Working Principle of Transformer

WORKING PRINCIPLE OF A TRANSFORMER

Whenever the primary winding is connected to an a.c source an exciting current flows through the primary winding. Since the current is alternating, it will produce an alternating flux in the core which will be linked by both primary and secondary windings. The induced emf in the primary winding is (E₁) is almost equal to the applied voltage V₁ and will oppose the applied voltage. The emf induced in the secondary winding (E₂) used to deliver power to any load connected across the secondary side of the transformer.

Thus power is transferred from the primary to the secondary circuit by mutual induction. The frequency of induced emf in secondary is same as that of the supply voltage. The magnitude of the emf induced in the secondary winding will depends upon its number of turns.

Step Down Transformer: Number of turns in the secondary winding is less than primary winding, shown in Figure 1.2.

Step Up Transformer: Number of turns in the secondary winding is higher than primary winding, shown in Figure 1.3.