What Is a Transformer?
A transformer is a static electrical device that transfers energy between two or more circuits.
A current in one coil of the transformer produces a changing magnetic flux, which, in turn, induces a voltage across a second coil wound around the same core.
Electrical energy can be transferred between the two coils, without an electrical connection between them. Faraday's law of induction, discovered in 1831, described the operating principle of transformer action.
Transformers are used to increase or decrease the alternating voltages in electric power applications.
How Does a Transformer Work?
A transformer basically consists of two coils of wire wound around a common iron core. The coil that receives the power is called the primary coil, while the other is called the secondary coil.
The primary coil is connected to an AC source, and the secondary coil is connected to a load (such as a lamp). The current in the primary coil creates a changing magnetic field, which in turn induces a voltage across the secondary coil.
This process is known as electromagnetic induction. The primary coil is said to be the energizing winding, while the secondary coil is the induced winding.
The ratio of the number of turns in the secondary coil to the number of turns in the primary coil is called the transformation ratio. It determines the magnitude of the secondary voltage with respect to the primary voltage.
If the secondary voltage is greater than the primary voltage, the transformer is called a step-up transformer.
If the secondary voltage is less than the primary voltage, it is called a step-down transformer.
The Three Main Parts of a Transformer
There are three main parts to a transformer-the core, the winding, and the enclosure.
Core
The core is made of high-grade silicon steel or ferrite that provides a low magnetic path for the flux.
Winding
The primary and secondary windings are made of copper or aluminum conductors insulated with varnish, enamel, paper, or fiber.
Enclosure
Transformers can be either dry-type or liquid-filled. The enclosure protects the transformer from moisture, dust, insects, and other external factors.
Different Types of Transformers
There are several types of transformers, which are classified according to their application, function, and construction.
The most common types of transformers are:
Step-up Transformer
It increases the voltage from the primary winding to the secondary winding. The number of turns in the secondary winding is greater than the number of turns in the primary winding.
Step-Down Transformer
It decreases the voltage from the primary winding to the secondary winding. The number of turns in the secondary winding is less than the number of turns in the primary winding.
Isolation Transformer
It is used to electrically isolate two circuits. It has a primary winding and a secondary winding that are physically separated.
Auto Transformer
It has only one winding. The primary and secondary windings are physically connected, and the transformation ratio is determined by the turn ratio.
Polarity Transformer
It is used to reverse the polarity of a voltage. It also has a primary winding and a secondary winding that are physically separated.
What Is the Purpose of a Transformer?
Through inductive coupling, transformers transfer electrical energy between two or more circuits.
It serves two main purposes:
- To change the voltage level
- To isolate two circuits
Transformers are used in various applications, such as power generation, transmission, and distribution; audio and video equipment; and electrical appliances.
In power generation, transformers are used to step up the voltage from the generator to the high-voltage transmission line.
In power transmission, transformers are used to step down the voltage from the high-voltage transmission line to the lower-voltage distribution line.
In power distribution, transformers are used to step down the voltage from the distribution line to the level that can be used by household appliances.
Audio and video equipment use transformers to match the impedance of the equipment to the impedance of the signal source.
Transformers are also used in electrical appliances, such as hair dryers and irons, to convert the voltage from the outlet to the level that can be used by the appliance.
The Bottom Line
Transformers are electrical devices that use inductive coupling to transfer electrical energy between two or more circuits.
They are used in various applications, such as power generation, transmission, and distribution; audio and video equipment; and electrical appliances.
It serves as either a step-up transformer or a step-down transformer to change the voltage level and as an isolation transformer to physically separate two circuits.
It is also a key component in the operation of electrical motors and generators.
FAQs
1. What is a transformer?
A transformer is an electrical device that uses inductive coupling to transfer electrical energy between two or more circuits.
How does a transformer work?
A transformer works by using inductive coupling to transfer electrical energy from the primary winding to the secondary winding.
3. What are the different types of transformers?
The different types of transformers are step-up transformer, step-down transformer, isolation transformer, auto transformer, and polarity transformer.
4. What is the purpose of a transformer?
The purpose of a transformer is to change the voltage level and/or to isolate two circuits.
5. What is the difference between a step-up transformer and a step-down transformer?
A step-up transformer increases the voltage from the primary winding to the secondary winding, while a step-down transformer decreases the voltage from the primary winding to the secondary winding.
