I appreciate all the replies to my comment about the direction of current
flow (which I have ALWAYS thought of as the direction that electrons flow).
My comments below.
Ben Franklin had a 50-50 chance of getting it right and he had an unlucky
>> day. It is too bad that he did not make the opposite choice.
>>
>
> Ol' Ben was just ahead of his time coming up with a way to trace
> semiconductor circuits even before the vacuum tube.
> 73 Roger (K8RI)
>
EEs have used conventional current since there have been EEs and it was
> defined by Ben Franklin.
>
They aren't so bad, but I've always found electron flow easier to explain
> to students. Electron flow is real, while conventional current is a
> convenience "at times."
>
> sometimes I fell like Ben, given a 50-50 chance I always get it wrong.
> Bill
>
I happen to make my living by manufacturing mostly HV corona-discharge
negative room air ionizers (www.negativeiongenerators.com). I know all too
well about Ben Franklin getting "negative" wrong many moons ago. We have to
explain to potential customers on a regular basis why negative ions are
actually a positive thing and actually have an extra electron and not the
other way around. Sometimes we succeed. :-)
> From: "Jim Garland" <4cx250b@miamioh.edu>
> Date: Wed, 28 Aug 2013 18:03:55 -0600
> Subject: Re: [Amps] Hole Flow
> Sorry guys, but I can't resist ... I hope you'll forgive me for
> pontificating a bit.
>
I'm very glad you did, Jim!
I have enjoyed reading your posts and articles for many years. I've
never seen any amplifiers built any better that the ones you've built in
the magazines, etc. and that's what I think of whenever I see a post from
Jim Garland. :-)
> In science, there are often several ways to skin a cat.
> But then quantum mechanics came in and saved the day. ... The wave
> desciption is much more convenient and easy to use than the more "correct"
> particle description.
> And the same situation applies to electron transport in a vacuum
> tube or hole transport in a semiconductor junction. Whatever works and is
> easiest to use is the best way to analyze the situation. In a cathode ray
> tube, electrons go from the cathode to a fluorescent screen and are
> deflected by a magnetic field. We would be nuts to try and articulate that
> process in terms of current flowing from the fluorescent screen to the
> cathode, although in principle we could do so. Similarly, in a vacuum
> tube,
> if you're interested in how the space charge builds up, it's best to think
> about negatively charged electrons. In a P-channel MOSFET, or a particle
> accelerator (which accelerates protons), you'd best think about holes and
> positive charges.
>
I will try and understand that last point.
> Now here's the key point. Whatever description we choose, we have
> to
> be self consistent, or eventually we'll get hopelessly confused. So even
> though we know plate current in a vacuum tube is carried by negative
> electrons, electrical engineers always speak of the current in an operating
> vacuum tube circuit as flowing from the plate to the cathode, i.e., from
> positive to negative. They do that because the actual sign of the charged
> particles (electrons) doesn't matter from the point of view of the circuit
> explanation.
Hmmmm. Okay.
> If they described the current in the vacuum tube as flowing
> from the cathode to the plate, then to be consistent they would have to
> describe the current from the power supply as flowing into the positive
> terminal of the power supply.. They could do that, and it wouldn't
> technically be wrong, but it would be confusing, ...
>
Personally, it would be very confusing to me to think of it any other way.
I learned from a reading a number of books since I was a boy. Library
books, ARRL publications, college physics books, and I don't know what all.
Those books showed tubes in the power supply such as the 5Y3 and 5U4, and
it was --and still is-- very natural for me to think of the electron flow
flowing from the powered device to the positive PS terminal connected to
the cathode of the tube.
> The little arrow in an NPN or
> PNP transistor symbol points toward the direction of current flow (positive
> to negative) as does the arrow in a diode symbol. It's just a convention,
> and it could been chosen differently, but it's a universally accepted
> convention. If someone bucks the convention, and does everything
> backwards,
>
I have *always* read that the diode symbol was actually representing the
catwhisker "pointing towards" and contacting the galena crystal (or
silicon, germanium, carborundum, iron pyrites, etc.) , for lack of a better
expression. Others in this thread expressed it similarly and better than I
just did.
> it's not that they're wrong, but they're going to have a lot of trouble
> communicating with other people without causing confusion. So the
> convention, accepted by virtually all electrical engineers and scientists
> in
> the world, is that current flows from positive to negative, no matter what
> particular particle (proton, electron, hole, ion) carries the current.
> Remember that electric currrent is a statistical quantity, like ... So
> while it may seem
> non-intuitive, individual electrons in a vacuum tube flow from the cathode
> to the plate, but the universal convention is that current in a vacuum tube
> flows the other.way. Sorry, but that's the way it is.
> 73,
> Jim Garland W8ZR
>
Your points are well taken. I am not exactly disagreeing with you, but I
just have never looked at it that way, and I've done a lot of reading over
the years. Having said that, I most certainly do appreciate your thoughts
above, Jim, and would welcome any further comments you might have.
73, Mike
www.w0btu.com
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