I had once stayed six months in a blackout because the transformer supplying our region got bad. If you are in Nigeria, it is common talk to hear about transformers (especially when it's faulty), you may likely see it along the road as you walk or drive by. What is a transformer? Why is that piece of electric equipment important?
Let us start with the former question.
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![1512903162957.png](https://steemitimages.com/DQmWCENUBtqoWbRhd1BYRR5GGDvAk3gdcxvCL7vZPLmpUtm/1512903162957.png)
<sup>[Source](https://pixabay.com/en/high-voltage-feed-windstrom-1290375/): A Power Transformer in an Electric Power Station</sup>
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<br>
#### What is an electric transformer?
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An electric transformer is a static (no moving parts) electrical device that transfers electrical energy between two or more circuits through the process of **electromagnetic induction.**

Electromagnetic induction is simply the production of electromotive force (emf) or voltage due to a change in the magnetic field.

The transformer basically works through the principle of electromagnetic induction.
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#### Basic Components of a Transformer
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There are three basic components of a transformer:

1. The coils (primary and secondary windings made up of insulated aluminum or copper wire),
2. The core; and
3. The enclosure.
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![1280px-Transformer3d_col3.svg.png](https://steemitimages.com/DQmaTu1SvQNZSDvZszWEBtd8XzunHxts3w5vknF1RbRcAcn/1280px-Transformer3d_col3.svg.png)
<sup>[Source, Wikipedia](https://en.wikipedia.org/wiki/Transformer): An ideal transformer</sup>
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**The Primary Winding:** This receives energy from the power source.

**Secondary Winding:** This delivers energy received from primary windings to the output (load).

**The Core:** That is the magnetic circuit which provides a path for the flow of magnetic field (magnetic lines of flux) around it.


**The Enclosure:** This is the protective part of the transformer that shields the above-listed components from mechanical damage, moisture, and dirt.
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#### Principle of Operation
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An alternating current applied to the primary coil, a magnetic field (an invisible magnetism pattern) is generated. This magnetic field is sometimes referred to as magnetic flux. The strength of this generated magnetic flux is dependent on the size of current applied to the primary coil. Through the principle of electromagnetic induction, a fluctuating, magnetic field around a piece of wire **induces** current on the wire. This current is referred to as **primary current**, denoted by **I<sub>p</sub>**. If a second coil (secondary winding) is placed next to the primary coil, an electric current is *induced* in the secondary coil. This current is known as the **secondary current** and is denoted by **I<sub>s</sub>**.

It is important to note that the **primary** and **secondary** coils of a transformer are not **physically connected**, current only moves from one winding to the other via electromagnetic induction.

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There is another important aspect of a transformer that determines the type and/or function of the transformer. It is dependent on the transformer turns ratio (TTR).

This is the ratio of the number of turns of wire in the primary winding denoted by **N<sub>p</sub>**, to the ratio of the number of turns of wire in the secondary winding denoted by **N<sub>s</sub>**.

To calculate the TTR, you would use the following equation:

V<sub>p</sub>/V<sub>s</sub> = N<sub>p</sub>/N<sub>s</sub>= I<sub>s</sub>/I<sub>p</sub>

**V<sub>p</sub>** = Voltage on the primary winding
**V<sub>s</sub>** = Voltage on the secondary winding
**N<sub>p</sub>** = Number of turns of wire in the primary winding
**N<sub>s</sub>** = Number of turns of wire in the secondary winding
**I<sub>s</sub>** = Current on the secondary winding
**I<sub>p</sub>** = Current on the primary winding
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#### Step Down Transformer
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<div class="pull-right"><center><img src="
![step-down-transformer.gif](https://steemitimages.com/DQmSAbvWYhnf3trNgqSirq63hFXJvruydxbngy8knaYpQzc/step-down-transformer.gif)" /><br/><em><a href="https://b2bbusinessnews.files.wordpress.com/2012/10/step-down-transformer.gif">Source</a></em></center></div>
A step down transformer is the type of transformer where the number of turns of wire on the secondary winding is smaller than the number of turns in the primary.

N<sub>s</sub> `<` N<sub>p</sub>

In step down transformer, the secondary voltage is **always smaller** than the primary voltage.

But as you could see the power in this example (2000w) never changes. Transformer only changes current and voltage but never frequency and power (though there may be some power loss due to **eddy current** or I<sup>2</sup>R losses).

