GB707458A - Improvements in or relating to multi-electrode gaseous-discharge tube circuits - Google Patents

Abstract

707,458. Digital electric calculating apparatus. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Feb. 20, 1952 [Feb. 24, 1951 ; June 11, 1951], Nos. 4530/51 and 13748/51. Class 106 (1) A carry circuit comprises first and second multi cathode gas-discharge tubes, means for applying a pulse train to the first tube to step the discharge, means for generating an output pulse when the discharge reaches the output electrode of the tube, a gate circuit operated by the output pulse to pass a carry pulse, generated after the termination of the pulse train, to move the discharge in the second tube, and means for restoring the gate circuit. Multi-cathode tubes 34, 33 form the units and tens denominations of a totalizer into which entries are made from a similar pair of tubes 32, 31, as described in Specification 699,696. The ten pulse pairs necessary for performing this operation are provided by a pulse generator 46, and if during this period, the discharge in tube 34 appears on the zero output cathode 39, a pulse is delivered to fire a cold-cathode discharge tube 40, thus registering the fact that a carry must be made to the tens denomination. A double triode 41, normally L.H. side conducting, is made R.H. side conducting by rise in potential at the cathode of tube 40, and when a pulse is delivered at the cathode of valve 41 by the generator 46 at the "carry" time in the cycle it causes a drop at the anode 43 which delivers a pulse to the "tens" multicathode tube 33, and also extinguishes the tube 40: this, in turn, causes lowering of the voltage on the R.H. grid of tube 41 thus returning the tube to the L.H. side conducting state and returning a "finish" signal to the generator on line 45. A circuit 38, similar to the circuit 37, may be arranged to transfer a unit (" fugitive one ") from the highest to the lowest denomination during subtraction by complementary addition. An alternative arrangement of the circuit 37 in which the tube 40 is extinguished by a separate pulse in its anode circuit, is also disclosed.