What is Transformer and its Types

Transformer is a device which increases or decreases AC voltage.

Working Principle of Transformer :

It works on the principal mutual induction between the two coils.

 What is Transformer 

Construction  of  Transformer:

A simple two winding transformer consists of an iron core. This iron core is obtained by the collection of a large number of soft iron strips which are stick together in the form a thick core. Now we wind one coil of wire on left hand of core and wind second coil on the right hand side of core. Now on left hand side we attached an AC source of voltage VP called voltage applied to primary coil. On right hand side of coil we attached a load across which VS voltage is produce.

Types of Transformer :

Transformer has two types: 

•  Step up Transformer
•  Step down Transformer

Step Up Transformer :

 That transformer which increases the AC voltage from low value to a high value is called Step Up Transformer.

So this transformer  gives increased  voltage. 

Step down Transformer :

 That transformer which decreases the AC voltage from high value to low value is called step down Transformer. So this transformer gives decreases voltage.

In this transformer 

 here 

Ns  = Number of turns in the secondary coil. 

Np  = Number of turns in the primary coil. 

VS  = Voltage obtained from secondary coil. 

Vp  = Voltage applied to the primary  coil. 

The following figure show the  diagram of step up and step down transformers.

Auto Transformer:

A special type of transformer which has only one winding from which input and output is generates is called auto transformer.

 Generally a transformer has two winding one for  input other for output. But in auto transformer we have a single winding which is taped in ordered to connect a load as shown.

According to the situation auto transformer  can be used as step up as well as step down. BC winding is called common winding while AB winding is called series winding. If input is applied at left hand side and output is taken at right hand side the number of turns on the right hand side is smaller than it acts as a step down transformer. If input is  applied on right hand side and output is applied on left hand side and number of turn is larger than it acts as a step down transformer. In variable auto transformer the tape is moveable and the number of turns can be changed to change the output voltage.