A PWB 6 X 9 inches has heat load uniformly distributed with 12.0 watts is natural convection cooled and is oriented vertical.
The ambient temperature is 25 C. On it is mounted a 24 pin dip (2 In X 0.5 In) with a 10 mil air gap and a surface mount resistor.
The pin size is 0.017 X 0.005 inch and 0.1 in long. The surface mount resistor has two tabs 0.1 in square and 15 mils thick. The tab and pins are made of copper. The junction to case resistance of the DIP is 24 C/W.
The power of the dip is 120 milli-watts and that of the resistor is 212 milliwatt.
Neglect heat transfer from the components to air.
What is the temperature of the DIP and the resistor when the 6 inch side is vertical and when the 9 inch side is vertical.
If one side of the PWB is placed close to a wall what is the temperature? Assume ?JC = 26 C/W.
The resistor is mounted on a 6 mil solder pad with a conductivity of 127 W/M/K. What is the temperature of the DIP and the resistor?