Patent GB-668824-A (GB)
Title: Electronic calculating device
IPC: H03K29/00
Filed: 1948-02-27
Abstract: 668,824. Cathode-ray tubes. RADIO CORPORATION OF AMERICA. Feb. 27, 1948 Aug. 13, 1943], No. 6128/48. Class 39 (i). [Also in Group XIX] An electronic calculating device comprises an imperforate target 10, Fig. 1, back-coupled to a deflecting electrode 18, an apertured target 11 having an aperture, two opposite edges of which are formed with sets of teeth 0, 1 ... 9 ; 0<SP>1</SP>, 1<SP>1</SP> ... 9<SP>1</SP>, and back-coupled to deflecting electrode 17, and further deflecting plates 21, 22 are provided for moving the beam into alignment with one of the sets of teeth. Normally the beam is in equilibrium at the edge of one of the teeth-0, for example-under the influence of a constant bias applied to deflecting electrode 22. If a positive pulse-is applied via lead 42 to deflecting electrode 21 the beam is deflected upwardly, strikes plate 10 and as a result is deflected lengthwise to tooth 1<SP>1</SP>, and when the pulse subsides the beam is forced off tooth 11, strikes plate 10 and is deflected to tooth 1. 0, 1, 2 ... 9 are the counting teeth and 01, I<SP>1</SP>, 2<SP>1</SP> ... 9<SP>1</SP> the transfer teeth. When the beam is deflected off tooth 9 it strikes the short leg of L-shaped bar 14 which is back-coupled to deflecting electrode.19 and is driven up to the top boundary between 14 and 11. The part of the beam that strikes 11 drives plate 17 negative so that the beam is deflected to the left until it leaves 14 and falls on the edge of slot 49. When the pulse subsides the beam is returned via 0<SP>1</SP> to 0. At the same time the output derived from 14 is applied to the input of the next counting- device and the first device is ready for another count. If the applied pulse is negative instead of positive. the beam initially at 0 is driven on to the transfer bar 15 and along the bar to tooth 9. Further negative pulses return the beam to 0 via 9-47-8-47-7-47 &c., the apertures 47 providing stabilizing points for the beam, during each pulse. In this case the output is taken from 15. If the vertical deflecting voltage is excessive, the beam strikes bar 12 or 13 back-coupled to deflecting plates 24, 23 so that excessive deflection is prevented. Screens, Fig. 2 (not shown), suppress secondary emission from the various target elements. In general pulses may be applied to 42 or 43 or to both these leads. A number of calculating devices may be arranged in series, the first one counting units, the second one tens, the third one hundreds, and so on. In a modification, Figs. 3-5 (not shown), the bars 12, 13 are omitted and the teeth 0, 1 ... 9; 0<SP>1</SP>, 1<SP>1</SP> ... 9<SP>1</SP> are of saw-tooth form. In a further modification, Fig. 6, secondary emission is utilized. In Fig. 6, deflecting electrodes 18, 17 are controlled by secondary electron collectors 50, 51 located in the vicinity of plates 10, 11 respectively, and deflecting electrodes 19, 20 are controlled by secondary electron collectors 52, 53 located in L-shaped recesses formed by shields 55, 56 and performing the same function as beam return bars 14, 15 of Fig. 1. Shields 54, 55, 56 screen the various collectors from one another. The secondary emission ratio is preferably greater than unity, and is enhanced by tilting the target surfaces as shown.