ANALYZER FOR COMPLEX ELECTRIC WAVES 



243 



TU without exceeding the same percentage of error, or up to 60 TU 

 with 1 per cent error due to undesirable modulation in the current 

 analyzer. 



Reliability. Use of the heterodyne current analyzer over a period 

 of two years has proven it to be one of the most reliable means for 

 making measurements. With proper maintenance, which consists 

 only in maintaining constant "A" and "B" battery voltages and grid 

 voltage, and with proper precautions as to shielding and balance, 

 readings can be taken with a precision of 2 per cent. 



Vacuum Tube Curves Obtained ivith Heterodyne Current Analyzer. A 

 number of curves have been added to illustrate the application of the 

 current analyzer, though of course these represent only a small part of 

 the field of usefulness for which it is adapted. 



SINGLE TUBE AMPLIFIER 

 "o"TUBE: 113013 



OUTPUT OF FUNDAMENTAL, 2ND AND 3RD 



HARMONICS INTO 3000'*' AND 16000'^ LOADS. 



ETb =240 



-Gr = 60 



.4 5 

 a. 



.3 ° 



I/) 

 lu 



.2 fc 



.1 d 



I& 20 24 



MILLIAMPERES 



26 32 3<i 40 

 INPUT INTO (bOO**' 



Fig. 11 



The first set of curves, shown in Fig. 11, were taken on an "O" tube 

 (104"D) to show how the fundamental current and the second and 

 third harmonics produced in the tube changed with increase in the 

 input amplitude of a single frequency. Two sets of curves are shown 

 which were taken for two values of load impedance, one being equiva- 

 lent to the normal tube impedance and the other being six times as 

 large. The output currents have all been computed to show the equiv- 

 alent output into 600 ohms which is a common reference standard of 

 impedance used in telephone work. 



