AD.\flTTANCF.S OF PARALLEL PLANE ELECTROS TUBES 



629 



These are very similar in all respects to those of the preceding figure. Tt is 

 probable that the eathode-anode spacings of the two diodes of Figs. 6 and 10 

 were somewhat greater than the 0.65 mil for which they were designed. In 

 both cases the capacitances measured at low frequency were somewhat low. 



HEATER VOLTAGE, 

 Vh=8.2 



DIODE NO. SN 61 



"'T^^ 



20 40 60 80 100 120 140 160 180 200 



ANODE CURRENT DENSITY, Jq, IN MA/CM^ 



Fig. 9 — Variation of g/go with current density and heater voltage. 



In Fig. 11, results are shown for a third diode. In this case the susceptance 

 at a large negative bias is in almost exact agreement with the value to be 

 expected with the intended diode spacing of 0.65 mil. It is interesting to 

 observe that, with this tube, b drops a greater amount as the current in- 

 creases. Moreover, the ratio g/go is greater than that found with earlier 

 diodes. 



In Fig. 12 data are shown for a diode having a very high value of go . 

 From the standpoint of cathode activity this was the best tube that was 



