Transformer vs. Coupled Inductor

Definition: Transformer uses a non gap magnetic core to convert voltage between primary and secondary coils and delivers power at real-time. Coupled inductor uses a gapped magnetic core to coverts voltage between primary and secondary coils and delivers power at controlled time intervals.

Key Difference

• Transformer does not store energy in its core.
• Coupled inductor stores energy in its core .
  • Note: energy is stored as magnetic flux inside the magnetic core gap.

Application

• Transformer is used in AC to AC conversion such as stepping down the AC wall outlet voltage from 120Vac to 24Vac.
• Coupled inductor is used in DC to DC converter such as flyback converter to step down 24V DC to 5V DC.