A transformer with two fixed secondaries

A capacitor for power factor correction

A current transformer with a 5 A secondary

TransformersQuestion 1108 of 1506

What is a Variac?

A transformer with two fixed secondaries
A capacitor for power factor correction
An autotransformer with a sliding tap
A current transformer with a 5 A secondary

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Correct answer: An autotransformer with a sliding tap

A Variac is a variable autotransformer. The sliding contact gives a fine, continuous voltage adjustment.

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

Practice transformers

Questions last reviewed: 18 October 2026

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