Red Seal Electrician Practice
TransformersQuestion 1106 of 1506

Compared with a regular isolating transformer doing the same boost or buck job, what is the main advantage of an autotransformer?

  1. It isolates the load from the line.
  2. It is cheaper and lighter to make.
  3. It can change the frequency.
  4. It has no losses.
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Correct answer: It is cheaper and lighter to make.

It needs only one winding, so it uses less copper. The price is that it gives no isolation.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 10.5: Winding Configurations

Practice transformers

Questions last reviewed: 18 October 2026