Why Does Electron Current Flow From Positive To Negative Terminal
Electric current is seen as a flow of positive charges from the positive terminal to the negative terminal. This choice of direction is purely conditional.
When electric current was earlier discovered, way back before anyone knew about electrons.
Benjamin Franklin, an American scientist and inventor, postulated that “electricity,” whatever it is, moves from the arbitrarily named positive pole of the battery to the negative pole in order to work.
Later, it was proved that it was the other way around – electrons tend to flow from the negative to the positive pole. Despite this new discovery, no one was willing to change the view of this flow, so it is still believed to move from + to -.
Current flowing from negative to positive is known to be conventional current, conventional current flows in the opposite direction to the direction of the negatively charged particles (electrons) and moves in the direction of the positively charged particles (holes).
The current flows from a high potential to a low potential, and we have a high potential of electrons collected at the positive pole and a low potential of electrons at the negative pole.
Thus, there must be a potential difference for the current to flow. Therefore, in a conductor for negatively charged particles, current flows from positive to the negative terminal and from negative to positive in the battery.
We know that electrons are negatively charged and thus, the conventional current flows in the direction opposite to the direction of electron motion.
Electron Ideaology In Conventional Current
Current is defined by the amount of electric charge passing through some surface per unit time.
Now comes the turn of electron flow and conventional current. It should be remembered that at the time when our first scientists investigated the power of electric current, it was not so well known what this thing, current, was and what it consisted of. People didn’t know that it was electrons carrying a charge. They knew it was something, but what it was, it wasn’t very clear.
So what they did was simple: They studied the macroscopic model. It was practical. If you want to use a battery, you don’t need to know how many electrons can go from one side to the other. It’s fine if you know, but it’s not practical knowledge. Instead, it’s much better to know that it can power, say, 3 amps for two hours until it discharges.
The concept of “electrical potential” has also been developed. It was logical to imagine that current would flow from places of higher potential to places of lower potential, so that’s how we determined the direction of the current.
When these two potentials equalize, the current flow stops. Thus, over time, circles of people concerned with electricity adopted the standard direction of current flow and went on to develop other useful things based on it.
In parallel with this, there were people who studied the microscopic world. Over time, they were able to figure out that you have carriers of electrical charge and that in metals they are usually electrons.
They also figured out that, say, in liquid solutions, you can have ions, which can also conduct current.
Over time it became clear that the flow of electrons is opposite to what the macroscopic scientists identified as the positive direction of the current, and so we got an “electron” current and a “conventional” current.
The macroscopic world worked to a level without actually understanding what was going on at a lower level.
As a result, the discovery of the sign of the charge of the electrons had no significant effect on the course of things in the overall picture of electricity.
So there was no urgent need to redefine the direction of current in traditional electrical engineering.
It just turned out that our electrons were moving in the opposite direction to what we thought, but everything else remained the same.
So it remained that the normal current flows from a place with a higher electric potential to a place with lower electric potential, but the actual flow of electrons moves in the opposite direction.