• 

 230 



ANNALS NEW YORK ACADEMY OF SCIENCES 



beginning of oscillation. When the audion begins generating, the grid 

 oscillations are continuously rectified to charge the grid condenser, and 

 this charge continuously leaks off either by way of the grid or by means 

 of a special high resistance placed in shunt with the condenser. As the 

 negative charge builds up in the grid condenser, it decreases the average 

 value of the continuous current component of the wing current, and 

 therefore limits the amplitude of the oscillations of the grid circuit until 

 a point is finally reached where the rate at which electricity is supplied 

 to the grid condenser is just equal to the rate at which it leaks off. Con- 



M!MBH\!\l\i^ 



GEID 

 POTENTIAL 



"WING 

 CURRENT 



TELEPHONE 

 CURRENT 



Fig. 24 



sider now the effect on the system of an incoming continuous wave hav- 

 ing a frequency slightly different from the frequency of the local oscil- 

 lations. The presence of the local oscillations will not in any way inter- 

 fere with the amplifying powers of the system, and the incoming oscilla- 

 tions will build up in exactly the same manner as for the non-oscillating 

 state, but to a greater degree, because of the closer grid and wing coup- 

 ling. Simultaneously with the amplifying of the incoming wave, beats 

 are produced between the local and the signaling currents, the efiEect being, 

 alternately to increase and decrease the amplitude of the oscillations lU' 

 the system. From Fig. 23 it will be apparent that when this steady 



