Electrode Effects in the Measurement of Power Factor and Dielectric Constant of Sheet Insulating Materials

It is shown t h a t , aside f r o m t h e g u a r d ring t y p e of electrode which can only be used with certain special t y p e s of measuring circuit, t h e most a c c u r a t e results can p r o b a b l y be o b t a i n e d by t h e use of equal foil electrodes a n d m a k i n g proper allowance for t h e edge effects. F r o m t h e s t a n d p o i n t of convenience, m e r c u r y electrodes and foil electrodes of unequal size h a v e certain a d v a n t a g e s . It is believed t h a t t h e results obtained with these t w o t y p e s a r e also sufficiently a c c u r a t e for most purposes when t h e corresponding corrections are applied.