502 



BELL SYSTEM TECHNICAL JOURNAL 



ANODE 

 ■////////////////////// //////////////////////////////. 



ANODE 



V///////// /////////////////////. 



OXIDE COATING 



OXIDE COATING 



V77777777777777777777777777777777777777777777777777? 



CATHODE METAL 

 CURRENT MICROWAVE TRIODE 



V777777777777777777777777777777, 



CATHODE METAL 



B.T.L.-1553 TRIODE 



Fig. 2. — Comparison of the spacings of the 1553 triode at the right with a previously 

 existing microwave triode at the left. 



GRID FRAME 

 GRID SPACER 



ANODE 



"^^^ OXIDE 

 STEATITE 

 BACKING ROD 



MOLYBDENUM 

 SUPPORT LEG 



NICKEL 

 CATHODE PLUG 



RIVET HOLE 



STEATITE CATHODE 

 SUPPORT RING 



Fig. 3, Perspective drawing of the active elements of the 1553 close-spaced triode. 



