A transformer is a device that transfers electrical energy between two circuits through electromagnetic induction. It consists of two coils wound around an iron core. The primary coil is connected to a power source and the secondary coil is connected to a load. An alternating current in the primary coil induces a magnetic field that links to the secondary coil, inducing voltage in it. There are step-up transformers, which increase voltage, and step-down transformers, which decrease voltage. Transformers are used efficiently in the national power grid to transmit electricity over long distances at high voltages to reduce energy loss, before stepping voltages back down for safe distribution to homes.

1. Transformers
BY MOHAMMADIBRAHIM

2. • Introduction to transformers
• What are they made up of
• Their working process
• Types of transformers
• Explaining them
• Important keynotes
• Important equations regarding transformers
• The national Grid

3. What is a transformer?
1)A transformer is a device that changes potential
difference (voltage) from one value to another value
making it smaller or greater using the principle of
electromagnetic induction. 2) A transformer is an
electrical device that transfers electrical energy
between two or more circuits through
electromagnetic induction. A transformer may
increase or decrease voltage depending on the
number of turns of coils that you include.

4. What does it consist of?
A transformer consists of two coils wound on a soft
iron core. One of the coils is connected to a mains
power supply (gets supplied alternating current) is
known as primary coil while the other is connected to
any load (component Eg. Lamp) is known as secondary
coil. These coils must be separated from each other.
Here is a diagram
illustrating this…

5. Working Process of a Transformer:
The changing alternating current in primary
coil produces a changing (alternating)
magnetic field which link through the soft iron
core from primary to secondary coil.

6. There are two main types of transformers:
Step up Transformer
Step down transformer

7. Step up transformer:
A step up transformer is a type of transformer that
increases voltage from primary to secondary (more
secondary winding turns than primary winding
turns) is called a step up transformer.

8. Step-down transformer:
A step down transformer is a type of transformer that
decreases voltage from primary to secondary (less
secondary winding turns than primary winding
turns) is called a step up transformer.

9. A.C GRAPH: If the input in the primary coil is
A.C then the output mustbe
A.C

10. A video illustrating A.C in a transformer

11. THE FOLLOWING IS THE SYMBOL FOR A TRANSFORMER
The following are real pictures of transformers

12. Transformers are very efficient devices, if we assume they are 100%
efficient (no energy wasted), then the electrical input power will equal
the electrical output power.
CALCULATING THE POWER OF A TRANSFORMER.

13. Efficiency is never 100%, although it can be 99%. Energy is lost if some of the primary magnetic
field does not pass through the secondary.
Energy is also lost because some eddy currents are induced in the soft iron core as well as in the
coil. These eddy currents can by reduced by making the core laminated from thin metal strips.
SOLID CORE LAMINATED CORE
With no laminations with laminations
High eddy currents low eddy currents

14. The equation for finding the voltage or the number of turns of coil
in the primary/secondary coil.

15. Solving equations:
A transformer has 100 turns in the secondary coil. It steps up a voltage
from 50 to 240 volts. Calculate the number of turns in the primary coil.
After rearranging the formula
Answer=100 turns in the primary coil

16. A keypoint :
Increasing the turns of coil results in:
More Voltage
Less current
Decreasing the turns of coil results in:
Less Voltage
More current

17. What is The National Grid?
The national grid consists of transformers and high voltage cables. The national grid
connects the power stations to the homes. Energy is always lost in the power cables,
the bigger the distance between the power stations and the homes, the greater the
energy loss. We can use electricity to transform energy from the power cables to the
homes with less energy loss. First the electricity passes through step up transformers
which increase the voltage, therefore the current will be less, less heat will be
produced, and the energy loss will decrease. However, the voltage will be so high
and that cant pass in our homes, so we use step down transformers which decrease
the voltage.