Homework Help is Here – Start Your Trial Now!
Engineering
Mechanical Engineering
Consider a power transistor encapsulated in an aluminum case that is attached at its base to a square aluminum plate of thermal conductivity k= 240W/m.K, thickness L= 6mm, and width W= 20mm. The case is joined to the plate by screws that maintain a contact pressure of 1 bar, and the back surface of the plate transfers heat by natural convection and radiation to ambient air and large surroundings at T∞ =Tsur -25°C. The surface has an emissivity of ε=0.9, and the convection coefficient is h=4 W/m².K. The case is completely enclosed such that heat transfer may be assumed to occur exclusively through the base plate. a) If the air-filled aluminum-to-aluminum interface is characterized by an area of A₁=2×10-4 m² and contact resistance of R+c= 1.375 K/W, what is the maximum allowable power dissipation if the surface temperature of the case, Ts,c, is not to exceed 85°C? S,C' Transistor case Ts. Pelec S,C' Enclosure W Isur Base plate, (k,ε) Interface, Ac Air Th 801 b) How much should the h be to enhance power dissipation to 1 Watt?

Consider a power transistor encapsulated in an aluminum case that is attached at its base to a square aluminum plate of thermal conductivity k= 240W/m.K, thickness L= 6mm, and width W= 20mm. The case is joined to the plate by screws that maintain a contact pressure of 1 bar, and the back surface of the plate transfers heat by natural convection and radiation to ambient air and large surroundings at T∞ =Tsur -25°C. The surface has an emissivity of ε=0.9, and the convection coefficient is h=4 W/m².K. The case is completely enclosed such that heat transfer may be assumed to occur exclusively through the base plate. a) If the air-filled aluminum-to-aluminum interface is characterized by an area of A₁=2×10-4 m² and contact resistance of R+c= 1.375 K/W, what is the maximum allowable power dissipation if the surface temperature of the case, Ts,c, is not to exceed 85°C? S,C' Transistor case Ts. Pelec S,C' Enclosure W Isur Base plate, (k,ε) Interface, Ac Air Th 801 b) How much should the h be to enhance power dissipation to 1 Watt?

Elements Of Electromagnetics
Elements Of Electromagnetics
7th Edition
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Sadiku, Matthew N. O.
ChapterMA: Math Assessment
Section: Chapter Questions
Problem 1.1MA
See similar textbooks
icon
Related questions
Question
Consider a power transistor encapsulated in an aluminum case that is attached at its base to a square aluminum plate of thermal conductivity k= 240W/m.K, thickness L= 6mm, and width W= 20mm. The case is joined to the plate by screws that maintain a contact pressure of 1 bar, and the back surface of the plate transfers heat by natural convection and radiation to ambient air and large surroundings at T∞ =Tsur -25°C. The surface has an emissivity of ε=0.9, and the convection coefficient is h=4 W/m².K. The case is completely enclosed such that heat transfer may be assumed to occur exclusively through the base plate. a) If the air-filled aluminum-to-aluminum interface is characterized by an area of A₁=2×10-4 m² and contact resistance of R+c= 1.375 K/W, what is the maximum allowable power dissipation if the surface temperature of the case, Ts,c, is not to exceed 85°C? S,C' Transistor case Ts. Pelec S,C' Enclosure W Isur Base plate, (k,ε) Interface, Ac Air Th 801 b) How much should the h be to enhance power dissipation to 1 Watt?
Transcribed Image Text:Consider a power transistor encapsulated in an aluminum case that is attached at its base to a square aluminum plate of thermal conductivity k= 240W/m.K, thickness L= 6mm, and width W= 20mm. The case is joined to the plate by screws that maintain a contact pressure of 1 bar, and the back surface of the plate transfers heat by natural convection and radiation to ambient air and large surroundings at T∞ =Tsur -25°C. The surface has an emissivity of ε=0.9, and the convection coefficient is h=4 W/m².K. The case is completely enclosed such that heat transfer may be assumed to occur exclusively through the base plate. a) If the air-filled aluminum-to-aluminum interface is characterized by an area of A₁=2×10-4 m² and contact resistance of R+c= 1.375 K/W, what is the maximum allowable power dissipation if the surface temperature of the case, Ts,c, is not to exceed 85°C? S,C' Transistor case Ts. Pelec S,C' Enclosure W Isur Base plate, (k,ε) Interface, Ac Air Th 801 b) How much should the h be to enhance power dissipation to 1 Watt?
Expert Solution
steps

Step by step

Solved in 2 steps with 3 images

SEE SOLUTIONCheck out a sample Q&A here
Blurred answer
Similar questions
Recommended textbooks for you
Elements Of Electromagnetics
Elements Of Electromagnetics
Mechanical Engineering
ISBN:
9780190698614
Author:
Sadiku, Matthew N. O.
Publisher:
Oxford University Press
Mechanics of Materials (10th Edition)
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:
9780134319650
Author:
Russell C. Hibbeler
Publisher:
PEARSON
Thermodynamics: An Engineering Approach
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:
9781259822674
Author:
Yunus A. Cengel Dr., Michael A. Boles
Publisher:
McGraw-Hill Education
Control Systems Engineering
Control Systems Engineering
Mechanical Engineering
ISBN:
9781118170519
Author:
Norman S. Nise
Publisher:
WILEY
Mechanics of Materials (MindTap Course List)
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:
9781337093347
Author:
Barry J. Goodno, James M. Gere
Publisher:
Cengage Learning
Engineering Mechanics: Statics
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:
9781118807330
Author:
James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:
WILEY
SEE MORE TEXTBOOKS