A power transistor with three 0.8 mm diameter leads of a copper-silver alloy (k = 400 W/m-K) dissipates 3.5 Watts of power. The printed circuit board (PCB) on which the transistor is mounted is maintained at 30 C. The air temperature is 20 C and the heat transfer coefficient for the leads is 60 W/m² K. The length of the leads from the transistor to printed circuit board is 9.0 mm. (a) Determine the maximum lead temperature neglecting all convection effects. (b) Determine the maximum lead temperature if convection is present. T=20C h = 60 W/m²K Air Power Transistor Lead k = 400 W/m K TPCB = 30 C 9 mm

A power transistor with three 0.8 mm diameter leads of a copper-silver alloy (k = 400 W/m-K) dissipates 3.5 Watts of power. The printed circuit board (PCB) on which the transistor is mounted is maintained at 30 C. The air temperature is 20 C and the heat transfer coefficient for the leads is 60 W/m² K. The length of the leads from the transistor to printed circuit board is 9.0 mm. (a) Determine the maximum lead temperature neglecting all convection effects. (b) Determine the maximum lead temperature if convection is present. T=20C h = 60 W/m²K Air Power Transistor Lead k = 400 W/m K TPCB = 30 C 9 mm

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.10P: 1.10 A heat flux meter at the outer (cold) wall of a concrete building indicates that the heat loss...

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