GB436420A - Improvements in or relating to electrical circuits employing gaseous discharge tubes - Google Patents

Abstract

436,420. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd., 63, Aldwych, London.-(Assignees of Vereinigte Telephon-und Telegraphenfabriks Akt.-Ges. Czeija, Nissl, & Co. ; 75, Dresdnerstrasse, Vienna) Nov. 30, 1934, No. 34404. Convention date, July 30. [Class 40 (iv)] [See also Groups XXXV, XXXVIII, and XL] A chain of gaseous discharge tubes such as neon lamps is employed to receive impulses. The principle employed is shown in Fig. 1b, in which a current impulse through the transformer Tr1 aiding the battery B1 causes the neon lamp L to glow. A reverse impulse then reduces the potential sufficiently to extinguish L1, and the cessation of current induces an impulse in the transformer Tr2 which causes the lamp L2 to glow. Fig. 2 shows a chain of neon lamps L1-6 controlled in this manner by a reversing contact K, one lamp lighting at each reversal. The current in the last lamp lighted may control connecting or storage relays. Such an arrangement may be employed for transforming the frequency of an applied alternating current. For example, a complete operation of the chain of 6 lamps is effected by 3 impulses, so that an input frequency of 600 say operating the contact K in synchronism would give rise to an output frequency of 200 in the transformer Tr7. Fig. 3 shows a number indicator board comprising a chain of lamps L1-6 controlled by dialled impulses. An impulse through the transformer Tr7 due to the change over of a key K lights the lamp L1 by means of its control electrode E1. The first dialled impulse extinguishes L1 and L2 lights due to an induced impulse through the transformer Tr1. Subsequent impulses light the remaining lamps in turn in a similar manner.