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Topic: Which direction does current flow? (Read 4887 times) previous topic - next topic

Grumpy_Mike

A hole has a mass you can weigh it.
A hole can move in a substrate. It has velocity.
A hole can collide with other holes and bounce off them.

All these "missing" electron stories are just that, a convenience fiction for those who don't want to go too deep into the theory. Holes are real.

tinman13kup

I see a bunch of people who really got deep into this subject. I never learned too much about it, but I do know this-
  out of holes, electrons, and current-current is the one that will really get your attention
Tom
It's not a hobby if you're not having fun doing it. Step back and breathe

Southpark

#47
Jun 08, 2018, 11:47 pm Last Edit: Jun 09, 2018, 12:20 am by Southpark
I see a bunch of people who really got deep into this subject. I never learned too much about it, but I do know this-
  out of holes, electrons, and current-current is the one that will really get your attention
I think the main thing is just to consider (as these scientists appear to be suggesting) .... is to think of the universe as some kind of system .... some matrix, and for some unknown reason (simply unknown), there are building blocks.... or more like building 'forces'. So some combinations of these building 'forces' get together (somehow) to form things like fields, protons, quarks, sparks, neutrinos, electrons, photons, atoms, etc. The atoms and molecules appear to be what we 'define' as solid. All these physical 'stuff' is defined by humans --- we 'sense' them, or 'measure' them, or predict them ....and we define them.

In this universe, people don't even know what the origins are..... of electrons, holes, fields, etc. They just know how to define and measure these 'quantities'/'entities' that they see or sense, and know how to make use of them ----- ie. do things with them if they can.

So, as long as something like 'holes' is defined, then just treat holes as yet another physics defined 'thing'. And just use current as whatever it is defined to be by physicists....and use current as it is shown in circuit theory (ie. adopt a convention, and go for it).

As for OP's question of which direction does current flow..... if just focusing on basic circuit theory, just go with most circuit theory text books and use 'conventional' current flow ----- and use a sign convention for voltage, current and power .... aka 'passive sign convention'. You would only get into the hole and electron discussion when entering the physics area.

tinman13kup

Oh, I know our hobby end of electronics doesn't even scratch the surface of the big picture when it comes to physics. I just have a suspicion the Grumpy_Mike used to be known as Happy_Mike before college.
Tom
It's not a hobby if you're not having fun doing it. Step back and breathe

terryking228

#49
Jun 09, 2018, 01:01 am Last Edit: Jun 09, 2018, 01:53 am by terryking228
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when it comes to physics. I just have a suspicion the Grumpy_Mike used to be known as Happy_Mike before college.
I was only temporarily a  Uconn Physics Major (1958) , but I was only Grumpy because they wouldn't Frickin' let me TOUCH anything. "When you are a Senior, you can do a Project"..  Grr....  So I dropped out...

NOW: Every entering Engineering and Computer Science student goes to the Bookstore and BUYS MY KIT!  Barnes and Noble just ordered 700 for the Uconn bookstore.   OMG, it took 60 years to get my Revenge!  

I am so happy that times have changed and it's understood that early hands-on experience is vital to getting kids really involved with things that are INVISIBLE.  Like my kit says, "UH-OH! Electricity is INVISIBLE"..  

Mike, please explain (Yeah, I know... I didn't major in Physics..) how a "Hole" has measureable weight.  Is it the mass of a (for example Silicon) atom, minus the mass of an electron??  Hmmm....
Regards, Terry King terry@yourduino.com  - Check great prices, devices and Arduino-related boards at http://YourDuino.com
HOW-TO: http://ArduinoInfo.Info

ReverseEMF

A hole has a mass you can weigh it.
A hole can move in a substrate. It has velocity.
A hole can collide with other holes and bounce off them.

All these "missing" electron stories are just that, a convenience fiction for those who don't want to go too deep into the theory. Holes are real.
Science is just another mythology. Probably a better informed mythology than most, but when you get down to brass tacks, no one really knows what it all really is.  Any "scientist" who thinks otherwise, is living, and thinking in a deluded state. 
"It's a big galaxy, Mr. Scott"

Please DON'T Private Message to me, what should be part of the Public Conversation -- especially if it's to correct a mistake, or contradict a statement!  Let it ALL hang out!!

Johan_Ha

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no one really knows what it all really is.
A statement like this always makes me want to ask what it would mean or what it would take to really know what it all really is. To make a statement like that requires that you know. So by all means, tell us.
____________________

If you ask for help and write 'u' instead of 'you' because you think it's convenient, I will write 'no' instead of 'yes'. For same reasons.

Southpark

#52
Jun 09, 2018, 10:30 pm Last Edit: Jun 10, 2018, 03:19 am by Southpark
Science is about gathering information ... observations... via our senses and measurements and technology etc.... and recording/documenting those observations.... and then attempting to develop tools... mathematics and formulae and systems (definitions) etc. that not only allow observations to be explained in terms what is so-far known or built on.... but also to be able to utilise the knowledge gained from the relationships found or developed in the science.... applied science/engineering etc.... for technological advancement.

In science, we know that there are many things that we don't understand or know about the universe's behaviour or properties or origins etc. It's an effort toward understanding more, expanding our knowledge about the universe -- based on 'scientific' methods... and the definition of scientific is quite well defined....dictionary.

But .... this should really be discussed in the all-subjects area.

