By Ian Darney
A method of simulating the distribution of current on the surfaces of conductors of a cable form is described. This is dramatically more useful to designers than multi-coloured images of electromagnetic fields.
This is done by representing the surface of each conductor as an array of elemental conductors. The technique is introduced here by simulating the current distribution in two parallel conductors when these are short-circuited at one end and a voltage step of 1 Volt is applied at the other. Calculating the sum of the currents in the elemental conductors of each composite gives the total current in that conductor. There is then enough data to calculate the characteristic impedance, inductance, and capacitance of each conductor, and a circuit model of this simple assembly is derived.