,
I'd be most interested...

--
Greg

 

[John Fields]

On Fri, 03 Jul 2009 20:59:18 -0700, John Larkin
<jjSNIPlarkin@highTHISlandtechnology.com> wrote:

On Fri, 03 Jul 2009 17:51:00 -0500, John Fields
jfields@austininstruments.com> wrote:

On Wed, 01 Jul 2009 09:31:14 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Wed, 01 Jul 2009 11:06:30 +0100, Nobody <nobody@nowhere.com> wrote:

On Tue, 30 Jun 2009 18:53:20 +0000, Rich Grise wrote:

One thing that does confuse me - which end of a battery is tha anode?
The end the positive charge comes out of?

Positive charges don't come out of a battery

Not unless you connect the terminals with a liquid or a semiconductor
or a photoconductor or an ionized gas.

---
Those aren't positive charges, they're just places where electrons
ain't. The putatative "holes".

A nucleus isn't a hole.

---
Who said it was?
---

It is full of real positive charges, known as "protons."

---
Nope, it's full of protons _and_ neutrons, you patronizing ass.
---

Photoconductors do have holes; the protons don't move much.

---
The protons don't move at all unless the whole atom does.

The electrons do, though, and when an electron jumps from a neutral atom
to one which it finds more attractive, the space it leaves in its
previous orbital creates a hole and makes the atom it left an
electrically positive ion.
---

In ioninic liquids and ionized gasses, the positive charges - protons - do in
fact move from the positive terminalo to the negative.

---
"Ioninic"???

"Terminalo"???

Surely you had too much alcohol in your system when you decided to post
some more of your nonsense and didn't reealize that protons bound to the
nucleus don't have the mobility you claim they do, or you're just
stupid.

Which is it?

---

JF

 

[John Larkin]

On Sat, 04 Jul 2009 18:00:04 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Fri, 03 Jul 2009 20:59:18 -0700, John Larkin
jjSNIPlarkin@highTHISlandtechnology.com> wrote:

On Fri, 03 Jul 2009 17:51:00 -0500, John Fields
jfields@austininstruments.com> wrote:

On Wed, 01 Jul 2009 09:31:14 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Wed, 01 Jul 2009 11:06:30 +0100, Nobody <nobody@nowhere.com> wrote:

On Tue, 30 Jun 2009 18:53:20 +0000, Rich Grise wrote:

One thing that does confuse me - which end of a battery is tha anode?
The end the positive charge comes out of?

Positive charges don't come out of a battery

Not unless you connect the terminals with a liquid or a semiconductor
or a photoconductor or an ionized gas.

---
Those aren't positive charges, they're just places where electrons
ain't. The putatative "holes".

A nucleus isn't a hole.

---
Who said it was?
---

It is full of real positive charges, known as "protons."

---
Nope, it's full of protons _and_ neutrons, you patronizing ass.

Hydrogen? Hydrogen is a major charge carrier in lots of situations.
Situations that keep you alive.

---

Photoconductors do have holes; the protons don't move much.

---
The protons don't move at all unless the whole atom does.

Not precisely true, since you're in one of your bitchy moods.

The "whole atom" includes all the electrons, and a positive ion is
missing some. A hydrogen ion *is* a naked proton.

The electrons do, though, and when an electron jumps from a neutral atom
to one which it finds more attractive, the space it leaves in its
previous orbital creates a hole and makes the atom it left an
electrically positive ion.
---

In ioninic liquids and ionized gasses, the positive charges - protons - do in
fact move from the positive terminalo to the negative.

---
"Ioninic"???

"Terminalo"???

Surely you had too much alcohol in your system when you decided to post
some more of your nonsense and didn't reealize that protons bound to the
nucleus don't have the mobility you claim they do, or you're just
stupid.

I never claimed to be a typist. And just how much mobility do you
think I documented, that you think they have less of?

Maybe you need a drink. You're sure in a bad mood.

John

 

[greg]

John Larkin wrote:

The "whole atom" includes all the electrons, and a positive ion is
missing some. A hydrogen ion *is* a naked proton.

And apparently the conductivity of ice is due to the
motion of protons rather than electrons:

http://skua.gps.caltech.edu/hermann/ice.htm

From that page:

"Proton conduction in ice and H-bonded materials is analogous to electron
conduction in semiconductors."

I wonder if you could make a transistor out of ice...

--
Greg

 

[John Fields]

On Sat, 04 Jul 2009 17:16:16 -0700, John Larkin
<jjSNIPlarkin@highTHISlandtechnology.com> wrote:

On Sat, 04 Jul 2009 18:00:04 -0500, John Fields
jfields@austininstruments.com> wrote:

On Fri, 03 Jul 2009 20:59:18 -0700, John Larkin
jjSNIPlarkin@highTHISlandtechnology.com> wrote:

On Fri, 03 Jul 2009 17:51:00 -0500, John Fields
jfields@austininstruments.com> wrote:

On Wed, 01 Jul 2009 09:31:14 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Wed, 01 Jul 2009 11:06:30 +0100, Nobody <nobody@nowhere.com> wrote:

On Tue, 30 Jun 2009 18:53:20 +0000, Rich Grise wrote:

One thing that does confuse me - which end of a battery is tha anode?
The end the positive charge comes out of?

Positive charges don't come out of a battery

Not unless you connect the terminals with a liquid or a semiconductor
or a photoconductor or an ionized gas.

---
Those aren't positive charges, they're just places where electrons
ain't. The putatative "holes".

A nucleus isn't a hole.

---
Who said it was?
---

It is full of real positive charges, known as "protons."

---
Nope, it's full of protons _and_ neutrons, you patronizing ass.

Hydrogen? Hydrogen is a major charge carrier in lots of situations.
Situations that keep you alive.

---
Doing the "Larkin shuffle" again, huh?

Above, you stated:

"It is full of real positive charges, known as "protons.""

Note that you used the plural, "charges", which shows that you weren't
thinking about elemental hydrogen, "1H", the nucleus of which comprises
a single proton, yet that's what you try to change the subject with.
---

Photoconductors do have holes; the protons don't move much.

---
The protons don't move at all unless the whole atom does.

Not precisely true, since you're in one of your bitchy moods.

---
How typically Larkinese; just more sidestepping bullshit, since my state
of being has nothing to do with the mobility of protons.
---

The "whole atom" includes all the electrons, and a positive ion is
missing some. A hydrogen ion *is* a naked proton.

---
Because the apparent conclusion is true, then what went before must also
be true?

Again, typical Larkinese "logic".
---

The electrons do, though, and when an electron jumps from a neutral atom
to one which it finds more attractive, the space it leaves in its
previous orbital creates a hole and makes the atom it left an
electrically positive ion.
---

In ioninic liquids and ionized gasses, the positive charges - protons - do in
fact move from the positive terminalo to the negative.

---
"Ioninic"???

"Terminalo"???

Surely you had too much alcohol in your system when you decided to post
some more of your nonsense and didn't reealize that protons bound to the
nucleus don't have the mobility you claim they do, or you're just
stupid.

I never claimed to be a typist.

---
It's not about being a typist, it's about not being sloppy.
---

And just how much mobility do you think I documented, that you think they have less of?

---
Think about it like this:

Consider the nucleus of an atom to be like an airplane full of people
and baggage, the people being protons and the baggage being neutrons.

In addition, escorting the airplane is a formation of fighter jets, the
electrons.

The way you paint the picture is that the people and their baggage are
free to leave the nucleus at any time, when what's really true is that
they're sealed in the airplane and the fighters are the only ones free
to break formation and leave the "atom" with a net positive charge.

JF