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Why does current flow the opposite way from the electrons?

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Re: Why does current flow the opposite way from the electrons?

#161

Post by utensil4778 »

B1FF_PSUVM wrote: post #113
a1445c8b wrote: post #73

Earlier quoted context omitted.

Using the word “accumulator” wouldn’t be enough to differentiate batteries from capacitors, inductors, etc. which are also accumulators.

> inductors, etc. which are also accumulators. In what sense do inductors accumulate? Batteries and capacitors accumulate (i.e. integrate) current. Inductors differentiate current: v = L di/dt means you get voltage out of current changes.

The main way that inductors function is by storing energy in a magnetic field, exactly analogous to the way capacitors store energy in an electric field.

Re: Why does current flow the opposite way from the electrons?

#162

Post by utensil4778 »

denton-scratch wrote: post #146
pdonis wrote: post #32

Earlier quoted context omitted.

> there is no way of knowing the direction of the charge But there is--otherwise we wouldn't know that Franklin got it backwards. He thought the charge carriers were going one way, and chose the convention he did because he thought it matched the way the charge carriers were going, but it turns out they were going the other way. The signs of the charges are a convention--and the fact that we still use Franklin's conv…

> but it turns out they were going the other way Nobody seems to have mentioned Holes. Holes are positive charge-carriers. Yeah - they're virtual, they're not like positrons or protons. But they behave just like electrons going "the other way". My understanding is that a hole represents the absence of an electron. If an electron is removed (e.g. by rubbing), there's remains a physical object bearing a positive charge…

The concept of holes is important, but it doesn't have much practical use. It typically only comes up when you're discussing the physics of how semiconductors work, or doing similar electron-level analysis of a component.

It's also usually brought up early on when teaching new students about circuit physics, but it's really not something that comes up in an EE's day to day.

Maybe it's more relevant if you're deep into analog or RF black magic, I wouldn't know.

Re: Why does current flow the opposite way from the electrons?

#163

Post by MarcScott »

I fondly remember watching kids in physics exams trying to answer questions using Felming's left hand rule. (https://en.wikipedia.org/wiki/Fleming's_left-hand_rule_for_m...

You could watch them hold up both hands, wondering which one to use, then trying to dislocate their wrists as they aligned fingers and thumb with the diagram on the exam paper.

Re: Why does current flow the opposite way from the electrons?

#165

Post by bithive123 »

adrian_b wrote: post #125
throwway120385 wrote: post #13

Because he didn't know anything about electrons, and the experiment he did involving rubbing amber and glass rods on fur and silk cloth only showed that something was transferred between the two materials, and that when the material containing the substance was brought near to the other material containing the other substance, the property conferred by the substances appeared to negate. If you read Teaching Introduct…

The reason why which charge is named positive and which is named negative does not matter is because in all the equations that relate electric charge with other measurable physical quantities we never have an electric charge alone, but we always have the product of two electric charges. The value of the product of two electric charges is invariant to the convention chosen for the sign of the electric charge. Numbers…

Negation, being a concept, exists only in the mind. Same with "things". A thing is a noun; a part of speech. The "real world" is undifferentiated quanta.

Re: Why does current flow the opposite way from the electrons?

#166

Post by dboreham »

MarcScott wrote: post #163

I fondly remember watching kids in physics exams trying to answer questions using Felming's left hand rule. ( https://en.wikipedia.org/wiki/Fleming's_left-hand_rule_for_m... You could watch them hold up both hands, wondering which one to use, then trying to dislocate their wrists as they aligned fingers and thumb with the diagram on the exam paper.

Always use Maxwell's corkscrew rule.

Re: Why does current flow the opposite way from the electrons?

#167

Post by philipov »

mr_mitm wrote: post #131
philipov wrote: post #105

Earlier quoted context omitted.

> We could just as easily have called it "black" or "white" charge And when we found a charge system that had 3 charges rather than just two, we did .

It's either six vs two, or three vs one, depending on what you mean by charge. The quarks and gluons can be red, blue, green, antired, antiblue, or antigreen.

I was hoping someone would catch that ;)

Re: Why does current flow the opposite way from the electrons?

#168

Post by denton-scratch »

im3w1l wrote: post #159
denton-scratch wrote: post #152

Earlier quoted context omitted.

Your hole-gun idea left me scratching my head. An electron gun produces a beam that contains only electrons; there is no conductor, and I think holes can exist only in the presence of a conductor. So you can't shoot a beam of holes through a vacuum. But if the material between the gun and the screen were a semiconductor, maybe you could draw pictures on the screen using a beam of holes? I mean, I don't see why a beam…

> I mean, I don't see why a beam of holes can't be focused just like a beam of electrons. Wouldn't electrons rush in to fill the holes from every direction, rather than just the intended one? That's what my intuition says anyway. So yeah, my guess would be that it is in fact not possible.

That blade cuts both ways; the electron beam in a CRT travels through a vacuum, there's nothing to "rush in". A hole beam would have to travel through a medium with no free electrons.

Re: Why does current flow the opposite way from the electrons?

#169

Post by joquarky »

bithive123 wrote: post #165
adrian_b wrote: post #125

Earlier quoted context omitted.

The reason why which charge is named positive and which is named negative does not matter is because in all the equations that relate electric charge with other measurable physical quantities we never have an electric charge alone, but we always have the product of two electric charges. The value of the product of two electric charges is invariant to the convention chosen for the sign of the electric charge. Numbers…

Negation, being a concept, exists only in the mind. Same with "things". A thing is a noun; a part of speech. The "real world" is undifferentiated quanta.

Put simply, "the map is not the territory"

Re: Why does current flow the opposite way from the electrons?

#170

Post by cdelsolar »

card_zero wrote: post #92
a1445c8b wrote: post #75

Earlier quoted context omitted.

> Hmm. "We rub our Tubes with Buck Skin", he says in the same letter. My immature brain didn’t get past this sentence.

He was merely investigating what happen if persons touch one another after exciting the tube, on or off wax.

Lol
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