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#### Step Up Transformer

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<div class="pull-right"><center><img src="
![Transformator-Step-Up.gif](https://steemitimages.com/DQmP6JUbnbyMsGwPdHv74sYHK7nQ9FxriEiJ5nqjcuQeuM9/Transformator-Step-Up.gif)" /><br/><em><a href="http://www.rangkaianelektronika.org/wp-content/uploads/2014/12/Transformator-Step-Up.gif">Source</a></em></center></div>

In step up the *primary winding is smaller* than the secondary winding.

N<sub>p</sub> `<` N<sub>s</sub>

The input primary voltage **V<sub>p</sub>** is always smaller than the secondary voltage **V<sub>s</sub>**

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#### Isolation Transformer
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<div class="pull-right"><center><img src="
![800px-Trenntransformator.jpg](https://steemitimages.com/DQmcSpzqPNGkoiv4ewoVzmx4DUXn4RbQVuoaym6mH9D64vk/800px-Trenntransformator.jpg)" /><br/><em><a href="https://en.wikipedia.org/wiki/Isolation_transformer">Source:Wikipedia</a></em></center></div>

It is important to mention another type of transformer known as **isolation transformer**. The ratio of the primary to secondary windings respectively is 1:1. Theis means that both the number of turns in the primary winding N<sub>p</sub> is same as the number of turns of the secondary windings N<sub>s</sub>.
<center>N<sub>p</sub> = N<sub>s</sub></center>
The voltages too are the same. The transformers are used majorly for protection of secondary circuits and guard against electric shock for individuals plus interference block.

<center>V<sub>p</sub> = V<sub>s</sub></center>
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<br>
#### Uses of Transformers
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The transformer has got a very wide application in both electrical and electronics systems. The functions of a transformer include:

1. **Electric Transmission:** Electric power is generated in very distant location and needs to be sent to locations hundreds of km or miles away. Using a step up transformer, these voltages are stepped very high. In Nigeria, the transmission voltage is 330,000 volts (for the national grid). 
But the generator terminal voltage of generating station is usually a fraction of that. For instance, [Afam Power generating station in River State Nigeria](http://www.nercng.org/index.php/licencees/140-afam-power-plc), terminal generated voltage is 11,500Volts or 11.5KV. 
<div class="pull-right"><center><img src="
![cf825cde71122fcbfe59be82d4732ba1--electrical-engineering-transformers.jpg](https://steemitimages.com/DQmP6q3X6FgEGaZ9TRbNZK22gBgMxXJsEesALkcig3sNoZf/cf825cde71122fcbfe59be82d4732ba1--electrical-engineering-transformers.jpg)" /><br/><em><a href="https://i.pinimg.com/736x/cf/82/5c/cf825cde71122fcbfe59be82d4732ba1--electrical-engineering-transformers.jpg">Source:Pinterest, A Step Up Power Transformer</a></em></center></div>
A step up transformer now steps it to 330KV for transmission to neighbouring states. The reason is high volatge requires a smaller size of cable (cutting cost of making large gauge wires) since the current would be small. This also reduces losses over the great distances the electricity would have to transverse before getting to the consumers.


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**2.** **Electric Distribution**: A step down transformer is needed for distribution of the high voltage coming in from the transmission station. <div class="pull-right"><center><img src="
![electricity-2820425_1280.jpg](https://steemitimages.com/DQmSG7aHN1MmBcP2bY7NeTedUrHY2GKLccnib5xr8mDeRmn/electricity-2820425_1280.jpg)" /><br/><em><a href="https://pixabay.com/en/electricity-transformer-power-2820425/">Source:Pixabay, A Step down Power Transformer used for distribution</a></em></center></div>

These are the types you commonly see hanging from electric utility poles and besides street corners.


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**3.** **Protection**: Isolation transformers protects us from dangerous voltages and isolates circuits from damage. 
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**4.** **Measurements:** We have different types of electrical measures. Examples include current, voltage, power, etc. So there are special transformers such as current transformers, potential transformers, etc.
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**5** **Filter:** A transformer could serve as a block or filter that prevents the direct current (DC) from passing a particular point since only alternating current (AC) could pass through the transformers.
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These are some of the uses as this is not an exhaustive list just something for us to use to gain some insights on the transformer. Thank you for reading.

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Ref: [1](http://www.ecmweb.com/content/basics-transformers-part-1), [2](https://en.wikipedia.org/wiki/Transformer),[3](http://www.explainthatstuff.com/transformers.html),[4](https://www.elprocus.com/various-types-of-transformers-applications/).