Current flows [1] from positive to negative. Engineering and physics schools never taught anything else. The military and some trade schools taught electron flow, and may still. That confuses the hell out of the poor students.
"Hole flow" happens in semiconductors.
John
[1] the usual fatheads will get prissy about the phrase "current flows", of course.So, are they still teaching hole flow in electronics schools or are they back to electron flow?
Nicely self-referential!
The positive to negative convention was introduced by Benjamin Franklin a long time before electronics was invented or electrons were discovered.
John
Hole flow is still taught in semiconductor classes.
No. The terms are "pedants" and perhaps "pissy". And going back to basic physics, we always talked about electrons accelerating in a field and about charge per time. Since we were talking about the charge of electrons, I always got the impression that we were talking about negative to positive. The positive to negative convention was introduced in electroncs.
They are still teaching positive charge flow (=current), and that is what we always talk about.
Forget about electron flow unless you have some special reason to consider elementary particles movements or molecular chemistry in some special cases.
As numerous others noted, both are taught. Although there are comments about holes not really moving (each individual hole roughly stays put), the conduction in P material actually effectively takes place in the valence band, not the conduction band.
That's the reason P-channel devices are slower, incidentally (lower energy level).
All of this is part of quantum mechanics (and to quote Niels Bohr, as close as I can 'anyone not outraged on first hearing about quantum mechanics did not understand what has been said').
Cheers PeteS
For me in beginning physics, we talked about electric fields as pointing from a positive charge to negative charge, so that a positive test charge will feel a force pushing it towards the negative charge. This morphs into positive charges flowing out the positive side of a battery, the right rule giving you the right direction for the magnetic field set up by that positive current, and so on. You could just as easily talk about negative charges flowing the other way, and using a left hand rule instead. That is if I say 6A is flowing from the right side of your screen to the left, then that is either 6 A worth of positive charge is flowing from right to left, 6 A worth of negative charge flows from left to right. As the Circuits book I just finished they actually go to great pains to establish that being consistent when working a problem is the only thing that matters.
Hole flow is different, in that holes don't really flow in a semi-conductor, right. That is given a positive type semi-conductor there are holes in the atoms making up the material, and electrons hop in and out of the holes, the atoms being fixed in place, so the appearance is that holes are flowing the opposite way through the material. I never really had a formal electronics class (I always liked the AoE approach where you don't really care about the internals of the devices, but just how to make them useful), so maybe I'm wrong.
Craig
Moi? I just state it correctly. I don't think I get pissy about it, but I might point it out.
Someone mentioned that here and/or in an article on lightning.
Let me rephrase that. The positive to negative convention was introduced to *me* in electroncs ... *after* I learned that electrons flow from neg to pos which was years before I took physics.
^^ Hey, Me. You're Me ;)
Yup. My pre-physics knowlege of electronics probably caused me to favor the opposite view - a negatice charge being attracted to the positive charge. But remember, you don't need a negative charge for a positive one to set up a field or exert a force on another positive charge.
Yeah, but it doesn't hurt to talk pos to neg with others. That way we're always on the same sheet.
Right. They don't *really* move. It's just an unoccupied electron position. Holw flow is discussed as is their drift velocity. If you want a bit of fun learning, check out "The Britney Spears Guide to Semiconductor Physics." If you want the same thing on a paper plate, try MIT's open courseware. 6.021 Microelectronic Devices and Circuits
AoE serves its own purpose. The formal approach has it's own merits.
Ok. Me is Craig. How's that for ebonics? :)
Oh, of course. You're the only one who matters.
John
Except that Fluke won't sell you a negative-charge ammeter, and no engineer is going to keep you on the payroll for long if you keep getting the signs reversed.
John
Ok. It was introduced to me, perhaps you, and most likely others at some point in time after we started learning about electronics.
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