Patent GB-756443-A (GB)
Title: Improvements in or relating to electrical pulse counting circuits
IPC: H03K23/82
Filed: 1953-08-26
Abstract: 756,443. Electrical counting-apparatus. GENERAL ELECTRIC CO., Ltd., and BEESLEY, J. H. Aug. 26, 1954 [Aug. 26, 1953], No. 23593/53. Class 106 (1). In an electrical pulsecounting circuit, each pulse operates one or more of a first group of gas-discharge tubes and thereafter operates one or more of a second group of gas-discharge tubes as determined by the operated first-group tubes, the operated second-group tubes preparing the first - group tube or tubes which is or are to operate on receipt of the next pulse. In a telephone system, a subscriber's dial actuates contact springs 53. Initially, the contacts 53 are closed and relays A and B are energized, contacts B2 and a lead 54 connecting a positive source of potential 19 to the trigger electrodes of a pair 1, 2 of a first group of coldcathode gas discharge tubes 1-5 to produce an auxiliary discharge in the tubes 1, 2. At the start of the first pulse to be counted, corresponding to the opening of contacts 53, the relay A is released and its contacts Al apply a positive potential to the anodes of the tubes 1 and 2 which is sufficient to transfer the discharges therein to the main gaps. At the same time, the potential of a lead 24 connected to a potentiometer 22, 23 rises to bias rectifiers 25, 26 so that the rise in potential of the cathodes of the tubes 1 and 2 is applied to the trigger electrodes of corresponding cold-cathode gas discharge tubes 6, 7 of a second group of such tubes 6-10. An auxiliary discharge is thus initiated in each of tubes 6, 7 which becomes a main discharge at the end of the first pulse due to the release of the relay A, the contacts A1 applying a positive potential to the anodes of all of the tubes 6-10. A potentiometer 50, 51 now raises the potential of a lead 49 to bias rectifiers 31, 32, &c., forming part of gate circuits connected to the trigger electrodes of the tubes of the first group 1-5. The cathodes of the second-group tubes 6-10 are connected respectively to further bias leads, e.g. 60, 61, associated with additional rectifiers in the gate circuits. The arrangement is such that whenever a pair of second group tubes is conducting to register the existing count, the pair of first-group tubes corresponding to the next higher digit is primed by means of the gate circuits. The auxiliary discharges in the primed tubes become main discharges when, at the outset of the next pulse, the relay A is released. Thus, at the end of the first pulse, conducting tubes 6 and 7, prime tubes 1 and 3 which on receipt of the second pulse fire to prime tubes 6 and 8. The count proceeds in this fashion up to ten, a different pair of the five second-group tubes being left conducting at the end of each pulse. The relay B is slow acting and remains energized for the duration of a pulse train. A further slow-acting relay C is energized over contacts A2, B1 at the onset of the first pulse, its rest contacts C1 initially priming the tubes 1 and 2 and its contacts C2 preventing operation of the tubes 3-5 on receipt of the first pulse. A condenser 18 maintains the main discharge in the first-group tubes, and a condenser 30 maintains the bias potential of the lead 24, long enough to ensure a proper transfer to the second-group tubes. Condensers 21, 52 similarly ensure a correct transfer from the secondto the first-group tubes. The circuit may be modified for cyclic operation.