What is a key characteristic of a constant current transformer?

A constant current transformer is specifically designed to maintain a steady output current regardless of variations in load or input voltage. This means that as the load connected to the transformer changes, the transformer adjusts its output to ensure that the current remains constant. This characteristic is particularly important in applications where a consistent current is required for the efficient operation of electrical equipment.

While voltage adjustment is an essential function of many transformers, a constant current transformer focuses on current output. Regulating frequency and the ability to operate on both AC and DC are not relevant to the definition and primary function of a constant current transformer. Thus, the ability to maintain a steady output current is the defining feature of this type of transformer, confirming why that is the correct answer.