Power switching circuitry has a heat absorbing structure, and a heat conductive substrate having power switching components on a first surface and a second surface adjacent to the heat absorbing structure. Electrically conductive members, comprising first and second members, are on the first surface and extend along a first axis orthogonal to the heat conductive substrate. The second portion is more remote from the heat conductive substrate, and has a smaller cross-sectional area than, the first portion to define a shoulder region orthogonal to the first axis. A circuit board is located on the shoulder regions, with the second portions extending through the circuit board. An urging mechanism urges the circuit board against the shoulder regions, whereby the electrically conductive members provide a current path between the heat conductive substrate and the circuit board, and urge the heat conductive substrate into thermal contact with the heat absorbing structure.