# Do Transformers Only Work with AC

Transformers are primarily designed to work with alternating current (AC) electricity. Transformers function based on the principles of electromagnetic induction, which involves changing magnetic fields and the flow of alternating current.

## Do Transformers Only Work with AC

Here’s how a transformer works with AC electricity:

1. Input Coil (Primary Coil): The primary coil of a transformer is connected to the AC power source. As the AC current flows through this coil, it creates a changing magnetic field around it. The direction and strength of this magnetic field change in sync with the alternating current.
2. Output Coil (Secondary Coil): The secondary coil of the transformer is placed in close proximity to the primary coil, often sharing the same magnetic core. The changing magnetic field induced by the primary coil also affects the secondary coil.
3. Electromagnetic Induction: Due to electromagnetic induction, the changing magnetic field produced by the primary coil induces a voltage in the secondary coil. The induced voltage in the secondary coil is proportional to the rate of change of the magnetic field and the number of turns in each coil.
4. Voltage Transformation: If the secondary coil has more turns than the primary coil, the induced voltage in the secondary coil will be higher than the voltage applied to the primary coil. Conversely, if the secondary coil has fewer turns, the voltage will be lower. This property allows transformers to step up (increase voltage) or step down (decrease voltage) the AC voltage.
5. Isolation and Impedance Matching: Transformers also provide electrical isolation between the primary and secondary circuits. This isolation is valuable for safety and can also serve to match the impedance between different parts of an electrical system.

Because transformers rely on the changing magnetic fields associated with AC current to induce voltage in the secondary coil, they are not suitable for use with direct current (DC) electricity. In a DC circuit, there is no continuous change in current direction, which means there are no alternating magnetic fields to induce voltage in the secondary coil.

However, there are devices known as DC-DC converters or choppers that can convert DC voltage to different DC voltage levels, similar to how transformers work with AC. These devices use semiconductor switches and inductors to achieve voltage transformation in DC circuits.