ELECTRIC CIRCUIT THEORY 89 



Computation and analysis of these formulas involve an elementary 

 knowledge of Bessel functions. The properties necessary for our 

 purposes are briefly discussed in an appendix to this chapter. 



The indicial admittances for the non-dissipative low-pass filter, 



05 



°0 2 4 6 8 10 12 14 16 16 20 22 24 26 28 30 32 54 36 38 40 

 Values of to^t 



p;g_ 20— Low pass wave filter. Indicial admittance of initial section (m = 0). 

 Multiply ordinates by VC/L 



Values of Wrt 



pig_ 21— Low pass wave filter. Indicial admittance of third section (n = 2). 

 Multiply ordinates by VC/L 



2 4 



Values of u).t 



Fig. 22— Low pass wave filter. Indicial admittance of fifth section («=4). 

 Multiply ordinates by VC/L 



that is, the current in response to a steady unit e.m.f. applied at 

 time / = 0, are shown in the curves of Figs. 20, 21 and 22, for the 

 initial or zeroth, the 3rd and the 5th sections, respectively. These 

 curves together with the exact and approximate formulas given 



