All those things are part of our every day life. Just think, that if there were no electricity you wouldn't be reading this article right now, because your computer would not work. Or if you just got a new TV, you plugged it in the outlet and it wouldn't work because a TV doesn't work on its own, it needs the help of electricity. It's pretty simple. A mechanical energy used for powering magnetic generators is transformed into electrical energy.
Magnetic generator is basically a coil of wire that rotates between two magnets.
Due to magnetic field between these two magnets electrons in the coil are propelled along the wire. As the coil keeps rotating, during one half of a turn, the electricity travels one direction through the coil. During other half, it travels other direction. One complete revolution of the coil is called a cycle. The number of such cycles in a second is called the frequency of the voltage or current.