An Automated System for the Comparison of Resistance Standards from 1 Ohm to Several kOhms

摘要

A current comparator resistance bridge has been used by the Fluke Primary Standards Laboratory for many years to compare resistance standards from 1 Ohm to 1 MOhm. This bridge provides excellent transfer uncertainties but requires a skilled technician to operate. When the workload is heavy this ties him up for many hours a day of tedious work. In addition the data must be manually entered into a computer for analysis and the printing of a report which is time consuming and subject to error. To overcome these problems for a large portion of the workload an automated system has been developed that can measure resistance ratios in the range of 1 Ohm to several kOhms with uncertainty as good as or better than the bridge but can be operated by a less skilled operator. This system uses a current source and an 8(1/2) digit DVM to measure the voltage across each resistor. The system includes a scanner to switch the meter and is capable of comparing one resistor with up to 10 other resistors. This paper describes the system and the results obtained using it.