Which current uses transformers?

Which current uses transformers?

• A. DC
• B. Pulsating DC
• C. AC
• D. AC and DC

Answer: (C)

Transformers transfer energy between windings through changing magnetic flux in the core, which is produced by alternating current. When current continually reverses, the magnetic field keeps changing and induces a voltage in the secondary winding according to Faraday’s law. Direct current, once any initial surge settles, becomes steady and the magnetic field becomes constant. With a constant field, there’s no changing flux to induce a new voltage, so energy isn’t transferred effectively through a transformer. Pulsating DC still has a DC component and is not a clean AC signal; while it contains momentary changes, the presence of a DC offset can push the core toward saturation and cause heating, making transformers unreliable for that kind of source. Therefore, the current type that properly uses transformers in standard practice is alternating current.

Transformers transfer energy between windings through changing magnetic flux in the core, which is produced by alternating current. When current continually reverses, the magnetic field keeps changing and induces a voltage in the secondary winding according to Faraday’s law.

Direct current, once any initial surge settles, becomes steady and the magnetic field becomes constant. With a constant field, there’s no changing flux to induce a new voltage, so energy isn’t transferred effectively through a transformer.

Pulsating DC still has a DC component and is not a clean AC signal; while it contains momentary changes, the presence of a DC offset can push the core toward saturation and cause heating, making transformers unreliable for that kind of source.

Therefore, the current type that properly uses transformers in standard practice is alternating current.