# Heat Sink Calculation

Discussion in 'Homework Help' started by dmag0006, Jun 20, 2011.

1. ### dmag0006 Thread Starter New Member

Dec 8, 2010
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Hi! I need to design a heatsink for this circuit. Now I know how this should be done however I am having big problems finding Pdmax for such a circuit which is stopping me from finding a value for the heatsink. Does anyone know any equations I could use to do so?Thanks!

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2. ### beenthere Retired Moderator

Apr 20, 2004
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Assume your transistor can have a range of currents through it (treat it as a variable resistor). You have two fixed resistors and a voltage source for the series circuit. Which value for the resistance of the ML15003 causes the most power to get dissipated?

3. ### dmag0006 Thread Starter New Member

Dec 8, 2010
17
0
I'm not sure if I understood you well (I am still relatively a beginner as you can see) however I was told I need to do some integration in order to get Pdmax. Now I know how this was mode for other circuits such as ones which are push-pull...however I am finding this quite confusing!

4. ### beenthere Retired Moderator

Apr 20, 2004
15,815
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5. ### Jony130 AAC Fanatic!

Feb 17, 2009
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Your amp work in class A so Pdmax = Vce * Ic = 10V * 0.25A = 2.5W

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