Abstract: A plurality of insulated carrier plates are selectively coated with an electrical conductor. Each plate has a pair of flat mounting faces and a plurality of edge faces between the mounting faces. The edge faces include a plurality of spaced-apart, flat, coplanar protrusions projecting from the remainder of the edge faces. One of the mounting faces of each plate is coated with a plurality of mutually isolated first conductive layers, which extend to the respective protrusions. The other mounting face of each plate is coated with a plurality of mutually isolated second conductive layers, which extend to the respective protrusions. The plates are stacked face-to-face so the respective protrusions of adjacent plates adjoin. A conductive layer is then applied to the adjoining protrusions of the stacked plates to the exclusion of the remainder of the edge faces so as to interconnect electrically the respective first and second conductive layers.