Notes on the Basic Working Principle of a Transformer

Introduction

• Topic: Basic working principle of a transformer.
• Key Principle: Works on the principle of mutual induction.

Mutual Induction

• Definition:
  • The principle of mutual induction states that when two coils are inductively coupled, a change in current in one coil induces an EMF in the other coil.
  • Inductively Coupled: Coils placed together without electrical connections.

Process of Induction

• Exciting One Coil:
  • Supplying power to one coil (the primary coil) induces EMF in the other coil (the secondary coil).

Basic Transformer Diagram

• Structure:
  • Consists of a magnetic core with two coils:
    • Primary Winding: Coil where supply is connected.
    • Secondary Winding: Coil where load is connected.

Magnetic Flux

• AC Supply:
  • Current through the primary winding generates magnetic flux (Φ) that passes through the magnetic core.
  • This changing magnetic flux links with both primary and secondary windings.

Faraday's Law of Electromagnetic Induction

• Self-Induced EMF:
  • Voltage induced in the primary coil due to its own supply.
• Mutually Induced EMF:
  • The same changing flux induces EMF in the secondary coil due to the primary coil's supply.
• When connected to a load, current flows through the secondary winding.

Symbolic Representation of Transformer

• Diagram Components:
  • AC supply -> Connected to Primary Winding.
  • Magnetic Core -> Links both coils.
  • Secondary Winding -> Connected to Load.
  • Variables: N1 (turns in primary) and N2 (turns in secondary).

Conclusion

• The principle of mutual induction is the fundamental working principle of transformers, allowing for the transfer of EMF from the primary to the secondary winding.