The OP is asking about which direction 'electrons' flow. Maybe the best answer is.... ignore electrons unless it becomes a physics discussion.... or if it becomes a semi-conductor physics/electronics discussion... which probably doesn't fall under the 'general electronics' category. Although, I can understand that 'electronics' itself contains the word 'electron'.

Grumpy_Mike

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OMG, it took 60 years to get my Revenge
Yes but it was sweet wasn't it.  :)

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Science is just another mythology. Probably a better informed mythology than most, but when you get down to brass tacks, no one really knows what it all really is.
I can see why you say that, but I would not say just another, I would say it is "the" mythology because it is consistent and can be proven through mathematics. If the maths doesn't work then it is rejected or at least worked arround. Now what that maths mean in Physical terms is open to interpretation and we are hampered basically by lack of imagination when trying to describe phenomenon that has no analogue in the world we perceive.

Take an electron's relationship with a nucleus, we know a few basic facts, like there is a lot of space between them and electrons carry discrete energy levels but the "model " of an orbit and shells is convenient but wrong. And so are all the other things we can draw an analogue to in the world we piecieve.

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how a "Hole" has measureable weight.
It just drops out of the maths when you describe what it is doing and how it works. I don't think any one has actually measured it but interestingly enough it does mean that an electron has a negitave mass, which just means the way it will react to a gravational field. And as we don't know what gravity actually is then that is all we can say about it.

Having been in both fields I can say that physicists don't think of electron flow as such unless they specifically need it, they all use conventional current. And for electronics engineered it doesn't matter one jot what way the current flows either convention will work as long as you are consistent. I think that is the basic misunderstanding of a beginner they think it matters because in a circuit the electricity will be used up by the first component it enters. Which is of course a noncense.

GolamMostafa

A hole has a mass you can weigh it.
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It is found that, when quantum mechanics is used to specify the motion within the crystal of n electron or hole on which an external field is applied, it is possible to treat the hole and electron as imaginary classical particles with effective masses mp and mn respectively. The approximation is valid that the externally applied fields are much weaker than the internal periodic fields produced by the lattice structure. In a perfect crystal these imaginary particles respond only to the external fields.

In conclusion, then, the effective-mas approximation removes the quantum features of the problem and allows us to use newton's laws to determine the effect of external forces on the elctrons and holes within the crystal.
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In general, however, the value of effective mass depends on the purpose for which it is used, and can vary depending on a number of factors. For electrons or electron holes in a solid, the effective mass is usually stated in units of the rest mass of an electron, me(mp) (9.11×10−31 kg).

ReverseEMF

A statement like this always makes me want to ask what it would mean or what it would take to really know what it all really is. To make a statement like that requires that you know. So by all means, tell us.
A while back, Bob Williams pointed the Hubble Space Telescope at a part of the sky that appeared empty.  Turns out, it wasn't so empty.  But, before that happened, I could have said, "Nobody knows what is beyond the farthest observable galaxy."  And, I wouldn't have know, myself.
So, I'm not sure what you're talking about.
"It's a big galaxy, Mr. Scott"

Please DON'T Private Message to me, what should be part of the Public Conversation -- especially if it's to correct a mistake, or contradict a statement!  Let it ALL hang out!!

ChrisTenone

Science is just another mythology. ...
No, science is NOT a mythology! Science is a methodology, not a set of beliefs.

A mythology is a dogmatic explanation for observations. Science is a series of actions about asking and developing answers to questions. Mythologies have the explanation already pre-set.

Scientists spend their time disproving beliefs, not the other way around.
What, I need to say something else too?

Grumpy_Mike

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Scientists spend their time disproving beliefs,
Quite right.

Well trying to at least. When they can't the conclude that they must be right. Then it is on to experimentation to see if they can spot what is predicted, like the recent discovery of gravational waves. They were predicted from the maths about 100 years ago.

Johan_Ha

When we have a spark jumping over a gap, it jumps from the negative electrode to the positive electrode, right? And the direction is even visible, right? That is one thing, where the actual physical direction of "matter" in an electrical current might have a meaning.

A spark plug lits up 40 times per second at 5000 rpm. Could it be that there's an advantage when the spark starts at the ground electrode instead of the firing pin? The ground electrode is nearer the centre of the combustion chamber.
____________________

If you ask for help and write 'u' instead of 'you' because you think it's convenient, I will write 'no' instead of 'yes'. For same reasons.

ReverseEMF

No, science is NOT a mythology!
It is, when scientists talk like current "knowledge" is fact.  Facts that often become yesterday's can-you-believe-we-used-to-think-that?  But, then, I would argue that they are not the best scientists.  

And doesn't Quantum mechanics give us president to wonder if things don't go all wonky when no one is looking?  We receive clues about the nature of reality from our senses, and some very smart people have made it possible to "see" beyond the range of our senses.  But, what if there are things out there that don't even come close to anything we perceive?  How would we even begin to ponder that?  It's entirely possible that what we take for "reality" is just something that was made up for us, to keep us entertained.  And all Math and Science do is piece together the delusion.
Is it not suspect, that we are measuring the Universe with the same stuff the Universe is made of?  A bunch of atoms trying to work out what atoms are.  Kind of like a ruler trying to measure itself, or a glass of water trying to drink [or grok] itself.
"It's a big galaxy, Mr. Scott"

Please DON'T Private Message to me, what should be part of the Public Conversation -- especially if it's to correct a mistake, or contradict a statement!  Let it ALL hang out!!

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