The effect of electronic module's shape on friction factors and heat transfer coefficients in rectangular channels with two opposite walls, included module's was determined in electronic circuit boards by keeping pressure drop constant in a given range. Generally for electronic modules, square shape is used. But in this study, different shape of modules which is cylindrical was investigated. Two different heights of cylindrical parameters, 3 mm and 1.5 mm, were used in order to find the effect of the height on heat transfer. Experiments were realized for channel height 6, 8 and 10 mm, for both modules height. The investigation was performed with both laminar and turbulent forced flow for Reynolds number from 250 to 7000. The wall temperature was held constant at 85 degrees C. The global measurement technique was used to determine the temperature difference and pressure drop in the test duct. The result revealed that the heat transfer performance of module height 3 mm is much better than the module height 1.5 mm.