[R-390] The "Current Direction" discussion...

[Clay Nicolsen]

Well, I'll toss in my dos centavos, fwiw!

Back in the day, before the military thing got in the way, I was a EE student.  
Now that I have some free time on my hands, I'm taking electronic circuit analysis courses at the local college, so I'm right back in the middle of this topic!

While I do have some personal angst over the fact that teaching electronics using "Conventional Current" is bass-ackwards from the real current flow, I certainly understand why it's taught that way.  It's not at all intuitive to think that current flows from negative to positive, because negative is "less" than positive, so it's kind of like thinking that current flows from a "more less" point to a "less less" point!  And a lot of folks have a hard time imagining electricity "boiling up" out of a ground!  Of course, an electrical ground may be above or below an earth ground, so there's another problem...  Finally, if you assume that current flows from positive to negative, the arithmetic gets so much simpler.

The reason that "holes" were invented was to allow students to imagine "something" that actually flows from positive to negative.  There aren't really any such things, of course, as far as actually existing in the real world.  We just all agree to pretend the same thing.  There are no physical objects that move in the opposite direction of electron movement, like checkers jumping each other on a checker board.  A hole is simply "A spot where an electron is not."  If there's a "spot where an electron is not", then we have a spot where an electron can move to.  Jay's explanation:

"Holes are atoms that are lacking electrons in there outer "ring" thus 
the atom has a net + charge.A vacuum does not have a charge.
 Jay"

is partially correct, in that an atom that's missing one outer energy band electron does have a net positive charge, but it's not correct to call that atom a "hole" because in conventional current methodology holes "move", and an atom NEVER moves.  As one electron leaves, that leaves a "hole" where a different electron can reside, for a fraction of a second, until it moves on to another atom, leaving a fresh "hole" behind where another electron can jump in.  So, if you can visualize the electrons jumping from spot to spot, then you can also visualize what appears to be a single spot jumping in the reverse direction...sorta.

I finally just adjusted my head to simply believe that "current" (forget whether or not that has anything to do with electrons!) flows from positive to negative, and I just forget about the rest.  It's much less stressful! ;)  If you're having a discussion about electron movement through PN junctions in a transistor, or about electron movement through the grid to the plate, then just talk about the electrons and forget about "current".