Patent GB-679993-A (GB)
Title: Improvements in or relating to electronic calculating or accounting apparatus
IPC: G06F7/505
Filed: 1950-06-16
Abstract: 679,993. Digital electric calculating-apparatus; statistical apparatus. COMPAGNIE DES MACHINES BULL. June 16, 1950 [July 7, 1949], No. 15167/50. Class 106 (i). Electronic calculating-apparatus includes a binary accumulator having, for each denomination, a pair of connected trigger circuits, one of which forms the registering means and the other of which serves to store transfer pulses. Trigger circuits. The trigger circuits are of two forms A and B, each of which comprises a double triode hard valve connected so as to have two stable states. The form B, Fig. 1a, has an input terminal E connected to both grids, an output terminal S2, and an additional input terminal F associated with crystal diode rectifiers 33, 34 and 35 so that negative impulses applied thereto are passed to one of the grids only to switch the trigger, if it is registering, to its non-registering state. The form A is similar but has no additional terminal F. Both forms include a neon lamp N to indicate when the trigger is in its registering state. Memory device. One or more memory devices 40, Fig. 4a, each comprise, for each denomination, a trigger circuit of form A having its output terminal S2 connected by a lead 44 to the screen grid of a pentode 70 forming a gate circuit. When a negative pulse is received through a lead 43 at the input terminal E of the trigger circuit in its non-registering state (Fig. 1a), the trigger assumes its registering state and the output terminal is at high potential. Thereafter, a positive read-out impulse applied through a lead 67 to the control grid of the pentode 70 will give rise to a negative pulse at the anode which is connected to a lead 46. Accumulator. Each denomination of the accumulator 41, Fig. 4a, comprises a trigger of form A and a trigger of form B, having its input terminal E connected to the output terminal S2 of the trigger A, and having its output terminal connected to the input terminal of the trigger A of the next higher denomination. Transfer means. When a trigger of form A passes from its registering state to its non- registering state (Fig. 1a), the drop in the potential of the output terminal S2 switches the associated trigger B to its registering state to store a transfer unit. After an addition operation in the accumulator, a series of positive pulses is applied to a lead 49, Fig. 4a. The pulses are inverted by a valve 71 and applied as negative pulses to the additional terminals F of all of the triggers B, along leads 48. The first pulse will restore any registering triggers B and, as each is restored, the drop in potential at its output terminal S2 is applied to the input terminal of the trigger A of the next higher denomination, to effect the transfer. If this should produce a consequential transfer, the corresponding trigger B will be operated and will be restored by the following pulse of the series and so on. The series contains a number of pulses at least equal to the number of denominations less one. Data-entering; Addition. Two numbers to be added are represented in binary form by punched holes in the same row of a recordcard 72. The numbers are sensed by electric contact through the holes, the sensing brushes for one term being connected to the input leads 43 of the several denominations of the memory device 40 and those for the other term being connected by leads 45 to the input terminals of the triggers A of the several denominations of the accumulator. The two terms are thus entered simultaneously in the memory device and accumulator respectively. A commutator brush 64 connected to a positivepulse generator 69 then engages a segment 66 to apply a single positive pulse to the lead 67 for the gate circuits 70 to enter the number stored in the memory device into the accumulator to be added to the number previously entered. The commutator brush then engages a segment 68 to apply the series of transfercontrol pulses to the lead 49. As the commutator brush completes its cycle, an eccentric pin 62 on the commutator shaft advances by one step a notched wheel 61 fast to the recordcard feed roller 60 so that the next row of the card is sensed.