Conventional (current) flow is from + to -. It comes from early times when no one knew the charge of the current carriers and so they arbitrarily defined them as being positive.

But the current carriers turned out to be electrons, which are negatively charged, and since like charges repel and opposite charges attract, they are attracted to a plus terminal. Thus electrons flow from minus to plus.

The polarities are still correct. Electrons (- charge) flow from the - terminal of the battery through the circuit to + terminal of the battery.
Direction of Current
Electron Flow

When we say "current flows from + to -", we do NOT mean electron flow. We mean conventional current flow or "hole" flow. Do you know the concept of electrons and holes? We know positive charges come from protons and negative charges come from electrons. But we also know that protons do not flow since the proton is stuck in the nucleus, therefore positive charges do not physically flow. Electrons on the other hand, do flow since they can jump from atom to atom so negative charges can flow. But when the negative charge jumps, it leaves behind a "hole" of positive charge that originates from the proton in the nucleus which no longer has it's charge cancelled to zero because the electrons isn't there anymore. As the electrons move in one direction and leave behind holes, it will appear as though the holes flow in the opposite direction. This hole flow is conventional current.
Hole Flow

This is probably the worst legacy issue I hate about electronics, luckily it doesn't matter most of the time until you get into semiconductor physics.

You'll almost never see electron flow used, unless as you say you're a physicist.

In reality the electrons are following the blue arrows. Think about it this way, the polarity symbols indicate the type of charge carrier (an electron or a hole) that originates from the terminal. Electrons are negative, so they come out of the negative terminal following the blue line.

Exactly what the picture says. Perhaps if you put your confusion into words we clear up that particular confusion. I thought the picture was pretty obvious so we must be missing something from your train of thought

"Conventional flow" Is from + to -
"Electron flow" is from - to +

I'm just repeating what Parkinglotlust said, he was pretty clear. Why are you asking the question again?

I think you are confusing the fact that an electron is "something" but has a "negative" charge. Normally we are used to the idea of "something" flowing to an area of "nothing". In math this intuitively starts out as "positive" to "negative" since positive is more of something than negative.

BUt when electronics started out we weren't able to see what was "something" and what was "nothing" so we made an exectuve decision and labelled one positive and one negative without knowing for sure. It turns out we made a mistake and reversed the labels we are normally used to. So "something" which is labelled "negative" flows towards "nothing" which is labelled "positive". Positive and negative are purely mathematical labels, you could reverse everything and the meaning would not change.

It's a bit like knowing that dark and light exist, but not knowing whether empty space is normally dark or light, and whether it was dark beams darkening or light beams lighting. One has to be nothing, one has to be something, but you're not sure which. If you were sure, you would give "something" the label positive and the "nothing" negative. If you weren't sure but had no choice, you just give randomly give them a label and hope you're right. We were not right in this case.

Did you read the 3 links I sent you? Or more importantly, look at the animations?

Originally Posted by dknguyen

This is probably the worst legacy issue I hate about electronics,

I've heard that we have Ben Franklin to thank for this. You know, he was really amazing and did so many great things in his life. But, apparently he wasn't much of a gambler. He had a 50% chance and he got it wrong!

I'll bet there exists a parallel universe made of antimatter with positrons flowing in conductors. I wonder, did the people there define it the opposite way, and get it wrong too?

EDIT: I have been replying to posts but keep getting a "message will be checked by moderators" message which is making it hard to have a conversation!


dknguyen, this is the 3rd time I've tried to thank you. I think you have hit the nail on the head in the flaw in my understanding. That being the notion of charge flow is not the same as electron flow!

Originally Posted by dknguyen

In reality the electrons are following the blue arrows. Think about it this way, the polarity symbols indicate the type of charge carrier (an electron or a hole) that originates from the terminal. Electrons are negative, so they come out of the negative terminal following the blue line.

Exactly what the picture says. Perhaps if you put your confusion into words we clear up that particular confusion. I thought the picture was pretty obvious so we must be missing something from your train of thought

My confusion is like this:

When I look at a schematic to try and figure out what is going on I imagine a physical flow of electrons running through a circuit from the positive terminal of the battery to the negative terminal of a battery.

From what you have said I am now getting the idea that this is wrong regarding the flow of electrons. But that it's correct to think of a more abstract notion of a "charge" flowing from the + to - terminals?

My electronics interest is in guitar amplifiers and effects. When polarized components such as diodes, capacitors, transistors and electron tubes are thrown in to the circuit it just confuses me.

For example, if I'm understanding what your saying then is this correct:

If you have a diode in a circuit a "charge" will be flowing from the + to - side but the actual electrons will be flowing from the - to + side?

Originally Posted by electric_n00b

My confusion is like this:

When I look at a schematic to try and figure out what is going on I imagine a physical flow of electrons running through a circuit from the positive terminal of the battery to the negative terminal of a battery.

From what you have said I am now getting the idea that this is wrong regarding the flow of electrons. But that it's correct to think of a more abstract notion of a "charge" flowing from the + to - terminals?

No abstract notion is needed if you understand the difference between the appearance of something flowing and the fact that something physically is flowing. Your notion of charge in this case is holes which occur because of the positive charge of protons in the atom's nucleus, but the protons are not moving themselves because they are stuck in the nucleus. BUt the positive they generate *appears* to be flowing in the opposite direction of the electrons which cancel out their positive charge as they moving. See the 3 links I provided in my first post. THey provide more details and graphics.

Originally Posted by electric_n00b

If you have a diode in a circuit a "charge" will be flowing from the + to - side but the actual electrons will be flowing from the - to + side?

Correct. YOur difficulty arises from your association with "positive" as something and "negative" as nothing (see my previous post).

electric noob, you have the totally wrong idea of how electron flow occurs at all. It takes minutes, hours, months, even years for a single electron to actually move from one end of a circuit to the other in a metal, and in the case of AC circuits the electrons don't actually move at all on average, what moves is the energy. Far too often people think of electronics as water flowing from one point to another, which it absolutely is not. It's energy (like a wave in water) traveling from one point to another, with electronics electrons are the media, what is being 'transferred' is energy.

Read this page
SCIENCE HOBBYIST: how transistor works, an alternate viewpoint
It's a lot to take in but explains it all.