Which device changes AC to AC?

Which device changes AC to AC?

• A. Rectifier
• B. Inverter
• C. Converter
• D. Transformer

Answer: (D)

AC to AC means changing the voltage level of an alternating current while keeping it as alternating current. The device that does this is a transformer. It works by magnetic induction between two windings on a shared iron core. When the primary winding carries AC, the current creates a changing magnetic field in the core, which induces an alternating voltage in the secondary winding. The amount of voltage you get on the secondary is set by the turns ratio between the windings, so you can step the voltage up or down as needed. The frequency stays the same (aside from small losses), which is why it’s still AC after the change. Rectifiers convert AC to DC, so they don’t produce AC-to-AC changes. Inverters convert DC to AC, so they require DC input. The term converter can refer to devices that switch between AC and DC, but it’s not the standard device for simply changing AC voltage levels without converting to DC.

AC to AC means changing the voltage level of an alternating current while keeping it as alternating current. The device that does this is a transformer. It works by magnetic induction between two windings on a shared iron core. When the primary winding carries AC, the current creates a changing magnetic field in the core, which induces an alternating voltage in the secondary winding. The amount of voltage you get on the secondary is set by the turns ratio between the windings, so you can step the voltage up or down as needed. The frequency stays the same (aside from small losses), which is why it’s still AC after the change.

Rectifiers convert AC to DC, so they don’t produce AC-to-AC changes. Inverters convert DC to AC, so they require DC input. The term converter can refer to devices that switch between AC and DC, but it’s not the standard device for simply changing AC voltage levels without converting to DC.