An electric transformer is a device that is used to transfer electrical energy from one circuit to another circuit, without any direct electrical connection between them. The basic principle behind the operation of a transformer is electromagnetic induction, where a changing magnetic field induces an electrical current in a nearby conductor.
Transformers are used to either step-up or step-down the voltage of an alternating current (AC) power supply. A step-up transformer increases the voltage of the input power supply, while a step-down transformer decreases the voltage. This is important for the efficient transmission of electrical energy over long distances, as high voltage reduces energy loss due to resistance in transmission lines.
Transformers consist of a core made of a magnetic material, such as iron, and two coils of wire wrapped around the core. The coil connected to the input power supply is called the primary coil, while the coil connected to the output circuit is called the secondary coil. When an alternating current flows through the primary coil, it creates a changing magnetic field that induces a current in the secondary coil.
The ratio of the number of turns in the primary coil to the number of turns in the secondary coil determines the voltage transformation ratio. For example, a transformer with 1000 turns in the primary coil and 100 turns in the secondary coil will step-down the voltage by a factor of 10.