Patent GB-741985-A (GB)
Title: Improvements in or relating to a circuit arrangement including a gaseous discharge tube of the glow transfer type
IPC: H03K29/00
Filed: 1951-08-14
Abstract: 741,985. Multi-gap cold-cathode tubes. INTERNATIONAL BUSINESS MACHINES CORPORATION. Aug. 14, 1951 [Aug. 23, 1950], No. 19116/51. Class 39 (1). [Also in Group XIX] A cold-cathode gas-filled counting tube comprises two cathodes and two anodes, each having a number of commonly energizable elements. In one arrangement, Figs. 2 and 3, an upper cathode structure UC comprises ten fingers UC0 to UC9 secured equidistantly around the circumference of an annular ring 10 by means such as welding. A lower cathode structure LC comprises nine fingers 1p to 9p secured to a ring 11. The cathode structures are mounted so that the fingers of each extend through each of two insulating discs 12 and 13. The upper cathode structure UC is energized through a lead wire 14UC welded to the ring 10, extending through holes in the discs 12 and 13 and terminating on a pin (not shown) in the tube base. The lower cathode structure LC is energized through a lead wire (not shown) welded to the ring 11 and terminating on a pin in the tube base. A starting electrode OS terminates on a pin in the tube base and extends through holes in the discs 12 and 13 so that it is positioned in alignment with the fingers of the lower cathode structure LC. An upper anode structure UA comprises a ring 20 and ten fingers UA0 to UA9 energized through a lead wire 22UA and a lower anode structure LA comprises a ring 21 and ten fingers LAO to LA9 energized through a lead wire 23LA, the anode structures being of less diameter than the cathode structures. The electrode structures and lead wires external to the generally cylindrical structure between the discs 12 and 13 are coated with insulating material to confine the glow discharge to the region between the discs 12 and 13. The tube is connected in a circuit arrangement (see Group XIX) comprising a multivibrator and two trigger circuits whereby high and low positive voltages are applied alternately to the upper and lower anodes UA and LA, the lower cathode LC is connected through a switch to earth, the starting electrode OS is connected through a resistor to earth and negative-going pulses are applied through a switch to the upper cathode UC. With both switches open a discharge is established between OS and LA0 (Fig. 3). The switches are then closed and, in response to the changing voltages on the electrodes, the discharge is transferred to exist between LAO and UC0, UC0 and UA0, UAO and 1p and finally between 1p and LA1, indicating the receipt of one input pulse. The cycle is repeated continuously until the switch passing the negative-going pulses to the upper cathode UC is opened. An output pulse is generated each time the discharge exists between OS and LAO. In an alternative arrangement, Figs. 5 and 7, the anode structure A1 comprises ten fingers A1-0 to A1-9 secured around the circumference of a ring 65 connected to a lead wire A1-70 secured to a pin 69 in the base (not shown) of the tube. The anode structure A2 comprises ten fingers A2-0 to A2-9 secured around a ring 66 of greater diameter than the ring 65, the fingers of the anode A1 sloping outwards from the ring 65 and then extending parallel with the fingers of the anode A2 which is connected to a lead wire A2-72 secured to a pin 71. The fingers of the anodes extend through insulating discs 67 and 68. The cathode elements and starting electrode are each in the form of a rectangular metal strip, having spikes extending from three corners thereof and a small hole extending through the centre. Cathode C1 comprises ten elements C1-0 to C1-9 mounted between the discs 67 and 68, two spikes of each element extending through the upper disc 67 and one spike extending through the lower disc 68 for connection to a commoning ring 76 which is connected by a lead wire C1-76 to a pin 77. Cathode C2 comprises wire elements 1p to 9p each having a spike at the opposite lower corner to the spike on the elements of cathode C1 and extending through the disc 68 for connection to a commoning ring (not shown) which is of smaller diameter than ring 76 and is connected by a lead wire C2-81 to a pin 82. A starting cathode OS similar to the elements of cathode C2 is connected by a lead wire OS-80 to a pin 78. The tube is connected in the circuit mentioned above and a discharge initially established between OS and A1-0 (Fig. 7) is transferred to exist between A1-0 and C1-0, C1-0 and A2-0, A2-0 and 1p, and finally between 1p and A1-1 to indicate the receipt of one pulse. A similar transfer takes place in response to each subsequent pulse. The construction of the cathodes as strips results in a restriction of the migration of ions and the hole extending through each cathode permits ionization of a predetermined region within the tube to ensure the correct transfer of the glow discharge. In either arrangement the discharge can be stepped in either direction around the electrode structure by suitable application of the voltages so the tube can be used for addition and subtraction.