GB756328A - Improvements in electrical equation-solvers - Google Patents

Abstract

756,328. Electric analogue calculating apparatus. ASSOCIATED ELECTRICAL INDUSTRIES, Ltd. Aug. 14, 1953 [Oct. 17, 1952], No. 26118/52. Class 37. An electric analogue apparatus for solving simultaneous equations comprises a resistance chain corresponding to each unknown whose component resistances represent the coefficients of equations comprising the same unknown and in which respective variable currents simulating the values of the appropriate unknowns flow, so that the voltages across the individual resistances represent corresponding component terms of the individual equations, and a single summing resistance corresponding to each equation; which is traversed in parallel by currents proportional to the voltages across the component resistances of the equation and representing the component terms thereof, additively combined in appropriate sense or phase to develop a voltage across the summing resistance representing the algebraic sum of the component terms, which may be reduced to zero by iteratively adjusting the resistance currents to represent the solution values of the unknowns. In a circuit for solving simultaneous equations of the kind set forth in Specification 756,325 the several analogue resistance chains (RxO, Rs0, - b1,-b2); (Rx1, Rs1, all, a21); (Rx2, Rs2, a12, a22) are supplied from a source of direct voltage; the first chain being connected between the positive busbar and earth while the second and third chains are connected between earth and the positive or negative busbar by switches C1, C2, and the resultant voltage drops across resistances (- b1, a11, a12) and (- b2, a21, a22) analogous to the terms of the equations to be solved are respectively coupled over change-over switches So1, S11, S21 and So2, S12, S22 determining the signs of the coefficients and through high series resistances Rp to summing resistances Rs1, Rs2 corresponding one to each equation; the output voltages across which represent the residuals P1, P2 so that by keeping Io constant and iteratively adjusting I1, I2 until PI, P2 are simultaneously reduced to zero, the solution values x1 x2 are determined from the voltage drops across Rs1, Rs2. The residuals may be displayed simultaneously by the cathode-ray apparatus described in Specification 754,113.