A 1-100 build-up resistor for the calibration of standard resistors

The build-up resistor consists of eleven 10 Ω resistors permanently connected in series. Each resistor is defined as a four-terminal resistor. Groups of resistors can be connected in parallel or in series-parallel by separately connecting the appropriate current and potential terminals. The resistances of the combinations so obtained are independent of the resistances of terminal blocks and paralleling connectors to within 1 part in 108. The ratio of the series to the parallel resistance of ten coils is within 1 part in 108 of its nominal value (100) provided the individual coils are adjusted to equality within 1 part in 104. An example is given of the use of the build-up resistor to determine 10 and 100 Ω standard resistors in terms of a 1 Ω resistor to an accuracy of about 2 parts in 107. The build-up resistor can also be used as a pair of bridge ratio arms in which the ratio, which is nominally 10, can be determined accurately.