112 



EFFECT OF CAPACITY. 



across both ammeter and condenser, if the voltmeter takes 

 current which might affect the ammeter readings. 



Throughout the experiment keep the frequency 

 constant, and vary the voltage at the condenser terminals. 

 For each value of the voltage read the value of the 

 current. 



Enter readings in tabular form. A curve should be 

 plotted with voltage horizontal and charging current 

 measured vertically. 



Fig. 52 shows the curve plotted from a set of 

 readings obtained with a 20 microfarad condenser at 54 

 periods per second. Again the results give a straight line, 

 showing that the charging current varies in direct 



-5 



20 40 60 80 100 120 



Volts. 



Via. 52. VARIATION OF CHARGING CUKBKNT, WITH VOLTAGE. 



proportion to the voltage applied to the condenser. As 

 these readings were taken with an alternator giving a 

 sine wave form, a similar calculation might be made to 

 confirm the results as given in the case of the previous 

 experiment. 



Measurement of Power in a Circuit possessing Capacity. 

 From what has already been said, it will be apparent that 

 the power in a circuit possessing capacity cannot be 

 determined by a simple measurement of the current and 



