Patent GB-675607-A (GB)
Title: Improvements in or relating to electronic accumulators
IPC: G06F7/498
Filed: 1950-01-16
Abstract: 675,607. Digital electric calculating - apparatus. REMINGTON RAND, Inc. Jan. 16, 1950 [March 25, 1949], No. 1134/50. Class 106 (i). In a carry device for an electronic accumulator comprising a trigger stage connected between each adjacent pair of denominational orders which is actuated when the capacity of the lower order is exceeded and restored by a pulse from a generator to effect an entry of one into the higher order, the generator supplies a series of timed restoring pulses to each trigger stage an interval of time after the initial registration of digit values has finished. The amount to be added into accumulator is set up on a multi-bank keyboard 10, Fig. 1. A start signal is then applied over a line 25 to a pulse generator and control unit 17 and appropriate pulses are passed by the operated keyboard switches to the several denominational orders 11, 12 and 13 of the accumulator over lines 14, 15, 14a, 15a and 14b, 15b. The pulse generator and individual orders of the accumulator, which are of codeddecimal form, are as described in Specification 665,714. Adjacent orders are connected by trigger carry stages 18, 19. As an order passes from a registration of 9 to a registration of 0, the corresponding trigger carry stage is operated. When the direct entry into the various orders has been completed, a carry pulse generator 22 sends a series of pulses simultaneously to the several carry stages. The first pulse restores any operated carry stages, each of which, on being restored, sends a pulse to the next higher order to add one therein. Consequential carries are effected by successive pulses from the generator 22. When all of the carry stages are unoperated, the carry pulse generator ceases to operate. Each carry stage, e.g. 18, Fig. 4, comprises a double-triode 37 forming part of a stable trigger circuit and normally conducting in its left-hand section. When the lower order passes from 9 to 0, a negative pulse, received on a lead 23, switches the trigger and so increases the potential of the left-hand anode connected by a lead 21 to a neon light 40, Fig. 2, forming part of the carry impulse generator. The neon light 40 fires and the potential of the right-hand grid of a doubletriode trigger 41 is raised to switch the valve from its normal state, in which the left-hand section is conducting. The consequent rise in the potential of the left-hand anode is passed by a lead 42 to the right-hand grid of a doubletriode gate 43 to prime that half of the valve. When the direct entries have been completed, the control unit applies, in a manner not described, a negative pulse to a lead 26. The pulse is delayed and inverted by an unbalanced double-triode trigger 44 and then applied by a lead 45 to the grids of the gate valve 43. The primed right-hand section is thus caused to conduct and the consequent drop in its anode potential is applied by a lead 46 to the lefthand grid of a double-triode stable trigger 47 which is thereby switched from its normal condition to conduct in its right-hand section. The consequent rise in the right-hand anode potential is passed by a lead 48 to a multivibrator circuit including a double-triode 50. The multivibrator is thus caused to oscillate and applies pulses via leads 51, 52 to the grid of an inverter triode 38 which produces negative pulses on a lead 20 connected to all of the carry stages. The receipt of such a pulse by a carry stage, Fig. 4, restores the trigger 37 to its normal state of conduction in the left-hand section. The right-hand anode is capacitycoupled by a lead 24 to the next higher order so that a positive entry pulse is applied thereto. Consequential carries are then effected during successive cycles of the multivibrator. The lead 21 of each carry stage is connected to a neon light 40 so that, only when no carry stage is in the operated state, does the trigger 41 resume its normal stage. When this occurs, the potential of the lead 42 is lowered to render the right-hand section of the gate 43 non-conducting and the potential of a lead 55 connected to the right-hand anode of the trigger 41 is raised to prime the left-hand sections of the gate 43 and of a further double-triode gate 54. The next pulse produced by the multivibrator and applied by leads 51 and 53 to the gate 54 will then render the left-hand section of the gate 54 conducting. The corresponding anode is capacity-coupled to the trigger 47 by a lead 57 and so restores it to its normal condition, whereupon the rise in its right-hand anode potential, through lead 58, a condenser and the right-hand side of the valve 54, produces a negative pulse on leads 60 and 27 which signals to the control unit that the operation has been completed. If no carry is required, the start signal pulse on the line 45 produces a pulse on the line 27 via the left-hand section of the gate 43 which is primed as described.