Analogue computer for solving polynomial equations

Abstract

An analogue computer has two or more multiplication modules. Each module provides an output signal representing the product of the magnitude of an analogue input signal to the module and the factor represented by a common multiplier signal controlling the module. Output signals of two or more modules are combined to provide a composite signal. A comparator compares the composite signal with a reference level and adjusts the common multiplier signal so as to maintain the composite signal substantially equal to the reference level. Modules are connected in chains with the output of one module connected to the input of the next module in the chain. Output signals from the various modules represent terms in the polynominal expressions of equations which the computer can solve. Potentiometers allow these output signals to be scaled in accordance with the constant coefficients of the terms. The input of the first module in any chain is fed with a constant reference signal or an analogue signal representing a known or measured variable in the equation. The computer causes the factor represented by the common multiplier signal to represent the unknown variable of the equation. One example of the computer has two chains each of three modules and calculates the density of a gas from measured values of temperature and pressure.