The Measurement of Small Capacities 



89 



Va/ue o^ii^ Ccfr>. ''j 



Fig. 4b 



Relation between the Value of R/R' and the Reciprocal of the Distance x between the Plates 



of Guard-ring Condenser C_'. 



d = Distance between the Plates of Guard-ring Condenser C. 



Frequency f of supply = 1020. 



The values of h obtained from Fig. 4a and 4b are 1.18 cm. and 1.16 cm. 

 respectively. The leads are, of course, not the same as those of Method I, 

 for which the correction is much larger. 



When a curve connecting R/R' and 1/jchas been obtained, the capa- 

 city to be measured is substituted for the guard-ring condenser C, and 

 the same adjustments made. From the new value of R/R', the corres- 

 ponding value of Xjx may be found from the curve, and the capacity 

 calculated by means of the formula C'=A/47rx. 



The results of measurements on various types of insulators are given 

 in Table II. 



Table II. 

 Ordinary Suspension Type Insulator 



