KAMALA NIKETAN

MONTESSORI
CBSE SCHOOL
2024-2025

PHYSICS PROJECT
TRANSFORMER
SESSION 2023-24
 NAME: ATCHAYA J

CLASS: XII E

CONTENTS
 INTRODUCTION
 PRINCIPLE OF TRANSFORMER
 WORKING OF TRANSFORMER
 ENERGY LOSSES IN TRANSFORMER
 TYPES OF TRANSFORMER
 ADVANTAGES & DISADVANTAGES
 USES OF TRANSFORMER
 BIBLIOGRAPHY
 INTRODUCTION
Transformer is one of the most common devices found in
electrical system that links the circuits which are operating at
different voltages .These are commonly used in applications
where there is a need of AC voltage conversion from one
voltage level to another.
It is possible either to decrease or increase the voltage and
currents by the use of transformer in AC circuits based on the
requirements of the electrical equipment or device or load.
Various applications use wide variety of transformers
including power, instrumentation and pulse transformers.
In a broad, transformers are categorized into two types,
namely, electronic transformers and power transformers.
Electronic transformers operating voltages are very low and
are rated at low power levels. These are used in consumer
electronic equipments like televisions, personal computers,
CD/DVD players, and other devices.
The term power transformer is referred to the transformers
with high power and voltage ratings. These are extensively
used in power generation, transmission, distribution and
utility systems to increase or decrease the voltage levels.
However, the operation involved in these two types of
transformers is same. So let us go in detail about the
transformer.

PRINCIPLE OF TRANSFORMER
The main principle of operation of a transformer is mutual
inductance between two circuits which is linked by a
common magnetic flux. A basic transformer consists of two
coils that are electrically separated and inductive but are
magnetically linked through a path of reluctance. The
working principle of the transformer can be stood by the
figure.

.
In a good transformer, the whole magnetic flux linked with
primary coil is also linked with secondary and the induced
emf of both in each turn is equal.

WORKING OF TRANSFORMER
The transformer working depends upon Faraday's law of
electromagnetic induction.
According to Faraday's laws,
"The Rate of change of flux linkage with respect to time is
directly proportional to the EMF induced in a conductor or
coil".
Faraday's Law E= N dϕ /dt
Where,
E = Induced EMF
N = the number of turns
dϕ = Change in flux
dt = Change in time
CONSTRUCTION:
A transformer is made up of a rectangular iron core, two cells
and primary coil with two sides of P1 and P2 and a secondary
coil with two sides S1 and S2. Both these coils are insulated
from the ferromagnetic iron core.
The source of the alternative current is connected to the
alternate current is connected to the primary winding and
the output is obtained through the secondary winding
whichis connected in parallel to a resistance R.

WORKING:
It works on the alternating current only because on
alternating flux is required for mutual induction between the
two windings. When the AC supply is given to the primary
winding with a voltage of V1 an alternating flux Φ sets up in
the core of the transformer, which links with the secondary
winding and as the result of it, an emf is induced in it is called
mutually induced emf. The direction of the induced emf is
opposite to the applied voltage of V1. This is because of
Lenz’s law.
Physically, there is no electrical connection between the two
windings but they are magnetically connected. Therefore, the
electrical power is transferred from the primary to secondary
circuit through mutual inductance. The induced emf in the
primary and secondary coil depends upon rate change of the
flux linkage (Nd Φ/dt). d Φ/dt is the change of flux and is
same for both the primary winding is directly proportional to
the number of the turns in the secondary coil.
TRANSFORMER EFFICIENCY:
The efficiency of the transformer is defined as the ratio of
useful output power to the input power. The input and
output power are measured in the same unit. It’s unit is
either in Watts (W) or KW. It is denoted by η.

η = output power/ input power

η = output power/output power + losses

 (OR)
η = Input power-losses/input power

ENGERY LOSSES IN TRANSFORMER

Even though transformers are very efficient machines, they
do result in small energy losses due to four main reason.
FLUX LEAKAGE:
There is always some flux leakage because not all of the flux
due to primary passes through the secondary due to poor
design of core.
RESISTANCE OF WINDINGS:
The wire used for winding has some resistance so, energy is
lost due to heat produce in the wire.
 TYPES OF TRANSFORMER

STEP UP TRANSFORMER:
The secondary voltage of a step-up transformer is raised
from the low primary voltage. Because the primary winding
has fewer turns than the secondary winding in this sort of
transformer, the ratio of the primary to secondary winding
will be greater than one. Step-up transformer are frequently
used in electronics stabilizers, inverters, and other devices
that convert low voltage to a significantly higher voltage. A
step-up transformer is also used in the distribution of
electrical power. For applications connected to power
distribution, high voltage is necessary. In the grid, a step-up
transformer is used to raise the voltage level prior to
distribution.
Step-down Transformer:
The primary voltage is converted to a lower voltage across
the secondary output using a step-down transformer. The
number of windings on the primary side of a step-down
transformer is more than on the secondary side. As a result,
the overall secondary-to-primary winding ratio will always be
less than one. Step-down transformer are used in electrical
systems that distribute electricity over long distances and
operate at extremely high voltages to ensure minimum loss
and economical solutions. Step-down transformer are used
to change high-voltage into low-voltage supply lines.
The so produced electro-motive force can be explained with
the help of Faraday’s laws of Electromagnetic Induction
given:
e=−dϕdt
ep=−dϕpdt
es=−dϕsdt
By using the above equations we get :
es=NsNpep
The ratio Ns/Np= K is called transformation ratio.
The transformer formula is given by:
VpVs=NpNs
Where, Vp = primary voltage, Vs = secondary voltage,
Np = number of turns in the primary, Ns = number of turns in
the secondary.

DIFFERENT TYPES OF TRANSFORMER:

 ADVANTAGES & DISADVANTAGES

Advantages Disadvantages
Magical Power Conversion Energy Loss and Inefficiency
Efficient Energy Transmission Bulky and Heavy
Safety and Protection Heat Generation
Versatility and Adaptability Maintenance and Lifespan
Supporting Renewable Energy Environmental Impact

USES OF TRANSFOMRER
 In chemical engineering processes like electrolysis and
electroplating, a regulated flow of current is required
which is supplied through a transformer.
 Transformers are used for battery charging processes as
the voltage is to be maintained so that the internal battery
components are not damaged.
 Transformers help in providing high currents required for
melting and welding of steel and lower currents for cooling
during a steel manufacturing cycle.
 A transformer in a circuit breaker can help in starting and
stopping the flow of current with the help of a switch,
hence protecting from any other damage.
 Transformers are mainly used for controlling the power of
alternating current which helps in increasing the efficiency
and ultimately lowering electricity bills.

BIBLIOGRAPHY
 Class XII physics part I textbook
 Manual book
 My cbse guide
 Google
 https://www.wikipedia.org/
 https://aspiringyouths.com/
 https://collegedunia.com/
 https://www.geeksforgeeks.org/transformer/
 https://www.electronicshub.org/introduction-to-
transformers/
 https://www.allumiax.com/blog/types-of-transformer