184 THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1957 



is passing current. The barium regenerative process seems therefore to 

 be electrolytic in nature and, depending only on current flow and a stock 

 of oxide, would appear to be virtually inexhaustible. 



These few remarks are perhaps sufficient to give some idea of the lines 

 on which the British research effort has run during the past decade. More 

 detailed descriptions have ah-eady been presented elsewhere.^- s. e, 7 



Electrical and Mechanical Characteristics 

 Electrical Characteristics 



The main electrical characteristics of the 6P12 are shown in Figs. 11 

 and 12. The heater voltage used for both sets of curves is 5.5 volts, the 

 same value as that used in the British amplifier. 



Fig. 11 shows the change of transconductance with anode current, 

 with screen voltage as parameter. An anode voltage of 40 volts and a 

 suppressor voltage of zero correspond with the static operating condi- 

 tions in the first two stages of both the Aberdeen-Bergen and the British 



7.2 



6.8 



O 

 > 



cr 6.4 

 ai 



Q. 



in 

 111 

 tr 6.0 



LU 

 CL 



< 



_l 5.6 



~ 5.2 



m 



o 



z 



< 



U 4.8 



3 

 Q 



Z 



o 



o 

 in 

 z 

 < 



tr 



4.4 



4.0 



3.6 



2 3 4 5 6 7 



ANODE CURRENT IN MILLIAMPERES 



Fig. 11 — Typical transconductance-anocle current characteristics for a type 

 r)ri2 tvihe (No. 457/6). 



