The construction of artifact standards of impedances aim to reach some goals. Some of the properties that define an impedance standard are listed below.
accuracy class The impedance value of the standard (as given by a calibration) should not be too far from its nominal value, determined by its construction. The nominal value can be printed on the standard itself, or determined (for decade boxes) by the dial settings, see Fig. 8.1. The accuracy class of a standard is typically expressed as the maximum permissible deviation of the true value with respect to the nominal value, in percentage.