102 EFFECT OF CAPACITY. 



This resultant current will differ in phase from the voltage, 

 but will lead by an angle depending on the relative 

 magnitude of the resistance and capacity. 



The charging current will be the component which is 

 one-quarter period in advance of the voltage, while the 

 energy current will be the component in phase with the 

 voltage. As in the case of an inductive circuit, the power 

 given to the circuit is the product of energy current and 

 voltage or the product of total current x total voltage x 

 cos <t>, when </> is the angle of lead of current and cos <j> is 

 the power factor of the circuit. 



The relation between these quantities is shown in diagram 

 form in Fig. 45, where OE is the total voltage and OC the 





SCALE OF AMPERES & VOLTS 

 ? . 1 , 6 . 8 , 1Q . 12 . V* 16 18 20 



FIG. 45. DIAGRAM OF VOLTAGE AND CURRENTS IN CIRCUIT, WITH CAPACITY. 



resultant current in the circuit. The charging current is 

 OCi, and the energy current OC e . 



The angle of lead is C e C, i.e., the angle between total 

 voltage and total current. 

 The values of the quantities represented are 

 Total voltage = E = 25 volts. 

 Energy current = OC ' = 20 amps. 

 Idle current = OC i = 2 * n KE = 5 amps. 

 Total current = OC= -y/20 2 + 5 2 = 20-6 amps. 

 Impedance of Circuit having Capacity. In the case of a 

 circuit with capacity as with self-induction, the impedance or 

 apparent resistance is the value of the fraction 

 voltage of circuit 

 current in circuit 



and in this case also the impedance, or apparent resistance, 

 is always greater than the true, or ohmic, resistance. 



Its value may be obtained by drawing a triangle of 

 impedance similar to that obtained on page 35 for an induc- 

 tive circuit. The components of the impedance at right 



