## Working of a simple transformer.

### What is a Transformer?

A transformer is a stationary electrical device or machine. A transformer can not convert electrical energy into another energy, it only transforms electrical energy from one circuit to another circuit at one voltage level to another voltage level. That's why it's named Transformer. Obviously Transformer work in AC cannot work in DC. The transformer does not change frequency and power. The transformer has no rotating part that's why it is called a stationary device or machine.

### Construction of a Simple Transformer:

The transformer has two stationary electric circuits or winding or coils that are coupled magnetically. There is no electrical contact between them. The primary and secondary coil wound on a ferromagnetic material which is called Core. The core transfer the changing magnetic flux from the primary winding or coil to the secondary winding or coil. Each winding or coils of the Transformer has no of turns as per requirement voltage level.

### Working Principle of Transformer:

The transformer works in the principle of mutual induction. The AC supply fed to one of the two coils which are called the primary winding and the other winding which is connected to the load is called secondary winding. So when the alternating current flows in the primary coils, a changing magnetic flux is generated which is linked with both the primary and secondary coil by the core. According to Faraday's laws of electromagnetic induction, an EMF is induced in the secondary winding. This induced EMF drives a current if a load is connected to the secondary winding. The magnitude of the output voltage can be controlled by the ratio of the no. of the primary coil and the secondary coil. Self-Inductance also has seen in the primary winding in a Transformer which limits the flow of current in the primary winding.

### Why Transformer cannot work in DC?

If DC supply given to the transformer the produced flux remains constant it not changing so EMF will be not induced. As self-inductance does not appear in the primary winding a huge amount of current will flow through the primary coil(As the coils of the transformer have low resistance), so the winding gets damage. For this reason, the transformer cannot work in DC.

### Classification of Transformer:

1. Shell Type
2. Core Type
3. Berry Type

#### Based on Output Voltage:

1. Step-up Transformer
2. Step-down Transformer

#### Based on Application:

1. Power Transformer
2. Distribution Transformer

#### Based on the number of Phases:

1. Single Phase Transformer
2. Three Phase Transformer