288 



BELL SYSTEM TECHNICAL JOURNAL 



10 



.5 



H(i) 



.2 



.1 



.05 



.02 

 .01 



10 



20 



50 



100 200 



i - Klloamperes 



Figure 10 — Function Hiyi) when Po(0 is approximated by: 



Po{i) = exp(— /fei), k = .038 per kiloarapere. 



H{i) = k-^'limh-"' + ix^ erfc(^z-)^] 



From Fig. 1, it is seen that Po(0, as represented by curve 1, is nearly a 

 straight Une on semi-log paper and may, therefore, be approximated by: 



Po(0 ^ e-'' (97) 



With k = .038 per kiloampere, a straight line is obtained which coincides 

 with curve 1 at ? = and i = 100 kiloamperes, and this value of k has been 

 used in the following. The functions H and G obtained with this approxi- 

 mation are shown in Figs. 10 and 11. In obtaining these integrals, the up- 



