In an earlier tutorial, we have studied all the basic concepts of voltage, potential difference, and electromotive force.
Now, study here- Is electric potential and EMF are same terms?
Table of Contents
Difference between EMF and Potential Difference
Let’s compare the different specifications of electromotive force and potential difference in tabular form.
| # | Content | Electromotive Force | Potential Difference |
| 01 | [Definition] What is the electromotive force & potential difference? | Electromotive force is nothing but force. It is another form of energy. The energy is necessary to move the free electron and to produce an electric current through a particular direction in a closed circuit. This energy called ‘Electromotive Force’. | The energy is necessary to move the free electron and to produce an electric current from one place to another in between two terminals of the electrical circuit. This energy is called as a ‘Potential Difference’ |
| 02 | Representation | Electromotive force is denoted by the ‘E’ or ‘ε’ cursive letter of E). | Potential difference is denoted by the ‘V’. |
| 03 | Known as | Sometimes, an electromotive force is known as ‘Electrical potential’ or ‘EMF’. | The potential difference is known as ‘Voltage’ or ‘PD’. |
| 04 | Current function | Due to the EMF, the electric current is transmitted throughout the circuit. | Due to the potential difference, the electric current is transmitted between two points or load-connected terminals. |
| 05 | Relation between EMF & PD | EMF is always higher than the total voltage or potential difference (i.e. EMF>V). | The total voltage or potential difference is always lower than the EMF (i.e. V<EMF). |
| 06 | Circuit operation | In an open circuit, you can measure the EMF. | In a close circuit, you can measure the voltage or PD. |
| 07 | Function of EMF & MMF | The main function of EMF is to maintain the potential difference. | The main function of potential difference or voltage is to flow electron or electric current. |
| 08 | External Resistance Role | The electromotive does not depend on the external resistance (R) in an electrical circuit. But, it depends on the internal resistance (r) of the battery. | The potential difference depends on the external resistance (R) in an electrical circuit. |
| 09 | Measurement of EMF & PD (You can see in following circuit diagrams) | You can measure the value of emf only at the two endpoints of the connected source (for example, battery) of an electric circuit. | You can measure the value of potential difference at any two points between connected load (for example, resistance) of an electric circuit. |
| 10 | Measuring Instrument | Electromotive force is measured by the ‘EMF meter’. | The potential difference is measured by the ‘Voltmeter’ or ‘Multimeter’. |
11. Circuit Diagram of Electrical Circuit
- Electromotive force representation in an electric circuit:
The electromotive force (EMF) provides the energy that can continuously flow free electrons and produce electricity through a conductor in a specific direction.
- Potential difference representation in an electric circuit:
In an electrical circuit, when the electric current passes through the resistive load, the voltage changes between two terminals (i.e. ‘A’ and ‘B’).
In between two given ‘A’ and ‘B’ terminals, the occurring voltage is called a ‘Potential Difference’. And sometimes this changing voltage is called as a ‘Voltage Drop’.
Note: In the above diagram, point ‘A’ represents the higher potential (+ve terminal), and point ‘B’ represents the lower potential (-ve terminal).
12. Calculation of EMF & Potential Difference
– by using Voltage, potential difference and electromotive force online calculator.
- Electromotive force calculation:
The formula of electromotive force or EMF is-
Electromotive force, (E) = [I * (R + r)] (Unit- Volt)
Where,
I – Electric current is passing through the circuit.
R – External resistance
r – Internal resistance
- Potential difference or voltage calculation:
The formula of potential difference or PD is-
Potential difference or voltage, (V) = ( I * R) (Unit- Volt)
These 12 points have covered the difference between emf and potential difference with help of the circuit diagrams.
Similarities between EMF and Potential Difference
The SI unit ‘Volt or V’ is the similarities of electromotive force and the potential difference.
If you have any queries regarding the distinguish between emf and potential difference, ask in given comment.
Read some related Differences:
- Alternating Current vs Direct Current
- Electromotive Force vs Magnetomotive Force
- Resistance vs Reactance
- Capacitor vs Battery
- Open Circuit vs Closed Circuit
- Electric Motor vs Generator
- Analog Multimeter vs Digital Multimeter
Thanks for Reading!
I have completed master in Electrical Power System. I work and write technical tutorials on the PLC, MATLAB programming, and Electrical on DipsLab.com portal.
Sharing my knowledge on this blog makes me happy. And sometimes I delve in Python programming.