Understanding a transformer is not a rocket science, as it is simply a static device, whose main function is to supply power from one source to another. Its working is mainly based on Faraday's Law of electromagnetic induction. It has coils, windings and cores perform its working of power transmitting without making any changes in the frequency. Its primary coil is basically connected to the alternating current supply, so, current smoothly makes its way to pass through. And its secondary coil is connected to the alternative flux.