Patent GB-993120-A (GB)
Title: Improvements in or relating to conditionable conversion networks and the like
Inventor: MACKAY DONALD MACCRIMMON
IPC: H01C10/02
Filed: 1961-04-10
Abstract: 993,120. Learning circuits. NATIONAL RESEARCH DEVELOPMENT CORPORATION. April 10, 1962 [April 10, 1961], No. 12887/61. Heading G4R. A conditional converter matrix consisting of row and column current paths uses an electrolytic liquid to provide variable impedance between the crosspoints of the paths by forming a cell. A basic cell consists of two conductors 1, 2, Fig. 1 immersed in liquid 3. If electrode 1 is positive an insulating film 4 builds up and the resistance between 1 and 2 will increase. By reversing the polarities the resistance decreases. The cell may be formed at the cross-over between two wires by coating one of them with an absorbent material 8 such as cotton which is impregnated with electrolyte. In Fig. 4 the column conductors are formed by the electrolyte flowing from nozzles 18 down woollen strings 14 connected at the top to conductors 15. The transfer of current between the row wires and the electrolyte causes the resistive film to build up or disappear. The network can be inactivated by cutting off the electrolyte or some columns can be put out of action by shutting their nozzles 18. Instead of woollen strings, tubes full of electrolyte may be used, the tubes having bellows at the bottom so that the electrolyte can be raised and lowered into and out of contact with the row wires. In another form the tubes tip for the same purpose. In Fig. 7 a number of networks 35 is provided, each in a separate tank having inlet and outlet valves. Networks can be made operative or inoperative by controlling the valves. Another type of cell Fig. 8 consists of a tank 51, a tube 52 full of electrolyte making contact with an electrode 53 at the top. The other electrode 54 is large. Current between the electrodes causes metal to be transferred to the tip 55 of electrode 53 or from it back to the electrode 54. The more metal transferred to the tip 55 the lower the resistance between the two electrode 53, 54. D.C. potentials therefore change the resistance by A.C. potentials do not affect it. A number of electrodes 53 will coact with each electrode 55. In Fig. 11 the electrode 83 are at the ends of bores 81 with diverging lower ends. The metallic fibre deposited in the bore can be deflected in the diverging portion by applying a magnetic field in one direction or the other so as to be nearer one or other of electrides 84, 85. The network can be conditioned by a feed back action as shown in Fig. 13. The input combination in row wires 102 is applied by switches 104 connected to a two-position switch 106. Contact 107 connects to a variable voltage source 109 and contact 108 with twopolarity source 111. The column conductors 103 are connected via relays 113 and indicators 105 to earth. To condition the network the switch 106 is set to contact 107 and the voltage of source 109 is raised slowly. According to the initial random setting of the cross point resistances of of the indicators 105 will operate first. If this is the correct conversion of the input pattern, the switch 106 is changed to contact 108 and the source 111 is set to one of its polarities (say +ve for correct). When switch 112 is closed current flows through the selected switches 104 and the cross over points to the column conductor, the relay contact being closed. This increases the couplings at the cross overs. If the indicator 105 is wrong the other polarity is selected and the process repeated to reduce the cross-over coupling.