Polarisation and Energy Loss in Dielectrics

The Paper discusses the relations which should exist between the coefficients in Pellat's equation (as modified by Schweidler) giving the displacement in a viscous dielectric as a function of the time of charge and the P.D. It is proved that where the polarisation current of a dielectric under the action of a steady E.M.F. is proportional to t-n (t=time), the viscous capacity of any group of molecules having the same time constant of displacement is proportional to the (1 - n)th power of the time constant. Starting with this hypothesis it is proved that under an alternating E.M.F. the energy loss varies as the nth power of the frequency, and the viscous capacity varies as the (n - 1)th power. An equation is also obtained giving the variation in capacity for the particular case in which n=1. Experimental results published by various investigators are given, and are shown to be not inconsistent with Pellat's modified theory. A brief resume of Pellat's Theory is also given.