A transformer works on the principle of electromagnetic induction. It consists of the primary coil and the secondary coil. Also, these coils are insulated from each other and coiled on a soft iron core. Next, we connect the alternating power supply with the primary coil and the output terminal with the secondary coil.
When we connect an AC source with the primary coil, it produces a fluctuating magnetic flux in the primary coil. Moreover, the iron core transfers this changing flux to the secondary coil, which induces emf in it.
In a step-up transformer, the secondary coil has more turns than the primary coil. Thus, the voltage increases. However, the current in the secondary coil is less than the primary coil.
In a step-down transformer, the primary coil has more turns than the secondary coil. Thus, the voltage steps down, and the current increases.
In these transformers, the coil surrounds the core. The primary and the secondary coils are on the side limbs.
In these transformers, the core surrounds the coil. The primary and secondary coils are in the central limb.
