Electronic module

Electronic module of printed circuit board with electronic components on one side and its other side in heat conducting contact with a heat sink enables the electronic components to be sealed from ambient atmosphere and thus unpackaged chips may be used. The modules are mountable in a support frame with air cooling passages of the heat sinks extending vertically for convected cooling air. In each module, a resistor network may extend into a cavity formed in a heat exchange rib and an electronic chip, perhaps unpackaged in the sealed environment, may be in heat conductive relationship with the heat sink.