642 



BELL SYSTE.\[ TECHNICAL JOURNAL 



X103 



-3.5 -3.0 



-2.0 -1.5 -1.0 -0.5 

 GRID VOLTAGE , Vg 



Fig. 20 — Four-pole admiltances of a triodc having a parallel-wire grid. 



that y-n is much lower when this tube is biased beyond cutofif than in the pre- 

 vious case. The electromagnetic coupling is therefore much less for the 

 mesh grid. This has also been treated in the above reference.-^ With high 

 negative bias the feedback admittance yx2 was substantially equal to y-n 



