# What is electric generators?

Jun 8, 2015

Electric generators are mechanical machines which transfer mechanical energy given to it to electrical energy.

It consists of a magnetic field (generated by electromagnets) which are generally rotated by mechanical force around an axis.
Due to electromagnetic induction, electric potential is generated which is then extracted from it with means of two wires, which carries the current (also takes it back as well).

If $\omega$ be the angular frequency of rotation, then the emf generated is,

E = E""_0 Sin omegat where E""_0 is the peak value of voltage when $S \in \omega t = 1$.

As one might notice, the value of $E$ shall take values between E""_0 and -E""_0 and shall periodically repeat the values as $\omega$ changes.

This is called an alternating emf. The current so generated also alters it's direction periodically, and is called to alternating current.

It may be transformed into direct (unidirectional) current by means of a full-wave rectifier.