Its like Bill Gates trying to get through an entire football team, and sacking the quaterback.
Nerds powah! :grin:
Posted on 2003-04-10 01:40:51 by Maverick

Hi NaN,
a question for you, if you don't mind. :)

How do you visualize in your mind the physical phenomenon of electric current?

As example, let's take a battery or a charged capacitor.

In my mind I imagine two pieces of copper (the positive and negative pins), one more densely populated of electrons (the negative pin), and one instead having less electrons than it would have at rest (i.e. a dead, detatched copper wire).
Can you correct it, please?

For example.. given the average number of free electrons per gram of copper wire, if we apply a difference of potential (voltage), will it result in:

# the negative pole having more electrons than the "rest value", and the positive having less than the "rest value"

or:

# the negative pole having more electrons than the "rest value", and the positive having the "rest value"

or maybe it's completely another way?

If instead is one of the two above.. is there any physical limit to the amount of difference of density of free electrons that a copper wire can have at rest vs at a top maximum or minimum? If yes, what is it?

Keep the great work pal! And sorry for the questions.. but I tend to prefer to visualize things that way in my mind. :)
Posted on 2003-04-10 01:41:38 by Maverick
Nan,

Just a question. It is known that electrons move from negative to positive, but why is it in the circuits, we seem to think that electrons move from positive to negative (conventional current they call it). This puzzled me seriously.
Posted on 2003-04-10 05:29:48 by roticv

Nan,

Just a question. It is known that electrons move from negative to positive, but why is it in the circuits, we seem to think that electrons move from positive to negative (conventional current they call it). This puzzled me seriously.


uhmm... dont remember why i'm disputing that thing long ago. maybe because besides electron, there is something called 'hole', so when the electron goes from - to +, the hole was reversed. its too theoritic and atomic, and... physicyan field.
Posted on 2003-04-10 05:44:28 by dion
Maverick,

I usually try to visualize electrical flow to water flow using pressure, pipes and diaphragms as my tools. Some may think it silly, but it works in most instances for me.

For instance, water pressure is easily understandable. This equates to voltage.

Flow rate equates to current.

Resistance would equate to pipe flow restrictions.

A diaphragm allows for storing kinetic energy as in capacitance. It's also useful for visualizing how a transistor works if you allow the diaphragm to control a flow restrictor.

A tube with a heavy spiral wheel resists changes to the kinetic energy of the spiral. This would equate to reactance in coils.

It's not perfect, but it works for me. Please accept it for what it is. A toy to use for visualizing electronic action. I feel you may confuse yourself when you try to account for electron density (or water density) or less than/greater than picturizations. There really isn't a pooling up of electrons at one end or another. The electron force is exuded throughout the entire circuit in much the same way as water pressure is equal - allowing for resistances.

I always visualize water flow in the direction of electron flow. I ignore hole flow theory (positive to negative) completely. As it isn't pertinent to the currently accepted electrical theory. Positive to negative flow was the originally accepted theory in the beginning. It was found to be untrue later. The conventions of positive and negative were kept.
Posted on 2003-04-10 14:15:43 by Kdr Kane

Hi Kdr,
that is a good way I've already used.. but I find that ones of its limits, intuitio-wise, is that if you break a water tube the water flows freely (even from only one conductor!), while for electricity it's a very different thing.

But in general, taking into account its limits, it's a very good method to visualize things.
Posted on 2003-04-10 16:03:07 by Maverick

Just a question. It is known that electrons move from negative to positive, but why is it in the circuits, we seem to think that electrons move from positive to negative (conventional current they call it). This puzzled me seriously.
Actually, conventional current flow is the flow of positive charges, not the negatively charged electrons.
Posted on 2003-04-10 16:57:58 by tenkey
Today, Conventional Current is known as the flow of "holes". I believe the origins of Positive Current stem from Ben Franklin.

One note about electron flow. Electrons flow about 11 inches a second. But if you imagine rubber balls lined up in a tube, and you push one, the force is transfered rather rapidly. Since electrons repel eachother, when they are in a 'tube', they line up along the sides. Very few actually travel through the middle of the conductor.
Posted on 2003-04-11 03:52:52 by eet_1024
Very few actually travel through the middle of the conductor


at very very high frequencies, they don't travel at all at the middle!! they travel at the edges of the conductor, and it's as if you can remove the middle part of the conductor and make it a tube. This is known as "skin effect".
Posted on 2003-04-11 11:37:17 by flotsam
True, but we weren't discussing RF theory (feel free to start a new thread on that freaky subject).

Say hi to jetsam
Posted on 2003-04-12 02:23:36 by eet_1024
Yes I know it's not what you're discussing, but I'm just adding some weird behaviors of electrons.

Say hi to jetsam

he drowned :grin:
Posted on 2003-04-12 13:04:14 by flotsam