Patent GB-712229-A (GB)
Title: Improvements in or relating to electronic counting and/or selecting arrangements
IPC: H01J17/48
Filed: 1949-11-29
Abstract: 712,229. Electronic counting-apparatus. ERICSSON TELEPHONES, Ltd., and ACTON, J. R. Nov. 29, 1950 [Nov. 29, 1949], No. 9810/53. Divided out of 712,174, [Group XL(a)]. Class 106 (1). [Also in Group XL(c)1 A counting circuit comprises a co'd cathode gas-filled discharge tube MT, as described in Specification 712,174, [Group XL(a)], having four electrode assembly units W, X, Y and Z, of the type described in Specification 712,171. Each unit has an anode A, connected through a resistor R35, R36, R37 or R38 to a positive potential at P12, and first and second guide cathodes G1 and G2 having a plurality of electrodes connected together and to the corresponding electrodes in the other units. Unit W has three signal/transit electrodes WS1-3, led separately out of the tube and connected to the arm of a switch SW. Units X, Y and Z have four, five and seven signal/transit electrodes respectively, connected to the arms of switches SX, SY and SZ. The circuit is adapted to select a pre-determined combination of signal/transit electrodes, comprising one electrode from each unit. by means of the coincidental investment of each said electrode by a glow discharge, and to give an output pulse when each such selection occurs. With each switch in the off position signal/transit electrodes WS3, XS4, YS5 and ZS7 are connected through contacts STA1, STA2, STB1 and STB2 respectively to zero potential at 0, and a glow discharge invests each said signal / transit electrode. Negative potential at N11 is extended by way of resistors R31-34 to diodes RAW-Z, current flows through each diode from lead P11 which is connected to a positive potential and lead OP is maintained at a negative potential owing to the voltage drop in resistor R41. The pre-determined combination of signal/ transit electrodes is obtained by setting the arms of the switches into contact positions corresponding to the electrodes in the said combination. If, for example, it is desired that the combination shall be selected on the receipt of 29 pulses, the switches SW, SX, SY and SZ are set on contacts 2, 1, 4 and 1 respectively. The selected electrodes are extended to negative potential at N11 by way of resistors R31-34 and to the cathodes k of the diodes RAW-Z. The signal/transit cathode not included in the combination are returned to zero potential at 0. Start key KST1 is operated and high-speed relays STA and STB, connected to a negative-potential at N12, operate to open contacts STA1, STA2, STB1 and STB2 and break the connections from cathodes WS3, XS4, YS5 and ZS7 to zero potential at 0 but each cathode is still connected to 0 by way of its associated switch arm. Lines L1 and L2 are connected to an alternating current source so that pulses from the secondary winding S of transformer TRB are applied to the first guide cathodes G1 and in delayed phase, owing to the presence of capacitor C32 and resistors R39 and R40, to the second guide cathodes G2. The glow discharge steps around each unit, but provided the selected signal/transit cathodes are not invested concurrently, one or more of the diodes RAW-Z will conduct, and lead OP will be maintained at a negative potential. When the selected cathodes are invested concurrently, positive potential from P12 is extended to the cathodes of all the diodes, which are rendered non- conductive, and the positive potential at P11 is extended to lead OP to give an output pulse. A modified circuit (see Group XL(c)) comprises a tube having three units in which the glow discharge completes a cycle on the receipt of nine, ten and eleven pulses respectively. Only one signal/transit electrode of each unit is led directly out of the tube, the remainder being connected together and to the corresponding electrodes in the other units. The circuit is adapted to divide in the scale of 990, but by covering the top of the tube with a screen which is perforated and marked in positions corresponding to the signal/transit and/or transit cathodes, the positions of the glow discharges at any instant may be observed and the number of pulses that the tube has received may then be calculated. As an alternative, in either of the above arrangements, some or all of the electrode assembly units may be contained in separate glass envelopes.