ELECTRIC CIRCUIT THEORY 



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between terminals 22 by 5oi(/) =52i. 5ii is the driving point indicial 

 admittance with respect to terminals 1 1 and ^21 the transfer indicial ad- 

 mittance of terminals 22 with respect to 11 under short circuit con- 

 ditions. 



Similarly if terminals 11 are shortcircuited and a unit e.m.f. inserted 



Fig. 27 



between terminals 22 the current flowing between terminals 22 is 

 denoted by 522(0 =-^22 and that flowing between terminals 11 by 5i2(/) 

 =-Sii. If the network is passive, i.e., contains no internal source of 

 energy, it follows from the reciprocal theorem that 821 = Sio. As far 

 as the two sets of terminals are concerned, the network is completely 

 specified by the indicial admittances 6'ii,522,'S'2i = 5'i2. 



Now let a voltage Wit) = Vi be inserted between terminals 11, and 

 a voltage Vi{t) = Vi between terminals 22. The current flowing 

 between terminals 11, denoted by Ji is 



h{t)=jJv,{r)S,,{t-r)dr+jJWr)S,2{t-r)dr (253) 



while the corresponding current between terminals 22 is 



h{t) =jJv,{r)S,,{t-T)dr+jJWr)S,,{t-r)dT (254) 



Now consider two networks of indicial admittances 5ii, ^22, 512 = 521 

 and Tn,T22,Tn=T2i respectively and let them be connected in tandem 

 as shown in Fig. 28 to form a compound network. 



Fig. 28 



We require the indicial admittances of the compound network in 

 terms of the indicial admittances of the component networks. 



Short circuit terminals 22 of the compound network and insert a 



