Abstract: An electrical assembly incorporates a multilayer printed circuit board comprising a flexible electrically insulating circuit board laminate with electrical conductors for connecting to terminals on rigid slab-like heat-dissipating components such as circuit or component packages or carriers. A separate rigid metallic heat-sinking or spreading plate is applied, having protruding thermally conducting pillars passing through holes in the circuit board laminate to contact the components. A further rigid plate overlies the components and is clamped by clips or bolts to the plate. Compliant means such as springs of deformable and elastic rubber or plastics material is provided intermediate the further plate and the top of the components to accommodate difference in height or thickness between the components while transmitting pressure from the further plate to the top of the component to ensure contact between the components and the pillars on the heat sinking or spreading plate.