GB708424A - Improvements in or relating to cold cathode gaseous discharge devices - Google Patents

Abstract

708,424. Electronic counting apparatus. WESTERN ELECTRIC CO., Inc. June 23, 1950 [June 25, 1949; Aug. 9, 1949; Aug. 9, 1949], No. 15736/50. Class 106 (1). [Also in Groups XXXIX and XL(a)] In a counting circuit comprising a cold cathode discharge tube (see Group XL(a)), directional transfer of the discharge is obtained by using specially shaped cathodes, as shown in the explanatory Fig. 6. The channel-shaped portion of a cathode is more efficient as a glow discharge element than the plane tail portion. Consequently the discharge between ray cathode AO and the anode 38 will concentrate at the channel portion of this cathode, and the tail portion of cathode B' will extend into a region of high ionization density whereas cathode BO is located in a region of low ionization density, so that the discharge will have a preference to transfer to B' rather than to BO. Consequently, if a pulse, indicated at P, is applied to the cathodes BO and B', the discharge will transfer initially from the cathode AO to the cathode B' and will concentrate at the channel portion of the cathode B'. At the cessation of the pulse, the discharge will transfer to the cathode A' and will concentrate at the channel portion thereof. The counting circuit shown comprises a discharge tube having A cathodes 56 numbered 1 to 10 and adjacent auxiliary cathodes 58 inter-connected on a twoout-of-five basis by five arcuate conductors 66 connected to output terminals O, I, II, IV and VII, and thence to load resistors 750, 75I, 75II, 75IV and 75VII. The ten B cathodes 57 are connected by way of a metallic ring 65 to a pulse source 81 and an index or reset cathode 69 is connected to a pulse source 79. The anode 71 is connected to a source of positive potential through resistors 76 and 77, of which the latter may be short-circuited by a switch 78, the potential applied to the anode being below the breakdown potential of the anode-cathode gaps, but somewhat greater than the sustaining potential for these gaps. In the operation of the device, a pulse is applied to the index or reset cathode 69 to initiate a discharge at this cathode. The discharge is then transferred from the reset cathode 69 to any desired one of the A cathodes by applying the proper number of pulses from the source 81 to the B cathodes. When the discharge is stepped to any of the A cathodes, because of the current flowing through the anode resistors 76, 77 and the associated one of the output resistors 75, that cathode becomes positive with respect to the auxiliary load cathode 58 adjacent thereto and as a result, at least a portion of the discharge shifts to such adjacent auxiliary cathode, and voltages appear at the output resistor associated with the A cathode and also at the output resistor associated with the auxiliary load cathode adjacent that A cathode. For example, if the discharge is stepped to the A cathode at position 6, voltages will appear at the output resistors 75 II and 75IV. When the discharge is stepped to any A cathode, the switch 78 may be closed to increase the discharge current and ensure a discharge between the anode and both of the cathodes corresponding to the position to which the discharge has been stepped. The five resistors 75 may have associated therewith ten output or load circuits coupled to the resistors in such manner that each circuit will be energized when a respective ipair of resistors has voltages produced thereacross. Thus, each load circuit will correspond to a respective one of the A cathodes and may be completed by applying the proper number of pulses from the source 81 to the B cathodes 57. The discharge may be returned from any A cathode to the index or reset cathode 69 by application of a large negative pulse from the source 79 to the cathode 69. An alternative embodiment comprises a tube in which the auxiliary cathodes are omitted. Input pulses are applied to the B cathodes through a switch which at the end of a prescribed period is thrown to a second position and stepping pulses are applied from a reading device to the B cathodes until the discharge is returned to an index or reset cathode, whereupon a positive output pulse is supplied to the reading device. The number of pulses supplied through the switch in its second position is counted and the difference between this number and the number of positions in the device indicates the number of pulses applied through the switch while it was in its first position. The arrangement may also be used as a frequency divider.