TRANSFORMER

DEFINITION:

                Transformer is a device which is used to transfer electric energy from one AC circuit to another AC circuit with increase or decrease in current and voltage but without change in frequency.

           In Transformer both input and output are AC quantities

           The transformer action does not take place with DC current, due to constant current there will be no change in the flux linkage in the secondary winding so induced emf will be zero.

              In this blog we will discuss basic information about Transformer.

In the last blog we studied how to make a simple 5V DC power supply, where we used a Step-Down Transformer to convert 230 V AC to required AC voltage. Now the question comes what are Transformers……

PRINCIPLE OF OPERATION:

-As soon as the primary winding is connected to the single-phase AC supply, an AC current starts flowing through it.

-The primary AC current produces an alternating flux in the core of the transformer.

-This changing flux get linked with the secondary winding.

-This varying flux will induce voltage into secondary winding according to the Faraday’s law of Electro-magnetic Induction.

TYPES OF TRANSFORMERS:

   1.     Step-Up Transformer- In Step-Up Transformer we get higher secondary voltage as compared to primary.

   2.     Step-Down Transformer- In Step-Down Transformer we get lower secondary voltage as compared to primary.

   3.     One-to-One Transformer- In this type of Transformer both primary and secondary windings are same hence also called as Isolation Transformer.

TRANSFORMER EQUATION=

For a transformer let….

Φ = Flux linkage

N₁ = No. of turns of primary winding

N₂ = No. of turns of secondary winding

E₁= RMS induced voltage in primary winding

E₂= RMS induced voltage in secondary winding

f= Frequency

E₁= Primary induced voltage= 4.44 N₁ Φ

E₂= Secondary induced voltage= 4.44f fN₂ Φ

TRANSFORMER RATIO:

             The transformer ratio for voltage is defined as the ratio of secondary voltage to the primary voltage. It is denoted by K.

            

             V₂             E₂              N₂

K=     --------- = ---------- = -----------

              V₁            E₁              N₁

TURNS RATIO:

              Turns ratio is defined as ratio of no. of primary turns to the no. of secondary turns.

                             

                           N₁

Turns ratio= -----------

                           N₂

_{APPLICATIONS:}

_{1.         Transfer of electric energy.}

_{2.         Used in many electronics circuits.}

_{3.         Auto-transformer is used as variac.}

_{4.         As a dimmer-stat.}