JOURNAL 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. VI FEBRUARY 19, 1916 No. 4 



ELECTRICITY. — Quantitative experiments with the auction. 

 L. W. Austin, U. S. Naval Radiotelegraphic Laboratory. 



The extent to which vacuum tube detectors of electrical waves 

 have come into general use both for damped and undamped 

 oscillations has made it desirable to determine the law of response 

 of these instruments, especially as they are often used with 

 shunted telephones for making estimates of the strength of 

 received signals in radiotelegraphy. 



The form of vacuum detector chosen for investigation was the 

 DeForest three-electrode audion. 1 



As is well known the audion can be used either as. an ordinary 

 detector (old audion connection) with the secondary receiving 

 circuit connected to the hot filament and the intermediate 

 electrode (grid), or by connecting to the grid and cold plate 

 (ultraudion connection) local oscillations may be set up in the 

 receiver so that signals may be received by the beat method. 



For determining the laws relating to the strength of the received 

 waves and the response of the detectors, the circuit containing 

 the audion was excited by a wave meter in which oscillations of 

 varying strength were produced either by an oscillating audion 

 for undamped or by a buzzer for damped excitation. 



As it is impossible to use a galvanometer directly in the tele- 

 phone circuit of the audion on account of the continuous current 

 flowing through it from the dry battery, the following arrange- 



1 For description, see Bulletin Bureau of Standards, 6: 540. B,eprint 140, 

 1911. 



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