This is a Transformer which you see in the movie. I loved this movie so much, but today we will talk about the transformer used in our daily lives, especially in power supply.
The Transformer used in the power supply.
1. Transformer:
The transformer is a device used for converting low alternating voltage at high current into high voltage at low current and vice-versa, through mutual induction.
image from google
2. Principle of working:
It works on the principle of mutual induction i.e., if two coils are inductively coupled and when current or magnetic flux is changed through one of the two coils, then induced e.m.f is produced in the other coil.
3. It consists of two coils wound on the same core.
4. The alternating current passing through the primary creates a continuously changing flux through the core. The changing flux induces an alternating e.m.f(electromotive force) in the secondary. To minimise eddy currents, the soft iron core is laminated.
There are two types of transformer:
A) Step-up transformers:
In a step-up transformer, the number of turns in secondary coils(Ns) is greater than the number of turns in primary coils(Np) i.e., Ns > Np. It converts a low voltage at a high current into a high voltage at a low current.
primary coil=Np, secondary coil=Ns
Ns > Np in step-up transformer
B) Step-down transformers:
The number of turns in secondary coils(Ns) is less than that in primary coil(Np) i.e., Ns < Np. It converts a high voltage at low current into a low voltage at high current.
Ns < Np in step-down transformer
Losses in transformer:
In transformers, some power is always lost due to heating effect, flux leakage, eddy currents, hysteresis and humming.
1. Cu loss (I*IR):
when current flows through the transformer windings, some power is wasted in the form of heat (H=I*IRt).
2. Eddy current loss:
some electrical power is wasted in the form of heat due to eddy currents induced in core.
To minimise eddy current loss thin sheets of soft iron is used.
3. Hysteresis loss:
The alternating current flowing through the coils magnetises and demagnetises the iron core again and again. Therefore, during each cycle of magnetisation, some energy is lost due to hysteresis.
4. Magnetic flux leakage:
Magnetic flux produced in the primary winding is not completely linked with secondary because few magnetic lines of force complete their path in air only.
magnetic leakage in both primary and secondary coil.
5. Humming losses:
Due to the passage of alternating current, the core of the transformer starts vibrating and produces loss of electrical energy in the form of humming sound.
Uses of Transformer:
1. In voltage regulators for TV, refrigerator, computer, air conditioner etc.
voltage regulator for large voltage 
voltage regulator for small voltage
2. step down transformer is used in the induction furnaces.
3. step down transformer is used for obtaining large current for welding purposes.
4. In the transmission of a.c over long distance.
5. step down and step up transformers are used in electrical power distribution.
6. Audio frequency transformers are used in radiography, television, radio, telephone etc.
Thanks you guys for reading it. hope you enjoyed and gets some knowledge from it.
