circuit, other than a measuring circuit, required for the operation of the instrument, mõõtevahendi tööks vajalik ahel, elements and connections of an auxiliary device within the meter case intended to be connected to an external device, arvesti korpusesisesed elemendid ja ühendused, mis on ette nähtud välisseadmetega ühendamiseks, circuit which is usually energized by the auxiliary supply, vooluring, mida tavaliselt toidab abitoide, circuit, other than a measuring circuit, required for the operation of the recorder/instrument