Title :
Model tests of electrical compensation method for the new calculable cross capacitor at NIM
Author :
Lu, Huang ; Small, G.W. ; Lu Zuliang ; Fiander, J.R. ; Yan, Yang
Author_Institution :
Nat. Inst. of Metrol., Beijing, China
Abstract :
In a cross capacitor with guard electrodes, the equivalent electrical length is sensitive to any variation in the cross section of the main electrodes unless measures are taken to compensate for this. The problem arises particularly in the case of a moveable guard electrode, which is conventionally fitted with a nosepiece of such geometry as to compensate for variations in the geometry of the main electrodes from one guard position to another. In the new NIM cross capacitor an alternative approach, in which a fraction of the measuring voltage is applied to an isolated electrode in the face of the guard electrode, has been investigated. Results indicate that this active nosepiece performs better than an equivalent geometrical compensating nosepiece.
Keywords :
capacitance measurement; capacitors; compensation; electrodes; geometry; voltage measurement; NIM; cross capacitor; electrical compensation method; equivalent electrical length; equivalent geometrical compensating nosepiece; model testiing; moveable guard electrode; nosepiece fitting; voltage measurement fraction; Bars; Capacitance; Capacitance measurement; Capacitors; Electrodes; Face; Voltage measurement; Close approach nonlinearity; Electrical end; End-effect error; Modified active nosepiece; Nosepiece;
Conference_Titel :
Precision Electromagnetic Measurements (CPEM), 2012 Conference on
Conference_Location :
Washington, DC
Print_ISBN :
978-1-4673-0439-9
DOI :
10.1109/CPEM.2012.6251003