Question

For a given transistor, the thermal resistance is 8°C/W and for the ambient temperature TA is 27°C. If the transistor dissipates 3W of power, calculate the junction temperature (TJ).

(a) 51°C

(b) 27°C

(c) 67°C

(d) 77°C

I had been asked this question during an interview for a job.

My question is based upon Thermal Stability in division Transistor Biasing and Thermal Stabilization of Electronic Devices & Circuits

Answer 1

Correct answer is (a) 51°C

Easy explanation: We know, TJ-TA=HPD

TJ=TA+HPD=27+8*3=51°C.