A transformer is designed to convert an AC voltage of 220V to an AC voltage of 12V . If the input terminals are connected to a DC voltage of 220V, the transformer usually burns . why ?

Dear student,

Transformer refers to the static electromagnetic setting which can transfer power from one circuit to another one. In AC circuits, AC voltage, current and waveform can be transformed with the help of Transformers. Each transformation is usually to transfer from one circuit to another one by the way of electromagnetism, but it has no direct relation with this circuit. It also can be transformed through electromagnetism (electrical manner). This electromagnetism is known as auto-transformer.
Transformer plays an important role in electronic equipment. AC and DC voltage in Power supply equipment are almost achieved by transformer’s transformation and commutation. At the same time the electrical parameters transformed by transformer are not one but a few ones.