Evaluation of the NBS unit of resistance based on a computable capacitor
Robert D. Cutkosky · Journal of Research of the National Bureau of Standards Section A Physics and Chemistry · 1961
An e valuat ion of t he uni t of resistance ma in tain ed at t he Natio na l Burea u of Stan da rds, based on t he prototype stand a rds of le ngt h and t ime, is d escribed.The evalu at ion is based o n a no min ally one-picofa ra d ca p a ~i tor whose valu e m ay be calc ul a ted fro m its mec ha nical dimen.lio ns to hig h acc uracy.This capac ito r is used to calibrate a n O.Ol-micl"Ofar ad capacito r.A fr equency-dep enden t bridge in volving t his ca pac itor e~tab li s h es t he value of a lO'-ohm resisto r.Co mpa rison of t hat re.;istor wi t h t he ba nk of o ne-o hm res isto rs maintaining t he NBS uni t of resista nce es ta blis hes t hat t his unit is flB U= l.000002 3 ohms ± 2.1 ppm.Th e in d ica ted un certa in ty is an est imated 50 percent error of t he repo rted value based on t he s tat io t ica l uJl certain ty o f t he meas urements a nd a ll owin g for kn own so urces of p ossible sys te mat ic errors ot her t han in t he sp eed of li g ht , a ss uming t ha t t he speed o f li g ht c = 2.997925 X J QIO c m/sec.