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A transformer Iis a device that transfers electric energy from one alternating-current circuit to one or more other circuits, either increasing (stepping up) or reducing (stepping down) the voltage. Transformers come in two varieties – step up, which increases the voltage or current, and steps down, which decreases the voltage or current input. For example, the transformer in your microwave Oven is a secondary transformer that is used to supply around 2200Volts to the vacuum tube in the Microwave Oven.


Transformers are used for different purposes varying purposes

1.      They are used to reduce the voltage of conventional power circuits to operate low-voltage devices, such as doorbells and toy electric trains.

2.      They are used to raise the voltage from electric generators so that electric power can be transmitted over long distances.

How do transformers work

To understand the working of a transformer, we need to go back in time, to Michael Faraday’s laboratory.

Michael Faraday can perhaps be called the father of the transformer since it was his experiments that helped us understand electromagnetism and develop devices like motors and generators.

In the late 1800s, when it was discovered that electricity and magnetism were related phenomena, there was a race to try and build a practical device that could harness the power of magnets to generate electricity.

Faraday found out that electricity could be generated by bringing a magnet close to a coil of wire. What he discovered was that voltage will be produced only when the magnetic field was changing, that is, if he moved either the coil or the magnet relative to the other.

In DC, the current flow is steady and so is the magnetic field. Since the field is steady and not changing, there is no voltage induced on the secondary and the transformer just looks like a normal coil of resistive wire to the power supply. So, transformers do not work with DC currents.

He also found that when two coils of wire were kept close to each other, a current flowing in one coil could induce a current in the other coil. This principle is called mutual inductance and governs the working of all modern transformers.

Transformer Parts and Construction

The three main parts of a transformer:


1.      Primary Winding of Transformer

2.      Magnetic Core of Transformer

3.      Secondary Winding of Transformer

-        Primary Winding of Transformer

Which produces magnetic flux when it is connected to an electrical source.


-        Magnetic Core of Transformer

The magnetic flux produced by the primary winding, that will pass through this low reluctance path linked with secondary winding and create a closed magnetic circuit.


-        Secondary Winding of Transformer

The flux, produced by the primary winding, passes through the core, will link with the secondary winding. This winding also wounds on the same core and gives the desired output of the transformer.

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