Electromotive Force (EMF，电动势)
In short, EMF is:
1
changing magnetic field -> induced voltage
It’s characterized by the Faraday’s law:
\[\begin{gather*} \begin{aligned} & \epsilon = -N \frac{\Delta \phi}{\Delta t} \end{aligned} \end{gather*}\]- $\epsilon$ is the electromotive force (EMF), or commonly, “induced voltage”
- $Delta \phi$ is the change in magnetic flux.
- $N$ is the number of coils
Basically, Faraday’s law is to say “the induced voltage is the negative of the total rate of change of flux linkage”
EMF’s unit is volts but it’s also joules/column
Eddy Current
Eddy current is called “eddy” because it looks an eddy or whilrpool in fluid dynamics. Under the hood, it’s Faraday’s Law.
