Electronic Devices - Power Amplifiers - Discussion

Discussion Forum : Power Amplifiers - General Questions (Q.No. 21)
21.
Determine what maximum dissipation will be allowed for a 70-W silicon transistor (rated at 25ºC) if derating is required above 25ºC by a derating factor of 0.6 W/ºC at a case temperature of 100º.
25 W
30 W
35 W
40 W
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
2 comments Page 1 of 1.

R.Padmavathy said:   8 years ago
PD(1000) = PD(250)- (1000 - 250 )(0.6 W/°C).
= 70 W - 750(0.6 W/°C).
= 25 W.

Twinkal said:   1 decade ago
At a case temperature of 100deg = 100-25 = 75 deg c.

Derating factor 0.6W/degc above 25deg c.

Than 75 X 0.6 = 45w.

max. dissipation = 70-45 = 25w.
(1)

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