Nobody cares about which hole or which electron is responsible for current. That is, the electron flowing from the battery does not complete the circuit, everyone can see that. Most people do not care about the WIP (Work in process) or all the electrons that are in the wire, we only need to know about how many move into the wire and out of the wire. Also, if you think about a material like a free atom in space, you are completely wrong about the Fermi bands of conduction. Materials behave much more differently than free atoms. Therefore, look up metallic bonding, conduction bands and various other concepts in solid state physics to explain the details of electron flow if that is what you want to know. Fortunately, Engineers learn how to lump concepts that describe a system well enough that it can be used as a basis for a design that solves a problem. They do not need to know exactly how an electron moves through a wire, they just need to know that electrons move into and out of wires at a reliable rate with pre-determined effects. if the existing model does not meet their needs (as in the high-voltage ion implant concept above), additional factors must be included like the counterflow of positive ions.

No need to make anything more complicated under the guise of being more correct than it needs to be.

 

Hello Brian (is it Brian?)

Look at any complete loop and mark two points A and B along the loop.

Call these the battery (or other source) terminals.

Now allow current to flow around the complete loop.

If the current flows from A to B the long way round which way will it flow the short way?

I'm guessing you are talking to me and it is Bill. I'm guessing from your loopy analogy, that you are trying to say that it can flow either way as long as it flows. I think Gopher T summed it up nicely and I have to agree with him. The OP asked a simple question,and now we have a quantum physics course going on. I thought he was looking for a simple answer, and I thought it should have been. I am not a physics major but I just find sometimes on this forum, there is a lot of one upmanship and its a challenge to see who is smarter than who. I think everybody has something to offer but if it's a simple question, a simple answer should suffice. Everybody has a theory and I'm sure, parts of all of them are true. Can they be proven, maybe, probably, but he just asked a simple question.

 

I am a new member to this forum. But I have never seen this response to a specific question. Nobody cares. It's the first question of electronics. EVERYBODY wants to know and understand this. This is fundamental and over 100 yrs. old. As you can see from the responses...we still don't know. I and many people want to know exactly and completely what current is and how it moves thru a wire.

 

You are just as likely to feel a shock if touching -100V as +100V. The cells in your finger do not care which way the electrons are swimming

I believe there is a difference, though, in the damage that is done to the "entrance" versus "exit" wounds. (I suppose "exit" is the lower potential spot.) Perhaps I am just recalling lightning damage, where there are geometric reasons for the lopsided damage.

Can you detect polarity of a high voltage DC source by "feel"? Seems unlikely now that I ask it that way. I think both poles of a 9V battery feel the same on the tongue.

 

Thanks all.

I was after an answer that made sense, weather that be simple or pointed me in the correct direction for further research. And I do care even though the answer is mostly irrelevant for everyday circuits, I was hoping understanding the/a basic theory better would help me visualise the circuit while learning. I also just could not get my head around why the more positive terminal was the one that was effectively dangerous even though its where the electrons flow to.

I get the impression no one actually knows for sure, and thanks to this thread I actually have a way to visualise the current flow.

I was expecting this type of discussion and its exactly why I signed up to this forum.

Thank You.

 

... I also just could not get my head around why the more positive terminal was the one that was effectively dangerous even though its where the electrons flow to....

Please post a link to where you learned this... My point is that I don't believe it...

 

Please post a link to where you learned this... My point is that I don't believe it...

If electricity is a flow of electrons, which have a negative charge, why do people talk as if electricity flows from the positive terminal to the negative terminal of a battery? The answer lies in a fundamental embarrassment in the history of research into electricity. For various reasons, when Benjamin Franklin was trying to understand the nature of electric current by studying phenomena such as lightning during thunderstorms, he believed he observed a flow of “electrical fluid” from positive to negative. He proposed this concept in 1747. In fact, Franklin had made an unfortunate error that remained uncorrected until after physicist J. J. Thomson announced his discovery of the electron in 1897, 150 years later. Electricity actually flows from an area of greater negative charge, to some other location that is “less negative”— that is, “more positive.” In other words, electricity is a flow of negatively charged particles. In a battery, they originate from the negative terminal and flow to the positive terminal.

Platt, Charles (2009-11-23). Make: Electronics: Learning Through Discovery (Kindle Locations 1076-1084). Maker Media, Inc. Kindle Edition.

This kind of information is all over the net as well, i.e. http://amasci.com/amateur/elecdir.html

I think I answered my own question in the first post, but I'm not sure. The positive terminal has a deficit of electrons (well compared to the other side of the circuit). If I touch say +400v I am completing the circuit which may or may not be via ground depending if I was dumb enough to be touching neutral as well.

Mike

Mike

 

I'm guessing you are talking to me and it is Bill. I'm guessing from your loopy analogy, that you are trying to say that it can flow either way as long as it flows. I think Gopher T summed it up nicely and I have to agree with him. The OP asked a simple question,and now we have a quantum physics course going on. I thought he was looking for a simple answer, and I thought it should have been. I am not a physics major but I just find sometimes on this forum, there is a lot of one upmanship and its a challenge to see who is smarter than who. I think everybody has something to offer but if it's a simple question, a simple answer should suffice. Everybody has a theory and I'm sure, parts of all of them are true. Can they be proven, maybe, probably, but he just asked a simple question.

