May 16, 2016
An automatic ratio bridge based on BVD is used to take measurement up to 1 GΩ at NIM. Adopting a “Virtual Null” mode efficiently reduces effects of insulation of bridge and offset current of detector. The measurement of a 100 MΩ Hamon resistor shows an agreement of 1 parts in 106 at ratio 1 GΩ:100 MΩ.