Explain the difference between a transformer and a transformer-rectifier unit in aircraft power.

Explain the difference between a transformer and a transformer-rectifier unit in aircraft power.

• A. A transformer adjusts voltage levels; a transformer-rectifier unit both steps voltage and rectifies AC to DC for the DC buses.
• B. A transformer converts DC to AC.
• C. A TRU only steps voltage, not rectifies.
• D. They are identical.

Answer: (A)

In aircraft power systems, DC power is needed for the DC buses, so the transformer-rectifier unit is used to convert AC to DC after shaping the voltage. A transformer by itself only handles AC; it changes the voltage level of the alternating current and provides isolation, but it does not produce DC. The transformer-rectifier unit combines that voltage-changing function with rectification and filtering, turning the stepped-down AC into a stable DC output for the DC buses (often with some regulation to hold a steady voltage). This is why the correct description says that a transformer adjusts voltage levels, while a transformer-rectifier unit both steps voltage and rectifies AC to DC for the DC buses.

In aircraft power systems, DC power is needed for the DC buses, so the transformer-rectifier unit is used to convert AC to DC after shaping the voltage. A transformer by itself only handles AC; it changes the voltage level of the alternating current and provides isolation, but it does not produce DC. The transformer-rectifier unit combines that voltage-changing function with rectification and filtering, turning the stepped-down AC into a stable DC output for the DC buses (often with some regulation to hold a steady voltage). This is why the correct description says that a transformer adjusts voltage levels, while a transformer-rectifier unit both steps voltage and rectifies AC to DC for the DC buses.