16. Nota
17. A heat sink provides ________ thermal resistance between case and air.
(a) a high
(b) a low
(c) the same
(d) None of the above
18. Class D operation can achieve power efficiency of over ________.
(a) 90%
(b) 78.5%
(c) 50%
(d) 25%
19. ________ amplifiers have the highest overall efficiency.
(a) Class A
(b) Class B or AB
(c) Class C
(d) Class D
20. A silicon power transistor is operated with a heat sink ( θSA = 1.5ºC/W). The transistor, rated at 150 W (25ºC), has θJC = 0.5º C/W, and the mounting insulation has θCS = 0.6 ºC/W. What is the maximum power that can be dissipated if the ambient temperature is 50ºC and TJmax = 200 ºC?
(a) 61.5 W
(b) 60.0 W
(c) 57.7 W
(d) 55.5 W
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