I'm sorry I guessed your name wrong, I hope no offence was taken.

I didn't say the above, and it's obvious you didn't try the loop as I suggested, or you would have seen that

The current must flow in the opposite direction within the battery to complete the loop

That is if we say outside the battery the current flows from positive to negative then

inside the battery the current must flow from negative to positive.

This is part of why I have always opposed explaining current as a flow of electrons in some form or other.

Further I commented that the conventional direction is simply a calculation model that fits in with the rest of theory about electrical effects.

My point is that I don't believe it...

I don't believe it either.

 

I'm sorry I guessed your name wrong, I hope no offence was taken.

I didn't say the above, and it's obvious you didn't try the loop as I suggested, or you would have seen that

The current must flow in the opposite direction within the battery to complete the loop

That is if we say outside the battery the current flows from positive to negative then

inside the battery the current must flow from negative to positive.

This is part of why I have always opposed explaining current as a flow of electrons in some form or other.

Further I commented that the conventional direction is simply a calculation model that fits in with the rest of theory about electrical effects.



I don't believe it either.

LOL, no offence taken at all. I used to own a business and my parter's name was Brian and I have been called Brian (and a few other things) most of my life. I actually did try the loop and I'm sorry if I offended you as well. The movement of current to me is similar to trying to explain how the earth began. We all have our own version of what really happened, truth is, we do not know 100% for sure. What we do know is that it flows and does work along the way. I find when my students ask which way it flows, there is always a large discussion on the topic. On motive power vehicles, you only need to know that it flows and performs great feats along the way and how you diagnose the problems that arise when electrons lose their way or start taking short cuts. The rest is way too deep for me. Sorry if I offended anybody else. I just find that some things should just remain simple. Life is complicated enough.

 

duplicate post

 

... I also just could not get my head around why the more positive terminal was the one that was effectively dangerous even though its where the electrons flow to....

What I dont believe is that the positive terminal of a circuit is anymore dangerous (to touch) than the negative terminal.

You seem to be implying that, and it is patently false...

Even the second part of your sentence is false. Current (Coulombs/sec) flows with equal magnitudes at either the positive or negative of any circuit. We can quibble about what is kind of charge carrier is moving, but what Current is (movement of charge) doesn't change...

 

What I dont believe is that the positive terminal of a circuit is anymore dangerous (to touch) than the negative terminal.

You seem to be implying that, and it is patently false...

Thanks Mike,

I am a "noob" so naturally I am going to make incorrect statements in an attempt to feel my way to a explanation.

Ok I can comprehend that -400V is just as dangerous as +400v. My original question related to 0v, but I think we have moved past that. I am going to stop thinking about electron flow in circuits. More of energy flow..

 

Positive safer than negative? Your fingers may not be able to differentiate but a simple NE-2 neon bulb seems a little calmer on one side than the other. Just a recent observation, not looking for additional arguments.

Left two are DC, right is AC

 

If you would use a faster shutter speed when you take picture, you would see that only one element(of the 3thd bulb)is lit at a time. They are alternating. They are not lit at the same time.

 

If you would use a faster shutter speed when you take picture, you would see that only one element(of the 3thd bulb)is lit at a time. They are alternating. They are not lit at the same time.

More proof that the undifferentiated filaments care.

 

All this theory stuff is great. But only us newbies really know the "truth". It's the smoke that makes it all work, let out the smoke and everything stops.

 

Hi,

First, i'd like to say that is a nice picture of the three neon bulbs. It's always nice to see first hand what something is doing and a picture is close to first hand. It also shows the results of an experiment that leaves less question about what is happening.

Given a single neon bulb and label the two elements A and B, when excited by the proper DC level lets say A glows and B doesnt. Reverse the polarity and B lights and A doesnt. Excite with AC and that's just like exciting with a DC level one way and then reversing the DC so the other lights, so first A lights, then B, then A, then B, etc., as the AC goes positive and negative without any other intervention.

But there are other possibilities here. Take the same bulb with elements A on the left and B on the right, excite with a DC level of appropriate value again, and say A again lights. Now reverse the BULB not the DC polarity so that B is now on the left, and now B lights
So the element connected to the correct polarity is the one that lights. You can perform this experiment to verify.

 

I think Discounting Vacuum tubes does a disservice to theory. Obviously there is current flow but no conduction between the elements so maybe electron flow is just the jostling of a potential? Charge state depends on when you 'look' at a point. < totally uneducated guess(swag).

 

Nowhere does either conventional or electron current theory discount vacuum tubes.

Also, if there is current flow there is conduction. Obviously. Look up the "Edison effect," the single scientific discovery from the mind of a great engineer.

(And yes I know "conventional current" is not a theory but an accounting method.)

 

Ha ha. This thread is funny.

It's difficult to get a clear picture with so many cooks making the soup. The different ways to look at electron flow are many. I think you need to pick one, simple model and study it until you understand it, then try reversing the logic in your mind and see how it works in the backwards point of view. When you get that to work for you, step to the next theory and see which details are now included that weren't in the first theory. Is it a wave? Is it a particle? That doesn't matter until you get the basics of a crude theory working for you. Then step up to what energy transfer really is.