Electromotive force (f.e.m.) is the electrical potential, measured in Volts, supplied by a generator, such as a battery, to an electrical circuit or device. It is a scalar quantity that can be defined as the electrical potential energy per unit of charge.
Lookalso: Electric generator and electromotive power
What is electromotive force?
Electromotive force can be understood as the amount of work that a generator performs to move electrical charges between two points in a circuit. Batteries are capable of performing work on electrically charged particles, transforming many differentshapes energy into electrical energy.
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real generators
You electric generators are the sources of strengthelectromotive, that moves electronic devices. Like all real devices, generators feature electrical resistance internal nonull, that is, when you connect an electrical generator to some circuit or electrical device, onepart of the electromotive force it produces is
dissipated by its own functioning, due to the Joule Effect. In this way, the generator ends up providing a electric potential a little less than its electromotive force.
US electric generators, the sense conventional of current shows that electrical charges always flow from the lowest (-) to the highest (+) electrical potential, indicating that, during their passage through the generator, the charges gain electrical energy. In devices that consume this electrical energy (resistors and receivers), the current direction always goes from higher for the lowest potential, since these devices use part of the energy present in the current electric.
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Subtitle AND – Electromotive force – Volt [V] ri – Internal generator resistance – Omh [Ω] i – Electric current – Ampere [A] + Positive pole of the generator - greater electrical potential - Generator negative pole - lower electrical potential |
Lookalso: real sense and conventional sense.
electrical potential that generators can, in fact, deliver to circuits is called potentialuseful (Uu) or usable. The maximum potential they produce is called electromotive force (E), while the potential consumed by them due to their internal resistance is the potentialdissipated (ri.i):
The figure below shows a circuit real, formed by Associationintwogeneratorsreal (stacks), which have a certain value of resistanceinternal, connected to two lamps. In this circuit, the lamps are the devices that make use of the useful potential provided by the batteries:
Check out some exercises on the topic:Exercises on generators and electromotive force.
By Rafael Hellerbrock
Graduated in Physics
Would you like to reference this text in a school or academic work? Look:
HELERBROCK, Rafael. "What is electromotive force?"; Brazil School. Available in: https://brasilescola.uol.com.br/o-que-e/fisica/o-que-e-forca-eletromotriz.htm. Accessed on June 27, 2021.
