A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. Electromagnetic induction produces an electromotive force across a conductor which is exposed to time varying magnetic fields. Commonly, transformers are used to increase or decrease the voltages of alternating current in electric power applications.
A transformer makes use of Faraday's law and the ferromagnetic properties of an iron core to efficiently raise or lower AC voltages. It of course cannot increase power so that if the voltage is raised, the current is proportionally lowered and vice versa.
Principle of Transformers
A transformer is a device that changes (transforms) and alternating potential difference (voltage) from one value to another value be it smaller or greater using the principle of electromagnetic induction.
A transformer consists of a soft iron coil with two coils wound around it which are not connected to one another. These coils can be wound either on separate limbs of the iron core or be arranged on top of each other.
Voltage in secondary Coil / Voltage in primary Coil = Turns on Secondary Coil /Turns on primary Coil
Vs /Vp = Ns/Np