Is conventional flow a real, physical thing or is it something we still use for historical reasons?
• Electron flow is the actual current flow and the textbooks are the other way because of Benjamin Franklin.
• Conventional current is real and electrons just go the other way.
I know nothing about this and searching on the internet just made me even more confused.
Is conventional flow a real, physical thing or is it something we still use for historical reasons?
It's a model we use to describe flow of charge. "All models are flawed but some are useful" - and this one is very useful.
Electron flow is the actual current flow and the textbooks are the other way because of benjamin franklin ...
It is true that the mobile charges in metals are electrons but it is not always the case. In other situations the mobile charges are positive ions.
Don't get hung up on this. You don't need to think about electrons for most electronic engineering. Just volts, amperes, watts, ohms, henries and farads will get you a long way.
Give Benjamin some capital letters - even if you think he got it backwards.
The important concept is that current is the net flow of charges across some boundary. This is the basic physics of current. This is what you should remember.
Current flow is inherently directional. Early scientists could have defined the positive direction to be the other way, so that electron flow is the positive current flow direction. But they didn't. It is not a big deal. All the mathematics works just fine the way it is. It is not some tragic mistake. It does not mean that current is imaginary or made up.
Current also has a magnitude. The number of charges per second passing through the boundary. One coulomb of charge per second is one ampere (aka, 1 amp).
To sum up, current flow is very real. The magnitude is measured in coulombs per second (amperes) and by convention, the positive direction of current flow is opposite to the electron flow.
"Current" may be the flow of physical positive charge (protons or positive ions, for example) in one direction or physical negative charge in the other direction. It doesn't matter whether how we define "conventional current" as long as we are consistent.
While it's not wrong to consider conventional current as merely a bookkeeping trick, a more illuminating way of looking at conventional current flow comes from semiconductor theory. In solid-state devices, conventional current has a definite charge carrier, namely the hole. (A hole is a spot where an electron has gone AWOL from the semiconductor lattice, and can be created by the presence of a P-type dopant, or simply by random ionization.) This is quite important when working with semiconductors, especially when trying to understand minority-carrier phenomena, but can usefully be extended to metals as well.
Kind of made up and still being used for historical reasons. But the math doesn't care because in most cases it is symmetrical enough to work out. Like keeping track of how shadows move instead of how the light moves. Think of it as a book keeping trick...like negative dollars in accounting.
Paraphrasing my own answer to a similar question on Physics.SE:
Have you ever played the sliding 15 puzzle? There are fifteen sliding pieces, numbered 1 to 15, arranged in a 4x4 grid. It has one "hole" where there is no piece. You can move any piece adjacent to the hole into that space.
As you play the puzzle, which do your fingers actually move: the numbers, or the hole? Of course, your fingers only move the numbers. You don't actually touch the hole.
Does the previous question really matter? Would you get the same outcome if you actually moved the hole? Indeed, the game would exhibit the same behavior, even if it was the hole that actually moved.
Is it sometimes useful to think of the hole moving? Yes, it's an effective part of solving the puzzle. A skilled player can move the hole anywhere he wants, and can even move the hole around in a closed circuit. Even more important, a skilled player knows that there are times to think of the puzzle as moving the numbers, and other times when it is better to think of it as moving the hole.
So is the hole a real, physical thing? In some contexts, yes; in other contexts, no. Most of the time, it does not matter. Use the convention appropriate to the task.
It's also worth noting that electrons are not the only charge carriers:
Positive ions flow in the electrolyte of batteries and electrolytic capacitors.
In electrolysis, hydrogen fuel cells, and mitochondrial membranes, positive H+ ions move.
Positive charge can flow in semiconductors in the form of holes, which are more than just an absence of electrons, due to their different dispersion relation.
The ultimate answer to your question is that using the convention which is most useful to a given problem is more important than worrying about what physically represents the charge. Because like the 15-puzzle, the outcome will be the same.
Conventional current assumes that charges are positive and flow from from positive terminal of a voltage source to the negative terminal. Ammeters and semiconductors are setup to indicate conventional current. Put a positive voltage on a ammeter and it will indicate a forward current even thought the true physical current is in the opposite direction. Put a positive voltage on the arrow of a diode and it will conduct, but the true physical current direction of charge will flow away from the arrow. Conventional works well if one does not care about the physical direction of the current. It does away with spurious negative signs in calculations. If current direction is needed, a good method to use is to do your calculations assuming positive charges. If working with semiconductor holes or positive ions in electro-chemistry, do nothing because they are positive charges. If working with electrons, flip the physical direction.
