Basics of Voltage & Current | Easiest explanation

• June 2, 2020
• Gaurav J

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In this tutorial, we’ll learn about the very basic concept of voltage and current. In the previous tutorial, we have seen that we need some imbalance to provoke the electrons. Now the question is, the imbalance, is it the concept of voltage? And the flow of electron, is it the concept of current? Let’s get the answers of these question in this tutorial. 

Before getting started with the basics of voltage and current, I would recommend you to go through the previous tutorial on Static Electricity, as it will help you to understand the concepts more easily. 

What is Voltage ?

Let’s say you have a box in your room, and you need to move that box to your main hall. To do that you will need some energy, right? By using energy, you moved that box from your room to your main hall successfully.

Box was already there in your room, but to move it from your room to your main hall you had to apply some energy to it.

The concept of voltage and current is not much different from the concept of moving a box from your room to main hall.

The box is already there; the electrons are already there, you need a force to move that box; you need a force to move electrons, and that force required to move the electrons from one place to another is called as voltage.

Voltage is the force required to move electrons from one place to the another. 

So, when we rub glass rod with Silk cloth we actually create an imbalance between the electrons, and because of this imbalance the electron tries to move, or simply you can say that, we have just applied the energy to our box. These electrons with the imbalance is called to have potential energy.  Why potential? Because, it has a potential to move from one place to another, if we give them a path. 

Why Voltage is referred between 2 points ?

The voltage is always referred between two points and hence it is also called as potential difference between two points. When we are saying that, we are moving our box from one place to another place we’re actually talking about the two places, or simply between the two points in case of electrons, and that is why the voltage is always referred between two points. 

Now the question is, do we always need to rub something, to create this imbalance of voltage?  The answer is no..! You don’t need to rub two things to create the imbalance or voltage. 

How to generate voltage?

We can generate imbalance between electrons/voltage by any of the following ways:

• Generator
• Chemical reaction
• Battery
• Alternator
• Solar energy, etc. 

Voltage is measured in volts! 

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What is Current ?

Now, let’s understand the concept of current. Consider that, you have a water tank, too which you have connected a pump. Now, to make the water to reach its destination you will need to start the pump and provide it a path which means, you have to connect a pipe to it. As soon as you start the pump, water will start moving to its destination through the pipe s you have connected. What if your pipe is broken in between or you have not started the pump, what will happen? Your water will not reach to its destination.

Now from this we can have two important conclusions.

1. We need a force (pump) to make the water move
2. Water needs path to flow, a closed path…!

So, if you have understood the above concept, you have understood the concept of current.

How? Read the next paragraph.

As you have applied the voltage, or let’s say you have started the pump, now, the only thing you need to do is, provide it a path, like we connected a pipe for the water. So, provide a path by connecting a conductor, and bingo, your electrons will start flowing through it.

And this flow of electron in a closed circuit is called as Current.

If your conductor is broken like the pipe, or if you haven’t applied voltage, like you haven’t started your pump, your electrons will not flow either, like water. Remember, if you want electrons to flow continuously you will need a closed path and a continues push for them.

We measure current in Ampere. 

And one more thing you have to remember here is that, electrons will keep on moving continuously, until the voltage keeps pushing them.

This single direction flow of electrons is called as “Direct Current”, and if current is changing its direction then it is called as “Alternating Current”.