<This is not a flame>
Kinda reminds me of the saying,, "Engineers can't solder." In other words it's
the technicians in the real world that know how the stuff works and can really
build something. There are people who learn all the math behind something but
never really built anything but still think they are knowledgeable in the area.
I've done a bit of tinkering like building a little tri 811a grounded grid
linear
amp for 80 meters for my yaesu rig. I knew the theory of how things were
supposed
to work and I put it together. I haven't a clue as to how to do the math behind
it but I think it's obvious that that's not important, as neither did 90 percent
of the early radio "engineers" who were simply 12 to 17 year old kids! Quite
frankly even the various incarnations of ohms law drive me nuts, because I never
have the "other" figure to plug into the formula. Trial and error worked out a
lot better,, kinda why they invented decade resistance and capacitance boxes!
:))
I don't hold a high regard for systems of teaching that attempt to explain
everything in mathematical terms and completely leave out the hands on practical
REAL WORLD approach which is a heck of a lot easier to learn and makes more
sense.
Dan
"George, W5YR" wrote:
> Actually, the notion of "current flow" began when folks started
> analyzing circuits and applying well-known circuit laws. To an engineer,
> "current" is a mathematical entity and its use, etc. in a circuit model
> has nothing whatever to do with the physics of how the actual
> electrical current is being conveyed in the circuit through various
> device and circuit elements. The circuit laws applying to currents,
> voltages, etc. in the circuit do not concern themselves with the
> physical mechanisms of current, per se or of the devices in the circuit.
>
> Thus, when other folks - historically, the "technicians" - start looking
> into circuits and analyzing and applying circuit laws, they are confused
> by the seeming nonsense and inconsistency of the engineer's insistance
> on using a current definition that has "current" flowing in a
> vacuum-tube circuit such that it enters the anode (plate) and exits the
> cathode! Since "everyone knows" that a vacuum tube operates on an
> electron flow within the device, from cathode to anode, the engineer's
> analysis seems totally in error and at odds with Nature. "THE LOGIC DOES
> NOT WORK."
>
> But, the key point is that the engineer DOES get the correct answers
> when analyzing the circuit. And that is why to this day that formal
> circuit analysis and modelling techniques assign the direction of
> "conventional current" flow as being from + to - of the source of
> electrical energy within a circuit. A positive voltage rise is the
> voltage across a device from its negative terminal to its positive
> terminal, polarities being taken in accordance with the assigned
> direction of conventional current flow. All other circuit definitions
> follow accordingly.
>
> This is not a matter of sematics nor is it some sort of schoolboy battle
> of wits between the "engineers" and the "technicians." It is a
> fundamental aspect of circuit analysis that has served well for probably
> the better part of 100 years now. It has survived from the earliest days
> of electricity to the modern days of semiconductor devices. Just keep in
> mind that "current" can be a mathematical entity having nothing to do
> with actual physical mechanisms and nothing is lost in using it that
> way.
>
> Sorry if this turned into a sermon, but I would hate to see the list
> cluttered up - one more time! - with a current-flow vs electron-flow
> "discussion." Kinda like those "voltage decibels" that we hear about
> from time to time. <:}
>
> 72/73, George W5YR - the Yellow Rose of Texas NETXQRP 6
> Fairview, TX 30 mi NE Dallas in Collin county QRP-L 1373
> Amateur Radio W5YR, in the 55th year and it just keeps getting better!
> Icom IC-756 PRO #02121 (9/00) Kachina #91900556 (12/99) IC-765 (6/90)
>
> Dan Cox wrote:
> >
> > hehe, it's really amazing that the myth ever got started. Supposedly it was
> > easier around the turn of the century to explain electricity if you
> > explained it in the reverse of how it actually works.. Imagine these
> > people's confusion when they started learning about vacuum tubes for
> > instance! The logic just DOES NOT work!!
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