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Difference Between Voltage and Current

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Current and Voltage Difference

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We know that a battery has a positive and a negative terminal. As soon as the voltage is applied to the circuit, pressure or electric tension generates inside it because of some difference called the potential difference. 

Now, this pressure pushes the charged electron to move from the negative terminal of the battery to the positive. This movement of electrons from a negative terminal to a positive is what we call the current. 

This article discusses the current as of the flow of electrons, and the voltage responsible for pushing the current from one end to the other, and the current voltage difference. 


How to Differentiate the Current from Voltage?

Now, we will discuss the difference of voltage and current:

From the above statement, the voltage was labeled as an electric tension, electric pressure, and the potential difference. 

We know that the voltage is generated at the power station. Electrons move randomly inside the circuit, and to give a direction to the electron flow from a negative terminal of a battery to the positive, some push is required; that push is the voltage.

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To understand what voltage is, we will consider an example of a water tank.

Let’s suppose that an empty water tank is placed below the filled tank. Now, as soon as the tap is opened, the water starts flowing out of the upper tank. However, this happens only when pressure is applied to the water in the upper tank. 

Similarly, on connecting the circuit to the battery, a difference generates across its ends. The difference coming out from an electric circuit’s power source is called the potential difference/voltage.

The voltage/electric pressure pushes the charged electrons to migrate from the negative end of the battery to the positive side and continues to loop inside the circuit/conducting loop, the flow of electrons produces the current inside the circuit.

Now, these charged electrons or the current do the work in the form of lightning a bulb.

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Thus voltage is the electric tension/pressure that forces the electrons (current) to flow through the circuit that generates electricity, and the bulb glows.


Differentiate Between Current and Voltage

The below table lists the difference between voltage and current:

Current vs Voltage


Current 

Voltage

Definition

An electric current is the number of charged electrons flowing in the circuit in a second.


In simple words, the current is the flow of electrons between two points forced by voltage. 

Voltage is the difference in the electric potential energy, per unit of charge between two points. 


In simple words, a voltage is a potential difference between two points in an electric field that forces electrons to move in a particular direction in the circuit, and therefore, generate current.

Formula

The formula for the current is:

I = q/t


Charge flowing per unit time

Voltage = Work/Charge or W/q


This formula states that voltage is the work done to move a positive test charge from one point to the other.

Dimensional formula

The dimensional formula for the current is [M0L0T0A1]

The dimensional formula for the voltage is [M1L2T-3A-1]

Unit

The unit of current is Ampere or ‘A’.

The unit of voltage is Volt or ‘V’

Measuring device

Current is measured by Ammeter.


The ammeter is always connected in series in an electric circuit.

Voltage is measured with the help of a Voltmeter.


The voltmeter is always connected in parallel to the electric circuit.


Now, let’s take another example to understand how voltage and current are related to each other.

Let’s suppose that a water tower is placed standing in a river and it is filled with water. Now, the water tower has enough potential energy to do work. The pump, connected to its right-hand side, and to complete the circuit, a pipe is connected to the left of the tower.

This pump generates pressure on the water tower, which in turn, pushes the water out of the pipe. On increasing the width of the pipe, the potential energy of the tower remains the same, however, the volume of the water flowing out of the pipe increases. Even if we remove the pipe, the potential energy still remains the same. 

So, here pressure is the voltage, and water flowing out of the pipe is the current. 

This is what we have seen in the remote cells, whether connected to the circuit or left idle, the voltage of the cell remains the same.


Point to Remember

V ∝ I

The current flowing through the circuit is directly proportional to the push offered by the circuit to the flow of electrons in a particular direction.

It means the more is the pressure, the more is the water flow or the current flow in the circuit, and vice-versa.

If the potential difference between the two points of the pipe through which water flows is increased, the voltage also increases. It's because the voltage is the potential difference between two points.

FAQ (Frequently Asked Questions)

1. Can the voltage exist without current?

Yes! Voltage can exist without current, while the current cannot flow without voltage. It’s like you want to drive your new car. To drive it (for current flow), you need to start the engine, and without starting it, you cannot move the car even a single-step ahead; this is how voltage pushes the car (current) to move ahead (flow).

2. What is the difference between current and voltage with a real-life example?

Let’s suppose that you didn’t qualify for an entrance exam and are not willing to study for the upcoming exam. All you need is a push to study for the exam. The moment you get it, you start your preparation with full energy. So, the push is the voltage, and preparing with the flow for the exam is the current.

3. Can we control the voltage in a circuit?

Yes!

As per the formula V = IR, we can control the voltage by varying the resistance in the circuit or the conducting loop.

4. How many volts are there in an ampere? What is the safe voltage for a human body?

12 volts are there in 1 ampere. 30 V is the safe voltage for the human body.