Physics. — ''On the use of the aud'ion in iv'ireles.'^ teldi^r(iph)/\ By 

 I). CosTKR. (Communicated by Prof. H. A. Lohkntz). 



(Communicated in the meeting of March 29 1919). 



In the recent successes in wireless telegraplij the three-electrode- 

 i-elais or audion has played the most important part. Tiie audion 

 consists of a vacuum tube, in wliich are fused three electrodes: a 

 hot vvire-katiiode /, a usually tiat anode <i and a third auxiliary 

 electrode h, placed between ihe other two and consisting- of a few 

 parallel and mutually connected metal wires, which is therefore 

 called the grid. The properties of the audion ai-e determined by the 

 audion-characteristics, which gi\e the i-elation of the currents /V( and 

 //, on the one side and the potentials e and /• on the other. (See 

 fig. J). The current //, is usually veiy small compared to /„ and it 

 mav be neglected in many cases. A simple scheme for the detei-mi- 

 nation of the characteristics is given by fig. J, where for the sake 

 of simplicitv the measuring instruments are not indicated, Kig. 2 

 gives /„ as a function of' e. for different values of r. The different 

 characteristics may be deduced from one au(»ther by parallel tran.s- 

 latiou. Fig. 3 gives /„ as a function of v, while e is a constant. 



Fig. 1 



