In referring to figure "E" of the illustration, what statement is true concerning the functional purpose of the coupling transformer? EL-0075 Illustration EL-0075: the U.S. Coast Guard has not released this illustration.

Correct Answer: Option A — The transformer functions as a filter by removing the DC component from the varying DC input to produce an AC output shifted 90 from the input.

The coupling transformer isolates DC components while transferring AC varying signals, introducing a 90-degree phase shift characteristic of inductive-reactive coupling networks in electronic circuits.