Question

Explain why a transformer doesn't work with DC.

Answer 1

Voltage is induced in the secondary coil when magnetic flux linking to the secondary coil is time-varying due to current in the primary coil of the transformer.

But, as we know that the current in DC source is constant and also there is no relative motion between the coils of the transformer, therefore emf is not induced in the secondary coil of the transformer. In this way the transformer fails to transfer the electric power from the primary to the secondary coil.

Hence, a transformer doesn't work with DC source.