The transformer is a static electrical device that transfers energy through inductive coupling between its winding circuits. It converts alternating voltages from low to high levels or vice versa. Transformers range greatly in size and are used in applications from microphones to power stations. They operate on basic principles to transfer electrical energy between circuits without moving parts. Transformers that increase voltage are called step-up transformers, while those that decrease voltage are step-down transformers.

1. INTRODUCTION
The transformer is a device used for converting
a low alternating voltage to a high alternating
voltage or a high alternating voltage into a low
alternating voltage. It is a static electrical device
that transfers energy by inductive coupling between
its winding circuits. Transformers range in size
from a thumb nail sized coupling transformer
hidden inside a stage microphone to huge units
weighing hundreds of tons used in power plant
substations or to interconnect portions of the
power grid. All operate on the same basic
principles, although the range of designs is wide.
While new technologies have eliminated the need
for transformers in some electronic circuits,
transformers are still found in many electronic
devices. Transformers are essential for high
voltage electric power transmission, which makes
long distance transmission economically practical. A
transformer is most widely used device in both low

2. and high current circuit. In a transformer, the
electrical energy transfer from one circuit to
another circuit takes place without the use of
moving parts. A transformer which increases the
voltages is called a step-up transformer-. A
transformer which decreases the A.C. voltages is
called a step-down transformer-. Transformer is,
therefore, an essential piece of apparatus both for
high and low current circuits.