In electrical and magnetic circuits, electromotive force (EMF) and magnetomotive force (MMF) are playing vital roles respectively.
But, these two forces have different specifications which are used for different fields or circuits.
Let’s study what is the difference between electromotive force (EMF) and magnetomotive force (MMF).
Difference between EMF and MMF [in Tabular Form]
| # | Content | EMF | MMF |
| 1 | What is meant by EMF & MMF? | EMF stands for ‘electromotive force’. | MMF stands for the ‘magnetomotive force’. |
| 2 | [Definition] What are emf & mmf? | The force is necessary to move the free electron and to produce an electric current in a particular direction. This force called ‘Electromotive Force’. | The force is necessary to generate the number of magnetic field lines or magnetic fluxes passing through a surface. This force called is the ‘Magnetomotive Force’. |
| 3 | EMF & MMF are known as | Sometimes, an electromotive force is known as ‘electrical potential’ or ‘EMF’. | Magnetomotive force is also known as ‘magnetic potential’ or ‘MMF’. |
| 4 | Representation | EMF is denoted by the ‘E’. | MMF is denoted by the ‘Fm’. |
| 5 | SI Unit of EMF & MMF | This force is measured in ‘Volt’ (V). | This force is measured in ‘Ampere-Turn’ (AT). |
| 6 | Working role | Due to the EMF, electric current flows from Positive polarity (+ve) to Negative (-ve) polarity. | Due to MMF, magnetic flux flows from the North (N) pole to the South (S) pole. |
| 7 | Function of EMF & MMF | The main function of EMF is to establish and move electric current through any particular direction (i.e. ‘+ve’ to ‘-ve’) in the closed electric circuit. | The main function of MMF is to establish and move magnetic lines or fluxes through any particular direction (i.e. ‘N’ to ‘S’)in the closed electric circuit. |
8. How to calculate the EMF and MMF?
According to the Ohm’s law of an electric circuit, EMF is calculated by using the formula,
Electromotive force, (EMF) = (Electric current * Resistance) = (I * R) (Unit-Volt)
You can calculate the EMF by using online calculator.
[CP_CALCULATED_FIELDS id=”8″]
Total electromotive force, Ʃ(EMF) = (IR1+IR2+IR3+…+IRn) (Unit-Volt)
And the general formula of electromotive force or EMF is-
Electromotive force, (E) = [I * (R + r)] (Unit- Volt)
[CP_CALCULATED_FIELDS id=”69″]
According to the Ohm’s law of magnetic circuit, EMF is calculated by using the formula,
Magnotomotive force, (MMF) = (Magnetic flux * Reluctance) = (ɸ * S) (Unit-Ampere-Turn)
Calculate the value of MMF by using online calculator.
[CP_CALCULATED_FIELDS id=”31″]
Total magnotomotive force, , Ʃ(MMF) = (ɸS1+ɸS2+ɸS3+…+ɸSn) (Unit-Ampere-Turn)
9. Circuit Diagram of Electrical and Magnetic Fields
When current flows through the conductor, electromotive force (EMF) is produced to move the electron. Thus, emf is responsible for to flow of current in a closed electric circuit.
You will see a given electric circuit diagram.
Similarly, in the magnetic circuit, magnetic lines or fluxes are generated due to the existence of magnetomotive force (MMF).
These 9 points are covered the major difference between EMF and MMF with the help of the circuit diagram.
If you have any queries regarding emf vs mmf, you can ask in the comment section.
Read some related differences:
- Resistance vs Reluctance
- Resistance vs Impedance
- Alternating current vs Direct current
- Open circuit vs Closed circuit
- Series circuit and Parallel circuit
- Core transformer vs Shell transformer
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.