ARAISTRONG, OPERATING FEATURlh'^ OF THE AUDION 



229 



The Audion as a Generator and Beat Receiver 



Any repeater, which is also an energy amplifier, may be used to pro- 

 duce continuous oscillations by transferring part of the energy in the 

 circuit containing the battery back to the controlling circuit to keep the 

 latter continuously excited. By providing a close enough coupling be- 

 tween the grid and wing circuits, sufficient energy" is supplied to the grid 

 circuit to keep it in continuous oscillation, and as a consequence thereof 

 oscillations of similar frequency exist in all parts of the system. The 



GRID CIRCUIT 

 CURKEXT 



GRID 

 POTENTIAL 



-'^iM/ilP 



WWliWl/l/' 



TELEPHONE 

 CURRENT 



frequency of these oscillations is approximately that of the closed grid 

 circuit if the tuning condenser of that circuit is large with respect to the 

 capacity of the audion. If this capacity is small, then the wing circuit 

 will exert a greater influence on the frequency of the system, and it will 

 not approach that of the grid circuit so closely. When such a system of 

 circuits is in oscillation, it has been found possible not only to receive 

 continuous waves by means of the l)eat method, but also very greatly to 

 amplify them as well. 



The phenomena involved may best be understood by reference to Figs. 

 23 and 24, which show the relation between wing current and time at the 



