MAGNETRON AS GENERATOR OF CENTIMETER WAVES 



199 



acteristic of the operating magnetron is the V-I plot or performance chart. 

 In Fig. 17 such a chart is plotted for the same magnetron'^ used as the ex- 

 ample for Fig. 16. In it are plotted contours of constant magnetic field, 

 RF power output, and over-all efficiency. The fact that the constant mag- 



CONSTANT MAGNETIC FIELD-GAUSS 



CONSTANT POWER OUTPUT- KILOWATTS 



CONSTANT OVERALL EFnCIENCY 



I TYPICAL OPERATING POINT 



8 12 16 20 24 28 32 



DC CURRENT, I, IN AMPERES 



Fig. 17. — A V-I plot or performance chart for a magnetron having eight resonators 

 (see footnote 16). Contours of constant magnetic field, power output, and over-all effi- 

 ciency are shown. The typical operating point plotted is that specified in footnote 16 and 

 plotted in Fig. 16. 



netic field contours are nearly horizontal and spaced as they are is a mani- 

 festation of the oscillation conditions of equations (15) and (16). The in- 

 crease of voltage with current is an effect, attributable to the space charge, 

 quite independent of the condition of synchronism between field and elec- 



