What is Potential Difference? Definition, Formula

potential difference

What is the Potential Difference?

The potential difference is the difference in electrical potential or voltage between two different points in an electrical circuit and it is defined as the work done needed per unit to move the electrical charge from one point to another point. We know that the potential difference in an electrical circuit is also known as Voltage or electric pressure. This voltage or potential difference causes to flow of the electric current through an electrical circuit. We know that the current flows in a circuit in the opposite direction to the flow of electrons.

How Potential Difference Occurs?

When the potential difference is generated across any conductor electrons or electric current start flowing through that conductor. There are different types of principles, devices, and machines that are used to produce voltage or potential differences. The electrical potential difference between two points can occur by different causes such as discharging of electric charge from a capacitor. Other important causes are the piezoelectric effect and thermoelectric effect.

The potential difference can be generated manually such as by producing electromotive force in a generator, making electrochemical processes such as cells, batteries, etc.

Electrical Potential Difference or Voltage Unit and Formulas

The SI unit of electrical potential or voltage is Volt.

There are so many formulas and equations available to find out the potential difference.

For, example when we have the value of current flow in a circuit and the value of total resistance, the potential difference or voltage can find out by,


Here, the voltage is V, the Current is I, and the Resistance is R

The potential difference is symbolized by 'V'

Measurement of Electrical Potential

Electrical potential is measured by a voltmeter. To measure the voltage in a circuit we have to connect a voltmeter in parallel with the circuit.

When we measure voltage in a DC circuit, we have to connect the voltmeter with proper polarity, otherwise, it will show a negative or wrong rating.

When we measure voltage in an AC circuit, there is no polarity. In a three-phase AC system, we have to connect the voltmeter across a phase terminal and a neutral terminal to measure the phase voltage, and we have to connect the voltmeter across two phases to measure the phase voltage. Of course, the phase voltage is lower than the line voltage.

Important Factors of Potential Difference

When there is two or more source of voltage in the same circuit then we need some calculation and knowledge to know the actual potential difference of the whole circuit. For example, when there are four points A, B, C, and D in a circuit. So the potential difference between A and D will be the total potential difference between A, B, and C, D.

When adding voltages during calculation the polarity and magnitude of the individual sources also be noted. Kirchoff's current law and voltage law are very helpful in finding out the potential differences.

Also, the knowledge of potential drops or voltage drops is very important. Generally, the voltage drop happens across the component that resists or blocks the flow of current. For, example when a resistor is connected in series between a power source and load. The voltage drop will happen across that series resistor. And it happens due to the opposition of current flow by the resistor. The voltage drop by the resistor will be the multiplication of the value of that resistance and the value of the current flowing through that resistor.

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What is Potential Difference? Definition, Formula What is Potential Difference? Definition, Formula Reviewed by Author on April 24, 2022 Rating: 5
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