Spice Matrix

The entries of the Spice capacitance matrix represent the values of a network of 2-terminal capacitors. Imagine that between every pair of conductors (say, i and j, i different from j), you have a capacitor of value C^S_i,j.

In addition, let every conductor (say the i^th) have a capacitor C^S_i,0 connected to "ground" (the values of these grounded capacitors are the entries on the main diagonal of the Spice capacitance matrix).

The total charge on a given conductor will be found by summing up the charges on the individual capacitor plates connected to it.

Q_i = C^S_i,0 * Vi + C^S_i,1 * (V_i-V₁) + C^S_i,2 * (V_i -V₂) + ..... + C^S_i,N * (V_i -V_N)