Analogue computers using magnetic amplifiers

THIS analogue computing technique uses direct currents as variables. These currents are summed by magnetic amplifiers to perform addition and subtraction operations. Products, quotients, roots, and powers are obtained by summing other currents that are proportional to the logarithms of the variables. These logarithmic currents are obtained by networks of 5 germanium or silicon diodes and 11 precision resistors. As the input current increases, the diodes in the circuit cut in sequentially to shape the output current according to a logarithmic curve. A voltage is supplied to a voltage divider in the network controlling the switching points of these diodes.