Agenerator is a device that uses an electromagnet to turn an axle has fanlike blades that turn when pushed increases or decreases the voltage and current of two ac circuits converts mechanical energy into electrical energy by rotating a coil of wire in a magnetic field

converts mechanical energy into electrical energy by rotating a coil of wire in a magnetic field

Explanation:

generator is based on the principle of Electromagnetic Induction given by Faraday's law.

As per above law rate of change in magnetic flux will induce EMF in closed coil.

here we know

so we will have

so in this way if we rotate a coil between magnetic field of strong magnets by using mechanical energy then it will produce electric energy.