Last Updated on March 7, 2020 by Krunal Shah (Mod)
Let me make you understand what is current in electricity.
Voltage exerts force on free electrons to move. Current is movement of free electrons through a conductor.
Why the unit of Current is Ampere?
Now, this is quite interesting to know.
The number of electrons passing through a cross-section of a conductor in one second determines the amount of current flowing. Due to the very small size of atoms, it takes about 1024 electrons to fill one cubic centimeter of a copper conductor. Thus, it would be very difficult to represent the current in terms of electrons.
That is why the unit of current is Ampere.
A current of one-ampere means, in one second 6.24 X 1018 electrons move through a cross-section of a conductor.
The direction of the Current flow
The direction of the current flowing has two different theories:
- Conventional Flow theory
- Electron Flow theory
This theory states that electrons flow from positive to negative. Benjamin Franklin theorized this when very little was known about electricity. It states that an invisible fluid known as electricity tended to flow through a wire from the positive to the negative. Ben’s theory became the convention (hence the term “conventional current”) in electrical theory, mathematics, textbooks, and electrical equipment for the next hundred years.
This theory states that electrons flow from negative to positive. More research carried out on the behavior of electrons. Scientists discovered that electrons actually flow from negative to positive. Since electrons are negatively charged, it is attracted towards positively charged bodies and repelled by negatively charged bodies.
Understanding Current with a Water Tank analogy
Imagine a water tank over the roof of a residential house. Water flows from the tank to the tap through the pipe. In a similar manner, in an electric circuit, due to the force of voltage, free electrons inside the conductor starts moving. So current is nothing but the movement of electrons flowing through the conductor.
We can say in short that, the current is ‘flow of electrons’ in an electric circuit.