engleski

Stability of some DC Reference Standards

Some fifteen years ago, after eighty years of utilisation of the Weston cell as voltage standard, commercial designs of sources with Zener diodes, the so-called DC Reference Standards appeared on the market. They have much more favourable properties compared to Weston Standard Cells. The stability of one commercial DC Reference Standard Fluke 732A at the 10 V output was analysed in relation to the calibration data obtained in the Fluke, NIST and PTB laboratories during a period of seven years. Two approaches to accessible data for regression line calculation were compared. In the first approach all the data were taken into consideration, whereas in the second approach only the mean values of particular calibration expressed for the mean date were taken into account and were calculated with weights. Both approaches show a very good agreement. The voltage of the analysed source at the 10 V output changes for about 0.1×10-6/year, which is several times less than the value given in the manufacturer's specifications.

DC voltage standards; DC reference standards; voltage measurement; Zener diode standards; maintenance

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