THERMIONIC VACUUM TUBES 



39 



the American Telephone and Telegraph Company is using a six 

 phase rectifier giving about 200 kw. at about 10,000 volts. 13 



6. Two-Electrode Tube as Rectifier. Three typical forms of circuit 

 are shown in Figs. 6, 7, S, each of which has certain characteristics 

 not possessed by the others. The circuit shown in Fig. 6 rectifies 

 the full transformer voltage, but utilizes only one-half of the current 

 wave; the circuit of Fig. 7 gives a d.c. voltage of only about half the 

 transformer peak voltage but utilizes both halves of the wave, and 

 Fig. 8 illustrates a circuit making use of the full transformer voltage 

 and both halves of the a.c. wave. 



A rectifier circuit employing a tuning condenser for the secondary 

 of the high voltage transformer and giving a rectified d.c. voltage as 

 large again as the a.c. voltage of the transformer and providing auto- 

 matic control of the maximum d.c. voltage supplied by the rectifier, 

 has been described by Webster. 14 



T 



X 



Ci 



L1 



X 



I 



L2 



Load 



12 



Fig. 7 



IV) 

 Fig. S 



X 



The circuits shown in Figs. 6 and 7 provide means in the form of 

 condensers G, C 2 and inductances L\, L> for smoothing out the rectified 

 voltage. Such an arrangement of conductors is essentially a network 

 whose attenuation for electric currents of a certain range of frequencies 

 is very low and for all other frequencies is high. This type ot network 

 is a special form of the electric ivave-filter which is finding main' ap- 



11 Arnold and Espenschied, Journal of A, I. E. E., August, 192 ^ : also Bell System 

 Technical Journal, October, 1023. 



u D. L. Webster, Procd. Xat. Acad., Vol. 6, p. 28, p. 269, 1920. These art irks 

 also suggest certain modifications of Hull's method. 



