48 



BELL SYSTEM TECHNICAL JOURNAL 



is true both on alternating and direct-current circuits. If unidirec- 

 tional potential is applied this relation holds without regard to the 

 polarity or the magnitude of the impressed voltage so long as this 

 voltage does not make the potential across the film opposing the 

 flow of direct current greater than the voltage to which this film was 

 formed. 



In the case of asymmetrical cells connected in series-opposed 

 relation the expression is correct either when the positive plates 



kW 



Jl. 



-^s — 



200 MF 



© 



j2- 



2: 



CONDENSER OR 



C=- 



I0« 



COMBINATION OF CONDENSERS 

 OF UNKNOWN CAPACITY AND 

 EQUIVALENT SERIES RESISTANCE 



2TrF 



W 



I 2 



R=- 



W 



IaI 



CONNECTION OF CONDENSERS FOR MEASUREMENT 



®+ -d) ®+ -d) o± 



FILM 

 FORMING 

 ELECTRODE L-| 



CATHODE 



ELECTROLYTE 



SINGLE 

 ASYMMETRICAL CELL 



TWO CELLS 

 SERIES AIDING 



TWO CELLS 

 SERIES OPPOSING 



Fig. 5 — Determination of capacity and equivalent series resistance of electrolytic 

 condensers with 60-cycle alternating current superimposed upon a variable uni- 

 directional potential. 



of the two cells are connected together at the mid-point or when 

 the negatives are so connected. On direct current it applies for 

 series-aiding as well as for series-opposed connections. 



C1C2 



It will be recognized that the resultant capacity -rr^ 



is the 



Ci + a 



same as is obtained when two ordinary static condensers of values 

 Ci and C2 are connected in series. However, the internal distribution 

 of electrostatic charges in opposed electrolytic condensers is quite 

 different from that in series-connected static condensers, due to the 

 rectifying characteristic of the films. 



