Estimation of uncertainty in measurement in precision calibration of DC high current source up to 100 A

Abstract

In the present paper, calibration of precision DC high current source (> 2 A and up to 100 A), widely used in industries and research, has been discussed as case studies of transconductance amplifier and precision power supply calibration. Since transconductance amplifier requires boosting device for its operation, therefore effect of boosting device was added as an additional component of uncertainty. The various sources of uncertainty in measurement and their estimation based on Type A and Type B method as per ISO ‘GUM’ document are discussed in detail. The results are reported at coverage factor k=2 for approx 95% confidence level. The standards used for calibration are traceable to the ‘National Standards’ and their uncertainties were evaluated prior to use to avoid variation in results due to drift.