Why dont transformers work with a DC supply ?

Transformers do not work with a DC supply primarily because they rely on the principle of electromagnetic induction, which requires a changing magnetic field. In AC (alternating current) systems, the voltage continuously alternates in polarity and magnitude, causing the magnetic field in the transformer’s primary winding to continually change. This changing magnetic field induces a corresponding alternating voltage in the secondary winding through electromagnetic induction. However, in a DC (direct current) supply, the voltage remains constant in polarity and magnitude, resulting in a steady magnetic field that does not vary over time. As a result, there is no fluctuating magnetic field to induce a voltage in the secondary winding of the transformer. Thus, transformers are ineffective when connected to a DC supply because there is no alternating magnetic field to facilitate the transformation of voltage levels.

DC supply is not used in transformers because of the fundamental requirement of transformers to operate based on electromagnetic induction, which necessitates a varying magnetic field. In DC systems, the absence of alternating current means there is no alternating magnetic field to induce voltage in the secondary winding of the transformer. This lack of induced voltage makes transformers ineffective for stepping up or stepping down DC voltages, as they cannot perform the voltage transformation function without the alternating magnetic flux essential for electromagnetic induction.

A transformer cannot be connected to a DC source because it requires an alternating current to function correctly. The core principle of operation for a transformer is based on the interaction between a changing magnetic field (produced by alternating current) and the coils of wire wound around an iron core. When an alternating current flows through the primary winding of the transformer, it creates a varying magnetic field in the core. This varying magnetic field induces an alternating voltage in the secondary winding through electromagnetic induction. In contrast, a DC source produces a constant magnetic field that does not vary over time, resulting in no induction of voltage in the secondary winding. Therefore, attempting to connect a transformer directly to a DC source would not result in any voltage output in the secondary winding, rendering the transformer non-functional for voltage transformation purposes.

Transformers work with AC but not DC because AC produces a continuously changing magnetic field due to its alternating voltage. This changing magnetic field induces a corresponding voltage in the secondary winding of the transformer through electromagnetic induction. The alternating nature of AC voltage ensures that the magnetic flux in the transformer core continually changes direction and magnitude, facilitating efficient voltage transformation. In contrast, DC voltage does not alternate; it remains constant in polarity and magnitude. As a result, there is no alternating magnetic field generated in the transformer core when connected to a DC supply, leading to no induction of voltage in the secondary winding. Thus, transformers are designed and optimized for AC operation to perform their intended function of voltage transformation effectively.

A transformer cannot work on a DC supply due to the absence of an alternating magnetic field necessary for electromagnetic induction. In a transformer, AC current in the primary winding creates an alternating magnetic flux in the core, which induces a voltage in the secondary winding. This induction process relies on the rapid changes in magnetic flux direction caused by the alternating current. In contrast, a DC supply produces a steady, unidirectional current, resulting in a constant magnetic flux in the transformer core. Without the alternating flux, there is no induced voltage in the secondary winding. Therefore, transformers are specifically designed to operate with AC supplies and cannot function properly when connected directly to DC sources.

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