Abstract: A method is described. The method includes calculating electric and/or magnetic fields in free space in response to: i) respective positions and motions of one or more charges and/or one or more current loops in the free space; ii) charges on nodes in the electrical circuit in the free space; iii) charge motions in the electrical circuit. The method includes calculating new respective positions and motions of the one or more charges and/or one or more current loops in the free space in response to respective forces applied to the one or more charges and/or the one or more current loops by the electric and/or magnetic fields. The method includes calculating new charges on nodes within the electrical circuit and new charge motions within the electrical circuit in response to the new positions and motions of the one or more charges and/or one or more current loops in free space, the charges on the nodes in the electrical circuit and the charge motions in the electrical circuit.