What is a Transformer, Symbol, Types, and Turns Ratio

After going through this article, you will be able to learn:

• What is a transformer
• How transformer operates
• The difference between a step-up transformer and a step-down transformer
• Turns ratio of the transformer
• Different types of transformer
• Applications of transformer

What is a Transformer?

Transformers are devices that allow the transfer of the AC signal from one circuit to another. Transformers are generally used for stepping up the voltage, stepping down the voltage, or passing the voltage from one circuit to another without the voltage being unchanged.

If we place two electrically isolated coils next to each other and we pass an AC voltage through one coil then there is a change in the magnetic field. That change in the magnetic field induces a magnetic field and this action refers to Electromagnetic Induction and the device called the Transformer.

In the Transformer, the coil which is having the AC voltage is referred to as the primary winding, and the coil in which the voltage is induced due to the magnetic field is called secondary winding. Now you might be thinking that how much voltage will be induced in the second coil. The amount of voltage induced depends on the mutual induction between primary and secondary coil.

Symbol of a Transformer

Coefficient of Coupling

The amount of the mutual induction is defined by the coefficient of coupling and it is a number ranging from 0 to 1. where ‘1’ indicates all the primary flux line cutting the secondary winding and ‘0’ indicates none of the primary flux cuts the winding.

Rating of Transformer

Transformers are rated in the Volt-Ampere (VA) or in KVA.

Turns Ratio of a Transformer

Turns ratio of a transformer is the number of turns in the secondary winding divided by the number of turns in the primary winding. The turn ratio of the transformer determines whether that Transformer is used for step-down, step-up, or voltage unchanged. Mathematically, it can be written as

Turns Ratio ‘N’= N_s/N_p

Where: P is primary, S is secondary and N is the number of turns

A transformer which is having secondary voltage less than the primary voltage is called a step-down transformer and a transformer with his having a secondary voltage greater than the primary voltage is called a step-up transformer. The amount of voltage that has been stepped up or down depends on the turns ratio. The turns ratio for Step Up Transformer always be greater than 1 and the turns ratio for step down Transformer always be less than 1.

Applications of Transformer

There are many applications of Transformers which are given below:

• Stepping up voltage
• Stepping down voltage
• Phase shifting
• Isolation
• Blocking DC while passing the AC
• Impedance matching

Phase Shift

Now the question arises of how you will get to know whether the transformer will produce a phase shift or not. It is determined by how winding is there in the transformer. When both the primary and secondary windings are found in the same direction then there is no phase shift. If the secondary quality is wound the opposite to the primary winding then the output will be shifted 180 degrees and it represents a phase shift.

Frequently Asked Questions

I hope you understand what is a transformer and if you have a query kindly comment down below.