Pilot study: Calibration of very high value resistors (>100 GΩ)

Project Description

INRIM has developed a method to calibrate very high value resistances by triangulation.
There are 2 public technical reports available:

• November 2022
  Analyses for equivalent ratio model in measurements of high standard resistancebridges
• November 2023
  Low–frequency noise analyzes in measurements of high standard resistance bridges
   

The LNE Low Frequency Electrical Metrology team has a very high value resistance calibration bench, based on the method of charging capacitor, traceable to SI and validated through EUROMET.EM-S24, EURAMET.EM-S32, EURAMET.EM-S44 comparisons.

The LNE-INRIM collaboration aims to calibrate the resistances of 10 TΩ, 100 TΩ and 1 PΩ by comparing the two approaches and reaching robust method for high value resistance calibration.
Further plans concern the measurements with other methods available at LNE and INRiM including ultra low current amplifiers at test voltages below 10 V.
These low voltages are situated usually in the range of the extrapolation value for the high value resistors. However, knowing the resistor values at 10 V and lower is necessary to scale up the calibration methods based on the modified Wheatstone bridge until 1 Pohm or higher.

The uncertainties related to the high value resistor calibrations depend on the applied voltages. Certain conditions are imposed to the triangulation method. The condition of the triangulation among 3 resistors is related to the lowest value of the standard deviation of the mean obtained for each ratio of resistors involved in the triangulation. This Pilot Study will generate a matrix of uncertainties where resistor values, respectively voltage values will trigger the lines and the columns of the matrix.