Why do Transformer works only with AC not with DC?


Transformers operate exclusively on alternating current (AC) rather than direct current (DC) because of the fundamental concept of electromagnetic induction.

The basic function of a transformer is to transmit electrical energy from one circuit to another via mutual induction between two coils (or) windings, known as the primary and secondary coils. When an alternating current passes through the primary coil, it creates a fluctuating magnetic field surrounding it. In accordance with Faraday’s law of electromagnetic induction, the changing magnetic field causes an electromotive force (EMF) (or) voltage to be generated in the secondary coil.

In DC circuits, though, the current runs continuously in one direction, resulting in a steady magnetic field. A continuous magnetic field does not cause a voltage to be generated in the secondary coil since magnetic flux does not fluctuate over time. As a result, transformers are incompatible with direct current.

To use transformers with direct current, additional parts such as a rectifier or inverter are necessary to convert DC to AC or vice versa, allowing the alternating current required for transformer operation. This is frequent in equipment such as inverters utilized in power electronics (or) specific types of power supply systems.

The direction of current flow is changed in AC. When AC flows through the primary, current is induced in the secondary due to mutual induction. There is no mutual induction in DC as its direction does not change. So a transformer cannot work in DC. Very helpful and we are using this in our Lesco online bill services