Completely automated system for capacitance measurement through new accurate capacitance box

摘要

Capacitance boxes (CBs) are extensively used in electrical laboratories for calibration of capacitance measurement devices. In this paper, a new recently fabricated CB has been presented to be used for automatic calibrations through its 4096 output capacitance steps in the range from 100?nF to 150?μF. Full specifications and characterization of this new CB have been investigated in detail including its frequency and voltage dependences. The presented CB has relative accuracy in the range from ±5?×?10sup?5sup/ to ±5?×?10sup?4sup/, whereas the relative uncertainty due to the combination effect is less than 15?ppm. The described CB has been used to construct fully automated capacitance measurement system at the National Institute of Standards (NIS), Egypt, using Andeen-Hagerling 2700A, opt. E & opt. C, Ultra-precision Capacitance Bridge up to 1?μF. The second fully automated system for capacitance measurements is formed at NIS by An Agilent E4980A LCR meter, which is used to measure and characterize the higher capacitance values of the fabricated automated CB. Technical comparison between a previous CB and the new introduced one has been done to evaluate its performance.