Transformer

Transformer:-

it is an electrical device which step up or step down AC voltage with no change in frequency.
In its construction it contain a core made of ferromagnetic sheets which may be in F, E and I shaped.
Insulated copper wire is used as its winding.
Core has two sides primary and secondary side.
If it is step down transformer its primary side has greater number of turns of winding then Secondary.
and if it step up transformer, number of turns on primary side is less then secondary.
In both side of transformer total power remains constant that is IV (current*voltage).

We have a formula to calculate number of turns 
                            Vp/Vs  =Np/Ns
Vp is primary voltage
Vs is secondary voltage
Ns is number of secondary turns
Np is number of primary turns

Example of Step up transformer:-   Inverter which step up voltage    form 12 V to 220V Ac which is used in UPS(uninterrupted power supply)

Example of Step down transformer:-  5V DC power supply, in this power supply we have to convert 220V ac to 5V ac by step down transformer then by using bridge rectifier we can convert it in to dc