سوال ۱۸ کنکور ارشد مهندسی برق ۱۴۰۰

PASSAGE 1 (paragraph 2):

Usually, users of the power network expect stable voltage, as they do not want to worry about its fluctuations. If, for example, it is 12 V DC, then changes are expected to be rather small, 2-3% of the nominal value at the most. Freely available energy sources are rarely capable of providing such power supply conditions. Therefore, properly constructed voltage converters are used as the intermediary between these sources and the user.

The word "intermediary" in paragraph 2 is closest in meaning to ..........