- #1

Hannibal247

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Thread moved from the technical PF forums so no Homework Help Template is shown

Hello,

Im struggling a bit with this problem. (uploaded)
I don't know how to sketch the equivalent thermal circuit for any of them. Does it have to look like anything like that?

the thermal circuits are for b) parallel connectd right? and for aswell?

And I am getting wrong answers for a). Shouldnt it be like this?

Q= h

or are they all parallel? like this Q=A

My first thought was that the heat rate dissipating on the chip side is the same as the heat rate on the board side. why is this thought wrong? I am confused :D

thank you for your answers

Best regards

Im struggling a bit with this problem. (uploaded)

the thermal circuits are for b) parallel connectd right? and for aswell?

And I am getting wrong answers for a). Shouldnt it be like this?

Q= h

_{e}*A_{b}^{2}*55 + 1/((1/h_{i})+(L_{b}/k_{b}))*A_{b}^{2}*55or are they all parallel? like this Q=A

_{b}^{2}*1/((1/h_{i})+(L_{b}/k_{b})+(1/h_{e})) .My first thought was that the heat rate dissipating on the chip side is the same as the heat rate on the board side. why is this thought wrong? I am confused :D

thank you for your answers

Best regards