Confused

[IanB]

I'm fourteen years old,  I only started learning this stuff one year ago...  I'm not a troll!

OK then.

He decided that electricity flows from + to -.  Now, when I look at a diode or circuit diagram, I never know if the person is writing it under the assumption that Thomas Edison is right, or if they are basing their info on fact.

But this is where your problem lies. You are thinking that current flowing from + to - is not a fact, you are thinking that it is wrong.

You must not think this way. It is absolutely the case that electric current flows from + to -. It is how physics and engineering defines electric current. It is how everyone designs electric circuits and does their calculations. It is how you will do things in school and in college when you study physics and engineering.

If you follow the convention that everyone abides by, you will find it works just fine.

[wraper]

Electric current (carriers) not necessarily flows from minus to plus. Carriers can be positive and negative ions as well, not only negatively charged electrons. In such a case (electrolyte) positive ions move in the opposite direction to what you would expect from electrons. In plasma, current is carried by electrons and ions at the same time. So just stick with conventional current because "electron current" in not applicable in every situation at all.

[Nerull]

Electric current (carriers) not necessarily flows from minus to plus. Carriers can be positive and negative ions as well, not only negatively charged electrons. In such a case (electrolyte) positive ions move in the opposite direction to what you would expect from electrons. In plasma, current is carried by electrons and ions at the same time. So just stick with conventional current because "electron current" in not applicable in every situation at all.

This is often forgotten in these discussions. Electrons are not the only charge carrier, and different charge carriers can move in different directions, so if you try to use the direction your charge carrier is moving as the direction of current flow, it will change depending on what your conductor is. Conventional current is independent of charge carrier, and so is always consistent.

[hamster_nz]

It might be just me, but I find the whole idea of holes flowing to be fundamentally silly (no matter how useful it is as a conceptual model). It is akin to the empty bit of road flows in a traffic jam, in the opposite direction to the traffic flow. Although you can point and go "the hole is here", "and now it is here", "and now it is here" it isn't the same hole.

But then again, electrons in a current don't actually travel that fast either...with a 3 A current in a 1 mm copper wire, the electrons move at ?0.00028 m/s, taking an hour for the average electron to move 1 meter.

[Brumby]

As you can see, discussion on the subject brings out a variety of opinions and different points of view.  Sometimes you will encounter things that are obscure, misleading but often the discussion simply gets more confusing, especially for someone just getting into electronics.

A repost I know, but stick with this until you're ready to get into the detailed physics (which includes actual electron flow).  Even when you are ready, don't bother unless you know you have to.  It's not needed for the vast majority of electronics.

He decided that electricity flows from + to -.  Now, when I look at a diode or circuit diagram, I never know if the person is writing it under the assumption that Thomas Edison is right, or if they are basing their info on fact.

It would be fairly safe to assume they are talking about conventional current flow - that is from positive to negative.  That's how diode and transistor symbols have evolved and the general discussion of circuits follows this convention.

Anybody who wishes to present their discussion based on the reverse (actual electron flow) would usually make it rather clear that this is what they are doing, since conventional current flow is the norm.  Also, they are more than likely give their reasons for doing so.

Then there are those who are just being plain pedantic - and while they may be technically correct, in most practical applications people will either roll their eyes (if they realise what's being said) or get confused (if they don't).


In short - just stick with the idea that current flows from + to -  because it works.

[Nerull]

Who said anything about holes?

In electrolytic solutions, such as salt water, the charge carriers are entire atoms, and they don't move from negative to positive. In proton conductors, seen in some fuel cells (and ice), H+ atoms carry the charges, and they don't even have electrons.

And frankly, deciding something can't work because it doesn't make sense in a poor analogy is kind of silly. Anolgoies are useful tools for understanding, but its important not to confuse the analogy for the real process. Electrons are not cars driving down a road.

Just stick to conventional current. Every data sheet, and every circuit, you will ever see will be in conventional current.

If you're working on a device, like semiconductors, where you need to worry about the behavior of electrons in the circuit, you should already know enough about the fundamental processes that it isn't confusing anymore. If you're not working on those devices, it will never matter to you.

[hamster_nz]

Who said anything about holes?

AF6LJ did, back on the first page....

And frankly, deciding something can't work because it doesn't make sense in a poor analogy is kind of silly.

I never said it didn't work - just that it seems a little silly to me. Hey, but that is quasiparticles for you...