Transformer Working - Alternating Current, Physics, Class 12

A transformer is an electrical device that transfers electrical energy from one circuit to another through electromagnetic induction. It is commonly used to increase or decrease the voltage of an alternating current (AC) power supply.

Working Principle:
The working principle of a transformer is based on Faraday's law of electromagnetic induction. According to this law, when the magnetic flux linked with a coil changes, an electromotive force (EMF) is induced in the coil. In a transformer, this is achieved by using two coils, known as the primary and secondary coils, which are wrapped around a common iron core.

Construction:
- The primary coil is connected to the input source, while the secondary coil is connected to the output load.
- The core is made of laminated iron to minimize eddy current losses and increase the efficiency of the transformer.
- The windings of the coils are insulated to prevent short circuits and are wound in such a way that they are tightly coupled to each other.

Working:
1. Step-up Transformer: In a step-up transformer, the number of turns in the secondary coil is greater than the number of turns in the primary coil. This results in an increase in voltage from the primary to the secondary coil. The primary coil is connected to an AC source, which creates an alternating magnetic field in the core. This changing magnetic field induces an EMF in the secondary coil, which is then used to power the load.

2. Step-down Transformer: In a step-down transformer, the number of turns in the secondary coil is less than the number of turns in the primary coil. This results in a decrease in voltage from the primary to the secondary coil. The primary coil is connected to an AC source, and the changing magnetic field induces an EMF in the secondary coil, which is then used to power the load.

Key Points:
- A transformer works on the principle of electromagnetic induction.
- It consists of two coils, primary and secondary, wrapped around a common iron core.
- Step-up transformers increase the voltage, while step-down transformers decrease the voltage.
- Transformers are used in power transmission, electrical distribution, and various electronic devices.
- The efficiency of a transformer is determined by the core material and design.

Conclusion:
Transformers play a crucial role in electrical power systems by enabling efficient transmission and distribution of electrical energy. Understanding the working principle of transformers is essential for students studying physics, particularly in the context of alternating current. By following the guidelines mentioned above, you can create visually appealing content that effectively explains the working of transformers to students.