GB681882A - Electronic apparatus responsive to electrical impulses - Google Patents

Abstract

681,882. Digital electric calculating-apparatus. NATIONAL CASH REGISTER CO. March 5, 1951 [May 25, 1950 ; May 25, 1950], No. 5227/51. Class 106 (i). [Also in Group XL (c)] Apparatus for counting electrical impulses comprises electron tubes which are rendered conducting seriatim in response to impulses, in which corresponding electrodes of the tubes are interconnected so that the impulses are applied in common to these electrodes in order that, when a tube is initially rendered conducting, the variation of potential at its said electrode is transmitted to the interconnected electrodes of the other tubes to cause any conducting tubes to be rendered non-conducting, and so that the potential at said electrode, on stabilization of the circuit after the impulse, is applied to the tube next in sequence to prime that tube so that it will be rendered conducting in response to the next impulse. Each order of an accumulator comprises ten digit-representing tubes, an entry tube E and a transfer tube T, all of which are gas-filled tetrodes. The control electrode of each digit-representing tube is negatively biased but also connected to the cathode of the preceding tube so that when one tube is conducting, the next is primed. Positive input pulses on a lead 59, applied to the control electrode of the tube E, which is self-extinguishing, produce negative pulses at the anode, which is connected to a common lead 47, resistance-capacity coupled to the cathodes of all the digit-representing tubes. Each such pulse, by lowering the cathode potentials, fires the primed tube. The consequent rise in the cathode potential of the fired tube produces a positive pulse at each of the other cathodes which is sufficient to extinguish the previously conducting tube. When the " 9 " tube is conducting, both the " 0 " tube and the transfer tube T are primed. The next positive pulse fires the " 0 " tube as previously described, and is directly applied to the control electrode of the tube T so as to fire this tube, which is self-extinguishing, and to produce a positive pulse at its cathode which is connected by a lead 78 to the tens input lead 65. The closing of a switch 60 in each order removes the negative bias on the control electrode of the " 0 " tube to render it conducting.