ALTBRNATINQ-CURRBb T CIRCUITS 



29 



15. Circuit Containing Capacitance Only. When a direct - 

 current voltage is impressed across the j)l:ites of a condenser. 

 ( Vol. I, ( 'hap. I X there \S an initial rush of current which charges 

 the condenser to line potential. After this there is no further 

 How of current if the line voltage remains constant. If the con- 

 r plates now are short-circuited, making the voltage across 

 the plates :/>m, current flows out of the condenser. 



Figure 2X(f/) shows an alternating voltage E impressed across 

 the plates of a condenser C. When the voltage starts from its zero 

 value at a, Fig. 28(6), and increases positively, current flows into 



(a) 



, L'S. Cirriiit rontaininu upantaticv only. 



Ondenser, Therefore, this current is positive. As long GU9 

 tlie voltage across the condenser plates continues to increase, 

 current mu-t llow into the condenser from the positive wire and 

 thi- current will he positive in sign. When point h is reached, 

 the incivax- of vnlt:i_ d the current becomes zen. 



lietween // and r the voltage is deep that current is 



flowing out of the condenser into the positive line, and as the 

 current flow h led, tin- <\<r\\ of the current is ; itive. 



U98ee thru:h z-n> at C, the en if. i< nefjat ive and d. 



i in the o|)posite direction. BO the current -nil 

 remiii' T\\\> continues until the volt a tie n-acl 



maximum. A' thi.- point the current - and 



Q I.eeon: 



An examin I hat when an alternating 



a condeiivr!-, the rurreni into Hi 



