290 



THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1952 



contact. Algebraic equivalence of this circuit with the original is shown 

 below. 



/(.4) = (L'A + B'){L + A) (Fig. 2c) 



= {U + B'){A + B'){L + A) (3b) 



= (L' + B'){L + A) (12a) 



KB) = (L'A + S)(L + .4) (Fig. 2c) 



= (U + B)(A + B){L + A) (3b) 



= (U + B){L + .4) (12a) 



For the C relay which operates and releases twice in the entire 32 

 combination cycle 



g{C) = (.4' + 5 + £>' + E')(A' + B + D + E) 



r(C) = [(A + 5' + L> + E')iA + B' + D' + E)] 



h{C) = [(A + 5' + /) + E'){A + 5' + £>' + E)]' 



= (A'BD'E + A'BDE') (7a, 7b) 



and 



/(C) = [(.4' + 5 + £»' + ^OC^-i' + 5 + L> + j^)] 



[C + A'BD'E + A'5Z)£'] 



= [A' + B + (Z)' + ^')(£> + £")] 



[C + A'B{D' + 7?')(/) + E)] (3a, 3b, 13) 



= [.4' + 5 + (i)' + ^')(^ + ^^)][^' + ^^'B] 



[C + (/)' + E'){D + £")] (3b) 



= [{A' + 5)C + {D' + £')(/>> + i^)]K' + -i'5] (3b) 



The schematic circuit which the above represents is shown in Fig. 3a. 



Circuits of this type which use certain contacts more than once can some- 



■i ^ 1 ) 



^ .V 1 db 



-X — X- 



L B 

 -X- 



(a) 



: — -v 1 



L 



-X X- 



(b) 



'b_ 



(A) 



ADDED TO COVER 

 TRANSFER TIME OF 

 (L) RELAY CONTACTS 



(B) 

 ■5VFR (- J 



I'Hl 



HllhL 



(c) 



Fig. 2 — Pulse divider of counting circuit. 



