GB658370A - Electronic impulse counting circuits - Google Patents

Abstract

658,370. Counting-apparatus. NATIONAL CASH REGISTER CO. Aug. 5, 1949, No. 20375. Convention date, Dec. 15, 1948. [Class 106 (i)] [Also in Group XL (c)] A counting circuit comprises a series of gasfilled discharge tubes connected in a chain or closed ring which are fired sequentially by pulses applied to all of the tubes, each of the tubes having a main and an auxiliary control electrode both of which are normally biassed to prevent the tube from conducting and in which a tube is rendered conducting by the reduction of the bias on both control electrodes occurring at the same time as an applied input pulse. The Figure shows a series of gasfilled tubes 0 ... 9 connected in a closed ring. The anodes of all the tubes are fed through a common resistor 29 so that when one valve is rendered conducting the drop in voltage across this resistor extinguishes all the remaining tubes as described in Specification 592.793. Positive going input pulses to be counted are applied at terminal 40 to the auxiliary control grids 23 of all the tubes in common-but this alone is insufficient to fire a tube until the bias on the main control grid 22 is reduced by the firing of the preceding tube in the chain and the consequent rise in its cathode potential. The chain is reverted to normal with tube 0 only conducting by operation of the zero reset switch 38.