Arceus74 said:
1)First of all why does electricity flow in the opposite direction to electron flow?
2)What is electricity in relation with a electron?
sophiecentaur said:
As dave has said, the direction of flow of Electric Charge is the direction of the Current. It just happens that the (recently discovered) electron is what carries the charge in metal wires. A negative charge flowing one way is the same as a positive charge flowing the other. There needs to be no confusion and certainly no-one "got it wrong" as students love to say. Forget about electrons in everyday electronics discussions
rumborak said:
@sophiecentaur , I don't know what the purpose of your endless tirades is on this forum about how to "properly" learn. People ask questions here, and there is no cookie cutter approach to how to enlighten somebody.
Questions of manners aside, I have to side with
@sophiecentaur here. We could get some more EE's in the room and I think they would agree relative to the subject matter. In particular I agree very much with
comment #7 that too often, simplistic notions of electromagnetism are taught in our schools (certainly in U.S. schools) in which mechanical metaphors are used in place of the more scientific but also more abstruse conceptions offered by physics. Since this is a physics web site, it would seem appropriate not to offer up the mechanical metaphors in response to the OP's question.
I should clarify that I'm not an EE myself; however the reading I've done over the past 3 years has made it pretty clear how easy it is for even good students to learn mistaken concepts when taught outside of a physics framework or outside of the relatively few good presentations of electronics as a craft.
There is an excellent book available, written by a UK-based EE, Merlin Blencowe, about valve-based audio amplification circuits for electric guitars; the first chapter is something of a primer about various concepts in electronics; and at a certain point early on, he includes a lengthy footnote about misconceptions to do with "current" in particular. It's just a footnote, but it's worth reading, as he lays out clearly the distinction between why it's useful at times to speak of current "flowing" vs. the fact that this is only a metaphor, and doesn't quite jibe with actual math-based physics models. The book is
Designing Tube Preamps for Guitar and Bass, and here's a link to the
first chapter as a PDF; the footnote can be found on p. 3.
Here's the text in the main body of the chapter that leads to the footnote, which is marked with an asterisk:
New electrons continue to boil off the cathode to keep the space charge topped up, so altogether we have a net transferral of negative charge from cathode to anode. If we reckon current as flowing from cathode to anode then it must also be negative, but since most people prefer to work with positive numbers it is easier to say that a positive current flows from anode to cathode, as this amounts to exactly the same thing.*
And here's the first few paragraphs of the footnote, just to whet the appetite for reading the whole thing:
* This sometimes causes consternation among students who argue that conventional current ‘goes in the wrong direction’, but this arises due to a misunderstanding of what current actually is. The confusion is understandable because we often describe current as being a flow of electrons, and immediately form a convenient mental picture of what is happening inside conductors. But while this explanation is good enough for everyday conversation, it is not the whole truth.
Strictly speaking, current does not have any direction in the usual sense because it is not a physical ‘stuff’ that moves around a circuit. Current is more properly defined as the rate of change of electric flux: ##i = dQ/dt##, and is, therefore, an entirely mathematical concept. Current is a scalar quantity; it has no direction, only sign (positive or negative).
The misunderstanding is further compounded by the limitations of the English language which was never designed to cope with the peculiarities of quantum physics. The word current actually means the same thing as flow, and does not imply a particular direction, yet it is standard practice to describe circuits using phrases like “current flows from A to B”, when technically this is nonsense.
Also helpful (if a bit ranty at points) is a series of articles by
William J. Beaty, an engineer, in which he tries to point out typical misconceptions about how EM is taught, versus more accurate representations arising out of physics; here's a page with an index to the articles:
MISCONCEPTIONS SPREAD BY K-6 TEXTBOOKS: 'ELECTRICITY'