Performance of a custom high precision potentiometric device

The authors present the results of laboratory tests performed on an automatic high-precision device for voltage balancing. The system tested is based on an 18-bit D/A (digital/analog) converter and a dedicated null detector, both controlled by a personal computer. The high relative resolution allowed by the D/A converter is exploited by the system in different full-scale ranges (0.1-1-10 V). The relative resolution of balancing is equal to 3.8×10^-6, corresponding to the least significant bit of the 18-bit D/A converter used. The system has been implemented for the purpose of achieving high accuracy with low-cost components and short operating times. The experimental results are in accordance with design specifications, with no significant deterioration of metrological characteristics, especially the relative resolution of the D/A converter